Guidance, Navigation, and Control Considerations for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Mitchell, Doyce P.; Kim, Tony

2015-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation NTP system could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of a first generation NTP in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NTP project could also help enable high performance fission power systems and Nuclear Electric Propulsion (NEP). Guidance, navigation, and control of NTP may have some unique but manageable characteristics.

Inorganic biochemistry with short-lived radioisotopes as nuclear probes

NASA Astrophysics Data System (ADS)

Tröger, W.; Butz, T.

2000-12-01

Metal ions are ubiquitous in the biosphere. In living organisms metalloproteins with specifically designed metal cores perform vital chemical processes. On the other hand, several heavy metals are detrimental to living organisms and nature has developed effective enzymatic detoxification systems which convert toxic metal ions to less toxic species. The nuclear spectroscopy technique Time Differential Perturbed Angular Correlation (TDPAC) of γ-rays uses radioactive isotopes as nuclear probes in these metal cores to obtain a better understanding of the structural and functional significance of these metal cores by monitoring the nuclear quadrupole interaction of the TDPAC probe. Since this technique is based on the nuclear decay, it is also applicable under physiological conditions, i.e., especially at picomolar concentrations. For these studies an indispensable prerequisite is the production of the TDPAC probes with highest possible specific activity and purity as is done by the on-line mass separator ISOLDE at CERN in Geneva.

Drug and alcohol abuse: the bases for employee assistance programs in the nuclear-utility industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radford, L.R.; Rankin, W.L.; Barnes, V.

This report describes the nature, prevalence, and trends of drug and alcohol abuse among members of the US adult population and among personnel in non-nuclear industries. Analogous data specific to the nuclear utility industry are not available, so these data were gathered in order to provide a basis for regulatory planning. The nature, prevalence, and trend inforamtion was gathered using a computerized literature, telephone discussions with experts, and interviews with employee assistance program representatives from the Seattle area. This report also evaluates the possible impacts that drugs and alcohol might have on nuclear-related job performance, based on currently available nuclearmore » utility job descriptions and on the scientific literature regarding the impairing effects of drugs and alcohol on human performance. Employee assistance programs, which can be used to minimize or eliminate job performance decrements resulting from drug or alcohol abuse, are also discussed.« less

77 FR 43506 - DoD Unclassified Controlled Nuclear Information (UCNI)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-25

... Systems. (i) Information on the layout or design of security and alarm systems at a specific DoD SNM or... information is not observable from a public area. (iii) Performance characteristics of installed systems. (5... 0790-AI64 DoD Unclassified Controlled Nuclear Information (UCNI) AGENCY: Department of Defense. ACTION...

76 FR 68792 - Agency Information Collection Activities: Submission for the Office of Management and Budget (OMB...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-07

...: Submission for the Office of Management and Budget (OMB) Review; Comment Request AGENCY: Nuclear Regulatory... Control and Accounting of Special Nuclear Material. 3. Current OMB approval number: 3150-0123. 4. The form... requirements for material control and accounting of SNM, and specific performance-based regulations for...

76 FR 24831 - Site-Specific Analyses for Demonstrating Compliance With Subpart C Performance Objectives

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-03

... available under ADAMS accession number ML111040419, and the ``Technical Analysis Supporting Definition of... NUCLEAR REGULATORY COMMISSION 10 CFR Part 61 RIN 3150-AI92 [NRC-2011-0012] Site-Specific Analyses...-level radioactive waste disposal facilities to conduct site-specific analyses to demonstrate compliance...

Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naus, Dan J

The objective of this study was to provide a primer on the environmental effects that can affect the durability of nuclear power plant concrete structures. As concrete ages, changes in its properties will occur as a result of continuing microstructural changes (i.e., slow hydration, crystallization of amorphous constituents, and reactions between cement paste and aggregates), as well as environmental influences. These changes do not have to be detrimental to the point that concrete will not be able to meet its performance requirements. Concrete, however, can suffer undesirable changes with time because of improper specifications, a violation of specifications, or adversemore » performance of its cement paste matrix or aggregate constituents under either physical or chemical attack. Contained in this report is a discussion on concrete durability and the relationship between durability and performance, a review of the historical perspective related to concrete and longevity, a description of the basic materials that comprise reinforced concrete, and information on the environmental factors that can affect the performance of nuclear power plant concrete structures. Commentary is provided on the importance of an aging management program.« less

Transmutation of Radioactive Nuclear Waste — Present Status and Requirement for the Problem-Oriented Nuclear Database: Approach to Scheduling the Experiments (Reactor, Target, Blanket)

NASA Astrophysics Data System (ADS)

Artisyuk, V.; Ignatyuk, A.; Korovin, Yu.; Lopatkin, A.; Matveenko, I.; Stankovskiy, A.; Titarenko, Yu.

2005-05-01

Transmutation of nuclear wastes (Minor Actinides and Long-Lived Fission Products) remains an important option to reduce the burden of high-level waste on final waste disposal in deep geological structures. Accelerator-Driven Systems (ADS) are considered as possible candidates to perform transmutation due to their subcritical operation mode that eliminates some of the serious safety penalties unavoidable in critical reactors. Specific requirements to nuclear data necessary for ADS transmutation analysis is the main subject of the ISTC Project ♯2578 which started in 2004 to identify the areas of research priorities in the future. The present paper gives a summary of ongoing project stressing the importance of nuclear data for blanket performance (reactivity behavior with associated safety characteristics) and uncertainties that affect characteristics of neutron producing target.

Affordable Development of a Nuclear Cryogenic Propulsion Stage

NASA Technical Reports Server (NTRS)

Houts, M. G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

2012-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. The foundation provided by development and utilization of a NCPS could enable development of extremely high performance systems. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

The clinical evaluation of the CADence device in the acoustic detection of coronary artery disease.

PubMed

Thomas, Joseph L; Ridner, Michael; Cole, Jason H; Chambers, Jeffrey W; Bokhari, Sabahat; Yannopoulos, Demetris; Kern, Morton; Wilson, Robert F; Budoff, Matthew J

2018-06-23

The noninvasive detection of turbulent coronary flow may enable diagnosis of significant coronary artery disease (CAD) using novel sensor and analytic technology. Eligible patients (n = 1013) with chest pain and CAD risk factors undergoing nuclear stress testing were studied using the CADence (AUM Cardiovascular Inc., Northfield MN) acoustic detection (AD) system. The trial was designed to demonstrate non-inferiority of AD for diagnostic accuracy in detecting significant CAD as compared to an objective performance criteria (sensitivity 83% and specificity 80%, with 15% non-inferiority margins) for nuclear stress testing. AD analysis was blinded to clinical, core lab-adjudicated angiographic, and nuclear data. The presence of significant CAD was determined by computed tomographic (CCTA) or invasive angiography. A total of 1013 subjects without prior coronary revascularization or Q-wave myocardial infarction were enrolled. Primary analysis was performed on subjects with complete angiographic and AD data (n = 763) including 111 subjects (15%) with severe CAD based on CCTA (n = 34) and invasive angiography (n = 77). The sensitivity and specificity of AD were 78% (p = 0.012 for non-inferiority) and 35% (p < 0.001 for failure to demonstrate non-inferiority), respectively. AD results had a high 91% negative predictive value for the presence of significant CAD. AD testing failed to demonstrate non-inferior diagnostic accuracy as compared to the historical performance of a nuclear stress OPC due to low specificity. AD sensitivity was non-inferior in detecting significant CAD with a high negative predictive value supporting a potential value in excluding CAD.

Species-specific challenges in dog cloning.

PubMed

Kim, G A; Oh, H J; Park, J E; Kim, M J; Park, E J; Jo, Y K; Jang, G; Kim, M K; Kim, H J; Lee, B C

2012-12-01

Somatic cell nuclear transfer (SCNT) is now an established procedure used in cloning of several species. SCNT in dogs involves multiple steps including the removal of the nuclear material, injection of a donor cell, fusion, activation of the reconstructed oocytes and finally transfer to a synchronized female recipient. There are therefore many factors that contribute to cloning efficiency. By performing a retrospective analysis of 2005-2012 published papers regarding dog cloning, we define the optimum procedure and summarize the specific feature for dog cloning. © 2012 Blackwell Verlag GmbH.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rauch, Eric Benton

This report serves as a comprehensive overview of the Extended Storage of Used Nuclear Fuel work performed for the Material Protection, Accounting and Control Technologies campaign under the Department of Energy Office of Nuclear Energy. This paper describes a signature based on the source and fissile material distribution found within a population of used fuel assemblies combined with the neutron absorbers found within cask design that is unique to a specific cask with its specific arrangement of fuel. The paper describes all the steps used in producing and analyzing this signature from the beginning to the project end.

A potassium Rankine multimegawatt nuclear electric propulsion concept

NASA Technical Reports Server (NTRS)

Baumeister, E.; Rovang, R.; Mills, J.; Sercel, J.; Frisbee, R.

1990-01-01

Multimegawatt nuclear electric propulsion (NEP) has been identified as a potentially attractive option for future space exploratory missions. A liquid-metal-cooled reactor, potassium Rankine power system that is being developed is suited to fulfill this application. The key features of the nuclear power system are described, and system characteristics are provided for various potential NEP power ranges and operational lifetimes. The results of recent mission studies are presented to illustrate some of the potential benefits to future space exploration to be gained from high-power NEP. Specifically, mission analyses have been performed to assess the mass and trip time performance of advanced NEP for both cargo and piloted missions to Mars.

Gamma-ray imaging system for real-time measurements in nuclear waste characterisation

NASA Astrophysics Data System (ADS)

Caballero, L.; Albiol Colomer, F.; Corbi Bellot, A.; Domingo-Pardo, C.; Leganés Nieto, J. L.; Agramunt Ros, J.; Contreras, P.; Monserrate, M.; Olleros Rodríguez, P.; Pérez Magán, D. L.

2018-03-01

A compact, portable and large field-of-view gamma camera that is able to identify, locate and quantify gamma-ray emitting radioisotopes in real-time has been developed. The device delivers spectroscopic and imaging capabilities that enable its use it in a variety of nuclear waste characterisation scenarios, such as radioactivity monitoring in nuclear power plants and more specifically for the decommissioning of nuclear facilities. The technical development of this apparatus and some examples of its application in field measurements are reported in this article. The performance of the presented gamma-camera is also benchmarked against other conventional techniques.

Rover nuclear rocket engine program: Overview of rover engine tests

NASA Technical Reports Server (NTRS)

Finseth, J. L.

1991-01-01

The results of nuclear rocket development activities from the inception of the ROVER program in 1955 through the termination of activities on January 5, 1973 are summarized. This report discusses the nuclear reactor test configurations (non cold flow) along with the nuclear furnace demonstrated during this time frame. Included in the report are brief descriptions of the propulsion systems, test objectives, accomplishments, technical issues, and relevant test results for the various reactor tests. Additionally, this document is specifically aimed at reporting performance data and their relationship to fuel element development with little or no emphasis on other (important) items.

The advisability of prototypic testing for space nuclear systems

NASA Astrophysics Data System (ADS)

Lenard, Roger X.

2005-07-01

From October 1987 until 1993, the US Department of Defense conducted the Space Nuclear Thermal Propulsion program. This program's objective was to design and develop a high specific impulse, high thrust-to-weight nuclear thermal rocket engine for upper stage applications. The author was the program manager for this program until 1992. Numerous analytical, programmatic and experimental results were generated during this period of time. This paper reviews the accomplishments of the program and highlights the importance of prototypic testing for all aspects of a space nuclear program so that a reliable and safe system compliant with all regulatory requirements can be effectively engineered. Specifically, the paper will recount how many non-prototypic tests we performed only to have more representative tests consistently generate different results. This was particularly true in area of direct nuclear heat generation. As nuclear tests are generally much more expensive than non-nuclear tests, programs attempt to avoid such tests in favor of less expensive non-nuclear tests. Each time this approach was followed, the SNTP program found these tests to not be verified by nuclear heated testing. Hence the author recommends that wherever possible, a spiral development approach that includes exploratory and confirmatory experimental testing be employed to ensure a viable design.

Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

NASA Technical Reports Server (NTRS)

Bradley, D. E.; Mireles, O. R.; Hickman, R. R.

2011-01-01

Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames.1,2 Conventional storable propellants produce average specific impulse. Nuclear thermal rockets capable of producing high specific impulse are proposed. Nuclear thermal rockets employ heat produced by fission reaction to heat and therefore accelerate hydrogen, which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K), and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited.3 The primary concern is the mechanical failure of fuel elements that employ high-melting-point metals, ceramics, or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. The purpose of the testing is to obtain data to assess the properties of the non-nuclear support materials, as-fabricated, and determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures. The fission process of the planned fissile material and the resulting heating performance is well known and does not therefore require that active fissile material be integrated in this testing. A small-scale test bed designed to heat fuel element samples via non-contact radio frequency heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

Technology Implementation Plan: Irradiation Testing and Qualification for Nuclear Thermal Propulsion Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison, Thomas J.; Howard, Richard H.; Rader, Jordan D.

This document is a notional technology implementation plan (TIP) for the development, testing, and qualification of a prototypic fuel element to support design and construction of a nuclear thermal propulsion (NTP) engine, specifically its pre-flight ground test. This TIP outlines a generic methodology for the progression from non-nuclear out-of-pile (OOP) testing through nuclear in-pile (IP) testing, at operational temperatures, flows, and specific powers, of an NTP fuel element in an existing test reactor. Subsequent post-irradiation examination (PIE) will occur in existing radiological facilities. Further, the methodology is intended to be nonspecific with respect to fuel types and irradiation or examinationmore » facilities. The goals of OOP and IP testing are to provide confidence in the operational performance of fuel system concepts and provide data to program leadership for system optimization and fuel down-selection. The test methodology, parameters, collected data, and analytical results from OOP, IP, and PIE will be documented for reference by the NTP operator and the appropriate regulatory and oversight authorities. Final full-scale integrated testing would be performed separately by the reactor operator as part of the preflight ground test.« less

Neutron dose estimation in a zero power nuclear reactor

NASA Astrophysics Data System (ADS)

Triviño, S.; Vedelago, J.; Cantargi, F.; Keil, W.; Figueroa, R.; Mattea, F.; Chautemps, A.; Santibañez, M.; Valente, M.

2016-10-01

This work presents the characterization and contribution of neutron and gamma components to the absorbed dose in a zero power nuclear reactor. A dosimetric method based on Fricke gel was implemented to evaluate the separation between dose components in the mixed field. The validation of this proposed method was performed by means of direct measurements of neutron flux in different positions using Au and Mg-Ni activation foils. Monte Carlo simulations were conversely performed using the MCNP main code with a dedicated subroutine to incorporate the exact complete geometry of the nuclear reactor facility. Once nuclear fuel elements were defined, the simulations computed the different contributions to the absorbed dose in specific positions inside the core. Thermal/epithermal contributions of absorbed dose were assessed by means of Fricke gel dosimetry using different isotopic compositions aimed at modifying the sensitivity of the dosimeter for specific dose components. Clear distinctions between gamma and neutron capture dose were obtained. Both Monte Carlo simulations and experimental results provided reliable estimations about neutron flux rate as well as dose rate during the reactor operation. Simulations and experimental results are in good agreement in every positions measured and simulated in the core.

Safe, Affordable, Nuclear Thermal Propulsion Systems

NASA Technical Reports Server (NTRS)

Houts, M. G.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Doughty, G. E.

2014-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

The Nuclear Cryogenic Propulsion Stage

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

2014-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progres made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

Nuclear Cryogenic Propulsion Stage for Mars Exploration

NASA Technical Reports Server (NTRS)

Houts, M. G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

2012-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

Nuclear Thermal Propulsion for Advanced Space Exploration

NASA Technical Reports Server (NTRS)

Houts, M. G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

2012-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

Reformation of Regulatory Technical Standards for Nuclear Power Generation Equipments in Japan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikio Kurihara; Masahiro Aoki; Yu Maruyama

2006-07-01

Comprehensive reformation of the regulatory system has been introduced in Japan in order to apply recent technical progress in a timely manner. 'The Technical Standards for Nuclear Power Generation Equipments', known as the Ordinance No.622) of the Ministry of International Trade and Industry, which is used for detailed design, construction and operating stage of Nuclear Power Plants, was being modified to performance specifications with the consensus codes and standards being used as prescriptive specifications, in order to facilitate prompt review of the Ordinance with response to technological innovation. The activities on modification were performed by the Nuclear and Industrial Safetymore » Agency (NISA), the regulatory body in Japan, with support of the Japan Nuclear Energy Safety Organization (JNES), a technical support organization. The revised Ordinance No.62 was issued on July 1, 2005 and is enforced from January 1 2006. During the period from the issuance to the enforcement, JNES carried out to prepare enforceable regulatory guide which complies with each provisions of the Ordinance No.62, and also made technical assessment to endorse the applicability of consensus codes and standards, in response to NISA's request. Some consensus codes and standards were re-assessed since they were already used in regulatory review of the construction plan submitted by licensee. Other consensus codes and standards were newly assessed for endorsement. In case that proper consensus code or standards were not prepared, details of regulatory requirements were described in the regulatory guide as immediate measures. At the same time, appropriate standards developing bodies were requested to prepare those consensus code or standards. Supplementary note which provides background information on the modification, applicable examples etc. was prepared for convenience to the users of the Ordinance No. 62. This paper shows the activities on modification and the results, following the NISA's presentation at ICONE-13 that introduced the framework of the performance specifications and the modification process of the Ordinance NO. 62. (authors)« less

Novel Separation of Actinides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mariella, R

The separation of actinides and other elements of interest for nuclear forensics and threat reduction is currently performed using decades-old chemistries and ion-exchange columns. We propose to determine the technical feasibility of a novel method for separating actinide ions in solution. This method is based upon isotachophoresis (ITP), which has been applied in the purification of pharmaceuticals and other biochemical applications. This technique has the potential to separate inorganic ions more effectively than existing methods, which is key to analyzing very small samples. We will perform a quantitative assessment of the effectiveness of specific isotachophoretic approaches including predicting the physicalmore » and chemical properties, such as ion mobility, of inorganic ions under specific solvent conditions using a combination of ab initio calculations and semi-empirical methods. We expect to obtain a thorough understanding of the analytical systems parameters under which ITP is most effective for the separation of inorganic samples, including the influence of the double layer surrounding actinide ions, the Debye length for different ions and ion complexes, and Debye-Hueckel limits. Inorganic separations are key to nuclear forensics for countering terrorism and nuclear proliferation. If found to be feasible and potentially superior to currently used separation approaches, ITP could provide the conceptual basis for an improved means to separate samples of nuclear explosion debris for nuclear forensic analysis, in support of the Laboratory's missions in homeland and national security.« less

Characterization of Large Volume CLYC Scintillators for Nuclear Security Applications

NASA Astrophysics Data System (ADS)

Soundara-Pandian, Lakshmi; Tower, J.; Hines, C.; O'Dougherty, P.; Glodo, J.; Shah, K.

2017-07-01

We report on our development of large volume Cs2LiYCl6 (CLYC) detectors for nuclear security applications. Three-inch diameter boules have been grown and 3-in right cylinders have been fabricated. Crystals containing either >95% 6Li or >99% 7Li have been grown for applications specific to thermal or fast neutron detection, respectively. We evaluated their gamma and neutron detection properties and the performance is as good as small size crystals. Gamma and neutron efficiencies were measured for large crystals and compared with smaller size crystals. With their excellent performance characteristics, and the ability to detect fast neutrons, CLYC detectors are excellent triple-mode scintillators for use in handheld and backpack instruments for nuclear security applications.

Mo 99 Draft Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seestrom, Susan Joyce

The Nuclear Science Advisory Committee (NSAC) 99Molybdenum ( 99Mo) Subcommittee met December 14-15, 2017 to address the charge to NSAC requesting that a fourth annual review of the National Nuclear Security Administration (NNSA) 99Mo program be performed. The Subcommittee found that the NNSA has continued to make progress over the course of the year based on the specific American Medical Isotopes Production Act of 2012 (AMIPA) requirements.

Nuclear Cryogenic Propulsion Stage

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

2012-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

Adrenocortical nuclear progesterone-binding protein: Identification by photoaffinity labeling and evidence for deoxyribonucleic acid binding and stimulation by adrenocorticotropin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demura, T.; Driscoll, W.J.; Lee, Y.C.

1991-01-01

Nuclei of the guinea pig adrenal cortex contain a protein that specifically binds progesterone and that, biochemically, is clearly distinct from the classical progesterone receptor. The adrenocortical nuclear progesterone-binding protein has now been purified more than 2000-fold by steroid-affinity chromatography with a 75% yield. The purified protein preparation demonstrated three major bands on sodium dodecyl sulfate-polyacrylamide gel of 79K, 74K, and 50K. To determine which of the three might represent the progesterone-binding protein, steroid photoaffinity labeling was performed which resulted in the specific and exclusive labeling of a 50K band. Thus, the adrenocortical nuclear progesterone-binding protein appears to be distinctmore » from the classical progesterone receptor not only biochemically, but also on the basis of molecular size. To test whether the adrenocortical nuclear progesterone-binding protein can be hormonally stimulated, guinea pigs were treated with ACTH. The chronic administration of ACTH caused a 4- to 6-fold increase in the specific progesterone binding capacity without a change in the binding affinity. There appeared to be no significant difference in nuclear progesterone binding between the zona fasciculata and zona reticularis. This finding suggests a mediating role for the progesterone-binding protein in ACTH action. In addition, the nuclear progesterone-binding protein bound to nonspecific DNA sequences, further suggesting a possible transcriptional regulatory role.« less

Instant release fraction corrosion studies of commercial UO2 BWR spent nuclear fuel

NASA Astrophysics Data System (ADS)

Martínez-Torrents, Albert; Serrano-Purroy, Daniel; Sureda, Rosa; Casas, Ignasi; de Pablo, Joan

2017-05-01

The instant release fraction of a spent nuclear fuel is a matter of concern in the performance assessment of a deep geological repository since it increases the radiological risk. Corrosion studies of two different spent nuclear fuels were performed using bicarbonate water under oxidizing conditions to study their instant release fraction. From each fuel, cladded segments and powder samples obtained at different radial positions were used. The results were normalised using the specific surface area to permit a comparison between fuels and samples. Different radionuclide dissolution patterns were studied in terms of water contact availability and radial distribution in the spent nuclear fuel. The relationship between the results of this work and morphological parameters like the grain size or irradiation parameters such as the burn-up or the linear power density was studied in order to increase the understanding of the instant release fraction formation.

Radiation pager

NASA Astrophysics Data System (ADS)

Warren, John L.; Vadnais, Kenneth G.

1997-01-01

Recent advances in miniature photomultiplier tubes and low power electronics have made possible a new generation of small gamma-ray radiation detectors specifically designed for use by government and law enforcement agencies for the detection and interdiction of concealed nuclear materials. This paper describes an inexpensive pager sized radiation detector that can be worn on the belt or carried in a pocket for hands free operation, and which can quietly alert the operator to the presence of nuclear material. The sensitivity performance of the detector technology and the application of the instrument to law enforcement and nuclear smuggling are discussed.

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

NASA Technical Reports Server (NTRS)

Jacobson, David T.; Manzella, David H.

2004-01-01

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

A cermet fuel reactor for nuclear thermal propulsion

NASA Technical Reports Server (NTRS)

Kruger, Gordon

1991-01-01

Work on the cermet fuel reactor done in the 1960's by General Electric (GE) and the Argonne National Laboratory (ANL) that had as its goal the development of systems that could be used for nuclear rocket propulsion as well as closed cycle propulsion system designs for ship propulsion, space nuclear propulsion, and other propulsion systems is reviewed. It is concluded that the work done in the 1960's has demonstrated that we can have excellent thermal and mechanical performance with cermet fuel. Thousands of hours of testing were performed on the cermet fuel at both GE and AGL, including very rapid transients and some radiation performance history. We conclude that there are no feasibility issues with cermet fuel. What is needed is reactivation of existing technology and qualification testing of a specific fuel form. We believe this can be done with a minimum development risk.

Progress in space nuclear reactor power systems technology development - The SP-100 program

NASA Technical Reports Server (NTRS)

Davis, H. S.

1984-01-01

Activities related to the development of high-temperature compact nuclear reactors for space applications had reached a comparatively high level in the U.S. during the mid-1950s and 1960s, although only one U.S. nuclear reactor-powered spacecraft was actually launched. After 1973, very little effort was devoted to space nuclear reactor and propulsion systems. In February 1983, significant activities toward the development of the technology for space nuclear reactor power systems were resumed with the SP-100 Program. Specific SP-100 Program objectives are partly related to the determination of the potential performance limits for space nuclear power systems in 100-kWe and 1- to 100-MW electrical classes. Attention is given to potential missions and applications, regimes of possible space power applicability, safety considerations, conceptual system designs, the establishment of technical feasibility, nuclear technology, materials technology, and prospects for the future.

Nuclear electric propulsion mission performance for fast piloted Mars missions

NASA Technical Reports Server (NTRS)

Hack, K. J.; George, J. A.; Dudzinski, L. A.

1991-01-01

A mission study aimed at minimizing the time humans would spend in the space environment is presented. The use of nuclear electric propulsion (NEP), when combined with a suitable mission profile, can reduce the trip time to durations competitive with other propulsion systems. Specifically, a split mission profile utilizing an earth crew capture vehicle accounts for a significant portion of the trip time reduction compared to previous studies. NEP is shown to be capable of performing fast piloted missions to Mars at low power levels using near-term technology and is considered to be a viable candidate for these missions.

Commercial grade item (CGI) dedication of generators for nuclear safety related applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, R.K.; Hajos, L.G.

1993-03-01

The number of nuclear safety related equipment suppliers and the availability of spare and replacement parts designed specifically for nuclear safety related application are shrinking rapidly. These have made it necessary for utilities to apply commercial grade spare and replacement parts in nuclear safety related applications after implementing proper acceptance and dedication process to verify that such items conform with the requirements of their use in nuclear safety related application. The general guidelines for the commercial grade item (CGI) acceptance and dedication are provided in US Nuclear Regulatory Commission (NRC) Generic Letters and Electric Power Research Institute (EPRI) Report NP-5652,more » Guideline for the Utilization of Commercial Grade Items in Nuclear Safety Related Applications. This paper presents an application of these generic guidelines for procurement, acceptance, and dedication of a commercial grade generator for use as a standby generator at Salem Generating Station Units 1 and 2. The paper identifies the critical characteristics of the generator which once verified, will provide reasonable assurance that the generator will perform its intended safety function. The paper also delineates the method of verification of the critical characteristics through tests and provide acceptance criteria for the test results. The methodology presented in this paper may be used as specific guidelines for reliable and cost effective procurement and dedication of commercial grade generators for use as standby generators at nuclear power plants.« less

Evaluation of High-Performance Space Nuclear Electric Generators for Electric Propulsion Application

NASA Technical Reports Server (NTRS)

Woodcock, Gordon; Kross, Dennis A. (Technical Monitor)

2002-01-01

Electric propulsion applications are enhanced by high power-to-mass ratios for their electric power sources. At multi-megawatt levels, we can expect thrust production systems to be less than 5 kg/kWe. Application of nuclear electric propulsion to human Mars missions becomes an attractive alternative to nuclear thermal propulsion if the propulsion system is less than about 10 kg/kWe. Recent references have projected megawatt-plus nuclear electric sources at specific mass values from less than 1 kg/kWe to about 5 kg/kWe. Various assumptions are made regarding power generation cycle (turbogenerator; MHD (magnetohydrodynamics)) and reactor heat source design. The present paper compares heat source and power generation options on the basis of a parametric model that emphasizes heat transfer design and realizable hardware concept. Pressure drop (important!) is included in the power cycle analysis, and MHD and turbogenerator cycles are compared. Results indicate that power source specific mass less than 5 kg/kWe is attainable, even if peak temperatures achievable are limited to 1500 K. Projections of specific mass less than 1 kg/kWe are unrealistic, even at the highest peak temperatures considered.

The NASA Advanced Exploration Systems Nuclear Thermal Propulsion Project

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Mitchell, Doyce P.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Clement, Steven; Borowski, Stanley K.;

Hydrogen Production from Nuclear Energy via High Temperature Electrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

James E. O'Brien; Carl M. Stoots; J. Stephen Herring

2006-04-01

This paper presents the technical case for high-temperature nuclear hydrogen production. A general thermodynamic analysis of hydrogen production based on high-temperature thermal water splitting processes is presented. Specific details of hydrogen production based on high-temperature electrolysis are also provided, including results of recent experiments performed at the Idaho National Laboratory. Based on these results, high-temperature electrolysis appears to be a promising technology for efficient large-scale hydrogen production.

Preparation of isolated nuclei from K 562 haemopoietic cell line for high resolution scanning electron microscopy.

PubMed

Reipert, S; Reipert, B M; Allen, T D

1994-09-01

The aim of the work is to visualise nuclear pore complexes (NPCs) in mammalian cells by high resolution scanning electron microscopy. A detergent-free isolation protocol was employed to obtain clean nuclei from the haemopoietic cell line K 562. Nuclear isolation was performed by mechanical homogenisation under hypotonic conditions followed by purification of the nuclear fraction. The isolated nuclei were attached to silicon chips, fixed, critical point dried, and sputter coated with a thin film (3-4 nm) of tantalum. Analysis of the nuclear surface by scanning electron microscopy (SEM) revealed a strong sensitivity of the outer nuclear membrane (ONM) to disruption during the isolation procedure. A significant reduction of the characteristic pattern of damage to the ONM was achieved by means of an isopicnic centrifugation on an isoosmolar balanced Percoll gradient. Analysis of the population of isolated nuclei by flow cytometry showed no signs of cell cycle specific losses of nuclei during isolation. The SEM investigations of the morphology of the nuclear envelope (NE) and of substructural details of NPCs and polyribosomes were performed using an in-lens field emission scanning electron microscope.

Quantitative 3D Analysis of Nuclear Morphology and Heterochromatin Organization from Whole-Mount Plant Tissue Using NucleusJ.

PubMed

Desset, Sophie; Poulet, Axel; Tatout, Christophe

2018-01-01

Image analysis is a classical way to study nuclear organization. While nuclear organization used to be investigated by colorimetric or fluorescent labeling of DNA or specific nuclear compartments, new methods in microscopy imaging now enable qualitative and quantitative analyses of chromatin pattern, and nuclear size and shape. Several procedures have been developed to prepare samples in order to collect 3D images for the analysis of spatial chromatin organization, but only few preserve the positional information of the cell within its tissue context. Here, we describe a whole mount tissue preparation procedure coupled to DNA staining using the PicoGreen ® intercalating agent suitable for image analysis of the nucleus in living and fixed tissues. 3D Image analysis is then performed using NucleusJ, an open source ImageJ plugin, which allows for quantifying variations in nuclear morphology such as nuclear volume, sphericity, elongation, and flatness as well as in heterochromatin content and position in respect to the nuclear periphery.

Advances toward fully automated in vivo assessment of oral epithelial dysplasia by nuclear endomicroscopy-A pilot study.

PubMed

Liese, Jan; Winter, Karsten; Glass, Änne; Bertolini, Julia; Kämmerer, Peer Wolfgang; Frerich, Bernhard; Schiefke, Ingolf; Remmerbach, Torsten W

2017-11-01

Uncertainties in detection of oral epithelial dysplasia (OED) frequently result from sampling error especially in inflammatory oral lesions. Endomicroscopy allows non-invasive, "en face" imaging of upper oral epithelium, but parameters of OED are unknown. Mucosal nuclei were imaged in 34 toluidine blue-stained oral lesions with a commercial endomicroscopy. Histopathological diagnosis showed four biopsies in "dys-/neoplastic," 23 in "inflammatory," and seven in "others" disease groups. Strength of different assessment strategies of nuclear scoring, nuclear count, and automated nuclear analysis were measured by area under ROC curve (AUC) to identify histopathological "dys-/neoplastic" group. Nuclear objects from automated image analysis were visually corrected. Best-performing parameters of nuclear-to-image ratios were the count of large nuclei (AUC=0.986) and 6-nearest neighborhood relation (AUC=0.896), and best parameters of nuclear polymorphism were the count of atypical nuclei (AUC=0.996) and compactness of nuclei (AUC=0.922). Excluding low-grade OED, nuclear scoring and count reached 100% sensitivity and 98% specificity for detection of dys-/neoplastic lesions. In automated analysis, combination of parameters enhanced diagnostic strength. Sensitivity of 100% and specificity of 87% were seen for distances of 6-nearest neighbors and aspect ratios even in uncorrected objects. Correction improved measures of nuclear polymorphism only. The hue of background color was stronger than nuclear density (AUC=0.779 vs 0.687) to detect dys-/neoplastic group indicating that macroscopic aspect is biased. Nuclear-to-image ratios are applicable for automated optical in vivo diagnostics for oral potentially malignant disorders. Nuclear endomicroscopy may promote non-invasive, early detection of dys-/neoplastic lesions by reducing sampling error. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Nuclear Cryogenic Propulsion Stage

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

2014-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP). Nuclear propulsion can be affordable and viable compared to other propulsion systems and must overcome a biased public fear due to hyper-environmentalism and a false perception of radiation and explosion risk.

Improved pulse shape discrimination in EJ-301 liquid scintillators

NASA Astrophysics Data System (ADS)

Lang, R. F.; Masson, D.; Pienaar, J.; Röttger, S.

2017-06-01

Digital pulse shape discrimination has become readily available to distinguish nuclear recoil and electronic recoil events in scintillation detectors. We evaluate digital implementations of pulse shape discrimination algorithms discussed in the literature, namely the Charge Comparison Method, Pulse-Gradient Analysis, Fourier Series and Standard Event Fitting. In addition, we present a novel algorithm based on a Laplace Transform. Instead of comparing the performance of these algorithms based on a single Figure of Merit, we evaluate them as a function of recoil energy. Specifically, using commercial EJ-301 liquid scintillators, we examined both the resulting acceptance of nuclear recoils at a given rejection level of electronic recoils, as well as the purity of the selected nuclear recoil event samples. We find that both a Standard Event fit and a Laplace Transform can be used to significantly improve the discrimination capabilities over the whole considered energy range of 0 - 800keVee . Furthermore, we show that the Charge Comparison Method performs poorly in accurately identifying nuclear recoils.

Computerized engineering logic for procurement and dedication processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tulay, M.P.

1996-12-31

This paper summarizes the work performed for designing the system and especially for calculating on-line expected performance and gives some significant results. In an attempt to better meet the needs of operations and maintenance organizations, many nuclear utility procurement engineering groups have simplified their procedures, developed on-line tools for performing the specification of replacement items, and developed relational databases containing part-level information necessary to automate the procurement process. Although these improvements have helped to reduce the engineering necessary to properly specify and accept/dedicate items for nuclear safety-related applications, a number of utilities have recognized that additional long-term savings can bemore » realized by integrating a computerized logic to assist technical procurement engineering personnel.« less

Analytical study of nozzle performance for nuclear thermal rockets

NASA Technical Reports Server (NTRS)

Davidian, Kenneth O.; Kacynski, Kenneth J.

1991-01-01

Nuclear propulsion has been identified as one of the key technologies needed for human exploration of the Moon and Mars. The Nuclear Thermal Rocket (NTR) uses a nuclear reactor to heat hydrogen to a high temperature followed by expansion through a conventional convergent-divergent nozzle. A parametric study of NTR nozzles was performed using the Rocket Engine Design Expert System (REDES) at the NASA Lewis Research Center. The REDES used the JANNAF standard rigorous methodology to determine nozzle performance over a range of chamber temperatures, chamber pressures, thrust levels, and different nozzle configurations. A design condition was set by fixing the propulsion system exit radius at five meters and throat radius was varied to achieve a target thrust level. An adiabatic wall was assumed for the nozzle, and its length was assumed to be 80 percent of a 15 degree cone. The results conclude that although the performance of the NTR, based on infinite reaction rates, looks promising at low chamber pressures, finite rate chemical reactions will cause the actual performance to be considerably lower. Parameters which have a major influence on the delivered specific impulse value include the chamber temperature and the chamber pressures in the high thrust domain. Other parameters, such as 2-D and boundary layer effects, kinetic rates, and number of nozzles, affect the deliverable performance of an NTR nozzle to a lesser degree. For a single nozzle, maximum performance of 930 seconds and 1030 seconds occur at chamber temperatures of 2700 and 3100 K, respectively.

Editorial Note

NASA Astrophysics Data System (ADS)

Degueldre, Claude; Gomez Briceño, Dolores; Fanghänel, Thomas; Warin, Dominique

2006-06-01

These proceedings provide papers that were presented at the Symposium N 'Nuclear Materials' of the EMRS Spring meeting 05, held from May 31 to June 2, 2005 at the Palais des Congrés in Strasbourg. The Symposium concerned materials that are applied in the nuclear environment and that are studied for their specific utilisation under demanding temperature, pressure and irradiation environments. Most of these materials act as barrier and their structural properties are investigated with emphasis on mechanical performances, reliability and long-term behaviour.

Metrics for the technical performance evaluation of light water reactor accident-tolerant fuel

DOE PAGES

Bragg-Sitton, Shannon M.; Todosow, Michael; Montgomery, Robert; ...

2017-03-26

The safe, reliable, and economic operation of the nation’s nuclear power reactor fleet has always been a top priority for the nuclear industry. Continual improvement of technology, including advanced materials and nuclear fuels, remains central to the industry’s success. Enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion following the 2011 Great East Japan Earthquake, resulting tsunami, and subsequent damage to the Fukushima Daiichi nuclear power plant complex. The overall goal for the development of accident-tolerant fuel (ATF) for LWRs is to identify alternative fuel system technologies to further enhance the safety, competitiveness, andmore » economics of commercial nuclear power. Designed for use in the current fleet of commercial LWRs or in reactor concepts with design certifications (GEN-III+), fuels with enhanced accident tolerance would endure loss of active cooling in the reactor core for a considerably longer period of time than the current fuel system while maintaining or improving performance during normal operations. The complex multiphysics behavior of LWR nuclear fuel in the integrated reactor system makes defining specific material or design improvements difficult; as such, establishing desirable performance attributes is critical in guiding the design and development of fuels and cladding with enhanced accident tolerance. Research and development of ATF in the United States is conducted under the U.S. Department of Energy (DOE) Fuel Cycle Research and Development Advanced Fuels Campaign. The DOE is sponsoring multiple teams to develop ATF concepts within multiple national laboratories, universities, and the nuclear industry. Concepts under investigation offer both evolutionary and revolutionary changes to the current nuclear fuel system. This study summarizes the technical evaluation methodology proposed in the United States to aid in the optimization and prioritization of candidate ATF designs.« less

Mobile robotics application in the nuclear industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, S.L.; White, J.R.

1995-03-01

Mobile robots have been developed to perform hazardous operations in place of human workers. Applications include nuclear plant inspection/maintenance, decontamination and decommissioning police/military explosive ordinance disposal (EOD), hostage/terrorist negotiations and fire fighting. Nuclear facilities have proven that robotic applications can be cost-effective solutions to reducing personnel exposure and plant downtime. The first applications of mobile robots in the nuclear industry began in the early 1980`s, with the first vehicles being one of a kind machines or adaptations of commercial EOD robots. These activities included efforts by numerous commercial companies, the U.S. Nuclear Regulatory Commission, EPRI, and several national laboratories. Somemore » of these efforts were driven by the recovery and cleanup activities at TMI which demonstrated the potential and need for a remote means of performing surveillance and maintenance tasks in nuclear plants. The use of these machines is now becoming commonplace in nuclear facilities throughout the world. The hardware maturity and the confidence of the users has progressed to the point where the applications of mobile robots is not longer considered a novelty. These machines are being used in applications where the result is to help achieve more aggressive goals for personnel radiation exposure and plant availability, perform tasks more efficiently, and allow plant operators to retrieve information from areas previously considered inaccessible. Typical examples include surveillance in high radiation areas (during operation and outage activities), radiation surveys, waste handling, and decontamination evolutions. This paper will discuss this evolution including specific applications experiences, examples of currently available technology, and the benefits derived from the use of mobile robotic vehicles in commercial nuclear power facilities.« less

Nuclear Thermal Propulsion Mars Mission Systems Analysis and Requirements Definition

NASA Technical Reports Server (NTRS)

Mulqueen, Jack; Chiroux, Robert C.; Thomas, Dan; Crane, Tracie

2007-01-01

This paper describes the Mars transportation vehicle design concepts developed by the Marshall Space Flight Center (MSFC) Advanced Concepts Office. These vehicle design concepts provide an indication of the most demanding and least demanding potential requirements for nuclear thermal propulsion systems for human Mars exploration missions from years 2025 to 2035. Vehicle concept options vary from large "all-up" vehicle configurations that would transport all of the elements for a Mars mission on one vehicle. to "split" mission vehicle configurations that would consist of separate smaller vehicles that would transport cargo elements and human crew elements to Mars separately. Parametric trades and sensitivity studies show NTP stage and engine design options that provide the best balanced set of metrics based on safety, reliability, performance, cost and mission objectives. Trade studies include the sensitivity of vehicle performance to nuclear engine characteristics such as thrust, specific impulse and nuclear reactor type. Tbe associated system requirements are aligned with the NASA Exploration Systems Mission Directorate (ESMD) Reference Mars mission as described in the Explorations Systems Architecture Study (ESAS) report. The focused trade studies include a detailed analysis of nuclear engine radiation shield requirements for human missions and analysis of nuclear thermal engine design options for the ESAS reference mission.

Colloid formation during waste form reaction: Implications for nuclear waste disposal

USGS Publications Warehouse

Bates, J. K.; Bradley, J.; Teetsov, A.; Bradley, C. R.; Buchholtz ten Brink, Marilyn R.

1992-01-01

Insoluble plutonium- and americium-bearing colloidal particles formed during simulated weathering of a high-level nuclear waste glass. Nearly 100 percent of the total plutonium and americium in test ground water was concentrated in these submicrometer particles. These results indicate that models of actinide mobility and repository integrity, which assume complete solubility of actinides in ground water, underestimate the potential for radionuclide release into the environment. A colloid-trapping mechanism may be necessary for a waste repository to meet long-term performance specifications.

Safety evaluation report on Tennessee Valley Authority: Browns Ferry Nuclear Performance Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-01-01

This safety evaluation report (SER) was prepared by the US Nuclear Regulatory Commission (NRC) staff and represents the second and last supplement (SSER 2) to the staff's original SER published as Volume 3 of NUREG-1232 in April 1989. Supplement 1 of Volume 3 of NUREG-1232 (SSER 1) was published in October 1989. Like its predecessors, SSER 2 is composed of numerous safety evaluations by the staff regarding specific elements contained in the Browns Ferry Nuclear Performance Plan (BFNPP), Volume 3 (up to and including Revision 2), submitted by the Tennessee Valley Authority (TVA) for the Browns Ferry Nuclear Plant (BFN).more » The Browns Ferry Nuclear Plant consists of three boiling-water reactors (BWRs) at a site in Limestone County, Alabama. The BFNPP describes the corrective action plans and commitments made by TVA to resolve deficiencies with its nuclear programs before the startup of Unit 2. The staff has inspected and will continue to inspect TVA's implementation of these BFNPP corrective action plans that address staff concerns about TVA's nuclear program. SSER 2 documents the NRC staff's safety evaluations and conclusions for those elements of the BFNPP that were not previously addressed by the staff or that remained open as a result of unresolved issues identified by the staff in previous SERs and inspections.« less

Analysis of space reactor system components: Investigation through simulation and non-nuclear testing

NASA Astrophysics Data System (ADS)

Bragg-Sitton, Shannon M.

The use of fission energy in space power and propulsion systems offers considerable advantages over chemical propulsion. Fission provides over six orders of magnitude higher energy density, which translates to higher vehicle specific impulse and lower specific mass. These characteristics enable ambitious space exploration missions. The natural space radiation environment provides an external source of protons and high energy, high Z particles that can result in the production of secondary neutrons through interactions in reactor structures. Applying the approximate proton source in geosynchronous orbit during a solar particle event, investigation using MCNPX 2.5.b for proton transport through the SAFE-400 heat pipe cooled reactor indicates an incoming secondary neutron current of (1.16 +/- 0.03) x 107 n/s at the core-reflector interface. This neutron current may affect reactor operation during low power maneuvers (e.g., start-up) and may provide a sufficient reactor start-up source. It is important that a reactor control system be designed to automatically adjust to changes in reactor power levels, maintaining nominal operation without user intervention. A robust, autonomous control system is developed and analyzed for application during reactor start-up, accounting for fluctuations in the radiation environment that result from changes in vehicle location or to temporal variations in the radiation field. Development of a nuclear reactor for space applications requires a significant amount of testing prior to deployment of a flight unit. High confidence in fission system performance can be obtained through relatively inexpensive non-nuclear tests performed in relevant environments, with the heat from nuclear fission simulated using electric resistance heaters. A series of non-nuclear experiments was performed to characterize various aspects of reactor operation. This work includes measurement of reactor core deformation due to material thermal expansion and implementation of a virtual reactivity feedback control loop; testing and thermal hydraulic characterization of the coolant flow paths for two space reactor concepts; and analysis of heat pipe operation during start-up and steady state operation.

Tissue specificity of the hormonal response in sex accessory tissues is associated with nuclear matrix protein patterns.

PubMed

Getzenberg, R H; Coffey, D S

1990-09-01

The DNA of interphase nuclei have very specific three-dimensional organizations that are different in different cell types, and it is possible that this varying DNA organization is responsible for the tissue specificity of gene expression. The nuclear matrix organizes the three-dimensional structure of the DNA and is believed to be involved in the control of gene expression. This study compares the nuclear structural proteins between two sex accessory tissues in the same animal responding to the same androgen stimulation by the differential expression of major tissue-specific secretory proteins. We demonstrate here that the nuclear matrix is tissue specific in the rat ventral prostate and seminal vesicle, and undergoes characteristic alterations in its protein composition upon androgen withdrawal. Three types of nuclear matrix proteins were observed: 1) nuclear matrix proteins that are different and tissue specific in the rat ventral prostate and seminal vesicle, 2) a set of nuclear matrix proteins that either appear or disappear upon androgen withdrawal, and 3) a set of proteins that are common to both the ventral prostate and seminal vesicle and do not change with the hormonal state of the animal. Since the nuclear matrix is known to bind androgen receptors in a tissue- and steroid-specific manner, we propose that the tissue specificity of the nuclear matrix arranges the DNA in a unique conformation, which may be involved in the specific interaction of transcription factors with DNA sequences, resulting in tissue-specific patterns of secretory protein expression.

Fuel Aging in Storage and Transportation (FAST): Accelerated Characterization and Performance Assessment of the Used Nuclear Fuel Storage System

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDeavitt, Sean

2016-08-02

This Integrated Research Project (IRP) was established to characterize key limiting phenomena related to the performance of used nuclear fuel (UNF) storage systems. This was an applied engineering project with a specific application in view (i.e., UNF dry storage). The completed tasks made use of a mixture of basic science and engineering methods. The overall objective was to create, or enable the creation of, predictive tools in the form of observation methods, phenomenological models, and databases that will enable the design, installation, and licensing of dry UNF storage systems that will be capable of containing UNF for extended period ofmore » time.« less

Four nucleocytoplasmic-shuttling proteins and p53 interact specifically with the YB-NLS and are involved in anticancer reagent-induced nuclear localization of YB-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Toru; Ohashi, Sachiyo; Kobayashi, Shunsuke

In cancer cells, anticancer reagents often trigger nuclear accumulation of YB-1, which participates in the progression of cancer malignancy. YB-1 has a non-canonical nuclear localization signal (YB-NLS). Here we found that four nucleocytoplasmic-shuttling RNA-binding proteins and p53 interact specifically with the YB-NLS and co-accumulate with YB-1 in the nucleus of actinomycin D-treated cells. To elucidate the roles of these YB-NLS-binding proteins, we performed a dominant-negative experiment in which a large excess of YB-NLS interacts with the YB-NLS-binding proteins, and showed inhibitory effects on actinomycin D-induced nuclear transport of endogenous YB-1 and subsequent MDR1 gene expression. Furthermore, the YB-NLS-expressing cells weremore » also found to show increased drug sensitivity. Our results suggest that these YB-NLS-associating proteins are key factors for nuclear translocation/accumulation of YB-1 in cancer cells. - Highlights: • Four nucleocytoplasmic-shuttling proteins and p53 associate with YB-NLS. • They showed nuclear co-accumulation with YB-1 in actinomycin D-treated cells. • Overexpression of YB-NLS was carried out to take YB-NLS-binding proteins from YB-1. • YB-NLS inhibited actinomycin D-induced nuclear localization of endogenous YB-1. • YB-NLS suppressed actinomycin D-induced expression of MDR1.« less

Advanced instrumentation and analysis methods for in-pile thermal and nuclear measurements: from out-of-pile studies to irradiation campaigns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynard-Carette, C.; Lyoussi, A.

Research and development on nuclear fuel behavior under irradiations and accelerated ageing of structure materials is a key issue for sustainable nuclear energy in order to meet specific needs by keeping the best level of safety. A new Material Testing Reactor (MTR), the Jules Horowitz Reactor (JHR) currently under construction in the South of France in the CEA Cadarache research centre will offer a real opportunity to perform R and D programs and hence will crucially contribute to the selection, optimization and qualification of innovative materials and fuels. To perform such programs advanced accurate and innovative experiments, irradiation devices thatmore » contain material and fuel samples are required to be set up inside or beside the reactor core. These experiments needs beforehand in situ and on line sophisticated measurements to accurately reach specific and determining parameters such as thermal and fast neutron fluxes, nuclear heating and temperature conditions to precisely monitor and control the conducted assays. Consequently, since 2009 CEA and Aix-Marseille University collaborate in order to design and develop a new multi-sensor device which will be dedicated to measuring profiles of such conditions inside the experimental channels of the JHR. These works are performed in the framework of two complementary joint research programs called MAHRI-BETHY and INCORE. These programs couple experimental studies carried out both out-of nuclear fluxes (in laboratory) and under irradiation conditions (in OSIRIS MTR reactor in France and MARIA MTR reactor in Poland) with numerical works realized by thermal simulations (CAST3M code) and Monte Carlo simulations (MCNP code). These programs deal with three main aims. The first one corresponds to the design and/or the test of new in-pile instrumentation. The second one concerns the development of advanced calibration procedures in particular in the case of one specific sensor: a differential calorimeter used to quantify nuclear heating. The last one consists in the development of accurate measurement and analysis methods. The paper will be dedicated to a complete review of the experimental and numerical works performed since 2009 thanks to two parts. The first part will detail a new thermal approach implemented to improve nuclear heating measurements by radiometric calorimeters. New experimental tools (calorimeter prototypes and set-ups such BETHY Bench) developed to perform preliminary out-of-pile studies under suitable conditions will be presented (temperature and velocity of the external cooling fluid, heat source localization and intensity inside the calorimetric cells). Then the response of two kinds of sensors, their calibrations curves and their thermal behaviors will be compared for various parameters. Finally validated numerical thermal and Monte Carlo works will be discussed to propose new improvements. The second parts of the paper will focus on works realized in order to design, develop and test the first prototype of the multi-sensor device called CARMEN [7-9]. The two mock-ups dedicated respectively to neutron measurements and photon measurements will be detailed. The results obtained during two irradiation campaigns inside the periphery of OSIRIS reactor will be shown. The new analysis method will be discussed. (authors)« less

Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis

NASA Technical Reports Server (NTRS)

Wang, Ten-See

2005-01-01

The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

Protein synthesis and the recovery of both survival and cytoplasmic "petite" mutation in ultraviolet-treated yeast cells. I. Nuclear-directed protein synthesis.

PubMed

Heude, M; Chanet, R; Moustacchi, E

1975-04-01

The contribution of nuclear-directed protein synthesis in the repair of lethal and mitochondrial genetic damage after UV-irradiation of exponential and stationary phage haploid yeast cells was examined. This was carried out using cycloheximide (CH), a specific inhibitor of nuclear protein synthesis. It appears that nuclear protein synthesis is required for the increase in survival seen after the liquid holding of cells at both stages, as well as for the "petite" recovery seen after the liquid holding of exponential phase cells. The characteristic negative liquid holding effect observed for the UV induction of "petites" in stationary phase cells (increase of the frequency of "petites" during storage) remained following all the treatments which inhibited nuclear protein synthesis. However, the application of photoreactivating light following dark holding with cycloheximide indicates that some steps of the repair of both nuclear and mitochondrial damage are performed in the absence of a synthesis of proteins.

Modeling and Testing of Non-Nuclear, Highpower Simulated Nuclear Thermal Rocket Reactor Elements

NASA Technical Reports Server (NTRS)

Kirk, Daniel R.

2005-01-01

When the President offered his new vision for space exploration in January of 2004, he said, "Our third goal is to return to the moon by 2020, as the launching point for missions beyond," and, "With the experience and knowledge gained on the moon, we will then be ready to take the next steps of space exploration: human missions to Mars and to worlds beyond." A human mission to Mars implies the need to move large payloads as rapidly as possible, in an efficient and cost-effective manner. Furthermore, with the scientific advancements possible with Project Prometheus and its Jupiter Icy Moons Orbiter (JIMO), (these use electric propulsion), there is a renewed interest in deep space exploration propulsion systems. According to many mission analyses, nuclear thermal propulsion (NTP), with its relatively high thrust and high specific impulse, is a serious candidate for such missions. Nuclear rockets utilize fission energy to heat a reactor core to very high temperatures. Hydrogen gas flowing through the core then becomes superheated and exits the engine at very high exhaust velocities. The combination of temperature and low molecular weight results in an engine with specific impulses above 900 seconds. This is almost twice the performance of the LOX/LH2 space shuttle engines, and the impact of this performance would be to reduce the trip time of a manned Mars mission from the 2.5 years, possible with chemical engines, to about 12-14 months.

Bleed cycle propellant pumping in a gas-core nuclear rocket engine system

NASA Technical Reports Server (NTRS)

Kascak, A. F.; Easley, A. J.

1972-01-01

The performance of ideal and real staged primary propellant pumps and bleed-powered turbines was calculated for gas-core nuclear rocket engines over a range of operating pressures from 500 to 5000 atm. This study showed that for a required engine operating pressure of 1000 atm the pump work was about 0.8 hp/(lb/sec), the specific impulse penalty resulting from the turbine propellant bleed flow as about 10 percent; and the heat required to preheat the propellant was about 7.8 MN/(lb/sec). For a specific impulse above 2400 sec, there is an excess of energy available in the moderator due to the gamma and neutron heating that occurs there. Possible alternative pumping cycles are the Rankine or Brayton cycles.

Fabrication and characterization of joined silicon carbide cylindrical components for nuclear applications

NASA Astrophysics Data System (ADS)

Khalifa, H. E.; Deck, C. P.; Gutierrez, O.; Jacobsen, G. M.; Back, C. A.

2015-02-01

The use of silicon carbide (SiC) composites as structural materials in nuclear applications necessitates the development of a viable joining method. One critical application for nuclear-grade joining is the sealing of fuel within a cylindrical cladding. This paper demonstrates cylindrical joint feasibility using a low activation nuclear-grade joint material comprised entirely of β-SiC. While many papers have considered joining material, this paper takes into consideration the joint geometry and component form factor, as well as the material performance. Work focused specifically on characterizing the strength and permeability performance of joints between cylindrical SiC-SiC composites and monolithic SiC endplugs. The effects of environment and neutron irradiation were not evaluated in this study. Joint test specimens of different geometries were evaluated in their as-fabricated state, as well as after being subjected to thermal cycling and partial mechanical loading. A butted scarf geometry supplied the best combination of high strength and low permeability. A leak rate performance of 2 × 10-9 mbar l s-1 was maintained after thermal cycling and partial mechanical loading and sustained applied force of 3.4 kN, or an apparent strength of 77 MPa. This work shows that a cylindrical SiC-SiC composite tube sealed with a butted scarf endplug provides out-of-pile strength and permeability performance that meets light water reactor design requirements.

The program at JPL to investigate the nuclear interaction of RTG's with scientific instruments on deep space probes

NASA Technical Reports Server (NTRS)

Truscello, V.

1972-01-01

A major concern in the integration of a radioisotope thermoelectric generator (RTG) with a spacecraft designed to explore the outer planets is the effect of the emitted radiation on the normal operation of scientific instruments. The necessary techniques and tools developed to allow accurate calculation of the neutron and gamma spectrum emanating from the RTG. The specific sources of radiation were identified and quantified. Monte Carlo techniques are then employed to perform the nuclear transport calculations. The results of these studies are presented. An extensive experimental program was initiated to measure the response of a number of scientific components to the nuclear radiation.

Upgrading the fuel-handling machine of the Novovoronezh nuclear power plant unit no. 5

NASA Astrophysics Data System (ADS)

Terekhov, D. V.; Dunaev, V. I.

2014-02-01

The calculation of safety parameters was carried out in the process of upgrading the fuel-handling machine (FHM) of the Novovoronezh nuclear power plant (NPP) unit no. 5 based on the results of quantitative safety analysis of nuclear fuel transfer operations using a dynamic logical-and-probabilistic model of the processing procedure. Specific engineering and design concepts that made it possible to reduce the probability of damaging the fuel assemblies (FAs) when performing various technological operations by an order of magnitude and introduce more flexible algorithms into the modernized FHM control system were developed. The results of pilot operation during two refueling campaigns prove that the total reactor shutdown time is lowered.

10 CFR 50.36a - Technical specifications on effluents from nuclear power reactors.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Technical specifications on effluents from nuclear power reactors. 50.36a Section 50.36a Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND...; Ineligibility of Certain Applicants § 50.36a Technical specifications on effluents from nuclear power reactors...

10 CFR 50.36a - Technical specifications on effluents from nuclear power reactors.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Technical specifications on effluents from nuclear power reactors. 50.36a Section 50.36a Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND...; Ineligibility of Certain Applicants § 50.36a Technical specifications on effluents from nuclear power reactors...

Identification of Androgen Receptor-Specific Enhancer RNAs

DTIC Science & Technology

2016-06-01

Release; Distribution Unlimited The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as...There are two Tasks in this application. First, we will perform global run-on assay and deep sequencing to identify AR -specific enhancer RNAs. Second...1 Introduction The androgen receptor ( AR ) is a nuclear receptor transcription factor required for normal prostate development and prostate

Material Stream Strategy for Lithium and Inorganics (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safarik, Douglas Joseph; Dunn, Paul Stanton; Korzekwa, Deniece Rochelle

Design Agency Responsibilities: Manufacturing Support to meet Stockpile Stewardship goals for maintaining the nuclear stockpile through experimental and predictive modeling capability. Development and maintenance of Manufacturing Science expertise to assess material specifications and performance boundaries, and their relationship to processing parameters. Production Engineering Evaluations with competence in design requirements, material specifications, and manufacturing controls. Maintenance and enhancement of Aging Science expertise to support Stockpile Stewardship predictive science capability.

Nuclear Thermal Rocket Simulation in NPSS

NASA Technical Reports Server (NTRS)

Belair, Michael L.; Sarmiento, Charles J.; Lavelle, Thomas M.

2013-01-01

Four nuclear thermal rocket (NTR) models have been created in the Numerical Propulsion System Simulation (NPSS) framework. The models are divided into two categories. One set is based upon the ZrC-graphite composite fuel element and tie tube-style reactor developed during the Nuclear Engine for Rocket Vehicle Application (NERVA) project in the late 1960s and early 1970s. The other reactor set is based upon a W-UO2 ceramic-metallic (CERMET) fuel element. Within each category, a small and a large thrust engine are modeled. The small engine models utilize RL-10 turbomachinery performance maps and have a thrust of approximately 33.4 kN (7,500 lbf ). The large engine models utilize scaled RL-60 turbomachinery performance maps and have a thrust of approximately 111.2 kN (25,000 lbf ). Power deposition profiles for each reactor were obtained from a detailed Monte Carlo N-Particle (MCNP5) model of the reactor cores. Performance factors such as thermodynamic state points, thrust, specific impulse, reactor power level, and maximum fuel temperature are analyzed for each engine design.

Nuclear Thermal Rocket Simulation in NPSS

NASA Technical Reports Server (NTRS)

Belair, Michael L.; Sarmiento, Charles J.; Lavelle, Thomas L.

