10 CFR 72.124 - Criteria for nuclear criticality safety.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Criteria for nuclear criticality safety. 72.124 Section 72.124 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 72.124 - Criteria for nuclear criticality safety.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Criteria for nuclear criticality safety. 72.124 Section 72.124 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 72.124 - Criteria for nuclear criticality safety.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Criteria for nuclear criticality safety. 72.124 Section 72.124 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 72.124 - Criteria for nuclear criticality safety.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Criteria for nuclear criticality safety. 72.124 Section 72.124 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...

Nuclear relaxation and critical fluctuations in membranes containing cholesterol

NASA Astrophysics Data System (ADS)

McConnell, Harden

2009-04-01

Nuclear resonance frequencies in bilayer membranes depend on lipid composition. Our calculations describe the combined effects of composition fluctuations and diffusion on nuclear relaxation near a miscibility critical point. Both tracer and gradient diffusion are included. The calculations involve correlation functions and a correlation length ξ =ξ0T/(T -Tc), where T -Tc is temperature above the critical temperature and ξ0 is a parameter of molecular length. Several correlation functions are examined, each of which is related in some degree to the Ising model correlation function. These correlation functions are used in the calculation of transverse deuterium relaxation rates in magic angle spinning and quadrupole echo experiments. The calculations are compared with experiments that report maxima in deuterium and proton nuclear relaxation rates at the critical temperature [Veatch et al., Proc. Nat. Acad. Sci. U.S.A. 104, 17650 (2007)]. One Ising-model-related correlation function yields a maximum 1/T2 relaxation rate at the critical temperature for both magic angle spinning and quadrupole echo experiments. The calculated rates at the critical temperature are close to the experimental rates. The rate maxima involve relatively rapid tracer diffusion in a static composition gradient over distances of up to 10-100 nm.

SRTC criticality safety technical review: Nuclear Criticality Safety Evaluation 93-04 enriched uranium receipt

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

Rathbun, R.

Review of NMP-NCS-930087, {open_quotes}Nuclear Criticality Safety Evaluation 93-04 Enriched Uranium Receipt (U), July 30, 1993, {close_quotes} was requested of SRTC (Savannah River Technology Center) Applied Physics Group. The NCSE is a criticality assessment to determine the mass limit for Engineered Low Level Trench (ELLT) waste uranium burial. The intent is to bury uranium in pits that would be separated by a specified amount of undisturbed soil. The scope of the technical review, documented in this report, consisted of (1) an independent check of the methods and models employed, (2) independent HRXN/KENO-V.a calculations of alternate configurations, (3) application of ANSI/ANS 8.1,more » and (4) verification of WSRC Nuclear Criticality Safety Manual procedures. The NCSE under review concludes that a 500 gram limit per burial position is acceptable to ensure the burial site remains in a critically safe configuration for all normal and single credible abnormal conditions. This reviewer agrees with that conclusion.« less

Neutron absorbing coating for nuclear criticality control

DOEpatents

Mizia, Ronald E.; Wright, Richard N.; Swank, William D.; Lister, Tedd E.; Pinhero, Patrick J.

2007-10-23

A neutron absorbing coating for use on a substrate, and which provides nuclear criticality control is described and which includes a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight.

Proceedings of the Nuclear Criticality Technology Safety Workshop

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

Rene G. Sanchez

1998-04-01

This document contains summaries of most of the papers presented at the 1995 Nuclear Criticality Technology Safety Project (NCTSP) meeting, which was held May 16 and 17 at San Diego, Ca. The meeting was broken up into seven sessions, which covered the following topics: (1) Criticality Safety of Project Sapphire; (2) Relevant Experiments For Criticality Safety; (3) Interactions with the Former Soviet Union; (4) Misapplications and Limitations of Monte Carlo Methods Directed Toward Criticality Safety Analyses; (5) Monte Carlo Vulnerabilities of Execution and Interpretation; (6) Monte Carlo Vulnerabilities of Representation; and (7) Benchmark Comparisons.

[Chernobyl nuclear power plant accident and Tokaimura criticality accident].

PubMed

Takada, Jun

2012-03-01

It is clear from inspection of historical incidents that the scale of disasters in a nuclear power plant accident is quite low level overwhelmingly compared with a nuclear explosion in nuclear war. Two cities of Hiroshima and Nagasaki were destroyed by nuclear blast with about 20 kt TNT equivalent and then approximately 100,000 people have died respectively. On the other hand, the number of acute death is 30 in the Chernobyl nuclear reactor accident. In this chapter, we review health hazards and doses in two historical nuclear incidents of Chernobyl and Tokaimura criticality accident and then understand the feature of the radiation accident in peaceful utilization of nuclear power.

Nuclear Criticality Experimental Research Center (NCERC) Overview

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

Goda, Joetta Marie; Grove, Travis Justin; Hayes, David Kirk

The mission of the National Criticality Experiments Research Center (NCERC) at the Device Assembly Facility (DAF) is to conduct experiments and training with critical assemblies and fissionable material at or near criticality in order to explore reactivity phenomena, and to operate the assemblies in the regions from subcritical through delayed critical. One critical assembly, Godiva-IV, is designed to operate above prompt critical. The Nuclear Criticality Experimental Research Center (NCERC) is our nation’s only general-purpose critical experiments facility and is only one of a few that remain operational throughout the world. This presentation discusses the history of NCERC, the general activitiesmore » that makeup work at NCERC, and the various government programs and missions that NCERC supports. Recent activities at NCERC will be reviewed, with a focus on demonstrating how NCERC meets national security mission goals using engineering fundamentals. In particular, there will be a focus on engineering theory and design and applications of engineering fundamentals at NCERC. NCERC activities that relate to engineering education will also be examined.« less

PRELIMINARY NUCLEAR CRITICALITY NUCLEAR SAFETY EVLAUATION FOR THE CONTAINER SURVEILLANCE AND STORAGE CAPABILITY PROJECT

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

Low, M; Matthew02 Miller, M; Thomas Reilly, T

2007-04-30

Washington Safety Management Solutions (WSMS) provides criticality safety services to Washington Savannah River Company (WSRC) at the Savannah River Site. One activity at SRS is the Container Surveillance and Storage Capability (CSSC) Project, which will perform surveillances on 3013 containers (hereafter referred to as 3013s) to verify that they meet the Department of Energy (DOE) Standard (STD) 3013 for plutonium storage. The project will handle quantities of material that are greater than ANS/ANSI-8.1 single parameter mass limits, and thus required a Nuclear Criticality Safety Evaluation (NCSE). The WSMS methodology for conducting an NCSE is outlined in the WSMS methods manual.more » The WSMS methods manual currently follows the requirements of DOE-O-420.1B, DOE-STD-3007-2007, and the Washington Savannah River Company (WSRC) SCD-3 manual. DOE-STD-3007-2007 describes how a NCSE should be performed, while DOE-O-420.1B outlines the requirements for a Criticality Safety Program (CSP). The WSRC SCD-3 manual implements DOE requirements and ANS standards. NCSEs do not address the Nuclear Criticality Safety (NCS) of non-reactor nuclear facilities that may be affected by overt or covert activities of sabotage, espionage, terrorism or other security malevolence. Events which are beyond the Design Basis Accidents (DBAs) are outside the scope of a double contingency analysis.« less

Nuclear power systems for lunar and Mars exploration

NASA Technical Reports Server (NTRS)

Sovie, R. J.; Bozek, J. M.

1990-01-01

Initial studies of a variety of mission scenarios for the new Space Exploration Initiative, and the technologies necessary to enable or significantly enhance them, have identified the development of advanced space power systems whether solar, chemical or nuclear to be of prime importance. Lightweight, compact, reliable power systems for planetary rovers and a variety of surface vehicles, utility surface power, and power for advanced propulsion systems have been identified as critical needs for these missions. These mission scenarios, the concomitant power system requirements, and power system options considered are discussed. The significant potential benefits of nuclear power are identified for meeting the power needs of the above applications.

Reactivity impact of {sup 16}O thermal elastic-scattering nuclear data for some numerical and critical benchmark systems

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

Kozier, K. S.; Roubtsov, D.; Plompen, A. J. M.

2012-07-01

The thermal neutron-elastic-scattering cross-section data for {sup 16}O used in various modern evaluated-nuclear-data libraries were reviewed and found to be generally too high compared with the best available experimental measurements. Some of the proposed revisions to the ENDF/B-VII.0 {sup 16}O data library and recent results from the TENDL system increase this discrepancy further. The reactivity impact of revising the {sup 16}O data downward to be consistent with the best measurements was tested using the JENDL-3.3 {sup 16}O cross-section values and was found to be very small in MCNP5 simulations of the UO{sub 2} and reactor-recycle MOX-fuel cases of the ANSmore » Doppler-defect numerical benchmark. However, large reactivity differences of up to about 14 mk (1400 pcm) were observed using {sup 16}O data files from several evaluated-nuclear-data libraries in MCNP5 simulations of the Los Alamos National Laboratory HEU heavy-water solution thermal critical experiments, which were performed in the 1950's. The latter result suggests that new measurements using HEU in a heavy-water-moderated critical facility, such as the ZED-2 zero-power reactor at the Chalk River Laboratories, might help to resolve the discrepancy between the {sup 16}O thermal elastic-scattering cross-section values and thereby reduce or better define its uncertainty, although additional assessment work would be needed to confirm this. (authors)« less

Supervisory Control and Data Acquisition (SCADA) Systems and Cyber-Security: Best Practices to Secure Critical Infrastructure

ERIC Educational Resources Information Center

Morsey, Christopher

2017-01-01

In the critical infrastructure world, many critical infrastructure sectors use a Supervisory Control and Data Acquisition (SCADA) system. The sectors that use SCADA systems are the electric power, nuclear power and water. These systems are used to control, monitor and extract data from the systems that give us all the ability to light our homes…

Activities of the DOE Nuclear Criticality Safety Program (NCSP) at the Oak Ridge Electron Linear Accelerator (ORELA)

NASA Astrophysics Data System (ADS)

Valentine, Timothy E.; Leal, Luiz C.; Guber, Klaus H.

2002-12-01

The Department of Energy established the Nuclear Criticality Safety Program (NCSP) in response to the Recommendation 97-2 by the Defense Nuclear Facilities Safety Board. The NCSP consists of seven elements of which nuclear data measurements and evaluations is a key component. The intent of the nuclear data activities is to provide high resolution nuclear data measurements that are evaluated, validated, and formatted for use by the nuclear criticality safety community to provide improved and reliable calculations for nuclear criticality safety evaluations. High resolution capture, fission, and transmission measurements are performed at the Oak Ridge Electron Linear Accelerator (ORELA) to address the needs of the criticality safety community and to address known deficiencies in nuclear data evaluations. The activities at ORELA include measurements on both light and heavy nuclei and have been used to identify improvements in measurement techniques that greatly improve the measurement of small capture cross sections. The measurement activities at ORELA provide precise and reliable high-resolution nuclear data for the nuclear criticality safety community.

Nuclear Data Needs for Generation IV Nuclear Energy Systems

NASA Astrophysics Data System (ADS)

Rullhusen, Peter

2006-04-01

Nuclear data needs for generation IV systems. Future of nuclear energy and the role of nuclear data / P. Finck. Nuclear data needs for generation IV nuclear energy systems-summary of U.S. workshop / T. A. Taiwo, H. S. Khalil. Nuclear data needs for the assessment of gen. IV systems / G. Rimpault. Nuclear data needs for generation IV-lessons from benchmarks / S. C. van der Marck, A. Hogenbirk, M. C. Duijvestijn. Core design issues of the supercritical water fast reactor / M. Mori ... [et al.]. GFR core neutronics studies at CEA / J. C. Bosq ... [et al]. Comparative study on different phonon frequency spectra of graphite in GCR / Young-Sik Cho ... [et al.]. Innovative fuel types for minor actinides transmutation / D. Haas, A. Fernandez, J. Somers. The importance of nuclear data in modeling and designing generation IV fast reactors / K. D. Weaver. The GIF and Mexico-"everything is possible" / C. Arrenondo Sánchez -- Benmarks, sensitivity calculations, uncertainties. Sensitivity of advanced reactor and fuel cycle performance parameters to nuclear data uncertainties / G. Aliberti ... [et al.]. Sensitivity and uncertainty study for thermal molten salt reactors / A. Biduad ... [et al.]. Integral reactor physics benchmarks- The International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPHEP) / J. B. Briggs, D. W. Nigg, E. Sartori. Computer model of an error propagation through micro-campaign of fast neutron gas cooled nuclear reactor / E. Ivanov. Combining differential and integral experiments on [symbol] for reducing uncertainties in nuclear data applications / T. Kawano ... [et al.]. Sensitivity of activation cross sections of the Hafnium, Tanatalum and Tungsten stable isotopes to nuclear reaction mechanisms / V. Avrigeanu ... [et al.]. Generating covariance data with nuclear models / A. J. Koning. Sensitivity of Candu-SCWR reactors physics calculations to nuclear data files / K. S

Dual annular rotating "windowed" nuclear reflector reactor control system

DOEpatents

Jacox, Michael G.; Drexler, Robert L.; Hunt, Robert N. M.; Lake, James A.

1994-01-01

A nuclear reactor control system is provided in a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage. The control system includes dual annular, rotatable reflector rings. There are two reflector rings: an inner reflector ring and an outer reflector ring. The reflectors are concentrically assembled, surround the reactor core, and each reflector ring includes a plurality of openings. The openings in each ring are capable of being aligned or non-aligned with each other. Independent driving means for each of the annular reflector rings is provided so that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core.