2013-01-01

Four nuclear thermal rocket (NTR) models have been created in the Numerical Propulsion System Simulation (NPSS) framework. The models are divided into two categories. One set is based upon the ZrC-graphite composite fuel element and tie tube-style reactor developed during the Nuclear Engine for Rocket Vehicle Application (NERVA) project in the late 1960s and early 1970s. The other reactor set is based upon a W-UO2 ceramic- metallic (CERMET) fuel element. Within each category, a small and a large thrust engine are modeled. The small engine models utilize RL-10 turbomachinery performance maps and have a thrust of approximately 33.4 kN (7,500 lbf ). The large engine models utilize scaled RL-60 turbomachinery performance maps and have a thrust of approximately 111.2 kN (25,000 lbf ). Power deposition profiles for each reactor were obtained from a detailed Monte Carlo N-Particle (MCNP5) model of the reactor cores. Performance factors such as thermodynamic state points, thrust, specific impulse, reactor power level, and maximum fuel temperature are analyzed for each engine design.

CESAR robotics and intelligent systems research for nuclear environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mann, R.C.

1992-07-01

The Center for Engineering Systems Advanced Research (CESAR) at the Oak Ridge National Laboratory (ORNL) encompasses expertise and facilities to perform basic and applied research in robotics and intelligent systems in order to address a broad spectrum of problems related to nuclear and other environments. For nuclear environments, research focus is derived from applications in advanced nuclear power stations, and in environmental restoration and waste management. Several programs at CESAR emphasize the cross-cutting technology issues, and are executed in appropriate cooperation with projects that address specific problem areas. Although the main thrust of the CESAR long-term research is on developingmore » highly automated systems that can cooperate and function reliably in complex environments, the development of advanced human-machine interfaces represents a significant part of our research. 11 refs.« less

CESAR robotics and intelligent systems research for nuclear environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mann, R.C.

1992-01-01

The Center for Engineering Systems Advanced Research (CESAR) at the Oak Ridge National Laboratory (ORNL) encompasses expertise and facilities to perform basic and applied research in robotics and intelligent systems in order to address a broad spectrum of problems related to nuclear and other environments. For nuclear environments, research focus is derived from applications in advanced nuclear power stations, and in environmental restoration and waste management. Several programs at CESAR emphasize the cross-cutting technology issues, and are executed in appropriate cooperation with projects that address specific problem areas. Although the main thrust of the CESAR long-term research is on developingmore » highly automated systems that can cooperate and function reliably in complex environments, the development of advanced human-machine interfaces represents a significant part of our research. 11 refs.« less

Milestones for Selection, Characterization, and Analysis of the Performance of a Repository for Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rechard, Robert P.

This report presents a concise history in tabular form of events leading up to site identification in 1978, site selection in 1987, subsequent characterization, and ongoing analysis through 2008 of the performance of a repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain in southern Nevada. The tabulated events generally occurred in five periods: (1) commitment to mined geologic disposal and identification of sites; (2) site selection and analysis, based on regional geologic characterization through literature and analogous data; (3) feasibility analysis demonstrating calculation procedures and importance of system components, based on rough measures of performance usingmore » surface exploration, waste process knowledge, and general laboratory experiments; (4) suitability analysis demonstrating viability of disposal system, based on environment-specific laboratory experiments, in-situ experiments, and underground disposal system characterization; and (5) compliance analysis, based on completed site-specific characterization. Because the relationship is important to understanding the evolution of the Yucca Mountain Project, the tabulation also shows the interaction between four broad categories of political bodies and government agencies/institutions: (a) technical milestones of the implementing institutions, (b) development of the regulatory requirements and related federal policy in laws and court decisions, (c) Presidential and agency directives and decisions, and (d) critiques of the Yucca Mountain Project and pertinent national and world events related to nuclear energy and radioactive waste.« less

Predictions of dispersion and deposition of fallout from nuclear testing using the NOAA-HYSPLIT meteorological model.

PubMed

Moroz, Brian E; Beck, Harold L; Bouville, André; Simon, Steven L

2010-08-01

The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly where little historical fallout monitoring data are available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particle sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that, when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of simulations of the deposition of fallout from atmospheric nuclear tests conducted in the Marshall Islands (mid-Pacific), at the Nevada Test Site (U.S.), and at the Semipalatinsk Nuclear Test Site (Kazakhstan) were performed. The results of the Marshall Islands simulations were used in a limited fashion to support the dose reconstruction described in companion papers within this volume.

PREDICTIONS OF DISPERSION AND DEPOSITION OF FALLOUT FROM NUCLEAR TESTING USING THE NOAA-HYSPLIT METEOROLOGICAL MODEL

PubMed Central

Moroz, Brian E.; Beck, Harold L.; Bouville, André; Simon, Steven L.

2013-01-01

The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly, where little historical fallout monitoring data is available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particles sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of simulations of the deposition of fallout from atmospheric nuclear tests conducted in the Marshall Islands, at the Nevada Test Site (USA), and at the Semipalatinsk Nuclear Test Site (Kazakhstan) were performed using reanalysis data composed of historic meteorological observations. The results of the Marshall Islands simulations were used in a limited fashion to support the dose reconstruction described in companion papers within this volume. PMID:20622555

Enhanced forensic discrimination of pollutants by position-specific isotope analysis using isotope ratio monitoring by (13)C nuclear magnetic resonance spectrometry.

PubMed

Julien, Maxime; Nun, Pierrick; Höhener, Patrick; Parinet, Julien; Robins, Richard J; Remaud, Gérald S

2016-01-15

In forensic environmental investigations the main issue concerns the inference of the original source of the pollutant for determining the liable party. Isotope measurements in geochemistry, combined with complimentary techniques for contaminant identification, have contributed significantly to source determination at polluted sites. In this work we have determined the intramolecular (13)C profiles of several molecules well-known as pollutants. By giving additional analytical parameters, position-specific isotope analysis performed by isotope ratio monitoring by (13)C nuclear magnetic resonance (irm-(13)C NMR) spectrometry gives new information to help in answering the major question: what is the origin of the detected contaminant? We have shown that isotope profiling of the core of a molecule reveals both the raw materials and the process used in its manufacture. It also can reveal processes occurring between the contamination site 'source' and the sampling site. Thus, irm-(13)C NMR is shown to be a very good complement to compound-specific isotope analysis currently performed by mass spectrometry for assessing polluted sites involving substantial spills of pollutant. Copyright © 2015 Elsevier B.V. All rights reserved.

Historical patterns in the types of procedures performed and radiation safety practices used in nuclear medicine from 1945–2009

PubMed Central

Van Dyke, Miriam E.; Drozdovitch, Vladimir; Doody, Michele M.; Lim, Hyeyeun; Bolus, Norman E.; Simon, Steven L.; Alexander, Bruce H.; Kitahara, Cari M.

2016-01-01

We evaluated historical patterns in the types of procedures performed in diagnostic and therapeutic nuclear medicine and the associated radiation safety practices used from 1945–2009 in a sample of U.S. radiologic technologists. In 2013–2014, 4,406 participants from the U.S. Radiologic Technologists (USRT) Study who previously reported working with medical radionuclides completed a detailed survey inquiring about the performance of 23 diagnostic and therapeutic radionuclide procedures and the use of radiation safety practices when performing radionuclide procedure-related tasks during five time periods: 1945–1964, 1965–1979, 1980–1989, 1990–1999, and 2000–2009. We observed an overall increase in the proportion of technologists who performed specific diagnostic or therapeutic procedures across the five time periods. Between 1945–1964 and 2000–2009, the median frequency of diagnostic procedures performed substantially increased (5 per week to 30 per week), attributable mainly to an increasing frequency of cardiac and non-brain PET scans, while the median frequency of therapeutic procedures performed modestly decreased (from 4 per month to 3 per month). We also observed a notable increase in the use of most radiation safety practices from 1945–1964 to 2000–2009 (e.g., use of lead-shielded vials during diagnostic radiopharmaceutical preparation increased from 56 to 96%), although lead apron use dramatically decreased (e.g., during diagnostic imaging procedures, from 81 to 7%). These data describe historical practices in nuclear medicine and can be used to support studies of health risks in nuclear medicine technologists. PMID:27218293

Methods of increasing the performance of radionuclide generators used in nuclear medicine: daughter nuclide build-up optimisation, elution-purification-concentration integration, and effective control of radionuclidic purity.

PubMed

Le, Van So; Do, Zoe Phuc-Hien; Le, Minh Khoi; Le, Vicki; Le, Natalie Nha-Truc

2014-06-10

Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of "early elution schedule" was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement certainty with respect to optimising decay/measurement time and product sample activity used for QC quality control. The optimisation ensures a certainty of measurement of the specific impure radionuclide and avoids wasting the useful amount of valuable purified/concentrated daughter nuclide product. This process is important for the spectrometric measurement of very low activity of impure radionuclide contamination in the radioisotope products of much higher activity used in medical imaging and targeted radiotherapy.

A high power ion thruster for deep space missions

NASA Astrophysics Data System (ADS)

Polk, James E.; Goebel, Dan M.; Snyder, John S.; Schneider, Analyn C.; Johnson, Lee K.; Sengupta, Anita

2012-07-01

The Nuclear Electric Xenon Ion System ion thruster was developed for potential outer planet robotic missions using nuclear electric propulsion (NEP). This engine was designed to operate at power levels ranging from 13 to 28 kW at specific impulses of 6000-8500 s and for burn times of up to 10 years. State-of-the-art performance and life assessment tools were used to design the thruster, which featured 57-cm-diameter carbon-carbon composite grids operating at voltages of 3.5-6.5 kV. Preliminary validation of the thruster performance was accomplished with a laboratory model thruster, while in parallel, a flight-like development model (DM) thruster was completed and two DM thrusters fabricated. The first thruster completed full performance testing and a 2000-h wear test. The second successfully completed vibration tests at the full protoflight levels defined for this NEP program and then passed performance validation testing. The thruster design, performance, and the experimental validation of the design tools are discussed in this paper.

A high power ion thruster for deep space missions.

PubMed

Polk, James E; Goebel, Dan M; Snyder, John S; Schneider, Analyn C; Johnson, Lee K; Sengupta, Anita

2012-07-01

The Nuclear Electric Xenon Ion System ion thruster was developed for potential outer planet robotic missions using nuclear electric propulsion (NEP). This engine was designed to operate at power levels ranging from 13 to 28 kW at specific impulses of 6000-8500 s and for burn times of up to 10 years. State-of-the-art performance and life assessment tools were used to design the thruster, which featured 57-cm-diameter carbon-carbon composite grids operating at voltages of 3.5-6.5 kV. Preliminary validation of the thruster performance was accomplished with a laboratory model thruster, while in parallel, a flight-like development model (DM) thruster was completed and two DM thrusters fabricated. The first thruster completed full performance testing and a 2000-h wear test. The second successfully completed vibration tests at the full protoflight levels defined for this NEP program and then passed performance validation testing. The thruster design, performance, and the experimental validation of the design tools are discussed in this paper.

Determination of neutron flux distribution in an Am-Be irradiator using the MCNP.

PubMed

Shtejer-Diaz, K; Zamboni, C B; Zahn, G S; Zevallos-Chávez, J Y

2003-10-01

A neutron irradiator has been assembled at IPEN facilities to perform qualitative-quantitative analysis of many materials using thermal and fast neutrons outside the nuclear reactor premises. To establish the prototype specifications, the neutron flux distribution and the absorbed dose rates were calculated using the MCNP computer code. These theoretical predictions then allow one to discuss the optimum irradiator design and its performance.

Structural materials issues for the next generation fission reactors

NASA Astrophysics Data System (ADS)

Chant, I.; Murty, K. L.

2010-09-01

Generation-IV reactor design concepts envisioned thus far cater to a common goal of providing safer, longer lasting, proliferation-resistant, and economically viable nuclear power plants. The foremost consideration in the successful development and deployment of Gen-W reactor systems is the performance and reliability issues involving structural materials for both in-core and out-of-core applications. The structural materials need to endure much higher temperatures, higher neutron doses, and extremely corrosive environments, which are beyond the experience of the current nuclear power plants. Materials under active consideration for use in different reactor components include various ferritic/martensitic steels, austenitic stainless steels, nickel-base superalloys, ceramics, composites, etc. This article addresses the material requirements for these advanced fission reactor types, specifically addressing structural materials issues depending on the specific application areas.

Solar Electric Propulsion for Mars Exploration

NASA Technical Reports Server (NTRS)

Hack, Kurt J.

1998-01-01

Highly propellant-efficient electric propulsion is being combined with advanced solar power technology to provide a non-nuclear transportation option for the human exploration of Mars. By virtue of its high specific impulse, electric propulsion offers a greater change in spacecraft velocity for each pound of propellant than do conventional chemical rockets. As a result, a mission to Mars based on solar electric propulsion (SEP) would require fewer heavy-lift launches than a traditional all-chemical space propulsion scenario would. Performance, as measured by mass to orbit and trip time, would be comparable to the NASA design reference mission for human Mars exploration, which utilizes nuclear thermal propulsion; but it would avoid the issues surrounding the use of nuclear reactors in space.

Low-Enriched Uranium Nuclear Thermal Propulsion Systems

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Mitchell, Doyce P.; Aschenbrenner, Ken

2017-01-01

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. For example, using NTP for human Mars missions can provide faster transit and/or round trip times for crew; larger mission payloads; off nominal mission opportunities (including wider injection windows); and crew mission abort options not available from other architectures. The use of NTP can also reduce required earth-to-orbit launches, reducing cost and improving ground logistics. In addition to enabling robust human Mars mission architectures, NTP can be used on exploration missions throughout the solar system. A first generation NTP system could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. Progress made under the NTP project could also help enable high performance fission power systems and Nuclear Electric Propulsion (NEP). Guidance, navigation, and control of NTP may have some unique but manageable characteristics.

Nuclear design of a vapor core reactor for space nuclear propulsion

NASA Astrophysics Data System (ADS)

Dugan, Edward T.; Watanabe, Yoichi; Kuras, Stephen A.; Maya, Isaac; Diaz, Nils J.

1993-01-01

Neutronic analysis methodology and results are presented for the nuclear design of a vapor core reactor for space nuclear propulsion. The Nuclear Vapor Thermal Reactor (NVTR) Rocket Engine uses modified NERVA geometry and systems which the solid fuel replaced by uranium tetrafluoride vapor. The NVTR is an intermediate term gas core thermal rocket engine with specific impulse in the range of 1000-1200 seconds; a thrust of 75,000 lbs for a hydrogen flow rate of 30 kg/s; average core exit temperatures of 3100 K to 3400 K; and reactor thermal powers of 1400 to 1800 MW. Initial calculations were performed on epithermal NVTRs using ZrC fuel elements. Studies are now directed at thermal NVTRs that use fuel elements made of C-C composite. The large ZrC-moderated reactors resulted in thrust-to-weight ratios of only 1 to 2; the compact C-C composite systems yield thrust-to-weight ratios of 3 to 5.

First In-Core Simultaneous Measurements of Nuclear Heating and Thermal Neutron Flux Obtained With the Innovative Mobile Calorimeter CALMOS Inside the OSIRIS Reactor

NASA Astrophysics Data System (ADS)

Carcreff, Hubert; Salmon, Laurent; Bubendorff, Jacques; Lepeltier, Valérie

2016-10-01

Nuclear heating inside a MTR reactor has to be known in order to design and run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. The innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70MWth OSIRIS reactor operated by CEA. Thanks to a new type of calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. Calorimeter working modes, measurement procedures, main modeling and experimental results and expected advantages of this new technique have been already presented in previous papers. However, these first in-core measurements were not performed beyond 6 W · g-1, due to an inside temperature limitation imposed by a safety authority requirement. In this paper, we present the first in-core simultaneous measurements of nuclear heating and conventional thermal neutron flux obtained by the CALMOS device at 70 MW nominal reactor power. For the first time, this experimental system was operated in nominal in-core conditions, with nominal neutron flux up to 2.7 1014 n · cm-2 · s-1 and nuclear heating up to 12 W · g-1. After a brief reminder of the calorimetric cell configuration and displacement system specificities, first nuclear heating distributions at nominal power are presented and discussed. In order to reinforce the heating evaluation, a comparison is made between results obtained by the probe calibration coefficient and the zero methods. Thermal neutron flux evaluation from SPND signal processing required a specific TRIPOLI-4 Monte Carlo calculation which has been performed with the precise CALMOS cell geometry. In addition, the Finite Element model for temperatures map prediction inside the calorimetric cell has been upgraded with recent experimental data obtained up to 12 W · g-1. Finally, the experience feedback led us to improvement perspectives. A second device is currently under manufacturing and main technical options are presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunch, Kyle J.; Williams, Laura S.; Jones, Anthony M.

The 2010 ratification of the New START Treaty has been widely regarded as a noteworthy national security achievement for both the Obama administration and the Medvedev-Putin regime, but deeper cuts are envisioned under future arms control regimes. Future verification needs will include monitoring the storage of warhead components and fissile materials and verifying dismantlement of warheads, pits, secondaries, and other materials. From both the diplomatic and technical perspectives, verification under future arms control regimes will pose new challenges. Since acceptable verification technology must protect sensitive design information and attributes, non-nuclear non-sensitive signatures may provide a significant verification tool without themore » use of additional information barriers. The use of electromagnetic signatures to monitor nuclear material storage containers is a promising technology with the potential to fulfill these challenging requirements. Research performed at Pacific Northwest National Laboratory (PNNL) has demonstrated that low frequency electromagnetic signatures of sealed metallic containers can be used to confirm the presence of specific components on a “yes/no” basis without revealing classified information. Arms control inspectors might use this technique to verify the presence or absence of monitored items, including both nuclear and non-nuclear materials. Although additional research is needed to study signature aspects such as uniqueness and investigate container-specific scenarios, the technique potentially offers a rapid and cost-effective tool to verify reduction and dismantlement of U.S. and Russian nuclear weapons.« less

Institutional plan FY 1999--FY 2004

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-10-01

Los Alamos has a well-defined and nationally important mission: to reduce the global nuclear danger. This central national security mission consists of four main elements: stockpile stewardship, nuclear materials management, nonproliferation and arms control, and cleanup of the environmental legacy of nuclear weapons activities. The Laboratory provides support for and ensures confidence in the nation`s nuclear stockpile without nuclear testing. This challenge requires the Laboratory to continually hone its scientific acumen and technological capabilities to perform this task reliably using an interdisciplinary approach and advanced experimental and modeling techniques. In the last two National Defense Authorization Acts, Congress identified themore » need to protect the nation from the proliferation of weapons of mass destruction, which includes nuclear, chemical, and biological weapons, and their potential use by terrorists. Los Alamos is applying multidisciplinary science and engineering skills to address these problems. In addition, the Laboratory`s critical programmatic roles in stockpile stewardship and threat reduction are complemented by its waste management operations and environmental restoration work. Information on specific programs is available in Section 2 of this document.« less

Approach to proliferation risk assessment based on multiple objective analysis framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrianov, A.; Kuptsov, I.; Studgorodok 1, Obninsk, Kaluga region, 249030

2013-07-01

The approach to the assessment of proliferation risk using the methods of multi-criteria decision making and multi-objective optimization is presented. The approach allows the taking into account of the specifics features of the national nuclear infrastructure, and possible proliferation strategies (motivations, intentions, and capabilities). 3 examples of applying the approach are shown. First, the approach has been used to evaluate the attractiveness of HEU (high enriched uranium)production scenarios at a clandestine enrichment facility using centrifuge enrichment technology. Secondly, the approach has been applied to assess the attractiveness of scenarios for undeclared production of plutonium or HEU by theft of materialsmore » circulating in nuclear fuel cycle facilities and thermal reactors. Thirdly, the approach has been used to perform a comparative analysis of the structures of developing nuclear power systems based on different types of nuclear fuel cycles, the analysis being based on indicators of proliferation risk.« less

Cytochemistry of the functional domains of the nucleus in normal and in pathologic conditions.

PubMed

Maraldi, N M; Zini, N; Santi, S; Ognibene, A; Rizzoli, R; Mazzotti, G; Manzoli, F A

1998-01-01

By means of ultrastructural cytochemistry significant advances have been made in understanding the functional roles of many nuclear domains. This review gives schematic information about the main nuclear domains involved in replication, transcription, processing and transport of the transcripts in normal and in pathologic conditions. Particular attention is paid to a functional domain that appears to be involved in signal transduction. Data are reported on the intranuclear specific localization of key elements of the polyphosphoinositide signal transduction system in different cell types including human osteosarcoma cell lines. Compared with the compartmentalization of the cytoplasm, the nucleus has long been considered as relatively unstructured. On the other hand, fundamental nuclear functions, such as DNA replication and RNA transcription, can be molecularly characterized also in cell-free systems, suggesting that supramolecular organization is not so strictly required as for other cell functions occurring within intact cytoplasmic organelles. Nevertheless, a stringent organization is required for packing about 200 cm of DNA in the about 30 micron 3 of the nucleus. In the absence of membrane-delimited organelles, the nuclear organization is based on functional compartments, or domains, whose spatial localization involves the nuclear matrix, which shares many properties with the cytoskeleton. The nuclear domains are defined as structural compartments, not necessarily stable but dynamically variable, which perform specific metabolic functions through the partitioning of molecular complexes. Their identification has been made possible in the last few years by the development of specific nuclear probes for confocal and electron microscope immunocytochemistry. Therefore, the complex network of structures and enzymatic functions that make up the nucleus is in several cases yielding to molecular analysis, but a large part remains unknown (Strouboulis and Wolffe, 1996; Laemmli and Tjian, 1996). Rapid advances in understanding the functional role of the nuclear domains have been made recently: in particular, of the nuclear envelope, of the nucleolus, and of RNA splicing. In other cases, e.g. the precise localization of the nuclear domains involved in signal transduction, much remains to be clarified (Forbes and Johnson, 1997). It is conceivable that in the near future unexpected new nuclear domains will come to light and new nuclear functions may emerge, especially in field of post-transcriptional processing and transport of RNAs, and in the relationships between the nucleo-skeleton and enzymic fixed sites involved in replication, transcription and signal transduction. The aim of this review is to provide information about the morphological characteristics, the associated functions and the molecular composition of the main nuclear domains found to date. To simplify the exposition, the main data on each nuclear domain are reported in Tables, together with the principal references on the subject. Figures refer to original findings on some aspects of nuclear domain organization.

Albedo Neutron Dosimetry in a Deep Geological Disposal Repository for High-Level Nuclear Waste.

PubMed

Pang, Bo; Becker, Frank

2017-04-28

Albedo neutron dosemeter is the German official personal neutron dosemeter in mixed radiation fields where neutrons contribute to personal dose. In deep geological repositories for high-level nuclear waste, where neutrons can dominate the radiation field, it is of interest to investigate the performance of albedo neutron dosemeter in such facilities. In this study, the deep geological repository is represented by a shielding cask loaded with spent nuclear fuel placed inside a rock salt emplacement drift. Due to the backscattering of neutrons in the drift, issues concerning calibration of the dosemeter arise. Field-specific calibration of the albedo neutron dosemeter was hence performed with Monte Carlo simulations. In order to assess the applicability of the albedo neutron dosemeter in a deep geological repository over a long time scale, spent nuclear fuel with different ages of 50, 100 and 500 years were investigated. It was found out, that the neutron radiation field in a deep geological repository can be assigned to the application area 'N1' of the albedo neutron dosemeter, which is typical in reactors and accelerators with heavy shielding. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The MPC&A Questionnaire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Danny H; Elwood Jr, Robert H

The questionnaire is the instrument used for recording performance data on the nuclear material protection, control, and accountability (MPC&A) system at a nuclear facility. The performance information provides a basis for evaluating the effectiveness of the MPC&A system. The goal for the questionnaire is to provide an accurate representation of the performance of the MPC&A system as it currently exists in the facility. Performance grades for all basic MPC&A functions should realistically reflect the actual level of performance at the time the survey is conducted. The questionnaire was developed after testing and benchmarking the material control and accountability (MC&A) systemmore » effectiveness tool (MSET) in the United States. The benchmarking exercise at the Idaho National Laboratory (INL) proved extremely valuable for improving the content and quality of the early versions of the questionnaire. Members of the INL benchmark team identified many areas of the questionnaire where questions should be clarified and areas where additional questions should be incorporated. The questionnaire addresses all elements of the MC&A system. Specific parts pertain to the foundation for the facility's overall MPC&A system, and other parts pertain to the specific functions of the operational MPC&A system. The questionnaire includes performance metrics for each of the basic functions or tasks performed in the operational MPC&A system. All of those basic functions or tasks are represented as basic events in the MPC&A fault tree. Performance metrics are to be used during completion of the questionnaire to report what is actually being done in relation to what should be done in the performance of MPC&A functions.« less

78 FR 47015 - Software Requirement Specifications for Digital Computer Software Used in Safety Systems of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-02

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0195] Software Requirement Specifications for Digital Computer Software Used in Safety Systems of Nuclear Power Plants AGENCY: Nuclear Regulatory Commission... issuing a revised regulatory guide (RG), revision 1 of RG 1.172, ``Software Requirement Specifications for...

Natural analogues of nuclear waste glass corrosion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

1999-01-06

This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information availablemore » on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.« less

Plastid-to-Nucleus Retrograde Signals Are Essential for the Expression of Nuclear Starch Biosynthesis Genes during Amyloplast Differentiation in Tobacco BY-2 Cultured Cells1[W][OA

PubMed Central

Enami, Kazuhiko; Ozawa, Tomoki; Motohashi, Noriko; Nakamura, Masayuki; Tanaka, Kan; Hanaoka, Mitsumasa

2011-01-01

Amyloplasts, a subtype of plastid, are found in nonphotosynthetic tissues responsible for starch synthesis and storage. When tobacco (Nicotiana tabacum) Bright Yellow-2 cells are cultured in the presence of cytokinin instead of auxin, their plastids differentiate from proplastids to amyloplasts. In this program, it is well known that the expression of nucleus-encoded starch biosynthesis genes, such as ADP-Glucose Pyrophosphorylase (AgpS) and Granule-Bound Starch Synthase (GBSS), is specifically induced. In this study, we investigated the roles of plastid gene expression in amyloplast differentiation. Microarray analysis of plastid genes revealed that no specific transcripts were induced in amyloplasts. Nevertheless, amyloplast development accompanied with starch biosynthesis was drastically inhibited in the presence of plastid transcription/translation inhibitors. Surprisingly, the expression of nuclear AgpS and GBSS was significantly repressed by the addition of these inhibitors, suggesting that a plastid-derived signal(s) that reflects normal plastid gene expression was essential for nuclear gene expression. A series of experiments was performed to examine the effects of intermediates and inhibitors of tetrapyrrole biosynthesis, since some of the intermediates have been characterized as candidates for plastid-to-nucleus retrograde signals. Addition of levulinic acid, an inhibitor of tetrapyrrole biosynthesis, resulted in the up-regulation of nuclear AgpS and GBSS gene expression as well as starch accumulation, while the addition of heme showed opposite effects. Thus, these results indicate that plastid transcription and/or translation are required for normal amyloplast differentiation, regulating the expression of specific nuclear genes by unknown signaling mechanisms that can be partly mediated by tetrapyrrole intermediates. PMID:21771917

Probabilistic seismic hazard analysis for a nuclear power plant site in southeast Brazil

NASA Astrophysics Data System (ADS)

de Almeida, Andréia Abreu Diniz; Assumpção, Marcelo; Bommer, Julian J.; Drouet, Stéphane; Riccomini, Claudio; Prates, Carlos L. M.

2018-05-01

A site-specific probabilistic seismic hazard analysis (PSHA) has been performed for the only nuclear power plant site in Brazil, located 130 km southwest of Rio de Janeiro at Angra dos Reis. Logic trees were developed for both the seismic source characterisation and ground-motion characterisation models, in both cases seeking to capture the appreciable ranges of epistemic uncertainty with relatively few branches. This logic-tree structure allowed the hazard calculations to be performed efficiently while obtaining results that reflect the inevitable uncertainty in long-term seismic hazard assessment in this tectonically stable region. An innovative feature of the study is an additional seismic source zone added to capture the potential contributions of characteristics earthquake associated with geological faults in the region surrounding the coastal site.

Micro-PIXE studies of Lupinus angustifolius L. after treatment of seeds with molybdenum

NASA Astrophysics Data System (ADS)

Przybylowicz, W. J.; Mesjasz-Przybylowicz, J.; Wouters, K.; Vlassak, K.; Combrink, N. J. J.

1997-02-01

An example of nuclear microprobe application in agriculture is presented. The NAC nuclear microprobe was used to determine quantitative elemental distribution of major, minor and trace elements in Lupinus angustifolius L. (Leguminosae) after treatment of seeds with molybdenum. Experiments were performed in order to establish safe concentration levels and sources of Mo in seed treatments. Elemental distributions in Mo-treated plants and in the non-treated control plants were studied in order to explain how Mo causes toxicity. Some specific regions of Mo and other main and trace elements enrichment were identified.

INITIAL ANALYSIS OF TRANSIENT POWER TIME LAG DUE TO HETEROGENEITY WITHIN THE TREAT FUEL MATRIX.

DOE Office of Scientific and Technical Information (OSTI.GOV)

D.M. Wachs; A.X. Zabriskie, W.R. Marcum

2014-06-01

The topic Nuclear Safety encompasses a broad spectrum of focal areas within the nuclear industry; one specific aspect centers on the performance and integrity of nuclear fuel during a reactivity insertion accident (RIA). This specific accident has proven to be fundamentally difficult to theoretically characterize due to the numerous empirically driven characteristics that quantify the fuel and reactor performance. The Transient Reactor Test (TREAT) facility was designed and operated to better understand fuel behavior under extreme (i.e. accident) conditions; it was shutdown in 1994. Recently, efforts have been underway to commission the TREAT facility to continue testing of advanced accidentmore » tolerant fuels (i.e. recently developed fuel concepts). To aid in the restart effort, new simulation tools are being used to investigate the behavior of nuclear fuels during facility’s transient events. This study focuses specifically on the characterizing modeled effects of fuel particles within the fuel matrix of the TREAT. The objective of this study was to (1) identify the impact of modeled heterogeneity within the fuel matrix during a transient event, and (2) demonstrate acceptable modeling processes for the purpose of TREAT safety analyses, specific to fuel matrix and particle size. Hypothetically, a fuel that is dominantly heterogeneous will demonstrate a clearly different temporal heating response to that of a modeled homogeneous fuel. This time difference is a result of the uniqueness of the thermal diffusivity within the fuel particle and fuel matrix. Using MOOSE/BISON to simulate the temperature time-lag effect of fuel particle diameter during a transient event, a comparison of the average graphite moderator temperature surrounding a spherical particle of fuel was made for both types of fuel simulations. This comparison showed that at a given time and with a specific fuel particle diameter, the fuel particle (heterogeneous) simulation and the homogeneous simulation were related by a multiplier relative to the average moderator temperature. As time increases the multiplier is comparable to the factor found in a previous analytical study from literature. The implementation of this multiplier and the method of analysis may be employed to remove assumptions and increase fidelity for future research on the effect of fuel particles during transient events.« less

Nuclear Energy Gradients for Internally Contracted Complete Active Space Second-Order Perturbation Theory: Multistate Extensions.

PubMed

Vlaisavljevich, Bess; Shiozaki, Toru

2016-08-09

We report the development of the theory and computer program for analytical nuclear energy gradients for (extended) multistate complete active space perturbation theory (CASPT2) with full internal contraction. The vertical shifts are also considered in this work. This is an extension of the fully internally contracted CASPT2 nuclear gradient program recently developed for a state-specific variant by us [MacLeod and Shiozaki, J. Chem. Phys. 2015, 142, 051103]; in this extension, the so-called λ equation is solved to account for the variation of the multistate CASPT2 energies with respect to the change in the amplitudes obtained in the preceding state-specific CASPT2 calculations, and the Z vector equations are modified accordingly. The program is parallelized using the MPI3 remote memory access protocol that allows us to perform efficient one-sided communication. The optimized geometries of the ground and excited states of a copper corrole and benzophenone are presented as numerical examples. The code is publicly available under the GNU General Public License.

Nuclear and analytical methods for investigation of high quality wines

NASA Astrophysics Data System (ADS)

Tonev, D.; Geleva, E.; Grigorov, T.; Goutev, N.; Protohristov, H.; Stoyanov, Ch; Bashev, V.; Tringovska, I.; Kostova, D.

2018-05-01

Nuclear and analytical methods can help to determine the year of production – vintage and the geographical provenance of high quality wines. A complex analytical investigation of Melnik fine wines from “Artarkata” vineyards, Vinogradi village near Melnik in Southwest Bulgaria using different methods and equipment were performed. Nuclear methods, based on measured gamma-ray activity of 137Cs and specific activity of 3H can be used to determine the year of wine production. The specific activity of 137Cs was measured in wines from different vintages using Low-Background High-Resolution Gamma-Spectrometry. Tritium measurements in wine samples were carried out by using a low level liquid scintillation counting in a Packard Tri-Carb 2770 TR/SL liquid scintillation analyzer. The identification of the origin of wines using their chemical fingerprints is of great interest for wine consumers and producers. Determination of 16 chemical elements in samples from soil, wine stems, wine leaves and fine wine from the type Shiroka Melnishka, which are grown in typical Melnik vineyard was made, using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES).

Interferon Regulatory Factor 7 Functions as a Novel Negative Regulator of Pathological Cardiac Hypertrophy

PubMed Central

Jiang, Ding-Sheng; Liu, Yu; Zhou, Heng; Zhang, Yan; Zhang, Xiao-Dong; Zhang, Xiao-Fei; Chen, Ke; Gao, Lu; Peng, Juan; Gong, Hui; Chen, Yingjie; Yang, Qinglin; Liu, Peter P.; Fan, Guo-Chang; Zou, Yunzeng; Li, Hongliang

2017-01-01

Cardiac hypertrophy is a complex pathological process that involves multiple factors including inflammation and apoptosis. Interferon regulatory factor 7 (IRF7) is a multifunctional regulator that participates in immune regulation, cell differentiation, apoptosis, and oncogenesis. However, the role of IRF7 in cardiac hypertrophy remains unclear. We performed aortic banding in cardiac-specific IRF7 transgenic mice, IRF7 knockout mice, and the wild-type littermates of these mice. Our results demonstrated that IRF7 was downregulated in aortic banding–induced animal hearts and cardiomyocytes that had been treated with angiotensin II or phenylephrine for 48 hours. Accordingly, heart-specific overexpression of IRF7 significantly attenuated pressure overload–induced cardiac hypertrophy, fibrosis, and dysfunction, whereas loss of IRF7 led to opposite effects. Moreover, IRF7 protected against angiotensin II–induced cardiomyocyte hypertrophy in vitro. Mechanistically, we identified that IRF7-dependent cardioprotection was mediated through IRF7 binding to inhibitor of κB kinase-β, and subsequent nuclear factor-κB inactivation. In fact, blocking nuclear factor-κB signaling with cardiac-specific inhibitors of κBαS32A/S36A super-repressor transgene counteracted the adverse effect of IRF7 deficiency. Conversely, activation of nuclear factor-κB signaling via a cardiac-specific conditional inhibitor of κB kinase-βS177E/S181E (constitutively active) transgene negated the antihypertrophic effect of IRF7 overexpression. Our data demonstrate that IRF7 acts as a novel negative regulator of pathological cardiac hypertrophy by inhibiting nuclear factor-κB signaling and may constitute a potential therapeutic target for pathological cardiac hypertrophy. PMID:24396025

Designing a new structure for storing nuclear data: Progress of the Working Party for Evaluation Cooperation subgroup #38

DOE PAGES

Mattoon, C. M.; Beck, B. R.

2015-12-24

An international effort is underway to design a new structure for storing and using nuclear reaction data, with the goal of eventually replacing the current standard, ENDF-6. This effort, organized by the Working Party for Evaluation Cooperation, was initiated in 2012 and has resulted in a list of requirements and specifications for how the proposed new structure shall perform. The new structure will take advantage of new developments in computational tools, using a nested hierarchy to store data. Here, the structure can be stored in text form (such as an XML file) for human readability and data sharing, or itmore » can be stored in binary to optimize data access. In this paper, we present the progress towards completing the requirements, specifications and implementation of the new structure.« less

Designing a new structure for storing nuclear data: Progress of the Working Party for Evaluation Cooperation subgroup #38

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattoon, C. M.; Beck, B. R.

An international effort is underway to design a new structure for storing and using nuclear reaction data, with the goal of eventually replacing the current standard, ENDF-6. This effort, organized by the Working Party for Evaluation Cooperation, was initiated in 2012 and has resulted in a list of requirements and specifications for how the proposed new structure shall perform. The new structure will take advantage of new developments in computational tools, using a nested hierarchy to store data. Here, the structure can be stored in text form (such as an XML file) for human readability and data sharing, or itmore » can be stored in binary to optimize data access. In this paper, we present the progress towards completing the requirements, specifications and implementation of the new structure.« less

Impact of Nuclear Laboratory Personnel Credentials & Continuing Education on Nuclear Cardiology Laboratory Quality Operations.

PubMed

Malhotra, Saurabh; Sobieraj, Diana M; Mann, April; Parker, Matthew W

2017-12-22

Background/Objectives: The specific credentials and continuing education (CME/CE) of nuclear cardiology laboratory medical and technical staff are important factors in the delivery of quality imaging services that have not been systematically evaluated. Methods: Nuclear cardiology accreditation application data from the Intersocietal Accreditation Commission (IAC) was used to characterize facilities performing myocardial perfusion imaging by setting, size, previous accreditation and credentials of the medical and technical staff. Credentials and CME/CE were compared against initial accreditation decisions (grant or delay) using multivariable logistic regression. Results: Complete data were available for 1913 nuclear cardiology laboratories from 2011-2014. Laboratories with initial positive accreditation decisions had a greater prevalence of Certification Board in Nuclear Cardiology (CBNC) certified medical directors and specialty credentialed technical directors. Certification and credentials of the medical and technical directors, respectively, staff CME/CE compliance, and assistance of a consultant with the application were positively associated with accreditation decisions. Conclusion: Nuclear cardiology laboratories directed by CBNC-certified physicians and NCT- or PET-credentialed technologists were less likely to receive delay decisions for MPI. CME/CE compliance of both the medical and technical directors was associated with accreditation decision. Medical and technical directors' years of experience were not associated with accreditation decision. Copyright © 2017 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Fundamentals of nuclear medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alazraki, N.P.; Mishkin, F.S.

1988-01-01

The book begins with basic science and statistics relevant to nuclear medicine, and specific organ systems are addressed in separate chapters. A section of the text also covers imaging of groups of disease processes (eg, trauma, cancer). The authors present a comparison between nuclear medicine techniques and other diagnostic imaging studies. A table is given which comments on sensitivities and specificities of common nuclear medicine studies. The sensitivities and specificities are categorized as very high, high, moderate, and so forth.

Preclinical evaluation of nuclear morphometry and tissue topology for breast carcinoma detection and margin assessment

PubMed Central

Nyirenda, Ndeke; Farkas, Daniel L.

2010-01-01

Prevention and early detection of breast cancer are the major prophylactic measures taken to reduce the breast cancer related mortality and morbidity. Clinical management of breast cancer largely relies on the efficacy of the breast-conserving surgeries and the subsequent radiation therapy. A key problem that limits the success of these surgeries is the lack of accurate, real-time knowledge about the positive tumor margins in the surgically excised tumors in the operating room. This leads to tumor recurrence and, hence, the need for repeated surgeries. Current intraoperative techniques such as frozen section pathology or touch imprint cytology severely suffer from poor sampling and non-optimal detection sensitivity. Even though histopathology analysis can provide information on positive tumor margins post-operatively (~2–3 days), this information is of no immediate utility in the operating rooms. In this article, we propose a novel image analysis method for tumor margin assessment based on nuclear morphometry and tissue topology and demonstrate its high sensitivity/specificity in preclinical animal model of breast carcinoma. The method relies on imaging nuclear-specific fluorescence in the excised surgical specimen and on extracting nuclear morphometric parameters (size, number, and area fraction) from the spatial distribution of the observed fluorescence in the tissue. We also report the utility of tissue topology in tumor margin assessment by measuring the fractal dimension in the same set of images. By a systematic analysis of multiple breast tissues specimens, we show here that the proposed method is not only accurate (~97% sensitivity and 96% specificity) in thin sections, but also in three-dimensional (3D) thick tissues that mimic the realistic lumpectomy specimens. Our data clearly precludes the utility of nuclear size as a reliable diagnostic criterion for tumor margin assessment. On the other hand, nuclear area fraction addresses this issue very effectively since it is a combination of both nuclear size and count in any given region of the analyzed image, and thus yields high sensitivity and specificity (~97%) in tumor detection. This is further substantiated by an independent parameter, fractal dimension, based on the tissue topology. Although the basic definition of cancer as an uncontrolled cell growth entails a high nuclear density in tumor regions, a simple but systematic exploration of nuclear distribution in thick tissues by nuclear morphometry and tissue topology as performed in this study has never been carried out, to the best of our knowledge. We discuss the practical aspects of implementing this imaging approach in automated tissue sampling scenario where the accuracy of tumor margin assessment can be significantly increased by scanning the entire surgical specimen rather than sampling only a few sections as in current histopathology analysis. PMID:20446030

Development, Application, and Implementation of RAMCAP to Characterize Nuclear Power Plant Risk From Terrorism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaertner, John P.; Teagarden, Grant A.

2006-07-01

In response to increased interest in risk-informed decision making regarding terrorism, EPRI and ERIN Engineering were selected by U.S. DHS and ASME to develop and demonstrate the RAMCAP method for nuclear power plant (NPP) risk assessment. The objective is to characterize plant-specific NPP risk for risk management opportunities and to provide consistent information for DHS decision making. This paper is an update of this project presented at the American Nuclear Society (ANS) International Topical Meeting on Probabilistic Safety Analysis (PSA05) in September, 2005. The method uses a characterization of risk as a function of Consequence, Vulnerability, and Threat. For eachmore » site, worst case scenarios are developed for each of sixteen benchmark threats. Nuclear RAMCAP hypothesizes that the intent of the perpetrator is to cause offsite radiological consequences. Specific targets are the reactor core, the spent fuel pool, and nuclear spent fuel in a dry storage facility (ISFSI). Results for each scenario are presented as conditional risk for financial loss, early fatalities and early injuries. Expected consequences for each scenario are quantified, while vulnerability is estimated on a relative likelihood scale. Insights for other societal risks are provided. Although threat frequencies are not provided, target attractiveness and threat deterrence are estimated. To assure efficiency, completeness, and consistency; results are documented using standard RAMCAP Evaluator software. Trial applications were successfully performed at four plant sites. Implementation at all other U.S. commercial sites is underway, supported by the Nuclear Sector Coordinating Council (NSCC). Insights from RAMCAP results at 23 U.S. plants completed to date have been compiled and presented to the NSCC. Results are site-specific. Physical security barriers, an armed security force, preparedness for design-basis threats, rugged design against natural hazards, multiple barriers between fuel and environment, accident mitigation capability, severe accident management procedures, and offsite emergency plans are risk-beneficial against all threat types. (authors)« less

The nuclear lamina and heterochromatin: a complex relationship.

PubMed

Bank, Erin M; Gruenbaum, Yosef

2011-12-01

In metazoan cells, the heterochromatin is generally localized at the nuclear periphery, whereas active genes are preferentially found in the nuclear interior. In the present paper, we review current evidence showing that components of the nuclear lamina interact directly with heterochromatin, which implicates the nuclear lamina in a mechanism of specific gene retention at the nuclear periphery and release to the nuclear interior upon gene activation. We also discuss recent data showing that mutations in lamin proteins affect gene positioning and expression, providing a potential mechanism for how these mutations lead to tissue-specific diseases.

10 CFR 50.36a - Technical specifications on effluents from nuclear power reactors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... reactors. 50.36a Section 50.36a Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND...; Ineligibility of Certain Applicants § 50.36a Technical specifications on effluents from nuclear power reactors..., including expected occurrences, as low as is reasonably achievable, each licensee of a nuclear power reactor...

10 CFR 50.36a - Technical specifications on effluents from nuclear power reactors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... reactors. 50.36a Section 50.36a Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND...; Ineligibility of Certain Applicants § 50.36a Technical specifications on effluents from nuclear power reactors..., including expected occurrences, as low as is reasonably achievable, each licensee of a nuclear power reactor...

10 CFR 50.36a - Technical specifications on effluents from nuclear power reactors.

Code of Federal Regulations, 2014 CFR

2014-01-01

... reactors. 50.36a Section 50.36a Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND...; Ineligibility of Certain Applicants § 50.36a Technical specifications on effluents from nuclear power reactors..., including expected occurrences, as low as is reasonably achievable, each licensee of a nuclear power reactor...

Fingerprinting analysis of Saposhnikovia divaricata using 1H nuclear magnetic resonance spectroscopy and high performance liquid chromatography.

PubMed

Xin, Yue-Yang; Deng, An-Jun; Du, Guan-Hua; Zhang, Jin-Lan; Qin, Hai-Lin

2010-09-01

The (1)H nuclear magnetic resonance ((1)H NMR) fingerprints of fractionated non-polar and polar extracts (control substance for plant drug [CSPD] A and B) from the roots of 12 specimens of Saposhnikovia divaricata (Turcz.) Schischk were achieved with Fourier Transform (FT)-NMR spectrometer and assigned by comparison to each other and to the (1)H NMR spectra of the isolated individual compounds. These fingerprints were found to be uniform in terms of the specificity for the implication of all 12 specimens being systematically of the same origin. The uniformity was further affirmed by high performance liquid chromatography (HPLC), which also revealed exactly identical specificity for the identified S. divaricata species with the (1)H NMR appearances of corresponding CSPD on the part of the composition of characteristic constituents when comparing to corresponding individual compounds. This investigation unambiguously shows that the specific signals from the chemotaxonomically significant compounds of chromones and coumarins in S. divaricata are exhibited distinctively in the composite features of both (1)H NMR fingerprints and HPLC profiles. The (1)H NMR and HPLC profiles established can successfully be used as reference for the authentication of the origin of S. divaricata species as well as for chemotaxonomic studies.

Case study of medical evacuation before and after the Fukushima Daiichi nuclear power plant accident in the great east Japan earthquake.

PubMed

Okumura, Tetsu; Tokuno, Shinichi

2015-01-01

In Japan, participants in the disaster-specific medical transportation system have received ongoing training since 2002, incorporating lessons learned from the Great Hanshin Earthquake. The Great East Japan Earthquake occurred on March 11, 2011, and the very first disaster-specific medical transport was performed. This article reviews in detail the central government's control and coordination of the disaster medical transportation process following the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Plant Accident. In total, 124 patients were air transported under the coordination of the C5 team in the emergency response headquarter of the Japanese Government. C5 includes experts from the Cabinet Office, Cabinet Secretariat, Fire Defense Agency, Ministry of Health, Labour and Welfare, and Ministry of Defense. In the 20-30 km evacuation zone around the Fukushima Daiichi nuclear power plant, 509 bedridden patients were successfully evacuated without any fatalities during transportation. Many lessons have been learned in disaster-specific medical transportation. The national government, local government, police, and fire agencies have made significant progress in their mutual communication and collaboration. Fortunately, hospital evacuation from the 20-30 km area was successfully performed with the aid of local emergency physicians and Disaster Medical Assistance Teams (DMATs) who have vast experience in patient transport in the course of day-to-day activities. The emergency procedures that are required during crises are an extension of basic daily procedures that are performed by emergency medical staff and first responders, such as fire fighters, emergency medical technicians, or police officers. Medical facilities including nursing homes should have a plan for long-distance (over 100 km) evacuation, and the plan should be routinely reevaluated with full-scale exercises. In addition, hospital evacuation in disaster settings should be supervised by emergency physicians and be handled by disaster specialists who are accustomed to patient transportation on a daily basis.

Advanced Laser-Compton Gamma-Ray Sources for Nuclear Materials Detection, Assay and Imaging

NASA Astrophysics Data System (ADS)

Barty, C. P. J.

2015-10-01

Highly-collimated, polarized, mono-energetic beams of tunable gamma-rays may be created via the optimized Compton scattering of pulsed lasers off of ultra-bright, relativistic electron beams. Above 2 MeV, the peak brilliance of such sources can exceed that of the world's largest synchrotrons by more than 15 orders of magnitude and can enable for the first time the efficient pursuit of nuclear science and applications with photon beams, i.e. Nuclear Photonics. Potential applications are numerous and include isotope-specific nuclear materials management, element-specific medical radiography and radiology, non-destructive, isotope-specific, material assay and imaging, precision spectroscopy of nuclear resonances and photon-induced fission. This review covers activities at the Lawrence Livermore National Laboratory related to the design and optimization of mono-energetic, laser-Compton gamma-ray systems and introduces isotope-specific nuclear materials detection and assay applications enabled by them.

Assessing the need for an update of a probabilistic seismic hazard analysis using a SSHAC Level 1 study and the Seismic Hazard Periodic Reevaluation Methodology

DOE PAGES

Payne, Suzette J.; Coppersmith, Kevin J.; Coppersmith, Ryan; ...

2017-08-23

A key decision for nuclear facilities is evaluating the need for an update of an existing seismic hazard analysis in light of new data and information that has become available since the time that the analysis was completed. We introduce the newly developed risk-informed Seismic Hazard Periodic Review Methodology (referred to as the SHPRM) and present how a Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 probabilistic seismic hazard analysis (PSHA) was performed in an implementation of this new methodology. The SHPRM offers a defensible and documented approach that considers both the changes in seismic hazard and engineering-based risk informationmore » of an existing nuclear facility to assess the need for an update of an existing PSHA. The SHPRM has seven evaluation criteria that are employed at specific analysis, decision, and comparison points which are applied to seismic design categories established for nuclear facilities in United States. The SHPRM is implemented using a SSHAC Level 1 study performed for the Idaho National Laboratory, USA. The implementation focuses on the first six of the seven evaluation criteria of the SHPRM which are all provided from the SSHAC Level 1 PSHA. Finally, to illustrate outcomes of the SHPRM that do not lead to the need for an update and those that do, the example implementations of the SHPRM are performed for nuclear facilities that have target performance goals expressed as the mean annual frequency of unacceptable performance at 1x10 -4, 4x10 -5 and 1x10 -5.« less

Assessing the need for an update of a probabilistic seismic hazard analysis using a SSHAC Level 1 study and the Seismic Hazard Periodic Reevaluation Methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, Suzette J.; Coppersmith, Kevin J.; Coppersmith, Ryan

A key decision for nuclear facilities is evaluating the need for an update of an existing seismic hazard analysis in light of new data and information that has become available since the time that the analysis was completed. We introduce the newly developed risk-informed Seismic Hazard Periodic Review Methodology (referred to as the SHPRM) and present how a Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 probabilistic seismic hazard analysis (PSHA) was performed in an implementation of this new methodology. The SHPRM offers a defensible and documented approach that considers both the changes in seismic hazard and engineering-based risk informationmore » of an existing nuclear facility to assess the need for an update of an existing PSHA. The SHPRM has seven evaluation criteria that are employed at specific analysis, decision, and comparison points which are applied to seismic design categories established for nuclear facilities in United States. The SHPRM is implemented using a SSHAC Level 1 study performed for the Idaho National Laboratory, USA. The implementation focuses on the first six of the seven evaluation criteria of the SHPRM which are all provided from the SSHAC Level 1 PSHA. Finally, to illustrate outcomes of the SHPRM that do not lead to the need for an update and those that do, the example implementations of the SHPRM are performed for nuclear facilities that have target performance goals expressed as the mean annual frequency of unacceptable performance at 1x10 -4, 4x10 -5 and 1x10 -5.« less

Embedded Sensors and Controls to Improve Component Performance and Reliability -- Loop-scale Testbed Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melin, Alexander M.; Kisner, Roger A.

2016-09-01

Embedded instrumentation and control systems that can operate in extreme environments are challenging to design and operate. Extreme environments limit the options for sensors and actuators and degrade their performance. Because sensors and actuators are necessary for feedback control, these limitations mean that designing embedded instrumentation and control systems for the challenging environments of nuclear reactors requires advanced technical solutions that are not available commercially. This report details the development of testbed that will be used for cross-cutting embedded instrumentation and control research for nuclear power applications. This research is funded by the Department of Energy's Nuclear Energy Enabling Technologymore » program's Advanced Sensors and Instrumentation topic. The design goal of the loop-scale testbed is to build a low temperature pump that utilizes magnetic bearing that will be incorporated into a water loop to test control system performance and self-sensing techniques. Specifically, this testbed will be used to analyze control system performance in response to nonlinear and cross-coupling fluid effects between the shaft axes of motion, rotordynamics and gyroscopic effects, and impeller disturbances. This testbed will also be used to characterize the performance losses when using self-sensing position measurement techniques. Active magnetic bearings are a technology that can reduce failures and maintenance costs in nuclear power plants. They are particularly relevant to liquid salt reactors that operate at high temperatures (700 C). Pumps used in the extreme environment of liquid salt reactors provide many engineering challenges that can be overcome with magnetic bearings and their associated embedded instrumentation and control. This report will give details of the mechanical design and electromagnetic design of the loop-scale embedded instrumentation and control testbed.« less

Protein Sub-Nuclear Localization Prediction Using SVM and Pfam Domain Information

PubMed Central

Kumar, Ravindra; Jain, Sohni; Kumari, Bandana; Kumar, Manish

2014-01-01

The nucleus is the largest and the highly organized organelle of eukaryotic cells. Within nucleus exist a number of pseudo-compartments, which are not separated by any membrane, yet each of them contains only a specific set of proteins. Understanding protein sub-nuclear localization can hence be an important step towards understanding biological functions of the nucleus. Here we have described a method, SubNucPred developed by us for predicting the sub-nuclear localization of proteins. This method predicts protein localization for 10 different sub-nuclear locations sequentially by combining presence or absence of unique Pfam domain and amino acid composition based SVM model. The prediction accuracy during leave-one-out cross-validation for centromeric proteins was 85.05%, for chromosomal proteins 76.85%, for nuclear speckle proteins 81.27%, for nucleolar proteins 81.79%, for nuclear envelope proteins 79.37%, for nuclear matrix proteins 77.78%, for nucleoplasm proteins 76.98%, for nuclear pore complex proteins 88.89%, for PML body proteins 75.40% and for telomeric proteins it was 83.33%. Comparison with other reported methods showed that SubNucPred performs better than existing methods. A web-server for predicting protein sub-nuclear localization named SubNucPred has been established at http://14.139.227.92/mkumar/subnucpred/. Standalone version of SubNucPred can also be downloaded from the web-server. PMID:24897370

Benefits of Nuclear Electric Propulsion for Outer Planet Exploration

NASA Technical Reports Server (NTRS)

Kos, Larry; Johnson, Les; Jones, Jonathan; Trausch, Ann; Eberle, Bill; Woodcock, Gordon; Brady, Hugh J. (Technical Monitor)

2002-01-01

Nuclear electric propulsion (NEP) offers significant benefits to missions for outer planet exploration. Reaching outer planet destinations, especially beyond Jupiter, is a struggle against time and distance. For relatively near missions, such as a Europa lander, conventional chemical propulsion and NEP offer similar performance and capabilities. For challenging missions such as a Pluto orbiter, neither chemical nor solar electric propulsion are capable while NEP offers acceptable performance. Three missions are compared in this paper: Europa lander, Pluto orbiter, and Titan sample return, illustrating how performance of conventional and advanced propulsion systems vary with increasing difficulty. The paper presents parametric trajectory performance data for NEP. Preliminary mass/performance estimates are provided for a Europa lander and a Titan sample return system, to derive net payloads for NEP. The NEP system delivers payloads and ascent/descent spacecraft to orbit around the target body, and for sample return, delivers the sample carrier system from Titan orbit to an Earth transfer trajectory. A representative scientific payload 500 kg was assumed, typical for a robotic mission. The resulting NEP systems are 100-kWe class, with specific impulse from 6000 to 9000 seconds.

Diagnostic utility of hepatocyte nuclear factor 1-beta immunoreactivity in endometrial carcinomas: lack of specificity for endometrial clear cell carcinoma.

PubMed

Fadare, Oluwole; Liang, Sharon X

2012-12-01

Hepatocyte nuclear factor 1-beta (HNF1β) has recently emerged as a relatively sensitive and specific marker for ovarian clear cell carcinoma. The purpose of this study is to assess the diagnostic utility of this marker for endometrial clear cell carcinoma. Immunohistochemical analysis was performed on 75 endometrial tissues using a goat polyclonal antibody raised against a peptide mapping at the C-terminus of human HNF1β protein. The 75 cases included 15 clear cell carcinomas, 20 endometrioid carcinomas, 15 endometrial serous carcinomas/uterine papillary serous carcinomas, 20 cases of normal endometrium, 2 cases of clear cell metaplasia, and 3 cases of Arias Stella reaction. Staining interpretations were based on a semiquantitative scoring system, a 0 to 12+ continuous numerical scale that was derived by multiplying the extent of staining (0 to 4+ scale) by the intensity of staining (0 to 3+ scale) for each case. HNF1β expression was found to be present in a wide spectrum of tissues. Twenty-seven (54%) of the 50 carcinomas displayed at least focal nuclear HNF1β expression, including 11 (73%) of 15, 9 (60%) of 15, and 7 (35%) of 20 clear cell, serous, and endometrioid carcinomas, respectively. The average nuclear staining scores for clear cell carcinomas, endometrioid carcinomas, and serous carcinomas were 5.2, 1.4, and 4.1, respectively. Clear cell carcinomas and endometrioid carcinomas displayed statistically significant differences regarding their nuclear staining scores (P = 0.0027), but clear cell carcinomas and endometrial serous carcinomas did not (P = 0.45). The calculated sensitivity of any nuclear HNF1β expression in classifying a carcinoma as being of the clear cell histotype was 73%, whereas the specificity was 54%. Nineteen of 20 normal endometrium samples displayed at least focal nuclear expression of HNF1β, and this expression was often diffuse. The 5 cases of benign histologic mimics of clear cell carcinomas (Arias Stella reaction and clear cell metaplasia) displayed some degree of HNF1β immunoreactivity, with an average nuclear staining score of 7.3. We conclude that although HNF1β is frequently expressed in clear cell carcinomas, it should be used with caution as a diagnostic marker because of its lack of specificity. It neither distinguishes endometrial serous carcinomas from clear cell carcinomas nor clear cell carcinomas from its benign mimics. The greatest diagnostic utility of HNF1β expression may be in a supportive evidentiary role favoring clear cell carcinoma when the principal differential diagnostic consideration is endometrioid carcinoma.

On-line condition monitoring applications in nuclear power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hastiemian, H. M.; Feltus, M. A.

2006-07-01

Existing signals from process instruments in nuclear power plants can be sampled while the plant is operating and analyzed to verify the static and dynamic performance of process sensors, identify process-to-sensor problems, detect instrument anomalies such as venturi fouling, measure the vibration of the reactor vessel and its internals, or detect thermal hydraulic anomalies within the reactor coolant system. These applications are important in nuclear plants to satisfy a variety of objectives such as: 1) meeting the plant technical specification requirements; 2) complying with regulatory regulations; 3) guarding against equipment and process degradation; 4) providing a means for incipient failuremore » detection and predictive maintenance; or 5) identifying the root cause of anomalies in equipment and plant processes. The technologies that are used to achieve these objectives are collectively referred to as 'on-line condition monitoring.' This paper presents a review of key elements of these technologies, provides examples of their use in nuclear power plants, and illustrates how they can be integrated into an on-line condition monitoring system for nuclear power plants. (authors)« less

Study of nuclear medicine practices in Portugal from an internal dosimetry perspective.

PubMed

Bento, J; Teles, P; Neves, M; Santos, A I; Cardoso, G; Barreto, A; Alves, F; Guerreiro, C; Rodrigues, A; Santos, J A M; Capelo, C; Parafita, R; Martins, B

2012-05-01

Nuclear medicine practices involve the handling of a wide range of pharmaceuticals labelled with different radionuclides, for diagnostic and therapeutic purposes. This work intends to evaluate the potential risks of internal contamination of nuclear medicine staff in several Portuguese nuclear medicine services and to conclude about the requirement of a routine internal monitoring. A methodology proposed by the International Atomic Energy Agency (IAEA), providing a set of criteria to determine the need, or not, for an internal monitoring programme, was applied. The evaluation of the risk of internal contaminations in a given set of working conditions is based on the type and amount of radionuclides being handled, as well as the safety conditions with which they are manipulated. The application of the IAEA criteria showed that 73.1% of all the workers included in this study should be integrated in a routine monitoring programme for internal contaminations; more specifically, 100% of workers performing radioimmunoassay techniques should be monitored. This study suggests that a routine monitoring programme for internal exposures should be implemented in Portugal for most nuclear medicine workers.

Nuclear starburst activity induced by elongated bulges in spiral galaxies

NASA Astrophysics Data System (ADS)

Kim, Eunbin; Kim, Sungsoo S.; Choi, Yun-Young; Lee, Gwang-Ho; de Grijs, Richard; Lee, Myung Gyoon; Hwang, Ho Seong

2018-06-01

We study the effects of bulge elongation on the star formation activity in the centres of spiral galaxies using the data from the Sloan Digital Sky Survey Data Release 7. We construct a volume-limited sample of face-on spiral galaxies with Mr < -19.5 mag at 0.02 ≤z< 0.055 by excluding barred galaxies, where the aperture of the SDSS spectroscopic fibre covers the bulges of the galaxies. We adopt the ellipticity of bulges measured by Simard et al. (2011) who performed two-dimensional bulge+disc decompositions using the SDSS images of galaxies, and identify nuclear starbursts using the fibre specific star formation rates derived from the SDSS spectra. We find a statistically significant correlation between bulge elongation and nuclear starbursts in the sense that the fraction of nuclear starbursts increases with bulge elongation. This correlation is more prominent for fainter and redder galaxies, which exhibit higher ratios of elongated bulges. We find no significant environmental dependence of the correlation between bulge elongation and nuclear starbursts. These results suggest that non-axisymmetric bulges can efficiently feed the gas into the centre of galaxies to trigger nuclear starburst activity.

Qualification of heavy water based irradiation device in the JSI TRIGA reactor for irradiations of FT-TIMS samples for nuclear safeguards

NASA Astrophysics Data System (ADS)

Radulović, Vladimir; Kolšek, Aljaž; Fauré, Anne-Laure; Pottin, Anne-Claire; Pointurier, Fabien; Snoj, Luka

2018-03-01

The Fission Track Thermal Ionization Mass Spectrometry (FT-TIMS) method is considered as the reference method for particle analysis in the field of nuclear Safeguards for measurements of isotopic compositions (fissile material enrichment levels) in micrometer-sized uranium particles collected in nuclear facilities. An integral phase in the method is the irradiation of samples in a very well thermalized neutron spectrum. A bilateral collaboration project was carried out between the Jožef Stefan Institute (JSI, Slovenia) and the Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA, France) to determine whether the JSI TRIGA reactor could be used for irradiations of samples for the FT-TIMS method. This paper describes Monte Carlo simulations, experimental activation measurements and test irradiations performed in the JSI TRIGA reactor, firstly to determine the feasibility, and secondly to design and qualify a purpose-built heavy water based irradiation device for FT-TIMS samples. The final device design has been shown experimentally to meet all the required performance specifications.

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase in nuclei and rimmed vacuoles of muscle fibers in DMRV (distal myopathy with rimmed vacuoles).

PubMed

Ishihara, Shoichiro; Tomimitsu, Hiroyuki; Fujigasaki, Hiroto; Saito, Fumiaki; Mizusawa, Hidehiro

2008-03-01

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) is a key molecule in the pathogenesis of distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (HIBM) and almost all such patients have some mutations in GNE. However, subcellular localization of GNE and the mechanism of muscular damage have not been clarified. A rabbit polyclonal antibody for GNE was prepared. Immunohistochemistry was performed using anti-GNE and anti-nuclear protein antibodies. Western blotting with subcellular fractionated proteins was performed to determine subcellular localization of GNE. The sizes of myonuclei were quantified in muscle biopsies from patients with DMRV and amyotrophic lateral sclerosis (ALS). In DMRV muscles, immunohistochemistry identified GNE in sarcoplasm and specifically in myonuclei and rimmed vacuoles (RV). Nuclear proteins were also found in RVs. Immunohistochemistry showed colocalization of GNE and emerin in C2C12 cells. Western blotting revealed the presence of GNE in nuclear fractions of human embryonic kidney (HEK) 293T cells. The mean size of myonuclei of DMRV was significantly larger than that of ALS. GNE is present in myonuclei near nuclear membrane. Our results suggest that myonuclei are involved in RV formation in DMRV, and that mutant GNE in myonuclei seems to play some role in this process.

A Nuclear Cryogenic Propulsion Stage for Near-Term Space Missions

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Adams, Robert B.; Bechtel, Ryan D.; Borowski, Stanley K.; George, Jeffrey A.

2013-01-01

The potential capability of NTP is game changing for space exploration. A first generation NCPS could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Near-term NCPS systems would provide a foundation for the development of significantly more advanced, higher performance systems. John F. Kennedy made his historic special address to Congress on the importance of space on May 25, 1961, "First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth..." This was accomplished. John F. Kennedy also made a second request, "Secondly... accelerate development of the Rover nuclear rocket. This gives promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the Moon, perhaps to the very end of the solar system itself." The investment in the Rover nuclear rocket program provided the foundation of technology that gives us assurance for greater performing rockets that are capable of taking us further into space. Combined with current technologies, the vision to go beyond the Moon and to the very end of the solar system can be realized with space nuclear propulsion and power.

Mechanisms for training security inspectors to enhance human performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkhalter, H.E.; Sessions, J.C.

The Department of Energy (DOE) has established qualification standards for protective force personnel employed at nuclear facilities (10 CFR Part 1046 (Federal Register)). Training mechanisms used at Los Alamos to enhance human performance in meeting DOE standards include, but are not limited to, the following: for cardio-respiratory training, they utilize distance running, interval training, sprint training, pacing, indoor aerobics and circuit training; for muscular strength, free weights, weight machines, light hand weights, grip strength conditioners, and calistenics are employed; for muscular endurance, participants do high repetitions (15 - 40) using dumbbells, flex weights, resistive rubber bands, benches, and calisthenics; formore » flexibility, each training session devotes specific times to stretch the muscles involved for a particular activity. These training mechanisms with specific protocols can enhance human performance.« less

Comparison of taxon-specific versus general locus sets for targeted sequence capture in plant phylogenomics.

PubMed

Chau, John H; Rahfeldt, Wolfgang A; Olmstead, Richard G

2018-03-01

Targeted sequence capture can be used to efficiently gather sequence data for large numbers of loci, such as single-copy nuclear loci. Most published studies in plants have used taxon-specific locus sets developed individually for a clade using multiple genomic and transcriptomic resources. General locus sets can also be developed from loci that have been identified as single-copy and have orthologs in large clades of plants. We identify and compare a taxon-specific locus set and three general locus sets (conserved ortholog set [COSII], shared single-copy nuclear [APVO SSC] genes, and pentatricopeptide repeat [PPR] genes) for targeted sequence capture in Buddleja (Scrophulariaceae) and outgroups. We evaluate their performance in terms of assembly success, sequence variability, and resolution and support of inferred phylogenetic trees. The taxon-specific locus set had the most target loci. Assembly success was high for all locus sets in Buddleja samples. For outgroups, general locus sets had greater assembly success. Taxon-specific and PPR loci had the highest average variability. The taxon-specific data set produced the best-supported tree, but all data sets showed improved resolution over previous non-sequence capture data sets. General locus sets can be a useful source of sequence capture targets, especially if multiple genomic resources are not available for a taxon.

Structure of Importin-α from a Filamentous Fungus in Complex with a Classical Nuclear Localization Signal.

PubMed

Bernardes, Natalia E; Takeda, Agnes A S; Dreyer, Thiago R; Freitas, Fernanda Z; Bertolini, Maria Célia; Fontes, Marcos R M

2015-01-01

Neurospora crassa is a filamentous fungus that has been extensively studied as a model organism for eukaryotic biology, providing fundamental insights into cellular processes such as cell signaling, growth and differentiation. To advance in the study of this multicellular organism, an understanding of the specific mechanisms for protein transport into the cell nucleus is essential. Importin-α (Imp-α) is the receptor for cargo proteins that contain specific nuclear localization signals (NLSs) that play a key role in the classical nuclear import pathway. Structures of Imp-α from different organisms (yeast, rice, mouse, and human) have been determined, revealing that this receptor possesses a conserved structural scaffold. However, recent studies have demonstrated that the Impα mechanism of action may vary significantly for different organisms or for different isoforms from the same organism. Therefore, structural, functional, and biophysical characterization of different Impα proteins is necessary to understand the selectivity of nuclear transport. Here, we determined the first crystal structure of an Impα from a filamentous fungus which is also the highest resolution Impα structure already solved to date (1.75 Å). In addition, we performed calorimetric analysis to determine the affinity and thermodynamic parameters of the interaction between Imp-α and the classical SV40 NLS peptide. The comparison of these data with previous studies on Impα proteins led us to demonstrate that N. crassa Imp-α possess specific features that are distinct from mammalian Imp-α but exhibit important similarities to rice Imp-α, particularly at the minor NLS binding site.

Preliminary neutronics design of china lead-alloy cooled demonstration reactor (CLEAR-III) for nuclear waste transmutation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Z.; Southwest Science and Technology Univ., No.350 Shushanhu Road, Shushan District, Hefei, Anhui, 230031; Chen, Y.

2012-07-01

China Lead-Alloy cooled Demonstration Reactor (CLEAR-III), which is the concept of lead-bismuth cooled accelerator driven sub-critical reactor for nuclear waste transmutation, was proposed and designed by FDS team in China. In this study, preliminary neutronics design studies have primarily focused on three important performance parameters including Transmutation Support Ratio (TSR), effective multiplication factor and blanket thermal power. The constraint parameters, such as power peaking factor and initial TRU loading, were also considered. In the specific design, uranium-free metallic dispersion fuel of (TRU-Zr)-Zr was used as one of the CLEAR-III fuel types and the ratio between MA and Pu was adjustedmore » to maximize transmutation ratio. In addition, three different fuel zones differing in the TRU fraction of the fuel were respectively employed for this subcritical reactor, and the zone sizes and TRU fractions were determined such that the linear powers of these zones were close to each other. The neutronics calculations and analyses were performed by using Multi-Functional 4D Neutronics Simulation System named VisualBUS and nuclear data library HENDL (Hybrid Evaluated Nuclear Data Library). In the preliminary design, the maximum TSRLLMA was {approx}11 and the blanket thermal power was {approx}1000 MW when the effective multiplication factor was 0.98. The results showed that good performance of transmutation could be achieved based on the subcritical reactor loaded with uranium-free fuel. (authors)« less

Technical Readiness and Gaps Analysis of Commercial Optical Materials and Measurement Systems for Advanced Small Modular Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anheier, Norman C.; Suter, Jonathan D.; Qiao, Hong

2013-08-06

This report intends to support Department of Energy’s Office of Nuclear Energy (DOE-NE) Nuclear Energy Research and Development Roadmap and industry stakeholders by evaluating optical-based instrumentation and control (I&C) concepts for advanced small modular reactor (AdvSMR) applications. These advanced designs will require innovative thinking in terms of engineering approaches, materials integration, and I&C concepts to realize their eventual viability and deployability. The primary goals of this report include: 1. Establish preliminary I&C needs, performance requirements, and possible gaps for AdvSMR designs based on best available published design data. 2. Document commercial off-the-shelf (COTS) optical sensors, components, and materials in termsmore » of their technical readiness to support essential AdvSMR in-vessel I&C systems. 3. Identify technology gaps by comparing the in-vessel monitoring requirements and environmental constraints to COTS optical sensor and materials performance specifications. 4. Outline a future research, development, and demonstration (RD&D) program plan that addresses these gaps and develops optical-based I&C systems that enhance the viability of future AdvSMR designs. The development of clean, affordable, safe, and proliferation-resistant nuclear power is a key goal that is documented in the Nuclear Energy Research and Development Roadmap. This roadmap outlines RD&D activities intended to overcome technical, economic, and other barriers, which currently limit advances in nuclear energy. These activities will ensure that nuclear energy remains a viable component to this nation’s energy security.« less

Status of Fuel Development and Manufacturing for Space Nuclear Reactors at BWX Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmack, W.J.; Husser, D.L.; Mohr, T.C.

2004-02-04

New advanced nuclear space propulsion systems will soon seek a high temperature, stable fuel form. BWX Technologies Inc (BWXT) has a long history of fuel manufacturing. UO2, UCO, and UCx have been fabricated at BWXT for various US and international programs. Recent efforts at BWXT have focused on establishing the manufacturing techniques and analysis capabilities needed to provide a high quality, high power, compact nuclear reactor for use in space nuclear powered missions. To support the production of a space nuclear reactor, uranium nitride has recently been manufactured by BWXT. In addition, analytical chemistry and analysis techniques have been developedmore » to provide verification and qualification of the uranium nitride production process. The fabrication of a space nuclear reactor will require the ability to place an unclad fuel form into a clad structure for assembly into a reactor core configuration. To this end, BWX Technologies has reestablished its capability for machining, GTA welding, and EB welding of refractory metals. Specifically, BWX Technologies has demonstrated GTA welding of niobium flat plate and EB welding of niobium and Nb-1Zr tubing. In performing these demonstration activities, BWX Technologies has established the necessary infrastructure to manufacture UO2, UCx, or UNx fuel, components, and complete reactor assemblies in support of space nuclear programs.« less

MCNPX CALCULATIONS OF SPECIFIC ABSORBED FRACTIONS IN SOME ORGANS OF THE HUMAN BODY DUE TO APPLICATION OF 133Xe, 99mTc and 81mKr RADIONUCLIDES.

PubMed

Jovanovic, Z; Krstic, D; Nikezic, D; Ros, J M Gomez; Ferrari, P

2018-03-01

Monte Carlo simulations were performed to evaluate treatment doses with wide spread used radionuclides 133Xe, 99mTc and 81mKr. These different radionuclides are used in perfusion or ventilation examinations in nuclear medicine and as indicators for cardiovascular and pulmonary diseases. The objective of this work was to estimate the specific absorbed fractions in surrounding organs and tissues, when these radionuclides are incorporated in the lungs. For this purpose a voxel thorax model has been developed and compared with the ORNL phantom. All calculations and simulations were performed by means of the MCNP5/X code.

Radioisotope Electric Propulsion (REP): A Near-Term Approach to Nuclear Propulsion

NASA Technical Reports Server (NTRS)

Schmidt, George R.; Manzella, David H.; Kamhawi, Hani; Kremic, Tibor; Oleson, Steven R.; Dankanich, John W.; Dudzinski, Leonard A.

2009-01-01

Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.

A carbon-13 and proton nuclear magnetic resonance study of some experimental referee broadened-specification /ERBS/ turbine fuels

NASA Technical Reports Server (NTRS)

Dalling, D. K.; Pugmire, R. J.

1982-01-01

Preliminary results of a nuclear magnetic resonance (NMR) spectroscopy study of alternative jet fuels are presented. A referee broadened-specification (ERBS) aviation turbine fuel, a mixture of 65 percent traditional kerosene with 35 percent hydrotreated catalytic gas oil (HCGO) containing 12.8 percent hydrogen, and fuels of lower hydrogen content created by blending the latter with a mixture of HCGO and xylene bottoms were studied. The various samples were examined by carbon-13 and proton NMR at high field strength, and the resulting spectra are shown. In the proton spectrum of the 12.8 percent hydrogen fuel, no prominent single species is seen while for the blending stock, many individual lines are apparent. The ERBS fuels were fractionated by high-performance liquid chromatography and the resulting fractions analyzed by NMR. The species found are identified.

Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus.

PubMed Central

Marciniak, R A; Garcia-Blanco, M A; Sharp, P A

1990-01-01

Human immunodeficiency virus type 1 RNAs contain a sequence, trans-activation-response (TAR) element, which is required for tat protein-mediated trans-activation of viral gene expression. We have identified a nuclear protein from extracts of HeLa cells that binds to the TAR element RNA in a sequence-specific manner. The binding of this 68-kDa polypeptide was detected by UV cross-linking proteins to TAR element RNA transcribed in vitro. Competition experiments were performed by using a partially purified preparation of the protein to quantify the relative binding affinities of TAR element RNA mutants. The binding affinity of the TAR mutants paralleled the reported ability of those mutants to support tat trans-activation in vivo. We propose that this cellular protein moderates TAR activity in vivo. Images PMID:2333305

A nuclear electric propulsion vehicle for planetary exploration

NASA Technical Reports Server (NTRS)

Pawlik, E. V.; Phillips, W. M.

1976-01-01

A study is currently underway at JPL to design a nuclear electric-propulsion vehicle capable of performing detailed exploration of the outer planets. Evaluation of the design indicates that it is also applicable to orbit raising. Primary emphasis is on the power subsystem. Work on the design of the power system, the mission rationale, and preliminary spacecraft design are summarized. A propulsion system at a 400-kWe power level with a specific weight goal of no more than 25-kg/kW was selected for this study. The results indicate that this goal can be realized along with compatibility with the shuttle launch-vehicle constraints.

Hyper-track selector nuclear emulsion readout system aimed at scanning an area of one thousand square meters

NASA Astrophysics Data System (ADS)

Yoshimoto, Masahiro; Nakano, Toshiyuki; Komatani, Ryosuke; Kawahara, Hiroaki

2017-10-01

Automatic nuclear emulsion readout systems have seen remarkable progress since the original idea was developed almost 40 years ago. After the success of its full application to a large-scale neutrino experiment, OPERA, a much faster readout system, the hyper-track selector (HTS), has been developed. HTS, which has an extremely wide-field objective lens, reached a scanning speed of 4700 cm^2/h, which is nearly 100 times faster than the previous system and therefore strongly promotes many new experimental projects. We will describe the concept, specifications, system structure, and achieved performance in this paper.

Graphite Microstructural Characterization Using Time-Domain and Correlation-Based Ultrasonics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spicer, James

Among techniques that have been used to determine elastic modulus in nuclear graphites, ultrasonic methods have enjoyed wide use and standards using contacting piezoelectric tranducers have been developed to ensure repeatability of these types of measurements. However, the use of couplants and the pressures used to effectively couple transducers to samples can bias measurements and produce results that are not wholly related to the properties of the graphite itself. In this work, we have investigated the use of laser ultrasonic methods for making elastic modulus measurements in nuclear graphites. These methods use laser-based transmitters and receivers to gather data andmore » do not require use of ultrasonic couplants or mechanical contact with the sample. As a result, information directly related to the elastic responses of graphite can be gathered even if the graphite is porous, brittle and compliant. In particular, we have demonstrated the use of laser ultrasonics for the determination of both Young’s modulus and shear modulus in a range of nuclear graphites including those that are being considered for use in future nuclear reactors. These results have been analyzed to assess the contributions of porosity and microcracking to the elastic responses of these graphites. Laser-based methods have also been used to assess the moduli of NBG-18 and IG-110 where samples of each grade were oxidized to produce specific changes in porosity. These data were used to develop new models for the elastic responses of nuclear graphites and these models have been used to infer specific changes in graphite microstructure that occur during oxidation that affect elastic modulus. Specifically, we show how ultrasonic measurements in oxidized graphites are consistent with nano/microscale oxidation processes where basal plane edges react more readily than basal plane surfaces. We have also shown the use of laser-based methods to perform shear-wave birefringence measurements and have shown how these measurements can be used to assess elastic anisotropy in nuclear graphites. Using models developed in this program, ultrasonic data were interpreted to extract orientation distribution coefficients that could be used to represent anisotropy in these materials. This demonstration showed the use of ultrasonic methods to quantify anisotropy and how these methods provide more detailed information than do measurements of thermal expansion – a technique commonly used for assessing anisotropy in nuclear graphites. Finally, we have employed laser-based, ultrasonic-correlation techniques in attempts to quantify aspects of graphite microstructure such as pore size and distribution. Results of these measurements indicate that additional work must be performed to make this ultrasonic approach viable for quantitative microstructural characterization.« less

DEVELOPMENT, INSTALLATION AND OPERATION OF THE MPC&A OPERATIONS MONITORING (MOM) SYSTEM AT THE JOINT INSTITUTE FOR NUCLEAR RESEARCH (JINR) DUBNA, RUSSIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kartashov,V.V.; Pratt,W.; Romanov, Y.A.

The Material Protection, Control and Accounting (MPC&A) Operations Monitoring (MOM) systems handling at the International Intergovernmental Organization - Joint Institute for Nuclear Research (JINR) is described in this paper. Category I nuclear material (plutonium and uranium) is used in JINR research reactors, facilities and for scientific and research activities. A monitoring system (MOM) was installed at JINR in April 2003. The system design was based on a vulnerability analysis, which took into account the specifics of the Institute. The design and installation of the MOM system was a collaborative effort between JINR, Brookhaven National Laboratory (BNL) and the U.S. Departmentmore » of Energy (DOE). Financial support was provided by DOE through BNL. The installed MOM system provides facility management with additional assurance that operations involving nuclear material (NM) are correctly followed by the facility personnel. The MOM system also provides additional confidence that the MPC&A systems continue to perform effectively.« less

Detection in subsurface air of radioxenon released from medical isotope production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Christine; Biegalski, Steven; Haas, Derek

Abstract Under the Comprehensive Nuclear-Test-Ban Treaty, an On-Site Inspection (OSI) may be conducted to clarify whether a nuclear explosion has been carried out in violation of Article I of the Treaty. A major component of an OSI is the measurement of subsurface gases in order to detect radioactive noble gases that are produced in a nuclear explosion, particularly radioxenon and radioargon. In order to better understand potential backgrounds of these gases, a sampling campaign was performed near Canadian Nuclear Laboratories in the Ottawa River Valley, a major source of environmental radioxenon. First of their kind measurements of atmospheric radioxenon imprintedmore » into the shallow subsurface from an atmospheric pressure driven force were made using current OSI techniques to measure both atmospheric and subsurface gas samples which were analyzed for radioxenon. These measurements indicate that under specific sampling conditions, on the order of one percent of the atmospheric radioxenon concentration may be measured via subsurface sampling.« less

Lightweight Damage Tolerant Radiators for In-Space Nuclear Electric Power and Propulsion

NASA Technical Reports Server (NTRS)

Craven, Paul; SanSoucie, Michael P.; Tomboulian, Briana; Rogers, Jan; Hyers, Robert

2014-01-01

Nuclear electric propulsion (NEP) is a promising option for high-speed in-space travel due to the high energy density of nuclear power sources and efficient electric thrusters. Advanced power conversion technologies for converting thermal energy from the reactor to electrical energy at high operating temperatures would benefit from lightweight, high temperature radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature and mass. An effort at the NASA Marshall Space Flight Center to show that woven high thermal conductivity carbon fiber mats can be used to replace standard metal and composite radiator fins to dissipate waste heat from NEP systems is ongoing. The goals of this effort are to demonstrate a proof of concept, to show that a significant improvement of specific power (power/mass) can be achieved, and to develop a thermal model with predictive capabilities. A description of this effort is presented.

Summary documentation of LASL nuclear data evaluations for ENDF/B-V

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, P.G.

1979-01-01

Summaries are presented of nuclear data evaluations performed at Los Alamos Scientific Laboratory (LASL) that will comprise part of Version V of the Evaluated Nuclear Data File, ENDF/B. A total of 18 general purpose evaluations of neutron-induced data are summarized, together with 6 summaries directed specifically at covariance data evaluations. The general purpose evaluation summaries cover the following isotopes: /sup 1 -3/H, /sup 3/ /sup 4/He, /sup 6/ /sup 7/Li, /sup 10/B, /sup 14/ /sup 15/N, /sup 16/O, /sup 27/Al, /sup 182/ /sup 183/ /sup 184/ /sup 186/W, /sup 233/U, and /sup 242/Pu. The covariance data summaries are given formore » /sup 1/H, /sup 6/Li, /sup 10/B, /sup 14/N, /sup 16/O, and /sup 27/Al. 28 figures.« less

Work history and radioprotection practices in relation to cancer incidence and mortality in US radiologic technologists performing nuclear medicine procedures.

PubMed

Bernier, Marie Odile; Doody, Michele M; Van Dyke, Miriam E; Villoing, Daphné; Alexander, Bruce H; Linet, Martha S; Kitahara, Cari M

2018-05-02

Technologists working in nuclear medicine (NM) are exposed to higher radiation doses than most other occupationally exposed populations. The aim of this study was to estimate the risk of cancer in NM technologists in relation to work history, procedures performed and radioprotection practices. From the US Radiologic Technologists cohort study, 72 755 radiologic technologists who completed a 2003-2005 questionnaire were followed for cancer mortality through 31 December 2012 and for cancer incidence through completion of a questionnaire in 2012-2013. Multivariable-adjusted models were used to estimate HRs for total cancer incidence and mortality by history of ever performing NM procedures and frequency of performing specific diagnostic or therapeutic NM procedures and associated radiation protection measures by decade. During follow-up (mean=7.5 years), 960 incident cancers and 425 cancer deaths were reported among the 22 360 technologists who worked with NM procedures. We observed no increased risk of cancer incidence (HR 0.96, 95% CI 0.89 to 1.04) or death (HR 1.05, 95% CI 0.93 to 1.19) among workers who ever performed NM procedures. HRs for cancer incidence but not mortality were higher for technologists who began performing therapeutic procedures in 1960 and later compared with the 1950s. Frequency of performing diagnostic or therapeutic NM procedures and use of radioprotection measures were not consistently associated with cancer risk. No clear associations were observed for specific cancers, but results were based on small numbers. Cancer incidence and mortality were not associated with NM work history practices, including greater frequency of procedures performed. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Radioactive waste isolation in salt: special advisory report on the status of the Office of Nuclear Waste Isolation's plans for repository performance assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ditmars, J.D.; Walbridge, E.W.; Rote, D.M.

1983-10-01

Repository performance assessment is analysis that identifies events and processes that might affect a repository system for isolation of radioactive waste, examines their effects on barriers to waste migration, and estimates the probabilities of their occurrence and their consequences. In 1983 Battelle Memorial Institute's Office of Nuclear Waste Isolation (ONWI) prepared two plans - one for performance assessment for a waste repository in salt and one for verification and validation of performance assessment technology. At the request of the US Department of Energy's Salt Repository Project Office (SRPO), Argonne National Laboratory reviewed those plans and prepared this report to advisemore » SRPO of specific areas where ONWI's plans for performance assessment might be improved. This report presents a framework for repository performance assessment that clearly identifies the relationships among the disposal problems, the processes underlying the problems, the tools for assessment (computer codes), and the data. In particular, the relationships among important processes and 26 model codes available to ONWI are indicated. A common suggestion for computer code verification and validation is the need for specific and unambiguous documentation of the results of performance assessment activities. A major portion of this report consists of status summaries of 27 model codes indicated as potentially useful by ONWI. The code summaries focus on three main areas: (1) the code's purpose, capabilities, and limitations; (2) status of the elements of documentation and review essential for code verification and validation; and (3) proposed application of the code for performance assessment of salt repository systems. 15 references, 6 figures, 4 tables.« less

Integrated Nuclear and Conventional Theater Warfare Simulation (INWARS) Level III Specifications. Volume III. Air Combat Modeling.

DTIC Science & Technology

1978-07-24

will include an implicit air function that will perform the air planning and requesting associated with the various headquarters. The decision structure...air headquarters (The ATAF/TAA) will be included in the CIC to perform the implementation of the decisions /goals of the C21 elements, 1-4...realistic fashion. Once the AMPs have been formed, the operational process of launching, mission implementation etc. is no longer keyed to the decision cycle

Status Report on the CEBAF IR and UV FELs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leemann, Christoph; Bisognano, Joseph; Douglas, David

1993-07-01

The CEBAF five pass recirculating, superconducting linac, being developed as a high power electron source for nuclear physics, is also an ideal FEL driver.The 45 MeV front end linac is presently operational with a CW (low peak current) nuclear physics gun and has met all CEBAF performance specifications including low emittance and energy spread (< 1 * 10^-4). Progress will be reported in commissioning.This experience leads to predictions of excellent FEL performance.Initial designs reported last year have been advanced.Using the output of a high charge DC photoemission gun under development with a 6 cm period wiggler produces kilowatt output powersmore » in the 3.6 to 17 micrometer range in the fundamental.Third harmonic operation extends IR performance down to 1.2 micrometer.Beam at energies up to 400 MeV from the first full CEBAF linac will interact in a similar but longer wiggler to yield kilowatt UV light production at wavelengths as short as 0.15 micrometers.Full power FEL« less

Advances in Geologic Disposal System Modeling and Application to Crystalline Rock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mariner, Paul E.; Stein, Emily R.; Frederick, Jennifer M.

The Used Fuel Disposition Campaign (UFDC) of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Fuel Cycle Technology (OFCT) is conducting research and development (R&D) on geologic disposal of used nuclear fuel (UNF) and high-level nuclear waste (HLW). Two of the high priorities for UFDC disposal R&D are design concept development and disposal system modeling (DOE 2011). These priorities are directly addressed in the UFDC Generic Disposal Systems Analysis (GDSA) work package, which is charged with developing a disposal system modeling and analysis capability for evaluating disposal system performance for nuclear waste in geologic mediamore » (e.g., salt, granite, clay, and deep borehole disposal). This report describes specific GDSA activities in fiscal year 2016 (FY 2016) toward the development of the enhanced disposal system modeling and analysis capability for geologic disposal of nuclear waste. The GDSA framework employs the PFLOTRAN thermal-hydrologic-chemical multi-physics code and the Dakota uncertainty sampling and propagation code. Each code is designed for massively-parallel processing in a high-performance computing (HPC) environment. Multi-physics representations in PFLOTRAN are used to simulate various coupled processes including heat flow, fluid flow, waste dissolution, radionuclide release, radionuclide decay and ingrowth, precipitation and dissolution of secondary phases, and radionuclide transport through engineered barriers and natural geologic barriers to the biosphere. Dakota is used to generate sets of representative realizations and to analyze parameter sensitivity.« less

Nuclear-specific AR-V7 Protein Localization is Necessary to Guide Treatment Selection in Metastatic Castration-resistant Prostate Cancer.

PubMed

Scher, Howard I; Graf, Ryon P; Schreiber, Nicole A; McLaughlin, Brigit; Lu, David; Louw, Jessica; Danila, Daniel C; Dugan, Lyndsey; Johnson, Ann; Heller, Glenn; Fleisher, Martin; Dittamore, Ryan

2017-06-01

Circulating tumor cells (CTCs) expressing AR-V7 protein localized to the nucleus (nuclear-specific) identify metastatic castration-resistant prostate cancer (mCRPC) patients with improved overall survival (OS) on taxane therapy relative to the androgen receptor signaling inhibitors (ARSi) abiraterone acetate, enzalutamide, and apalutamide. To evaluate if expanding the positivity criteria to include both nuclear and cytoplasmic AR-V7 localization ("nuclear-agnostic") identifies more patients who would benefit from a taxane over an ARSi. The study used a cross-sectional cohort. Between December 2012 and March 2015, 193 pretherapy blood samples, 191 of which were evaluable, were collected and processed from 161 unique mCRPC patients before starting a new line of systemic therapy for disease progression at the Memorial Sloan Kettering Cancer Center. The association between two AR-V7 scoring criteria, post-therapy prostate-specific antigen (PSA) change (PTPC) and OS following ARSi or taxane treatment, was explored. One criterion required nuclear-specific AR-V7 localization, and the other required an AR-V7 signal but was agnostic to protein localization in CTCs. Correlation of AR-V7 status to PTPC and OS was investigated. Relationships with survival were analyzed using multivariable Cox regression and log-rank analyses. A total of 34 (18%) samples were AR-V7-positive using nuclear-specific criteria, and 56 (29%) were AR-V7-positive using nuclear-agnostic criteria. Following ARSi treatment, none of the 16 nuclear-specific AR-V7-positive samples and six of the 32 (19%) nuclear-agnostic AR-V7-positive samples had ≥50% PTPC at 12 weeks. The strongest baseline factor influencing OS was the interaction between the presence of nuclear-specific AR-V7-positive CTCs and treatment with a taxane (hazard ratio 0.24, 95% confidence interval 0.078-0.79; p=0.019). This interaction was not significant when nuclear-agnostic criteria were used. To reliably inform treatment selection using an AR-V7 protein biomarker in CTCs, nuclear-specific localization is required. We analyzed outcomes for patients with metastatic castration-resistant prostate cancer on androgen receptor signaling inhibitors and standard chemotherapy. Patients with circulating tumor cells that had AR-V7 protein in the cellular nuclei were very likely to survive longer on taxane-based chemotherapy, and tests unable to distinguish where the protein is located in the cell are not as predictive of benefit. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Functional transferred DNA within extracellular vesicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Jin; Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Jiangsu Province; Wu, Gengze

Extracellular vesicles (EVs) are small membrane vesicles including exosomes and shedding vesicles that mediated a cell-to-cell communication. EVs are released from almost all cell types under both physiological and pathological conditions and incorporate nuclear and cytoplasmic molecules for intercellular delivery. Besides protein, mRNA, and microRNA of these molecules, as recent studies show, specific DNA are prominently packaged into EVs. It appears likely that some of exosomes or shedding vesicles, bearing nuclear molecules are released upon bubble-like blebs. Specific interaction of EVs with susceptible recipients performs the uptake of EVs into the target cells, discharging their cargo including nuclear and cytoplasmicmore » macromolecules into the cytosol. These findings expand the nucleic acid content of EVs to include increased levels of specific DNA. Thus, EVs contain a repertoire of genetic information available for horizontal gene transfer and potential use as blood biomarkers for cancer and atherosclerosis. In this review, the focus is on the characteristics, biological functions, and roles in diseases of DNA within EVs. - Highlights: • This review is focused on the DNA within EVs including its characteristics, biological functions, and roles in diseases. • It is clear that DNA within EVs might have important physiological and pathological roles in various diseases. • Knowledge in this area may provides us alternative methods for disease diagnosis or therapy in the future.« less

Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97

PubMed Central

Sonntag, Eric; Wagner, Sabrina; Strojan, Hanife; Wangen, Christina; Lenac Rovis, Tihana; Lisnic, Berislav; Jonjic, Stipan; Schlötzer-Schrehardt, Ursula; Marschall, Manfred

2018-01-01

The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC) that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV) capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction. PMID:29342872

Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97.

PubMed

Milbradt, Jens; Sonntag, Eric; Wagner, Sabrina; Strojan, Hanife; Wangen, Christina; Lenac Rovis, Tihana; Lisnic, Berislav; Jonjic, Stipan; Sticht, Heinrich; Britt, William J; Schlötzer-Schrehardt, Ursula; Marschall, Manfred

2018-01-13

The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC) that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV) capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction.

ASME Nuclear Crane Standards for Enhanced Crane Safety and Increased Profit

NASA Astrophysics Data System (ADS)

Parkhurst, Stephen N.

2000-01-01

The ASME NOG-1 standard, 'Rules for Construction of Overhead and Gantry Cranes', covers top running cranes for nuclear facilities; with the ASME NUM-1 standard, 'Rules for Construction of Cranes, Monorails, and Hoists', covering the single girder, underhung, wall and jib cranes, as well as the monorails and hoists. These two ASME nuclear crane standards provide criteria for designing, inspecting and testing overhead handling equipment with enhanced safety to meet the 'defense-in-depth' approach of the United States Nuclear Regulatory Commission (USNRC) documents NUREG 0554 and NUREG 0612. In addition to providing designs for enhanced safety, the ASME nuclear crane standards provide a basis for purchasing overhead handling equipment with standard safety features, based upon accepted engineering principles, and including performance and environmental parameters specific to nuclear facilities. The ASME NOG-1 and ASME NUM-1 standards not only provide enhanced safety for handling a critical load, but also increase profit by minimizing the possibility of load drops, by reducing cumbersome operating restrictions, and by providing the foundation for a sound licensing position. The ASME nuclear crane standards can also increase profit by providing the designs and information to help ensure that the right standard equipment is purchased. Additionally, the ASME nuclear crane standards can increase profit by providing designs and information to help address current issues, such as the qualification of nuclear plant cranes for making 'planned engineered lifts' for steam generator replacement and decommissioning.

An Overview of the Nuclear Electric Xenon Ion System (NEXIS) Activity

NASA Technical Reports Server (NTRS)

Randolph, Thomas M.; Polk, James E., Jr.

2004-01-01

The Nuclear Electric Xenon Ion System (NEXIS) research and development activity within NASA's Project Prometheus, was one of three proposals selected by NASA to develop thruster technologies for long life, high power, high specific impulse nuclear electric propulsion systems that would enable more robust and ambitious science exploration missions to the outer solar system. NEXIS technology represents a dramatic improvement in the state-of-the-art for ion propulsion and is designed to achieve propellant throughput capabilities >= 2000 kg and efficiencies >= 78% while increasing the thruster power to >= 20 kW and specific impulse to >= 6000 s. The NEXIS technology uses erosion resistant carbon-carbon grids, a graphite keeper, a new reservoir hollow cathode, a 65-cm diameter chamber masked to produce a 57-cm diameter ion beam, and a shared neutralizer architecture to achieve these goals. The accomplishments of the NEXIS activity so far include performance testing of a laboratory model thruster, successful completion of a proof of concept reservoir cathode 2000 hour wear test, structural and thermal analysis of a completed development model thruster design, fabrication of most of the development model piece parts, and the nearly complete vacuum facility modifications to allow long duration wear testing of high power ion thrusters.

Interim Reliability Evaluation Program: analysis of the Browns Ferry, Unit 1, nuclear plant. Main report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mays, S.E.; Poloski, J.P.; Sullivan, W.H.

1982-07-01

A probabilistic risk assessment (PRA) was made of the Browns Ferry, Unit 1, nuclear plant as part of the Nuclear Regulatory Commission's Interim Reliability Evaluation Program (IREP). Specific goals of the study were to identify the dominant contributors to core melt, develop a foundation for more extensive use of PRA methods, expand the cadre of experienced PRA practitioners, and apply procedures for extension of IREP analyses to other domestic light water reactors. Event tree and fault tree analyses were used to estimate the frequency of accident sequences initiated by transients and loss of coolant accidents. External events such as floods,more » fires, earthquakes, and sabotage were beyond the scope of this study and were, therefore, excluded. From these sequences, the dominant contributors to probable core melt frequency were chosen. Uncertainty and sensitivity analyses were performed on these sequences to better understand the limitations associated with the estimated sequence frequencies. Dominant sequences were grouped according to common containment failure modes and corresponding release categories on the basis of comparison with analyses of similar designs rather than on the basis of detailed plant-specific calculations.« less

Constraining Nuclear Weak Interactions in Astrophysics and New Many-Core Algorithms for Neuroevolution

NASA Astrophysics Data System (ADS)

Sullivan, Christopher James

Weak interactions involving atomic nuclei are critical components in a broad range of as- trophysical phenomenon. As allowed Gamow-Teller transitions are the primary path through which weak interactions in nuclei operate in astrophysical contexts, the constraint of these nuclear transitions is an important goal of nuclear astrophysics. In this work, the charged current nuclear weak interaction known as electron capture is studied in the context of stellar core-collapse supernovae (CCSNe). Specifically, the sensitivity of the core-collapse and early post-bounce phases of CCSNe to nuclear electron capture rates are examined. Electron capture rates are adjusted by factors consistent with uncer- tainties indicated by comparing theoretical rates to those deduced from charge-exchange and beta-decay measurements. With the aide of such sensitivity studies, the diverse role of electron capture on thousands of nuclear species is constrained to a few tens of nuclei near N 50 and A 80 which dictate the primary response of CCSNe to nuclear electron capture. As electron capture is shown to be a leading order uncertainty during the core-collapse phase of CCSNe, future experimental and theoretical efforts should seek to constrain the rates of nuclei in this region. Furthermore, neutral current neutrino-nuclear interactions in the tens-of-MeV energy range are important in a variety of astrophysical environments including core-collapse super- novae as well as in the synthesis of some of the solar systems rarest elements. Estimates for inelastic neutrino scattering on nuclei are also important for neutrino detector construction aimed at the detection of astrophysical neutrinos. Due to the small cross sections involved, direct measurements are rare and have only been performed on a few nuclei. For this rea- son, indirect measurements provide a unique opportunity to constrain the nuclear transition strength needed to infer inelastic neutrino-nucleus cross sections. Herein the (6Li, 6Li‧) inelastic scattering reaction at 100 MeV/u is shown to indirectly select the relevant transitions for inelastic neutrino-nucleus scattering. Specifically, the probes unique selectivity of isovector- spin transfer excitations (Delta S = 1, DeltaT = 1, DeltaTz = 0) is demonstrated, thereby allowing the extraction of Gamow-Teller transition strength in the inelastic channel. Finally, the development and performance of a newly established technique for the sub- field of artificial intelligence known as neuroevolution is described. While separate from the physics that is discussed, these algorithmic advancements seek to improve the adoption of machine learning in the scientific domain by enabling neuroevolution to take advantage of modern heterogeneous compute architectures. Because the evolution of neural network pop- ulations offloads the choice of specific details about the neural networks to an evolutionary search algorithm, neuroevolution can increase the accessibility of machine learning. However, the evolution of neural networks through parameter and structural space presents a novel di- vergence problem when mapping the evaluation of these networks to many-core architectures. The principal focus of the algorithm optimizations described herein are on improving the feed-forward evaluation time when tens-to-hundreds of thousands of heterogeneous neural networks are evaluated concurrently.

Conversion of Questionnaire Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Danny H; Elwood Jr, Robert H

During the survey, respondents are asked to provide qualitative answers (well, adequate, needs improvement) on how well material control and accountability (MC&A) functions are being performed. These responses can be used to develop failure probabilities for basic events performed during routine operation of the MC&A systems. The failure frequencies for individual events may be used to estimate total system effectiveness using a fault tree in a probabilistic risk analysis (PRA). Numeric risk values are required for the PRA fault tree calculations that are performed to evaluate system effectiveness. So, the performance ratings in the questionnaire must be converted to relativemore » risk values for all of the basic MC&A tasks performed in the facility. If a specific material protection, control, and accountability (MPC&A) task is being performed at the 'perfect' level, the task is considered to have a near zero risk of failure. If the task is performed at a less than perfect level, the deficiency in performance represents some risk of failure for the event. As the degree of deficiency in performance increases, the risk of failure increases. If a task that should be performed is not being performed, that task is in a state of failure. The failure probabilities of all basic events contribute to the total system risk. Conversion of questionnaire MPC&A system performance data to numeric values is a separate function from the process of completing the questionnaire. When specific questions in the questionnaire are answered, the focus is on correctly assessing and reporting, in an adjectival manner, the actual performance of the related MC&A function. Prior to conversion, consideration should not be given to the numeric value that will be assigned during the conversion process. In the conversion process, adjectival responses to questions on system performance are quantified based on a log normal scale typically used in human error analysis (see A.D. Swain and H.E. Guttmann, 'Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications,' NUREG/CR-1278). This conversion produces the basic event risk of failure values required for the fault tree calculations. The fault tree is a deductive logic structure that corresponds to the operational nuclear MC&A system at a nuclear facility. The conventional Delphi process is a time-honored approach commonly used in the risk assessment field to extract numerical values for the failure rates of actions or activities when statistically significant data is absent.« less

Organellar proteomics reveals hundreds of novel nuclear proteins in the malaria parasite Plasmodium falciparum

PubMed Central

2012-01-01

Background The post-genomic era of malaria research provided unprecedented insights into the biology of Plasmodium parasites. Due to the large evolutionary distance to model eukaryotes, however, we lack a profound understanding of many processes in Plasmodium biology. One example is the cell nucleus, which controls the parasite genome in a development- and cell cycle-specific manner through mostly unknown mechanisms. To study this important organelle in detail, we conducted an integrative analysis of the P. falciparum nuclear proteome. Results We combined high accuracy mass spectrometry and bioinformatic approaches to present for the first time an experimentally determined core nuclear proteome for P. falciparum. Besides a large number of factors implicated in known nuclear processes, one-third of all detected proteins carry no functional annotation, including many phylum- or genus-specific factors. Importantly, extensive experimental validation using 30 transgenic cell lines confirmed the high specificity of this inventory, and revealed distinct nuclear localization patterns of hitherto uncharacterized proteins. Further, our detailed analysis identified novel protein domains potentially implicated in gene transcription pathways, and sheds important new light on nuclear compartments and processes including regulatory complexes, the nucleolus, nuclear pores, and nuclear import pathways. Conclusion Our study provides comprehensive new insight into the biology of the Plasmodium nucleus and will serve as an important platform for dissecting general and parasite-specific nuclear processes in malaria parasites. Moreover, as the first nuclear proteome characterized in any protist organism, it will provide an important resource for studying evolutionary aspects of nuclear biology. PMID:23181666

The challenge of developing structural materials for fusion power systems

NASA Astrophysics Data System (ADS)

Bloom, Everett E.

1998-10-01

Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Central in the goal of designing a safe, environmentally benign, and economically competitive fusion power system is the requirement for high performance, low activation materials. The general performance requirements for such materials have been defined and it is clear that materials developed for other applications (e.g. aerospace, nuclear fission, fossil energy systems) will not fully meet the needs of fusion. Advanced materials, with composition and microstructure tailored to yield properties that will satisfy the specific requirements of fusion must be developed. The international fusion programs have made significant progress towards this goal. Compositional requirements for low activation lead to a focus of development efforts on silicon carbide composites, vanadium alloys, and advanced martensitic steels as candidate structural material systems. Control of impurities will be critically important in actually achieving low activation but this appears possible. Neutron irradiation produces significant changes in the mechanical and physical properties of each of these material systems raising feasibility questions and design limitations. A focus of the research and development effort is to understand these effects, and through the development of specific compositions and microstructures, produce materials with improved and adequate performance. Other areas of research that are synergistic with the development of radiation resistant materials include fabrication, joining technology, chemical compatibility with coolants and tritium breeders and specific questions relating to the unique characteristics of a given material (e.g. coatings to reduce gas permeation in SiC composites) or design concept (e.g. electrical insulator coatings for liquid metal concepts).

Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruce G. Schnitzler

Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selectedmore » over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse ({approx}900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal alloy fuel types were pursued. The primary and significantly larger Rover/NERVA program focused on graphite type fuels. Research, development, and testing of high temperature graphite fuels was conducted. Reactors and engines employing these fuels were designed, built, and ground tested. The GE-710 and ANL programs focused on an alternative ceramic-metallic 'cermet' fuel type consisting of UO2 (or UN) fuel embedded in a refractory metal matrix such as tungsten. The General Electric program examined closed loop concepts for space or terrestrial applications as well as open loop systems for direct nuclear thermal propulsion. Although a number of fast spectrum reactor and engine designs suitable for direct nuclear thermal propulsion were proposed and designed, none were built. This report summarizes status results of evaluations of small nuclear reactor designs suitable for direct nuclear thermal propulsion.« less

PWR steam generator chemical cleaning, Phase I. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rothstein, S.

1978-07-01

United Nuclear Industries (UNI) entered into a subcontract with Consolidated Edison Company of New York (Con Ed) on August 8, 1977, for the purpose of developing methods to chemically clean the secondary side tube to tube support crevices of the steam generators of Indian Point Nos. 1 and 2 PWR plants. This document represents the first reporting on activities performed for Phase I of this effort. Specifically, this report contains the results of a literature search performed by UNI for the purpose of determining state-of-the-art chemical solvents and methods for decontaminating nuclear reactor steam generators. The results of the searchmore » sought to accomplish two objectives: (1) identify solvents beyond those proposed at present by UNI and Con Ed for the test program, and (2) confirm the appropriateness of solvents and methods of decontamination currently in use by UNI.« less

A subset of FG-nucleoporins is necessary for efficient Msn5-mediated nuclear protein export

PubMed Central

Finn, Erin M.; DeRoo, Elise P.; Clement, George W.; Rao, Sheila; Kruse, Sarah E.; Kokanovich, Kate M.; Belanger, Kenneth D.

2013-01-01

The transport of proteins between the cytoplasm and nucleus requires interactions between soluble transport receptors (karyopherins) and phenylalanine-glycine (FG) repeat domains on nuclear pore complex proteins (nucleoporins). However, the role of specific FG repeat-containing nucleoporins in nuclear protein export has not been carefully investigated. We have developed a novel kinetic assay to investigate the relative export kinetics mediated by the karyopherin Msn5/Kap142 in yeast containing specific FG-Nup mutations. Using the Msn5 substrate Crz1 as a marker for Msn5-mediated protein export, we observe that deletions of NUP100 or NUP2 result in decreased rates of Crz1 export, while nup60Δ and nup42Δ mutants do not vary significantly from wild type. The decreased Msn5 export rate in nup100Δ was confirmed using Mig1-GFP as a transport substrate. A nup100ΔGLFG mutant shows defects in nuclear export kinetics similar to a nup100Δ deletion. Removal of FG-repeats from Nsp1 also decreases export kinetics, while a loss of Nup1 FXFGs does not. To confirm that our export data reflected functional differences in protein localization, we performed Crz1 transcription activation assays using a CDRE::LacZ reporter gene that is upregulated upon increased transcription activation by Crz1 in vivo. We observe that expression from this reporter increases in nup100ΔGLFG and nsp1ΔFGΔFXFG strains that exhibit decreased Crz1 export kinetics but resembles wild-type levels in nup1ΔFXFG strains that do not exhibit export defects. These data provide evidence that the export of Msn5 is likely mediated by a specific subset of FG-Nups and that the GLFG repeat domain of Nup100 is important for Msn5-mediated nuclear protein export. PMID:23295456

Genome-Nuclear Lamina Interactions Regulate Cardiac Stem Cell Lineage Restriction.

PubMed

Poleshko, Andrey; Shah, Parisha P; Gupta, Mudit; Babu, Apoorva; Morley, Michael P; Manderfield, Lauren J; Ifkovits, Jamie L; Calderon, Damelys; Aghajanian, Haig; Sierra-Pagán, Javier E; Sun, Zheng; Wang, Qiaohong; Li, Li; Dubois, Nicole C; Morrisey, Edward E; Lazar, Mitchell A; Smith, Cheryl L; Epstein, Jonathan A; Jain, Rajan

2017-10-19

Progenitor cells differentiate into specialized cell types through coordinated expression of lineage-specific genes and modification of complex chromatin configurations. We demonstrate that a histone deacetylase (Hdac3) organizes heterochromatin at the nuclear lamina during cardiac progenitor lineage restriction. Specification of cardiomyocytes is associated with reorganization of peripheral heterochromatin, and independent of deacetylase activity, Hdac3 tethers peripheral heterochromatin containing lineage-relevant genes to the nuclear lamina. Deletion of Hdac3 in cardiac progenitor cells releases genomic regions from the nuclear periphery, leading to precocious cardiac gene expression and differentiation into cardiomyocytes; in contrast, restricting Hdac3 to the nuclear periphery rescues myogenesis in progenitors otherwise lacking Hdac3. Our results suggest that availability of genomic regions for activation by lineage-specific factors is regulated in part through dynamic chromatin-nuclear lamina interactions and that competence of a progenitor cell to respond to differentiation signals may depend upon coordinated movement of responding gene loci away from the nuclear periphery. Copyright © 2017 Elsevier Inc. All rights reserved.

A combined gas cooled nuclear reactor and fuel cell cycle

NASA Astrophysics Data System (ADS)

Palmer, David J.

Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping to increase performance and reduce degradation of the fuel cell. It also provides the high temperature needed to efficiently produce hydrogen for the fuel cell. Moreover, the inclusion of a highly reliable and electrically independent fuel cell is particularly important as the ship will have the ability to divert large amounts of power from the propulsion system to energize high energy weapon pulse loads without disturbing vital parts of the C4ISR systems or control panels. Ultimately, the thesis shows that the combined cycle is mutually beneficial to each side of the cycle and overall critically needed for our future.

Analysis of RNA-Seq datasets reveals enrichment of tissue-specific splice variants for nuclear envelope proteins.

PubMed

Capitanchik, Charlotte; Dixon, Charles; Swanson, Selene K; Florens, Laurence; Kerr, Alastair R W; Schirmer, Eric C

2018-06-18

Nuclear envelopathies/laminopathies yield tissue-specific pathologies, yet arise from mutation of ubiquitously-expressed genes. One possible explanation of this tissue specificity is that tissue-specific partners become disrupted from larger complexes, but a little investigated alternate hypothesis is that the mutated proteins themselves have tissue-specific splice variants. Here, we analyze RNA-Seq datasets to identify muscle-specific splice variants of nuclear envelope genes that could be relevant to the study of laminopathies, particularly muscular dystrophies, that are not currently annotated in sequence databases. Notably, we found novel isoforms or tissue-specificity of isoforms for: Lap2, linked to cardiomyopathy; Nesprin 2, linked to Emery-Dreifuss muscular dystrophy and Lmo7, a regulator of the emerin gene that is linked to Emery-Dreifuss muscular dystrophy. Interestingly, the muscle-specific exon in Lmo7 is rich in serine phosphorylation motifs, suggesting an important regulatory function. Evidence for muscle-specific splice variants in non-nuclear envelope proteins linked to other muscular dystrophies was also found. Tissue-specific variants were also indicated for several nucleoporins including Nup54, Nup133, Nup153 and Nup358/RanBP2. We confirmed expression of novel Lmo7 and RanBP2 variants with RT-PCR and found that specific knockdown of the Lmo7 variant caused a reduction in myogenic index during mouse C2C12 myogenesis. Global analysis revealed an enrichment of tissue-specific splice variants for nuclear envelope proteins in general compared to the rest of the genome, suggesting that splice variants contribute to regulating its tissue-specific functions.

A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arsenault, Eric A.; Obenchain, Daniel A.; Blake, Thomas A.

2017-05-01

The first microwave study of 1-iodobutane, performed by Steinmetz et al.in 1977) led to the determination of the B + C parameter for the anti-anti­and gauche-anti-conformers. Nearly 40 years later, this reinvestigation of 1- iodobutane, by high-resolution microwave spectroscopy, led to the determina­tion of rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants (NQCCs), and nuclear-sp rotation constants belonging to both of the two previously mentioned conformers, in addition to the gauche­ gauche-conformer, which was observed in this frequency regime for the first time. Comparisons between the three conformers of 1-iodobutanc and other iodo- and bromoalkanes are made, specifically throughmore » an analysis of the nuclear quadrupole coupling constants belonging to the iodine and bromine atoms in the respective chemical environments.« less

Radiation shielding estimates for manned Mars space flight.

PubMed

Dudkin, V E; Kovalev, E E; Kolomensky, A V; Sakovich, V A; Semenov, V F; Demin, V P; Benton, E V

1992-01-01

In the analysis of the required radiation shielding protection of spacecraft during a Mars flight, specific effects of solar activity (SA) on the intensity of galactic and solar cosmic rays were taken into consideration. Three spaceflight periods were considered: (1) maximum SA; (2) minimum SA; and (3) intermediate SA, when intensities of both galactic and solar cosmic rays are moderately high. Scenarios of spaceflights utilizing liquid-propellant rocket engines, low- and intermediate-thrust nuclear electrojet engines, and nuclear rocket engines, all of which have been designed in the Soviet Union, are reviewed. Calculations were performed on the basis of a set of standards for radiation protection approved by the U.S.S.R. State Committee for Standards. It was found that the lowest estimated mass of a Mars spacecraft, including the radiation shielding mass, obtained using a combination of a liquid propellant engine with low and intermediate thrust nuclear electrojet engines, would be 500-550 metric tons.

Evaluation of critical nuclear power plant electrical cable response to severe thermal fire conditions

NASA Astrophysics Data System (ADS)

Taylor, Gabriel James

The failure of electrical cables exposed to severe thermal fire conditions are a safety concern for operating commercial nuclear power plants (NPPs). The Nuclear Regulatory Commission (NRC) has promoted the use of risk-informed and performance-based methods for fire protection which resulted in a need to develop realistic methods to quantify the risk of fire to NPP safety. Recent electrical cable testing has been conducted to provide empirical data on the failure modes and likelihood of fire-induced damage. This thesis evaluated numerous aspects of the data. Circuit characteristics affecting fire-induced electrical cable failure modes have been evaluated. In addition, thermal failure temperatures corresponding to cable functional failures have been evaluated to develop realistic single point thermal failure thresholds and probability distributions for specific cable insulation types. Finally, the data was used to evaluate the prediction capabilities of a one-dimension conductive heat transfer model used to predict cable failure.

Investigation of applications for high-power, self-critical fissioning uranium plasma reactors

NASA Technical Reports Server (NTRS)

Rodgers, R. J.; Latham, T. S.; Krascella, N. L.

1976-01-01

Analytical studies were conducted to investigate potentially attractive applications for gaseous nuclear cavity reactors fueled by uranium hexafluoride and its decomposition products at temperatures of 2000 to 6000 K and total pressures of a few hundred atmospheres. Approximate operating conditions and performance levels for a class of nuclear reactors in which fission energy removal is accomplished principally by radiant heat transfer from the high temperature gaseous nuclear fuel to surrounding absorbing media were determined. The results show the radiant energy deposited in the absorbing media may be efficiently utilized in energy conversion system applications which include (1) a primary energy source for high thrust, high specific impulse space propulsion, (2) an energy source for highly efficient generation of electricity, and (3) a source of high intensity photon flux for heating working fluid gases for hydrogen production or MHD power extraction.

A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy

DOE PAGES

Arsenault, Eric A.; Obenchain, Daniel A.; Blake, Thomas A.; ...

2017-05-01

The first microwave study of 1-iodobutane, performed by Steinmetz et al. in 1977, led to the determination of the B+C parameter for the anti-anti- and gauche-anti-conformers. Nearly 40 years later, in this paper this reinvestigation of 1-iodobutane, by high-resolution microwave spectroscopy, led to the determination of rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants (NQCCs), and nuclear-spin rotation constants belonging to both of the two previously mentioned conformers, in addition to the gauche-gauche-conformer, which was observed in this frequency regime for the first time. Finally, comparisons between the three conformers of 1-iodobutane and other iodo- and bromoalkanes are made,more » specifically through an analysis of the nuclear quadrupole coupling constants belonging to the iodine and bromine atoms in the respective chemical environments.« less

Automations influence on nuclear power plants: a look at three accidents and how automation played a role.

PubMed

Schmitt, Kara

2012-01-01

Nuclear power is one of the ways that we can design an efficient sustainable future. Automation is the primary system used to assist operators in the task of monitoring and controlling nuclear power plants (NPP). Automation performs tasks such as assessing the status of the plant's operations as well as making real time life critical situational specific decisions. While the advantages and disadvantages of automation are well studied in variety of domains, accidents remind us that there is still vulnerability to unknown variables. This paper will look at the effects of automation within three NPP accidents and incidents and will consider why automation failed in preventing these accidents from occurring. It will also review the accidents at the Three Mile Island, Chernobyl, and Fukushima Daiichi NPP's in order to determine where better use of automation could have resulted in a more desirable outcome.

Selective nuclear export of specific classes of mRNA from mammalian nuclei is promoted by GANP

PubMed Central

Wickramasinghe, Vihandha O.; Andrews, Robert; Ellis, Peter; Langford, Cordelia; Gurdon, John B.; Stewart, Murray; Venkitaraman, Ashok R.; Laskey, Ronald A.

2014-01-01

The nuclear phase of the gene expression pathway culminates in the export of mature messenger RNAs (mRNAs) to the cytoplasm through nuclear pore complexes. GANP (germinal- centre associated nuclear protein) promotes the transfer of mRNAs bound to the transport factor NXF1 to nuclear pore complexes. Here, we demonstrate that GANP, subunit of the TRanscription-EXport-2 (TREX-2) mRNA export complex, promotes selective nuclear export of a specific subset of mRNAs whose transport depends on NXF1. Genome-wide gene expression profiling showed that half of the transcripts whose nuclear export was impaired following NXF1 depletion also showed reduced export when GANP was depleted. GANP-dependent transcripts were highly expressed, yet short-lived, and were highly enriched in those encoding central components of the gene expression machinery such as RNA synthesis and processing factors. After injection into Xenopus oocyte nuclei, representative GANP-dependent transcripts showed faster nuclear export kinetics than representative transcripts that were not influenced by GANP depletion. We propose that GANP promotes the nuclear export of specific classes of mRNAs that may facilitate rapid changes in gene expression. PMID:24510098

Mouse CCDC79 (TERB1) is a meiosis-specific telomere associated protein.