Nuclear criticality safety staff training and qualifications at Los Alamos National Laboratory

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

Monahan, S.P.; McLaughlin, T.P.

1997-05-01

Operations involving significant quantities of fissile material have been conducted at Los Alamos National Laboratory continuously since 1943. Until the advent of the Laboratory`s Nuclear Criticality Safety Committee (NCSC) in 1957, line management had sole responsibility for controlling criticality risks. From 1957 until 1961, the NCSC was the Laboratory body which promulgated policy guidance as well as some technical guidance for specific operations. In 1961 the Laboratory created the position of Nuclear Criticality Safety Office (in addition to the NCSC). In 1980, Laboratory management moved the Criticality Safety Officer (and one other LACEF staff member who, by that time, wasmore » also working nearly full-time on criticality safety issues) into the Health Division office. Later that same year the Criticality Safety Group, H-6 (at that time) was created within H-Division, and staffed by these two individuals. The training and education of these individuals in the art of criticality safety was almost entirely self-regulated, depending heavily on technical interactions between each other, as well as NCSC, LACEF, operations, other facility, and broader criticality safety community personnel. Although the Los Alamos criticality safety group has grown both in size and formality of operations since 1980, the basic philosophy that a criticality specialist must be developed through mentoring and self motivation remains the same. Formally, this philosophy has been captured in an internal policy, document ``Conduct of Business in the Nuclear Criticality Safety Group.`` There are no short cuts or substitutes in the development of a criticality safety specialist. A person must have a self-motivated personality, excellent communications skills, a thorough understanding of the principals of neutron physics, a safety-conscious and helpful attitude, a good perspective of real risk, as well as a detailed understanding of process operations and credible upsets.« less

Neural Network Based Intrusion Detection System for Critical Infrastructures

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

Todd Vollmer; Ondrej Linda; Milos Manic

2009-07-01

Resiliency and security in control systems such as SCADA and Nuclear plant’s in today’s world of hackers and malware are a relevant concern. Computer systems used within critical infrastructures to control physical functions are not immune to the threat of cyber attacks and may be potentially vulnerable. Tailoring an intrusion detection system to the specifics of critical infrastructures can significantly improve the security of such systems. The IDS-NNM – Intrusion Detection System using Neural Network based Modeling, is presented in this paper. The main contributions of this work are: 1) the use and analyses of real network data (data recordedmore » from an existing critical infrastructure); 2) the development of a specific window based feature extraction technique; 3) the construction of training dataset using randomly generated intrusion vectors; 4) the use of a combination of two neural network learning algorithms – the Error-Back Propagation and Levenberg-Marquardt, for normal behavior modeling. The presented algorithm was evaluated on previously unseen network data. The IDS-NNM algorithm proved to be capable of capturing all intrusion attempts presented in the network communication while not generating any false alerts.« less

Estimated critical conditions for UF{sub 4}-oil systems in fully oil-reflected spherical geometry

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

Plaster, M.J.

Paraffinic oil has been exposed to UF{sub 6} gas in seal exhaust pumps and cascade equipment at the Portsmouth Gaseous Diffusion Plant. The resulting mixture is more nuclearly reactive than mixtures of UO{sub 2}F{sub 2} and H{sub 2}O and is not bounded by the subcritical mass limits presented in several nuclear criticality safety guides. The purpose of this analysis is to determine several critical parameters; specifically, (1) k{sub {infinity}} and the critical mass for several enrichments and moderation levels and (2) the mass limits for these mixtures. The estimated critical masses for the UF{sub 4}-oil systems are smaller than formore » the UO{sub 2}F{sub 2}-H{sub 2}O systems. The suggested mass limits for the UF{sub 4}-oil systems are 0.240, 0.280, 0.350, 0.430, and 0.670, and 1.170 kg {sup 235}U for enrichments of 100, 50, 20, 10, 5, and 3 wt.% {sup 235}U respectively.« less

10 CFR 72.74 - Reports of accidental criticality or loss of special nuclear material.

Code of Federal Regulations, 2014 CFR

2014-01-01

... nuclear material. 72.74 Section 72.74 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR... accidental criticality or loss of special nuclear material. (a) Each licensee shall notify the NRC Operations...

10 CFR 72.74 - Reports of accidental criticality or loss of special nuclear material.

Code of Federal Regulations, 2013 CFR

2013-01-01

... nuclear material. 72.74 Section 72.74 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR... accidental criticality or loss of special nuclear material. (a) Each licensee shall notify the NRC Operations...

10 CFR 72.74 - Reports of accidental criticality or loss of special nuclear material.

Code of Federal Regulations, 2010 CFR

2010-01-01

... nuclear material. 72.74 Section 72.74 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR... accidental criticality or loss of special nuclear material. (a) Each licensee shall notify the NRC Operations...

10 CFR 72.74 - Reports of accidental criticality or loss of special nuclear material.

Code of Federal Regulations, 2012 CFR

2012-01-01

... nuclear material. 72.74 Section 72.74 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR... accidental criticality or loss of special nuclear material. (a) Each licensee shall notify the NRC Operations...

10 CFR 72.74 - Reports of accidental criticality or loss of special nuclear material.

Code of Federal Regulations, 2011 CFR

2011-01-01

... nuclear material. 72.74 Section 72.74 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSING REQUIREMENTS FOR THE INDEPENDENT STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR... accidental criticality or loss of special nuclear material. (a) Each licensee shall notify the NRC Operations...

Nuclear criticality safety assessment of the low level radioactive waste disposal facility trenches

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

Kahook, S.D.

1994-04-01

Results of the analyses performed to evaluate the possibility of nuclear criticality in the Low Level Radioactive Waste Disposal Facility (LLRWDF) trenches are documented in this report. The studies presented in this document are limited to assessment of the possibility of criticality due to existing conditions in the LLRWDF. This document does not propose nor set limits for enriched uranium (EU) burial in the LLRWDF and is not a nuclear criticality safety evaluation nor analysis. The calculations presented in the report are Level 2 calculations as defined by the E7 Procedure 2.31, Engineering Calculations.

FRENDY: A new nuclear data processing system being developed at JAEA

NASA Astrophysics Data System (ADS)

Tada, Kenichi; Nagaya, Yasunobu; Kunieda, Satoshi; Suyama, Kenya; Fukahori, Tokio

2017-09-01

JAEA has provided an evaluated nuclear data library JENDL and nuclear application codes such as MARBLE, SRAC, MVP and PHITS. These domestic codes have been widely used in many universities and industrial companies in Japan. However, we sometimes find problems in imported processing systems and need to revise them when the new JENDL is released. To overcome such problems and immediately process the nuclear data when it is released, JAEA started developing a new nuclear data processing system, FRENDY in 2013. This paper describes the outline of the development of FRENDY and both its capabilities and performances by the analyses of criticality experiments. The verification results indicate that FRENDY properly generates ACE files.

Test Facilities and Experience on Space Nuclear System Developments at the Kurchatov Institute

NASA Astrophysics Data System (ADS)

Ponomarev-Stepnoi, Nikolai N.; Garin, Vladimir P.; Glushkov, Evgeny S.; Kompaniets, George V.; Kukharkin, Nikolai E.; Madeev, Vicktor G.; Papin, Vladimir K.; Polyakov, Dmitry N.; Stepennov, Boris S.; Tchuniyaev, Yevgeny I.; Tikhonov, Lev Ya.; Uksusov, Yevgeny I.

2004-02-01

The complexity of space fission systems and rigidity of requirement on minimization of weight and dimension characteristics along with the wish to decrease expenditures on their development demand implementation of experimental works which results shall be used in designing, safety substantiation, and licensing procedures. Experimental facilities are intended to solve the following tasks: obtainment of benchmark data for computer code validations, substantiation of design solutions when computational efforts are too expensive, quality control in a production process, and ``iron'' substantiation of criticality safety design solutions for licensing and public relations. The NARCISS and ISKRA critical facilities and unique ORM facility on shielding investigations at the operating OR nuclear research reactor were created in the Kurchatov Institute to solve the mentioned tasks. The range of activities performed at these facilities within the implementation of the previous Russian nuclear power system programs is briefly described in the paper. This experience shall be analyzed in terms of methodological approach to development of future space nuclear systems (this analysis is beyond this paper). Because of the availability of these facilities for experiments, the brief description of their critical assemblies and characteristics is given in this paper.

A neutron dosemeter for nuclear criticality accidents.

PubMed

d'Errico, F; Curzio, G; Ciolini, R; Del Gratta, A; Nath, R

2004-01-01

A neutron dosemeter which offers instant read-out has been developed for nuclear criticality accidents. The system is based on gels containing emulsions of superheated dichlorodifluoromethane droplets, which vaporise into bubbles upon neutron irradiation. The expansion of these bubbles displaces an equivalent volume of gel into a graduated pipette, providing an immediate measure of the dose. Instant read-out is achieved using an array of transmissive optical sensors which consist of coupled LED emitters and phototransistor receivers. When the gel displaced in the pipette crosses the sensing region of the photomicrosensors, it generates a signal collected on a computer through a dedicated acquisition board. The performance of the device was tested during the 2002 International Accident Dosimetry Intercomparison in Valduc, France. The dosemeter was able to follow the initial dose gradient of a simulated accident, providing accurate values of neutron kerma; however, the emulsion was rapidly depleted of all its drops. A model of the depletion effects was developed and it indicates that an adequate dynamic range of the dose response can be achieved by using emulsions of smaller droplets.

Supercritical Brayton Cycle Nuclear Power System Concepts

NASA Astrophysics Data System (ADS)

Wright, Steven A.

2007-01-01

Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

Investigation of criticality safety control infraction data at a nuclear facility

DOE PAGES

Cournoyer, Michael E.; Merhege, James F.; Costa, David A.; ...

2014-10-27

Chemical and metallurgical operations involving plutonium and other nuclear materials account for most activities performed at the LANL's Plutonium Facility (PF-4). The presence of large quantities of fissile materials in numerous forms at PF-4 makes it necessary to maintain an active criticality safety program. The LANL Nuclear Criticality Safety (NCS) Program provides guidance to enable efficient operations while ensuring prevention of criticality accidents in the handling, storing, processing and transportation of fissionable material at PF-4. In order to achieve and sustain lower criticality safety control infraction (CSCI) rates, PF-4 operations are continuously improved, through the use of Lean Manufacturing andmore » Six Sigma (LSS) business practices. Employing LSS, statistically significant variations (trends) can be identified in PF-4 CSCI reports. In this study, trends have been identified in the NCS Program using the NCS Database. An output metric has been developed that measures ADPSM Management progress toward meeting its NCS objectives and goals. Using a Pareto Chart, the primary CSCI attributes have been determined in order of those requiring the most management support. Data generated from analysis of CSCI data help identify and reduce number of corresponding attributes. In-field monitoring of CSCI's contribute to an organization's scientific and technological excellence by providing information that can be used to improve criticality safety operation safety. This increases technical knowledge and augments operational safety.« less

University education and nuclear criticality safety professionals

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

Wilson, R.E.; Stachowiak, R.V.; Knief, R.A.

1996-12-31

The problem of developing a productive criticality safety specialist at a nuclear fuel facility has long been with us. The normal practice is to hire a recent undergraduate or graduate degree recipient and invest at least a decade in on-the-job training. In the early 1980s, the U.S. Department of Energy (DOE) developed a model intern program in an attempt to speed up the process. The program involved working at assigned projects for extended periods at a working critical mass laboratory, a methods development group, and a fuel cycle facility. This never gained support as it involved extended time away frommore » the job. At the Rocky Flats Environmental Technology Site, the training method is currently the traditional one involving extensive experience. The flaw is that the criticality safety staff turnover has been such that few individuals continue for the decade some consider necessary for maturity in the discipline. To maintain quality evaluations and controls as well as interpretation decisions, extensive group review is used. This has proved costly to the site and professionally unsatisfying to the current staff. The site contractor has proposed a training program to remedy the basic problem.« less

Sensitivity-Uncertainty Based Nuclear Criticality Safety Validation

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

Brown, Forrest B.

2016-09-20

These are slides from a seminar given to the University of Mexico Nuclear Engineering Department. Whisper is a statistical analysis package developed to support nuclear criticality safety validation. It uses the sensitivity profile data for an application as computed by MCNP6 along with covariance files for the nuclear data to determine a baseline upper-subcritical-limit for the application. Whisper and its associated benchmark files are developed and maintained as part of MCNP6, and will be distributed with all future releases of MCNP6. Although sensitivity-uncertainty methods for NCS validation have been under development for 20 years, continuous-energy Monte Carlo codes such asmore » MCNP could not determine the required adjoint-weighted tallies for sensitivity profiles. The recent introduction of the iterated fission probability method into MCNP led to the rapid development of sensitivity analysis capabilities for MCNP6 and the development of Whisper. Sensitivity-uncertainty based methods represent the future for NCS validation – making full use of today’s computer power to codify past approaches based largely on expert judgment. Validation results are defensible, auditable, and repeatable as needed with different assumptions and process models. The new methods can supplement, support, and extend traditional validation approaches.« less

Y-12 PLANT NUCLEAR SAFETY HANDBOOK

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

Wachter, J.W. ed.; Bailey, M.L.; Cagle, T.J.