PubMed

Daniel, Katrin; Tränkner, Daniel; Wojtasz, Lukasz; Shibuya, Hiroki; Watanabe, Yoshinori; Alsheimer, Manfred; Tóth, Attila

2014-05-22

Telomeres have crucial meiosis-specific roles in the orderly reduction of chromosome numbers and in ensuring the integrity of the genome during meiosis. One such role is the attachment of telomeres to trans-nuclear envelope protein complexes that connect telomeres to motor proteins in the cytoplasm. These trans-nuclear envelope connections between telomeres and cytoplasmic motor proteins permit the active movement of telomeres and chromosomes during the first meiotic prophase. Movements of chromosomes/telomeres facilitate the meiotic recombination process, and allow high fidelity pairing of homologous chromosomes. Pairing of homologous chromosomes is a prerequisite for their correct segregation during the first meiotic division. Although inner-nuclear envelope proteins, such as SUN1 and potentially SUN2, are known to bind and recruit meiotic telomeres, these proteins are not meiosis-specific, therefore cannot solely account for telomere-nuclear envelope attachment and/or for other meiosis-specific characteristics of telomeres in mammals. We identify CCDC79, alternatively named TERB1, as a meiosis-specific protein that localizes to telomeres from leptotene to diplotene stages of the first meiotic prophase. CCDC79 and SUN1 associate with telomeres almost concurrently at the onset of prophase, indicating a possible role for CCDC79 in telomere-nuclear envelope interactions and/or telomere movements. Consistent with this scenario, CCDC79 is missing from most telomeres that fail to connect to SUN1 protein in spermatocytes lacking the meiosis-specific cohesin SMC1B. SMC1B-deficient spermatocytes display both reduced efficiency in telomere-nuclear envelope attachment and reduced stability of telomeres specifically during meiotic prophase. Importantly, CCDC79 associates with telomeres in SUN1-deficient spermatocytes, which strongly indicates that localization of CCDC79 to telomeres does not require telomere-nuclear envelope attachment. CCDC79 is a meiosis-specific telomere associated protein. Based on our findings we propose that CCDC79 plays a role in meiosis-specific telomere functions. In particular, we favour the possibility that CCDC79 is involved in telomere-nuclear envelope attachment and/or the stabilization of meiotic telomeres. These conclusions are consistent with the findings of an independently initiated study that analysed CCDC79/TERB1 functions.

Mouse CCDC79 (TERB1) is a meiosis-specific telomere associated protein

PubMed Central

2014-01-01

Background Telomeres have crucial meiosis-specific roles in the orderly reduction of chromosome numbers and in ensuring the integrity of the genome during meiosis. One such role is the attachment of telomeres to trans-nuclear envelope protein complexes that connect telomeres to motor proteins in the cytoplasm. These trans-nuclear envelope connections between telomeres and cytoplasmic motor proteins permit the active movement of telomeres and chromosomes during the first meiotic prophase. Movements of chromosomes/telomeres facilitate the meiotic recombination process, and allow high fidelity pairing of homologous chromosomes. Pairing of homologous chromosomes is a prerequisite for their correct segregation during the first meiotic division. Although inner-nuclear envelope proteins, such as SUN1 and potentially SUN2, are known to bind and recruit meiotic telomeres, these proteins are not meiosis-specific, therefore cannot solely account for telomere-nuclear envelope attachment and/or for other meiosis-specific characteristics of telomeres in mammals. Results We identify CCDC79, alternatively named TERB1, as a meiosis-specific protein that localizes to telomeres from leptotene to diplotene stages of the first meiotic prophase. CCDC79 and SUN1 associate with telomeres almost concurrently at the onset of prophase, indicating a possible role for CCDC79 in telomere-nuclear envelope interactions and/or telomere movements. Consistent with this scenario, CCDC79 is missing from most telomeres that fail to connect to SUN1 protein in spermatocytes lacking the meiosis-specific cohesin SMC1B. SMC1B-deficient spermatocytes display both reduced efficiency in telomere-nuclear envelope attachment and reduced stability of telomeres specifically during meiotic prophase. Importantly, CCDC79 associates with telomeres in SUN1-deficient spermatocytes, which strongly indicates that localization of CCDC79 to telomeres does not require telomere-nuclear envelope attachment. Conclusion CCDC79 is a meiosis-specific telomere associated protein. Based on our findings we propose that CCDC79 plays a role in meiosis-specific telomere functions. In particular, we favour the possibility that CCDC79 is involved in telomere-nuclear envelope attachment and/or the stabilization of meiotic telomeres. These conclusions are consistent with the findings of an independently initiated study that analysed CCDC79/TERB1 functions. PMID:24885367

Cell-free mitochondrial DNA copy number variation in head and neck squamous cell carcinoma: A study of non-invasive biomarker from Northeast India.

PubMed

Kumar, Manish; Srivastava, Shilpee; Singh, Seram Anil; Das, Anup Kumar; Das, Ganesh Chandra; Dhar, Bishal; Ghosh, Sankar Kumar; Mondal, Rosy

2017-10-01

Head and neck squamous cell carcinoma is the most commonly diagnosed cancer worldwide. The lifestyle, food habits, and customary practices manifest the Northeast Indian population toward higher susceptibility to develop head and neck squamous cell carcinoma. Here, we have investigated the association of smoke and smokeless tobacco, and alcohol with copy number variation of cell-free mitochondrial DNA and cell-free nuclear DNA in cases and controls. Cell-free DNA from plasma was isolated from 50 head and neck squamous cell carcinoma cases and 50 controls with informed written consent using QIAamp Circulating Nucleic Acid Kit. Real-time polymerase chain reaction was done for copy number variation in cell-free mitochondrial DNA and cell-free nuclear DNA. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic application between the two study groups using clinicopathological parameters. The levels of cell-free nuclear DNA and cell-free mitochondrial DNA of cases in association with smoke and smokeless tobacco, alcohol with smoking (p < 0.05) were significantly higher (p < 0.01 and p < 0.001, respectively) than controls. Using receiver operating characteristic curve analysis between head and neck squamous cell carcinoma cases and controls, we distinguished cell-free mitochondrial DNA (cutoff: 19.84 raw Ct; sensitivity: 84%; specificity: 100%; p < 0.001) and cell-free nuclear DNA (cutoff: 463,282 genomic equivalent/mL; sensitivity: 53%; specificity: 87%; p < 0.001). The copy number variation in cases (cell-free nuclear DNA: 5451.66 genomic equivalent/mL and cell-free mitochondrial DNA: 29,103,476.15 genomic equivalent/mL) and controls (cell-free nuclear DNA: 1650.9 genomic equivalent/mL and cell-free mitochondrial DNA: 9,189,312.54 genomic equivalent/mL), respectively. Our result indicates that the cell-free mitochondrial DNA content is highly associated with smoke and smokeless tobacco, betel quid chewing, and alcohol which shows greater promises, holding the key characteristics of diagnostic biomarkers, that is, minimal invasiveness, high specificity, and sensitivity.

A Nuclear Cryogenic Propulsion Stage for Near-Term Space Missions

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen E.; Adams, Robert B.; Bechtel, Ryan D.; Borowski, Stanley K.;

The Orphan Nuclear Receptor TLX/NR2E1 in Neural Stem Cells and Diseases.

PubMed

Wang, Tao; Xiong, Jian-Qiong

2016-02-01

The human TLX gene encodes an orphan nuclear receptor predominantly expressed in the central nervous system. Tailess and Tlx, the TLX homologues in Drosophila and mouse, play essential roles in body-pattern formation and neurogenesis during early embryogenesis and perform crucial functions in maintaining stemness and controlling the differentiation of adult neural stem cells in the central nervous system, especially the visual system. Multiple target genes and signaling pathways are regulated by TLX and its homologues in specific tissues during various developmental stages. This review aims to summarize previous studies including many recent updates from different aspects concerning TLX and its homologues in Drosophila and mouse.

Aging management guideline for commercial nuclear power plants - heat exchangers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Booker, S.; Lehnert, D.; Daavettila, N.

1994-06-01

This Aging Management Guideline (AMG) describes recommended methods for effective detection and mitigation of age-related degradation mechanisms in commercial nuclear power plant heat exchangers important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activitiesmore » to the more generic results and recommendations presented herein.« less

Nuclear emulsions for the detection of micrometric-scale fringe patterns: an application to positron interferometry

NASA Astrophysics Data System (ADS)

Aghion, S.; Ariga, A.; Bollani, M.; Ereditato, A.; Ferragut, R.; Giammarchi, M.; Lodari, M.; Pistillo, C.; Sala, S.; Scampoli, P.; Vladymyrov, M.

2018-05-01

Nuclear emulsions are capable of very high position resolution in the detection of ionizing particles. This feature can be exploited to directly resolve the micrometric-scale fringe pattern produced by a matter-wave interferometer for low energy positrons (in the 10–20 keV range). We have tested the performance of emulsion films in this specific scenario. Exploiting silicon nitride diffraction gratings as absorption masks, we produced periodic patterns with features comparable to the expected interferometer signal. Test samples with periodicities of 6, 7 and 20 μ m were exposed to the positron beam, and the patterns clearly reconstructed. Our results support the feasibility of matter-wave interferometry experiments with positrons.

Nuclear Electric Propulsion Application: RASC Mission Robotic Exploration of Venus

NASA Technical Reports Server (NTRS)

McGuire, Melissa L.; Borowski, Stanley K.; Packard, Thomas W.

2004-01-01

The following paper documents the mission and systems analysis portion of a study in which Nuclear Electric Propulsion (NEP) is used as the in-space transportation system to send a series of robotic rovers and atmospheric science airplanes to Venus in the 2020 to 2030 timeframe. As part of the NASA RASC (Revolutionary Aerospace Systems Concepts) program, this mission analysis is meant to identify future technologies and their application to far reaching NASA missions. The NEP systems and mission analysis is based largely on current technology state of the art assumptions. This study looks specifically at the performance of the NEP transfer stage when sending a series of different payload package point design options to Venus orbit.

GET: A generic electronics system for TPCs and nuclear physics instrumentation

NASA Astrophysics Data System (ADS)

Pollacco, E. C.; Grinyer, G. F.; Abu-Nimeh, F.; Ahn, T.; Anvar, S.; Arokiaraj, A.; Ayyad, Y.; Baba, H.; Babo, M.; Baron, P.; Bazin, D.; Beceiro-Novo, S.; Belkhiria, C.; Blaizot, M.; Blank, B.; Bradt, J.; Cardella, G.; Carpenter, L.; Ceruti, S.; De Filippo, E.; Delagnes, E.; De Luca, S.; De Witte, H.; Druillole, F.; Duclos, B.; Favela, F.; Fritsch, A.; Giovinazzo, J.; Gueye, C.; Isobe, T.; Hellmuth, P.; Huss, C.; Lachacinski, B.; Laffoley, A. T.; Lebertre, G.; Legeard, L.; Lynch, W. G.; Marchi, T.; Martina, L.; Maugeais, C.; Mittig, W.; Nalpas, L.; Pagano, E. V.; Pancin, J.; Poleshchuk, O.; Pedroza, J. L.; Pibernat, J.; Primault, S.; Raabe, R.; Raine, B.; Rebii, A.; Renaud, M.; Roger, T.; Roussel-Chomaz, P.; Russotto, P.; Saccà, G.; Saillant, F.; Sizun, P.; Suzuki, D.; Swartz, J. A.; Tizon, A.; Usher, N.; Wittwer, G.; Yang, J. C.

2018-04-01

General Electronics for TPCs (GET) is a generic, reconfigurable and comprehensive electronics and data-acquisition system for nuclear physics instrumentation of up to 33792 channels. The system consists of a custom-designed ASIC for signal processing, front-end cards that each house 4 ASIC chips and digitize the data in parallel through 12-bit ADCs, concentration boards to read and process the digital data from up to 16 ASICs, a 3-level trigger and master clock module to trigger the system and synchronize the data, as well as all of the associated firmware, communication and data-acquisition software. An overview of the system including its specifications and measured performances are presented.

Quantitative PET/CT scanner performance characterization based upon the society of nuclear medicine and molecular imaging clinical trials network oncology clinical simulator phantom.

PubMed

Sunderland, John J; Christian, Paul E

2015-01-01

The Clinical Trials Network (CTN) of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) operates a PET/CT phantom imaging program using the CTN's oncology clinical simulator phantom, designed to validate scanners at sites that wish to participate in oncology clinical trials. Since its inception in 2008, the CTN has collected 406 well-characterized phantom datasets from 237 scanners at 170 imaging sites covering the spectrum of commercially available PET/CT systems. The combined and collated phantom data describe a global profile of quantitative performance and variability of PET/CT data used in both clinical practice and clinical trials. Individual sites filled and imaged the CTN oncology PET phantom according to detailed instructions. Standard clinical reconstructions were requested and submitted. The phantom itself contains uniform regions suitable for scanner calibration assessment, lung fields, and 6 hot spheric lesions with diameters ranging from 7 to 20 mm at a 4:1 contrast ratio with primary background. The CTN Phantom Imaging Core evaluated the quality of the phantom fill and imaging and measured background standardized uptake values to assess scanner calibration and maximum standardized uptake values of all 6 lesions to review quantitative performance. Scanner make-and-model-specific measurements were pooled and then subdivided by reconstruction to create scanner-specific quantitative profiles. Different makes and models of scanners predictably demonstrated different quantitative performance profiles including, in some cases, small calibration bias. Differences in site-specific reconstruction parameters increased the quantitative variability among similar scanners, with postreconstruction smoothing filters being the most influential parameter. Quantitative assessment of this intrascanner variability over this large collection of phantom data gives, for the first time, estimates of reconstruction variance introduced into trials from allowing trial sites to use their preferred reconstruction methodologies. Predictably, time-of-flight-enabled scanners exhibited less size-based partial-volume bias than non-time-of-flight scanners. The CTN scanner validation experience over the past 5 y has generated a rich, well-curated phantom dataset from which PET/CT make-and-model and reconstruction-dependent quantitative behaviors were characterized for the purposes of understanding and estimating scanner-based variances in clinical trials. These results should make it possible to identify and recommend make-and-model-specific reconstruction strategies to minimize measurement variability in cancer clinical trials. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Contributions of the SCK.CEN Academy to education and training in nuclear science and technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coeck, Michele

Thanks to its thorough experience in the field of nuclear science and technology, its innovative research and the availability of large and unique nuclear installations, SCK.CEN is not only a renowned nuclear research institution, but also an important partner for nuclear education and training in Belgium as well as at international level. Within the SCK.CEN Academy, more than 60 years of nuclear expertise and experience gained from our different research projects is collected and transferred. In the interest of maintaining a competent workforce in industry, Healthcare, research, and policy, and of transferring nuclear knowledge and skills to the next generations,more » the SCK.CEN Academy takes it as its mission to: - provide guidance for students and early-stage researchers; - organize academic courses and customized training for professionals; - offer policy support with regard to education and training matters; - care for critical-intellectual capacities for society. Specifically in the domain of nuclear instrumentation the SCK.CEN Academy provides an opportunity to students at Bachelor, Master and PhD level to make use of the SCK.CEN infrastructure to support their thesis research or to perform an internship with the aim to improve and extend their knowledge and skills in a specific research or technical domain. Further, they can contribute to new findings in the field of nuclear instrumentation. The students are guided by our scientists, engineers and technicians who have years of experience in the relevant field. In addition, the SCK.CEN Academy contributes to traditional university education programs and delivers courses in several nuclear topics such as dosimetry. We also coordinate the Belgian Nuclear higher Engineering Network (BNEN), a one year (60 ECTS) master-after-master specialization in nuclear engineering in which 6 Belgian universities and SCK.CEN are involved. Beyond the contributions to academic education, we also provide several customized training programs tailored to the needs of the learners in terms of content, duration, level, language, location, etc. Complementary to the theoretical classes, ample attention is given to practical sessions and technical visits are foreseen which enable trainees to enrich and illustrate their acquired knowledge with the practice of real-life situations. In this poster presentation an overview will be given of the activities in the domains described above. Moreover it will be shown how these initiatives are embedded in the most recent European approaches to nuclear education and training via collaboration in several EU projects and networks. (authors)« less

14C content in vegetation in the vicinities of Brazilian nuclear power reactors.

PubMed

Dias, Cíntia Melazo; Santos, Roberto Ventura; Stenström, Kristina; Nícoli, Iêda Gomes; Skog, Göran; da Silveira Corrêa, Rosangela

2008-07-01

(14)C specific activities were measured in grass samples collected around Brazilian nuclear power reactors. The specific activity values varied between 227 and 299 Bq/kg C. Except for two samples which showed (14)C specific activities 22% above background values, half of the samples showed background specific activities, and the other half had a (14)C excess of 1-18%. The highest specific activities were found close to the nuclear power plants and along the main wind directions (NE and NNE). The activity values were found to decrease with increasing distance from the reactors. The unexpectedly high (14)C excess values found in two samples were related to the local topography, which favors (14)C accumulation and limits the dispersion of the plume. The results indicate a clear (14)C anthropogenic signal within 5 km around the nuclear power plants which is most prominent along northeastwards, the prevailing wind direction.

Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images*

PubMed Central

Botta, F; Mairani, A; Hobbs, R F; Vergara Gil, A; Pacilio, M; Parodi, K; Cremonesi, M; Coca Pérez, M A; Di Dia, A; Ferrari, M; Guerriero, F; Battistoni, G; Pedroli, G; Paganelli, G; Torres Aroche, L A; Sgouros, G

2014-01-01

Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 108 primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3–4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image-based dosimetry in nuclear medicine. PMID:24200697

United States Air Force Annual Financial Statement 2011

DTIC Science & Technology

2011-01-01

is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining...defenses. The B-52 Stratofortress is a long-range, nuclear and conventional heavy bomber that can perform a variety of missions. The bomber can fly...of the United States Government are deposited. Exceptions include receipts from specific sources required by law to be deposited into other

No Change of Body Mass, Fat Mass, and Skeletal Muscle Mass in Ultraendurance Swimmers after 12 Hours of Swimming

ERIC Educational Resources Information Center

Knechtle, Beat; Knechtle, Patrizia; Kaul, Rene; Kohler, Gotz

2009-01-01

We evaluated whether ultraendurance swimmers suffer a change of body mass, fat mass, skeletal muscle mass, total body water, and specific gravity of urine during a 12-hr swim in 12 male Caucasian ultraswimmers. Proton nuclear magnetic resonance of urine samples before and after the race was performed to detect alanine, lactate, and…

Assessment of RANS and LES Turbulence Modeling for Buoyancy-Aided/Opposed Forced and Mixed Convection

NASA Astrophysics Data System (ADS)

Clifford, Corey; Kimber, Mark

2017-11-01

Over the last 30 years, an industry-wide shift within the nuclear community has led to increased utilization of computational fluid dynamics (CFD) to supplement nuclear reactor safety analyses. One such area that is of particular interest to the nuclear community, specifically to those performing loss-of-flow accident (LOFA) analyses for next-generation very-high temperature reactors (VHTR), is the capacity of current computational models to predict heat transfer across a wide range of buoyancy conditions. In the present investigation, a critical evaluation of Reynolds-averaged Navier-Stokes (RANS) and large-eddy simulation (LES) turbulence modeling techniques is conducted based on CFD validation data collected from the Rotatable Buoyancy Tunnel (RoBuT) at Utah State University. Four different experimental flow conditions are investigated: (1) buoyancy-aided forced convection; (2) buoyancy-opposed forced convection; (3) buoyancy-aided mixed convection; (4) buoyancy-opposed mixed convection. Overall, good agreement is found for both forced convection-dominated scenarios, but an overly-diffusive prediction of the normal Reynolds stress is observed for the RANS-based turbulence models. Low-Reynolds number RANS models perform adequately for mixed convection, while higher-order RANS approaches underestimate the influence of buoyancy on the production of turbulence.

Status Report on Scoping Reactor Physics and Sensitivity/Uncertainty Analysis of LR-0 Reactor Molten Salt Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas R.; Mueller, Donald E.; Patton, Bruce W.

2016-08-31

Experiments are being planned at Research Centre Rež (RC Rež) to use the FLiBe (2 7LiF-BeF 2) salt from the Molten Salt Reactor Experiment (MSRE) to perform reactor physics measurements in the LR-0 low power nuclear reactor. These experiments are intended to inform on neutron spectral effects and nuclear data uncertainties for advanced reactor systems utilizing FLiBe salt in a thermal neutron energy spectrum. Oak Ridge National Laboratory (ORNL) is performing sensitivity/uncertainty (S/U) analysis of these planned experiments as part of the ongoing collaboration between the United States and the Czech Republic on civilian nuclear energy research and development. Themore » objective of these analyses is to produce the sensitivity of neutron multiplication to cross section data on an energy-dependent basis for specific nuclides. This report provides a status update on the S/U analyses of critical experiments at the LR-0 Reactor relevant to fluoride salt-cooled high temperature reactor (FHR) and liquid-fueled molten salt reactor (MSR) concepts. The S/U analyses will be used to inform design of FLiBe-based experiments using the salt from MSRE.« less

Stochastic analog neutron transport with TRIPOLI-4 and FREYA: Bayesian uncertainty quantification for neutron multiplicity counting

DOE PAGES

Verbeke, J. M.; Petit, O.

2016-06-01

From nuclear safeguards to homeland security applications, the need for the better modeling of nuclear interactions has grown over the past decades. Current Monte Carlo radiation transport codes compute average quantities with great accuracy and performance; however, performance and averaging come at the price of limited interaction-by-interaction modeling. These codes often lack the capability of modeling interactions exactly: for a given collision, energy is not conserved, energies of emitted particles are uncorrelated, and multiplicities of prompt fission neutrons and photons are uncorrelated. Many modern applications require more exclusive quantities than averages, such as the fluctuations in certain observables (e.g., themore » neutron multiplicity) and correlations between neutrons and photons. In an effort to meet this need, the radiation transport Monte Carlo code TRIPOLI-4® was modified to provide a specific mode that models nuclear interactions in a full analog way, replicating as much as possible the underlying physical process. Furthermore, the computational model FREYA (Fission Reaction Event Yield Algorithm) was coupled with TRIPOLI-4 to model complete fission events. As a result, FREYA automatically includes fluctuations as well as correlations resulting from conservation of energy and momentum.« less

A performance comparison of nuclear electric and nuclear thermal propulsion for Mars cargo missions across the 15-17 year synodic cycle

NASA Technical Reports Server (NTRS)

Sponaugle, Steven J.; Davis, Steven F.; Everett, Shonn F.

1992-01-01

This paper examines the effects of the Earth-Mars synodic cycle on Mars cargo missions. Cargo vehicles that use nuclear thermal propulsion are compared with those that use nuclear electric propulsion. It will be shown that for low energy class cargo missions, nuclear electric systems exhibit far less variation in peak performance over the synodic cycle than comparable nuclear thermal systems. Performance is measured by the amount of usable mass delivered to Mars, as well as the initial mass requirements in nuclear safe orbit. Nuclear electric propulsion systems also have significantly longer injection window opportunities for a given 26 month synodic period, resulting in much greater mission design flexibility. Injection window opportunities over a 20 year period from 2010 to 2030 are examined. This covers a complete synodic cycle and shows its effects on performance for Mars cargo missions.

The Race Against Nuclear Terror

DTIC Science & Technology

2005-09-01

orientation (central planning vs . market economy); or (3) systemic or state-specific incentives, such as new norms, emerge that diminish the appeal of... franchised version of the nuclear “Wal-Mart” cannot be discounted. Yet, if we are 49 Christopher Clary. “Dr... independent capability. To do so would require specific enrichment technology developed indigenously or obtained illegally. Most exporters of nuclear

SUPPORTING THE INDUSTRY BY DEVELOPING A DESIGN GUIDANCE FOR COMPUTER-BASED PROCEDURES FOR FIELD WORKERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oxstrand, Johanna; LeBlanc, Katya

The paper-based procedures currently used for nearly all activities in the commercial nuclear power industry have a long history of ensuring safe operation of the plants. However, there is potential to greatly increase efficiency and safety by improving how the human interacts with the procedures, which can be achieved through the use of computer-based procedures (CBPs). A CBP system offers a vast variety of improvements, such as context driven job aids, integrated human performance tools and dynamic step presentation. As a step toward the goal of improving procedure use performance, the U.S. Department of Energy Light Water Reactor Sustainability Programmore » researchers, together with the nuclear industry, have been investigating the possibility and feasibility of replacing current paper-based procedures with CBPs. The main purpose of the CBP research conducted at the Idaho National Laboratory was to provide design guidance to the nuclear industry to be used by both utilities and vendors. After studying existing design guidance for CBP systems, the researchers concluded that the majority of the existing guidance is intended for control room CBP systems, and does not necessarily address the challenges of designing CBP systems for instructions carried out in the field. Further, the guidance is often presented on a high level, which leaves the designer to interpret what is meant by the guidance and how to specifically implement it. The authors developed a design guidance to provide guidance specifically tailored to instructions that are carried out in the field based.« less

High Power Electric Propulsion System for NEP: Propulsion and Trajectory Options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koppel, Christophe R.; Duchemin, Olivier; Valentian, Dominique

Recent US initiatives in Nuclear Propulsion lend themselves naturally to raising the question of the assessment of various options and particularly to propose the High Power Electric Propulsion Subsystem (HPEPS) for the Nuclear Electric Propulsion (NEP). The purpose of this paper is to present the guidelines for the HPEPS with respect to the mission to Mars, for automatic probes as well as for manned missions. Among the various options, the technological options and the trajectory options are pointed out. The consequences of the increase of the electrical power of a thruster are first an increase of the thrust itself, butmore » also, as a general rule, an increase of the thruster performance due to its higher efficiency, particularly its specific impulse increase. The drawback is as a first parameter, the increase of the thruster's size, hence the so-called 'thrust density' shall be high enough or shall be drastically increased for ions thrusters. Due to the large mass of gas needed to perform the foreseen missions, the classical xenon rare gas is no more in competition, the total world production being limited to 20 -40 tons per year. Thus, the right selection of the propellant feeding the thruster is of prime importance. When choosing a propellant with lower molecular mass, the consequences at thruster level are an increase once more of the specific impulse, but at system level the dead mass may increase too, mainly because the increase of the mass of the propellant system tanks. Other alternatives, in rupture with respect to the current technologies, are presented in order to make the whole system more attractive. The paper presents a discussion on the thruster specific impulse increase that is sometime considered an increase of the main system performances parameter, but that induces for all electric propulsion systems drawbacks in the system power and mass design that are proportional to the thruster specific power increase (kW/N). The electric thruster specific impulse shall be optimized w.r.t. the mission. The trajectories taken into account in the paper are constrained by the allowable duration of the travel and the launcher size. The multi-arcs trajectories to Mars (using an optimized combination of chemical and Electric propulsion) are presented in detail. The compatibility with NEP systems that implies orbiting a sizeable nuclear reactor and a power generation system capable of converting thermal into electric power, with minimum mass and volumes fitting in with Ariane 5 or the Space Shuttle bay, is assessed.« less

Small unmanned aircraft system for remote contour mapping of a nuclear radiation field

NASA Astrophysics Data System (ADS)

Guss, Paul; McCall, Karen; Malchow, Russell; Fischer, Rick; Lukens, Michael; Adan, Mark; Park, Ki; Abbott, Roy; Howard, Michael; Wagner, Eric; Trainham, Clifford P.; Luke, Tanushree; Mukhopadhyay, Sanjoy; Oh, Paul; Brahmbhatt, Pareshkumar; Henderson, Eric; Han, Jinlu; Huang, Justin; Huang, Casey; Daniels, Jon

2017-09-01

For nuclear disasters involving radioactive contamination, small unmanned aircraft systems (sUASs) equipped with nuclear radiation detection and monitoring capability can be very important tools. Among the advantages of a sUAS are quick deployment, low-altitude flying that enhances sensitivity, wide area coverage, no radiation exposure health safety restriction, and the ability to access highly hazardous or radioactive areas. Additionally, the sUAS can be configured with the nuclear detecting sensor optimized to measure the radiation associated with the event. In this investigation, sUAS platforms were obtained for the installation of sensor payloads for radiation detection and electro-optical systems that were specifically developed for sUAS research, development, and operational testing. The sensor payloads were optimized for the contour mapping of a nuclear radiation field, which will result in a formula for low-cost sUAS platform operations with built-in formation flight control. Additional emphases of the investigation were to develop the relevant contouring algorithms; initiate the sUAS comprehensive testing using the Unmanned Systems, Inc. (USI) Sandstorm platforms and other acquired platforms; and both acquire and optimize the sensors for detection and localization. We demonstrated contour mapping through simulation and validated waypoint detection. We mounted a detector on a sUAS and operated it initially in the counts per second (cps) mode to perform field and flight tests to demonstrate that the equipment was functioning as designed. We performed ground truth measurements to determine the response of the detector as a function of source-to-detector distance. Operation of the radiation detector was tested using different unshielded sources.

Nuclear proteome analysis of undifferentiated mouse embryonic stem and germ cells.

PubMed

Buhr, Nicolas; Carapito, Christine; Schaeffer, Christine; Kieffer, Emmanuelle; Van Dorsselaer, Alain; Viville, Stéphane

2008-06-01

Embryonic stem cells (ESCs) and embryonic germ cells (EGCs) provide exciting models for understanding the underlying mechanisms that make a cell pluripotent. Indeed, such understanding would enable dedifferentiation and reprogrammation of any cell type from a patient needing a cell therapy treatment. Proteome analysis has emerged as an important technology for deciphering these biological processes and thereby ESC and EGC proteomes are increasingly studied. Nevertheless, their nuclear proteomes have only been poorly investigated up to now. In order to investigate signaling pathways potentially involved in pluripotency, proteomic analyses have been performed on mouse ESC and EGC nuclear proteins. Nuclei from ESCs and EGCs at undifferentiated stage were purified by subcellular fractionation. After 2-D separation, a subtractive strategy (subtracting culture environment contaminating spots) was applied and a comparison of ESC, (8.5 day post coïtum (dpc))-EGC and (11.5 dpc)-EGC specific nuclear proteomes was performed. A total of 33 ESC, 53 (8.5 dpc)-EGC, and 36 (11.5 dpc)-EGC spots were identified by MALDI-TOF-MS and/or nano-LC-MS/MS. This approach led to the identification of two isoforms (with and without N-terminal acetylation) of a known pluripotency marker, namely developmental pluripotency associated 5 (DPPA5), which has never been identified before in 2-D gel-MS studies of ESCs and EGCs. Furthermore, we demonstrated the efficiency of our subtracting strategy, in association with a nuclear subfractionation by the identification of a new protein (protein arginine N-methyltransferase 7; PRMT7) behaving as proteins involved in pluripotency.

10 CFR 54.15 - Specific exemptions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Specific exemptions. 54.15 Section 54.15 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) REQUIREMENTS FOR RENEWAL OF OPERATING LICENSES FOR NUCLEAR POWER PLANTS General Provisions § 54.15 Specific exemptions. Exemptions from the requirements of this part may be...

SPOC Benchmark Case: SNRE Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vishal Patel; Michael Eades; Claude Russel Joyner II

The Small Nuclear Rocket Engine (SNRE) was modeled in the Center for Space Nuclear Research’s (CSNR) Space Propulsion Optimization Code (SPOC). SPOC aims to create nuclear thermal propulsion (NTP) geometries quickly to perform parametric studies on design spaces of historic and new NTP designs. The SNRE geometry was modeled in SPOC and a critical core with a reasonable amount of criticality margin was found. The fuel, tie-tubes, reflector, and control drum masses were predicted rather well. These are all very important for neutronics calculations so the active reactor geometries created with SPOC can continue to be trusted. Thermal calculations ofmore » the average and hot fuel channels agreed very well. The specific impulse calculations used historically and in SPOC disagree so mass flow rates and impulses differed. Modeling peripheral and power balance components that do not affect nuclear characteristics of the core is not a feature of SPOC and as such, these components should continue to be designed using other tools. A full paper detailing the available SNRE data and comparisons with SPOC outputs will be submitted as a follow-up to this abstract.« less

A Perspective on Coupled Multiscale Simulation and Validation in Nuclear Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. P. Short; D. Gaston; C. R. Stanek

2014-01-01

The field of nuclear materials encompasses numerous opportunities to address and ultimately solve longstanding industrial problems by improving the fundamental understanding of materials through the integration of experiments with multiscale modeling and high-performance simulation. A particularly noteworthy example is an ongoing study of axial power distortions in a nuclear reactor induced by corrosion deposits, known as CRUD (Chalk River unidentified deposits). We describe how progress is being made toward achieving scientific advances and technological solutions on two fronts. Specifically, the study of thermal conductivity of CRUD phases has augmented missing data as well as revealed new mechanisms. Additionally, the developmentmore » of a multiscale simulation framework shows potential for the validation of a new capability to predict the power distribution of a reactor, in effect direct evidence of technological impact. The material- and system-level challenges identified in the study of CRUD are similar to other well-known vexing problems in nuclear materials, such as irradiation accelerated corrosion, stress corrosion cracking, and void swelling; they all involve connecting materials science fundamentals at the atomistic- and mesoscales to technology challenges at the macroscale.« less

Lightweight Radiator for in Space Nuclear Electric Propulsion

NASA Technical Reports Server (NTRS)

Craven, Paul; Tomboulian, Briana; SanSoucie, Michael

2014-01-01

Nuclear electric propulsion (NEP) is a promising option for high-speed in-space travel due to the high energy density of nuclear fission power sources and efficient electric thrusters. Advanced power conversion technologies may require high operating temperatures and would benefit from lightweight radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Game-changing propulsion systems are often enabled by novel designs using advanced materials. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature, thermal conductivity, and mass. These properties combine to allow advances in operational efficiency and high temperature feasibility. An effort at the NASA Marshall Space Flight Center to show that woven high thermal conductivity carbon fiber mats can be used to replace standard metal and composite radiator fins to dissipate waste heat from NEP systems is ongoing. The goals of this effort are to demonstrate a proof of concept, to show that a significant improvement of specific power (power/mass) can be achieved, and to develop a thermal model with predictive capabilities making use of constrained input parameter space. A description of this effort is presented.

Structural materials for Gen-IV nuclear reactors: Challenges and opportunities

NASA Astrophysics Data System (ADS)

Murty, K. L.; Charit, I.

2008-12-01

Generation-IV reactor design concepts envisioned thus far cater toward a common goal of providing safer, longer lasting, proliferation-resistant and economically viable nuclear power plants. The foremost consideration in the successful development and deployment of Gen-IV reactor systems is the performance and reliability issues involving structural materials for both in-core and out-of-core applications. The structural materials need to endure much higher temperatures, higher neutron doses and extremely corrosive environment, which are beyond the experience of the current nuclear power plants. Materials under active consideration for use in different reactor components include various ferritic/martensitic steels, austenitic stainless steels, nickel-base superalloys, ceramics, composites, etc. This paper presents a summary of various Gen-IV reactor concepts, with emphasis on the structural materials issues depending on the specific application areas. This paper also discusses the challenges involved in using the existing materials under both service and off-normal conditions. Tasks become increasingly complex due to the operation of various fundamental phenomena like radiation-induced segregation, radiation-enhanced diffusion, precipitation, interactions between impurity elements and radiation-produced defects, swelling, helium generation and so forth. Further, high temperature capability (e.g. creep properties) of these materials is a critical, performance-limiting factor. It is demonstrated that novel alloy and microstructural design approaches coupled with new materials processing and fabrication techniques may mitigate the challenges, and the optimum system performance may be achieved under much demanding conditions.

Developing a Nuclear Grade of Alloy 617 for Gen IV Nuclear Energy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Weiju; Swindeman, Robert W; Santella, Michael L

2010-01-01

Alloy 617, an attractive material not particularly developed for nuclear use, is now being considered as a leading candidate alloy by several countries for applications in the Gen IV Nuclear Energy Systems. An extensive review of its existing data suggests that it would be beneficial to refine the alloy s specification to a nuclear grade for the intended Gen IV systems. In this paper, rationale for developing a nuclear grade of the alloy is first discussed through an analysis on existing data from various countries. Then initial experiments for refining the alloy specification are described. Preliminary results have suggested themore » feasibility of the refinement approach, as well as the possibility for achieving a desirable nuclear grade. Based on the results, further research activities are recommended.« less

Silencing by nuclear matrix attachment distinguishes cell-type specificity: association with increased proliferation capacity.

PubMed

Linnemann, Amelia K; Krawetz, Stephen A

2009-05-01

DNA loop organization by nuclear scaffold/matrix attachment is a key regulator of gene expression that may provide a means to modulate phenotype. We have previously shown that attachment of genes to the NaCl-isolated nuclear matrix correlates with their silencing in HeLa cells. In contrast, expressed genes were associated with the lithium 3,5-diiodosalicylate (LIS)-isolated nuclear scaffold. To define their role in determining phenotype matrix attached regions (MARs) on human chromosomes 14-18 were identified as a function of expression in a primary cell line. The locations of MARs in aortic adventitial fibroblast (AoAF) cells were very stable (r = 0.909) and 96% of genes attached at MARs are silent (P < 0.001). Approximately one-third of the genes uniquely expressed in AoAF cells were associated with the HeLa cell nuclear matrix and silenced. Comparatively, 81% were associated with the AoAF cell nuclear scaffold (P < 0.001) and expressed. This suggests that nuclear scaffold/matrix association mediates a portion of cell type-specific gene expression thereby modulating phenotype. Interestingly, nuclear matrix attachment and thus silencing of specific genes that regulate proliferation and maintain the integrity of the HeLa cell genome suggests that transformation may at least in part be achieved through aberrant nuclear matrix attachment.

Overexpression of the lamina proteins Lamin and Kugelkern induces specific ultrastructural alterations in the morphology of the nuclear envelope of intestinal stem cells and enterocytes.

PubMed

Petrovsky, Roman; Krohne, Georg; Großhans, Jörg

2018-03-01

The nuclear envelope has a stereotypic morphology consisting of a flat double layer of the inner and outer nuclear membrane, with interspersed nuclear pores. Underlying and tightly linked to the inner nuclear membrane is the nuclear lamina, a proteinous layer of intermediate filament proteins and associated proteins. Physiological, experimental or pathological alterations in the constitution of the lamina lead to changes in nuclear morphology, such as blebs and lobulations. It has so far remained unclear whether the morphological changes depend on the differentiation state and the specific lamina protein. Here we analysed the ultrastructural morphology of the nuclear envelope in intestinal stem cells and differentiated enterocytes in adult Drosophila flies, in which the proteins Lam, Kugelkern or a farnesylated variant of LamC were overexpressed. Surprisingly, we detected distinct morphological features specific for the respective protein. Lam induced envelopes with multiple layers of membrane and lamina, surrounding the whole nucleus whereas farnesylated LamC induced the formation of a thick fibrillary lamina. In contrast, Kugelkern induced single-layered and double-layered intranuclear membrane structures, which are likely be derived from infoldings of the inner nuclear membrane or of the double layer of the envelope. Copyright © 2018 Elsevier GmbH. All rights reserved.

Results from a Field Trial of the Radio Frequency Based Cylinder Accountability and Tracking System at the Global Nuclear Fuel Americas Fuel Fabrication Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, Peter; Laughter, Mark D; Martyn, Rose

The Cylinder Accountability and Tracking System (CATS) is a tool designed for use by the International Atomic Energy Agency (IAEA) to improve overall inspector efficiency through real-time unattended monitoring of cylinder movements, site specific rules-based event detection, and the capability to integrate many types of monitoring technologies. The system is based on the tracking of cylinder movements using (radio frequency) RF tags, and the collection of data, such as accountability weights, that can be associated with the cylinders. This presentation will cover the installation and evaluation of the CATS at the Global Nuclear Fuels (GNF) fuel fabrication facility in Wilmington,more » NC. This system was installed to evaluate its safeguards applicability, operational durability under operating conditions, and overall performance. An overview of the system design and elements specific to the GNF deployment will be presented along with lessons learned from the installation process and results from the field trial.« less

Differential Subcellular Localization of the Glucocorticoid Receptor in Distinct Neural Stem and Progenitor Populations of the Mouse Telencephalon In Vivo

PubMed Central

Tsiarli, Maria A.; Monaghan, A. Paula; DeFranco, Donald B.

2013-01-01

Glucocorticoids are given to pregnant women at risk for premature delivery to promote lung maturation. Despite reports of detrimental effects of glucocorticoids on telencephalic neural stem/progenitor cells (NSPCs), the regional and cellular expression of the glucocorticoid receptor (GR) in various NSPC populations in the intact brain has not been thoroughly assessed. Therefore in this study we performed a detailed analysis of GR protein expression in the developing mouse ventral and dorsal telencephalon in vivo. At embryonic day 11.5 (E11.5), the majority of Pax6-positive radial glial cells (RGCs) and Tbr2-positive intermediate progenitor cells (IPCs) expressed nuclear GR, while a small number of RGCs on the apical ventricular zone (aVZ), expressed cytoplasmic GR. However, on E13.5, the latter population of RGCs increased in size, whereas abventricular NSPCs and especially neurons of the cortical plate, expressed nuclear GR. In IPCs, GR was always nuclear. A similar expression profile was observed throughout the ventral telencephalon, hippocampus and olfactory bulb, with NSPCs of the aVZ primarily expressing cytoplasmic GR, while abventricular NSPCs and mature cells primarily expressed nuclear GR. Close to birth, nuclear GR accumulated within specific cortical areas such as layer V, the subplate and CA1 area of the hippocampus. In summary, our data show that GR protein is present in early NSPCs of the dorsal and ventral telencephalon at E11.5 and primarily occupies the nucleus. Moreover, our study suggests that the subcellular localization of the receptor may be subjected to region and neurodevelopmental stage-specific regulation. PMID:23751362

Differential subcellular localization of the glucocorticoid receptor in distinct neural stem and progenitor populations of the mouse telencephalon in vivo.

PubMed

Tsiarli, Maria A; Paula Monaghan, A; Defranco, Donald B

2013-07-26

Glucocorticoids are given to pregnant women at risk for premature delivery to promote lung maturation. Despite reports of detrimental effects of glucocorticoids on telencephalic neural stem/progenitor cells (NSPCs), the regional and cellular expressions of the glucocorticoid receptor (GR) in various NSPC populations in the intact brain have not been thoroughly assessed. Therefore in this study we performed a detailed analysis of GR protein expression in the developing mouse ventral and dorsal telencephalon in vivo. At embryonic day 11.5 (E11.5), the majority of Pax6-positive radial glial cells (RGCs) and Tbr2-positive intermediate progenitor cells (IPCs) expressed nuclear GR, while a small number of RGCs on the apical ventricular zone (aVZ), expressed cytoplasmic GR. However, on E13.5, the latter population of RGCs increased in size, whereas abventricular NSPCs and especially neurons of the cortical plate, expressed nuclear GR. In IPCs, GR was always nuclear. A similar expression profile was observed throughout the ventral telencephalon, hippocampus and olfactory bulb, with NSPCs of the aVZ primarily expressing cytoplasmic GR, while abventricular NSPCs and mature cells primarily expressed nuclear GR. Close to birth, nuclear GR accumulated within specific cortical areas such as layer V, the subplate and CA1 area of the hippocampus. In summary, our data show that GR protein is present in early NSPCs of the dorsal and ventral telencephalon at E11.5 and primarily occupies the nucleus. Moreover, our study suggests that the subcellular localization of the receptor may be subjected to region and neurodevelopmental stage-specific regulation. Copyright © 2013 Elsevier B.V. All rights reserved.

Indium phosphide solar cell research in the US: Comparison with nonphotovoltaic sources

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1989-01-01

Highlights of the InP solar cell research program are presented. Homojunction cells with AMO efficiences approaching 19 percent were demonstrated while 17 percent was achieved for indium tin oxide (ITO)/InP cells. The superior radiation resistance of these latter two cell configurations over both Si and GaAs were demonstrated. InP cells on board the LIPS III satellite show no degradation after more than a year in orbit. Computer modeling calculations were directed toward radiation damage predictions and the specification of concentrator cell parameters. Computed array specific powers, for a specific orbit, are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

Nuclear Technology Series. Course 16: Mechanical Component Characteristics and Specifications.

ERIC Educational Resources Information Center

Center for Occupational Research and Development, Inc., Waco, TX.

This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

78 FR 75579 - License Renewal Application for Grand Gulf Nuclear Station, Unit 1

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-12

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-416; NRC-2011-0262] License Renewal Application for Grand Gulf Nuclear Station, Unit 1 AGENCY: Nuclear Regulatory Commission. ACTION: Draft supplemental....S. Nuclear Regulatory Commission (NRC) is issuing for public comment a draft, plant-specific...

1L Mark-IV Target Design Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koehler, Paul E.

This presentation includes General Design Considerations; Current (Mark-III) Lower Tier; Mark-III Upper Tier; Performance Metrics; General Improvements for Material Science; General Improvements for Nuclear Science; Improving FOM for Nuclear Science; General Design Considerations Summary; Design Optimization Studies; Expected Mark-IV Performance: Material Science; Expected Mark-IV Performance: Nuclear Science (Disk); Mark IV Enables Much Wider Range of Nuclear-Science FOM Gains than Mark III; Mark-IV Performance Summary; Rod or Disk? Center or Real FOV?; and Project Cost and Schedule.

Anti-brain autoantibodies in the serum of schizophrenic patients: a case-control study.

PubMed

Margari, Francesco; Petruzzelli, Maria Giuseppina; Mianulli, Rossana; Toto, Maddalena; Pastore, Adriana; Bizzaro, Nicola; Tampoia, Marilina

2013-12-30

Schizophrenia is considered a neurodevelopmental disorder with a multifactorial pathogenesis where autoimmune factors may play a significant role. The aim of this study was to verify the presence of anti-brain autoantibodies in the serum of schizophrenic patients compared to healthy controls. Autoantibodies against brain were detected by the immunofluorescence method, utilizing sections of rat hippocampus and hypothalamus and of monkey cerebellum. Three different fluorescence patterns were observed, staining the nucleus-cytoplasm of neurons, the neuroendothelial of blood vessel and the neurofilaments. Search for other organ-specific and non organ-specific autoantibodies was performed in all sera by indirect immunofluorescence method, enzyme linked immunosorbent assay and chemiluminescence immunoassay. Results showed a significant association between schizophrenia and anti-brain autoantibodies against the neuroendothelium of blood vessel in hypothalamus, hippocampus and cerebellum; a significant nuclear and cytoplasmic staining of neurons was assessed only for the hippocampus. No other significant association was found, except between schizophrenia and anti-nuclear autoantibodies on HEp-2 cells. In conclusion, these results support the hypothesis of a significant association between schizophrenia and circulating anti-brain autoantibodies, suggesting a diffuse reactivity against the neuroendothelium of blood vessel and highlighting a nuclear and cytoplasmic staining of the neurons of hippocampus. © 2013 Published by Elsevier Ireland Ltd.

Criticality Safety Evaluation of Standard Criticality Safety Requirements #1-520 g Operations in PF-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamanaka, Alan Joseph Jr.

Guidance has been requested from the Nuclear Criticality Safety Division (NCSD) regarding processes that involve 520 grams of fissionable material or less. This Level-3 evaluation was conducted and documented in accordance with NCS-AP-004 (Ref. 1), formerly NCS-GUIDE-01. This evaluation is being written as a generic evaluation for all operations that will be able to operate using a 520-gram mass limit. Implementation for specific operations will be performed using a Level 1 CSED, which will confirm and document that this CSED can be used for the specific operation as discussed in NCS-MEMO-17-007 (Ref. 2). This Level 3 CSED updates and supersedesmore » the analysis performed in NCS-TECH-14-014 (Ref. 3).« less

A Nuclear Cryogenic Propulsion Stage for Near-Term Space Missions

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Adams, Robert B.; Bechtel, Ryan D.; Borowski, Stanley K.; George, Jeffrey A.

2013-01-01

Development efforts in the United States have demonstrated the viability and performance potential of NTP systems. For example, Project Rover (1955 - 1973) completed 22 high power rocket reactor tests. Peak performances included operating at an average hydrogen exhaust temperature of 2550 K and a peak fuel power density of 5200 MW/m3 (Pewee test), operating at a thrust of 930 kN (Phoebus-2A test), and operating for 62.7 minutes on a single burn (NRXA6 test). Results from Project Rover indicated that an NTP system with a high thrust-toweight ratio and a specific impulse greater than 900 s would be feasible. Excellent results have also been obtained by Russia. Ternary carbide fuels developed in Russia may have the potential for providing even higher specific impulses.

Automated analysis of cell migration and nuclear envelope rupture in confined environments.

PubMed

Elacqua, Joshua J; McGregor, Alexandra L; Lammerding, Jan

2018-01-01

Recent in vitro and in vivo studies have highlighted the importance of the cell nucleus in governing migration through confined environments. Microfluidic devices that mimic the narrow interstitial spaces of tissues have emerged as important tools to study cellular dynamics during confined migration, including the consequences of nuclear deformation and nuclear envelope rupture. However, while image acquisition can be automated on motorized microscopes, the analysis of the corresponding time-lapse sequences for nuclear transit through the pores and events such as nuclear envelope rupture currently requires manual analysis. In addition to being highly time-consuming, such manual analysis is susceptible to person-to-person variability. Studies that compare large numbers of cell types and conditions therefore require automated image analysis to achieve sufficiently high throughput. Here, we present an automated image analysis program to register microfluidic constrictions and perform image segmentation to detect individual cell nuclei. The MATLAB program tracks nuclear migration over time and records constriction-transit events, transit times, transit success rates, and nuclear envelope rupture. Such automation reduces the time required to analyze migration experiments from weeks to hours, and removes the variability that arises from different human analysts. Comparison with manual analysis confirmed that both constriction transit and nuclear envelope rupture were detected correctly and reliably, and the automated analysis results closely matched a manual analysis gold standard. Applying the program to specific biological examples, we demonstrate its ability to detect differences in nuclear transit time between cells with different levels of the nuclear envelope proteins lamin A/C, which govern nuclear deformability, and to detect an increase in nuclear envelope rupture duration in cells in which CHMP7, a protein involved in nuclear envelope repair, had been depleted. The program thus presents a versatile tool for the study of confined migration and its effect on the cell nucleus.

Detection of EEG electrodes in brain volumes.

PubMed

Graffigna, Juan P; Gómez, M Eugenia; Bustos, José J

2010-01-01

This paper presents a method to detect 128 EEG electrodes in image study and to merge with the Nuclear Magnetic Resonance volume for better diagnosis. First we propose three hypotheses to define a specific acquisition protocol in order to recognize the electrodes and to avoid distortions in the image. In the second instance we describe a method for segmenting the electrodes. Finally, registration is performed between volume of the electrodes and NMR.

Nuclear Thermal Propulsion: Past, Present, and a Look Ahead

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.

2014-01-01

NTR: High thrust high specific impulse (2 x LOXLH2 chemical) engine uses high power density fission reactor with enriched uranium fuel as thermal power source. Reactor heat is removed using H2 propellant which is then exhausted to produce thrust. Conventional chemical engine LH2 tanks, turbo pumps, regenerative nozzles and radiation-cooled shirt extensions used -- NTR is next evolutionary step in high performance liquid rocket engines.

Tissue Specific and Hormonal Regulation of Gene Expression

DTIC Science & Technology

1997-08-01

interference assays were performed. These assays identify DNA bases that, when modified, interfere with the binding of the nuclear factor to the hCRH promoter...thymidine residues. The DNA bases that when modified affected the binding of the protein are noted with arrows, and their location in the hCRH...indicated. B. Methylation interference. The fragments were partially methylated using dimethyl sulfate. The DNA bases that when modified affected the

SNPSAM - Space Nuclear Power System Analysis Model

NASA Astrophysics Data System (ADS)

El-Genk, Mohamed S.; Seo, Jong T.

The current version of SNPSAM is described, and the results of the integrated thermoeletric SP-100 system performance studies using SNPSAM are reported. The electric power output, conversion efficiency, coolant temperatures, and specific pumping power of the system are calculated as functions of the reactor thermal power and the liquid metal coolant type (Li or NaK-78) during steady state operation. The transient behavior of the system is also discussed.

Aging of Cloned Animals: A Mini-Review.

PubMed

Burgstaller, Jörg Patrick; Brem, Gottfried

2017-01-01

The number of species for which somatic cell nuclear transfer (SCNT) protocols are established is still increasing. Due to the high number of cloned farm, companion, and sport animals, the topic of animal cloning never ceases to be of public interest. Numerous studies cover the health status of SCNT-derived animals, but very few cover the effects of SCNT on aging. However, only cloned animals that reach the full extent of the species-specific lifespan, doing so with only the normal age-related afflictions and diseases, would prove that SCNT can produce completely healthy offspring. Here, we review the available literature and own data to answer the question whether the aging process of cloned animals is qualitatively different from normal animals. We focus on 4 main factors that were proposed to influence aging in these animals: epigenetic (dys)regulation, accumulation of damaged macromolecules, shortened telomeres, and (nuclear donor-derived) age-related DNA damage. We find that at least some cloned animals can reach the species-specific maximum age with a performance that matches that of normal animals. However, for most species, only anecdotal evidence of cloned animals reaching high age is available. We therefore encourage reports on the aging of cloned animals to make further analysis on the performance of SCNT possible. © 2016 S. Karger AG, Basel.

Game Imaging Meets Nuclear Reality

ScienceCinema

Michel, Kelly; Watkins, Adam

2018-01-16

At Los Alamos National Laboratory, a team of artists and animators, nuclear engineers and computer scientists is teaming to provide 3-D models of nuclear facilities to train IAEA safeguards inspectors and others who need fast familiarity with specific nuclear sites.

Standard specification for nuclear grade hafnium oxide pellets. ASTM standard

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This specification is under the jurisdiction of ASTM Committee C-26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.03 on Neutron Absorber Materials Specifications. Current edition approved May 10, 1997. Published May 1998. Originally published as C 1076-87. Last previous edition C 1076-92.

Development of a drone equipped with optimized sensors for nuclear and radiological risk characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boudergui, K.; Carrel, F.; Domenech, T.

2011-07-01

The MOBISIC project, funded by the Systematic Paris-Region cluster, is being developed in the context of local crisis (attack bombing in urban environment, in confined space such as an underground train tunnel etc.) or specific event securing (soccer world cup, political meeting etc.). It consists in conceiving, developing and experimenting a mobile, modular ('plug and play') and multi-sensors securing system. In this project, CEA LIST has suggested different solutions for nuclear risks detection and identification. It results in embedding a CZT sensor and a gamma camera in an indoor drone. This article first presents the different modifications carried out onmore » the UAV and different sensors, and focuses then on the experimental performances. (authors)« less

Electromagnetic radiation from nuclear collisions at ultrarelativistic energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turbide, Simon; Gale, Charles; Frodermann, Evan

2008-02-15

The hot and dense strongly interacting matter created in collisions of heavy nuclei at RHIC energies is modeled with relativistic hydrodynamics, and the spectra of real and virtual photons produced at midrapidity in these events are calculated. Several different sources are considered, and their relative importance is compared. Specifically, we include jet fragmentation, jet-plasma interactions, the emission of radiation from the thermal medium and from primordial hard collisions. Our calculations consistently take into account jet energy loss, as evaluated in the AMY formalism. We obtain results for the spectra, the nuclear modification factor (R{sub AA}{sup {gamma}}), and the azimuthal anisotropymore » (v{sub 2}{sup {gamma}}) that agree with the photon measurements performed by the PHENIX Collaboration at RHIC.« less

A Comparison Framework for Reactor Anti-Neutrino Detectors in Near-Field Nuclear Safeguards Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendenhall, M.; Bowden, N.; Brodsky, J.

Electron anti-neutrino ( e) detectors can support nuclear safeguards, from reactor monitoring to spent fuel characterization. In recent years, the scientific community has developed multiple detector concepts, many of which have been prototyped or deployed for specific measurements by their respective collaborations. However, the diversity of technical approaches, deployment conditions, and analysis techniques complicates direct performance comparison between designs. We have begun development of a simulation framework to compare and evaluate existing and proposed detector designs for nonproliferation applications in a uniform manner. This report demonstrates the intent and capabilities of the framework by evaluating four detector design concepts, calculatingmore » generic reactor antineutrino counting sensitivity, and capabilities in a plutonium disposition application example.« less

High-resolution nuclear magnetic resonance of superfluid 3B

NASA Astrophysics Data System (ADS)

Kycia, J. B.; Haard, T. M.; Rand, M. R.; Hensley, H. H.; Moores, G. F.; Lee, Y.; Hamot, P. J.; Sprague, D. T.; Halperin, W. P.; Thuneberg, E. V.

1994-02-01

High-resolution nuclear magnetic resonance measurements of bulk superfluid 3B have been performed at temperatures above 0.5 mK and at pressures from 0.3 to 21.7 bars. We have found that the resonance frequency is shifted from the Larmor frequency of the normal fluid. According to the theory of Greaves the shift at the superfluid transition determines a specific combination, β345, of the 5 fourth-order coefficients of the order parameter invariants used in the Ginzburg-Landau description of superfluid 3He. We found that β345 approaches the weak coupling limit at low pressure, and decreases at higher pressures qualitatively consistent with the theory of Sauls and Serene but in disagreement with the results of Tang et al.

Experiment of monitoring thermal discharge drained from nuclear plant through airborne infrared remote sensing

NASA Astrophysics Data System (ADS)

Wang, Difeng; Pan, Delu; Li, Ning

2009-07-01

The State Development and Planning Commission has approved nuclear power projects with the total capacity of 23,000 MW. The plants will be built in Zhejiang, Jiangsu, Guangdong, Shandong, Liaoning and Fujian Province before 2020. However, along with the nuclear power policy of accelerated development in our country, the quantity of nuclear plants and machine sets increases quickly. As a result the environment influence of thermal discharge will be a problem that can't be slid over. So evaluation of the environment influence and engineering simulation must be performed before station design and construction. Further more real-time monitoring of water temperature need to be arranged after fulfillment, reflecting variety of water temperature in time and provided to related managing department. Which will help to ensure the operation of nuclear plant would not result in excess environment breakage. At the end of 2007, an airborne thermal discharge monitoring experiment has been carried out by making use of MAMS, a marine multi-spectral scanner equipped on the China Marine Surveillance Force airplane. And experimental subject was sea area near Qin Shan nuclear plant. This paper introduces the related specification and function of MAMS instrument, and decrypts design and process of the airborne remote sensing experiment. Experiment showed that applying MAMS to monitoring thermal discharge is viable. The remote sensing on a base of thermal infrared monitoring technique told us that thermal discharge of Qin Shan nuclear plant was controlled in a small scope, never breaching national water quality standard.

Propulsion Research at the Propulsion Research Center of the NASA Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Blevins, John; Rodgers, Stephen

2003-01-01

The Propulsion Research Center of the NASA Marshall Space Flight Center is engaged in research activities aimed at providing the bases for fundamental advancement of a range of space propulsion technologies. There are four broad research themes. Advanced chemical propulsion studies focus on the detailed chemistry and transport processes for high-pressure combustion, and on the understanding and control of combustion stability. New high-energy propellant research ranges from theoretical prediction of new propellant properties through experimental characterization propellant performance, material interactions, aging properties, and ignition behavior. Another research area involves advanced nuclear electric propulsion with new robust and lightweight materials and with designs for advanced fuels. Nuclear electric propulsion systems are characterized using simulated nuclear systems, where the non-nuclear power source has the form and power input of a nuclear reactor. This permits detailed testing of nuclear propulsion systems in a non-nuclear environment. In-space propulsion research is focused primarily on high power plasma thruster work. New methods for achieving higher thrust in these devices are being studied theoretically and experimentally. Solar thermal propulsion research is also underway for in-space applications. The fourth of these research areas is advanced energetics. Specific research here includes the containment of ion clouds for extended periods. This is aimed at proving the concept of antimatter trapping and storage for use ultimately in propulsion applications. Another activity in this involves research into lightweight magnetic technology for space propulsion applications.

Pre-irradiation testing and analysis to support the LWRS Hybrid SiC-CMC-Zircaloy-04 unfueled rodlet irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isabella J van Rooyen

2012-09-01

Nuclear fuel performance is a significant driver of nuclear power plant operational performance, safety, economics and waste disposal requirements. The Advanced Light Water Reactor (LWR) Nuclear Fuel Development Pathway focuses on improving the scientific knowledge basis to enable the development of high-performance, high burn-up fuels with improved safety and cladding integrity and improved nuclear fuel cycle economics. To achieve significant improvements, fundamental changes are required in the areas of nuclear fuel composition, cladding integrity, and fuel/cladding interaction.

Pre-irradiation testing and analysis to support the LWRS Hybrid SiC-CMC-Zircaloy-04 unfueled rodlet irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isabella J van Rooyen

2013-01-01

Nuclear fuel performance is a significant driver of nuclear power plant operational performance, safety, economics and waste disposal requirements. The Advanced Light Water Reactor (LWR) Nuclear Fuel Development Pathway focuses on improving the scientific knowledge basis to enable the development of high-performance, high burn-up fuels with improved safety and cladding integrity and improved nuclear fuel cycle economics. To achieve significant improvements, fundamental changes are required in the areas of nuclear fuel composition, cladding integrity, and fuel/cladding interaction.