1963-03-27

Information needed to solve nuclear safety problems is condensed into a reference book for use by persons familiar with the field. Included are a glossary of terms; useful tables; nuclear constants; criticality calculations; basic nuclear safety limits; solution geometries and critical values; metal critical values; criticality values for intermediate, heterogeneous, and interacting systems; miscellaneous and related information; and report number, author, and subject indexes. (C.H.)

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.;

Dual annular rotating [open quotes]windowed[close quotes] nuclear reflector reactor control system

DOEpatents

Jacox, M.G.; Drexler, R.L.; Hunt, R.N.M.; Lake, J.A.

1994-03-29

A nuclear reactor control system is provided in a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage. The control system includes dual annular, rotatable reflector rings. There are two reflector rings: an inner reflector ring and an outer reflector ring. The reflectors are concentrically assembled, surround the reactor core, and each reflector ring includes a plurality of openings. The openings in each ring are capable of being aligned or non-aligned with each other. Independent driving means for each of the annular reflector rings is provided so that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core. 4 figures.

Aluminum Data Measurements and Evaluation for Criticality Safety Applications

NASA Astrophysics Data System (ADS)

Leal, L. C.; Guber, K. H.; Spencer, R. R.; Derrien, H.; Wright, R. Q.

2002-12-01

The Defense Nuclear Facility Safety Board (DNFSB) Recommendation 93-2 motivated the US Department of Energy (DOE) to develop a comprehensive criticality safety program to maintain and to predict the criticality of systems throughout the DOE complex. To implement the response to the DNFSB Recommendation 93-2, a Nuclear Criticality Safety Program (NCSP) was created including the following tasks: Critical Experiments, Criticality Benchmarks, Training, Analytical Methods, and Nuclear Data. The Nuclear Data portion of the NCSP consists of a variety of differential measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) at the Oak Ridge National Laboratory (ORNL), data analysis and evaluation using the generalized least-squares fitting code SAMMY in the resolved, unresolved, and high energy ranges, and the development and benchmark testing of complete evaluations for a nuclide for inclusion into the Evaluated Nuclear Data File (ENDF/B). This paper outlines the work performed at ORNL to measure, evaluate, and test the nuclear data for aluminum for applications in criticality safety problems.

A simple model for the critical mass of a nuclear weapon

NASA Astrophysics Data System (ADS)

Reed, B. Cameron

2018-07-01

A probability-based model for estimating the critical mass of a fissile isotope is developed. The model requires introducing some concepts from nuclear physics and incorporating some approximations, but gives results correct to about a factor of two for uranium-235 and plutonium-239.

Used Nuclear Fuel-Storage, Transportation & Disposal Analysis Resource and Data System (UNF-ST&DARDS)

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

Banerjee, Kaushik; Clarity, Justin B; Cumberland, Riley M

This will be licensed via RSICC. A new, integrated data and analysis system has been designed to simplify and automate the performance of accurate and efficient evaluations for characterizing the input to the overall nuclear waste management system -UNF-Storage, Transportation & Disposal Analysis Resource and Data System (UNF-ST&DARDS). A relational database within UNF-ST&DARDS provides a standard means by which UNF-ST&DARDS can succinctly store and retrieve modeling and simulation (M&S) parameters for specific spent nuclear fuel analysis. A library of various analysis model templates provides the ability to communicate the various set of M&S parameters to the most appropriate M&S application.more » Interactive visualization capabilities facilitate data analysis and results interpretation. UNF-ST&DARDS current analysis capabilities include (1) assembly-specific depletion and decay, (2) and spent nuclear fuel cask-specific criticality and shielding. Currently, UNF-ST&DARDS uses SCALE nuclear analysis code system for performing nuclear analysis.« less

Criticality Safety Evaluation for the TACS at DAF

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

Percher, C. M.; Heinrichs, D. P.

2011-06-10

Hands-on experimental training in the physical behavior of multiplying systems is one of ten key areas of training required for practitioners to become qualified in the discipline of criticality safety as identified in DOE-STD-1135-99, Guidance for Nuclear Criticality Safety Engineer Training and Qualification. This document is a criticality safety evaluation of the training activities and operations associated with HS-3201-P, Nuclear Criticality 4-Day Training Course (Practical). This course was designed to also address the training needs of nuclear criticality safety professionals under the auspices of the NNSA Nuclear Criticality Safety Program1. The hands-on, or laboratory, portion of the course will utilizemore » the Training Assembly for Criticality Safety (TACS) and will be conducted in the Device Assembly Facility (DAF) at the Nevada Nuclear Security Site (NNSS). The training activities will be conducted by Lawrence Livermore National Laboratory following the requirements of an Integrated Work Sheet (IWS) and associated Safety Plan. Students will be allowed to handle the fissile material under the supervision of an LLNL Certified Fissile Material Handler.« less

Influence of flow constraints on the properties of the critical endpoint of symmetric nuclear matter

NASA Astrophysics Data System (ADS)

Ivanytskyi, A. I.; Bugaev, K. A.; Sagun, V. V.; Bravina, L. V.; Zabrodin, E. E.

2018-06-01

We propose a novel family of equations of state for symmetric nuclear matter based on the induced surface tension concept for the hard-core repulsion. It is shown that having only four adjustable parameters the suggested equations of state can, simultaneously, reproduce not only the main properties of the nuclear matter ground state, but the proton flow constraint up its maximal particle number densities. Varying the model parameters we carefully examine the range of values of incompressibility constant of normal nuclear matter and its critical temperature, which are consistent with the proton flow constraint. This analysis allows us to show that the physically most justified value of nuclear matter critical temperature is 15.5-18 MeV, the incompressibility constant is 270-315 MeV and the hard-core radius of nucleons is less than 0.4 fm.

Critical Nuclear Charge for Two-electron Atoms

NASA Astrophysics Data System (ADS)

Estienne, C. S.; Drake, G. W. F.

2014-05-01

There has been a recent revival of interest in the critical nuclear charge Zc that is just sufficient to bind a nucleus of charge Z and two electrons in the 1s21 S ground state. It is conjectured that the inverse of critical charge is related to the radius of convergence 1 /Z* for a 1 / Z expansion of the energy of the form E (Z) =Z2 (E0 +E1 / Z +E2 /Z2 + ⋯) . We have performed high precision variational calculations in Hylleraas coordinates, using the double basis set method, for values of Z very close to Zc, with basis sets containing up to 2809 terms (Ω = 24). Our preliminary result is Zc = 0 . 911 028 224 077 260 (15) , corresponding to 1 /Zc = 1 . 097 660 833 738 555 (18) . Well-defined eigenvalues continue to appear for Z

Hydrothermal mineralising systems as critical systems

NASA Astrophysics Data System (ADS)

Hobbs, Bruce

2015-04-01

Hydrothermal mineralising systems as critical systems. Bruce E Hobbs1,2, Alison Ord1 and Mark A. Munro1. 1. Centre for Exploration Targeting, The University of Western Australia, M006, 35 Stirling Highway, Crawley, WA 6009, Australia. 2. CSIRO Earth and Resource Engineering, Bentley, WA, Australia Hydrothermal mineralising systems are presented as large, open chemical reactors held far from equilibrium during their life-time by the influx of heat, fluid and dissolved chemical species. As such they are nonlinear dynamical systems and need to be analysed using the tools that have been developed for such systems. Hydrothermal systems undergo a number of transitions during their evolution and this paper focuses on methods for characterising these transitions in a quantitative manner and establishing whether they resemble first or second (critical) phase transitions or whether they have some other kind of nature. Critical phase transitions are characterised by long range correlations for some parameter characteristic of the system, power-law probability distributions so that there is no characteristic length scale and a high sensitivity to perturbations; as one approaches criticality, characteristic parameters for the system scale in a power law manner with distance from the critical point. The transitions undergone in mineralised hydrothermal systems are: (i) widespread, non-localised mineral alteration involving exothermic mineral reactions that produce hydrous silicate phases, carbonates and iron-oxides, (ii) strongly localised veining, brecciation and/or stock-work formation, (iii) a series of endothermic mineral reactions involving the formation of non-hydrous silicates, sulphides and metals such as gold, (iv) multiple repetitions of transitions (ii) and (iii). We have quantified aspects of these transitions in gold deposits from the Yilgarn craton of Western Australia using wavelet transforms. This technique is convenient and fast. It enables one to establish if

Potential civil mission applications for space nuclear power systems

NASA Technical Reports Server (NTRS)

Ambrus, J. H.; Beatty, R. G. G.

1985-01-01

It is pointed out that the energy needs of spacecraft over the last 25 years have been met by photovoltaic arrays with batteries, primary fuel cells, and radioisotope thermoelectric generators (RTG). However, it might be difficult to satisfy energy requirements for the next generation of space missions with the currently used energy sources. Applications studies have emphasized the need for a lighter, cheaper, and more compact high-energy source than the scaling up of current technologies would permit. These requirements could be satisfied by a nuclear reactor power system. The joint NASA/DOD/DOE SP-100 program is to explore and evaluate this option. Critical elements of the technology are also to be developed, taking into account space reactor systems of the 100 kW class. The present paper is concerned with some of the civil mission categories and concepts which are enabled or significantly enhanced by the performance characteristics of a nuclear reactor energy system.

75 FR 11918 - Hewlett Pachard Company, Business Critical Systems, Mission Critical Business Software Division...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-12

... Pachard Company, Business Critical Systems, Mission Critical Business Software Division, Openvms Operating... Business Software Division, Openvms Operating System Development Group, Including an Employee Operating Out... Company, Business Critical Systems, Mission Critical Business Software Division, OpenVMS Operating System...

Final Technical Report on Quantifying Dependability Attributes of Software Based Safety Critical Instrumentation and Control Systems in Nuclear Power Plants

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

Smidts, Carol; Huang, Funqun; Li, Boyuan

With the current transition from analog to digital instrumentation and control systems in nuclear power plants, the number and variety of software-based systems have significantly increased. The sophisticated nature and increasing complexity of software raises trust in these systems as a significant challenge. The trust placed in a software system is typically termed software dependability. Software dependability analysis faces uncommon challenges since software systems’ characteristics differ from those of hardware systems. The lack of systematic science-based methods for quantifying the dependability attributes in software-based instrumentation as well as control systems in safety critical applications has proved itself to be amore » significant inhibitor to the expanded use of modern digital technology in the nuclear industry. Dependability refers to the ability of a system to deliver a service that can be trusted. Dependability is commonly considered as a general concept that encompasses different attributes, e.g., reliability, safety, security, availability and maintainability. Dependability research has progressed significantly over the last few decades. For example, various assessment models and/or design approaches have been proposed for software reliability, software availability and software maintainability. Advances have also been made to integrate multiple dependability attributes, e.g., integrating security with other dependability attributes, measuring availability and maintainability, modeling reliability and availability, quantifying reliability and security, exploring the dependencies between security and safety and developing integrated analysis models. However, there is still a lack of understanding of the dependencies between various dependability attributes as a whole and of how such dependencies are formed. To address the need for quantification and give a more objective basis to the review process -- therefore reducing regulatory

System model development for nuclear thermal propulsion

NASA Technical Reports Server (NTRS)

Walton, James T.; Hannan, Nelson A.; Perkins, Ken R.; Buksa, John H.; Worley, Brian A.; Dobranich, Dean

1992-01-01

A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown, and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, and cost and time required for the technology to reach flight-ready status. Since Oct. 1991, the U.S. Department of Energy (DOE), Department of Defense (DOD), and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. The first level will provide rapid, parameterized calculations of overall system performance. Succeeding computer programs will provide analysis of each component in sufficient detail to guide the design teams and experimental efforts. The computer programs will allow simulation of the entire system to allow prediction of the integrated performance. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review.

DOE/DHS INDUSTRIAL CONTROL SYSTEM CYBER SECURITY PROGRAMS: A MODEL FOR USE IN NUCLEAR FACILITY SAFEGUARDS AND SECURITY

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

Robert S. Anderson; Mark Schanfein; Trond Bjornard

2011-07-01

Many critical infrastructure sectors have been investigating cyber security issues for several years especially with the help of two primary government programs. The U.S. Department of Energy (DOE) National SCADA Test Bed and the U.S. Department of Homeland Security (DHS) Control Systems Security Program have both implemented activities aimed at securing the industrial control systems that operate the North American electric grid along with several other critical infrastructure sectors (ICS). These programs have spent the last seven years working with industry including asset owners, educational institutions, standards and regulating bodies, and control system vendors. The programs common mission is tomore » provide outreach, identification of cyber vulnerabilities to ICS and mitigation strategies to enhance security postures. The success of these programs indicates that a similar approach can be successfully translated into other sectors including nuclear operations, safeguards, and security. The industry regulating bodies have included cyber security requirements and in some cases, have incorporated sets of standards with penalties for non-compliance such as the North American Electric Reliability Corporation Critical Infrastructure Protection standards. These DOE and DHS programs that address security improvements by both suppliers and end users provide an excellent model for nuclear facility personnel concerned with safeguards and security cyber vulnerabilities and countermeasures. It is not a stretch to imagine complete surreptitious collapse of protection against the removal of nuclear material or even initiation of a criticality event as witnessed at Three Mile Island or Chernobyl in a nuclear ICS inadequately protected against the cyber threat.« less

Nuclear Safety for Space Systems

NASA Astrophysics Data System (ADS)

Offiong, Etim

2010-09-01

It is trite, albeit a truism, to say that nuclear power can provide propulsion thrust needed to launch space vehicles and also, to provide electricity for powering on-board systems, especially for missions to the Moon, Mars and other deep space missions. Nuclear Power Sources(NPSs) are known to provide more capabilities than solar power, fuel cells and conventional chemical means. The worry has always been that of safety. The earliest superpowers(US and former Soviet Union) have designed and launched several nuclear-powered systems, with some failures. Nuclear failures and accidents, however little the number, could be far-reaching geographically, and are catastrophic to humans and the environment. Building on the numerous research works on nuclear power on Earth and in space, this paper seeks to bring to bear, issues relating to safety of space systems - spacecrafts, astronauts, Earth environment and extra terrestrial habitats - in the use and application of nuclear power sources. It also introduces a new formal training course in Space Systems Safety.

Nuclear power technology requirements for NASA exploration missions

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.

1990-01-01

It is pointed out that future exploration of the moon and Mars will mandate developments in many areas of technology. In particular, major advances will be required in planet surface power systems. Critical nuclear technology challenges that can enable strategic self-sufficiency, acceptable operational costs, and cost-effective space transportation goals for NASA exploration missions have been identified. Critical technologies for surface power systems include stationary and mobile nuclear reactor and radioisotope heat sources coupled to static and dynamic power conversion devices. These technologies can provide dramatic reductions in mass, leading to operational and transportation cost savings. Critical technologies for space transportation systems include nuclear thermal rocket and nuclear electric propulsion options, which present compelling concepts for significantly reducing mass, cost, or travel time required for Earth-Mars transport.

Critical insights into nuclear collectivity from complementary nuclear spectroscopic methods

NASA Astrophysics Data System (ADS)

Garrett, P. E.; Wood, J. L.; Yates, S. W.

2018-06-01

Low-energy collectivity of nuclei has been, and is being, characterized in a critical manner using data from a variety of spectroscopic methods, including Coulomb excitation, β decay, inelastic scattering of charged and uncharged particles, transfer reactions, etc. In addition to level energies and spins, transition multipolarities and intensities, lifetimes, and nuclear moments are available. The totality of information from these probes must be considered in achieving an accurate vision of the excitations in nuclei and determining the applicability of nuclear models. From these data, major changes in our view of low-energy collectivity in nuclei have emerged; most notable is the demise of the long-held view of low-energy quadrupole collectivity near closed shells as due to vibrations about a spherical equilibrium shape. In this contribution, we focus on the basic predictions of the spherical harmonic vibrator limit of the Bohr Hamiltonian. Properties such as B(E2) values, quadrupole moments, E0 strengths, etc are outlined. Using the predicted properties as a guide, evidence is cited for and against the existence of vibrational states, and especially multi-phonon states, in nuclei that are, or historically were considered to be, spherical or have a nearly spherical shape in their ground state. It is found that very few of the nuclei that were identified in the last major survey seeking nearly spherical harmonic vibrators satisfy the more stringent guidelines presented herein. Details of these fundamental shifts in our view of low-energy collectivity in nuclei are presented.

Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

NASA Technical Reports Server (NTRS)

Taylor, M. F.; Whitmarsh, C. L., Jr.; Sirocky, P. J., Jr.; Iwanczyke, L. C.

1973-01-01

A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

75 FR 5146 - Hewlett Packard Company Business Critical Systems, Mission Critical Business Software Division...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

... Packard Company Business Critical Systems, Mission Critical Business Software Division, OpenVMS Operating... Software Division, OpenVMS Operating System Development Group, Including an Employee Operating Out of the..., Mission Critical Business Software Division, OpenVMS Operating System Development Group, including...

Exploratory study of several advanced nuclear-MHD power plant systems.

NASA Technical Reports Server (NTRS)

Williams, J. R.; Clement, J. D.; Rosa, R. J.; Yang, Y. Y.

1973-01-01

In order for efficient multimegawatt closed cycle nuclear-MHD systems to become practical, long-life gas cooled reactors with exit temperatures of about 2500 K or higher must be developed. Four types of nuclear reactors which have the potential of achieving this goal are the NERVA-type solid core reactor, the colloid core (rotating fluidized bed) reactor, the 'light bulb' gas core reactor, and the 'coaxial flow' gas core reactor. Research programs aimed at developing these reactors have progressed rapidly in recent years so that prototype power reactors could be operating by 1980. Three types of power plant systems which use these reactors have been analyzed to determine the operating characteristics, critical parameters and performance of these power plants. Overall thermal efficiencies as high as 80% are projected, using an MHD turbine-compressor cycle with steam bottoming, and slightly lower efficiencies are projected for an MHD motor-compressor cycle.

Validation Study for Crediting Chlorine in Criticality Analyses for US Spent Nuclear Fuel Disposition

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

Sobes, Vladimir; Scaglione, John M.; Wagner, John C.

2015-01-01

Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allowmore » the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10 -5 k eff). This study investigated the design of a series of critical

NUCLEAR REACTOR CONTROL SYSTEM

DOEpatents

Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

1959-11-01

A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

Manned space flight nuclear system safety. Volume 5: Nuclear System safety guidelines. Part 1: Space base nuclear safety

NASA Technical Reports Server (NTRS)

1972-01-01

The design and operations guidelines and requirements developed in the study of space base nuclear system safety are presented. Guidelines and requirements are presented for the space base subsystems, nuclear hardware (reactor, isotope sources, dynamic generator equipment), experiments, interfacing vehicles, ground support systems, range safety and facilities. Cross indices and references are provided which relate guidelines to each other, and to substantiating data in other volumes. The guidelines are intended for the implementation of nuclear safety related design and operational considerations in future space programs.

Integrated nuclear data utilisation system for innovative reactors.

PubMed

Yamano, N; Hasegawa, A; Kato, K; Igashira, M

2005-01-01

A five-year research and development project on an integrated nuclear data utilisation system was initiated in 2002, for developing innovative nuclear energy systems such as accelerator-driven systems. The integrated nuclear data utilisation system will be constructed as a modular code system, which consists of two sub-systems: the nuclear data search and plotting sub-system, and the nuclear data processing and utilisation sub-system. The system will be operated with a graphical user interface in order to enable easy utilisation through the Internet by both nuclear design engineers and nuclear data evaluators. This paper presents an overview of the integrated nuclear data utilisation system, describes the development of a prototype system to examine the operability of the user interface and discusses specifications of the two sub-systems.

Critical areas: Satellite power systems concepts

NASA Technical Reports Server (NTRS)

1975-01-01

Critical Areas are defined and discussed in the various areas pertinent to satellite power systems. The presentation is grouped into five areas (General, Space Systems, Solar Energy Conversion, Microwave Systems, and Environment/Ecology) with a sixth area (Power Relay) considered separately in an appendix. Areas for Future Consideration as critical areas are discussed in a second appendix.

A high-throughput screening system targeting the nuclear export pathway via the third nuclear export signal of influenza A virus nucleoprotein.

PubMed

Kakisaka, Michinori; Mano, Takafumi; Aida, Yoko

2016-06-02

Two classes of antiviral drugs, M2 channel inhibitors and neuraminidase (NA) inhibitors, are currently approved for the treatment of influenza; however, the development of resistance against these agents limits their efficacy. Therefore, the identification of new targets and the development of new antiviral drugs against influenza are urgently needed. The third nuclear export signal (NES3) of nucleoprotein (NP) is the most important for viral replication among seven NESs encoded by four viral proteins, NP, M1, NS1, and NS2. NP-NES3 is critical for the nuclear export of NP, and targeting NP-NES3 is therefore a promising strategy that may lead to the development of antiviral drugs. However, a high-throughput screening (HTS) system to identify inhibitors of NP nuclear export has not been established. Here, we developed a novel HTS system to evaluate the inhibitory effects of compounds on the nuclear export pathway mediated by NP-NES3 using a MDCK cell line stably expressing NP-NES3 fused to a green fluorescent protein from aequorea coerulescens (AcGFP-NP-NES3) and a cell imaging analyzer. This HTS system was used to screen a 9600-compound library, leading to the identification of several hit compounds with inhibitory activity against the nuclear export of AcGFP-NP-NES3. The present HTS system provides a useful strategy for the identification of inhibitors targeting the nuclear export of NP via its NES3 sequence. Copyright © 2016. Published by Elsevier B.V.

Manned space flight nuclear system safety. Voluem 5: Nuclear system safety guidelines. Part 2: Space shuttle/nuclear payloads safety

NASA Technical Reports Server (NTRS)

1972-01-01

The design and operations guidelines and requirements developed in the study of space shuttle nuclear system transportation are presented. Guidelines and requirements are presented for the shuttle, nuclear payloads (reactor, isotope-Brayton and small isotope sources), ground support systems and facilities. Cross indices and references are provided which relate guidelines to each other, and to substantiating data in other volumes. The guidelines are intended for the implementation of nuclear safety related design and operational considerations in future space programs.

Nuclear Systems Kilopower Overview

NASA Technical Reports Server (NTRS)

Palac, Don; Gibson, Marc; Mason, Lee; Houts, Michael; McClure, Patrick; Robinson, Ross

2016-01-01

The Nuclear Systems Kilopower Project was initiated by NASAs Space Technology Mission Directorate Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Nuclear Systems Kilopower Project consists of two elements. The primary element is the Kilopower Prototype Test, also called the Kilopower Reactor Using Stirling Technology(KRUSTY) Test. This element consists of the development and testing of a fission ground technology demonstrator of a 1 kWe fission power system. A 1 kWe system matches requirements for some robotic precursor exploration systems and future potential deep space science missions, and also allows a nuclear ground technology demonstration in existing nuclear test facilities at low cost. The second element, the Mars Kilopower Scalability Study, consists of the analysis and design of a scaled-up version of the 1 kWe reference concept to 10 kWe for Mars surface power projected requirements, and validation of the applicability of the KRUSTY experiment to key technology challenges for a 10 kWe system. If successful, these two elements will lead to initiation of planning for a technology demonstration of a 10 kWe fission power capability for Mars surface outpost power.

Weld monitor and failure detector for nuclear reactor system

DOEpatents

Sutton, Jr., Harry G.

1987-01-01

Critical but inaccessible welds in a nuclear reactor system are monitored throughout the life of the reactor by providing small aperture means projecting completely through the reactor vessel wall and also through the weld or welds to be monitored. The aperture means is normally sealed from the atmosphere within the reactor. Any incipient failure or cracking of the weld will cause the environment contained within the reactor to pass into the aperture means and thence to the outer surface of the reactor vessel where its presence is readily detected.

Some Challenges in the Design of Human-Automation Interaction for Safety-Critical Systems

NASA Technical Reports Server (NTRS)

Feary, Michael S.; Roth, Emilie

2014-01-01

Increasing amounts of automation are being introduced to safety-critical domains. While the introduction of automation has led to an overall increase in reliability and improved safety, it has also introduced a class of failure modes, and new challenges in risk assessment for the new systems, particularly in the assessment of rare events resulting from complex inter-related factors. Designing successful human-automation systems is challenging, and the challenges go beyond good interface development (e.g., Roth, Malin, & Schreckenghost 1997; Christoffersen & Woods, 2002). Human-automation design is particularly challenging when the underlying automation technology generates behavior that is difficult for the user to anticipate or understand. These challenges have been recognized in several safety-critical domains, and have resulted in increased efforts to develop training, procedures, regulations and guidance material (CAST, 2008, IAEA, 2001, FAA, 2013, ICAO, 2012). This paper points to the continuing need for new methods to describe and characterize the operational environment within which new automation concepts are being presented. We will describe challenges to the successful development and evaluation of human-automation systems in safety-critical domains, and describe some approaches that could be used to address these challenges. We will draw from experience with the aviation, spaceflight and nuclear power domains.

Non-muscle myosin IIB is critical for nuclear translocation during 3D invasion

PubMed Central

Yenepalli, Aishwarya; Denais, Celine Marie; Rape, Andrew; Beach, Jordan R.; Wang, Yu-li; Schiemann, William P.; Baskaran, Harihara; Lammerding, Jan

2015-01-01

Non-muscle myosin II (NMII) is reported to play multiple roles during cell migration and invasion. However, the exact biophysical roles of different NMII isoforms during these processes remain poorly understood. We analyzed the contributions of NMIIA and NMIIB in three-dimensional (3D) migration and in generating the forces required for efficient invasion by mammary gland carcinoma cells. Using traction force microscopy and microfluidic invasion devices, we demonstrated that NMIIA is critical for generating force during active protrusion, and NMIIB plays a major role in applying force on the nucleus to facilitate nuclear translocation through tight spaces. We further demonstrate that the nuclear membrane protein nesprin-2 is a possible linker coupling NMIIB-based force generation to nuclear translocation. Together, these data reveal a central biophysical role for NMIIB in nuclear translocation during 3D invasive migration, a result with relevance not only to cancer metastasis but for 3D migration in other settings such as embryonic cell migration and wound healing. PMID:26261182

Nuclear medicine imaging system

DOEpatents

Bennett, G.W.; Brill, A.B.; Bizais, Y.J.C.; Rowe, R.W.; Zubal, I.G.

1983-03-11

It is an object of this invention to provide a nuclear imaging system having the versatility to do positron annihilation studies, rotating single or opposed camera gamma emission studies, and orthogonal gamma emission studies. It is a further object of this invention to provide an imaging system having the capability for orthogonal dual multipinhole tomography. It is another object of this invention to provide a nuclear imaging system in which all available energy data, as well as patient physiological data, are acquired simultaneously in list mode.