Non-Nuclear Testing of Space Nuclear Systems at NASA MSFC

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Pearson, Boise J.; Aschenbrenner, Kenneth C.; Bradley, David E.; Dickens, Ricky; Emrich, William J.; Garber, Anne; Godfroy, Thomas J.; Harper, Roger T.; Martin, Jim J.;

Three-dimensional analysis of nuclear heterochromatin distribution during early development in the rabbit.

PubMed

Bonnet-Garnier, Amélie; Kiêu, Kiên; Aguirre-Lavin, Tiphaine; Tar, Krisztina; Flores, Pierre; Liu, Zichuan; Peynot, Nathalie; Chebrout, Martine; Dinnyés, András; Duranthon, Véronique; Beaujean, Nathalie

2018-04-18

Changes to the spatial organization of specific chromatin domains such as constitutive heterochromatin have been studied extensively in somatic cells. During early embryonic development, drastic epigenetic reprogramming of both the maternal and paternal genomes, followed by chromatin remodeling at the time of embryonic genome activation (EGA), have been observed in the mouse. Very few studies have been performed in other mammalian species (human, bovine, or rabbit) and the data are far from complete. During this work, we studied the three-dimensional organization of pericentromeric regions during the preimplantation period in the rabbit using specific techniques (3D-FISH) and tools (semi-automated image analysis). We observed that the pericentromeric regions (identified with specific probes for Rsat I and Rsat II genomic sequences) changed their shapes (from pearl necklaces to clusters), their nuclear localizations (from central to peripheral), as from the 4-cell stage. This reorganization goes along with histone modification changes and reduced amount of interactions with nucleolar precursor body surface. Altogether, our results suggest that the 4-cell stage may be a crucial window for events necessary before major EGA, which occurs during the 8-cell stage in the rabbit.

Update on Common-Cause Failure Experience and Mitigation Practices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Richard Thomas; Muhlheim, Michael David; Pullum, Laura L

2014-04-01

Experience in other industries has shown that digital technology can provide substantial benefits in terms of performance and reliability. However, the U.S. nuclear power industry has been slow to adopt the technology extensively in its instrumentation and control (I&C) applications because of inhibiting factors such as regulatory uncertainty, insufficient technological experience base, implementation complexity, limited availability of nuclear-qualified products and vendors, and inadequate definition of modernization cost recapture. Although there have been examples of digital technology usage in the nuclear power industry, challenges to the qualification of digital technology for high-integrity nuclear power plant (NPP) applications have severely constrained moremore » widespread progress in achieving the benefits that are possible through the transition to digital. The U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) established the Advanced Sensors and Instrumentation (ASI) technology area under the Nuclear Energy Enabling Technologies (NEET) Program to coordinate the instrumentation and controls (I&C) research across DOE NE and to identify and lead efforts to address common needs. As part of the NEET ASI research program, the Digital Technology Qualification project was established. Under this project, the Oak Ridge National Laboratory (ORNL) is leading the investigation into mitigation of digital common-cause failure (CCF) vulnerabilities for nuclear-qualified applications. This technical report documents updated and expanded findings from research activities by ORNL. Specifically, the report describes CCF experience in the nuclear and nonnuclear industries, identifies the state of the practice for CCF mitigation through key examples, and presents conclusions from the determination of knowledge gaps.« less

Silencing by nuclear matrix attachment distinguishes cell-type specificity: association with increased proliferation capacity

PubMed Central

Linnemann, Amelia K.; Krawetz, Stephen A.

2009-01-01

DNA loop organization by nuclear scaffold/matrix attachment is a key regulator of gene expression that may provide a means to modulate phenotype. We have previously shown that attachment of genes to the NaCl-isolated nuclear matrix correlates with their silencing in HeLa cells. In contrast, expressed genes were associated with the lithium 3,5-diiodosalicylate (LIS)-isolated nuclear scaffold. To define their role in determining phenotype matrix attached regions (MARs) on human chromosomes 14–18 were identified as a function of expression in a primary cell line. The locations of MARs in aortic adventitial fibroblast (AoAF) cells were very stable (r = 0.909) and 96% of genes attached at MARs are silent (P < 0.001). Approximately one-third of the genes uniquely expressed in AoAF cells were associated with the HeLa cell nuclear matrix and silenced. Comparatively, 81% were associated with the AoAF cell nuclear scaffold (P < 0.001) and expressed. This suggests that nuclear scaffold/matrix association mediates a portion of cell type-specific gene expression thereby modulating phenotype. Interestingly, nuclear matrix attachment and thus silencing of specific genes that regulate proliferation and maintain the integrity of the HeLa cell genome suggests that transformation may at least in part be achieved through aberrant nuclear matrix attachment. PMID:19276204

Performance Optimization of the Gasdynamic Mirror Propulsion System

NASA Technical Reports Server (NTRS)

Emrich, William J., Jr.; Kammash, Terry

1999-01-01

Nuclear fusion appears to be a most promising concept for producing extremely high specific impulse rocket engines. Engines such as these would effectively open up the solar system to human exploration and would virtually eliminate launch window restrictions. A preliminary vehicle sizing and mission study was performed based on the conceptual design of a Gasdynamic Mirror (GDM) fusion propulsion system. This study indicated that the potential specific impulse for this engine is approximately 142,000 sec. with about 22,100 N of thrust using a deuterium-tritium fuel cycle. The engine weight inclusive of the power conversion system was optimized around an allowable engine mass of 1500 Mg assuming advanced superconducting magnets and a Field Reversed Configuration (FRC) end plug at the mirrors. The vehicle habitat, lander, and structural weights are based on a NASA Mars mission study which assumes the use of nuclear thermal propulsion' Several manned missions to various planets were analyzed to determine fuel requirements and launch windows. For all fusion propulsion cases studied, the fuel weight remained a minor component of the total system weight regardless of when the missions commenced. In other words, the use of fusion propulsion virtually eliminates all mission window constraints and effectively allows unlimited manned exploration of the entire solar system. It also mitigates the need to have a large space infrastructure which would be required to support the transfer of massive amounts of fuel and supplies to lower a performing spacecraft.

Automated identification of the lung contours in positron emission tomography

NASA Astrophysics Data System (ADS)

Nery, F.; Silvestre Silva, J.; Ferreira, N. C.; Caramelo, F. J.; Faustino, R.

2013-03-01

Positron Emission Tomography (PET) is a nuclear medicine imaging technique that permits to analyze, in three dimensions, the physiological processes in vivo. One of the areas where PET has demonstrated its advantages is in the staging of lung cancer, where it offers better sensitivity and specificity than other techniques such as CT. On the other hand, accurate segmentation, an important procedure for Computer Aided Diagnostics (CAD) and automated image analysis, is a challenging task given the low spatial resolution and the high noise that are intrinsic characteristics of PET images. This work presents an algorithm for the segmentation of lungs in PET images, to be used in CAD and group analysis in a large patient database. The lung boundaries are automatically extracted from a PET volume through the application of a marker-driven watershed segmentation procedure which is robust to the noise. In order to test the effectiveness of the proposed method, we compared the segmentation results in several slices using our approach with the results obtained from manual delineation. The manual delineation was performed by nuclear medicine physicians that used a software routine that we developed specifically for this task. To quantify the similarity between the contours obtained from the two methods, we used figures of merit based on region and also on contour definitions. Results show that the performance of the algorithm was similar to the performance of human physicians. Additionally, we found that the algorithm-physician agreement is similar (statistically significant) to the inter-physician agreement.

Introduction and use of video-assisted endoscopic thyroidectomy for patients in Belarus affected by the Chernobyl nuclear disaster.

PubMed

Igarashi, Takehito; Shimizu, Kazuo; Yakubouski, Siarhei; Akasu, Haruki; Okamura, Ritsuko; Sugitani, Iwao; Jikuzono, Tomoo; Danilova, Larisa

2013-11-01

We developed video-assisted neck surgery (VANS) - a feasible, simple, and safe endoscopic thyroid procedure with cosmetic benefits - in 1998. To date, we have performed this procedure 633 times. We have also introduced the VANS method in Belarus, a country that was left contaminated by the Chernobyl nuclear disaster. From a mass screening, nine Belarusian patients, including two with papillary carcinoma of the thyroid, were selected to undergo an operation using the VANS method, performed by a single surgeon (author Shimizu). We compared indicating factors for minimally invasive surgery, specifically the operating time and blood loss, between the Belarusian cases and the 33 most recent cases performed at our institute in Tokyo. The procedures in Belarus were performed under very different working conditions than in Japan. However, operating time and blood loss improved for the Belarusian cases as the surgeon gained experience in this environment; all the cosmetic outcomes were excellent. Subsequently, over a 2-year period, surgeons in Belarus performed the VANS method, with modification, for 29 cases of thyroid tumor. The VANS method is easily learned by inexperienced surgeons without major technical problems. © 2013 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and Wiley Publishing Asia Pty Ltd.

Defect specific maintenance of SG tubes -- How safe is it?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cizelj, L.; Mavko, B.; Dvorsek, T.

1997-02-01

The efficiency of the defect specific plugging criterion for outside diameter stress corrosion cracking at tube support plates is assessed. The efficiency is defined by three parameters: (1) number of plugged tubes, (2) probability of steam generator tube rupture and (3) predicted accidental leak rate through the defects. A probabilistic model is proposed to quantify the probability of tube rupture, while procedures available in literature were used to define the accidental leak rates. The defect specific plugging criterion was then compared to the performance of traditional (45%) plugging criterion using realistic data from Krsko nuclear power plant. Advantages of themore » defect specific approach over the traditional one are clearly shown. Some hints on the optimization of safe life of steam generator are also given.« less

Qualitative and quantitative analysis of specific polysaccharides in Dendrobium huoshanense by using saccharide mapping and chromatographic methods.

PubMed

Deng, Yong; Chen, Ling-Xiao; Han, Bang-Xing; Wu, Ding-Tao; Cheong, Kit-Leong; Chen, Nai-Fu; Zhao, Jing; Li, Shao-Ping

2016-09-10

Qualitative and quantitative analysis of specific polysaccharides from ten batches of Dendrobium huoshanense were performed using high performance size exclusion chromatography coupled with multi-angle laser light scattering and refractive index detector (HPSEC-MALLS-RID), gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) and saccharide mapping based on polysaccharides analysis by using carbohydrate gel electrophoresis (PACE) and high performance thin layer chromatography (HPTLC). Results showed that molecular weights, the radius of gyrations, and contents of specific polysaccharides in D. huoshanense were ranging from 1.16×10(5) to 2.17×10(5)Da, 38.8 to 52.1nm, and 9.9% to 19.9%, respectively. Furthermore, the main monosaccharide compositions were Man and Glc. Indeed, the main glycosidic linkages were β-1,4-Manp and β-1,4-Glcp, and substituted with acetyl groups at O-2 and O-3 of 1,4-linked Manp. Moreover, results showed that PACE and HPTLC fingerprints of partial acidic and enzymatic hydrolysates of specific polysaccharides were similar, which are helpful to better understand the specific polysaccharides in D. huoshanense and beneficial to improve their quality control. These approaches could also be routinely used for quality control of polysaccharides in other medicinal plants. Copyright © 2016 Elsevier B.V. All rights reserved.

IBA studies of helium mobility in nuclear materials revisited

NASA Astrophysics Data System (ADS)

Trocellier, P.; Agarwal, S.; Miro, S.; Vaubaillon, S.; Leprêtre, F.; Serruys, Y.

2015-12-01

The aim of this paper is to point out and to discuss some features extracted from the study of helium migration in nuclear materials performed during the last fifteen years using ion beam analysis (IBA) measurements. The first part of this paper is devoted to a brief description of the two main IBA methods used, i.e. deuteron induced nuclear reaction for 3He depth profiling and high-energy heavy-ion induced elastic recoil detection analysis for 4He measurement. In the second part, we provide an overview of the different studies carried out on model nuclear waste matrices and model nuclear reactor structure materials in order to illustrate and discuss specific results in terms of key influence parameters in relation with thermal or radiation activated migration of helium. Finally, we show that among the key parameters we have investigated as able to influence the height of the helium migration barrier, the following can be considered as pertinent: the experimental conditions used to introduce helium (implanted ion energy and implantation fluence), the grain size of the matrix, the lattice cell volume, the Young's modulus, the ionicity degree of the chemical bond between the transition metal atom M and the non-metal atom X, and the width of the band gap.

Developing a taxonomy of coordination behaviours in nuclear power plant control rooms during emergencies.

PubMed

Wang, Dunxing; Gao, Qin; Li, Zhizhong; Song, Fei; Ma, Liang

2017-12-01

This study aims to develop a taxonomy of coordination behaviours during emergencies in nuclear power plants (NPPs). We summarised basic coordination behaviours from literature in aviation, health care and nuclear field and identified coordination behaviours specific to the nuclear domain by interviewing and surveying control crew operators. The established taxonomy includes 7 workflow stages and 24 basic coordination behaviours. To evaluate the reliability and feasibility of the taxonomy, we analysed 12 videos of operators' training sessions by coding coordination behaviours with the taxonomy and the inter-rater reliability was acceptable. Further analysis of the frequency, the duration and the direction of the coordination behaviours revealed four coordination problems. This taxonomy provides a foundation of systematic observation of coordination behaviours among NPP crews, advances researchers' understanding of the coordination mechanism during emergencies in NPPs and facilitate the possibility to deepen the understanding of the relationships between coordination behaviours and team performance. Practitioner Summary: A taxonomy of coordination behaviours during emergencies in nuclear power plants was developed. Reliability and feasibility of the taxonomy was verified through the analysis of 12 training sessions. The taxonomy can serve as an observation system for analysis of coordination behaviours and help to identify coordination problems of control crews.

Stress-induced interaction between p38 MAPK and HSP70

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Xiaowei, E-mail: gongxw@fimmu.com; Luo, Tingting; Deng, Peng

2012-08-24

Highlights: Black-Right-Pointing-Pointer HSP70 interacts to p38 MAPK in vitro and in vivo. Black-Right-Pointing-Pointer HSP70 co-localizes with p38 MAPK in the nucleus upon stress. Black-Right-Pointing-Pointer HSP70 is involved in the nuclear phosphorylation of MK2 by p38 MAPK. -- Abstract: p38 MAPK, one of the four MAPK subfamilies in mammalian cells, is activated by environmental stresses and pro-inflammatory cytokines, playing fundamental roles in many biological processes. Despite all that is known on the structure and functions of p38, many questions still exist. The coupling of activation and nuclear translocation represents an important aspect of p38 signaling. In our effort in exploring themore » potential chaperone for p38 translocation, we performed an endogenous pull-down assay and identified HSP70 as a potential interacting protein of p38. We confirmed the interaction between p38 and HSP70 in vitro and in vivo, and identified their interaction domains. We also showed stress-induced nuclear co-localization of these two proteins. Our preliminary result indicated that HSP70 was related to the phosphorylation of MK2, a specific nuclear downstream target of p38, suggesting HSP70 is a potential chaperone for the nuclear translocation of p38.« less

DNA-histone complexes as ligands amplify cell penetration and nuclear targeting of anti-DNA antibodies via energy-independent mechanisms.

PubMed

Zannikou, Markella; Bellou, Sofia; Eliades, Petros; Hatzioannou, Aikaterini; Mantzaris, Michael D; Carayanniotis, George; Avrameas, Stratis; Lymberi, Peggy

2016-01-01

We have generated three monoclonal cell-penetrating antibodies (CPAbs) from a non-immunized lupus-prone (NZB × NZW)F1 mouse that exhibited high anti-DNA serum titres. These CPAbs are polyreactive because they bind to DNA and other cellular components, and localize mainly in the nucleus of HeLa cells, albeit with a distinct nuclear labelling profile. Herein, we have examined whether DNA-histone complexes (DHC) binding to CPAbs, before cell entry, could modify the cell penetration of CPAbs or their nuclear staining properties. By applying confocal microscopy and image analysis, we found that extracellular binding of purified CPAbs to DHC significantly enhanced their subsequent cell-entry, both in terms of percentages of positively labelled cells and fluorescence intensity (internalized CPAb amount), whereas there was a variable effect on their nuclear staining profile. Internalization of CPAbs, either alone or bound to DHC, remained unaltered after the addition of endocytosis-specific inhibitors at 37° or assay performance at 4°, suggesting the involvement of energy-independent mechanisms in the internalization process. These findings assign to CPAbs a more complex pathogenetic role in systemic lupus erythematosus where both CPAbs and nuclear components are abundant. © 2015 John Wiley & Sons Ltd.

Cancer risks near nuclear facilities: the importance of research design and explicit study hypotheses.

PubMed

Wing, Steve; Richardson, David B; Hoffmann, Wolfgang

2011-04-01

In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design. We review epidemiologic principles used in studies of generic exposure-response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities. Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders. Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes.

Nuclear Enterprise Performance Measurement

DTIC Science & Technology

2011-03-01

xi I. Introduction ...WSA: Weapons Storage Area 1 I. Introduction Overview This paper discusses United States Air Force nuclear enterprise...sustainment systems. Keywords Performance measurement, process measurement, strategy, multicriteria decision- making, aggregation 1. Introduction Nuclear

Delivering safety

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, N.D.; Spooner, K.G.; Walkden, P.

2007-07-01

In the United Kingdom there have been significant recent changes to the management of civil nuclear liabilities. With the formation in April 2005 of the Nuclear Decommissioning Authority (NDA), ownership of the civil nuclear licensed sites in the UK, including the Magnox Reactor Stations, passed to this new organisation. The NDAs mission is to seek acceleration of the nuclear clean up programme and deliver increased value for money and, consequently, are driving their contractors to seek more innovative ways of performing work. British Nuclear Group manages the UK Magnox stations under contract to the NDA. This paper summarises the approachmore » being taken within its Reactor Sites business to work with suppliers to enhance working arrangements at sites, improve the delivery of decommissioning programmes and deliver improvements in safety and environmental performance. The UK Magnox stations are 1. generation gas-graphite reactors, constructed in the 1950's and 1960's. Two stations are currently still operating, three are shut-down undergoing defueling and the other five are being decommissioned. Despite the distractions of industry restructuring, an uncompromising policy of demanding improved performance in conjunction with improved safety and environmental standards has been adopted. Over the past 5 years, this policy has resulted in step-changes in performance at Reactor Sites, with increased electrical output and accelerated defueling and decommissioning. The improvements in performance have been mirrored by improvements in safety (DACR of 0 at 5 sites); environmental standards (reductions in energy and water consumption, increased waste recycling) and the overall health of the workforce (20% reduction in sickness absence). These achievements have, in turn, been recognised by external bodies, resulting in several awards, including: the world's first ISRS and IERS level 10 awards (Sizewell, 2006), the NUMEX plant maintenance award (Bradwell, 2006), numerous RoSPA awards at site and sector level and nomination, at Company level, for the RoSPA George Earle trophy for outstanding performance in Health and Safety (Reactor Sites, 2006). After 'setting the scene' and describing the challenges that the company has had to respond to, the paper explains how these improvements have been delivered. Specifically it explains the process that has been followed and the parts played by sites and suppliers to deliver improved performance. With the experience of already having transitioned several Magnox stations from operations to defueling and then to decommissioning, the paper describes the valuable experience that has been gained in achieving an optimum change process and maintaining momentum. (authors)« less

A muscle-specific knockout implicates nuclear receptor coactivator MED1 in the regulation of glucose and energy metabolism.

PubMed

Chen, Wei; Zhang, Xiaoting; Birsoy, Kivanc; Roeder, Robert G

2010-06-01

As conventional transcriptional factors that are activated in diverse signaling pathways, nuclear receptors play important roles in many physiological processes that include energy homeostasis. The MED1 subunit of the Mediator coactivator complex plays a broad role in nuclear receptor-mediated transcription by anchoring the Mediator complex to diverse promoter-bound nuclear receptors. Given the significant role of skeletal muscle, in part through the action of nuclear receptors, in glucose and fatty acid metabolism, we generated skeletal muscle-specific Med1 knockout mice. Importantly, these mice show enhanced insulin sensitivity and improved glucose tolerance as well as resistance to high-fat diet-induced obesity. Furthermore, the white muscle of these mice exhibits increased mitochondrial density and expression of genes specific to type I and type IIA fibers, indicating a fast-to-slow fiber switch, as well as markedly increased expression of the brown adipose tissue-specific UCP-1 and Cidea genes that are involved in respiratory uncoupling. These dramatic results implicate MED1 as a powerful suppressor in skeletal muscle of genetic programs implicated in energy expenditure and raise the significant possibility of therapeutical approaches for metabolic syndromes and muscle diseases through modulation of MED1-nuclear receptor interactions.

Assessment of MARMOT. A Mesoscale Fuel Performance Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonks, M. R.; Schwen, D.; Zhang, Y.

2015-04-01

MARMOT is the mesoscale fuel performance code under development as part of the US DOE Nuclear Energy Advanced Modeling and Simulation Program. In this report, we provide a high level summary of MARMOT, its capabilities, and its current state of validation. The purpose of MARMOT is to predict the coevolution of microstructure and material properties of nuclear fuel and cladding. It accomplished this using the phase field method coupled to solid mechanics and heat conduction. MARMOT is based on the Multiphysics Object-Oriented Simulation Environment (MOOSE), and much of its basic capability in the areas of the phase field method, mechanics,more » and heat conduction come directly from MOOSE modules. However, additional capability specific to fuel and cladding is available in MARMOT. While some validation of MARMOT has been completed in the areas of fission gas behavior and grain growth, much more validation needs to be conducted. However, new mesoscale data needs to be obtained in order to complete this validation.« less

Physical layer simulation study for the coexistence of WLAN standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howlader, M. K.; Keiger, C.; Ewing, P. D.

This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple accessmore » techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)« less

Brayton Power Conversion System Parametric Design Modelling for Nuclear Electric Propulsion

NASA Technical Reports Server (NTRS)

Ashe, Thomas L.; Otting, William D.

1993-01-01

The parametrically based closed Brayton cycle (CBC) computer design model was developed for inclusion into the NASA LeRC overall Nuclear Electric Propulsion (NEP) end-to-end systems model. The code is intended to provide greater depth to the NEP system modeling which is required to more accurately predict the impact of specific technology on system performance. The CBC model is parametrically based to allow for conducting detailed optimization studies and to provide for easy integration into an overall optimizer driver routine. The power conversion model includes the modeling of the turbines, alternators, compressors, ducting, and heat exchangers (hot-side heat exchanger and recuperator). The code predicts performance to significant detail. The system characteristics determined include estimates of mass, efficiency, and the characteristic dimensions of the major power conversion system components. These characteristics are parametrically modeled as a function of input parameters such as the aerodynamic configuration (axial or radial), turbine inlet temperature, cycle temperature ratio, power level, lifetime, materials, and redundancy.

Induction Heating Model of Cermet Fuel Element Environmental Test (CFEET)

NASA Technical Reports Server (NTRS)

Gomez, Carlos F.; Bradley, D. E.; Cavender, D. P.; Mireles, O. R.; Hickman, R. R.; Trent, D.; Stewart, E.

2013-01-01

Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames. Nuclear Thermal Rockets (NTR) are capable of producing a high specific impulse by employing heat produced by a fission reactor to heat and therefore accelerate hydrogen through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited. The primary concern is the mechanical failure of fuel elements due to large thermal gradients; therefore, high-melting-point ceramics-metallic matrix composites (cermets) are one of the fuels under consideration as part of the Nuclear Cryogenic Propulsion Stage (NCPS) Advance Exploration System (AES) technology project at the Marshall Space Flight Center. The purpose of testing and analytical modeling is to determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures and obtain data to assess the properties of the non-nuclear support materials. The fission process and the resulting heating performance are well known and do not require that active fissile material to be integrated in this testing. A small-scale test bed; Compact Fuel Element Environmental Tester (CFEET), designed to heat fuel element samples via induction heating and expose samples to hydrogen is being developed at MSFC to assist in optimal material and manufacturing process selection without utilizing fissile material. This paper details the analytical approach to help design and optimize the test bed using COMSOL Multiphysics for predicting thermal gradients induced by electromagnetic heating (Induction heating) and Thermal Desktop for radiation calculations.

EANM 2012 guidelines for radionuclide imaging of phaeochromocytoma and paraganglioma

PubMed Central

Timmers, Henri J.; Hindié, Elif; Guillet, Benjamin A.; Neumann, Hartmut P.; Walz, Martin K.; Opocher, Giuseppe; de Herder, Wouter W.; Boedeker, Carsten C.; de Krijger, Ronald R.; Chiti, Arturo; Al-Nahhas, Adil; Pacak, Karel

2016-01-01

Purpose Radionuclide imaging of phaeochromocytomas (PCCs) and paragangliomas (PGLs) involves various functional imaging techniques and approaches for accurate diagnosis, staging and tumour characterization. The purpose of the present guidelines is to assist nuclear medicine practitioners in performing, interpreting and reporting the results of the currently available SPECT and PET imaging approaches. These guidelines are intended to present information specifically adapted to European practice. Methods Guidelines from related fields, issued by the European Association of Nuclear Medicine and the Society of Nuclear Medicine, were taken into consideration and are partially integrated within this text. The same was applied to the relevant literature, and the final result was discussed with leading experts involved in the management of patients with PCC/PGL. The information provided should be viewed in the context of local conditions, laws and regulations. Conclusion Although several radionuclide imaging modalities are considered herein, considerable focus is given to PET imaging which offers high sensitivity targeted molecular imaging approaches. PMID:22926712

Aberrant Expression of Xist in Aborted Porcine Fetuses Derived from Somatic Cell Nuclear Transfer Embryos

PubMed Central

Yuan, Lin; Wang, Anfeng; Yao, Chaogang; Huang, Yongye; Duan, Feifei; Lv, Qinyan; Wang, Dongxu; Ouyang, Hongsheng; Li, Zhanjun; Lai, Liangxue

2014-01-01

Cloned pigs generated by somatic cell nuclear transfer (SCNT) show a greater ratio of early abortion during mid-gestation than normal controls. X-linked genes have been demonstrated to be important for the development of cloned embryos. To determine the relationship between the expression of X-linked genes and abortion of cloned porcine fetuses, the expression of X-linked genes were investigated by quantitative real-time polymerase chain reaction (q-PCR) and the methylation status of Xist DMR was performed by bisulfate-specific PCR (BSP). q-PCR analysis indicated that there was aberrant expression of X-linked genes, especially the upregulated expression of Xist in both female and male aborted fetuses compared to control fetuses. Results of BSP suggested that hypomethylation of Xist occurred in aborted fetuses, whether male or female. These results suggest that the abnormal expression of Xist may be associated with the abortion of fetuses derived from somatic cell nuclear transfer embryos. PMID:25429426

Damage tolerance of nuclear graphite at elevated temperatures

DOE PAGES

Liu, Dong; Gludovatz, Bernd; Barnard, Harold S.; ...

2017-06-30

Nuclear-grade graphite is a critically important high-temperature structural material for current and potentially next generation of fission reactors worldwide. It is imperative to understand its damage-tolerant behaviour and to discern the mechanisms of damage evolution under in-service conditions. Here we perform in situ mechanical testing with synchrotron X-ray computed micro-tomography at temperatures between ambient and 1,000 °C on a nuclear-grade Gilsocarbon graphite. We find that both the strength and fracture toughness of this graphite are improved at elevated temperature. Whereas this behaviour is consistent with observations of the closure of microcracks formed parallel to the covalent-sp 2-bonded graphene layers atmore » higher temperatures, which accommodate the more than tenfold larger thermal expansion perpendicular to these layers, we attribute the elevation in strength and toughness primarily to changes in the residual stress state at 800–1,000 °C, specifically to the reduction in significant levels of residual tensile stresses in the graphite that are ‘frozen-in’ following processing.« less

Damage tolerance of nuclear graphite at elevated temperatures

PubMed Central

Liu, Dong; Gludovatz, Bernd; Barnard, Harold S.; Kuball, Martin; Ritchie, Robert O.

2017-01-01

Nuclear-grade graphite is a critically important high-temperature structural material for current and potentially next generation of fission reactors worldwide. It is imperative to understand its damage-tolerant behaviour and to discern the mechanisms of damage evolution under in-service conditions. Here we perform in situ mechanical testing with synchrotron X-ray computed micro-tomography at temperatures between ambient and 1,000 °C on a nuclear-grade Gilsocarbon graphite. We find that both the strength and fracture toughness of this graphite are improved at elevated temperature. Whereas this behaviour is consistent with observations of the closure of microcracks formed parallel to the covalent-sp2-bonded graphene layers at higher temperatures, which accommodate the more than tenfold larger thermal expansion perpendicular to these layers, we attribute the elevation in strength and toughness primarily to changes in the residual stress state at 800–1,000 °C, specifically to the reduction in significant levels of residual tensile stresses in the graphite that are ‘frozen-in’ following processing. PMID:28665405

Analytical design and performance studies of nuclear furnace tests of small nuclear light bulb models

NASA Technical Reports Server (NTRS)

Latham, T. S.; Rodgers, R. J.

1972-01-01

Analytical studies were continued to identify the design and performance characteristics of a small-scale model of a nuclear light bulb unit cell suitable for testing in a nuclear furnace reactor. Emphasis was placed on calculating performance characteristics based on detailed radiant heat transfer analyses, on designing the test assembly for ease of insertion, connection, and withdrawal at the reactor test cell, and on determining instrumentation and test effluent handling requirements. In addition, a review of candidate test reactors for future nuclear light bulb in-reactor tests was conducted.

Non-Nuclear Testing of Fission Technologies at NASA MSFC

NASA Technical Reports Server (NTRS)

Houts, Robert G.; Pearson, J. Boise; Aschenbrenner, Kenneth C.; Bradley, David E.; Dickens, Ricky E.; Emrich, William J.; Garber, Anne E.; Godfroy, Thomas J.; Harper, Roger T.; Martin, Jim J.;

NTREES Testing and Operations Status

NASA Technical Reports Server (NTRS)

Emrich, Bill

2007-01-01

Nuclear Thermal Rockets or NTR's have been suggested as a propulsion system option for vehicles traveling to the moon or Mars. These engines are capable of providing high thrust at specific impulses at least twice that of today's best chemical engines. The performance constraints on these engines are mainly the result of temperature limitations on the fuel coupled with a limited ability to withstand chemical attack by the hot hydrogen propellant. To operate at maximum efficiency, fuel forms are desired which can withstand the extremely hot, hostile environment characteristic of NTR operation for at least several hours. The simulation of such an environment would require an experimental device which could simultaneously approximate the power, flow, and temperature conditions which a nuclear fuel element (or partial element) would encounter during NTR operation. Such a simulation would allow detailed studies of the fuel behavior and hydrogen flow characteristics under reactor like conditions to be performed. Currently, the construction of such a simulator has been completed at the Marshall Space Flight Center, and will be used in the future to evaluate a wide variety of fuel element designs and the materials of which they are fabricated. This present work addresses the operational status of the Nuclear Thermal Rocket Element Environmental Simulator or NTREES and some of the design considerations which were considered prior to and during its construction.

Dual-mode imaging with radiolabeled gold nanorods

NASA Astrophysics Data System (ADS)

Agarwal, Ashish; Shao, Xia; Rajian, Justin R.; Zhang, Huanan; Chamberland, David L.; Kotov, Nicholas A.; Wang, Xueding

2011-05-01

Many nanoparticle contrast agents have difficulties with deep tissue and near-bone imaging due to limited penetration of visible photons in the body and mineralized tissues. We are looking into the possibility of mediating this problem while retaining the capabilities of the high spatial resolution associated with optical imaging. As such, the potential combination of emerging photoacoustic imaging and nuclear imaging in monitoring of antirheumatic drug delivery by using a newly developed dual-modality contrast agent is investigated. The contrast agent is composed of gold nanorods (GNRs) conjugated to the tumor necrosis factor (TNF-α) antibody and is subsequently radiolabeled by 125I. ELISA experiments designed to test TNF-α binding are performed to prove the specificity and biological activity of the radiolabeled conjugated contrast agent. Photoacoustic and nuclear imaging are performed to visualize the distribution of GNRs in articular tissues of the rat tail joints in situ. Findings from the two imaging modalities correspond well with each other in all experiments. Our system can image GNRs down to a concentration of 10 pM in biological tissues and with a radioactive label of 5 μCi. This study demonstrates the potential of combining photoacoustic and nuclear imaging modalities through one targeted contrast agent for noninvasive monitoring of drug delivery as well as deep and mineralized tissue imaging.

Testing piezoelectric sensors in a nuclear reactor environment

NASA Astrophysics Data System (ADS)

Reinhardt, Brian T.; Suprock, Andy; Tittmann, Bernhard

2017-02-01

Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE's FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this work piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts Institute of Technology Research reactor to a fast neutron fluence of 8.65×1020 nf/cm2. It is demonstrated that Bismuth Titanate is capable of transduction up to 5 × 1020 nf/cm2, Zinc Oxide is capable of transduction up to at least 6.27 × 1020 nf/cm2, and Aluminum Nitride is capable of transduction up to at least 8.65 × 1020 nf/cm2.

Application of Recommended Design Practices for Conceptual Nuclear Fusion Space Propulsion Systems

NASA Technical Reports Server (NTRS)

Williams, Craig H.

2004-01-01

An AIAA Special Project Report was recently produced by AIAA's Nuclear and Future Flight Propulsion Technical Committee and is currently in peer review. The Report provides recommended design practices for conceptual engineering studies of nuclear fusion space propulsion systems. Discussion and recommendations are made on key topics including design reference missions, degree of technological extrapolation and concomitant risk, thoroughness in calculating mass properties (nominal mass properties, weight-growth contingency and propellant margins, and specific impulse), and thoroughness in calculating power generation and usage (power-flow, power contingencies, specific power). The report represents a general consensus of the nuclear fusion space propulsion system conceptual design community and proposes 15 recommendations. This paper expands on the Report by providing specific examples illustrating how to apply each of the recommendations.

Reliability and mass analysis of dynamic power conversion systems with parallel of standby redundancy

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Bloomfield, H. S.

1985-01-01

A combinatorial reliability approach is used to identify potential dynamic power conversion systems for space mission applications. A reliability and mass analysis is also performed, specifically for a 100 kWe nuclear Brayton power conversion system with parallel redundancy. Although this study is done for a reactor outlet temperature of 1100K, preliminary system mass estimates are also included for reactor outlet temperatures ranging up to 1500 K.

Nuclear Architecture of Mouse Spermatocytes: Chromosome Topology, Heterochromatin, and Nucleolus.

PubMed

Berrios, Soledad

2017-01-01

The nuclear organization of spermatocytes in meiotic prophase I is primarily determined by the synaptic organization of the bivalents that are bound by their telomeres to the nuclear envelope and described as arc-shaped trajectories through the 3D nuclear space. However, over this basic meiotic organization, a spermatocyte nuclear architecture arises that is based on higher-ordered patterns of spatial associations among chromosomal domains from different bivalents that are conditioned by the individual characteristics of chromosomes and the opportunity for interactions between their domains. Consequently, the nuclear architecture is species-specific and prone to modification by chromosomal rearrangements. This model is valid for the localization of any chromosomal domain in the meiotic prophase nucleus. However, constitutive heterochromatin plays a leading role in shaping nuclear territories. Thus, the nuclear localization of nucleoli depends on the position of NORs in nucleolar bivalents, but the association among nucleolar chromosomes mainly depends on the presence of constitutive heterochromatin that does not affect the expression of the ribosomal genes. Constitutive heterochromatin and nucleoli form complex nuclear territories whose distribution in the nuclear space is nonrandom, supporting the hypothesis regarding the existence of a species-specific nuclear architecture in first meiotic prophase spermatocytes. © 2017 S. Karger AG, Basel.

To discuss illicit nuclear trafficking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balatsky, Galya I; Severe, William R; Wallace, Richard K

2010-01-01

The Illicit nuclear trafficking panel was conducted at the 4th Annual INMM workshop on Reducing the Risk from Radioactive and Nuclear Materials on February 2-3, 2010 in Washington DC. While the workshop occurred prior to the Nuclear Security Summit, April 12-13 2010 in Washington DC, some of the summit issues were raised during the workshop. The Communique of the Washington Nuclear Security Summit stated that 'Nuclear terrorism is one of the most challenging threats to international security, and strong nuclear security measures are the most effective means to prevent terrorists, criminals, or other unauthorized actors from acquiring nuclear materials.' Themore » Illicit Trafficking panel is one means to strengthen nuclear security and cooperation at bilateral, regional and multilateral levels. Such a panel promotes nuclear security culture through technology development, human resources development, education and training. It is a tool which stresses the importance of international cooperation and coordination of assistance to improve efforts to prevent and respond to incidents of illicit nuclear trafficking. Illicit trafficking panel included representatives from US government, an international organization (IAEA), private industry and a non-governmental organization to discuss illicit nuclear trafficking issues. The focus of discussions was on best practices and challenges for addressing illicit nuclear trafficking. Terrorism connection. Workshop discussions pointed out the identification of terrorist connections with several trafficking incidents. Several trafficking cases involved real buyers (as opposed to undercover law enforcement agents) and there have been reports identifying individuals associated with terrorist organizations as prospective plutonium buyers. Some specific groups have been identified that consistently search for materials to buy on the black market, but no criminal groups were identified that specialize in nuclear materials or isotope smuggling. In most cases, sellers do not find legitimate buyers; however, there have been specific cases where sellers did find actual terrorist group representatives. There appears to be a connection between terrorist groups engaged in trafficking conventional arms and explosives components that are also looking for both nuclear materials and radioisotopes. Sale opportunities may create additional demand for such materials. As we can observe from Figure 1, many cases in the mid-90s involved kilogram quantities of material. There were smaller amounts of material moved in 2001, 2003 and 2006. While we have seen less trafficking cases involving PujHEU in recent years, the fact that it continues at all is troubling. The trafficking cases can be presented through their life cycle: Diversion of materials leads to Trafficker and then to Terrorist/Proliferator. Most of the information we have in trafficking cases is on the Trafficker. In 16 cases reported by the IAEA, there are 10 prosecutions of the involved trafficker. However, there are no confirmed diversions of material recorded in any of the 18 seizures. Most seizures were sting operations performed by law enforcement or security agents with no actual illicit end-user involved.« less

21 CFR 866.5820 - Systemic lupus erythema-tosus immunological test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... with cellular nuclear double-stranded deoxyribonucleic acid (DNA) or other nuclear constituents that are specifically diagnostic of SLE. Measurement of nuclear double-stranded DNA antibodies aids in the...

21 CFR 866.5820 - Systemic lupus erythema-tosus immunological test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... with cellular nuclear double-stranded deoxyribonucleic acid (DNA) or other nuclear constituents that are specifically diagnostic of SLE. Measurement of nuclear double-stranded DNA antibodies aids in the...

21 CFR 866.5820 - Systemic lupus erythema-tosus immunological test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... with cellular nuclear double-stranded deoxyribonucleic acid (DNA) or other nuclear constituents that are specifically diagnostic of SLE. Measurement of nuclear double-stranded DNA antibodies aids in the...

21 CFR 866.5820 - Systemic lupus erythema-tosus immunological test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... with cellular nuclear double-stranded deoxyribonucleic acid (DNA) or other nuclear constituents that are specifically diagnostic of SLE. Measurement of nuclear double-stranded DNA antibodies aids in the...

Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

PubMed

Bakshi, Jayeesh

2018-04-01

Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

Prostate-specific membrane antigen-based imaging in prostate cancer: impact on clinical decision making process.

PubMed

Demirkol, Mehmet Onur; Acar, Ömer; Uçar, Burcu; Ramazanoğlu, Sultan Rana; Sağlıcan, Yeşim; Esen, Tarık

2015-05-01

There is an ongoing need for an accurate imaging modality which can be used for staging purposes, metastatic evaluation, predicting biologic aggresiveness and investigating recurrent disease in prostate cancer. Prostate specific membrane antigen, given its favorable molecular characteristics, holds a promise as an ideal target for prostate cancer-specific nuclear imaging. In this study, we evaluated our initial results of PSMA based PET/CT imaging in prostate cancer. A total of 22 patients with a median age and serum PSA level of 68 years and 4.15 ng/ml, respectively underwent Ga-68 PSMA PET/CT in our hospital between Februrary and August 2014. Their charts were retrospectively reviewed in order to document the clinical characteristics, the indications for and the results of PSMA based imaging and the impact of Ga-68 PSMA PET/CT findings on disease management. The most common indications were rising PSA after local ± adjuvant treatment followed by staging and metastatic evaluation before definitive or salvage treatment. All except 2 patients had prostatic ± extraprostatic PSMA positive lesions. For those who had a positive result; treatment strategies were tailored accordingly. Above the PSA level of 2 ng/ml, none of the PSMA based nuclear imaging studies revealed negative results. PSMA based nuclear imaging has significantly impacted our way of handling patients with prostate cancer. Its preliminary performance in different clinical scenarios and ability to detect lesions even in low PSA values seems fairly promising and deserves to be supplemented with further clinical studies. © 2015 Wiley Periodicals, Inc.

Going nuclear: The spread of nuclear weapons 1986-1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spector, L.S.

1987-01-01

In the third annual report of the Carnegie Endowment for International Peace on the spread of nuclear weapons, Spector provides a critical survey of the status of nuclear proliferation throughout the world and examines the nuclear potential of nations in the Middle East, Asia, Africa, and Latin America. Drawing on both historical documents and up-to-date reports, the author addresses such specific topics as Israel's nuclear arsenal, nuclear terrorism and its global security implications, arms control and nuclear safeguards, international treaties, weapons buildup, and political radicalism and unrest in nuclear-threshold nations.

Adenylyl cyclase A expression is tip-specific in Dictyostelium slugs and directs StatA nuclear translocation and CudA gene expression.

PubMed

Verkerke-van Wijk, I; Fukuzawa, M; Devreotes, P N; Schaap, P

2001-06-01

cAMP oscillations, generated by adenylyl cyclase A (ACA), coordinate cell aggregation in Dictyostelium and have also been implicated in organizer function during multicellular development. We used a gene fusion of the ACA promoter with a labile lacZ derivative to study the expression pattern of ACA. During aggregation, most cells expressed ACA, but thereafter expression was lost in all cells except those of the anterior tip. Before aggregation, ACA transcription was strongly upregulated by nanomolar cAMP pulses. Postaggregative transcription was sustained by nanomolar cAMP pulses, but downregulated by a continuous micromolar cAMP stimulus and by the stalk-cell-inducing factor DIF. Earlier work showed that the transcription factor StatA displays tip-specific nuclear translocation and directs tip-specific expression of the nuclear protein CudA, which is essential for culmination. Both StatA and CudA were present in nuclei throughout the entire slug in an aca null mutant that expresses ACA from the constitutive actin15 promoter. This suggests that the tip-specific expression of ACA directs tip-specific nuclear translocation of StatA and tip-specific expression of CudA. Copyright 2001 Academic Press.

Realistic Development and Testing of Fission System at a Non-Nuclear Testing Facility

NASA Technical Reports Server (NTRS)

Godfroy, Tom; VanDyke, Melissa; Dickens, Ricky; Pedersen, Kevin; Lenard, Roger; Houts, Mike

2000-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on a module has been performed at the Marshall Space Flight Center in the Propellant Energy Source Testbed (PEST). This paper discusses the experimental facilities and equipment used for performing resistance heated tests. Recommendations are made for improving non-nuclear test facilities and equipment for simulated testing of nuclear systems.

Realistic development and testing of fission systems at a non-nuclear testing facility

NASA Astrophysics Data System (ADS)

Godfroy, Tom; van Dyke, Melissa; Dickens, Ricky; Pedersen, Kevin; Lenard, Roger; Houts, Mike

2000-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on a module has been performed at the Marshall Space Flight Center in the Propellant Energy Source Testbed (PEST). This paper discusses the experimental facilities and equipment used for performing resistance heated tests. Recommendations are made for improving non-nuclear test facilities and equipment for simulated testing of nuclear systems. .

AGC 2 Irradiated Material Properties Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohrbaugh, David Thomas

2017-05-01

The Advanced Reactor Technologies Graphite Research and Development Program is conducting an extensive graphite irradiation experiment to provide data for licensing of a high temperature reactor (HTR) design. In past applications, graphite has been used effectively as a structural and moderator material in both research and commercial high temperature gas cooled reactor designs. , Nuclear graphite H 451, used previously in the United States for nuclear reactor graphite components, is no longer available. New nuclear graphite grades have been developed and are considered suitable candidates for new HTR reactor designs. To support the design and licensing of HTR core componentsmore » within a commercial reactor, a complete properties database must be developed for these current grades of graphite. Quantitative data on in service material performance are required for the physical, mechanical, and thermal properties of each graphite grade, with a specific emphasis on data accounting for the life limiting effects of irradiation creep on key physical properties of the HTR candidate graphite grades. Further details on the research and development activities and associated rationale required to qualify nuclear grade graphite for use within the HTR are documented in the graphite technology research and development plan.« less

AGC 2 Irradiation Creep Strain Data Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Windes, William E.; Rohrbaugh, David T.; Swank, W. David

2016-08-01

The Advanced Reactor Technologies Graphite Research and Development Program is conducting an extensive graphite irradiation experiment to provide data for licensing of a high temperature reactor (HTR) design. In past applications, graphite has been used effectively as a structural and moderator material in both research and commercial high temperature gas cooled reactor designs. Nuclear graphite H-451, used previously in the United States for nuclear reactor graphite components, is no longer available. New nuclear graphite grades have been developed and are considered suitable candidates for new HTR reactor designs. To support the design and licensing of HTR core components within amore » commercial reactor, a complete properties database must be developed for these current grades of graphite. Quantitative data on in service material performance are required for the physical, mechanical, and thermal properties of each graphite grade, with a specific emphasis on data accounting for the life limiting effects of irradiation creep on key physical properties of the HTR candidate graphite grades. Further details on the research and development activities and associated rationale required to qualify nuclear grade graphite for use within the HTR are documented in the graphite technology research and development plan.« less

Computerized engineering logic for nuclear procurement and dedication processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tulay, M.P.

1996-12-31

In an attempt to better meet the needs of operations and maintenance organizations, many nuclear utility procurement engineering groups have simplified their procedures, developed on-line tools for performing the specification of replacement items, and developed relational databases containing part-level information necessary to automate the procurement process. Although these improvements have helped to reduce the engineering necessary to properly specify and accept/dedicate items for nuclear safety-related applications, a number of utilities have recognized that additional long-term savings can be realized by integrating a computerized logic to assist technical procurement engineering personnel. The most commonly used logic follows the generic processes containedmore » in Electric Power Research Institute (EPRI) published guidelines. The processes are typically customized to some extent to accommodate each utility`s organizational structure, operating procedures, and strategic goals. This paper will discuss a typical logic that integrates the technical evaluation, acceptance, and receipt inspection and testing processes. The logic this paper will describe has been successfully integrated at a growing number of nuclear utilities and has produced numerous positive results. The application of the logic ensures that utility-wide standards or procedures, common among multi-site utilities, are followed.« less

The Paucity Problem: Where Have All the Space Reactor Experiments Gone?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bess, John D.; Marshall, Margaret A.

2016-10-01

The Handbooks of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) together contain a plethora of documented and evaluated experiments essential in the validation of nuclear data, neutronics codes, and modeling of various nuclear systems. Unfortunately, only a minute selection of handbook data (twelve evaluations) are of actual experimental facilities and mockups designed specifically for space nuclear research. There is a paucity problem, such that the multitude of space nuclear experimental activities performed in the past several decades have yet to be recovered and made available in such detail that themore » international community could benefit from these valuable historical research efforts. Those experiments represent extensive investments in infrastructure, expertise, and cost, as well as constitute significantly valuable resources of data supporting past, present, and future research activities. The ICSBEP and IRPhEP were established to identify and verify comprehensive sets of benchmark data; evaluate the data, including quantification of biases and uncertainties; compile the data and calculations in a standardized format; and formally document the effort into a single source of verified benchmark data. See full abstract in attached document.« less

A Strategy for Skills to meet the demands of Nuclear Decommissioning and Clean-up in the UK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brownridge, M.; Ensor, B.

The NDA remit as set out within the Energy Act includes - 'to ensure the availability of skills required to deliver the overall decommissioning and nuclear clean-up mission'. The NDA approach to meeting their statutory obligation is by: - finding the best ways of re-training, re-skilling or re-deploying people in a way that encourages a more flexible workforce; - identifying and communicating the skills and workforce requirements to deliver the mission; and - developing the infrastructure and capability initiatives in line with long term needs, for example, a National Skills Academy for Nuclear, Nuclear Institute, National Graduate Scheme, and -more » developing locally specific provision. Firstly, NDA has set the requirement for nuclear sites to write down within the Life Time Plans (LTP), at a high level, their Site Skills Strategies; furthermore, a National Skills Working Group has been established to develop tactical cross sector solutions to support the NDA's Skills Strategy. In support of the short, medium and long term needs to meet demands of the NDA sites and the nuclear decommissioning sector, as well as being aware of the broader nuclear sector, investments have been made in infrastructure and skills programmes such as: - A National Skills Academy for Nuclear - including UK wide representation of the whole nuclear sector; - A Nuclear Institute in partnership with the University of Manchester focussing on world class research and skills in Radiation Sciences and Decommissioning Engineering; - Post Graduate sponsorship for decommissioning related projects; - A National Graduate Scheme partnership with nuclear related employers; - Vocational qualifications and Apprenticeship Schemes - Engaging 14-19 year old students to encourage the take up of Science related subjects; and - A sector wide 'Skills Passport'. In conclusion: The skills challenge has many dimensions but requires addressing due to the clear link to improved business performance and the availability of key resources in a diminishing and competitive environment. The diminishing skill base is due to reasons such as demographics and competition from other industries such as the oil industry. Getting the balance between meeting regional and national requirements will prove critical to success. The lack of clarity on the long term needs will also drive the strategy. NDA recognises that the work to date is the beginning of a long term approach and programme. We have developed a skills strategy that is consistent across all 20 sites and examples of key developments in infrastructure are in progress. Looking forward NDA will seek benchmarking opportunities and ways to make tangible links between skills and performance. (authors)« less

Drosophila TIM binds importin α1, and acts as an adapter to transport PER to the nucleus.

PubMed

Jang, A Reum; Moravcevic, Katarina; Saez, Lino; Young, Michael W; Sehgal, Amita

2015-02-01

Regulated nuclear entry of clock proteins is a conserved feature of eukaryotic circadian clocks and serves to separate the phase of mRNA activation from mRNA repression in the molecular feedback loop. In Drosophila, nuclear entry of the clock proteins, PERIOD (PER) and TIMELESS (TIM), is tightly controlled, and impairments of this process produce profound behavioral phenotypes. We report here that nuclear entry of PER-TIM in clock cells, and consequently behavioral rhythms, require a specific member of a classic nuclear import pathway, Importin α1 (IMPα1). In addition to IMPα1, rhythmic behavior and nuclear expression of PER-TIM require a specific nuclear pore protein, Nup153, and Ran-GTPase. IMPα1 can also drive rapid and efficient nuclear expression of TIM and PER in cultured cells, although the effect on PER is mediated by TIM. Mapping of interaction domains between IMPα1 and TIM/PER suggests that TIM is the primary cargo for the importin machinery. This is supported by attenuated interaction of IMPα1 with TIM carrying a mutation previously shown to prevent nuclear entry of TIM and PER. TIM is detected at the nuclear envelope, and computational modeling suggests that it contains HEAT-ARM repeats typically found in karyopherins, consistent with its role as a co-transporter for PER. These findings suggest that although PER is the major timekeeper of the clock, TIM is the primary target of nuclear import mechanisms. Thus, the circadian clock uses specific components of the importin pathway with a novel twist in that TIM serves a karyopherin-like role for PER.

The role of women in nuclear - attracting public participation in regulatory decision-making process

NASA Astrophysics Data System (ADS)

Mohamad Jais, Azlina; Hassan, Najwa

2018-01-01

Public participation is vital in demonstrating transparency and enhancing effectiveness of a nuclear regulatory process. As such, it is necessary for nuclear practitioners to involve the public in key nuclear delivery milestones. This paper specifically discusses challenges faced in attracting public participation throughout the nuclear regulatory decision-making process, and highlights the roles of women in nuclear (WiN) in initiating the said public discourse.

First in-core simultaneous measurements of nuclear heating and thermal neutron flux obtained with the innovative mobile calorimeter CALMOS inside the OSIRIS reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepeltier, Valerie; Bubendorff, Jacques; Carcreff, Hubert

2015-07-01

Nuclear heating inside a MTR reactor has to be known in order to design and to run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. The innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70 MWth OSIRIS reactor operated by CEA. Thanks to a new type of calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. This development required preliminary modelling and irradiation of mock-ups of the calorimetric probe in the ex-core area, where nuclear heatingmore » rate does not exceed 2 W.g{sup -1}. The calorimeter working modes, the different measurement procedures allowed with such a new probe, the main modeling and experimental results and expected advantages of this new technique have been already presented. However, these first in-core measurements were not performed beyond 6 W.g{sup -1}, due to an inside temperature limitation imposed by a safety authority requirement. In this paper, we present the first in-core simultaneous measurements of nuclear heating and conventional thermal neutron flux obtained by the CALMOS device at the 70 MW nominal reactor power. For the first time, this experimental system was operated in nominal in-core conditions, with nominal neutron flux up to 2.7 10{sup 14} n.cm{sup -2}.s{sup -1} and nuclear heating up to 12 W.g{sup -1}. A comprehensive measurement campaign carried out from 2013 to 2015 inside all accessible irradiation locations of the core, allowed to qualify definitively this new device, not only in terms of measurement ability but also in terms of reliability. After a brief reminder of the calorimetric cell configuration and displacement system specificities, first nuclear heating distributions at nominal power are presented and discussed. In order to reinforce the heating evaluation, a systematic comparison is made between results obtained by different methods, the probe calibration coefficient and the zero method. Thermal neutron flux evaluation from the SPND signal processing required a specific TRIPOLI-4 Monte Carlo calculation which has been performed with the precise CALMOS cell geometry. In addition, the Finite Element model for temperatures map prediction inside the calorimetric cell has been upgraded with the recent experimental data obtained up to 12 W.g{sup -1}. The Kc coefficient, taking into account nonlinearities with regard to the calibration, has been reevaluated so as to make relevant measurements up to the nominal reactor power. Finally, the experience feedback acquired until now with this first CALMOS version led us to improvement perspectives. A second device is currently under manufacturing and main technical options chosen for this second version are presented. (authors)« less

Nuclear Cryogenic Propulsion Stage (NCPS) Fuel Element Testing in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

NASA Technical Reports Server (NTRS)

Emrich, William J., Jr.

2017-01-01

To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). Last year NTREES was successfully used to satisfy a testing milestone for the Nuclear Cryogenic Propulsion Stage (NCPS) project and met or exceeded all required objectives.

Fission yeast Lem2 and Man1 perform fundamental functions of the animal cell nuclear lamina.

PubMed

Gonzalez, Yanira; Saito, Akira; Sazer, Shelley

2012-01-01

In animal cells the nuclear lamina, which consists of lamins and lamin-associated proteins, serves several functions: it provides a structural scaffold for the nuclear envelope and tethers proteins and heterochromatin to the nuclear periphery. In yeast, proteins and large heterochromatic domains including telomeres are also peripherally localized, but there is no evidence that yeast have lamins or a fibrous nuclear envelope scaffold. Nonetheless, we found that the Lem2 and Man1 proteins of the fission yeast Schizosaccharomyces pombe, evolutionarily distant relatives of the Lap2/Emerin/Man1 (LEM) sub-family of animal cell lamin-associated proteins, perform fundamental functions of the animal cell lamina. These integral inner nuclear membrane localized proteins, with nuclear localized DNA binding Helix-Extension-Helix (HEH) domains, impact nuclear envelope structure and integrity, are essential for the enrichment of telomeres at the nuclear periphery and by means of their HEH domains anchor chromatin, most likely transcriptionally repressed heterochromatin, to the nuclear periphery. These data indicate that the core functions of the nuclear lamina are conserved between fungi and animal cells and can be performed in fission yeast, without lamins or other intermediate filament proteins.

Mechanism for G2 phase-specific nuclear export of the kinetochore protein CENP-F.

PubMed

Loftus, Kyle M; Cui, Heying; Coutavas, Elias; King, David S; Ceravolo, Amanda; Pereiras, Dylan; Solmaz, Sozanne R

2017-08-03

Centromere protein F (CENP-F) is a component of the kinetochore and a regulator of cell cycle progression. CENP-F recruits the dynein transport machinery and orchestrates several cell cycle-specific transport events, including transport of the nucleus, mitochondria and chromosomes. A key regulatory step for several of these functions is likely the G2 phase-specific export of CENP-F from the nucleus to the cytosol, where the cytoplasmic dynein transport machinery resides; however, the molecular mechanism of this process is elusive. Here, we have identified 3 phosphorylation sites within the bipartite classical nuclear localization signal (cNLS) of CENP-F. These sites are specific for cyclin-dependent kinase 1 (Cdk1), which is active in G2 phase. Phosphomimetic mutations of these residues strongly diminish the interaction of the CENP-F cNLS with its nuclear transport receptor karyopherin α. These mutations also diminish nuclear localization of the CENP-F cNLS in cells. Notably, the cNLS is phosphorylated in the -1 position, which is important to orient the adjacent major motif for binding into its pocket on karyopherin α. We propose that localization of CENP-F is regulated by a cNLS, and a nuclear export pathway, resulting in nuclear localization during most of interphase. In G2 phase, the cNLS is weakened by phosphorylation through Cdk1, likely resulting in nuclear export of CENP-F via the still active nuclear export pathway. Once CENP-F resides in the cytosol, it can engage in pathways that are important for cell cycle progression, kinetochore assembly and the faithful segregation of chromosomes into daughter cells.

10 CFR 35.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... nuclear pharmacist means a pharmacist who— (1) Meets the requirements in §§ 35.55(a) and 35.59; or (2) Is identified as an authorized nuclear pharmacist on— (i) A specific license issued by the Commission or...; or (3) Is identified as an authorized nuclear pharmacist by a commercial nuclear pharmacy that has...

10 CFR 35.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... nuclear pharmacist means a pharmacist who— (1) Meets the requirements in §§ 35.55(a) and 35.59; or (2) Is identified as an authorized nuclear pharmacist on— (i) A specific license issued by the Commission or...; or (3) Is identified as an authorized nuclear pharmacist by a commercial nuclear pharmacy that has...

10 CFR 35.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... nuclear pharmacist means a pharmacist who— (1) Meets the requirements in §§ 35.55(a) and 35.59; or (2) Is identified as an authorized nuclear pharmacist on— (i) A specific license issued by the Commission or...; or (3) Is identified as an authorized nuclear pharmacist by a commercial nuclear pharmacy that has...

10 CFR 35.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... nuclear pharmacist means a pharmacist who— (1) Meets the requirements in §§ 35.55(a) and 35.59; or (2) Is identified as an authorized nuclear pharmacist on— (i) A specific license issued by the Commission or...; or (3) Is identified as an authorized nuclear pharmacist by a commercial nuclear pharmacy that has...

10 CFR 35.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... nuclear pharmacist means a pharmacist who— (1) Meets the requirements in §§ 35.55(a) and 35.59; or (2) Is identified as an authorized nuclear pharmacist on— (i) A specific license issued by the Commission or...; or (3) Is identified as an authorized nuclear pharmacist by a commercial nuclear pharmacy that has...

26 CFR 1.88-1 - Nuclear decommissioning costs.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Nuclear decommissioning costs. 1.88-1 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.88-1 Nuclear decommissioning costs. (a) In general. Section 88 provides that the amount of nuclear decommissioning costs...

26 CFR 1.88-1 - Nuclear decommissioning costs.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Nuclear decommissioning costs. 1.88-1 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.88-1 Nuclear decommissioning costs. (a) In general. Section 88 provides that the amount of nuclear decommissioning costs...

10 CFR 150.21 - Transportation of special nuclear material by aircraft.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Transportation of special nuclear material by aircraft. 150.21 Section 150.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED... Transportation of special nuclear material by aircraft. Except as specifically approved by the Commission no...

26 CFR 1.88-1 - Nuclear decommissioning costs.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Nuclear decommissioning costs. 1.88-1 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.88-1 Nuclear decommissioning costs. (a) In general. Section 88 provides that the amount of nuclear decommissioning costs...