Formulation of a strategy for monitoring control integrity in critical digital control systems

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

1991-01-01

Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

Critical care nursing: Embedded complex systems.

PubMed

Trinier, Ruth; Liske, Lori; Nenadovic, Vera

2016-01-01

Variability in parameters such as heart rate, respiratory rate and blood pressure defines healthy physiology and the ability of the person to adequately respond to stressors. Critically ill patients have lost this variability and require highly specialized nursing care to support life and monitor changes in condition. The critical care environment is a dynamic system through which information flows. The critical care unit is typically designed as a tree structure with generally one attending physician and multiple nurses and allied health care professionals. Information flow through the system allows for identification of deteriorating patient status and timely interventionfor rescue from further deleterious effects. Nurses provide the majority of direct patient care in the critical care setting in 2:1, 1:1 or 1:2 nurse-to-patient ratios. The bedside nurse-critically ill patient relationship represents the primary, real-time feedback loop of information exchange, monitoring and treatment. Variables that enhance information flow through this loop and support timely nursing intervention can improve patient outcomes, while barriers can lead to errors and adverse events. Examining patient information flow in the critical care environment from a dynamic systems perspective provides insights into how nurses deliver effective patient care and prevent adverse events.

YALINA facility a sub-critical Accelerator- Driven System (ADS) for nuclear energy research facility description and an overview of the research program (1997-2008).

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

Gohar, Y.; Smith, D. L.; Nuclear Engineering Division

2010-04-28

The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried outmore » there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at validating codes and computational procedures and at providing a better understanding of the physics and operational behavior of the YALINA facility in particular, and ADS systems in general, during the period 1997-2008.« less

Self-Organized Criticality Systems

NASA Astrophysics Data System (ADS)

Aschwanden, M. J.

2013-07-01

Contents: (1) Introduction - Norma B. Crosby --- (2) Theoretical Models of SOC Systems - Markus J. Aschwanden --- (3) SOC and Fractal Geometry - R. T. James McAteer --- (4) Percolation Models of Self-Organized Critical Phenomena - Alexander V. Milovanov --- (5) Criticality and Self-Organization in Branching Processes: Application to Natural Hazards - Álvaro Corral, Francesc Font-Clos --- (6) Power Laws of Recurrence Networks - Yong Zou, Jobst Heitzig, Jürgen Kurths --- (7) SOC computer simolations - Gunnar Pruessner --- (8) SOC Laboratory Experiments - Gunnar Pruessner --- (9) Self-Organizing Complex Earthquakes: Scaling in Data, Models, and Forecasting - Michael K. Sachs et al. --- (10) Wildfires and the Forest-Fire Model - Stefan Hergarten --- (11) SOC in Landslides - Stefan Hergarten --- (12) SOC and Solar Flares - Paul Charbonneau --- (13) SOC Systems in Astrophysics - Markus J. Aschwanden ---

The development of regulatory expectations for computer-based safety systems for the UK nuclear programme

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

Hughes, P. J.; Westwood, R.N; Mark, R. T.

2006-07-01

The Nuclear Installations Inspectorate (NII) of the UK's Health and Safety Executive (HSE) has completed a review of their Safety Assessment Principles (SAPs) for Nuclear Installations recently. During the period of the SAPs review in 2004-2005 the designers of future UK naval reactor plant were optioneering the control and protection systems that might be implemented. Because there was insufficient regulatory guidance available in the naval sector to support this activity the Defence Nuclear Safety Regulator (DNSR) invited the NII to collaborate with the production of a guidance document that provides clarity of regulatory expectations for the production of safety casesmore » for computer based safety systems. A key part of producing regulatory expectations was identifying the relevant extant standards and sector guidance that reflect good practice. The three principal sources of such good practice were: IAEA Safety Guide NS-G-1.1 (Software for Computer Based Systems Important to Safety in Nuclear Power Plants), European Commission consensus document (Common Position of European Nuclear Regulators for the Licensing of Safety Critical Software for Nuclear Reactors) and IEC nuclear sector standards such as IEC60880. A common understanding has been achieved between the NII and DNSR and regulatory guidance developed which will be used by both NII and DNSR in the assessment of computer-based safety systems and in the further development of more detailed joint technical assessment guidance for both regulatory organisations. (authors)« less

Generation-IV Nuclear Energy Systems

NASA Astrophysics Data System (ADS)

McFarlane, Harold

2008-05-01

Nuclear power technology has evolved through roughly three generations of system designs: a first generation of prototypes and first-of-a-kind units implemented during the period 1950 to 1970; a second generation of industrial power plants built from 1970 to the turn of the century, most of which are still in operation today; and a third generation of evolutionary advanced reactors which began being built by the turn of the 20^th century, usually called Generation III or III+, which incorporate technical lessons learned through more than 12,000 reactor-years of operation. The Generation IV International Forum (GIF) is a cooperative international endeavor to develop advanced nuclear energy systems in response to the social, environmental and economic requirements of the 21^st century. Six Generation IV systems under development by GIF promise to enhance the future contribution and benefits of nuclear energy. All Generation IV systems aim at performance improvement, new applications of nuclear energy, and/or more sustainable approaches to the management of nuclear materials. High-temperature systems offer the possibility of efficient process heat applications and eventually hydrogen production. Enhanced sustainability is achieved primarily through adoption of a closed fuel cycle with reprocessing and recycling of plutonium, uranium and minor actinides using fast reactors. This approach provides significant reduction in waste generation and uranium resource requirements.

Why Mission-Critical Systems Are Critical to the Future of Academic Libraries

ERIC Educational Resources Information Center

Oberlander, Cyril

2012-01-01

A mission-critical system is one that is so intertwined with the operation of an organization that the organization can scarcely function without it. Just as in corporations, mission-critical library systems offer the capability to unlock talent and time. They are essential to the transformation of higher education and the learning environment. A…

A Review of Tribomaterial Technology for Space Nuclear Power Systems

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.

2007-01-01

The National Aeronautics and Space Administration (NASA) has recently proposed a nuclear closed-cycle electric power conversion system for generation of 100-kW of electrical power for space exploration missions. A critical issue is the tribological performance of sliding components within the power conversion unit that will be exposed to neutron radiation. This paper presents a review of the main considerations that have been made in the selection of solid lubricants for similar applications in the past as well as a recommendations for continuing development of the technology.

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).

Spent nuclear fuel dry transfer system

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

Stewart, L.; Agace, S.

The U.S. Department of Energy is currently engaged in a cooperative program with the Electric Power Research Institute (EPRI) to design a spent nuclear fuel dry transfer system (DTS). The system will enable the transfer of individual spent nuclear fuel assemblies between a conventional top loading cask and multi-purpose canister in a shielded overpack, or accommodate spent nuclear fuel transfers between two conventional casks.

A Cyber Security Self-Assessment Method for Nuclear Power Plants

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

Glantz, Clifford S.; Coles, Garill A.; Bass, Robert B.

2004-11-01

A cyber security self-assessment method (the Method) has been developed by Pacific Northwest National Laboratory. The development of the Method was sponsored and directed by the U.S. Nuclear Regulatory Commission. Members of the Nuclear Energy Institute Cyber Security Task Force also played a substantial role in developing the Method. The Method's structured approach guides nuclear power plants in scrutinizing their digital systems, assessing the potential consequences to the plant of a cyber exploitation, identifying vulnerabilities, estimating cyber security risks, and adopting cost-effective protective measures. The focus of the Method is on critical digital assets. A critical digital asset is amore » digital device or system that plays a role in the operation, maintenance, or proper functioning of a critical system (i.e., a plant system that can impact safety, security, or emergency preparedness). A critical digital asset may have a direct or indirect connection to a critical system. Direct connections include both wired and wireless communication pathways. Indirect connections include sneaker-net pathways by which software or data are manually transferred from one digital device to another. An indirect connection also may involve the use of instructions or data stored on a critical digital asset to make adjustments to a critical system. The cyber security self-assessment begins with the formation of an assessment team, and is followed by a six-stage process.« less

Ship-Based Nuclear Energy Systems for Accelerating Developing World Socioeconomic Advance

NASA Astrophysics Data System (ADS)

Petroski, Robert; Wood, Lowell

2014-07-01

those having intermittency characteristics. Consideration is directed to the relative economics of ship-based and land-based nuclear power stations, and the costs of undersea transmission lines and suitable moorings are discussed, as well as station-maintenance expenses. Potential cost savings from reduced seismic engineering, serialized production, and reduction/elimination of site-specific engineering are determined to be likely to enable large floating nuclear energy systems to be deployed at both significantly lower cost and with lower financial risk than comparable land-based systems. Such plants thus appear to be a compelling option for agilely supplying flexible energy-flows to developing regions, especially as they allow major components of the overhead costs and time-delays of large-scale energy systems to be avoided. Finally, the critical set of issues related to appropriately regulating and insuring floating nuclear power plants designed for export is examined. Approaches to ensuring adequate safety and environmental stewardship while properly allocating risks between system owners/operators and host countries of floating nuclear energy systems are discussed, along with possible pathways toward implementation. Robustness of exemplary nuclear energy systems from all forms of misuse, including materials diversion, is noted, thus ensuring suitability for complications-free, non-discriminatory global deployments. Availability of abundant, low-cost nuclear energy which can flexibly satisfy the full spectrum of energy demands of the economies of developing countries will inevitably result in significantly earlier and more environmentally-sound energy intensification of societies enjoying such advantages. This will help spur autocatalytic gains in human well-being and economic development rates similar to those seen in the developed world during the last two-thirds of a century, while avoiding some of the undesirable sideeffects often associated with those gains

Impact of nuclear data uncertainty on safety calculations for spent nuclear fuel geological disposal

NASA Astrophysics Data System (ADS)

Herrero, J. J.; Rochman, D.; Leray, O.; Vasiliev, A.; Pecchia, M.; Ferroukhi, H.; Caruso, S.

2017-09-01

In the design of a spent nuclear fuel disposal system, one necessary condition is to show that the configuration remains subcritical at time of emplacement but also during long periods covering up to 1,000,000 years. In the context of criticality safety applying burn-up credit, k-eff eigenvalue calculations are affected by nuclear data uncertainty mainly in the burnup calculations simulating reactor operation and in the criticality calculation for the disposal canister loaded with the spent fuel assemblies. The impact of nuclear data uncertainty should be included in the k-eff value estimation to enforce safety. Estimations of the uncertainty in the discharge compositions from the CASMO5 burn-up calculation phase are employed in the final MCNP6 criticality computations for the intact canister configuration; in between, SERPENT2 is employed to get the spent fuel composition along the decay periods. In this paper, nuclear data uncertainty was propagated by Monte Carlo sampling in the burn-up, decay and criticality calculation phases and representative values for fuel operated in a Swiss PWR plant will be presented as an estimation of its impact.

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.

The 9-11 Commission's invitation to imagine: a pathophysiology-based approach to critical care of nuclear explosion victims.

PubMed

Manthous, Constantine A; Jackson, William L

2007-03-01

The successful management of mass casualties arising from detonation of a nuclear device (NDD) would require significant preparation at all levels of the healthcare system. This article briefly outlines previously published models of destruction and casualties, details approaches to on-site triage and medical evacuation, and offers pathophysiology-based suggestions for treatment of the critically injured. Documentation from previous bomb blasts and nuclear accidents is reviewed to assist in forecasting needs of both systems and patients in the event of an NDD in a major metropolitan area. This review extracts data from previously published models of destruction and casualties projected from an NDD, the primary literature detailing observations of patients' pathophysiology following NDDs in Japan and relevant nuclear accidents, and available contemporary resources for first responders and healthcare providers. The blast and radiation exposures that accompany an NDD will significantly affect local and regional public resources. Morbidity and mortality likely to arise in the setting of dose-dependent organ dysfunction may be minimized by rigorous a priori planning/training for field triage decisions, coordination of medical and civil responses to effect rapid responses and medical evacuation routes, radiation-specific interventions, and modern intensive care. Although the responses of emergency and healthcare systems following NDD will vary depending on the exact mechanism, magnitude, and location of the event, dose exposures and individual pathophysiology evolution are reasonably predictable. Triage decisions, resource requirements, and bedside therapeutic plans can be evidence-based and can be developed rapidly with appropriate preparation and planning.

A reference model for model-based design of critical infrastructure protection systems

NASA Astrophysics Data System (ADS)

Shin, Young Don; Park, Cheol Young; Lee, Jae-Chon

2015-05-01

Today's war field environment is getting versatile as the activities of unconventional wars such as terrorist attacks and cyber-attacks have noticeably increased lately. The damage caused by such unconventional wars has also turned out to be serious particularly if targets are critical infrastructures that are constructed in support of banking and finance, transportation, power, information and communication, government, and so on. The critical infrastructures are usually interconnected to each other and thus are very vulnerable to attack. As such, to ensure the security of critical infrastructures is very important and thus the concept of critical infrastructure protection (CIP) has come. The program to realize the CIP at national level becomes the form of statute in each country. On the other hand, it is also needed to protect each individual critical infrastructure. The objective of this paper is to study on an effort to do so, which can be called the CIP system (CIPS). There could be a variety of ways to design CIPS's. Instead of considering the design of each individual CIPS, a reference model-based approach is taken in this paper. The reference model represents the design of all the CIPS's that have many design elements in common. In addition, the development of the reference model is also carried out using a variety of model diagrams. The modeling language used therein is the systems modeling language (SysML), which was developed and is managed by Object Management Group (OMG) and a de facto standard. Using SysML, the structure and operational concept of the reference model are designed to fulfil the goal of CIPS's, resulting in the block definition and activity diagrams. As a case study, the operational scenario of the nuclear power plant while being attacked by terrorists is studied using the reference model. The effectiveness of the results is also analyzed using multiple analysis models. It is thus expected that the approach taken here has some merits

Nuclear power propulsion system for spacecraft

NASA Astrophysics Data System (ADS)

Koroteev, A. S.; Oshev, Yu. A.; Popov, S. A.; Karevsky, A. V.; Solodukhin, A. Ye.; Zakharenkov, L. E.; Semenkin, A. V.