10 CFR 150.21 - Transportation of special nuclear material by aircraft.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Transportation of special nuclear material by aircraft. 150.21 Section 150.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED... Transportation of special nuclear material by aircraft. Except as specifically approved by the Commission no...

10 CFR 150.21 - Transportation of special nuclear material by aircraft.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Transportation of special nuclear material by aircraft. 150.21 Section 150.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED... Transportation of special nuclear material by aircraft. Except as specifically approved by the Commission no...

26 CFR 1.88-1 - Nuclear decommissioning costs.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Nuclear decommissioning costs. 1.88-1 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.88-1 Nuclear decommissioning costs. (a) In general. Section 88 provides that the amount of nuclear decommissioning costs...

10 CFR 150.21 - Transportation of special nuclear material by aircraft.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Transportation of special nuclear material by aircraft. 150.21 Section 150.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED... Transportation of special nuclear material by aircraft. Except as specifically approved by the Commission no...

10 CFR 150.21 - Transportation of special nuclear material by aircraft.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Transportation of special nuclear material by aircraft. 150.21 Section 150.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXEMPTIONS AND CONTINUED... Transportation of special nuclear material by aircraft. Except as specifically approved by the Commission no...

26 CFR 1.88-1 - Nuclear decommissioning costs.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Nuclear decommissioning costs. 1.88-1 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.88-1 Nuclear decommissioning costs. (a) In general. Section 88 provides that the amount of nuclear decommissioning costs...

Cancer Risks near Nuclear Facilities: The Importance of Research Design and Explicit Study Hypotheses

PubMed Central

Wing, Steve; Richardson, David B.; Hoffmann, Wolfgang

2011-01-01

Background In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design. Objectives We review epidemiologic principles used in studies of generic exposure–response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities. Discussion Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders. Conclusions Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes. PMID:21147606

Dynamic Nuclear Polarization NMR Spectroscopy of Polymeric Carbon Nitride Photocatalysts: Insights into Structural Defects and Reactivity.

PubMed

Li, Xiaobo; Sergeyev, Ivan V; Aussenac, Fabien; Masters, Anthony F; Maschmeyer, Thomas; Hook, James M

2018-06-04

Metal-free polymeric carbon nitrides (PCNs) are promising photocatalysts for solar hydrogen production, but their structure-photoactivity relationship remains elusive. Two PCNs were characterized by dynamic-nuclear-polarization-enhanced solid-state NMR spectroscopy, which circumvented the need for specific labeling with either 13 C- or 15 N-enriched precursors. Rapid 1D and 2D data acquisition was possible, providing insights into the structural contrasts between the PCNs. Compared to PCN_B with lower performance, PCN_P is a more porous and more active photocatalyst that is richer in terminal N-H bonds not associated with interpolymer chains. It is proposed that terminal N-H groups act as efficient carrier traps and reaction sites. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Far Field Modeling Methods For Characterizing Surface Detonations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garrett, A.

2015-10-08

Savannah River National Laboratory (SRNL) analyzed particle samples collected during experiments that were designed to replicate tests of nuclear weapons components that involve detonation of high explosives (HE). SRNL collected the particle samples in the HE debris cloud using innovative rocket propelled samplers. SRNL used scanning electronic microscopy to determine the elemental constituents of the particles and their size distributions. Depleted uranium composed about 7% of the particle contents. SRNL used the particle size distributions and elemental composition to perform transport calculations that indicate in many terrains and atmospheric conditions the uranium bearing particles will be transported long distances downwind.more » This research established that HE tests specific to nuclear proliferation should be detectable at long downwind distances by sampling airborne particles created by the test detonations.« less

Transport and fate of radionuclides in aquatic environments--the use of ecosystem modelling for exposure assessments of nuclear facilities.

PubMed

Kumblad, L; Kautsky, U; Naeslund, B

2006-01-01

In safety assessments of nuclear facilities, a wide range of radioactive isotopes and their potential hazard to a large assortment of organisms and ecosystem types over long time scales need to be considered. Models used for these purposes have typically employed approaches based on generic reference organisms, stylised environments and transfer functions for biological uptake exclusively based on bioconcentration factors (BCFs). These models are of non-mechanistic nature and involve no understanding of uptake and transport processes in the environment, which is a severe limitation when assessing real ecosystems. In this paper, ecosystem models are suggested as a method to include site-specific data and to facilitate the modelling of dynamic systems. An aquatic ecosystem model for the environmental transport of radionuclides is presented and discussed. With this model, driven and constrained by site-specific carbon dynamics and three radionuclide specific mechanisms: (i) radionuclide uptake by plants, (ii) excretion by animals, and (iii) adsorption to organic surfaces, it was possible to estimate the radionuclide concentrations in all components of the modelled ecosystem with only two radionuclide specific input parameters (BCF for plants and Kd). The importance of radionuclide specific mechanisms for the exposure to organisms was examined, and probabilistic and sensitivity analyses to assess the uncertainties related to ecosystem input parameters were performed. Verification of the model suggests that this model produces analogous results to empirically derived data for more than 20 different radionuclides.

Background staining of visualization systems in immunohistochemistry: comparison of the Avidin-Biotin Complex system and the EnVision+ system.

PubMed

Vosse, Bettine A H; Seelentag, Walter; Bachmann, Astrid; Bosman, Fred T; Yan, Pu

2007-03-01

The aim of this study was to evaluate specific immunostaining and background staining in formalin-fixed, paraffin-embedded human tissues with the 2 most frequently used immunohistochemical detection systems, Avidin-Biotin-Peroxidase (ABC) and EnVision+. A series of fixed tissues, including breast, colon, kidney, larynx, liver, lung, ovary, pancreas, prostate, stomach, and tonsil, was used in the study. Three monoclonal antibodies, 1 against a nuclear antigen (Ki-67), 1 against a cytoplasmic antigen (cytokeratin), and 1 against a cytoplasmic and membrane-associated antigen and a polyclonal antibody against a nuclear and cytoplasmic antigen (S-100) were selected for these studies. When the ABC system was applied, immunostaining was performed with and without blocking of endogenous avidin-binding activity. The intensity of specific immunostaining and the percentage of stained cells were comparable for the 2 detection systems. The use of ABC caused widespread cytoplasmic and rare nuclear background staining in a variety of normal and tumor cells. A very strong background staining was observed in colon, gastric mucosa, liver, and kidney. Blocking avidin-binding capacity reduced background staining, but complete blocking was difficult to attain. With the EnVision+ system no background staining occurred. Given the efficiency of the detection, equal for both systems or higher with EnVision+, and the significant background problem with ABC, we advocate the routine use of the EnVision+ system.

Multi-state trajectory approach to non-adiabatic dynamics: General formalism and the active state trajectory approximation

NASA Astrophysics Data System (ADS)

Tao, Guohua

2017-07-01

A general theoretical framework is derived for the recently developed multi-state trajectory (MST) approach from the time dependent Schrödinger equation, resulting in equations of motion for coupled nuclear-electronic dynamics equivalent to Hamilton dynamics or Heisenberg equation based on a new multistate Meyer-Miller (MM) model. The derived MST formalism incorporates both diabatic and adiabatic representations as limiting cases and reduces to Ehrenfest or Born-Oppenheimer dynamics in the mean-field or the single-state limits, respectively. In the general multistate formalism, nuclear dynamics is represented in terms of a set of individual state-specific trajectories, while in the active state trajectory (AST) approximation, only one single nuclear trajectory on the active state is propagated with its augmented images running on all other states. The AST approximation combines the advantages of consistent nuclear-coupled electronic dynamics in the MM model and the single nuclear trajectory in the trajectory surface hopping (TSH) treatment and therefore may provide a potential alternative to both Ehrenfest and TSH methods. The resulting algorithm features in a consistent description of coupled electronic-nuclear dynamics and excellent numerical stability. The implementation of the MST approach to several benchmark systems involving multiple nonadiabatic transitions and conical intersection shows reasonably good agreement with exact quantum calculations, and the results in both representations are similar in accuracy. The AST treatment also reproduces the exact results reasonably, sometimes even quantitatively well, with a better performance in the adiabatic representation.

Production and testing of the ENEA-Bologna VITJEFF32.BOLIB (JEFF-3.2) multi-group (199 n + 42 γ) cross section library in AMPX format for nuclear fission applications

NASA Astrophysics Data System (ADS)

Pescarini, Massimo; Orsi, Roberto; Frisoni, Manuela

2017-09-01

The ENEA-Bologna Nuclear Data Group produced the VITJEFF32.BOLIB multi-group coupled neutron/photon (199 n + 42 γ) cross section library in AMPX format, based on the OECD-NEA Data Bank JEFF-3.2 evaluated nuclear data library. VITJEFF32.BOLIB was conceived for nuclear fission applications as European counterpart of the ORNL VITAMIN-B7 similar library (ENDF/B-VII.0 data). VITJEFF32.BOLIB has the same neutron and photon energy group structure as the former ORNL VITAMIN-B6 reference library (ENDF/B-VI.3 data) and was produced using similar data processing methodologies, based on the LANL NJOY-2012.53 nuclear data processing system for the generation of the nuclide cross section data files in GENDF format. Then the ENEA-Bologna 2007 Revision of the ORNL SCAMPI nuclear data processing system was used for the conversion into the AMPX format. VITJEFF32.BOLIB contains processed cross section data files for 190 nuclides, obtained through the Bondarenko (f-factor) method for the treatment of neutron resonance self-shielding and temperature effects. Collapsed working libraries of self-shielded cross sections in FIDO-ANISN format, used by the deterministic transport codes of the ORNL DOORS system, can be generated from VITJEFF32.BOLIB through the cited SCAMPI version. This paper describes the methodology and specifications of the data processing performed and presents some results of the VITJEFF32.BOLIB validation.

Nuclear fuel performance: Trends, remedies and challenges

NASA Astrophysics Data System (ADS)

Rusch, C. A.

2008-12-01

It is unacceptable to have nuclear power plants unavailable or power restricted due to fuel reliability issues. 'Fuel reliability' has a much broader definition than just maintaining mechanical integrity and being leaker free - fuel must fully meet the specifications, impose no adverse impacts on plant operation and safety, and maintain quantifiable margins within design and operational envelopes. The fuel performance trends over the last decade are discussed and the significant contributors to reduced reliability experienced with commercial PWR and BWR designs are identified and discussed including grid-to-rod fretting and debris fretting in PWR designs and accelerated corrosion, debris fretting and pellet-cladding interaction in BWR designs. In many of these cases, the impacts have included not only fuel failures but also plant operating restrictions, forced shutdowns, and/or enhanced licensing authority oversight. Design and operational remedies are noted. The more demanding operating regimes and the constant quest to improve fuel performance require enhancements to current designs and/or new design features. Fuel users must continue to and enhance interaction with fuel suppliers in such areas as oversight of supplier design functions, lead test assembly irradiation programs and quality assurance oversight and surveillance. With the implementation of new designs and/or features, such fuel user initiatives can help to minimize the potential for performance problems.

Multiphysics Computational Analysis of a Solid-Core Nuclear Thermal Engine Thrust Chamber

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Canabal, Francisco; Cheng, Gary; Chen, Yen-Sen

2007-01-01

The objective of this effort is to develop an efficient and accurate computational heat transfer methodology to predict thermal, fluid, and hydrogen environments for a hypothetical solid-core, nuclear thermal engine - the Small Engine. In addition, the effects of power profile and hydrogen conversion on heat transfer efficiency and thrust performance were also investigated. The computational methodology is based on an unstructured-grid, pressure-based, all speeds, chemically reacting, computational fluid dynamics platform, while formulations of conjugate heat transfer were implemented to describe the heat transfer from solid to hydrogen inside the solid-core reactor. The computational domain covers the entire thrust chamber so that the afore-mentioned heat transfer effects impact the thrust performance directly. The result shows that the computed core-exit gas temperature, specific impulse, and core pressure drop agree well with those of design data for the Small Engine. Finite-rate chemistry is very important in predicting the proper energy balance as naturally occurring hydrogen decomposition is endothermic. Locally strong hydrogen conversion associated with centralized power profile gives poor heat transfer efficiency and lower thrust performance. On the other hand, uniform hydrogen conversion associated with a more uniform radial power profile achieves higher heat transfer efficiency, and higher thrust performance.

77 FR 50726 - Software Requirement Specifications for Digital Computer Software and Complex Electronics Used in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... Computer Software and Complex Electronics Used in Safety Systems of Nuclear Power Plants AGENCY: Nuclear...-1209, ``Software Requirement Specifications for Digital Computer Software and Complex Electronics used... Electronics Engineers (ANSI/IEEE) Standard 830-1998, ``IEEE Recommended Practice for Software Requirements...

10 CFR 72.26 - Contents of application: Technical specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Contents of application: Technical specifications. 72.26 Section 72.26 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

10 CFR 72.7 - Specific exemptions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Specific exemptions. 72.7 Section 72.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C WASTE General Provisions § 72.7...

10 CFR 72.7 - Specific exemptions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Specific exemptions. 72.7 Section 72.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C WASTE General Provisions § 72.7...

10 CFR 72.26 - Contents of application: Technical specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Contents of application: Technical specifications. 72.26 Section 72.26 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

10 CFR 74.7 - Specific exemptions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Specific exemptions. 74.7 Section 74.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) MATERIAL CONTROL AND ACCOUNTING OF SPECIAL NUCLEAR MATERIAL General... determines are authorized by law and will not endanger life or property or the common defense and security...

Space Nuclear Power and Propulsion: Materials Challenges for the 21st Century

NASA Technical Reports Server (NTRS)

Houts, Mike

2008-01-01

The current focus of NASA s space fission effort is Fission Surface Power (FSP). FSP systems could be used to provide power anytime, anywhere on the surface of the Moon or Mars. FSP systems could be used at locations away from the lunar poles or in permanently shaded regions, with no performance penalty. A potential reference 40 kWe option has been devised that is cost-competitive with alternatives while providing more power for less mass. The potential reference system is readily extensible for use on Mars. At Mars the system could be capable of operating through global dust storms and providing year-round power at any Martian latitude. To ensure affordability, the potential near-term, 40 kWe reference concept is designed to use only well established materials and fuels. However, if various materials challenges could be overcome, extremely high performance fission systems could be devised. These include high power, low mass fission surface power systems; in-space systems with high specific power; and high performance nuclear thermal propulsion systems. This tutorial will provide a brief overview of space fission systems and will focus on materials challenges that, if overcome, could help enable advanced exploration and utilization of the solar system.

New approaches to provide feedback from nuclear and covariance data adjustment for effective improvement of evaluated nuclear data files

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmiotti, Giuseppe; Salvatores, Massimo; Hursin, Mathieu

2016-11-01

A critical examination of the role of uncertainty assessment, target accuracies, role of integral experiment for validation and, consequently, of data adjustments methods is underway since several years at OECD-NEA, the objective being to provide criteria and practical approaches to use effectively the results of sensitivity analyses and cross section adjustments for feedback to evaluators and experimentalists in order to improve without ambiguities the knowledge of neutron cross sections, uncertainties, and correlations to be used in a wide range of applications and to meet new requirements and constraints for innovative reactor and fuel cycle system design. An approach will bemore » described that expands as much as possible the use in the adjustment procedure of selected integral experiments that provide information on “elementary” phenomena, on separated individual physics effects related to specific isotopes or on specific energy ranges. An application to a large experimental data base has been performed and the results are discussed in the perspective of new evaluation projects like the CIELO initiative.« less

New approaches to provide feedback from nuclear and covariance data adjustment for effective improvement of evaluated nuclear data files

NASA Astrophysics Data System (ADS)

Palmiotti, Giuseppe; Salvatores, Massimo; Hursin, Mathieu; Kodeli, Ivo; Gabrielli, Fabrizio; Hummel, Andrew

2017-09-01

A critical examination of the role of uncertainty assessment, target accuracies, role of integral experiment for validation and, consequently, of data adjustments methods is underway since several years at OECD-NEA, the objective being to provide criteria and practical approaches to use effectively the results of sensitivity analyses and cross section adjustments for feedback to evaluators and experimentalists in order to improve without ambiguities the knowledge of neutron cross sections, uncertainties, and correlations to be used in a wide range of applications and to meet new requirements and constraints for innovative reactor and fuel cycle system design. An approach will be described that expands as much as possible the use in the adjustment procedure of selected integral experiments that provide information on "elementary" phenomena, on separated individual physics effects related to specific isotopes or on specific energy ranges. An application to a large experimental data base has been performed and the results are discussed in the perspective of new evaluation projects like the CIELO initiative.

MELCOR simulations of the severe accident at Fukushima Daiichi Unit 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardoni, Jeffrey; Gauntt, Randall; Kalinich, Donald

In response to the accident at the Fukushima Daiichi nuclear power station in Japan, the U.S. Nuclear Regulatory Commission and U.S. Department of Energy agreed to jointly sponsor an accident reconstruction study as a means of assessing the severe accident modeling capability of the MELCOR code. Objectives of the project included reconstruction of the accident progressions using computer models and accident data, and validation of the MELCOR code and the Fukushima models against plant data. A MELCOR 2.1 model of the Fukushima Daiichi Unit 3 reactor is developed using plant-specific information and accident-specific boundary conditions, which involve considerable uncertainty duemore » to the inherent nature of severe accidents. Publicly available thermal-hydraulic data and radioactivity release estimates have evolved significantly since the accidents. Such data are expected to continually change as the reactors are decommissioned and more measurements are performed. As a result, the MELCOR simulations in this work primarily use boundary conditions that are based on available plant data as of May 2012.« less

Analysis of the Cytomorphological Features in Atypical Urine Specimens following Application of The Paris System for Reporting Urinary Cytology.

PubMed

Glass, Ryan; Rosen, Lisa; Chau, Karen; Sheikh-Fayyaz, Sylvat; Farmer, Peter; Coutsouvelis, Constantinos; Slim, Farah; Brenkert, Ryan; Das, Kasturi; Raab, Stephen; Cocker, Rubina

2018-01-01

This study investigates the use of The Paris System (TPS) for Reporting Urinary Cytopathology and examines the performance of individual and combined morphological features in atypical urine cytologies. We reviewed 118 atypical cytologies with subsequent bladder biopsies for the presence of several morphological features and reclassified them into Paris System categories. The sensitivity and specificity of individual and combined features were calculated along with the risk of malignancy. An elevated nuclear-to-cytoplasmic ratio was only predictive of malignancy if seen in single cells, while irregular nuclear borders, hyperchromasia, and coarse granular chromatin were predictive in single cells and in groups. Identification of coarse chromatin alone yielded a malignancy risk comparable to 2-feature combinations. The use of TPS criteria identified the specimens at a higher risk of malignancy. Our findings support the use of TPS criteria, suggesting that the presence of coarse chromatin is more specific than other individual features, and confirming that cytologic atypia is more worrisome in single cells than in groups. © 2017 S. Karger AG, Basel.

Nuclear Medicine Imaging of Prostate Cancer.

PubMed

Schreiter, V; Reimann, C; Geisel, D; Schreiter, N F

2016-11-01

The new tracer Gallium-68 prostate-specific membrane antigen (Ga-68 PSMA) yields new promising options for the PET/CT diagnosis of prostate cancer (PCa) and its metastases. To overcome limitations of hybrid imaging, known from the use of choline derivatives, seems to be possible with the use of Ga-68 PSMA for PCa. The benefits of hybrid imaging with Ga-68 PSMA for PCa compared to choline derivatives shall be discussed in this article based on an overview of the current literature. Key Points: • Ga-68 PSMA PET/CT can achieve higher detection rates of PCa lesions than PET/CT performed with choline derivatives• The new tracer Ga-68 PSMA has the advantage of high specificity, independence of PSA-level and low nonspecific tracer uptake in surrounding tissue• The new tracer Ga-68 PSMA seems very suitable for MR-PET diagnostic Citation Format: • Schreiter V, Reimann C, Geisel D et al. Nuclear Medicine Imaging of Prostate Cancer. Fortschr Röntgenstr 2016; 188: 1037 - 1044. © Georg Thieme Verlag KG Stuttgart · New York.

MELCOR simulations of the severe accident at Fukushima Daiichi Unit 3

DOE PAGES

Cardoni, Jeffrey; Gauntt, Randall; Kalinich, Donald; ...

2014-05-01

In response to the accident at the Fukushima Daiichi nuclear power station in Japan, the U.S. Nuclear Regulatory Commission and U.S. Department of Energy agreed to jointly sponsor an accident reconstruction study as a means of assessing the severe accident modeling capability of the MELCOR code. Objectives of the project included reconstruction of the accident progressions using computer models and accident data, and validation of the MELCOR code and the Fukushima models against plant data. A MELCOR 2.1 model of the Fukushima Daiichi Unit 3 reactor is developed using plant-specific information and accident-specific boundary conditions, which involve considerable uncertainty duemore » to the inherent nature of severe accidents. Publicly available thermal-hydraulic data and radioactivity release estimates have evolved significantly since the accidents. Such data are expected to continually change as the reactors are decommissioned and more measurements are performed. As a result, the MELCOR simulations in this work primarily use boundary conditions that are based on available plant data as of May 2012.« less

Nuclear ferritin: A new role for ferritin in cell biology.

PubMed

Alkhateeb, Ahmed A; Connor, James R

2010-08-01

Ferritin has been traditionally considered a cytoplasmic iron storage protein. However, several studies over the last two decades have reported the nuclear localization of ferritin, specifically H-ferritin, in developing neurons, hepatocytes, corneal epithelial cells, and some cancer cells. These observations encouraged a new perspective on ferritin beyond iron storage, such as a role in the regulation of iron accessibility to nuclear components, DNA protection from iron-induced oxidative damage, and transcriptional regulation. This review will address the translocation and functional significance of nuclear ferritin in the context of human development and disease. The nuclear translocation of ferritin is a selective energy-dependent process that does not seem to require a consensus nuclear localization signal. It is still unclear what regulates the nuclear import/export of ferritin. Some reports have implicated the phosphorylation and O-glycosylation of the ferritin protein in nuclear transport; others suggested the existence of a specific nuclear chaperone for ferritin. The data argue strongly for nuclear ferritin as a factor in human development and disease. Ferritin can bind and protect DNA from oxidative damage. It also has the potential of playing a regulatory role in transcription. Nuclear ferritin represents a novel new outlook on ferritin functionality beyond its classical role as an iron storage molecule. Copyright 2010 Elsevier B.V. All rights reserved.

Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley K. Heath

2014-03-01

This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show thatmore » fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.« less

Mission design considerations for nuclear risk mitigation

NASA Technical Reports Server (NTRS)

Stancati, Mike; Collins, John

1993-01-01

Strategies for the mitigation of the nuclear risk associated with two specific mission operations are discussed. These operations are the safe return of nuclear thermal propulsion reactors to earth orbit and the disposal of lunar/Mars spacecraft reactors.

Dynamic regulation of nuclear architecture and mechanics—a rheostatic role for the nucleus in tailoring cellular mechanosensitivity

PubMed Central

Lee, David A.

2017-01-01

ABSTRACT Nuclear architecture, a function of both chromatin and nucleoskeleton structure, is known to change with stem cell differentiation and differs between various somatic cell types. These changes in nuclear architecture are associated with the regulation of gene expression and genome function in a cell-type specific manner. Biophysical stimuli are known effectors of differentiation and also elicit stimuli-specific changes in nuclear architecture. This occurs via the process of mechanotransduction whereby extracellular mechanical forces activate several well characterized signaling cascades of cytoplasmic origin, and potentially some recently elucidated signaling cascades originating in the nucleus. Recent work has demonstrated changes in nuclear mechanics both with pluripotency state in embryonic stem cells, and with differentiation progression in adult mesenchymal stem cells. This review explores the interplay between cytoplasmic and nuclear mechanosensitivity, highlighting a role for the nucleus as a rheostat in tuning the cellular mechano-response. PMID:28152338

Dynamic regulation of nuclear architecture and mechanics-a rheostatic role for the nucleus in tailoring cellular mechanosensitivity.

PubMed

Thorpe, Stephen D; Lee, David A

2017-05-04

Nuclear architecture, a function of both chromatin and nucleoskeleton structure, is known to change with stem cell differentiation and differs between various somatic cell types. These changes in nuclear architecture are associated with the regulation of gene expression and genome function in a cell-type specific manner. Biophysical stimuli are known effectors of differentiation and also elicit stimuli-specific changes in nuclear architecture. This occurs via the process of mechanotransduction whereby extracellular mechanical forces activate several well characterized signaling cascades of cytoplasmic origin, and potentially some recently elucidated signaling cascades originating in the nucleus. Recent work has demonstrated changes in nuclear mechanics both with pluripotency state in embryonic stem cells, and with differentiation progression in adult mesenchymal stem cells. This review explores the interplay between cytoplasmic and nuclear mechanosensitivity, highlighting a role for the nucleus as a rheostat in tuning the cellular mechano-response.

Mathematical Modeling Of A Nuclear/Thermionic Power Source

NASA Technical Reports Server (NTRS)

Vandersande, Jan W.; Ewell, Richard C.

1992-01-01

Report discusses mathematical modeling to predict performance and lifetime of spacecraft power source that is integrated combination of nuclear-fission reactor and thermionic converters. Details of nuclear reaction, thermal conditions in core, and thermionic performance combined with model of swelling of fuel.

Nuclear weapons modernizations

NASA Astrophysics Data System (ADS)

Kristensen, Hans M.

2014-05-01

This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludes that new limits on nuclear modernizations are needed.

Deploying Nuclear Detection Systems: A Proposed Strategy for Combating Nuclear Terrorism

DTIC Science & Technology

2007-07-01

lower cost than other gamma radiation detectors (if increased count rate is all one is looking for). Low cost makes plastic scintillation detectors...material, particularly enriched uranium and plutonium, the basic fuel for nuclear bombs. • Measures to strengthen international institutions to... uranium to specifications required for a nuclear weapon.1 This illicit shipment of centrifuges was part of an international nuclear materials

NUCLEAR SCIENCE CURRICULUM PROJECT, PROJECT I, INSTRUCTIONAL SPECIFICATIONS.

ERIC Educational Resources Information Center

CAMAREN, JAMES

ON THE PREMISE THAT A KNOWLEDGE OF NUCLEAR SCIENCE IS ESSENTIAL FOR INTELLIGENT DECISION-MAKING REGARDING ITS USES, THE NUCLEAR SCIENCE CURRICULUM PROJECT WAS DEVELOPED. ITS OBJECTIVE IS TO PROVIDE A PROGRAM THAT CAN BE EFFECTIVELY USED IN SCIENCE CLASSES TO PROVIDE AN UNDERSTANDING OF NUCLEAR SCIENCE AND ITS IMPACT ON SOCIETY. THOUGH TEACHER…

Drosophila TIM Binds Importin α1, and Acts as an Adapter to Transport PER to the Nucleus

PubMed Central

Jang, A. Reum; Moravcevic, Katarina; Saez, Lino; Young, Michael W.; Sehgal, Amita

2015-01-01

Regulated nuclear entry of clock proteins is a conserved feature of eukaryotic circadian clocks and serves to separate the phase of mRNA activation from mRNA repression in the molecular feedback loop. In Drosophila, nuclear entry of the clock proteins, PERIOD (PER) and TIMELESS (TIM), is tightly controlled, and impairments of this process produce profound behavioral phenotypes. We report here that nuclear entry of PER-TIM in clock cells, and consequently behavioral rhythms, require a specific member of a classic nuclear import pathway, Importin α1 (IMPα1). In addition to IMPα1, rhythmic behavior and nuclear expression of PER-TIM require a specific nuclear pore protein, Nup153, and Ran-GTPase. IMPα1 can also drive rapid and efficient nuclear expression of TIM and PER in cultured cells, although the effect on PER is mediated by TIM. Mapping of interaction domains between IMPα1 and TIM/PER suggests that TIM is the primary cargo for the importin machinery. This is supported by attenuated interaction of IMPα1 with TIM carrying a mutation previously shown to prevent nuclear entry of TIM and PER. TIM is detected at the nuclear envelope, and computational modeling suggests that it contains HEAT-ARM repeats typically found in karyopherins, consistent with its role as a co-transporter for PER. These findings suggest that although PER is the major timekeeper of the clock, TIM is the primary target of nuclear import mechanisms. Thus, the circadian clock uses specific components of the importin pathway with a novel twist in that TIM serves a karyopherin-like role for PER. PMID:25674790

10 CFR 72.16 - Filing of application for specific license.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Filing of application for specific license. 72.16 Section 72.16 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

10 CFR 72.16 - Filing of application for specific license.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Filing of application for specific license. 72.16 Section 72.16 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

The Story of the Nuclear Rocket: Back to the Future

NASA Astrophysics Data System (ADS)

Dewar, James A.

2002-01-01

The United States had a nuclear rocket development program from 1955-1973 called Project Rover/NERVA. Twenty reactor tests demonstrated conclusively the superiority, flexibility and reliability of nuclear rocket engines over their chemical counterparts. This paper surveys the technical accomplishments from that perspective, to help illustrate why many call for the program's reestablishment. Most focus on the large NERVA, but this review will consider the little known Small Nuclear Engine. KIWI-B1B was one of the first tests in which nuclear rockets demonstrated their superiority. It ejected its core as it rose to 1000MW (a megawatt equals 50 pounds of thrust). This seems contradictory, how can a `failure' demonstrate superiority? Precisely in this: the reactor remained controllable going to and from 1000MW, still ejecting its core, but still turning out power. That gave insurance to a mission. A solid or liquid chemical engine suffering similar damage would likely shutdown or blow up. KIWI-TNT and Phoebus-1A had planned and unplanned accidents. That verified the safety of nuclear engines in launch operations. NRX/EST and XE-Prime proved they could startup reliably under their own power in a simulated space environment and change power without loss of specific impulse or control, from 20MW to 1000MW and back. That gave flexibility for mid-course corrections, maneuvering between orbits or breaking into orbit. Pewee and the Nuclear Furnace tested fuels to achieve 10 hours of engine operation with 60 recycles (stops and starts). That meant an engine could perform multiple missions. Work started on fuels promising1000 seconds of specific impulse. That meant increased power and payload capacity and speed. This contrasts with the 450 seconds of LOX/LH2. The NERVA of 1971 would be 1500MW, with 10/60 capability and 825 seconds of a specific impulse. Later generation NERVAs would be in excess of 1000 seconds, 3000MW and 10/60. The Nixon Administration cancelled it in 1971. After its demise, the Small Nuclear Engine appeared for unmanned missions. To fit in the space shuttle's 15 by 60 foot cargo bay, the 10 foot long engine would be 400MW, weigh 5600 pounds and use slush hydrogen. That left 50 feet and almost 60,000 pounds for the tank, propellant and payload that could vary in size, but it was nominally 5 tons. It would cost 500 million (in1972 dollars) and take a decade to develop. It had NERVA's operating characteristics, but subsequent generation systems envisioned longer engine life and recycle capability and specific impulses of 1000+ seconds. Nixon ended this in 1973. By reconsidering it instead of a nuclear electric engine that serves only space science, the nation could gain a fast, powerful system that would radically change most future unmanned space missions. With its recycle capability, a single engine could ferry large scientific payloads swiftly throughout the solar system. Yet it also could propel heavy national security and commercial payloads to geo-synchronous orbit. NASA might even offer a satellite retrieval service. Thus, one lesson is clear: it is 1960s era technology, but the Small Engine is not obsolete. If developed, it would serve not just one, but three users yet have growth potential for decades for an ever more expansive space program.

Nucleus-specific expression in the multinuclear mushroom-forming fungus Agaricus bisporus reveals different nuclear regulatory programs.

PubMed

Gehrmann, Thies; Pelkmans, Jordi F; Ohm, Robin A; Vos, Aurin M; Sonnenberg, Anton S M; Baars, Johan J P; Wösten, Han A B; Reinders, Marcel J T; Abeel, Thomas

2018-04-24

Many fungi are polykaryotic, containing multiple nuclei per cell. In the case of heterokaryons, there are different nuclear types within a single cell. It is unknown what the different nuclear types contribute in terms of mRNA expression levels in fungal heterokaryons. Each cell of the mushroom Agaricus bisporus contains two to 25 nuclei of two nuclear types originating from two parental strains. Using RNA-sequencing data, we assess the differential mRNA contribution of individual nuclear types and its functional impact. We studied differential expression between genes of the two nuclear types, P1 and P2, throughout mushroom development in various tissue types. P1 and P2 produced specific mRNA profiles that changed through mushroom development. Differential regulation occurred at the gene level, rather than at the locus, chromosomal, or nuclear level. P1 dominated mRNA production throughout development, and P2 showed more differentially up-regulated genes in important functional groups. In the vegetative mycelium, P2 up-regulated almost threefold more metabolism genes and carbohydrate active enzymes (cazymes) than P1, suggesting phenotypic differences in growth. We identified widespread transcriptomic variation between the nuclear types of A. bisporus Our method enables studying nucleus-specific expression, which likely influences the phenotype of a fungus in a polykaryotic stage. Our findings have a wider impact to better understand gene regulation in fungi in a heterokaryotic state. This work provides insight into the transcriptomic variation introduced by genomic nuclear separation. Copyright © 2018 the Author(s). Published by PNAS.

Worldwide measurements of radioxenon background near isotope production facilities, a nuclear power plant and at remote sites: the ‘‘EU/JA-II’’ Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saey, P. R.J.; Ringbom, Anders; Bowyer, Ted W.

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) specifies that radioxenon measurements should be performed at 40 or more stations worldwide within the International Monitoring System (IMS). Measuring radioxenon is one of the principle techniques to detect underground nuclear explosions. Specifically, presence and ratios of different radioxenon isotopes allows determining whether a detection event under consideration originated from a nuclear explosion or a civilian source. However, radioxenon monitoring on a global scale is a novel technology and the global civil background must be characterized sufficiently. This paper lays out a study, based on several unique measurement campaigns, of the worldwide concentrations and sourcesmore » of verification relevant xenon isotopes. It complements the experience already gathered with radioxenon measurements within the CTBT IMS programme and focuses on locations in Belgium, Germany, Kuwait, Thailand and South Africa where very little information was available on ambient xenon levels or interesting sites offered opportunities to learn more about emissions from known sources. The findings corroborate the hypothesis that a few major radioxenon sources contribute in great part to the global radioxenon background. Additionally, the existence of independent sources of 131mXe (the daughter of 131I) has been demonstrated, which has some potential to bias the isotopic signature of signals from nuclear explosions.« less

ApoA-II directs morphogenetic movements of zebrafish embryo by preventing chromosome fusion during nuclear division in yolk syncytial layer.

PubMed

Zhang, Ting; Yao, Shaohua; Wang, Ping; Yin, Chaoran; Xiao, Chun; Qian, Meilin; Liu, Donghui; Zheng, Lemin; Meng, Wentong; Zhu, Hongyan; Liu, Jin; Xu, Hong; Mo, Xianming

2011-03-18

The high density lipoprotein (HDL) represents a class of lipid- and protein-containing particles and consists of two major apolipoproteins apoA-I and apoA-II. ApoA-II has been shown to be involved in the pathogenesis of insulin resistance, adiposity, diabetes, and metabolic syndrome. In embryo, apoa2 mRNAs are abundant in the liver, brain, lung, placenta, and in fish yolk syncytial layer (YSL), suggesting that apoa2 may perform a function during embryonic development. Here we find out that apoa2 modulates zebrafish embryonic development by regulating the organization of YSL. Disruption of apoa2 function in zebrafish caused chromosome fusing, which strongly blocked YSL nuclear division, inducing disorders in YSL organization and finally disturbing the embryonic epiboly. Purified native human apoA-II was able specifically to rescue the defects and induced nuclear division in zebrafish embryos and in human HeLa cells. The C terminus of apoA-II was required for the proper chromosome separation during nuclear division of YSL in zebrafish embryos and in human HeLa cells. Our data indicate that organization of YSL is required for blastoderm patterning and morphogenesis and suggest that apolipoprotein apoA-II is a novel factor of nuclear division in YSL involved in the regulation of early zebrafish embryonic morphogenesis and in mammalian cells for proliferation.

ApoA-II Directs Morphogenetic Movements of Zebrafish Embryo by Preventing Chromosome Fusion during Nuclear Division in Yolk Syncytial Layer*

PubMed Central

Zhang, Ting; Yao, Shaohua; Wang, Ping; Yin, Chaoran; Xiao, Chun; Qian, Meilin; Liu, Donghui; Zheng, Lemin; Meng, Wentong; Zhu, Hongyan; Liu, Jin; Xu, Hong; Mo, Xianming

2011-01-01

The high density lipoprotein (HDL) represents a class of lipid- and protein-containing particles and consists of two major apolipoproteins apoA-I and apoA-II. ApoA-II has been shown to be involved in the pathogenesis of insulin resistance, adiposity, diabetes, and metabolic syndrome. In embryo, apoa2 mRNAs are abundant in the liver, brain, lung, placenta, and in fish yolk syncytial layer (YSL), suggesting that apoa2 may perform a function during embryonic development. Here we find out that apoa2 modulates zebrafish embryonic development by regulating the organization of YSL. Disruption of apoa2 function in zebrafish caused chromosome fusing, which strongly blocked YSL nuclear division, inducing disorders in YSL organization and finally disturbing the embryonic epiboly. Purified native human apoA-II was able specifically to rescue the defects and induced nuclear division in zebrafish embryos and in human HeLa cells. The C terminus of apoA-II was required for the proper chromosome separation during nuclear division of YSL in zebrafish embryos and in human HeLa cells. Our data indicate that organization of YSL is required for blastoderm patterning and morphogenesis and suggest that apolipoprotein apoA-II is a novel factor of nuclear division in YSL involved in the regulation of early zebrafish embryonic morphogenesis and in mammalian cells for proliferation. PMID:21212265

Nuclear localization of the dystrophin-associated protein α-dystrobrevin through importin α2/β1 is critical for interaction with the nuclear lamina/maintenance of nuclear integrity.

PubMed

Aguilar, Areli; Wagstaff, Kylie M; Suárez-Sánchez, Rocío; Zinker, Samuel; Jans, David A; Cisneros, Bulmaro

2015-05-01

Although α-dystrobrevin (DB) is assembled into the dystrophin-associated protein complex, which is central to cytoskeletal organization, it has also been found in the nucleus. Here we delineate the nuclear import pathway responsible for nuclear targeting of α-DB for the first time, together with the importance of nuclear α-DB in determining nuclear morphology. We map key residues of the nuclear localization signal of α-DB within the zinc finger domain (ZZ) using various truncated versions of the protein, and site-directed mutagenesis. Pulldown, immunoprecipitation, and AlphaScreen assays showed that the importin (IMP) α2/β1 heterodimer interacts with high affinity with the ZZ domain of α-DB. In vitro nuclear import assays using antibodies to specific importins, as well as in vivo studies using siRNA or a dominant negative importin construct, confirmed the key role of IMPα2/β1 in α-DB nuclear translocation. Knockdown of α-DB expression perturbed cell cycle progression in C2C12 myoblasts, with decreased accumulation of cells in S phase and, significantly, altered localization of lamins A/C, B1, and B2 with accompanying gross nuclear morphology defects. Because α-DB interacts specifically with lamin B1 in vivo and in vitro, nuclear α-DB would appear to play a key role in nuclear shape maintenance through association with the nuclear lamina. © FASEB.

Experimental evidence supports a sex-specific selective sieve in mitochondrial genome evolution.

PubMed

Innocenti, Paolo; Morrow, Edward H; Dowling, Damian K

2011-05-13

Mitochondria are maternally transmitted; hence, their genome can only make a direct and adaptive response to selection through females, whereas males represent an evolutionary dead end. In theory, this creates a sex-specific selective sieve, enabling deleterious mutations to accumulate in mitochondrial genomes if they exert male-specific effects. We tested this hypothesis, expressing five mitochondrial variants alongside a standard nuclear genome in Drosophila melanogaster, and found striking sexual asymmetry in patterns of nuclear gene expression. Mitochondrial polymorphism had few effects on nuclear gene expression in females but major effects in males, modifying nearly 10% of transcripts. These were mostly male-biased in expression, with enrichment hotspots in the testes and accessory glands. Our results suggest an evolutionary mechanism that results in mitochondrial genomes harboring male-specific mutation loads.

Comparison of Four Nuclear Isolation Buffers for Plant DNA Flow Cytometry

PubMed Central

LOUREIRO, JOÃO; RODRIGUEZ, ELEAZAR; DOLEŽEL, JAROSLAV; SANTOS, CONCEIÇÃO

2006-01-01

• Background and Aims DNA flow cytometry requires preparation of suspensions of intact nuclei, which are stained using a DNA-specific fluorochrome prior to analysis. Various buffer formulas were developed to preserve nuclear integrity, protect DNA from degradation and facilitate its stoichiometric staining. Although nuclear isolation buffers differ considerably in chemical composition, no systematic comparison of their performance has been made until now. This knowledge is required to select the appropriate buffer for a given species and tissue. • Methods Four common lysis buffers (Galbraith's, LB01, Otto's and Tris.MgCl2) were used to prepare samples from leaf tissues of seven plant species (Sedum burrito, Oxalis pes-caprae, Lycopersicon esculentum, Celtis australis, Pisum sativum, Festuca rothmaleri and Vicia faba). The species were selected to cover a wide range of genome sizes (1·30–26·90 pg per 2C DNA) and a variety of leaf tissue types. The following parameters were assessed: forward (FS) and side (SS) light scatters, fluorescence of propidium iodide-stained nuclei, coefficient of variation of DNA peaks, presence of debris background and the number of nuclei released from sample tissue. The experiments were performed independently by two operators and repeated on three different days. • Key Results Clear differences among buffers were observed. With the exception of O. pes-caprae, any buffer provided acceptable results for all species. LB01 and Otto's were generally the best buffers, with Otto's buffer providing better results in species with low DNA content. Galbraith's buffer led to satisfactory results and Tris.MgCl2 was generally the worst, although it yielded the best histograms in C. australis. A combined analysis of FS and SS provided a ‘fingerprint’ for each buffer. The variation between days was more significant than the variation between operators. • Conclusions Each lysis buffer tested responded to a specific problem differently and none of the buffers worked best with all species. These results expand our knowledge on nuclear isolation buffers and will facilitate selection of the most appropriate buffer depending on species, tissue type and the presence of cytosolic compounds interfering with DNA staining. PMID:16820407

Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma

NASA Technical Reports Server (NTRS)

Litchford, Ron J.; Harada, Nobuhiro

2011-01-01

Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test.

Nuclear transporters in a multinucleated organism: functional and localization analyses in Aspergillus nidulans

PubMed Central

Markina-Iñarrairaegui, Ane; Etxebeste, Oier; Herrero-García, Erika; Araújo-Bazán, Lidia; Fernández-Martínez, Javier; Flores, Jairo A.; Osmani, Stephen A.; Espeso, Eduardo A.

2011-01-01

Nuclear transporters mediate bidirectional macromolecule traffic through the nuclear pore complex (NPC), thus participating in vital processes of eukaryotic cells. A systematic functional analysis in Aspergillus nidulans permitted the identification of 4 essential nuclear transport pathways of a hypothetical number of 14. The absence of phenotypes for most deletants indicates redundant roles for these nuclear receptors. Subcellular distribution studies of these carriers show three main distributions: nuclear, nucleocytoplasmic, and in association with the nuclear envelope. These locations are not specific to predicted roles as exportins or importins but indicate that bidirectional transport may occur coordinately in all nuclei of a syncytium. Coinciding with mitotic NPC rearrangements, transporters dynamically modified their localizations, suggesting supplementary roles to nucleocytoplasmic transport specifically during mitosis. Loss of transportin-SR and Mex/TAP from the nuclear envelope indicates absence of RNA transport during the partially open mitosis of Aspergillus, whereas nucleolar accumulation of Kap121 and Kap123 homologues suggests a role in nucleolar disassembly. This work provides new insight into the roles of nuclear transporters and opens an avenue for future studies of the molecular mechanisms of transport among nuclei within a common cytoplasm, using A. nidulans as a model organism. PMID:21880896

Technical Letter Report: Evaluation and Analysis of a Few International Periodic Safety Review Summary Reports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chopra, Omesh K.; Diercks, Dwight R.; Ma, David Chia-Chiun

At the request of the United States (U.S.) government, the International Atomic Energy Agency (IAEA) assembled a team of 20 senior safety experts to review the regulatory framework for the safety of operating nuclear power plants in the United States. This review focused on the effectiveness of the regulatory functions implemented by the NRC and on its commitment to nuclear safety and continuous improvement. One suggestion resulting from that review was that the U.S. Nuclear Regulatory Commission (NRC) incorporate lessons learned from periodic safety reviews (PSRs) performed in other countries as an input to the NRC’s assessment processes. In themore » U.S., commercial nuclear power plants (NPPs) are granted an initial 40-year operating license, which may be renewed for additional 20-year periods, subject to complying with regulatory requirements. The NRC has established a framework through its inspection, and operational experience processes to ensure the safe operation of licensed nuclear facilities on an ongoing basis. In contrast, most other countries do not impose a specific time limit on the operating licenses for NPPs, they instead require that the utility operating the plant perform PSRs, typically at approximately 10-year intervals, to assure continued safe operation until the next assessment. The staff contracted with Argonne National Laboratory (Argonne) to perform a pilot review of selected translated PSR assessment reports and related documentation from foreign nuclear regulatory authorities to identify any potential new regulatory insights regarding license renewal-related topics and NPP operating experience (OpE). A total of 14 PSR assessment documents from 9 countries were reviewed. For all of the countries except France, individual reports were provided for each of the plants reviewed. In the case of France, three reports were provided that reviewed the performance assessment of thirty-four 900-MWe reactors of similar design commissioned between 1978 and 1988. All of the reports reviewed were the regulator’s assessment of the PSR findings rather than the original PSR report, and all but one were English translations from the original language. In these reviews, it was found that most of the countries base their regulatory guidance to some extent (and often to a large extent) on U.S. design codes and standards, NRC regulatory guidance, and U.S. industry guidance. In addition, many of the observed operational technical issues and OpE events reported for U.S. reactors are also cited in the PSR reports. The PSR reports also identified a number of potential technical material/component performance issues and OpE events that are not commonly reported for U.S. plants.« less

76 FR 57980 - Senior Executive Service Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-19

... DEFENSE NUCLEAR FACILITIES SAFETY BOARD Senior Executive Service Performance Review Board AGENCY... the Defense Nuclear Facilities Safety Board (DNFSB) Senior Executive Service (SES) Performance Review... summary rating of the senior executive's performance, the executive's response, and the higher level...

77 FR 54570 - Senior Executive Service Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-05

... DEFENSE NUCLEAR FACILITIES SAFETY BOARD Senior Executive Service Performance Review Board AGENCY... the Defense Nuclear Facilities Safety Board (DNFSB) Senior Executive Service (SES) Performance Review.... The PRB shall review and evaluate the initial summary rating of the senior executive's performance...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unterberger, Claudia; Hanson, Steven; Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 9HN

Little is known about determinants regulating expression of Mannan-binding lectin associated serine protease-2 (MASP-2), the effector component of the lectin pathway of complement activation. Comparative bioinformatic analysis of the MASP2 promoter regions in human, mouse, and rat, revealed conservation of two putative Stat binding sites, termed StatA and StatB. Site directed mutagenesis specific for these sites was performed. Transcription activity was decreased 5-fold when StatB site was mutated in the wildtype reporter gene construct. Gel retardation and competition assays demonstrated that proteins contained in the nuclear extract prepared from HepG2 specifically bound double-stranded StatB oligonucleotides. Supershift analysis revealed Stat3 tomore » be the major specific binding protein. We conclude that Stat3 binding is important for MASP2 promoter activity.« less

Nuclear Data Activities in Support of the DOE Nuclear Criticality Safety Program

NASA Astrophysics Data System (ADS)

Westfall, R. M.; McKnight, R. D.

2005-05-01

The DOE Nuclear Criticality Safety Program (NCSP) provides the technical infrastructure maintenance for those technologies applied in the evaluation and performance of safe fissionable-material operations in the DOE complex. These technologies include an Analytical Methods element for neutron transport as well as the development of sensitivity/uncertainty methods, the performance of Critical Experiments, evaluation and qualification of experiments as Benchmarks, and a comprehensive Nuclear Data program coordinated by the NCSP Nuclear Data Advisory Group (NDAG). The NDAG gathers and evaluates differential and integral nuclear data, identifies deficiencies, and recommends priorities on meeting DOE criticality safety needs to the NCSP Criticality Safety Support Group (CSSG). Then the NDAG identifies the required resources and unique capabilities for meeting these needs, not only for performing measurements but also for data evaluation with nuclear model codes as well as for data processing for criticality safety applications. The NDAG coordinates effort with the leadership of the National Nuclear Data Center, the Cross Section Evaluation Working Group (CSEWG), and the Working Party on International Evaluation Cooperation (WPEC) of the OECD/NEA Nuclear Science Committee. The overall objective is to expedite the issuance of new data and methods to the DOE criticality safety user. This paper describes these activities in detail, with examples based upon special studies being performed in support of criticality safety for a variety of DOE operations.

Nuclear Forensic Inferences Using Iterative Multidimensional Statistics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robel, M; Kristo, M J; Heller, M A

2009-06-09

Nuclear forensics involves the analysis of interdicted nuclear material for specific material characteristics (referred to as 'signatures') that imply specific geographical locations, production processes, culprit intentions, etc. Predictive signatures rely on expert knowledge of physics, chemistry, and engineering to develop inferences from these material characteristics. Comparative signatures, on the other hand, rely on comparison of the material characteristics of the interdicted sample (the 'questioned sample' in FBI parlance) with those of a set of known samples. In the ideal case, the set of known samples would be a comprehensive nuclear forensics database, a database which does not currently exist. Inmore » fact, our ability to analyze interdicted samples and produce an extensive list of precise materials characteristics far exceeds our ability to interpret the results. Therefore, as we seek to develop the extensive databases necessary for nuclear forensics, we must also develop the methods necessary to produce the necessary inferences from comparison of our analytical results with these large, multidimensional sets of data. In the work reported here, we used a large, multidimensional dataset of results from quality control analyses of uranium ore concentrate (UOC, sometimes called 'yellowcake'). We have found that traditional multidimensional techniques, such as principal components analysis (PCA), are especially useful for understanding such datasets and drawing relevant conclusions. In particular, we have developed an iterative partial least squares-discriminant analysis (PLS-DA) procedure that has proven especially adept at identifying the production location of unknown UOC samples. By removing classes which fell far outside the initial decision boundary, and then rebuilding the PLS-DA model, we have consistently produced better and more definitive attributions than with a single pass classification approach. Performance of the iterative PLS-DA method compared favorably to that of classification and regression tree (CART) and k nearest neighbor (KNN) algorithms, with the best combination of accuracy and robustness, as tested by classifying samples measured independently in our laboratories against the vendor QC based reference set.« less

10 CFR 73.20 - General performance objective and requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false General performance objective and requirements. 73.20 Section 73.20 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS... special nuclear material; takes delivery of formula quantities of strategic special nuclear material free...

10 CFR 73.20 - General performance objective and requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false General performance objective and requirements. 73.20 Section 73.20 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS... special nuclear material; takes delivery of formula quantities of strategic special nuclear material free...

10 CFR 73.20 - General performance objective and requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false General performance objective and requirements. 73.20 Section 73.20 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS... special nuclear material; takes delivery of formula quantities of strategic special nuclear material free...

10 CFR 73.20 - General performance objective and requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false General performance objective and requirements. 73.20 Section 73.20 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS... special nuclear material; takes delivery of formula quantities of strategic special nuclear material free...

Nuclear technologies for explosives detection

NASA Astrophysics Data System (ADS)

Bell, Curtis J.

1992-12-01

This paper presents an exploration of several techniques for detection of Improvised Explosive Devices (IED) using interactions of specific nuclei with gammarays or fast neutrons. Techniques considered use these interactions to identify the device by measuring the densities and/or relative concentrations of the elemental constituents of explosives. These techniques are to be compared with selected other nuclear and non-nuclear methods. Combining of nuclear and non-nuclear techniques will also be briefly discussed.

Phospholipid Regulation of the Nuclear Receptor Superfamily

PubMed Central

Crowder, Mark K.; Seacrist, Corey D.; Blind, Raymond D.

2016-01-01

Nuclear receptors are ligand-activated transcription factors whose diverse biological functions are classically regulated by cholesterol-based small molecules. Over the past few decades, a growing body of evidence has demonstrated that phospholipids and other similar amphipathic molecules can also specifically bind and functionally regulate the activity of certain nuclear receptors, suggesting a critical role for these non-cholesterol-based molecules in transcriptional regulation. Phosphatidylcholines, phosphoinositides and sphingolipids are a few of the many phospholipid like molecules shown to quite specifically regulate nuclear receptors in mouse models, cell lines and in vitro. More recent evidence has also shown that certain nuclear receptors can “present” a bound phospholipid headgroup to key lipid signaling enzymes, which can then modify the phospholipid headgroup with very unique kinetic properties. Here, we review the broad array of phospholipid / nuclear receptor interactions, from the perspective of the chemical nature of the phospholipid, and the cellular abundance of the phospholipid. We also view the data in the light of well established paradigms for phospholipid mediated transcriptional regulation, as well as newer models of how phospholipids might effect transcription in the acute regulation of complex nuclear signaling pathways. Thus, this review provides novel insight into the new, non-membrane associated roles nuclear phospholipids play in regulating complex nuclear events, centered on the nuclear receptor superfamily of transcription factors. PMID:27838257

Imaging analysis of nuclear antiviral factors through direct detection of incoming adenovirus genome complexes.

PubMed

Komatsu, Tetsuro; Will, Hans; Nagata, Kyosuke; Wodrich, Harald

2016-04-22

Recent studies involving several viral systems have highlighted the importance of cellular intrinsic defense mechanisms through nuclear antiviral proteins that restrict viral propagation. These factors include among others components of PML nuclear bodies, the nuclear DNA sensor IFI16, and a potential restriction factor PHF13/SPOC1. For several nuclear replicating DNA viruses, it was shown that these factors sense and target viral genomes immediately upon nuclear import. In contrast to the anticipated view, we recently found that incoming adenoviral genomes are not targeted by PML nuclear bodies. Here we further explored cellular responses against adenoviral infection by focusing on specific conditions as well as additional nuclear antiviral factors. In line with our previous findings, we show that neither interferon treatment nor the use of specific isoforms of PML nuclear body components results in co-localization between incoming adenoviral genomes and the subnuclear domains. Furthermore, our imaging analyses indicated that neither IFI16 nor PHF13/SPOC1 are likely to target incoming adenoviral genomes. Thus our findings suggest that incoming adenoviral genomes may be able to escape from a large repertoire of nuclear antiviral mechanisms, providing a rationale for the efficient initiation of lytic replication cycle. Copyright © 2016 Elsevier Inc. All rights reserved.

Status of Low Thrust Work at JSC

NASA Technical Reports Server (NTRS)

Condon, Gerald L.

2004-01-01

High performance low thrust (solar electric, nuclear electric, variable specific impulse magnetoplasma rocket) propulsion offers a significant benefit to NASA missions beyond low Earth orbit. As NASA (e.g., Prometheus Project) endeavors to develop these propulsion systems and associated power supplies, it becomes necessary to develop a refined trajectory design capability that will allow engineers to develop future robotic and human mission designs that take advantage of this new technology. This ongoing work addresses development of a trajectory design and optimization tool for assessing low thrust (and other types) trajectories. This work targets to advance the state of the art, enable future NASA missions, enable science drivers, and enhance education. This presentation provides a summary of the low thrust-related JSC activities under the ISP program and specifically, provides a look at a new release of a multi-gravity, multispacecraft trajectory optimization tool (Copernicus) along with analysis performed using this tool over the past year.

0610009K11Rik, a testis-specific and germ cell nuclear receptor-interacting protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Heng; Denhard, Leslie A.; Zhou Huaxin

Using an in silico approach, a putative nuclear receptor-interacting protein 0610009K11Rik was identified in mouse testis. We named this gene testis-specific nuclear receptor-interacting protein-1 (Tnrip-1). Tnrip-1 was predominantly expressed in the testis of adult mouse tissues. Expression of Tnrip-1 in the testis was regulated during postnatal development, with robust expression in 14-day-old or older testes. In situ hybridization analyses showed that Tnrip-1 is highly expressed in pachytene spermatocytes and spermatids. Consistent with its mRNA expression, Tnrip-1 protein was detected in adult mouse testes. Immunohistochemical studies showed that Tnrip-1 is a nuclear protein and mainly expressed in pachytene spermatocytes and roundmore » spermatids. Moreover, co-immunoprecipitation analyses showed that endogenous Tnrip-1 protein can interact with germ cell nuclear receptor (GCNF) in adult mouse testes. Our results suggest that Tnrip-1 is a testis-specific and GCNF-interacting protein which may be involved in the modulation of GCNF-mediated gene transcription in spermatogenic cells within the testis.« less

Proliferation-dependent positioning of individual centromeres in the interphase nucleus of human lymphoblastoid cell lines

PubMed Central

Ollion, Jean; Loll, François; Cochennec, Julien; Boudier, Thomas; Escudé, Christophe

2015-01-01

The cell nucleus is a highly organized structure and plays an important role in gene regulation. Understanding the mechanisms that sustain this organization is therefore essential for understanding genome function. Centromeric regions (CRs) of chromosomes have been known for years to adopt specific nuclear positioning patterns, but the significance of this observation is not yet completely understood. Here, using a combination of fluorescence in situ hybridization and immunochemistry on fixed human cells and high-throughput imaging, we directly and quantitatively investigated the nuclear positioning of specific human CRs. We observe differential attraction of individual CRs toward both the nuclear border and the nucleoli, the former being enhanced in nonproliferating cells and the latter being enhanced in proliferating cells. Similar positioning patterns are observed in two different lymphoblastoid cell lines. Moreover, the positioning of CRs differs from that of noncentromeric regions, and CRs display specific orientations within chromosome territories. These results suggest the existence of not-yet-characterized mechanisms that drive the nuclear positioning of CRs and therefore pave the way toward a better understanding of how CRs affect nuclear organization. PMID:25947134

Nuclear winter - Physics and physical mechanisms

NASA Technical Reports Server (NTRS)

Turco, R. P.; Toon, O. B.; Pollack, J. B.; Ackerman, T. P.; Sagan, C.

1991-01-01

The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples.

78 FR 77508 - Duke Energy Carolinas, LLC; William States Lee III Nuclear Station, Units 1 and 2; Combined...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-23

..., LLC; William States Lee III Nuclear Station, Units 1 and 2; Combined Licenses Application Review... Environmental Impact Statement [EIS] for Combined Licenses (COLs) for William States Lee III Nuclear Station... be accessed online at the NRC's William States Lee III Nuclear Station--specific Web page at: www.nrc...

75 FR 56999 - Senior Executive Service Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-17

... DEFENSE NUCLEAR FACILITIES SAFETY BOARD Senior Executive Service Performance Review Board AGENCY... the Defense Nuclear Facilities Safety Board (DNFSB) Senior Executive Service (SES) Performance Review... performance review boards. The PRB shall review and evaluate the initial summary rating of the senior...

76 FR 66332 - Appointments to Performance Review Boards for Senior Executive Service

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-26

... NUCLEAR REGULATORY COMMISSION [NRC-2011-0249] Appointments to Performance Review Boards for Senior Executive Service AGENCY: U.S. Nuclear Regulatory Commission. ACTION: Appointment to Performance Review... the following appointments to the NRC Performance Review Boards. The following individuals are...