2015-12-01

The proposed designs of high-power space tugs that utilize solar or nuclear energy to power an electric jet engine are reviewed. The conceptual design of a nuclear power propulsion system (NPPS) is described; its structural diagram, gas circuit, and electric diagram are discussed. The NPPS incorporates a nuclear reactor, a thermal-to-electric energy conversion system, a system for the conversion and distribution of electric energy, and an electric propulsion system. Two criterion parameters were chosen in the considered NPPS design: the temperature of gaseous working medium at the nuclear reactor outlet and the rotor speed of turboalternators. The maintenance of these parameters at a given level guarantees that the needed electric voltage is generated and allows for power mode control. The processes of startup/shutdown and increasing/reducing the power, the principles of distribution of electric energy over loads, and the probable emergencies for the proposed NPPS design are discussed.

Bad Actors Criticality Assessment for Pipeline system

NASA Astrophysics Data System (ADS)

Nasir, Meseret; Chong, Kit wee; Osman, Sabtuni; Siaw Khur, Wee

2015-04-01

Failure of a pipeline system could bring huge economic loss. In order to mitigate such catastrophic loss, it is required to evaluate and rank the impact of each bad actor of the pipeline system. In this study, bad actors are known as the root causes or any potential factor leading to the system downtime. Fault Tree Analysis (FTA) is used to analyze the probability of occurrence for each bad actor. Bimbaum's Importance and criticality measure (BICM) is also employed to rank the impact of each bad actor on the pipeline system failure. The results demonstrate that internal corrosion; external corrosion and construction damage are critical and highly contribute to the pipeline system failure with 48.0%, 12.4% and 6.0% respectively. Thus, a minor improvement in internal corrosion; external corrosion and construction damage would bring significant changes in the pipeline system performance and reliability. These results could also be useful to develop efficient maintenance strategy by identifying the critical bad actors.

Manned space flight nuclear system safety. Volume 4: Space shuttle nuclear system transportation. Part 1: Space shuttle nuclear safety

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis of the nuclear safety aspects (design and operational considerations) in the transport of nuclear payloads to and from earth orbit by the space shuttle is presented. Three representative nuclear payloads used in the study were: (1) the zirconium hydride reactor Brayton power module, (2) the large isotope Brayton power system and (3) small isotopic heat sources which can be a part of an upper stage or part of a logistics module. Reference data on the space shuttle and nuclear payloads are presented in an appendix. Safety oriented design and operational requirements were identified to integrate the nuclear payloads in the shuttle mission. Contingency situations were discussed and operations and design features were recommended to minimize the nuclear hazards. The study indicates the safety, design and operational advantages in the use of a nuclear payload transfer module. The transfer module can provide many of the safety related support functions (blast and fragmentation protection, environmental control, payload ejection) minimizing the direct impact on the shuttle.

Criticality Calculations with MCNP6 - Practical Lectures

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

Brown, Forrest B.; Rising, Michael Evan; Alwin, Jennifer Louise

2016-11-29

These slides are used to teach MCNP (Monte Carlo N-Particle) usage to nuclear criticality safety analysts. The following are the lecture topics: course information, introduction, MCNP basics, criticality calculations, advanced geometry, tallies, adjoint-weighted tallies and sensitivities, physics and nuclear data, parameter studies, NCS validation I, NCS validation II, NCS validation III, case study 1 - solution tanks, case study 2 - fuel vault, case study 3 - B&W core, case study 4 - simple TRIGA, case study 5 - fissile mat. vault, criticality accident alarm systems. After completion of this course, you should be able to: Develop an input modelmore » for MCNP; Describe how cross section data impact Monte Carlo and deterministic codes; Describe the importance of validation of computer codes and how it is accomplished; Describe the methodology supporting Monte Carlo codes and deterministic codes; Describe pitfalls of Monte Carlo calculations; Discuss the strengths and weaknesses of Monte Carlo and Discrete Ordinants codes; The diffusion theory model is not strictly valid for treating fissile systems in which neutron absorption, voids, and/or material boundaries are present. In the context of these limitations, identify a fissile system for which a diffusion theory solution would be adequate.« less

Integral nuclear data validation using experimental spent nuclear fuel compositions

DOE PAGES

Gauld, Ian C.; Williams, Mark L.; Michel-Sendis, Franco; ...

2017-07-19

Measurements of the isotopic contents of spent nuclear fuel provide experimental data that are a prerequisite for validating computer codes and nuclear data for many spent fuel applications. Under the auspices of the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) and guidance of the Expert Group on Assay Data of Spent Nuclear Fuel of the NEA Working Party on Nuclear Criticality Safety, a new database of expanded spent fuel isotopic compositions has been compiled. The database, Spent Fuel Compositions (SFCOMPO) 2.0, includes measured data for more than 750 fuel samples acquired from 44 different reactors andmore » representing eight different reactor technologies. Measurements for more than 90 isotopes are included. This new database provides data essential for establishing the reliability of code systems for inventory predictions, but it also has broader potential application to nuclear data evaluation. Furthermore, the database, together with adjoint based sensitivity and uncertainty tools for transmutation systems developed to quantify the importance of nuclear data on nuclide concentrations, are described.« less

Integral nuclear data validation using experimental spent nuclear fuel compositions

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

Gauld, Ian C.; Williams, Mark L.; Michel-Sendis, Franco

Measurements of the isotopic contents of spent nuclear fuel provide experimental data that are a prerequisite for validating computer codes and nuclear data for many spent fuel applications. Under the auspices of the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) and guidance of the Expert Group on Assay Data of Spent Nuclear Fuel of the NEA Working Party on Nuclear Criticality Safety, a new database of expanded spent fuel isotopic compositions has been compiled. The database, Spent Fuel Compositions (SFCOMPO) 2.0, includes measured data for more than 750 fuel samples acquired from 44 different reactors andmore » representing eight different reactor technologies. Measurements for more than 90 isotopes are included. This new database provides data essential for establishing the reliability of code systems for inventory predictions, but it also has broader potential application to nuclear data evaluation. Furthermore, the database, together with adjoint based sensitivity and uncertainty tools for transmutation systems developed to quantify the importance of nuclear data on nuclide concentrations, are described.« less

Nuclear rocket propulsion technology - A joint NASA/DOE project

NASA Technical Reports Server (NTRS)

Clark, John S.

1991-01-01

NASA and the DOE have initiated critical technology development for nuclear rocket propulsion systems for SEI human and robotic missions to the moon and to Mars. The activities and project plan of the interagency project planning team in FY 1990 and 1991 are summarized. The project plan includes evolutionary technology development for both nuclear thermal and nuclear electric propulsion systems.

Improving Insider Threat Training Awareness and Mitigation Programs at Nuclear Facilities.

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

Abbott, Shannon

In recent years, insider threat programs have become an important aspect of nuclear security, and nuclear security training courses. However, many nuclear security insider threat programs fail to address the insider threat attack and monitoring potential that exists on information technology (IT) systems. This failure is critical because of the importance of information technology and networks in today’s world. IT systems offer an opportunity to perpetrate dangerous insider attacks, but they also present an opportunity to monitor for them and prevent them. This paper suggests a number of best practices for monitoring and preventing insider attacks on IT systems, andmore » proposes the development of a new IT insider threat tabletop that can be used to help train nuclear security practitioners on how best to implement IT insider threat prevention best practices. The development of IT insider threat best practices and a practical tabletop exercise will allow nuclear security practitioners to improve nuclear security trainings as it integrates a critical part of insider threat prevention into the broader nuclear security system.« less

Early warning signals for critical transitions in a thermoacoustic system

PubMed Central

Gopalakrishnan, E. A.; Sharma, Yogita; John, Tony; Dutta, Partha Sharathi; Sujith, R. I.

2016-01-01

Dynamical systems can undergo critical transitions where the system suddenly shifts from one stable state to another at a critical threshold called the tipping point. The decrease in recovery rate to equilibrium (critical slowing down) as the system approaches the tipping point can be used to identify the proximity to a critical transition. Several measures have been adopted to provide early indications of critical transitions that happen in a variety of complex systems. In this study, we use early warning indicators to predict subcritical Hopf bifurcation occurring in a thermoacoustic system by analyzing the observables from experiments and from a theoretical model. We find that the early warning measures perform as robust indicators in the presence and absence of external noise. Thus, we illustrate the applicability of these indicators in an engineering system depicting critical transitions. PMID:27767065

Incineration of nuclear waste by accelerator

NASA Astrophysics Data System (ADS)

Martino, J.; Fioni, G.; Leray, S.

1998-10-01

An important international effort is devoted to find a suitable solution to incinerate radioactive nuclear waste issued from conventional power plants and from nuclear disarmament. Practically all innovative projects consist of a sub critical system driven by an external neutron source obtained by spallation induced by a high intensity proton accelerator irradiating a heavy target. New nuclear data measurements are necessary for the realization of these systems, in particular a good knowledge of the spallation process and of the neutron cross sections for transuranic elements are essential.

Critical Thresholds in Earth-System Dynamics

NASA Astrophysics Data System (ADS)

Rothman, D.

2017-12-01

The history of the Earth system is a story of change. Some changesare gradual and benign, but others, especially those associated withcatastrophic mass extinction, are relatively abrupt and destructive.What sets one group apart from the other? Here I hypothesize thatperturbations of Earth's carbon cycle lead to mass extinction if theyexceed either a critical rate at long time scales or a critical sizeat short time scales. By analyzing 31 carbon-isotopic events duringthe last 542 million years, I identify the critical rate with a limitimposed by mass conservation. Further analysis identifies thecrossover timescale separating fast from slow events with thetimescale of the ocean's homeostatic response to a change in pH. Theproduct of the critical rate and the crossover timescale then yieldsthe critical size. The modern critical size for the marine carboncycle is roughly similar to the mass of carbon that human activitieswill likely have added to the oceans by the year 2100.

78 FR 38739 - Special Nuclear Material Control and Accounting Systems for Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-27

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0109] Special Nuclear Material Control and Accounting... Guide (RG) 5.29, ``Special Nuclear Material Control and Accounting Systems for Nuclear Power Plants... material control and accounting. This guide applies to all nuclear power plants. ADDRESSES: Please refer to...

THE NUCLEAR RAMJET PROPULSION SYSTEM

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

Merkle, T.C.

1959-06-30

The most practical nuclear ramjet systems consist of a suituble inlet diffusor system followed by a singlepass, straight-through heat exchanger (reactor) which couples into a typical exhaust nozzle. Within this framework, possibilities ars governed by the aerodynamic requirements of flight, the nuclear requirements of the reactor, the chemical problems associated with breathing air, and the mechanical properties of materials at elevated temperatures. The major research and development areas which must be entered in the actual production of such an engine are discussed. (W.D.M.)

Probabilistic Scenario-based Seismic Risk Analysis for Critical Infrastructures Method and Application for a Nuclear Power Plant

NASA Astrophysics Data System (ADS)

Klügel, J.

2006-12-01

Deterministic scenario-based seismic hazard analysis has a long tradition in earthquake engineering for developing the design basis of critical infrastructures like dams, transport infrastructures, chemical plants and nuclear power plants. For many applications besides of the design of infrastructures it is of interest to assess the efficiency of the design measures taken. These applications require a method allowing to perform a meaningful quantitative risk analysis. A new method for a probabilistic scenario-based seismic risk analysis has been developed based on a probabilistic extension of proven deterministic methods like the MCE- methodology. The input data required for the method are entirely based on the information which is necessary to perform any meaningful seismic hazard analysis. The method is based on the probabilistic risk analysis approach common for applications in nuclear technology developed originally by Kaplan & Garrick (1981). It is based (1) on a classification of earthquake events into different size classes (by magnitude), (2) the evaluation of the frequency of occurrence of events, assigned to the different classes (frequency of initiating events, (3) the development of bounding critical scenarios assigned to each class based on the solution of an optimization problem and (4) in the evaluation of the conditional probability of exceedance of critical design parameters (vulnerability analysis). The advantage of the method in comparison with traditional PSHA consists in (1) its flexibility, allowing to use different probabilistic models for earthquake occurrence as well as to incorporate advanced physical models into the analysis, (2) in the mathematically consistent treatment of uncertainties, and (3) in the explicit consideration of the lifetime of the critical structure as a criterion to formulate different risk goals. The method was applied for the evaluation of the risk of production interruption losses of a nuclear power plant during its

Testing of Liquid Metal Components for Nuclear Surface Power Systems

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Pearson, J. B.; Godfroy, T. J.; Schoenfeld, M.; Webster, K.; Briggs, M. H.; Geng, S. M.; Adkins, H. E.; Werner, J. E.

2010-01-01

The capability to perform testing at both the module/component level and in near prototypic reactor configurations using a non-nuclear test methodology allowed for evaluation of two components critical to the development of a potential nuclear fission power system for the lunar surface. A pair of 1 kW Stirling power convertors, similar to the type that would be used in a reactor system to convert heat to electricity, were integrated into a reactor simulator system to determine their performance using pumped NaK as the hot side working fluid. The performance in the pumped-NaK system met or exceed the baseline performance measurements where the converters were electrically heated. At the maximum hot-side temperature of 550 C the maximum output power was 2375 watts. A specially-designed test apparatus was fabricated and used to quantify the performance of an annular linear induction pump that is similar to the type that could be used to circulate liquid metal through the core of a space reactor system. The errors on the measurements were generally much smaller than the magnitude of the measurements, permitting accurate performance evaluation over a wide range of operating conditions. The pump produced flow rates spanning roughly 0.16 to 5.7 l/s (2.5 to 90 GPM), and delta p levels from less than 1 kPa to 90 kPa (greater than 0.145 psi to roughly 13 psi). At the nominal FSP system operating temperature of 525 C the maximum efficiency was just over 4%.

Control of finite critical behaviour in a small-scale social system

NASA Astrophysics Data System (ADS)

Daniels, Bryan C.; Krakauer, David C.; Flack, Jessica C.

2017-02-01

Many adaptive systems sit near a tipping or critical point. For systems near a critical point small changes to component behaviour can induce large-scale changes in aggregate structure and function. Criticality can be adaptive when the environment is changing, but entails reduced robustness through sensitivity. This tradeoff can be resolved when criticality can be tuned. We address the control of finite measures of criticality using data on fight sizes from an animal society model system (Macaca nemestrina, n=48). We find that a heterogeneous, socially organized system, like homogeneous, spatial systems (flocks and schools), sits near a critical point; the contributions individuals make to collective phenomena can be quantified; there is heterogeneity in these contributions; and distance from the critical point (DFC) can be controlled through biologically plausible mechanisms exploiting heterogeneity. We propose two alternative hypotheses for why a system decreases the distance from the critical point.

Space tug propulsion system failure mode, effects and criticality analysis

NASA Technical Reports Server (NTRS)

Boyd, J. W.; Hardison, E. P.; Heard, C. B.; Orourke, J. C.; Osborne, F.; Wakefield, L. T.

1972-01-01

For purposes of the study, the propulsion system was considered as consisting of the following: (1) main engine system, (2) auxiliary propulsion system, (3) pneumatic system, (4) hydrogen feed, fill, drain and vent system, (5) oxygen feed, fill, drain and vent system, and (6) helium reentry purge system. Each component was critically examined to identify possible failure modes and the subsequent effect on mission success. Each space tug mission consists of three phases: launch to separation from shuttle, separation to redocking, and redocking to landing. The analysis considered the results of failure of a component during each phase of the mission. After the failure modes of each component were tabulated, those components whose failure would result in possible or certain loss of mission or inability to return the Tug to ground were identified as critical components and a criticality number determined for each. The criticality number of a component denotes the number of mission failures in one million missions due to the loss of that component. A total of 68 components were identified as critical with criticality numbers ranging from 1 to 2990.

A critical incident reporting system in anaesthesia.

PubMed

Madzimbamuto, F D; Chiware, R

2001-01-01

To audit the recently established Critical Incident Reporting System in the Department of Anaesthesia and Critical Care Medicine, University of Zimbabwe Medical School. The system was set up with the purpose of improving the quality of care delivered by the department. Cross sectional study. A critical incident was defined as 'any adverse and reversible event in theatre, during or immediately after surgery that if it persisted without correction would cause harm to the patient'. The anaesthetic or recovery room staff filled a critical incident form anonymously. Data was collected from critical incident reporting forms for analysis. The anaesthetic service in the two teaching hospitals of Harare Central and Parirenyatwa General Hospitals. Between May and October 2000, 62 completed critical incident forms were collected. The nature of the incident and the monitoring used were recorded, the cause was classified as human, equipment or monitoring failure and the outcome for each patient reported. There was no formal system for reminding staff to fill in their critical incident forms. A total of 14,165 operations were performed over the reporting period: 62 critical incident forms were collected, reporting 130 incidents, giving a rate of 0.92% (130/14,165). Of these, 42 patients were emergencies and 20 elective. The incidents were hypotension, hypoxia, bradycardia, ECG changes, aspiration, laryngospasm, high spinal, and cardiac arrest. Monitoring present on patients who had critical incidents was: capnography 57%, oxymetry 90% and ECG 100%. Other monitors are not reported. Human error contributed in 32/62 of patients and equipment failure in 31/62 of patients. Patient outcome showed 15% died, 23% were unplanned admissions to HDU while 62% were discharged to the ward with little or no adverse outcome. Despite some under reporting, the critical incident rate was within the range reported in the literature. Supervision of juniors is not adequate, especially on call. The

Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores

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

Krass, A.W.

2005-12-19

This report describes computational benchmark models for nuclear criticality derived from descriptions of the Systems for Nuclear Auxiliary Power (SNAP) Critical Assembly (SCA)-4B experimental criticality program conducted by Atomics International during the early 1960's. The selected experimental configurations consist of fueled SNAP 10A/2-type reactor cores subject to varied conditions of water immersion and reflection under experimental control to measure neutron multiplication. SNAP 10A/2-type reactor cores are compact volumes fueled and moderated with the hydride of highly enriched uranium-zirconium alloy. Specifications for the materials and geometry needed to describe a given experimental configuration for a model using MCNP5 are provided. Themore » material and geometry specifications are adequate to permit user development of input for alternative nuclear safety codes, such as KENO. A total of 73 distinct experimental configurations are described.« less

Nuclear Hybrid Energy Systems FY16 Modeling Efforts at ORNL

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

Cetiner, Sacit M.; Greenwood, Michael Scott; Harrison, Thomas J.

A nuclear hybrid system uses a nuclear reactor as the basic power generation unit. The power generated by the nuclear reactor is utilized by one or more power customers as either thermal power, electrical power, or both. In general, a nuclear hybrid system will couple the nuclear reactor to at least one thermal power user in addition to the power conversion system. The definition and architecture of a particular nuclear hybrid system is flexible depending on local markets needs and opportunities. For example, locations in need of potable water may be best served by coupling a desalination plant to themore » nuclear system. Similarly, an area near oil refineries may have a need for emission-free hydrogen production. A nuclear hybrid system expands the nuclear power plant from its more familiar central power station role by diversifying its immediately and directly connected customer base. The definition, design, analysis, and optimization work currently performed with respect to the nuclear hybrid systems represents the work of three national laboratories. Idaho National Laboratory (INL) is the lead lab working with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory. Each laboratory is providing modeling and simulation expertise for the integration of the hybrid system.« less

Adaptive Critic-based Neurofuzzy Controller for the Steam Generator Water Level

NASA Astrophysics Data System (ADS)

Fakhrazari, Amin; Boroushaki, Mehrdad

2008-06-01

In this paper, an adaptive critic-based neurofuzzy controller is presented for water level regulation of nuclear steam generators. The problem has been of great concern for many years as the steam generator is a highly nonlinear system showing inverse response dynamics especially at low operating power levels. Fuzzy critic-based learning is a reinforcement learning method based on dynamic programming. The only information available for the critic agent is the system feedback which is interpreted as the last action the controller has performed in the previous state. The signal produced by the critic agent is used alongside the backpropagation of error algorithm to tune online conclusion parts of the fuzzy inference rules. The critic agent here has a proportional-derivative structure and the fuzzy rule base has nine rules. The proposed controller shows satisfactory transient responses, disturbance rejection and robustness to model uncertainty. Its simple design procedure and structure, nominates it as one of the suitable controller designs for the steam generator water level control in nuclear power plant industry.

Nuclear electric propulsion reactor control systems status

NASA Technical Reports Server (NTRS)

Ferg, D. A.

1973-01-01

The thermionic reactor control system design studies conducted over the past several years for a nuclear electric propulsion system are described and summarized. The relevant reactor control system studies are discussed in qualitative terms, pointing out the significant advantages and disadvantages including the impact that the various control systems would have on the nuclear electric propulsion system design. A recommendation for the reference control system is made, and a program for future work leading to an engineering model is described.

Chemical dosimetry system for criticality accidents.

PubMed

Miljanić, Saveta; Ilijas, Boris

2004-01-01

Ruder Bosković Institute (RBI) criticality dosimetry system consists of a chemical dosimetry system for measuring the total (neutron + gamma) dose, and a thermoluminescent (TL) dosimetry system for a separate determination of the gamma ray component. The use of the chemical dosemeter solution chlorobenzene-ethanol-trimethylpentane (CET) is based on the radiolytic formation of hydrochloric acid, which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552 nm is responsible for a high sensitivity of the system: doses in the range 0.2-15 Gy can be measured. The dosemeter has been designed as a glass ampoule filled with the CET solution and inserted into a pen-shaped plastic holder. For dose determinations, a newly constructed optoelectronic reader has been used. The RBI team took part in the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002, with the CET dosimetry system. For gamma ray dose determination TLD-700 TL detectors were used. The results obtained with CET dosemeter show very good agreement with the reference values.

C-terminal motifs in promyelocytic leukemia protein isoforms critically regulate PML nuclear body formation.

PubMed

Li, Chuang; Peng, Qiongfang; Wan, Xiao; Sun, Haili; Tang, Jun

2017-10-15

Promyelocytic leukemia protein (PML) nuclear bodies (NBs), which are sub-nuclear protein structures, are involved in a variety of important cellular functions. PML-NBs are assembled by PML isoforms, and contact between small ubiquitin-like modifiers (SUMOs) with the SUMO interaction motif (SIM) are critically involved in this process. PML isoforms contain a common N-terminal region and a variable C-terminus. However, the contribution of the C-terminal regions to PML-NB formation remains poorly defined. Here, using high-resolution microscopy, we show that mutation of the SIM distinctively influences the structure of NBs formed by each individual PML isoform, with that of PML-III and PML-V minimally changed, and PML-I and PML-IV dramatically impaired. We further identify several C-terminal elements that are important in regulating NB structure and provide strong evidence to suggest that the 8b element in PML-IV possesses a strong ability to interact with SUMO-1 and SUMO-2, and critically participates in NB formation. Our findings highlight the importance of PML C-termini in NB assembly and function, and provide molecular insight into the PML-NB assembly of each distinctive isoform. © 2017. Published by The Company of Biologists Ltd.

Verification of MCNP6.2 for Nuclear Criticality Safety Applications

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

Brown, Forrest B.; Rising, Michael Evan; Alwin, Jennifer Louise

2017-05-10

Several suites of verification/validation benchmark problems were run in early 2017 to verify that the new production release of MCNP6.2 performs correctly for nuclear criticality safety applications (NCS). MCNP6.2 results for several NCS validation suites were compared to the results from MCNP6.1 [1] and MCNP6.1.1 [2]. MCNP6.1 is the production version of MCNP® released in 2013, and MCNP6.1.1 is the update released in 2014. MCNP6.2 includes all of the standard features for NCS calculations that have been available for the past 15 years, along with new features for sensitivity-uncertainty based methods for NCS validation [3]. Results from the benchmark suitesmore » were compared with results from previous verification testing [4-8]. Criticality safety analysts should consider testing MCNP6.2 on their particular problems and validation suites. No further development of MCNP5 is planned. MCNP6.1 is now 4 years old, and MCNP6.1.1 is now 3 years old. In general, released versions of MCNP are supported only for about 5 years, due to resource limitations. All future MCNP improvements, bug fixes, user support, and new capabilities are targeted only to MCNP6.2 and beyond.« less

Evaluation of the concrete shield compositions from the 2010 criticality accident alarm system benchmark experiments at the CEA Valduc SILENE facility

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

Miller, Thomas Martin; Celik, Cihangir; Dunn, Michael E

In October 2010, a series of benchmark experiments were conducted at the French Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA) Valduc SILENE facility. These experiments were a joint effort between the United States Department of Energy Nuclear Criticality Safety Program and the CEA. The purpose of these experiments was to create three benchmarks for the verification and validation of radiation transport codes and evaluated nuclear data used in the analysis of criticality accident alarm systems. This series of experiments consisted of three single-pulsed experiments with the SILENE reactor. For the first experiment, the reactor was bare (unshielded), whereasmore » in the second and third experiments, it was shielded by lead and polyethylene, respectively. The polyethylene shield of the third experiment had a cadmium liner on its internal and external surfaces, which vertically was located near the fuel region of SILENE. During each experiment, several neutron activation foils and thermoluminescent dosimeters (TLDs) were placed around the reactor. Nearly half of the foils and TLDs had additional high-density magnetite concrete, high-density barite concrete, standard concrete, and/or BoroBond shields. CEA Saclay provided all the concrete, and the US Y-12 National Security Complex provided the BoroBond. Measurement data from the experiments were published at the 2011 International Conference on Nuclear Criticality (ICNC 2011) and the 2013 Nuclear Criticality Safety Division (NCSD 2013) topical meeting. Preliminary computational results for the first experiment were presented in the ICNC 2011 paper, which showed poor agreement between the computational results and the measured values of the foils shielded by concrete. Recently the hydrogen content, boron content, and density of these concrete shields were further investigated within the constraints of the previously available data. New computational results for the first experiment are now

Failure Mode, Effects, and Criticality Analysis (FMECA)

DTIC Science & Technology

1993-04-01

Preliminary Failure Modes, Effects and Criticality Analysis (FMECA) of the Brayton Isotope Power System Ground Demonstration System, Report No. TID 27301...No. TID/SNA - 3015, Aeroject Nuclear Systems Co., Sacramento, California: 1970. 95. Taylor , J.R. A Formalization of Failure Mode Analysis of Control...Roskilde, Denmark: 1973. 96. Taylor , J.R. A Semi-Automatic Method for Oualitative Failure Mode Analysis. Report No. RISO-M-1707. Available from a

Real-world aspects of the nuclear criticality safety program at the University of Tennessee-Knoxville

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

Bentley, C.L.; Dunn, M.E.; Goluoglu, S.