Measuring topology of low-intensity DNA methylation sites for high-throughput assessment of epigenetic drug-induced effects in cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gertych, Arkadiusz, E-mail: gertycha@cshs.org; Bioinformatics, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA; Farkas, Daniel L., E-mail: dlfarkas@gmail.com

2010-11-15

Epigenetic anti-cancer drugs with demethylating effects have shown to alter genome organization in mammalian cell nuclei. The interest in the development of novel epigenetic drugs has increased the demand for cell-based assays to evaluate drug performance in pre-clinical studies. An imaging-based cytometrical approach that can measure demethylation effects as changes in the spatial nuclear distributions of methylated cytosine and global DNA in cancer cells is introduced in this paper. The cells were studied by immunofluorescence with a specific antibody against 5-methylcytosine (MeC), and 4,6-diamidino-2-phenylindole (DAPI) for delineation of methylated sites and global DNA in nuclei. In the preprocessing step themore » segmentation of nuclei in three-dimensional images (3-D) is followed by an automated assessment of nuclear DAPI/MeC patterns to exclude dissimilar entities. Next, low-intensity MeC (LIM) and low-intensity DNA (LID) sites of similar nuclei are localized and processed to obtain specific nuclear density profiles. These profiles sampled at half of the total nuclear volume yielded two parameters: LIM{sub 0.5} and LID{sub 0.5}. The analysis shows that zebularine and 5-azacytidine-the two tested epigenetic drugs introduce changes in the spatial distribution of low-intensity DNA and MeC signals. LIM{sub 0.5} and LID{sub 0.5} were significantly different (p < 0.001) in 5-azacytidine treated (n = 660) and zebularine treated (n = 496) vs. untreated (n = 649) DU145 human prostate cancer cells. In the latter case the LIM sites were predominantly found at the nuclear border, whereas treated populations showed different degrees of increase in LIMs towards the interior nuclear space, in which a large portion of heterochromatin is located. The cell-by-cell evaluation of changes in the spatial reorganization of MeC/DAPI signals revealed that zebularine is a more gentle demethylating agent than 5-azacytidine. Measuring changes in the topology of low-intensity sites can potentially be a valuable component in the high-throughput assessment of demethylation and risk of chromatin reorganization in epigenetic-drug screening tasks.« less

Nuclear weapons modernizations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristensen, Hans M.

This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludesmore » that new limits on nuclear modernizations are needed.« less

Use of multiscale zirconium alloy deformation models in nuclear fuel behavior analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery, Robert; Tomé, Carlos; Liu, Wenfeng

Accurate prediction of cladding mechanical behavior is a key aspect of modeling nuclear fuel behavior, especially for conditions of pellet-cladding interaction (PCI), reactivity-initiated accidents (RIA), and loss of coolant accidents (LOCA). Current approaches to fuel performance modeling rely on empirical models for cladding creep, growth and plastic deformation, which are limited to the materials and conditions for which the models were developed. CASL has endeavored to improve upon this approach by incorporating a microstructurally-based, atomistically-informed, zirconium alloy mechanical deformation analysis capability into the BISON-CASL engineering scale fuel performance code. Specifically, the viscoplastic self-consistent (VPSC) polycrystal plasticity modeling approach, developed bymore » Lebensohn and Tome´ [2], has been coupled with BISON-CASL to represent the mechanistic material processes controlling the deformation behavior of the cladding. A critical component of VPSC is the representation of the crystallographic orientation of the grains within the matrix material and the ability to account for the role of texture on deformation. The multiscale modeling of cladding deformation mechanisms allowed by VPSC far exceed the functionality of typical semi-empirical constitutive models employed in nuclear fuel behavior codes to model irradiation growth and creep, thermal creep, or plasticity. This paper describes the implementation of an interface between VPSC and BISON-CASL and provides initial results utilizing the coupled functionality.« less

Analysis of an open cycle gas core nuclear propulsion system using MHD driven vortices for fuel containment

NASA Astrophysics Data System (ADS)

Sedwick, Raymond John

1998-12-01

A novel method for containing gaseous uranium vapor in an open cycle nuclear space propulsion system is developed. In an attempt to increase the operating temperature of the nuclear reactor beyond the melting point of solid fuel rods (thus increasing specific impulse), the fuel is instead suspended as a vapor in the propellant using the pressure forces developed in a confined vortex flow. The introduction of the fuel as uranium hexafluoride is found to be effective in maintaining its vapor phase in the feed passages from the tank, but not in the main vortex. A mechanism by which the resulting condensation of the uranium may be tolerated is identified, and the electro- optical properties of the resulting mixture are investigated. Containment is modeled using a 1D- axisymmetric geometry, and radiative heat transfer is found to restrict the maximum specific impulse of the system to 1500 seconds using pumping pressures of 500 atm. The specific impulse is related to this pressure as pm1/4, allowing only marginal increases in Isp at increased pressure levels. Additional 2D- axisymmetric issues, such as non-uniform current distribution and bypass flows through the boundary layers, are investigated, with possible methods of solution cited. A two-group, two-region reactor analysis is performed, estimating the mass of the reactor to be about 10 metric tonnes, and establishing the thrust to weight ratio achievable by the system at about 50. To reduce the mass of the power system, a scheme for using cross-flow heat exchange with the propellant flow to minimize (and possibly eliminate) the need for radiators to reject waste heat is presented. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Development of a patient-specific dosimetry estimation system in nuclear medicine examination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, H. H.; Dong, S. L.; Yang, H. J.

2011-07-01

The purpose of this study is to develop a patient-specific dosimetry estimation system in nuclear medicine examination using a SimSET-based Monte Carlo code. We added a dose deposition routine to store the deposited energy of the photons during their flights in SimSET and developed a user-friendly interface for reading PET and CT images. Dose calculated on ORNL phantom was used to validate the accuracy of this system. The S values for {sup 99m}Tc, {sup 18}F and {sup 131}I obtained by the system were compared to those from the MCNP4C code and OLINDA. The ratios of S values computed by thismore » system to those obtained with OLINDA for various organs were ranged from 0.93 to 1.18, which are comparable to that obtained from MCNP4C code (0.94 to 1.20). The average ratios of S value were 0.99{+-}0.04, 1.03{+-}0.05, and 1.00{+-}0.07 for isotopes {sup 131}I, {sup 18}F, and {sup 99m}Tc, respectively. The simulation time of SimSET was two times faster than MCNP4C's for various isotopes. A 3D dose calculation was also performed on a patient data set with PET/CT examination using this system. Results from the patient data showed that the estimated S values using this system differed slightly from those of OLINDA for ORNL phantom. In conclusion, this system can generate patient-specific dose distribution and display the isodose curves on top of the anatomic structure through a friendly graphic user interface. It may also provide a useful tool to establish an appropriate dose-reduction strategy to patients in nuclear medicine environments. (authors)« less

New French Regulation for NPPs and Code Consequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faidy, Claude

2006-07-01

On December 2005, the French regulator issued a new regulation for French nuclear power plants, in particular for pressure equipment (PE). This regulation need first to agree with non-nuclear PE regulation and add to that some specific requirements, in particular radiation protection requirements. Different advantages are in these proposal, it's more qualitative risk oriented and it's an important link with non-nuclear industry. Only few components are nuclear specific. But, the general philosophy of the existing Codes (RCC-M [15], KTA [16] or ASME [17]) have to be improved. For foreign Codes, it's plan to define the differences in the user specifications.more » In parallel to that, a new safety classification has been developed by French utility. The consequences is the need to cross all these specifications to define a minimum quality level for each components or systems. In the same time a new concept has been developed to replace the well known 'Leak Before Break methodology': the 'Break Exclusion' methodology. This paper will summarize the key aspects of these different topics. (authors)« less

Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Phase II Upgrade Activities

NASA Technical Reports Server (NTRS)

Emrich, William J.; Moran, Robert P.; Pearson, J. Bose

2013-01-01

To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities. Keywords: Nuclear Thermal Propulsion, Simulator

Poster — Thur Eve — 54: Radiotherapy and Non-Radiotherapy Safety Practices Beyond Licensing Expectations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kosierb, Rick

The Canadian Nuclear Safety Commission (CNSC) regulates the use of nuclear energy and materials to protect the health, safety and security of Canadians and the environment, and to implement Canada's international obligations on the peaceful use of nuclear energy. In order to perform this regulatory activity, the CNSC issue licences and has its staff perform inspections to verify conformity to the aspects of those licences. Within the CNSC, the Accelerators and Class II Facilities Division (ACFD) is responsible for the regulatory oversight of Class II Prescribed Equipment used in medical, academic, and industrial sectors in Canada. In performing inspections, ACFDmore » has encountered licensees with practices that are either below, meet or exceed regulatory expectations in specific areas. Unfortunately, none of these practices are ever communicated to the broader Class II community to help other licensees avoid the same problem or achieve high standards. In this poster, ACFD will highlight safety practices that go beyond expectations. These practices are taken from observations during site inspections between 2007 and 2013 and will be presented in six areas: Procedures, Participation, Awareness, Equipment, Servicing and Software. Each area briefly discusses a number of practices that the CNSC feels went beyond the expectations dictated by the licence. Where possible, names are added of the contact people at the centres who can be reached for full details of their implementations. It is hoped that this communication will assist other licensees to achieve these same high levels of compliance and possibly go beyond.« less

SU-F-T-298: The Impact of Modeling the Treatment Couch On Patient Specific VMAT QA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelover, E; Dalhart, A; Hyer, D

2016-06-15

Purpose: The aim of this work is to quantify the impact of modeling the treatment couch on the passing rate of ion chamber measurements during VMAT quality assurance. Methods: For the initial characterization, attenuation and surface dose measurements were performed following the guidelines of TG-176 for the Civco Universal couch top using an Elekta VersaHD accelerator at an energy of 6 MV. A simulation CT was performed to aid in the creation of contours for representing the shape and size of the couch top in the treatment planning system (TPS). A uniform value of density for the couch wall wasmore » determined by comparing the ratios of ion chamber measurements made in a 30×30×11 cm3 water phantom with the TPS dose values of a plan with the same geometry. At our institution, patient specific quality assurance is performed using a Sun Nuclear ArcCheck with a multi-plug for chamber measurements, a 0.125cc PTW TN31010 chamber, and a Sun Nuclear 1010 electrometer. Ten VMAT plans were transferred into the phantom geometry created in the TPS with two settings: with and without the couch. The chamber measurements were compared to both treatment plans. Results: A maximum attenuation of 3.6% was observed when the gantry angle was set to 120 and 240 degrees, passing obliquely through the couch. A uniform density of 0.6 g/cm3 for the couch wall was determined in the TPS by comparison with measured data. The VMAT ion chamber measurement/plan ratios systematically improved by 1.79% ±0.53% for all patients when the couch was included in the calculation. Conclusion: The attenuation and surface dose changes produced by the Civco couch can generate observable dose difference in VMAT plans. Including a couch model in the phantom plan used for patient specific VMAT QA can improve the ionization chamber agreement by up to ∼2%.« less

The Guardian: The Source for Antiterrorism Information. Volume 9, Number 1, April 2007

DTIC Science & Technology

2007-04-01

the fuel in these research reactors is generally not highly radioactive . Unlike the fuel rods in a nuclear power plant, these fuel elements would...NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND...practices and lessons learned. In addition, we will include Service and issue-specific breakout sessions that will focus on critical AT program elements

Defense Civil Support: DOD Has Made Progress Incorporating the Homeland Response Force into the Chemical, Biological, Radiological, and Nuclear Response Enterprise

DTIC Science & Technology

2016-06-01

Weapons of Mass Destruction: Additional Steps Could Enhance the Effectiveness of the National Guard’s Life- Saving Response Forces, GAO-12-114...perform its mission to save lives and reduce human suffering. The Defense Readiness Reporting System consists of two parts—a rating on whether the HRF is...plans. 28Three HRF Commanders reported that additional personnel are trained or vaccinated , but did not provide a specific percentage of additional

78 FR 61400 - Entergy Nuclear Operations, Inc., Pilgrim Nuclear Power Station, Issuance of Director's Decision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-03

... Nuclear Operations, Inc., Pilgrim Nuclear Power Station, Issuance of Director's Decision Notice is hereby... ML102210411, respectively), concerns the operation of Pilgrim Nuclear Power Station (Pilgrim), owned by...) inaccessible cables at Pilgrim Nuclear Power Station (Pilgrim) are capable of performing their required...

The 2011 nuclear medicine technology job analysis project of the American Registry of Radiologic Technologists.

PubMed

Anderson, Dan; Hubble, William; Press, Bret A; Hall, Scott K; Michels, Ann D; Koenen, Roxanne; Vespie, Alan W

2010-12-01

The American Registry of Radiologic Technologists (ARRT) conducts periodic job analysis projects to update the content and eligibility requirements for all certification examinations. In 2009, the ARRT conducted a comprehensive job analysis project to update the content specifications and clinical competency requirements for the nuclear medicine technology examination. ARRT staff and a committee of volunteer nuclear medicine technologists designed a job analysis survey that was sent to a random sample of 1,000 entry-level staff nuclear medicine technologists. Through analysis of the survey data and judgments of the committee, the project resulted in changes to the nuclear medicine technology examination task list, content specifications, and clinical competency requirements. The primary changes inspired by the project were the introduction of CT content to the examination and the expansion of the content covering cardiac procedures.

Nuclear mtDNA pseudogenes as a source of new variants of mitochondrial genes: A case study of Siberian rubythroat Luscinia calliope (muscicapidae, aves).

PubMed

Spiridonova, L N; Red'kin, Ya A; Valchuk, O P

2016-01-01

First evidence for the presence of copies of mitochondrial cytochrome b gene of the subspecies group Luscinia calliope anadyrensis-L. c. camtschatkensis in the nuclear genome of nominative L. c. calliope was obtained, which indirectly indicates the nuclear origin of the subspecies-specific mitochondrial haplotypes in Siberian rubythroat. This fact clarifies the appearance of mitochondrial haplotypes of eastern subspecies by exchange between the homologous regions of the nuclear and mitochondrial genomes followed by fixation by the founder effect. This is the first study to propose a mechanism of DNA fragment exchange between the nucleus and mitochondria (intergenomic recombination) and to show the role of nuclear copies of mtDNA as a source of new taxon-specific mitochondrial haplotypes, which implies their involvement in the microevolutionary processes and morphogenesis.

A unique nuclear thermal rocket engine using a particle bed reactor

NASA Astrophysics Data System (ADS)

Culver, Donald W.; Dahl, Wayne B.; McIlwain, Melvin C.

1992-01-01

Aerojet Propulsion Division (APD) studied 75-klb thrust Nuclear Thermal Rocket Engines (NTRE) with particle bed reactors (PBR) for application to NASA's manned Mars mission and prepared a conceptual design description of a unique engine that best satisfied mission-defined propulsion requirements and customer criteria. This paper describes the selection of a sprint-type Mars transfer mission and its impact on propulsion system design and operation. It shows how our NTRE concept was developed from this information. The resulting, unusual engine design is short, lightweight, and capable of high specific impulse operation, all factors that decrease Earth to orbit launch costs. Many unusual features of the NTRE are discussed, including nozzle area ratio variation and nozzle closure for closed loop after cooling. Mission performance calculations reveal that other well known engine options do not support this mission.

Nuclear quantum effect with pure anharmonicity and the anomalous thermal expansion of silicon.

PubMed

Kim, D S; Hellman, O; Herriman, J; Smith, H L; Lin, J Y Y; Shulumba, N; Niedziela, J L; Li, C W; Abernathy, D L; Fultz, B

2018-02-27

Despite the widespread use of silicon in modern technology, its peculiar thermal expansion is not well understood. Adapting harmonic phonons to the specific volume at temperature, the quasiharmonic approximation, has become accepted for simulating the thermal expansion, but has given ambiguous interpretations for microscopic mechanisms. To test atomistic mechanisms, we performed inelastic neutron scattering experiments from 100 K to 1,500 K on a single crystal of silicon to measure the changes in phonon frequencies. Our state-of-the-art ab initio calculations, which fully account for phonon anharmonicity and nuclear quantum effects, reproduced the measured shifts of individual phonons with temperature, whereas quasiharmonic shifts were mostly of the wrong sign. Surprisingly, the accepted quasiharmonic model was found to predict the thermal expansion owing to a large cancellation of contributions from individual phonons.

Analysis of sheltering and evacuation strategies for a Chicago nuclear detonation scenario.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshimura, Ann S.; Brandt, Larry D.

2011-09-01

Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kt detonation in Chicago. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternatives at selected exemplarymore » points. For many Chicago neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.« less

22 CFR 129.7 - Prior approval (license).

Code of Federal Regulations, 2010 CFR

2010-04-01

...; (ii) Nuclear weapons strategic delivery systems and all components, parts, accessories, attachments specifically designed for such systems and associated equipment; (iii) Nuclear weapons design and test equipment of a nature described by Category XVI of Part 121; (iv) Naval nuclear propulsion equipment of a...

22 CFR 129.7 - Prior approval (license).

Code of Federal Regulations, 2011 CFR

2011-04-01

...; (ii) Nuclear weapons strategic delivery systems and all components, parts, accessories, attachments specifically designed for such systems and associated equipment; (iii) Nuclear weapons design and test equipment of a nature described by Category XVI of part 121; (iv) Naval nuclear propulsion equipment of a...

78 FR 70079 - Appointments to Performance Review Boards for Senior Executive Service

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

... NUCLEAR REGULATORY COMMISSION [NRC-2013-0255] Appointments to Performance Review Boards for Senior... for Senior Executive Service. SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has announced the... and awarding authorities on performance appraisal ratings and performance awards for Senior Executives...

Actinide targets for fundamental research in nuclear physics

NASA Astrophysics Data System (ADS)

Eberhardt, K.; Düllmann, Ch. E.; Haas, R.; Mokry, Ch.; Runke, J.; Thörle-Pospiech, P.; Trautmann, N.

2018-05-01

Thin actinide layers deposited on various substrates are widely used as calibration sources in nuclear spectroscopy. Other applications include fundamental research in nuclear chemistry and -physics, e.g., the chemical and physical properties of super-heavy elements (SHE, Z > 103) or nuclear reaction studies with heavy ions. For the design of future nuclear reactors like fast-fission reactors and accelerator-driven systems for transmutation of nuclear waste, precise data for neutron absorption as well as neutron-induced fission cross section data for 242Pu with neutrons of different energies are of particular importance, requiring suitable Pu-targets. Another application includes studies of nuclear transitions in 229Th harvested as α-decay recoil product from a thin layer of its 233U precursor. For this, a thin and very smooth layer of 233U is used. We report here on the production of actinide layers mostly obtained by Molecular Plating (MP). MP is currently the only fabrication method in cases where the desired actinide material is available only in very limited amounts or possesses a high specific activity. Here, deposition is performed from organic solution applying a current density of 1-2 mA/cm2. Under these conditions target thicknesses of 500-1000 μg/cm2 are possible applying a single deposition step with deposition yields approaching 100 %. For yield determination α-particle spectroscopy, γ-spectroscopy and Neutron Activation Analysis is routinely used. Layer homogeneity is checked with Radiographic Imaging. As an alternative technique to MP the production of thin lanthanide and actinide layers by the so-called "Drop on Demand"-technique applied e.g., in ink-jet printing is currently under investigation.

An ancillary method in urine cytology: Nucleolar/nuclear volume ratio for discrimination between benign and malignant urothelial cells.

PubMed

Tone, Kiyoshi; Kojima, Keiko; Hoshiai, Keita; Kumagai, Naoya; Kijima, Hiroshi; Kurose, Akira

2016-06-01

The essential of urine cytology for the diagnosis and the follow-up of urothelial neoplasia has been widely recognized. However, there are some cases in which a definitive diagnosis cannot be made due to difficulty in discriminating between benign and malignant. This study evaluated the practicality of nucleolar/nuclear volume ratio (%) for the discrimination. Using Papanicolaou-stained slides, 253 benign urothelial cells and 282 malignant urothelial cells were selected and divided into a benign urothelial cell and an urothelial carcinoma (UC) cell groups. Three suspicious cases and four cases in which discrimination between benign and malignant was difficult were prepared for verification test. Subject cells were decolorized and stained with 4',6-diamidino-2-phenylindole for detection of the nuclei and the nucleoli. Z-stack method was performed to analyze. When the cutoff point of 1.514% discriminating benign urothelial cells and UC cells from nucleolar/nuclear volume ratio (%) was utilized, the sensitivity was 56.0%, the specificity was 88.5%, the positive predictive value was 84.5%, and the negative predictive value was 64.4%. Nuclear and nucleolar volume, number of the nucleoli, and nucleolar/nuclear volume ratio (%) were significantly higher in the UC cell group than in the benign urothelial cell group (P <0.001). In the verification test using the nucleolar/nuclear ratio (%), four of the seven cases were concordant with the final diagnosis. This study analyzed the nuclear and nucleolar volume to establish an index for discrimination of benign and malignant urothelial cells, providing possible additional information in urine cytology. Diagn. Cytopathol. 2016;44:483-491. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Nuclear proliferomics: A new field of study to identify signatures of nuclear materials as demonstrated on alpha-UO3.

PubMed

Schwerdt, Ian J; Brenkmann, Alexandria; Martinson, Sean; Albrecht, Brent D; Heffernan, Sean; Klosterman, Michael R; Kirkham, Trenton; Tasdizen, Tolga; McDonald Iv, Luther W

2018-08-15

The use of a limited set of signatures in nuclear forensics and nuclear safeguards may reduce the discriminating power for identifying unknown nuclear materials, or for verifying processing at existing facilities. Nuclear proliferomics is a proposed new field of study that advocates for the acquisition of large databases of nuclear material properties from a variety of analytical techniques. As demonstrated on a common uranium trioxide polymorph, α-UO 3 , in this paper, nuclear proliferomics increases the ability to improve confidence in identifying the processing history of nuclear materials. Specifically, α-UO 3 was investigated from the calcination of unwashed uranyl peroxide at 350, 400, 450, 500, and 550 °C in air. Scanning electron microscopy (SEM) images were acquired of the surface morphology, and distinct qualitative differences are presented between unwashed and washed uranyl peroxide, as well as the calcination products from the unwashed uranyl peroxide at the investigated temperatures. Differential scanning calorimetry (DSC), UV-Vis spectrophotometry, powder X-ray diffraction (p-XRD), and thermogravimetric analysis-mass spectrometry (TGA-MS) were used to understand the source of these morphological differences as a function of calcination temperature. Additionally, the SEM images were manually segmented using Morphological Analysis for MAterials (MAMA) software to identify quantifiable differences in morphology for three different surface features present on the unwashed uranyl peroxide calcination products. No single quantifiable signature was sufficient to discern all calcination temperatures with a high degree of confidence; therefore, advanced statistical analysis was performed to allow the combination of a number of quantitative signatures, with their associated uncertainties, to allow for complete discernment by calcination history. Furthermore, machine learning was applied to the acquired SEM images to demonstrate automated discernment with at least 89% accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

NASA Technical Reports Server (NTRS)

Emrich, William J. Jr.; Moran, Robert P.; Pearson, J. Boise

2012-01-01

To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities

α-Amanitin-Resistant Viral RNA Synthesis in Nuclei Isolated from Nuclear Polyhedrosis Virus-Infected Heliothis zea Larvae and Spodoptera frugiperda Cells

PubMed Central

Grula, Marjori A.; Buller, Patricia L.; Weaver, Robert F.

1981-01-01

[3H]RNA was synthesized in nuclei isolated at various times postinfection from the fat bodies of Heliothis zea larvae infected with H. zea nuclear polyhedrosis virus and from cultured Spodoptera frugiperda cells infected with Autographa californica nuclear polyhedrosis virus. To detect virus-specific RNA synthesis, the [3H]RNA was hybridized to denatured viral DNA immobilized on nitrocellulose filters. Nuclear polyhedrosis virus-specific RNA synthesis in the infected nuclei isolated from H. zea larval fat bodies and S. frugiperda cells was only inhibited 20 to 25% by concentrations of α-amanitin sufficient to inhibit the host RNA polymerase II. In addition, a productive nuclear polyhedrosis virus infection was obtained in S. frugiperda cells grown in the presence of an α-amanitin concentration that inhibited 90% of the cellular RNA polymerase II activity. The cellular RNA polymerase II enzyme remained sensitive to α-amanitin during infection, and there was no evidence that a virus-coded, α-amanitin-resistant enzyme was synthesized after the onset of infection. The data suggest that the bulk of nuclear polyhedrosis virus-specific RNA synthesis in isolated nuclei is transcribed by an enzyme other than the host RNA polymerase II. PMID:16789208

A Muon Tomography Station with GEM Detectors for Nuclear Threat Detection

NASA Astrophysics Data System (ADS)

Staib, Michael; Gnanvo, Kondo; Grasso, Leonard; Hohlmann, Marcus; Locke, Judson; Costa, Filippo; Martoiu, Sorin; Muller, Hans

2011-10-01

Muon tomography for homeland security aims at detecting well-shielded nuclear contraband in cargo and imaging it in 3D. The technique exploits multiple scattering of atmospheric cosmic ray muons, which is stronger in dense, high-Z nuclear materials, e.g. enriched uranium, than in low-Z and medium-Z shielding materials. We have constructed and operated a compact Muon Tomography Station (MTS) that tracks muons with six to ten 30 cm x 30 cm Triple Gas Electron Multiplier (GEM) detectors placed on the sides of a 27-liter cubic imaging volume. The 2D strip readouts of the GEMs achieve a spatial resolution of ˜130 μm in both dimensions and the station is operated at a muon trigger rate of ˜20 Hz. The 1,536 strips per GEM detector are read out with the first medium-size implementation of the Scalable Readout System (SRS) developed specifically for Micro-Pattern Gas Detectors by the RD51 collaboration at CERN. We discuss the performance of this MTS prototype and present experimental results on tomographic imaging of high-Z objects with and without shielding.

Nuclear education in public health and nursing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winder, A.E.; Stanitis, M.A.

Twenty-three public health schools and 492 university schools of nursing were surveyed to gather specific information on educational programs related to nuclear war. Twenty public health schools and 240 nursing schools responded. Nuclear war-related content was most likely to appear in disaster nursing and in environmental health courses. Three schools of public health report that they currently offer elective courses on nuclear war. Innovative curricula included political action projects for nuclear war prevention.

Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruce G. Schnitzler; Stanley K. Borowski

2010-07-01

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effortmore » was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature profiles in the engines. Engine performance can be improved by some combination of propellant flow control at the fuel element level and by varying the fuel composition. Enrichment zoning at the fuel element level with lower enrichments in the higher power elements at the core center and on the core periphery is particularly effective. Power flattening by enrichment zoning typically results in more uniform propellant exit temperatures and improved engine performance. For the SNRE, element enrichment zoning provided very flat radial power profiles with 551 of the 564 fuel elements within 1% of the average element power. Results for this and alternate enrichment zoning options for the SNRE are compared.« less

The Role of Ect2 Nuclear RhoGEF Activity in Ovarian Cancer Cell Transformation

PubMed Central

Huff, Lauren P.; DeCristo, Molly J.; Trembath, Dimitri; Kuan, Pei Fen; Yim, Margaret; Liu, Jinsong; Cook, Danielle R.; Miller, C. Ryan; Der, Channing J.

2013-01-01

Ect2, a Rho guanine nucleotide exchange factor (RhoGEF), is atypical among RhoGEFs in its predominantly nuclear localization in interphase cells. One current model suggests that Ect2 mislocalization drives cellular transformation by promoting aberrant activation of cytoplasmic Rho family GTPase substrates. However, in ovarian cancers, where Ect2 is both amplified and overexpressed at the mRNA level, we observed that the protein is highly expressed and predominantly nuclear and that nuclear but not cytoplasmic Ect2 increases with advanced disease. Knockdown of Ect2 in ovarian cancer cell lines impaired their anchorage-independent growth without affecting their growth on plastic. Restoration of Ect2 expression rescued the anchorage-independent growth defect, but not if either the DH catalytic domain or the nuclear localization sequences of Ect2 were mutated. These results suggested a novel mechanism whereby Ect2 could drive transformation in ovarian cancer cells by acting as a RhoGEF specifically within the nucleus. Interestingly, Ect2 had an intrinsically distinct GTPase specificity profile in the nucleus versus the cytoplasm. Nuclear Ect2 bound preferentially to Rac1, while cytoplasmic Ect2 bound to RhoA but not Rac. Consistent with nuclear activation of endogenous Rac, Ect2 overexpression was sufficient to recruit Rac effectors to the nucleus, a process that required a functional Ect2 catalytic domain. Furthermore, expression of active nuclearly targeted Rac1 rescued the defect in transformed growth caused by Ect2 knockdown. Our work suggests a novel mechanism of Ect2-driven transformation, identifies subcellular localization as a regulator of GEF specificity, and implicates activation of nuclear Rac1 in cellular transformation. PMID:24386507

Used Nuclear Fuel Loading and Structural Performance Under Normal Conditions of Transport- Demonstration of Approach and Results on Used Fuel Performance Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adkins, Harold; Geelhood, Ken; Koeppel, Brian

2013-09-30

This document addresses Oak Ridge National Laboratory milestone M2FT-13OR0822015 Demonstration of Approach and Results on Used Nuclear Fuel Performance Characterization. This report provides results of the initial demonstration of the modeling capability developed to perform preliminary deterministic evaluations of moderate-to-high burnup used nuclear fuel (UNF) mechanical performance under normal conditions of storage (NCS) and normal conditions of transport (NCT) conditions. This report also provides results from the sensitivity studies that have been performed. Finally, discussion on the long-term goals and objectives of this initiative are provided.

Fabrication and Testing of CERMET Fuel Materials for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Hickman, Robert; Broadway, Jeramie; Mireles, Omar

2012-01-01

A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on Nuclear Thermal Propulsion (NTP) is currently being developed for Advanced Space Exploration Systems. The overall goal of the project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of NTP systems. The current technology roadmap for NTP identifies the development of a robust fuel form as a critical near term need. The lack of a qualified nuclear fuel is a significant technical risk that will require a considerable fraction of program resources to mitigate. Due to these risks and the cost for qualification, the development and selection of a primary fuel must begin prior to Authority to Proceed (ATP) for a specific mission. The fuel development is a progressive approach to incrementally reduce risk, converge the fuel materials, and mature the design and fabrication process of the fuel element. A key objective of the current project is to advance the maturity of CERMET fuels. The work includes fuel processing development and characterization, fuel specimen hot hydrogen screening, and prototypic fuel element testing. Early fuel materials development is critical to help validate requirements and fuel performance. The purpose of this paper is to provide an overview and status of the work at Marshall Space Flight Center (MSFC).

Sheep: The First Large Animal Model in Nuclear Transfer Research

PubMed Central

Czernik, Marta; Zacchini, Federica; Iuso, Domenico; Scapolo, Pier Augusto

2013-01-01

Abstract The scope of this article is not to provide an exhaustive review of nuclear transfer research, because many authoritative reviews exist on the biological issues related to somatic and embryonic cell nuclear transfer. We shall instead provide an overview on the work done specifically on sheep and the value of this work on the greater nuclear transfer landscape. PMID:24033140

REVIEW OF MECHANISTIC UNDERSTANDING AND MODELING AND UNCERTAINTY ANALYSIS METHODS FOR PREDICTING CEMENTITIOUS BARRIER PERFORMANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langton, C.; Kosson, D.

2009-11-30

Cementitious barriers for nuclear applications are one of the primary controls for preventing or limiting radionuclide release into the environment. At the present time, performance and risk assessments do not fully incorporate the effectiveness of engineered barriers because the processes that influence performance are coupled and complicated. Better understanding the behavior of cementitious barriers is necessary to evaluate and improve the design of materials and structures used for radioactive waste containment, life extension of current nuclear facilities, and design of future nuclear facilities, including those needed for nuclear fuel storage and processing, nuclear power production and waste management. The focusmore » of the Cementitious Barriers Partnership (CBP) literature review is to document the current level of knowledge with respect to: (1) mechanisms and processes that directly influence the performance of cementitious materials (2) methodologies for modeling the performance of these mechanisms and processes and (3) approaches to addressing and quantifying uncertainties associated with performance predictions. This will serve as an important reference document for the professional community responsible for the design and performance assessment of cementitious materials in nuclear applications. This review also provides a multi-disciplinary foundation for identification, research, development and demonstration of improvements in conceptual understanding, measurements and performance modeling that would be lead to significant reductions in the uncertainties and improved confidence in the estimating the long-term performance of cementitious materials in nuclear applications. This report identifies: (1) technology gaps that may be filled by the CBP project and also (2) information and computational methods that are in currently being applied in related fields but have not yet been incorporated into performance assessments of cementitious barriers. The various chapters contain both a description of the mechanism or and a discussion of the current approaches to modeling the phenomena.« less

Nuclear-safety institution in France: emergence and development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vallet, B.M.

1986-01-01

This research work examines the social construction of the nuclear-safety institution in France, and the concurrent increased focus on the nuclear-risk issue. Emphasis on risk and safety, as primarily technical issues, can partly be seen as a strategy. Employed by power elites in the nuclear technostructure, this diverts emphasis away from controversial and normative questions regarding the political and social consequences of technology to questions of technology that appear to be absolute to the technology itself. Nuclear safety, which started from a preoccupation with risk related to the nuclear energy research and development process, is examined using the analytic conceptmore » of field. As a social arena patterned to achieve specific tasks, this field is dominated by a body of state engineers recognized to have high-level scientific and administrative competences. It is structured by procedures and administrative hierarchies as well as by technical rules, norms, and standards. These are formalized and rationalized through technical, economic, political, and social needs; over time; they consolidate the field into an institution. The study documents the nuclear-safety institution as an integral part of the nuclear technostructure, which has historically used the specificity of its expertise as a buffer against outside interference.« less

Studies of Heavy-Ion Reactions and Transuranic Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, W. Udo

2016-07-28

Studies of heavy-ion reactions and transuranic nuclei performed by the University of Rochester Nuclear Science Research Group have been successful in furthering experimental systematics and theoretical understanding of the behavior of nuclear systems excited to their limits of stability. The theoretical results explain specifically the “boiling” and “vaporization” of atomic nuclei, but are more generally applicable to isolated, quantal many-particle systems which, under thermal or mechanical stresses, all disintegrate by evaporation, via surface cluster emission, or via fission-like processes. Accompanying experimental investigations by the group have demonstrated several new types of dynamical instability of nuclei: In central, “head-on” collisions, targetmore » nuclei exhibit limited ability to stop energetic projectile nuclei and to dissipate the imparted linear momentum. Substantial matter overlap (“neck”) between projectile and target nuclei, which is observed at elevated collision energies, can be stretched considerably and break at several places simultaneously. These results provide new testing grounds for microscopic theory of the cohesion of nuclear matter. This property has remained elusive, even though the elementary nucleon-nucleon forces are well known since some time. Technical R&D has resulted in a detailed characterization of a novel plastic material, which can now be used in the design of sensitive diagnostic systems for various types of radio-activity. Innovative application of powerful laser systems has produced intense, controllable sources of exotic particle radioactivity for nuclear investigations. Several students have received their Ph.D. degree in experimental nuclear science for their work on basic nuclear research or R&D projects.« less

A Discrepancy-Based Methodology for Nuclear Training Program Evaluation.

ERIC Educational Resources Information Center

Cantor, Jeffrey A.

1991-01-01

A three-phase comprehensive process for commercial nuclear power training program evaluation is presented. The discrepancy-based methodology was developed after the Three Mile Island nuclear reactor accident. It facilitates analysis of program components to identify discrepancies among program specifications, actual outcomes, and industry…

Fine control of nuclear confinement identifies a threshold deformation leading to lamina rupture and induction of specific genes.

PubMed

Le Berre, Maël; Aubertin, Johannes; Piel, Matthieu

2012-11-01

The quest to understand how the mechanical and geometrical environment of cells impacts their behavior and fate has been a major force driving the recent development of new technologies in cell biology research. Despite rapid advances in this field, many challenges remain in order to bridge the gap between the classical and simple cell culture plate and the biological reality of actual tissue. In tissues, cells have their physical space constrained by neighboring cells and the extracellular matrix. Here, we propose a simple and versatile device to precisely and dynamically control this confinement parameter in cultured cells. We show that there is a precise threshold deformation above which the nuclear lamina breaks and reconstructs, whereas nuclear volume changes. We also show that different nuclear deformations correlate with the expression of specific sets of genes, including nuclear factors and classical mechanotransduction pathways. This versatile device thus enables the precise control of cell and nuclear deformation by confinement and the correlative study of the associated molecular events.

Innovations for In-Pile Measurements in the Framework of the CEA-SCK•CEN Joint Instrumentation Laboratory

NASA Astrophysics Data System (ADS)

Villard, Jean-Francois; Schyns, Marc

2010-12-01

Optimizing the life cycle of nuclear systems under safety constraints requires high-performance experimental programs to reduce uncertainties on margins and limits. In addition to improvement in modeling and simulation, innovation in instrumentation is crucial for analytical and integral experiments conducted in research reactors. The quality of nuclear research programs relies obviously on an excellent knowledge of their experimental environment which constantly calls for better online determination of neutron and gamma flux. But the combination of continuously increasing scientific requirements and new experimental domains -brought for example by Generation IV programsnecessitates also major innovations for in-pile measurements of temperature, dimensions, pressure or chemical analysis in innovative mediums. At the same time, the recent arising of a European platform around the building of the Jules Horowitz Reactor offers new opportunities for research institutes and organizations to pool their resources in order to face these technical challenges. In this situation, CEA (French Nuclear Energy Commission) and SCK'CEN (Belgian Nuclear Research Centre) have combined their efforts and now share common developments through a Joint Instrumentation Laboratory. Significant progresses have thus been obtained recently in the field of in-pile measurements, on one hand by improvement of existing measurement methods, and on the other hand by introduction in research reactors of original measurement techniques. This paper highlights the state-of-the-art and the main requirements regarding in-pile measurements, particularly for the needs of current and future irradiation programs performed in material testing reactors. Some of the main on-going developments performed in the framework of the Joint Instrumentation Laboratory are also described, such as: - a unique fast neutron flux measurement system using fission chambers with 242Pu deposit and a specific online data processing, - an optical system designed to perform in-pile dimensional measurements of material samples under irradiation, - an acoustical instrumentation allowing the online characterization of fission gas release in Pressurized Water Reactor fuel rods. For each example, the obtained results, expected impacts and development status are detailed.

Selective ligand activity at Nur/retinoid X receptor complexes revealed by dimer-specific bioluminescence resonance energy transfer-based sensors

PubMed Central

Giner, Xavier C; Cotnoir-White, David; Mader, Sylvie; Lévesque, Daniel

2017-01-01

Retinoid X receptors (RXR) play a role as master regulators due to their capacity to form heterodimers with other nuclear receptors. Accordingly, retinoid signaling is involved in multiple biological processes, including development, cell differentiation, metabolism and cell death. However, the role and functions of RXR in different heterodimer complexes remain unsolved, mainly because most RXR drugs (called rexinoids) are not selective to specific heterodimer complexes. This also strongly limits the use of rexinoids for specific therapeutic approaches. In order to better characterize rexinoids at specific nuclear receptor complexes, we have developed and optimized luciferase protein complementation-based Bioluminescence Resonance Energy Transfer (BRET) assays, which can directly measure recruitment of a co-activator motif fused to yellow fluorescent protein (YFP) by specific nuclear receptor dimers. To validate the assays, we compared rexinoid modulation of co-activator recruitment by RXR homodimer, and heterodimers Nur77/RXR and Nurr1/RXR. Results reveal that some rexinoids display selective co-activator recruitment activities with homo- or hetero-dimer complexes. In particular, SR11237 (BMS649) has increased potency for recruitment of co-activator motif and transcriptional activity with the Nur77/RXR heterodimer compared to other complexes. This technology should prove useful to identify new compounds with specificity for individual dimeric species formed by nuclear receptors. PMID:26148973

Fabrication, characterization, and irradiation of an austenitic oxide dispersion strengthened steel suited for next generation nuclear applications

NASA Astrophysics Data System (ADS)

Brooks, Adam J.

As nuclear energy systems become more advanced, the materials encompassing them need to perform at higher temperatures for longer periods of time. In this Master's thesis we experiment with an oxide dispersion strengthened (ODS) austenitic steel that has been recently developed. ODS materials have a small concentration of nano oxide particles dispersed in their matrix, and typically have higher strength and better extreme temperature creep resistance characteristics than ordinary steels. However, no ODS materials have ever been installed in a commercial power reactor to date. Being a newer research material, there are many unanswered phenomena that need to be addressed regarding the performance under irradiation. Furthermore, due to the ODS material traditionally needing to follow a powder metallurgy fabrication route, there are many processing parameters that need to be optimized before achieving a nuclear grade material specification. In this Master's thesis we explore the development of a novel ODS processing technology conducted in Beijing, China, to produce solutionized bulk ODS samples with 97% theoretical density. This is done using relatively low temperatures and ultra high pressure (UHP) equipment, to compact the mechanically alloyed (MA) steel powder into bulk samples without any thermal phase change influence or oxide precipitation. By having solutionized bulk ODS samples, transmission electron microscopy (TEM) observation of nano oxide precipitation within the steel material can be studied by applying post heat treatments. These types of samples will be very useful to the science and engineering community, to answer questions regarding material powder compacting, oxide synthesis, and performance. Subsequent analysis performed at Queen's University included X-ray diffraction (XRD) and inductively coupled plasma optical emission spectrometry (ICP-OES). Additional TEM in-situ 1MeV Kr2+ irradiation experiments coupled with energy dispersive X-ray (EDX) techniques, were also performed on large (200nm+) non-stoichiometric oxides embedded within the austenite steel grains, in an attempt to quantify the elemental compositional changes during high temperature (520°C) heavy ion irradiation.

Prenatal exposure of mice to diethylstilbestrol disrupts T-cell differentiation by regulating Fas/Fas ligand expression through estrogen receptor element and nuclear factor-κB motifs.

PubMed

Singh, Narendra P; Singh, Udai P; Nagarkatti, Prakash S; Nagarkatti, Mitzi

2012-11-01

Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effect of prenatal exposure to DES on thymocyte differentiation involving apoptotic pathways. Prenatal DES exposure caused thymic atrophy, apoptosis, and up-regulation of Fas and Fas ligand (FasL) expression in thymocytes. To examine the mechanism underlying DES-mediated regulation of Fas and FasL, we performed luciferase assays using T cells transfected with luciferase reporter constructs containing full-length Fas or FasL promoters. There was significant luciferase induction in the presence of Fas or FasL promoters after DES exposure. Further analysis demonstrated the presence of several cis-regulatory motifs on both Fas and FasL promoters. When DES-induced transcription factors were analyzed, estrogen receptor element (ERE), nuclear factor κB (NF-κB), nuclear factor of activated T cells (NF-AT), and activator protein-1 motifs on the Fas promoter, as well as ERE, NF-κB, and NF-AT motifs on the FasL promoter, showed binding affinity with the transcription factors. Electrophoretic mobility-shift assays were performed to verify the binding affinity of cis-regulatory motifs of Fas or FasL promoters with transcription factors. There was shift in mobility of probes (ERE or NF-κB2) of both Fas and FasL in the presence of nuclear proteins from DES-treated cells, and the shift was specific to DES because these probes failed to shift their mobility in the presence of nuclear proteins from vehicle-treated cells. Together, the current study demonstrates that prenatal exposure to DES triggers significant alterations in apoptotic molecules expressed on thymocytes, which may affect T-cell differentiation and cause long-term effects on the immune functions.

Prenatal Exposure of Mice to Diethylstilbestrol Disrupts T-Cell Differentiation by Regulating Fas/Fas Ligand Expression through Estrogen Receptor Element and Nuclear Factor-κB Motifs

PubMed Central

Singh, Narendra P.; Singh, Udai P.; Nagarkatti, Prakash S.

2012-01-01

Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effect of prenatal exposure to DES on thymocyte differentiation involving apoptotic pathways. Prenatal DES exposure caused thymic atrophy, apoptosis, and up-regulation of Fas and Fas ligand (FasL) expression in thymocytes. To examine the mechanism underlying DES-mediated regulation of Fas and FasL, we performed luciferase assays using T cells transfected with luciferase reporter constructs containing full-length Fas or FasL promoters. There was significant luciferase induction in the presence of Fas or FasL promoters after DES exposure. Further analysis demonstrated the presence of several cis-regulatory motifs on both Fas and FasL promoters. When DES-induced transcription factors were analyzed, estrogen receptor element (ERE), nuclear factor κB (NF-κB), nuclear factor of activated T cells (NF-AT), and activator protein-1 motifs on the Fas promoter, as well as ERE, NF-κB, and NF-AT motifs on the FasL promoter, showed binding affinity with the transcription factors. Electrophoretic mobility-shift assays were performed to verify the binding affinity of cis-regulatory motifs of Fas or FasL promoters with transcription factors. There was shift in mobility of probes (ERE or NF-κB2) of both Fas and FasL in the presence of nuclear proteins from DES-treated cells, and the shift was specific to DES because these probes failed to shift their mobility in the presence of nuclear proteins from vehicle-treated cells. Together, the current study demonstrates that prenatal exposure to DES triggers significant alterations in apoptotic molecules expressed on thymocytes, which may affect T-cell differentiation and cause long-term effects on the immune functions. PMID:22888145

Nuclear education in public health and nursing.

PubMed Central

Winder, A E; Stanitis, M A

1988-01-01

Twenty-three public health schools and 492 university schools of nursing were surveyed to gather specific information on educational programs related to nuclear war. Twenty public health schools and 240 nursing schools responded. Nuclear war-related content was most likely to appear in disaster nursing and in environmental health courses. Three schools of public health report that they currently offer elective courses on nuclear war. Innovative curricula included political action projects for nuclear war prevention. PMID:3389435

Nucleocytoplasmic Transport of RNAs and RNA-Protein Complexes.

PubMed

Sloan, Katherine E; Gleizes, Pierre-Emmanuel; Bohnsack, Markus T

2016-05-22

RNAs and ribonucleoprotein complexes (RNPs) play key roles in mediating and regulating gene expression. In eukaryotes, most RNAs are transcribed, processed and assembled with proteins in the nucleus and then either function in the cytoplasm or also undergo a cytoplasmic phase in their biogenesis. This compartmentalization ensures that sequential steps in gene expression and RNP production are performed in the correct order and it allows important quality control mechanisms that prevent the involvement of aberrant RNAs/RNPs in these cellular pathways. The selective exchange of RNAs/RNPs between the nucleus and cytoplasm is enabled by nuclear pore complexes, which function as gateways between these compartments. RNA/RNP transport is facilitated by a range of nuclear transport receptors and adaptors, which are specifically recruited to their cargos and mediate interactions with nucleoporins to allow directional translocation through nuclear pore complexes. While some transport factors are only responsible for the export/import of a certain class of RNA/RNP, others are multifunctional and, in the case of large RNPs, several export factors appear to work together to bring about export. Recent structural studies have revealed aspects of the mechanisms employed by transport receptors to enable specific cargo recognition, and genome-wide approaches have provided the first insights into the diverse composition of pre-mRNPs during export. Furthermore, the regulation of RNA/RNP export is emerging as an important means to modulate gene expression under stress conditions and in disease. Copyright © 2015. Published by Elsevier Ltd.

Computational nuclear quantum many-body problem: The UNEDF project

NASA Astrophysics Data System (ADS)

Bogner, S.; Bulgac, A.; Carlson, J.; Engel, J.; Fann, G.; Furnstahl, R. J.; Gandolfi, S.; Hagen, G.; Horoi, M.; Johnson, C.; Kortelainen, M.; Lusk, E.; Maris, P.; Nam, H.; Navratil, P.; Nazarewicz, W.; Ng, E.; Nobre, G. P. A.; Ormand, E.; Papenbrock, T.; Pei, J.; Pieper, S. C.; Quaglioni, S.; Roche, K. J.; Sarich, J.; Schunck, N.; Sosonkina, M.; Terasaki, J.; Thompson, I.; Vary, J. P.; Wild, S. M.

2013-10-01

The UNEDF project was a large-scale collaborative effort that applied high-performance computing to the nuclear quantum many-body problem. The primary focus of the project was on constructing, validating, and applying an optimized nuclear energy density functional, which entailed a wide range of pioneering developments in microscopic nuclear structure and reactions, algorithms, high-performance computing, and uncertainty quantification. UNEDF demonstrated that close associations among nuclear physicists, mathematicians, and computer scientists can lead to novel physics outcomes built on algorithmic innovations and computational developments. This review showcases a wide range of UNEDF science results to illustrate this interplay.

The nuclear higher-order structure defined by the set of topological relationships between DNA and the nuclear matrix is species-specific in hepatocytes.

PubMed

Silva-Santiago, Evangelina; Pardo, Juan Pablo; Hernández-Muñoz, Rolando; Aranda-Anzaldo, Armando

2017-01-15

During the interphase the nuclear DNA of metazoan cells is organized in supercoiled loops anchored to constituents of a nuclear substructure or compartment known as the nuclear matrix. The stable interactions between DNA and the nuclear matrix (NM) correspond to a set of topological relationships that define a nuclear higher-order structure (NHOS). Current evidence suggests that the NHOS is cell-type-specific. Biophysical evidence and theoretical models suggest that thermodynamic and structural constraints drive the actualization of DNA-NM interactions. However, if the topological relationships between DNA and the NM were the subject of any biological constraint with functional significance then they must be adaptive and thus be positively selected by natural selection and they should be reasonably conserved, at least within closely related species. We carried out a coarse-grained, comparative evaluation of the DNA-NM topological relationships in primary hepatocytes from two closely related mammals: rat and mouse, by determining the relative position to the NM of a limited set of target sequences corresponding to highly-conserved genomic regions that also represent a sample of distinct chromosome territories within the interphase nucleus. Our results indicate that the pattern of topological relationships between DNA and the NM is not conserved between the hepatocytes of the two closely related species, suggesting that the NHOS, like the karyotype, is species-specific. Copyright © 2016 Elsevier B.V. All rights reserved.

A New Program to Teach Nuclear and Radiochemistry to Undergraduates.

ERIC Educational Resources Information Center

Catchen, Gary L.; Canelos, James

1988-01-01

Follows the development of a course in nuclear and radiochemistry at Penn State. Lists specific nuclear science topics covered in the undergraduate level course. Describes audio-visual materials that have been developed for the course and includes a survey of students taking the course. (ML)

A rhomboid gene controls speciation through regulation of nuclear-mitochondrial compatibility in Triticum

USDA-ARS?s Scientific Manuscript database

The nuclear encoded species cytoplasm specific (scs) genes control nuclear-cytoplasmic compatibility in Triticum. Alloplasmic cells, which have nucleus and cytoplasm derived from different species, produce vigorous and vital organisms only when the correct version of scs is present in their nucleus....

10 CFR 50.36 - Technical specifications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... nuclear reactors are limits upon important process variables that are found to be necessary to reasonably... Commission terminates the license for the reactor, except for nuclear power reactors licensed under § 50.21(b... for nuclear reactors are settings for automatic protective devices related to those variables having...

10 CFR 50.36 - Technical specifications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... nuclear reactors are limits upon important process variables that are found to be necessary to reasonably... Commission terminates the license for the reactor, except for nuclear power reactors licensed under § 50.21(b... for nuclear reactors are settings for automatic protective devices related to those variables having...

10 CFR 50.36 - Technical specifications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... nuclear reactors are limits upon important process variables that are found to be necessary to reasonably... Commission terminates the license for the reactor, except for nuclear power reactors licensed under § 50.21(b... for nuclear reactors are settings for automatic protective devices related to those variables having...

Learning to Embrace Nuclear Physics through Education

NASA Astrophysics Data System (ADS)

Avadanei, Camelia

2010-01-01

Due to its achievements, nuclear physics is more and more present in life of every member of the society. Its applications in the medical field and in nuclear energy, as well as the advanced research, always pushing the limits of science towards micro cosmos and macro cosmos, are subjects frequently presented in the media. In addition to their invaluable benefits, these achievements involve also particular rules to prevent potential risks. These risks are also underlined by the media, often being presented in an unfriendly manner. Specialists in nuclear physics are familiar with these problems complying with the specific rules in order to reduce risks at insignificant levels. The development of a specific field ("Radiation protection") defining norms and requirements for "assuring the radiological safety of the workers, population and environment," and its dynamics represent a proof of a responsible attitude regarding nuclear safety. Dedicated international bodies and experts analyze and rigorously evaluate risks in order to draw the right ways of managing activity in the field. The improvement of the formal and informal education of public regarding the real risks of nuclear applications is very important in order to understand and better assimilate some general rules concerning the use of these techniques, as well as for their correct perception, leading to an increase of interest towards nuclear physics. This educational update can be started even from elementary school and continued in each stage of formal education in adapted forms. The task of informing general public is to be carried out mainly by specialists who, unlike 30-40 years ago, can rely on a much more efficient generation of communications' mean. Taking into account the lack of interest for nuclear, an attractive way of presenting the achievements and future possibilities of nuclear physics would contribute to youth orientation towards specific universities in order to become next generation of specialists in the field. Facing new challenges, society becomes aware of the fact that education represents the real solution to escalade them. Nuclear physics plays an important role in ensuring energetic resources for the near future and in reducing greenhouse effects. On the other hand, especially nuclear physics will permit to solve the enigma of universe birth. As in any other field, development involves continuous education and knowledge upgrading for all categories carrying out nuclear activities. For radiation protection workers and specialists, periodically refreshment courses are mandatory, in compliance with the national and international specific requirements.

78 FR 55244 - Senior Executive Service Performance Review Board; Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-10

... DEFENSE NUCLEAR FACILITIES SAFETY BOARD Senior Executive Service Performance Review Board... the membership of the Defense Nuclear Facilities Safety Board (DNFSB) Senior Executive Service (SES... rating of a senior executive's performance, the executive's response, and the higher level official's...

RELAP5-3D Resolution of Known Restart/Backup Issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mesina, George L.; Anderson, Nolan A.

2014-12-01

The state-of-the-art nuclear reactor system safety analysis computer program developed at the Idaho National Laboratory (INL), RELAP5-3D, continues to adapt to changes in computer hardware and software and to develop to meet the ever-expanding needs of the nuclear industry. To continue at the forefront, code testing must evolve with both code and industry developments, and it must work correctly. To best ensure this, the processes of Software Verification and Validation (V&V) are applied. Verification compares coding against its documented algorithms and equations and compares its calculations against analytical solutions and the method of manufactured solutions. A form of this, sequentialmore » verification, checks code specifications against coding only when originally written then applies regression testing which compares code calculations between consecutive updates or versions on a set of test cases to check that the performance does not change. A sequential verification testing system was specially constructed for RELAP5-3D to both detect errors with extreme accuracy and cover all nuclear-plant-relevant code features. Detection is provided through a “verification file” that records double precision sums of key variables. Coverage is provided by a test suite of input decks that exercise code features and capabilities necessary to model a nuclear power plant. A matrix of test features and short-running cases that exercise them is presented. This testing system is used to test base cases (called null testing) as well as restart and backup cases. It can test RELAP5-3D performance in both standalone and coupled (through PVM to other codes) runs. Application of verification testing revealed numerous restart and backup issues in both standalone and couple modes. This document reports the resolution of these issues.« less

Immunohistochemical analysis of S6K1 and S6K2 localization in human breast tumors.

PubMed

Filonenko, Valeriy V; Tytarenko, Ruslana; Azatjan, Sergey K; Savinska, Lilya O; Gaydar, Yuriy A; Gout, Ivan T; Usenko, Vasiliy S; Lyzogubov, Valeriy V

2004-12-01

To perform an immunohistochemical analysis of human breast adenomas and adenocarcinomas as well as normal breast tissues in respect of S6 ribosomal protein kinase (S6K) expression and localization in normal and transformed cells. The expression level and localization of S6K have been detected in formalin fixed, paraffin embedded sections of normal human breast tissues, adenomas and adenocarcinomas with different grade of differentiation. Immunohistochemical detection of S6K1 and S6K2 in normal human breast tissues and breast tumors were performed using specific monoclonal and polyclonal antibodies against S6K1 and S6K2 with following semiquantitative analysis. The increase of S6K content in the cytoplasm of epithelial cells in benign and malignant tumors has been detected. Nuclear accumulation of S6K1 and to a greater extend S6K2 have been found in breast adenocarcinomas. About 80% of breast adenocarcinomas cases revealed S6K2 nuclear staining comparing to normal tissues. In 31% of cases more then 50% of cancer cells had strong nuclear staining. Accumulation of S6K1 in the nucleus of neoplastic cells has been demonstrated in 25% of cases. Nuclear localization of S6K in the epithelial cells in normal breast tissues has not been detected. Immunohistochemical analysis of S6K1 and S6K2 expression in normal human breast tissues, benign and malignant breast tumors clearly indicates that both kinases are overexpressed in breast tumors. Semiquantitative analysis of peculiarities of S6K localization in normal tissues and tumors revealed that nucleoplasmic accumulation of S6K (especially S6K2) is a distinguishing feature of cancer cells.

Non-Nuclear Validation Test Results of a Closed Brayton Cycle Test-Loop

NASA Astrophysics Data System (ADS)

Wright, Steven A.

2007-01-01

Both NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, or for next generation nuclear power plants on earth. Although open Brayton cycles are in use for many applications (combined cycle power plants, aircraft engines), only a few closed Brayton cycles have been tested. Experience with closed Brayton cycles coupled to nuclear reactors is even more limited and current projections of Brayton cycle performance are based on analytic models. This report describes and compares experimental results with model predictions from a series of non-nuclear tests using a small scale closed loop Brayton cycle available at Sandia National Laboratories. A substantial amount of testing has been performed, and the information is being used to help validate models. In this report we summarize the results from three kinds of tests. These tests include: 1) test results that are useful for validating the characteristic flow curves of the turbomachinery for various gases ranging from ideal gases (Ar or Ar/He) to non-ideal gases such as CO2, 2) test results that represent shut down transients and decay heat removal capability of Brayton loops after reactor shut down, and 3) tests that map a range of operating power versus shaft speed curve and turbine inlet temperature that are useful for predicting stable operating conditions during both normal and off-normal operating behavior. These tests reveal significant interactions between the reactor and balance of plant. Specifically these results predict limited speed up behavior of the turbomachinery caused by loss of load, the conditions for stable operation, and for direct cooled reactors, the tests reveal that the coast down behavior during loss of power events can extend for hours provided the ultimate heat sink remains available.

High Fidelity Thermal Simulators for Non-Nuclear Testing: Analysis and Initial Results

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David

2007-01-01

Non-nuclear testing can be a valuable tool in the development of a space nuclear power system, providing system characterization data and allowing one to work through various fabrication, assembly and integration issues without the cost and time associated with a full ground nuclear test. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Testing with non-optimized heater elements allows one to assess thermal, heat transfer, and stress related attributes of a given system, but fails to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. High fidelity thermal simulators that match both the static and the dynamic fuel pin performance that would be observed in an operating, fueled nuclear reactor can vastly increase the value of non-nuclear test results. With optimized simulators, the integration of thermal hydraulic hardware tests with simulated neutronie response provides a bridge between electrically heated testing and fueled nuclear testing, providing a better assessment of system integration issues, characterization of integrated system response times and response characteristics, and assessment of potential design improvements' at a relatively small fiscal investment. Initial conceptual thermal simulator designs are determined by simple one-dimensional analysis at a single axial location and at steady state conditions; feasible concepts are then input into a detailed three-dimensional model for comparison to expected fuel pin performance. Static and dynamic fuel pin performance for a proposed reactor design is determined using SINDA/FLUINT thermal analysis software, and comparison is made between the expected nuclear performance and the performance of conceptual thermal simulator designs. Through a series of iterative analyses, a conceptual high fidelity design can developed. Test results presented in this paper correspond to a "first cut" simulator design for a potential liquid metal (NaK) cooled reactor design that could be applied for Lunar surface power. Proposed refinements to this simulator design are also presented.

The exosome component Rrp6 is required for RNA polymerase II termination at specific targets of the Nrd1-Nab3 pathway.

PubMed

Fox, Melanie J; Gao, Hongyu; Smith-Kinnaman, Whitney R; Liu, Yunlong; Mosley, Amber L

2015-01-01

The exosome and its nuclear specific subunit Rrp6 form a 3'-5' exonuclease complex that regulates diverse aspects of RNA biology including 3' end processing and degradation of a variety of noncoding RNAs (ncRNAs) and unstable transcripts. Known targets of the nuclear exosome include short (<1000 bp) RNAPII transcripts such as small noncoding RNAs (snRNAs), cryptic unstable transcripts (CUTs), and some stable unannotated transcripts (SUTs) that are terminated by an Nrd1, Nab3, and Sen1 (NNS) dependent mechanism. NNS-dependent termination is coupled to RNA 3' end processing and/or degradation by the Rrp6/exosome in yeast. Recent work suggests Nrd1 is necessary for transcriptome surveillance, regulating promoter directionality and suppressing antisense transcription independently of, or prior to, Rrp6 activity. It remains unclear whether Rrp6 is directly involved in termination; however, Rrp6 has been implicated in the 3' end processing and degradation of ncRNA transcripts including CUTs. To determine the role of Rrp6 in NNS termination globally, we performed RNA sequencing (RNA-Seq) on total RNA and perform ChIP-exo analysis of RNA Polymerase II (RNAPII) localization. Deletion of RRP6 promotes hyper-elongation of multiple NNS-dependent transcripts resulting from both improperly processed 3' RNA ends and faulty transcript termination at specific target genes. The defects in RNAPII termination cause transcriptome-wide changes in mRNA expression through transcription interference and/or antisense repression, similar to previously reported effects of depleting Nrd1 from the nucleus. Elongated transcripts were identified within all classes of known NNS targets with the largest changes in transcription termination occurring at CUTs. Interestingly, the extended transcripts that we have detected in our studies show remarkable similarity to Nrd1-unterminated transcripts at many locations, suggesting that Rrp6 acts with the NNS complex globally to promote transcription termination in addition to 3' end RNA processing and/or degradation at specific targets.

NASA Missions Enabled by Space Nuclear Systems

NASA Technical Reports Server (NTRS)

Scott, John H.; Schmidt, George R.

2009-01-01

This viewgraph presentation reviews NASA Space Missions that are enabled by Space Nuclear Systems. The topics include: 1) Space Nuclear System Applications; 2) Trade Space for Electric Power Systems; 3) Power Generation Specific Energy Trade Space; 4) Radioisotope Power Generation; 5) Radioisotope Missions; 6) Fission Power Generation; 7) Solar Powered Lunar Outpost; 8) Fission Powered Lunar Outpost; 9) Fission Electric Power Generation; and 10) Fission Nuclear Thermal Propulsion.

GKTC ACTIVITIES TO PROVIDE NUCLEAR MATERIAL PHYSICAL PROTECTION, CONTROL AND ACCOUNTING TRAINING FOR 2011-2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romanova, Olena; Gavrilyuk, Victor I.; Kirischuk, Volodymyr

2011-10-01

The GKTC was created at the Kyiv Institute of Nuclear Research as a result of collaborative efforts between the United States and Ukraine. The GKTC has been designated by the Ukrainian Government to provide the MPC&A training and methodological assistance to nuclear facilities and nuclear specialists. In 2010 the GKTC has conducted the planned assessment of training needs of Ukrainian MPC&A specialists. The objective of this work is to acquire the detailed information about the number of MPC&A specialists and guard personnel, who in the coming years should receive the further advanced training. As a result of the performed trainingmore » needs evaluation the GKTC has determined that in the coming years a number of new training courses need to be developed. Some training courses are already in the process of development. Also taking into account the specific of activity on the guarding of nuclear facilities, GKTC has begun to develop the specialized training courses for the guarding unit personnel. The evaluation of needs of training of Ukrainian specialists on the physical protection shows that without the technical base of learning is not possible to satisfy the needs of Ukrainian facilities, in particular, the need for further training of specialists who maintains physical protection technical means, provides vulnerability assessment and testing of technical means. To increase the training effectiveness and create the basis for specialized training courses holding the GKTC is now working on the construction of an Interior (non-classified) Physical Protection Training Site. The objective of this site is to simulate the actual conditions of the nuclear facility PP system including the complex of engineering and technical means that will help the GKTC training course participants to consolidate the knowledge and gain the practical skills in the work with PP system engineering and technical means for more effective performance of their official duties. This paper briefly describes the practical efforts applied to the provision of physical protection specialists advanced training in Ukraine and real results on the way to implement such efforts in 2011-2012.« less

Cost effective nuclear commercial grade dedication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maletz, J.J.; Marston, M.J.

1991-01-01

This paper describes a new computerized database method to create/edit/view specification technical data sheets (mini-specifications) for procurement of spare parts for nuclear facility maintenance and to develop information that could support possible future facility life extension efforts. This method may reduce cost when compared with current manual methods. The use of standardized technical data sheets (mini-specifications) for items of the same category improves efficiency. This method can be used for a variety of tasks, including: Nuclear safety-related procurement; Non-safety related procurement; Commercial grade item procurement/dedication; Evaluation of replacement items. This program will assist the nuclear facility in upgrading its procurementmore » activities consistent with the recent NUMARC Procurement Initiative. Proper utilization of the program will assist the user in assuring that the procured items are correct for the applications, provide data to assist in detecting fraudulent materials, minimize human error in withdrawing database information, improve data retrievability, improve traceability, and reduce long-term procurement costs.« less

Specific nuclear localizing sequence directs two myosin isoforms to the cell nucleus in calmodulin-sensitive manner.

PubMed

Dzijak, Rastislav; Yildirim, Sukriye; Kahle, Michal; Novák, Petr; Hnilicová, Jarmila; Venit, Tomáš; Hozák, Pavel

2012-01-01

Nuclear myosin I (NM1) was the first molecular motor identified in the cell nucleus. Together with nuclear actin, they participate in crucial nuclear events such as transcription, chromatin movements, and chromatin remodeling. NM1 is an isoform of myosin 1c (Myo1c) that was identified earlier and is known to act in the cytoplasm. NM1 differs from the "cytoplasmic" myosin 1c only by additional 16 amino acids at the N-terminus of the molecule. This amino acid stretch was therefore suggested to direct NM1 into the nucleus. We investigated the mechanism of nuclear import of NM1 in detail. Using over-expressed GFP chimeras encoding for truncated NM1 mutants, we identified a specific sequence that is necessary for its import to the nucleus. This novel nuclear localization sequence is placed within calmodulin-binding motif of NM1, thus it is present also in the Myo1c. We confirmed the presence of both isoforms in the nucleus by transfection of tagged NM1 and Myo1c constructs into cultured cells, and also by showing the presence of the endogenous Myo1c in purified nuclei of cells derived from knock-out mice lacking NM1. Using pull-down and co-immunoprecipitation assays we identified importin beta, importin 5 and importin 7 as nuclear transport receptors that bind NM1. Since the NLS sequence of NM1 lies within the region that also binds calmodulin we tested the influence of calmodulin on the localization of NM1. The presence of elevated levels of calmodulin interfered with nuclear localization of tagged NM1. We have shown that the novel specific NLS brings to the cell nucleus not only the "nuclear" isoform of myosin I (NM1 protein) but also its "cytoplasmic" isoform (Myo1c protein). This opens a new field for exploring functions of this molecular motor in nuclear processes, and for exploring the signals between cytoplasm and the nucleus.

SiRNA knockdown of the DEK nuclear protein mRNA enhances apoptosis and chemosensitivity of canine transitional cell carcinoma cells.

PubMed

Yamazaki, Hiroki; Iwano, Tomomi; Otsuka, Saori; Kagawa, Yumiko; Hoshino, Yuki; Hosoya, Kenji; Okumura, Masahiro; Takagi, Satoshi

2015-04-01

Transitional cell carcinoma (TCC) in dogs is an aggressive malignant neoplasm, originating in the epithelium of the urinary bladder. The DEK nuclear protein is overexpressed in several types of human bladder cancer, where it is involved in chromatin reconstruction, gene transcription and apoptosis. Since DEK represents a potential therapeutic target for canine TCC, this study was designed to investigate DEK expression in canine TCC and to determine the effects of DEK mRNA silencing on TCC cells in vitro. The gene expression profiles of seven selected cancer-associated genes was assessed in four canine TCC cell lines and expression of DEK protein was evaluated in bladder tissue biopsies from healthy dogs and those affected with cystitis or TCC. After transfection of four canine TCC cell lines with DEK-specific or scrambled siRNA, annexin V staining was performed to evaluate apoptosis, and methylthiazole tetrazolium assays were performed to assess both cell viability and sensitivity to carboplatin. DEK mRNA expression was relatively high in canine TCC cells and expression of the DEK protein was significantly greater in TCC tumours compared with the other tissue samples. After transfection with DEK-specific siRNA, apoptosis, cell growth inhibition, and enhanced sensitivity to carboplatin were observed in all TCC cells assessed. These research findings suggest that DEK could be a potential therapeutic target for canine TCC. Copyright © 2015 Elsevier Ltd. All rights reserved.

The role of PRA in the safety assessment of VVER Nuclear Power Plants in Ukraine.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kot, C.

1999-05-10

Ukraine operates thirteen (13) Soviet-designed pressurized water reactors, VVERS. All Ukrainian plants are currently operating with annually renewable permits until they update their safety analysis reports (SARs), in accordance with new SAR content requirements issued in September 1995, by the Nuclear Regulatory Authority and the Government Nuclear Power Coordinating Committee of Ukraine. The requirements are in three major areas: design basis accident (DBA) analysis, probabilistic risk assessment (PRA), and beyond design-basis accident (BDBA) analysis. The last two requirements, on PRA and BDBA, are new, and the DBA requirements are an expanded version of the older SAR requirements. The US Departmentmore » of Energy (USDOE), as part of its Soviet-Designed Reactor Safety activities, is providing assistance and technology transfer to Ukraine to support their nuclear power plants (NPPs) in developing a Western-type technical basis for the new SARs. USDOE sponsored In-Depth Safety Assessments (ISAs) are in progress at three pilot nuclear reactor units in Ukraine, South Ukraine Unit 1, Zaporizhzhya Unit 5, and Rivne Unit 1, and a follow-on study has been initiated at Khmenytskyy Unit 1. The ISA projects encompass most areas of plant safety evaluation, but the initial emphasis is on performing a detailed, plant-specific Level 1 Internal Events PRA. This allows the early definition of the plant risk profile, the identification of risk significant accident sequences and plant vulnerabilities and provides guidance for the remainder of the safety assessments.« less

Research on digital system design of nuclear power valve

NASA Astrophysics Data System (ADS)

Zhang, Xiaolong; Li, Yuan; Wang, Tao; Dai, Ye

2018-04-01

With the progress of China's nuclear power industry, nuclear power plant valve products is in a period of rapid development, high performance, low cost, short cycle of design requirements for nuclear power valve is proposed, so there is an urgent need for advanced digital design method and integrated design platform to provide technical support. Especially in the background of the nuclear power plant leakage in Japan, it is more practical to improve the design capability and product performance of the nuclear power valve. The finite element numerical analysis is a common and effective method for the development of nuclear power valves. Nuclear power valve has high safety, complexity of valve chamber and nonlinearity of seal joint surface. Therefore, it is urgent to establish accurate prediction models for earthquake prediction and seal failure to meet engineering accuracy and calculation conditions. In this paper, a general method of finite element modeling for nuclear power valve assembly and key components is presented, aiming at revealing the characteristics and rules of finite element modeling of nuclear power valves, and putting forward aprecision control strategy for finite element models for nuclear power valve characteristics analysis.

Defining the "proven technology" technical criterion in the reactor technology assessment for Malaysia's nuclear power program

NASA Astrophysics Data System (ADS)

Anuar, Nuraslinda; Kahar, Wan Shakirah Wan Abdul; Manan, Jamal Abdul Nasir Abd

2015-04-01

Developing countries that are considering the deployment of nuclear power plants (NPPs) in the near future need to perform reactor technology assessment (RTA) in order to select the most suitable reactor design. The International Atomic Energy Agency (IAEA) reported in the Common User Considerations (CUC) document that "proven technology" is one of the most important technical criteria for newcomer countries in performing the RTA. The qualitative description of five desired features for "proven technology" is relatively broad and only provides a general guideline to its characterization. This paper proposes a methodology to define the "proven technology" term according to a specific country's requirements using a three-stage evaluation process. The first evaluation stage screens the available technologies in the market against a predefined minimum Technology Readiness Level (TRL) derived as a condition based on national needs and policy objectives. The result is a list of technology options, which are then assessed in the second evaluation stage against quantitative definitions of CUC desired features for proven technology. The potential technology candidates produced from this evaluation is further narrowed down to obtain a list of proven technology candidates by assessing them against selected risk criteria and the established maximum allowable total score using a scoring matrix. The outcome of this methodology is the proven technology candidates selected using an accurate definition of "proven technology" that fulfills the policy objectives, national needs and risk, and country-specific CUC desired features of the country that performs this assessment. A simplified assessment for Malaysia is carried out to demonstrate and suggest the use of the proposed methodology. In this exercise, ABWR, AP1000, APR1400 and EPR designs assumed the top-ranks of proven technology candidates according to Malaysia's definition of "proven technology".

Prospects for Nuclear Electric Propulsion Using Closed-Cycle Magnetohydrodynamic Energy Conversion

NASA Technical Reports Server (NTRS)

Litchford, R. J.; Bitteker, L. J.; Jones, J. E.

2001-01-01

Nuclear electric propulsion (NEP) has long been recognized as a major enabling technology for scientific and human exploration of the solar system, and it may conceivably form the basis of a cost-effective space transportation system suitable for space commerce. The chief technical obstacles to realizing this vision are the development of efficient, high-power (megawatt-class) electric thrusters and the development of low specific mass (less than 1 kg/kWe) power plants. Furthermore, comprehensive system analyses of multimegawatt class NEP systems are needed in order to critically assess mission capability and cost attributes. This Technical Publication addresses some of these concerns through a systematic examination of multimegawatt space power installations in which a gas-cooled nuclear reactor is used to drive a magnetohydrodynamic (MHD) generator in a closed-loop Brayton cycle. The primary motivation for considering MHD energy conversion is the ability to transfer energy out of a gas that is simply too hot for contact with any solid material. This has several intrinsic advantages including the ability to achieve high thermal efficiency and power density and the ability to reject heat at elevated temperatures. These attributes lead to a reduction in system specific mass below that obtainable with turbine-based systems, which have definite solid temperature limits for reliable operation. Here, the results of a thermodynamic cycle analysis are placed in context with a preliminary system analysis in order to converge on a design space that optimizes performance while remaining clearly within established bounds of engineering feasibility. MHD technology issues are discussed including the conceptual design of a nonequilibrium disk generator and opportunities for exploiting neutron-induced ionization mechanisms as a means of increasing electrical conductivity and enhancing performance and reliability. The results are then used to make a cursory examination of piloted Mars missions during the 2018 opportunity.

Site environmental report for Calendar Year 1994 on radiological and nonradiological parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-30

Battelle Memorial Institute`s nuclear research facilities are currently being maintained in a surveillance and maintenance (S&M) mode with continual decontamination and decommissioning (D&D) activities being conducted under Department of Energy (DOE) Contract W-7405-ENG-92. These activities are referred to under the Contract as the Battelle Columbus Laboratories Decommissioning Project (BCLDP). Operations referenced in this report are performed in support of S&M and D&D activities. Battelle`s King Avenue facility is not considered in this report to the extent that the West Jefferson facility is. The source term at the King Avenue site is a small fraction of the source term at themore » West Jefferson site. Off site levels of radionuclides that could be attributed to the west Jefferson and King Avenue nuclear operations wereindistinguishable from background levels at specific locations where air, water, and direct radiation measurements were performed. Environmental monitoring continued to demonstrate compliance by Battelle with federal, state and local regulations. Routine, nonradiological activities performed include monitoring liquid effluents and monitoring the ground water system for the West Jefferson North site. Samples of various environmental media including air, water, grass, fish, field and garden crops, sediment and soil were collected from the region surrounding the two sites and analyzed.« less

77 FR 6598 - In the Matter of Entergy Nuclear Operations, Inc., Palisades Nuclear Plant, 27780 Blue Star...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

... through Entergy Nuclear Management Manual EN-OP-115, Revision 9, ``Conduct of Operations.'' Specifically... underlying the apparent violation. These actions included: (a) Operations management conducted a briefing for... the timely notification of events; (b) Management conducted a comprehensive assessment during the week...

10 CFR 810.10 - Grant of specific authorization.

Code of Federal Regulations, 2011 CFR

2011-01-01

... “sensitive nuclear technology” as defined in § 810.3, the requirements of sections 127 and 128 of the Atomic... is required may apply for the authorization to the U.S. Department of Energy, National Nuclear Security Administration, Washington, DC 20585, Attention: Director, Nuclear Transfer and Supplier Policy...

10 CFR 810.10 - Grant of specific authorization.

Code of Federal Regulations, 2010 CFR

2010-01-01

... “sensitive nuclear technology” as defined in § 810.3, the requirements of sections 127 and 128 of the Atomic... is required may apply for the authorization to the U.S. Department of Energy, National Nuclear Security Administration, Washington, DC 20585, Attention: Director, Nuclear Transfer and Supplier Policy...

Kpna7 interacts with egg-specific nuclear factors in rainbow trout (Oncorhynchus mykiss)

USDA-ARS?s Scientific Manuscript database

Nuclear proteins are required for initiation of transcription in early embryos before embryonic genome activation. The regulation of transportation of nuclear proteins is mediated by transport factors known as importins (karyopherins). Kpna7 is a newly discovered member of the importin a family, whi...

78 FR 70588 - STP Nuclear Operating Company; South Texas Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-26

... efficiency; (8) wind power; (9) solar power; (10) hydroelectric power; (11) ocean wave and current energy... generic environmental impact statement for license renewal of nuclear plants; issuance. SUMMARY: Notice is hereby given that the U.S. Nuclear Regulatory Commission (NRC) has published the final, plant-specific...

78 FR 68101 - Environmental Issues Associated With New Reactors and Specific Environmental Guidance for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-13

... October 15, 2013. The Nuclear Energy Institute (NEI) submitted a letter on September 17, 2013 (Agencywide... NUCLEAR REGULATORY COMMISSION [NRC-2013-0212: NRC-2013-0211] Environmental Issues Associated With... AGENCY: Nuclear Regulatory Commission. ACTION: Draft interim staff guidance; re-opening of comment period...

10 CFR 74.33 - Nuclear material control and accounting for uranium enrichment facilities authorized to produce...

Code of Federal Regulations, 2011 CFR

2011-01-01

... enrichment facilities authorized to produce special nuclear material of low strategic significance. 74.33... NUCLEAR MATERIAL Special Nuclear Material of Low Strategic Significance § 74.33 Nuclear material control... strategic significance. (a) General performance objectives. Each licensee who is authorized by this chapter...

Exploring the Relationship of Organizational Culture and Implicit Leadership Theory to Performance Differences in the Nuclear and Fossil Energy Industry

NASA Astrophysics Data System (ADS)

Cravey, Kristopher J.

Notable performance differences exist between nuclear and fossil power generation plants in areas such as safety, outage duration efficiency, and capacity factor. This study explored the relationship of organizational culture and implicit leadership theory to these performance differences. A mixed methods approach consisting of quantitative instruments, namely the Organizational Culture Assessment Instrument and the GLOBE Leadership Scales, and qualitative interviews were used in this study. Subjects were operations middle managers in a U.S. energy company that serves nuclear or fossil power plants. Results from the quantitative instruments revealed no differences between nuclear and fossil groups in regards to organizational culture types and implicit leadership theories. However, the qualitative results did reveal divergence between the two groups in regards to what is valued in the organization and how that drives behaviors and decision making. These organizational phenomenological differences seem to explain why performance differences exist between nuclear and fossil plants because, ultimately, they affect how the organization functions.

Design and performance of A 3He-free coincidence counter based on parallel plate boron-lined proportional technology

DOE PAGES

Henzlova, D.; Menlove, H. O.; Marlow, J. B.

2015-07-01

Thermal neutron counters utilized and developed for deployment as non-destructive assay (NDA) instruments in the field of nuclear safeguards traditionally rely on 3He-based proportional counting systems. 3He-based proportional counters have provided core NDA detection capabilities for several decades and have proven to be extremely reliable with range of features highly desirable for nuclear facility deployment. Facing the current depletion of 3He gas supply and the continuing uncertainty of options for future resupply, a search for detection technologies that could provide feasible short-term alternative to 3He gas was initiated worldwide. As part of this effort, Los Alamos National Laboratory (LANL) designedmore » and built a 3He-free full scale thermal neutron coincidence counter based on boron-lined proportional technology. The boronlined technology was selected in a comprehensive inter-comparison exercise based on its favorable performance against safeguards specific parameters. This paper provides an overview of the design and initial performance evaluation of the prototype High Level Neutron counter – Boron (HLNB). The initial results suggest that current HLNB design is capable to provide ~80% performance of a selected reference 3He-based coincidence counter (High Level Neutron Coincidence Counter, HLNCC). Similar samples are expected to be measurable in both systems, however, slightly longer measurement times may be anticipated for large samples in HLNB. The initial evaluation helped to identify potential for further performance improvements via additional tailoring of boron-layer thickness.« less

10 CFR 830.201 - Performance of work.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Performance of work. 830.201 Section 830.201 Energy DEPARTMENT OF ENERGY NUCLEAR SAFETY MANAGEMENT Safety Basis Requirements § 830.201 Performance of work. A contractor must perform work in accordance with the safety basis for a hazard category 1, 2, or 3 DOE nuclear...

Phosphatidylserine colocalizes with epichromatin in interphase nuclei and mitotic chromosomes

PubMed Central

Prudovsky, Igor; Vary, Calvin P.H.; Markaki, Yolanda; Olins, Ada L.; Olins, Donald E.

2012-01-01

Cycling eukaryotic cells rapidly re-establish the nuclear envelope and internal architecture following mitosis. Studies with a specific anti-nucleosome antibody recently demonstrated that the surface (“epichromatin”) of interphase and mitotic chromatin possesses a unique and conserved conformation, suggesting a role in postmitotic nuclear reformation. Here we present evidence showing that the anionic glycerophospholipid phosphatidylserine is specifically located in epichromatin throughout the cell cycle and is associated with nucleosome core histones. This suggests that chromatin bound phosphatidylserine may function as a nucleation site for the binding of ER and re-establishment of the nuclear envelope. PMID:22555604

The impact of radioactive steel recycling on the public and professionals.

PubMed

Hrncir, Tomas; Panik, Michal; Ondra, Frantisek; Necas, Vladimir

2013-06-15

The decommissioning of nuclear power plants represents a complex process resulting in the generation of large amounts of waste materials, e.g. steel scrap containing various concentrations of radionuclides. Recycling some of these materials is highly desirable due to numerous reasons. Herein presented scenarios of recycling of radioactive steel within the nuclear as well as civil engineering industry are analyzed from the radiation protection point of view. An approach based on the dose constraints principle is chosen. The aim of the study is to derive conditional clearance levels (maximal specific mass activity of material allowing its recycling/clearance) for analyzed radionuclides ensuring that the detrimental impact on human health is kept on a negligible level. Determined conditional clearance levels, as the result of performed software calculations, are valid for the reuse of radioactive steel in four selected scenarios. Calculation results indicate that the increase of the amount of recyclable radioactive steel due to its reuse in specific applications may be feasible considering the radiation impact on the public and professionals. However, issues connected with public acceptance, technical difficulties and financing of potential realization are still open and they have to be examined in more detail. Copyright © 2013 Elsevier B.V. All rights reserved.

Final waste forms project: Performance criteria for phase I treatability studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilliam, T.M.; Hutchins, D.A.; Chodak, P. III

1994-06-01

This document defines the product performance criteria to be used in Phase I of the Final Waste Forms Project. In Phase I, treatability studies will be performed to provide {open_quotes}proof-of-principle{close_quotes} data to establish the viability of stabilization/solidification (S/S) technologies. This information is required by March 1995. In Phase II, further treatability studies, some at the pilot scale, will be performed to provide sufficient data to allow treatment alternatives identified in Phase I to be more fully developed and evaluated, as well as to reduce performance uncertainties for those methods chosen to treat a specific waste. Three main factors influence themore » development and selection of an optimum waste form formulation and hence affect selection of performance criteria. These factors are regulatory, process-specific, and site-specific waste form standards or requirements. Clearly, the optimum waste form formulation will require consideration of performance criteria constraints from each of the three categories. Phase I will focus only on the regulatory criteria. These criteria may be considered the minimum criteria for an acceptable waste form. In other words, a S/S technology is considered viable only if it meet applicable regulatory criteria. The criteria to be utilized in the Phase I treatability studies were primarily taken from Environmental Protection Agency regulations addressed in 40 CFR 260 through 265 and 268; and Nuclear Regulatory Commission regulations addressed in 10 CFR 61. Thus the majority of the identified criteria are independent of waste form matrix composition (i.e., applicable to cement, glass, organic binders etc.).« less

Lifetime attributable risk as an alternative to effective dose to describe the risk of cancer for patients in diagnostic and therapeutic nuclear medicine.

PubMed

Andersson, Martin; Eckerman, Keith; Mattsson, Sören

2017-11-21

The aim of this study is to implement lifetime attributable risk (LAR) predictions of cancer for patients of various age and gender, undergoing diagnostic investigations or treatments in nuclear medicine and to compare the outcome with a population risk estimate using effective dose and the International Commission on Radiological Protection risk coefficients. The radiation induced risk of cancer occurrence (incidence) or death from four nuclear medicine procedures are estimated for both male and female between 0 and 120 years. Estimations of cancer risk are performed using recommended administered activities for two diagnostic ( 18 F-FDG and 99m Tc-phosphonate complex) and two therapeutic ( 131 I-iodide and 223 Ra-dichloride) radiopharmaceuticals to illustrate the use of cancer risk estimations in nuclear medicine. For 18 F-FDG, the cancer incidence for a male of 5, 25, 50 and 75 years at exposure is 0.0021, 0.0010, 0.0008 and 0.0003, respectively. For 99m Tc phosphonates complex the corresponding values are 0.000 59, 0.000 34, 0.000 27 and 0.000 13, respectively. For an 131 I-iodide treatment with 3.7 GBq and 1% uptake 24 h after administration, the cancer incidence for a male of 25, 50 and 75 years at exposure is 0.041, 0.029 and 0.012, respectively. For 223 Ra-dichloride with an administration of 21.9 MBq the cancer incidence for a male of 25, 50 and 75 years is 0.31, 0.21 and 0.09, respectively. The LAR estimations are more suitable in health care situations involving individual patients or specific groups of patients than the health detriment based on effective dose, which represents a population average. The detriment consideration in effective dose adjusts the cancer incidence for suffering of non-lethal cancers while LAR predicts morbidity (incidence) or mortality (cancer). The advantages of these LARs are that they are gender and age specific, allowing risk estimations for specific patients or subgroups thus better representing individuals in health care than effective dose.

Lifetime attributable risk as an alternative to effective dose to describe the risk of cancer for patients in diagnostic and therapeutic nuclear medicine

NASA Astrophysics Data System (ADS)

Andersson, Martin; Eckerman, Keith; Mattsson, Sören

2017-12-01

The aim of this study is to implement lifetime attributable risk (LAR) predictions of cancer for patients of various age and gender, undergoing diagnostic investigations or treatments in nuclear medicine and to compare the outcome with a population risk estimate using effective dose and the International Commission on Radiological Protection risk coefficients. The radiation induced risk of cancer occurrence (incidence) or death from four nuclear medicine procedures are estimated for both male and female between 0 and 120 years. Estimations of cancer risk are performed using recommended administered activities for two diagnostic (18F-FDG and 99mTc-phosphonate complex) and two therapeutic (131I-iodide and 223Ra-dichloride) radiopharmaceuticals to illustrate the use of cancer risk estimations in nuclear medicine. For 18F-FDG, the cancer incidence for a male of 5, 25, 50 and 75 years at exposure is 0.0021, 0.0010, 0.0008 and 0.0003, respectively. For 99mTc phosphonates complex the corresponding values are 0.000 59, 0.000 34, 0.000 27 and 0.000 13, respectively. For an 131I-iodide treatment with 3.7 GBq and 1% uptake 24 h after administration, the cancer incidence for a male of 25, 50 and 75 years at exposure is 0.041, 0.029 and 0.012, respectively. For 223Ra-dichloride with an administration of 21.9 MBq the cancer incidence for a male of 25, 50 and 75 years is 0.31, 0.21 and 0.09, respectively. The LAR estimations are more suitable in health care situations involving individual patients or specific groups of patients than the health detriment based on effective dose, which represents a population average. The detriment consideration in effective dose adjusts the cancer incidence for suffering of non-lethal cancers while LAR predicts morbidity (incidence) or mortality (cancer). The advantages of these LARs are that they are gender and age specific, allowing risk estimations for specific patients or subgroups thus better representing individuals in health care than effective dose.

The Selenocysteine-Specific Elongation Factor Contains Unique Sequences That Are Required for Both Nuclear Export and Selenocysteine Incorporation.

PubMed

Dubey, Aditi; Copeland, Paul R

2016-01-01

Selenocysteine (Sec) is a critical residue in at least 25 human proteins that are essential for antioxidant defense and redox signaling in cells. Sec is inserted into proteins cotranslationally by the recoding of an in-frame UGA termination codon to a Sec codon. In eukaryotes, this recoding event requires several specialized factors, including a dedicated, Sec-specific elongation factor called eEFSec, which binds Sec-tRNASec with high specificity and delivers it to the ribosome for selenoprotein production. Unlike most translation factors, including the canonical elongation factor eEF1A, eEFSec readily localizes to the nucleus of mammalian cells and shuttles between the cytoplasmic and nuclear compartments. The functional significance of eEFSec's nuclear localization has remained unclear. In this study, we have examined the subcellular localization of eEFSec in the context of altered Sec incorporation to demonstrate that reduced selenoprotein production does not correlate with changes in the nuclear localization of eEFSec. In addition, we identify several novel sequences of the protein that are essential for localization as well as Sec insertion activity, and show that eEFSec utilizes CRM1-mediated nuclear export pathway. Our findings argue for two distinct pools of eEFSec in the cell, where the cytoplasmic pool participates in Sec incorporation and the nuclear pool may be involved in an as yet unknown function.

Nuclear Thermal Propulsion Development Risks

NASA Technical Reports Server (NTRS)

Kim, Tony

2015-01-01

There are clear advantages of development of a Nuclear Thermal Propulsion (NTP) for a crewed mission to Mars. NTP for in-space propulsion enables more ambitious space missions by providing high thrust at high specific impulse ((is) approximately 900 sec) that is 2 times the best theoretical performance possible for chemical rockets. Missions can be optimized for maximum payload capability to take more payload with reduced total mass to orbit; saving cost on reduction of the number of launch vehicles needed. Or missions can be optimized to minimize trip time significantly to reduce the deep space radiation exposure to the crew. NTR propulsion technology is a game changer for space exploration to Mars and beyond. However, 'NUCLEAR' is a word that is feared and vilified by some groups and the hostility towards development of any nuclear systems can meet great opposition by the public as well as from national leaders and people in authority. The public often associates the 'nuclear' word with weapons of mass destruction. The development NTP is at risk due to unwarranted public fears and clear honest communication of nuclear safety will be critical to the success of the development of the NTP technology. Reducing cost to NTP development is critical to its acceptance and funding. In the past, highly inflated cost estimates of a full-scale development nuclear engine due to Category I nuclear security requirements and costly regulatory requirements have put the NTP technology as a low priority. Innovative approaches utilizing low enriched uranium (LEU). Even though NTP can be a small source of radiation to the crew, NTP can facilitate significant reduction of crew exposure to solar and cosmic radiation by reducing trip times by 3-4 months. Current Human Mars Mission (HMM) trajectories with conventional propulsion systems and fuel-efficient transfer orbits exceed astronaut radiation exposure limits. Utilizing extra propellant from one additional SLS launch and available energy in the NTP fuel, HMM radiation exposure can be reduced significantly.

Environmental Cracking and Irradiation Resistant Stainless Steels by Additive Manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rebak, Raul B.; Lou, Xiaoyuan

Metal additive manufacturing (AM), or metal 3D printing is an emergent advanced manufacturing method that can create near net shape geometries directly from computer models. This technology can provide the capability to rapidly fabricate complex parts that may be required to enhance the integrity of reactor internals components. Such opportunities may be observed during a plant refueling outage and AM parts can be rapidly custom designed, manufactured and deployed within the outage interval. Additive manufacturing of stainless steel (SS) components can add business benefits on fast delivery on repair hardware, installation tooling, new design prototypes tests, etc. For the nuclearmore » industry, the supply chain is always an issue for reactor service. AM can provide through-life supply chain (40-60 years) for high-value low-volume components. In the meantime, the capability of generating complex geometries and functional gradient materials will improve the performance, reduce the overall component cost, plant asset management cost and increase the plant reliability by the improvement in materials performance in nuclear environments. While extensive work has been conducted regarding additively manufacturing of austenitic SS parts, most efforts focused only on basic attributes such as porosity, residual stress, basic tensile properties, along with components yield and process monitoring. Little work has been done to define and evaluate the material requirements for nuclear applications. Technical gaps exist, which limit this technology adoption in the nuclear industry, which includes high manufacturing cost, unknown risks, limited nuclear related data, lack of specification and qualification methods, and no prior business experience. The main objective of this program was to generate research data to address all these technical gaps and establish a commercial practice to use AM technology in the nuclear power industry. The detailed objectives are listed as follows: (1) Evaluate nuclear related properties of AM 316L SS, including microstructure, tensile properties, impact toughness, stress corrosion cracking (SCC), corrosion fatigue (CF), irradiation effects, and irradiation assisted stress corrosion cracking (IASCC). (2) Understand the correlations among laser processing, heat treatment, microstructure and SCC/irradiation properties; (3) Optimize and improve the manufacturing process to achieve enhanced nuclear application properties; (4) Fabricate, evaluate, qualify and test a prototype reactor component to demonstrate the commercial viability and cost benefit; (5) Create regulatory approval path and commercialization plans for the production of a commercial reactor component.« less

Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference; Sessions 1--8

DOE Office of Scientific and Technical Information (OSTI.GOV)

First, M.W.

1991-02-01

Separate abstracts have been prepared for the papers presented at the meeting on nuclear facility air cleaning technology in the following specific areas of interest: air cleaning technologies for the management and disposal of radioactive wastes; Canadian waste management program; radiological health effects models for nuclear power plant accident consequence analysis; filter testing; US standard codes on nuclear air and gas treatment; European community nuclear codes and standards; chemical processing off-gas cleaning; incineration and vitrification; adsorbents; nuclear codes and standards; mathematical modeling techniques; filter technology; safety; containment system venting; and nuclear air cleaning programs around the world. (MB)

A didactic proposal about Rutherford backscattering spectrometry with theoretic, experimental, simulation and application activities

NASA Astrophysics Data System (ADS)

Corni, Federico; Michelini, Marisa

2018-01-01

Rutherford backscattering spectrometry is a nuclear analysis technique widely used for materials science investigation. Despite the strict technical requirements to perform the data acquisition, the interpretation of a spectrum is within the reach of general physics students. The main phenomena occurring during a collision between helium ions—with energy of a few MeV—and matter are: elastic nuclear collision, elastic scattering, and, in the case of non-surface collision, ion stopping. To interpret these phenomena, we use classical physics models: material point elastic collision, unscreened Coulomb scattering, and inelastic energy loss of ions with electrons, respectively. We present the educational proposal for Rutherford backscattering spectrometry, within the framework of the model of educational reconstruction, following a rationale that links basic physics concepts with quantities for spectra analysis. This contribution offers the opportunity to design didactic specific interventions suitable for undergraduate and secondary school students.

TLX: A master regulator for neural stem cell maintenance and neurogenesis.

PubMed

Islam, Mohammed M; Zhang, Chun-Li

2015-02-01

The orphan nuclear receptor TLX, also known as NR2E1, is an essential regulator of neural stem cell (NSC) self-renewal, maintenance, and neurogenesis. In vertebrates, TLX is specifically localized to the neurogenic regions of the forebrain and retina throughout development and adulthood. TLX regulates the expression of genes involved in multiple pathways, such as the cell cycle, DNA replication, and cell adhesion. These roles are primarily performed through the transcriptional repression or activation of downstream target genes. Emerging evidence suggests that the misregulation of TLX might play a role in the onset and progression of human neurological disorders making this factor an ideal therapeutic target. Here, we review the current understanding of TLX function, expression, regulation, and activity significant to NSC maintenance, adult neurogenesis, and brain plasticity. This article is part of a Special Issue entitled: Nuclear receptors in animal development. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of severe accident risks: Quantification of major input parameters: MAACS (MELCOR Accident Consequence Code System) input

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprung, J.L.; Jow, H-N; Rollstin, J.A.

1990-12-01

Estimation of offsite accident consequences is the customary final step in a probabilistic assessment of the risks of severe nuclear reactor accidents. Recently, the Nuclear Regulatory Commission reassessed the risks of severe accidents at five US power reactors (NUREG-1150). Offsite accident consequences for NUREG-1150 source terms were estimated using the MELCOR Accident Consequence Code System (MACCS). Before these calculations were performed, most MACCS input parameters were reviewed, and for each parameter reviewed, a best-estimate value was recommended. This report presents the results of these reviews. Specifically, recommended values and the basis for their selection are presented for MACCS atmospheric andmore » biospheric transport, emergency response, food pathway, and economic input parameters. Dose conversion factors and health effect parameters are not reviewed in this report. 134 refs., 15 figs., 110 tabs.« less

Oscillator strengths, first-order properties, and nuclear gradients for local ADC(2).

PubMed

Schütz, Martin

2015-06-07

We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.

Impact of the 26mAl(p, γ) reaction to galactic 26Al yield

NASA Astrophysics Data System (ADS)

Kahl, D.; Shimizu, H.; Yamaguchi, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Chen, A. A.; Ge, Z.; Hayakawa, S.; Imai, N.; Iwasa, N.; Kim, A.; Kim, D. H.; Kim, M. J.; Kubono, S.; Kwag, M. S.; Liang, J.; Moon, J. Y.; Nishimura, S.; Oka, S.; Park, S. Y.; Psaltis, A.; Teranishi, T.; Ueno, Y.; Yang, L.

2018-04-01

Astrophysical observables that are directly linked to nuclear physics inputs provide critical and stringent constraints on nucleosynthetic models. As 26Al was the first specific radioactivity observed in the Galaxy, its origin has fascinated the nuclear astrophysics community for nearly forty years. Despite extensive research, the precise origins of 26Al remain elusive. At present, the sum of all putative stellar contributions generally overestimates the 26Al mass in the interstellar medium. Among the many reactions that influence the yield of 26Al, radiative proton capture on its isomer 26mAl is one of the least constrained reactions by experimental data. To this end, we developed a 26Al isomeric beam and performed proton elastic scattering to search for low-spin states in 27Si. The experimental method and the preliminary results of this on-going study will be presented.

Initial Investigation of preclinical integrated SPECT and MR imaging.

PubMed

Hamamura, Mark J; Ha, Seunghoon; Roeck, Werner W; Wagenaar, Douglas J; Meier, Dirk; Patt, Bradley E; Nalcioglu, Orhan

2010-02-01

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmium-zinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source.

Initial Investigation of Preclinical Integrated SPECT and MR Imaging

PubMed Central

Hamamura, Mark J.; Ha, Seunghoon; Roeck, Werner W.; Wagenaar, Douglas J.; Meier, Dirk; Patt, Bradley E.; Nalcioglu, Orhan

2014-01-01

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmium-zinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source. PMID:20082527

Design consideration for a nuclear electric propulsion system

NASA Technical Reports Server (NTRS)

Phillips, W. M.; Pawlik, E. V.

1978-01-01

A study is currently underway to design a nuclear electric propulsion vehicle capable of performing detailed exploration of the outer-planets. Primary emphasis is on the power subsystem. Secondary emphasis includes integration into a spacecraft, and integration with the thrust subsystem and science package or payload. The results of several design iterations indicate an all-heat-pipe system offers greater reliability, elimination of many technology development areas and a specific weight of under 20 kg/kWe at the 400 kWe power level. The system is compatible with a single Shuttle launch and provides greater safety than could be obtained with designs using pumped liquid metal cooling. Two configurations, one with the reactor and power conversion forward on the spacecraft with the ion engines aft and the other with reactor, power conversion and ion engines aft were selected as dual baseline designs based on minimum weight, minimum required technology development and maximum growth potential and flexibility.

Arranging eukaryotic nuclear DNA polymerases for replication: Specific interactions with accessory proteins arrange Pols α, δ, and ϵ in the replisome for leading-strand and lagging-strand DNA replication.

PubMed

Kunkel, Thomas A; Burgers, Peter M J

2017-08-01

Biochemical and cryo-electron microscopy studies have just been published revealing interactions among proteins of the yeast replisome that are important for highly coordinated synthesis of the two DNA strands of the nuclear genome. These studies reveal key interactions important for arranging DNA polymerases α, δ, and ϵ for leading and lagging strand replication. The CMG (Mcm2-7, Cdc45, GINS) helicase is central to this interaction network. These are but the latest examples of elegant studies performed in the recent past that lead to a much better understanding of how the eukaryotic replication fork achieves efficient DNA replication that is accurate enough to prevent diseases yet allows evolution. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Fan W.; Contescu, Cristian I.; Gallego, Nidia C.

Laser ultrasonic line source methods have been used to study elastic anisotropy in nuclear graphites by measuring shear wave birefringence. Depending on the manufacturing processes used during production, nuclear graphites can exhibit various degrees of material anisotropy related to preferred crystallite orientation and to microcracking. In this paper, laser ultrasonic line source measurements of shear wave birefringence on NBG-25 have been performed to assess elastic anisotropy. Laser line sources allow specific polarizations for shear waves to be transmitted – the corresponding wavespeeds can be used to compute bulk, elastic moduli that serve to quantify anisotropy. These modulus values can bemore » interpreted using physical property models based on orientation distribution coefficients and microcrack-modified, single crystal moduli to represent the combined effects of crystallite orientation and microcracking on material anisotropy. Finally, ultrasonic results are compared to and contrasted with measurements of anisotropy based on the coefficient of thermal expansion to show the relationship of results from these techniques.« less

Predicting the Lifetimes of Nuclear Waste Containers

NASA Astrophysics Data System (ADS)

King, Fraser

2014-03-01

As for many aspects of the disposal of nuclear waste, the greatest challenge we have in the study of container materials is the prediction of the long-term performance over periods of tens to hundreds of thousands of years. Various methods have been used for predicting the lifetime of containers for the disposal of high-level waste or spent fuel in deep geological repositories. Both mechanical and corrosion-related failure mechanisms need to be considered, although until recently the interactions of mechanical and corrosion degradation modes have not been considered in detail. Failure from mechanical degradation modes has tended to be treated through suitable container design. In comparison, the inevitable loss of container integrity due to corrosion has been treated by developing specific corrosion models. The most important aspect, however, is to be able to justify the long-term predictions by demonstrating a mechanistic understanding of the various degradation modes.

Lawrence Livermore National Laboratory and Sandia National Laboratory Nuclear Accident Dosimetry Support of IER 252 and the Dose Characterization of the Flattop Reactor at the DAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hickman, D. P.; Jeffers, K. L.; Radev, R. P.

In support of IER 252 “Characterization of the Flattop Reactor at the NCERC”, LLNL performed ROSPEC measurements of the neutron spectrum and deployed 129 Personnel Nuclear Accident Dosimeters (PNAD) to establish the need for height corrections and verification of neutron spectrum evaluation of the fluences and dose. A very limited number of heights (typically only one or two heights) can be measured using neutron spectrometers, therefore it was important to determine if any height correction would be needed in future intercomparisons and studies. Specific measurement positions around the Flatttop reactor are provided in Figure 1. Table 1 provides run andmore » position information for LLNL measurements. The LLNL ROSPEC (R2) was used for run numbers 1 – 7, and vi. PNADs were positioned on trees during run numbers 9, 11, and 13.« less

Analysis of sheltering and evacuation strategies for a national capital region nuclear detonation scenario.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshimura, Ann S.; Brandt, Larry D.

2011-12-01

Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kT detonation in the National Capital Region. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternativesmore » at one exemplary point. For most Washington, DC neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.« less

Pulmonary disorder and present nuclear denotation: A brief summary

PubMed Central

Wiwanitkit, Viroj

2011-01-01

There are many health effects caused by leaked radiation from damaged reactors of a nuclear power plant. However, the effect on pulmonary system is not reported much. Focusing on the present nuclear denotation crisis in Japan, it is wise to review on the specific issue of pulmonary disorder and nuclear denotation. Several disorders of interest, including malignancy and non-malignancy disorders, are mentioned in the literature. PMID:21760839

Importin-7 Mediates Nuclear Trafficking of DNA in Mammalian Cells

PubMed Central

Dhanoya, Arjun; Wang, Tse; Keshavarz-Moore, Eli; Fassati, Ariberto; Chain, Benjamin M

2013-01-01

Eukaryotic cells have the ability to uptake and transport endogenous and exogenous DNA in their nuclei, however little is known about the specific pathways involved. Here we show that the nuclear transport receptor importin 7 (imp7) supports nuclear import of supercoiled plasmid DNA and human mitochondrial DNA in a Ran and energy-dependent way. The imp7-dependent pathway was specifically competed by excess DNA but not by excess of maltose-binding protein fused with the classical nuclear localizing signal (NLS) or the M9 peptides. Transport of DNA molecules complexed with poly-l-lysine was impaired in intact cells depleted of imp7, and DNA complexes remained localized in the cytoplasm. Poor DNA nuclear import in cells depleted of imp7 directly correlated with lower gene expression levels in these cells compared to controls. Inefficient nuclear import of transfected DNA induced greater upregulation of the interferon pathway, suggesting that rapid DNA nuclear import may prevent uncontrolled activation of the innate immune response. Our results provide evidence that imp7 is a non-redundant component of an intrinsic pathway in mammalian cells for efficient accumulation of exogenous and endogenous DNA in the nucleus, which may be critical for the exchange of genetic information between mitochondria and nuclear genomes and to control activation of the innate immune response. PMID:23067392

Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryantsev, A.L.; Chechenova, M.B.; Shelden, E.A.

During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absencemore » of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.« less

Imaging analysis of nuclear antiviral factors through direct detection of incoming adenovirus genome complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komatsu, Tetsuro; Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba 305-8575; Will, Hans

2016-04-22

Recent studies involving several viral systems have highlighted the importance of cellular intrinsic defense mechanisms through nuclear antiviral proteins that restrict viral propagation. These factors include among others components of PML nuclear bodies, the nuclear DNA sensor IFI16, and a potential restriction factor PHF13/SPOC1. For several nuclear replicating DNA viruses, it was shown that these factors sense and target viral genomes immediately upon nuclear import. In contrast to the anticipated view, we recently found that incoming adenoviral genomes are not targeted by PML nuclear bodies. Here we further explored cellular responses against adenoviral infection by focusing on specific conditions asmore » well as additional nuclear antiviral factors. In line with our previous findings, we show that neither interferon treatment nor the use of specific isoforms of PML nuclear body components results in co-localization between incoming adenoviral genomes and the subnuclear domains. Furthermore, our imaging analyses indicated that neither IFI16 nor PHF13/SPOC1 are likely to target incoming adenoviral genomes. Thus our findings suggest that incoming adenoviral genomes may be able to escape from a large repertoire of nuclear antiviral mechanisms, providing a rationale for the efficient initiation of lytic replication cycle. - Highlights: • Host nuclear antiviral factors were analyzed upon adenovirus genome delivery. • Interferon treatments fail to permit PML nuclear bodies to target adenoviral genomes. • Neither Sp100A nor B targets adenoviral genomes despite potentially opposite roles. • The nuclear DNA sensor IFI16 does not target incoming adenoviral genomes. • PHF13/SPOC1 targets neither incoming adenoviral genomes nor genome-bound protein VII.« less

Cytological Evaluation of Thyroid Lesions by Nuclear Morphology and Nuclear Morphometry.

PubMed

Yashaswini, R; Suresh, T N; Sagayaraj, A

2017-01-01

Fine needle aspiration (FNA) of the thyroid gland is an effective diagnostic method. The Bethesda system for reporting thyroid cytopathology classifies them into six categories and gives implied risk for malignancy and management protocol in each category. Though the system gives specific criteria, diagnostic dilemma still exists. Using nuclear morphometry, we can quantify the number of parameters, such as those related to nuclear size and shape. The evaluation of nuclear morphometry is not well established in thyroid cytology. To classify thyroid lesions on fine needle aspiration cytology (FNAC) using Bethesda system and to evaluate the significance of nuclear parameters in improving the prediction of thyroid malignancy. In the present study, 120 FNAC cases of thyroid lesions with histological diagnosis were included. Computerized nuclear morphometry was done on 81 cases which had confirmed cytohistological correlation, using Aperio computer software. One hundred nuclei from each case were outlined and eight nuclear parameters were analyzed. In the present study, thyroid lesions were common in female with M: F ratio of 1:5 and most commonly in 40-60 yrs. Under Bethesda system, 73 (60.83%) were category II; 14 (11.6%) were category III, 3 (2.5%) were category IV, 8 (6.6%) were category V, and 22 (18.3%) were category VI, which were malignant on histopathological correlation. Sensitivity, specificity, and diagnostic accuracy of Bethesda reporting system are 62.5, 84.38, and 74.16%, respectively. Minimal nuclear diameter, maximal nuclear diameter, nuclear perimeter, and nuclear area were higher in malignant group compared to nonneoplastic and benign group. The Bethesda system is a useful standardized system of reporting thyroid cytopathology. It gives implied risk of malignancy. Nuclear morphometry by computerized image analysis can be utilized as an additional diagnostic tool.

A new application of the phase-field method for understanding the mechanisms of nuclear architecture reorganization.

PubMed

Lee, S Seirin; Tashiro, S; Awazu, A; Kobayashi, R

2017-01-01

Specific features of nuclear architecture are important for the functional organization of the nucleus, and chromatin consists of two forms, heterochromatin and euchromatin. Conventional nuclear architecture is observed when heterochromatin is enriched at nuclear periphery, and it represents the primary structure in the majority of eukaryotic cells, including the rod cells of diurnal mammals. In contrast to this, inverted nuclear architecture is observed when the heterochromatin is distributed at the center of the nucleus, which occurs in the rod cells of nocturnal mammals. The inverted architecture found in the rod cells of the adult mouse is formed through the reorganization of conventional architecture during terminal differentiation. Although a previous experimental approach has demonstrated the relationship between these two nuclear architecture types at the molecular level, the mechanisms underlying long-range reorganization processes remain unknown. The details of nuclear structures and their spatial and temporal dynamics remain to be elucidated. Therefore, a comprehensive approach, using mathematical modeling, is required, in order to address these questions. Here, we propose a new mathematical approach to the understanding of nuclear architecture dynamics using the phase-field method. We successfully recreated the process of nuclear architecture reorganization, and showed that it is robustly induced by physical features, independent of a specific genotype. Our study demonstrates the potential of phase-field method application in the life science fields.

Genome-nuclear lamina interactions and gene regulation.

PubMed

Kind, Jop; van Steensel, Bas

2010-06-01

The nuclear lamina, a filamentous protein network that coats the inner nuclear membrane, has long been thought to interact with specific genomic loci and regulate their expression. Molecular mapping studies have now identified large genomic domains that are in contact with the lamina. Genes in these domains are typically repressed, and artificial tethering experiments indicate that the lamina can actively contribute to this repression. Furthermore, the lamina indirectly controls gene expression in the nuclear interior by sequestration of certain transcription factors. A variety of DNA-binding and chromatin proteins may anchor specific loci to the lamina, while histone-modifying enzymes partly mediate the local repressive effect of the lamina. Experimental tools are now available to begin to unravel the underlying molecular mechanisms. Copyright 2010 Elsevier Ltd. All rights reserved.

Audit Report on "The Department's Management of Nuclear Materials Provided to Domestic Licensees"

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The objective if to determine whether the Department of Energy (Department) was adequately managing its nuclear materials provided to domestic licensees. The audit was performed from February 2007 to September 2008 at Department Headquarters in Washington, DC, and Germantown, MD; the Oak Ridge Office and the Oak Ridge National Laboratory in Oak Ridge, TN. In addition, we visited or obtained data from 40 different non-Departmental facilities in various states. To accomplish the audit objective, we: (1) Reviewed Departmental and Nuclear Regulatory Commission (NRC) requirements for the control and accountability of nuclear materials; (2) Analyzed a Nuclear Materials Management and Safeguardsmore » System (NMMSS) report with ending inventory balances for Department-owned nuclear materials dated September 30, 2007, to determine the amount and types of nuclear materials located at non-Department domestic facilities; (3) Held discussions with Department and NRC personnel that used NMMSS information to determine their roles and responsibilities related to the control and accountability over nuclear materials; (4) Selected a judgmental sample of 40 non-Department domestic facilities; (5) Met with licensee officials and sent confirmations to determine whether their actual inventories of Department-owned nuclear materials were consistent with inventories reported in the NMMSS; and, (6) Analyzed historical information related to the 2004 NMMSS inventory rebaselining initiative to determine the quantity of Department-owned nuclear materials that were written off from the domestic licensees inventory balances. This performance audit was conducted in accordance with generally accepted Government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objective. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. The audit included tests of controls and compliance with laws and regulations related to managing the Department-owned nuclear materials provided to non-Departmental domestic licensees. Because our review was limited it would not necessarily have disclosed all internal control deficiencies that may have existed at the time of our audit. We examined the establishment of performance measures in accordance with Government Performance and Results Act of 1993, as they related to the audit objective. We found that the Department had established performance measures related to removing or disposing of nuclear materials and radiological sources around the world. We utilized computer generated data during our audit and performed procedures to validate the reliability of the information as necessary to satisfy our audit objective. As noted in the report, we questioned the reliability of the NMMSS data.« less

Romanian experience on packaging testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieru, G.

2007-07-01

With more than twenty years ago, the Institute for Nuclear Research Pitesti (INR), through its Reliability and Testing Laboratory, was licensed by the Romanian Nuclear Regulatory Body- CNCAN and to carry out qualification tests [1] for packages intended to be used for the transport and storage of radioactive materials. Radioactive materials, generated by Romanian nuclear facilities [2] are packaged in accordance with national [3] and the IAEA's Regulations [1,6] for a safe transport to the disposal center. Subjecting these packages to the normal and simulating test conditions accomplish the evaluation and certification in order to prove the package technical performances.more » The paper describes the qualification tests for type A and B packages used for transport and storage of radioactive materials, during a period of 20 years of experience. Testing is used to substantiate assumption in analytical models and to demonstrate package structural response. The Romanian test facilities [1,3,6] are used to simulate the required qualification tests and have been developed at INR Pitesti, the main supplier of type A packages used for transport and storage of low radioactive wastes in Romania. The testing programme will continue to be a strong option to support future package development, to perform a broad range of verification and certification tests on radioactive material packages or component sections, such as packages used for transport of radioactive sources to be used for industrial or medical purposes [2,8]. The paper describes and contain illustrations showing some of the various tests packages which have been performed during certain periods and how they relate to normal conditions and minor mishaps during transport. Quality assurance and quality controls measures taken in order to meet technical specification provided by the design there are also presented and commented. (authors)« less

A New Capability for Nuclear Thermal Propulsion Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amiri, Benjamin W.; Nuclear and Radiological Engineering Department, University of Florida, Gainesville, FL 32611; Kapernick, Richard J.

2007-01-30

This paper describes a new capability for Nuclear Thermal Propulsion (NTP) design that has been developed, and presents the results of some analyses performed with this design tool. The purpose of the tool is to design to specified mission and material limits, while maximizing system thrust to weight. The head end of the design tool utilizes the ROCket Engine Transient Simulation (ROCETS) code to generate a system design and system design requirements as inputs to the core analysis. ROCETS is a modular system level code which has been used extensively in the liquid rocket engine industry for many years. Themore » core design tool performs high-fidelity reactor core nuclear and thermal-hydraulic design analysis. At the heart of this process are two codes TMSS-NTP and NTPgen, which together greatly automate the analysis, providing the capability to rapidly produce designs that meet all specified requirements while minimizing mass. A PERL based command script, called CORE DESIGNER controls the execution of these two codes, and checks for convergence throughout the process. TMSS-NTP is executed first, to produce a suite of core designs that meet the specified reactor core mechanical, thermal-hydraulic and structural requirements. The suite of designs consists of a set of core layouts and, for each core layout specific designs that span a range of core fuel volumes. NTPgen generates MCNPX models for each of the core designs from TMSS-NTP. Iterative analyses are performed in NTPgen until a reactor design (fuel volume) is identified for each core layout that meets cold and hot operation reactivity requirements and that is zoned to meet a radial core power distribution requirement.« less

Introducing Nuclear Data Evaluations of Prompt Fission Neutron Spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neudecker, Denise

2015-06-17

Nuclear data evaluations provide recommended data sets for nuclear data applications such as reactor physics, stockpile stewardship or nuclear medicine. The evaluated data are often based on information from multiple experimental data sets and nuclear theory using statistical methods. Therefore, they are collaborative efforts of evaluators, theoreticians, experimentalists, benchmark experts, statisticians and application area scientists. In this talk, an introductions is given to the field of nuclear data evaluation at the specific example of a recent evaluation of the outgoing neutron energy spectrum emitted promptly after fission from 239Pu and induced by neutrons from thermal to 30 MeV.

Analysis of the TREAT LEU Conceptual Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connaway, H. M.; Kontogeorgakos, D. C.; Papadias, D. D.

2016-03-01

Analyses were performed to evaluate the performance of the low enriched uranium (LEU) conceptual design fuel for the conversion of the Transient Reactor Test Facility (TREAT) from its current highly enriched uranium (HEU) fuel. TREAT is an experimental nuclear reactor designed to produce high neutron flux transients for the testing of reactor fuels and other materials. TREAT is currently in non-operational standby, but is being restarted under the U.S. Department of Energy’s Resumption of Transient Testing Program. The conversion of TREAT is being pursued in keeping with the mission of the Department of Energy National Nuclear Security Administration’s Material Managementmore » and Minimization (M3) Reactor Conversion Program. The focus of this study was to demonstrate that the converted LEU core is capable of maintaining the performance of the existing HEU core, while continuing to operate safely. Neutronic and thermal hydraulic simulations have been performed to evaluate the performance of the LEU conceptual-design core under both steady-state and transient conditions, for both normal operation and reactivity insertion accident scenarios. In addition, ancillary safety analyses which were performed for previous LEU design concepts have been reviewed and updated as-needed, in order to evaluate if the converted LEU core will function safely with all existing facility systems. Simulations were also performed to evaluate the detailed behavior of the UO 2-graphite fuel, to support future fuel manufacturing decisions regarding particle size specifications. The results of these analyses will be used in conjunction with work being performed at Idaho National Laboratory and Los Alamos National Laboratory, in order to develop the Conceptual Design Report project deliverable.« less

Iterative performance assessments as a regulatory tool for evaluating repository safety: How experiences from SKI Project-90 were used in formulating the new performance assessment project SITE-94

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersson, J.

1993-12-31

The Swedish Nuclear Power Inspectorate, SKI, regulatory research program has to prepare for the process of licensing a repository for spent nuclear fuel, by building up the necessary knowledge and review capacity. SKIs main strategy for meeting this demand is to develop an independent performance assessment capability. SKIs first own performance assessment project, Project-90, was completed in 1991 and is now followed by a new project, SITE-94. SITE-94 is based on conclusions reached within Project-90. An independent review of Project-90, carried out by a NEA team of experts, has also contributed to the formation of the project. Another important reasonmore » for the project is that the implementing organization in Sweden, SKB, has proposed to submit an application to start detailed investigation of a repository candidate site around 1997. SITE-94 is a performance assessment of a hypothetical repository at a real site. The main objective of the project is to determine how site specific data should be assimilated into the performance assessment process, and to evaluate how uncertainties inherent in site characterization will influence performance assessment results. This will be addressed by exploring multiple interpretations, conceptual models, and parameters consistent with the site data. The site evaluation will strive for consistency between geological, hydrological, rock mechanical, and geochemical descriptions. Other important elements of SITE-94 are the development of a practical and defensible methodology for defining, constructing and analyzing scenarios, the development of approaches for treatment of uncertainties, evaluation of canister integrity, and the development and application of an appropriate quality assurance plan for performance assessments.« less

Nuclear Structure of 186Re

DTIC Science & Technology

2016-12-24

D population-depopulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 AME Atomic Mass Evaluation...this mass region are important for validating models of nuclear structure and reactions. The ENSDF feeds a specific data library relevant to nuclear...spherically asymmetric. Spherical asymmetry is common for nuclei between shell closures, such as those in the mid-shell 150  A  190 mass range of interest

Nuclear Reactors for Space Power, Understanding the Atom Series.

ERIC Educational Resources Information Center

Corliss, William R.

The historical development of rocketry and nuclear technology includes a specific description of Systems for Nuclear Auxiliary Power (SNAP) programs. Solar cells and fuel cells are considered as alternative power supplies for space use. Construction and operation of space power plants must include considerations of the transfer of heat energy to…

Denuclearization for a Just World: The Failure of Non Proliferation.

ERIC Educational Resources Information Center

Institute for World Order, New York, NY.

The document discusses the non proliferation policies of nuclear power nations. It specifically focuses on the credibility gap which exists between the actual statements of peaceful intentions made by these nations which express the need for non proliferation of nuclear weapons and their actual conduct with regards to nuclear-related issues in…