1996-12-31

The nuclear criticality safety (NCS) program at the University of Tennessee-Knoxville (UTK) emphasizes the {open_quotes}real world{close_quotes} in the NCS courses that are offered and also the NCS research that is conducted. Two NCS courses are offered at UTK. The first course is an introduction to the NCS field, which uses the text by Knief and includes an overview of criticality accidents that have actually happened, standards that are currently in use and being developed, and state-of-the-art computer methods and codes. The students learn the same codes, including both theory and application, that are used by most professionals in the NCSmore » field. Thus, if a student accepts a job offer in the NCS area after graduation, he or she is capable of doing productive NCS work the first day on the job. Subcritical limits, hand-calculation methods, current regulations [both U.S. Department of Energy (DOE) and U.S. Nuclear Regulatory Commission (NRC)] and current practices are also discussed in the introductory course. The second course emphasizes real world experience and is taught by five instructors with over 100 years of combined experience.« less

WTEC monograph on instrumentation, control and safety systems of Canadian nuclear facilities

NASA Technical Reports Server (NTRS)

Uhrig, Robert E.; Carter, Richard J.

1993-01-01

This report updates a 1989-90 survey of advanced instrumentation and controls (I&C) technologies and associated human factors issues in the U.S. and Canadian nuclear industries carried out by a team from Oak Ridge National Laboratory (Carter and Uhrig 1990). The authors found that the most advanced I&C systems are in the Canadian CANDU plants, where the newest plant (Darlington) has digital systems in almost 100 percent of its control systems and in over 70 percent of its plant protection system. Increased emphasis on human factors and cognitive science in modern control rooms has resulted in a reduced workload for the operators and the elimination of many human errors. Automation implemented through digital instrumentation and control is effectively changing the role of the operator to that of a systems manager. The hypothesis that properly introducing digital systems increases safety is supported by the Canadian experience. The performance of these digital systems has been achieved using appropriate quality assurance programs for both hardware and software development. Recent regulatory authority review of the development of safety-critical software has resulted in the creation of isolated software modules with well defined interfaces and more formal structure in the software generation. The ability of digital systems to detect impending failures and initiate a fail-safe action is a significant safety issue that should be of special interest to nuclear utilities and regulatory authorities around the world.

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

Critical behavior in the system cyclopentanone + water + secondary butyl alcohol

NASA Astrophysics Data System (ADS)

Krishna, U. Santhi; Unni, P. K. Madhavan

2018-05-01

We report detailed measurements of coexistence surface in the ternary system cylcopentanone + water + secondary butyl alcohol. The coexistence surface is seen to have an unusual tunnel like feature and is a potential system in which special critical points such as the Quadruple Critical Point (QCP) could be studied. Analysis of coexistence curves indicates that the system shows 3D-Ising like critical behavior.

Cycle Trades for Nuclear Thermal Rocket Propulsion Systems

NASA Technical Reports Server (NTRS)

White, C.; Guidos, M.; Greene, W.

2003-01-01

Nuclear fission has been used as a reliable source for utility power in the United States for decades. Even in the 1940's, long before the United States had a viable space program, the theoretical benefits of nuclear power as applied to space travel were being explored. These benefits include long-life operation and high performance, particularly in the form of vehicle power density, enabling longer-lasting space missions. The configurations for nuclear rocket systems and chemical rocket systems are similar except that a nuclear rocket utilizes a fission reactor as its heat source. This thermal energy can be utilized directly to heat propellants that are then accelerated through a nozzle to generate thrust or it can be used as part of an electricity generation system. The former approach is Nuclear Thermal Propulsion (NTP) and the latter is Nuclear Electric Propulsion (NEP), which is then used to power thruster technologies such as ion thrusters. This paper will explore a number of indirect-NTP engine cycle configurations using assumed performance constraints and requirements, discuss the advantages and disadvantages of each cycle configuration, and present preliminary performance and size results. This paper is intended to lay the groundwork for future efforts in the development of a practical NTP system or a combined NTP/NEP hybrid system.

Kiwi: An Evaluated Library of Uncertainties in Nuclear Data and Package for Nuclear Sensitivity Studies

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

Pruet, J

2007-06-23

This report describes Kiwi, a program developed at Livermore to enable mature studies of the relation between imperfectly known nuclear physics and uncertainties in simulations of complicated systems. Kiwi includes a library of evaluated nuclear data uncertainties, tools for modifying data according to these uncertainties, and a simple interface for generating processed data used by transport codes. As well, Kiwi provides access to calculations of k eigenvalues for critical assemblies. This allows the user to check implications of data modifications against integral experiments for multiplying systems. Kiwi is written in python. The uncertainty library has the same format and directorymore » structure as the native ENDL used at Livermore. Calculations for critical assemblies rely on deterministic and Monte Carlo codes developed by B division.« less

Critical fault patterns determination in fault-tolerant computer systems

NASA Technical Reports Server (NTRS)

Mccluskey, E. J.; Losq, J.

1978-01-01

The method proposed tries to enumerate all the critical fault-patterns (successive occurrences of failures) without analyzing every single possible fault. The conditions for the system to be operating in a given mode can be expressed in terms of the static states. Thus, one can find all the system states that correspond to a given critical mode of operation. The next step consists in analyzing the fault-detection mechanisms, the diagnosis algorithm and the process of switch control. From them, one can find all the possible system configurations that can result from a failure occurrence. Thus, one can list all the characteristics, with respect to detection, diagnosis, and switch control, that failures must have to constitute critical fault-patterns. Such an enumeration of the critical fault-patterns can be directly used to evaluate the overall system tolerance to failures. Present research is focused on how to efficiently make use of these system-level characteristics to enumerate all the failures that verify these characteristics.

The stability of AID and its function in class-switching are critically sensitive to the identity of its nuclear-export sequence

PubMed Central

Geisberger, Roland; Rada, Cristina; Neuberger, Michael S.

2009-01-01

The carboxyterminal region of activation-induced deaminase (AID) is required for its function in Ig class switch recombination (CSR) and also contains a nuclear-export sequence (NES). Here, based on an extensive fine-structure mutation analysis of the AID NES, as well as from AID chimeras bearing heterologous NESs, we show that while a functional NES is indeed essential for CSR, it is not sufficient. The precise nature of the NES is critical both for AID stabilization and CSR function: minor changes in the NES can perturb stabilization and CSR without jeopardizing nuclear export. The results indicate that the AID NES fulfills a function beyond simply providing a signal for nuclear export and suggest the possibility that the quality of exportin-binding may be critical to the stabilization of AID and its activity in CSR. PMID:19351893

Methods for nuclear air-cleaning-system accident-consequence assessment

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

Andrae, R.W.; Bolstad, J.W.; Gregory, W.S.

1982-01-01

This paper describes a multilaboratory research program that is directed toward addressing many questions that analysts face when performing air cleaning accident consequence assessments. The program involves developing analytical tools and supportive experimental data that will be useful in making more realistic assessments of accident source terms within and up to the atmospheric boundaries of nuclear fuel cycle facilities. The types of accidents considered in this study includes fires, explosions, spills, tornadoes, criticalities, and equipment failures. The main focus of the program is developing an accident analysis handbook (AAH). We will describe the contents of the AAH, which include descriptionsmore » of selected nuclear fuel cycle facilities, process unit operations, source-term development, and accident consequence analyses. Three computer codes designed to predict gas and material propagation through facility air cleaning systems are described. These computer codes address accidents involving fires (FIRAC), explosions (EXPAC), and tornadoes (TORAC). The handbook relies on many illustrative examples to show the analyst how to approach accident consequence assessments. We will use the FIRAC code and a hypothetical fire scenario to illustrate the accident analysis capability.« less

Quantum wavepacket ab initio molecular dynamics: an approach for computing dynamically averaged vibrational spectra including critical nuclear quantum effects.

PubMed

Sumner, Isaiah; Iyengar, Srinivasan S

2007-10-18

We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.

Thermoelectric-Driven Sustainable Sensing and Actuation Systems for Fault-Tolerant Nuclear Incidents

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

Longtin, Jon

2016-02-08

The Fukushima Daiichi nuclear incident in March 2011 represented an unprecedented stress test on the safety and backup systems of a nuclear power plant. The lack of reliable information from key components due to station blackout was a serious setback, leaving sensing, actuation, and reporting systems unable to communicate, and safety was compromised. Although there were several independent backup power sources for required safety function on site, ultimately the batteries were drained and the systems stopped working. If, however, key system components were instrumented with self-powered sensing and actuation packages that could report indefinitely on the status of the system,more » then critical system information could be obtained while providing core actuation and control during off-normal status for as long as needed. This research project focused on the development of such a self-powered sensing and actuation system. The electrical power is derived from intrinsic heat in the reactor components, which is both reliable and plentiful. The key concept was based around using thermoelectric generators that can be integrated directly onto key nuclear components, including pipes, pump housings, heat exchangers, reactor vessels, and shielding structures, as well as secondary-side components. Thermoelectric generators are solid-state devices capable of converting heat directly into electricity. They are commercially available technology. They are compact, have no moving parts, are silent, and have excellent reliability. The key components to the sensor package include a thermoelectric generator (TEG), microcontroller, signal processing, and a wireless radio package, environmental hardening to survive radiation, flooding, vibration, mechanical shock (explosions), corrosion, and excessive temperature. The energy harvested from the intrinsic heat of reactor components can be then made available to power sensors, provide bi-directional communication, recharge batteries

The Analysis of the System of special water purification of Beloyarskaya Nuclear Power Plant unit BN-800

NASA Astrophysics Data System (ADS)

Valtseva, A. I.; Bibik, I. S.

2017-11-01

This article discusses how the latest system of special water purification KPF-30, designed specifically for the fourth power unit of Beloyarskaya nuclear power plant, which has a number of advantages over other water purification systems as chemical-physical and technical-economic, environmental, and other industrial indicators. The scheme covered in this article systems of special water purification involves the use of a hydrocyclone at the preliminary stage of water treatment, as a worthy alternative to ion-exchange filters, which can significantly reduce the volume of toxic waste. The world community implements the project of closing the nuclear fuel cycle, there is a need to improve the reliability of the equipment for safe processes and development of critical and supercritical parameters in the nuclear industry. Essentially, on operated NPP units, the only factor that can cost-effectively optimize to improve the reliability of equipment is the water chemistry. System KPF30 meets the principles and criteria of ecological safety, demonstrating the justification for reagent less method of water treatment on the main stages, in which no formation of toxic wastes, leading to irreversible consequences of environmental pollution and helps to conserve water.

An adaptive load-following control system for a space nuclear power system

NASA Astrophysics Data System (ADS)

Metzger, John D.; El-Genk, Mohamed S.

An adaptive load-following control system is proposed for a space nuclear power system. The conceptual design of the SP-100 space nuclear power system proposes operating the nuclear reactor at a base thermal power and accommodating changes in the electrical power demand with a shunt regulator. It is necessary to increase the reactor thermal power if the payload electrical demand exceeds the peak system electrical output for the associated reactor power. When it is necessary to change the nuclear reactor power to meet a change in the power demand, the power ascension or descension must be accomplished in a predetermined manner to avoid thermal stresses in the system and to achieve the desired reactor period. The load-following control system described has the ability to adapt to changes in the system and to changes in the satellite environment. The application is proposed of the model reference adaptive control (MRAC). The adaptive control system has the ability to control the dynamic response of nonlinear systems. Three basic subsets of adaptive control are: (1) gain scheduling, (2) self-tuning regulators, and (3) model reference adaptive control.

Effects of stressor characteristics on early warning signs of critical transitions and "critical coupling" in complex dynamical systems.

PubMed

Blume, Steffen O P; Sansavini, Giovanni

2017-12-01

Complex dynamical systems face abrupt transitions into unstable and catastrophic regimes. These critical transitions are triggered by gradual modifications in stressors, which push the dynamical system towards unstable regimes. Bifurcation analysis can characterize such critical thresholds, beyond which systems become unstable. Moreover, the stochasticity of the external stressors causes small-scale fluctuations in the system response. In some systems, the decomposition of these signal fluctuations into precursor signals can reveal early warning signs prior to the critical transition. Here, we present a dynamical analysis of a power system subjected to an increasing load level and small-scale stochastic load perturbations. We show that the auto- and cross-correlations of bus voltage magnitudes increase, leading up to a Hopf bifurcation point, and further grow until the system collapses. This evidences a gradual transition into a state of "critical coupling," which is complementary to the established concept of "critical slowing down." Furthermore, we analyze the effects of the type of load perturbation and load characteristics on early warning signs and find that gradient changes in the autocorrelation provide early warning signs of the imminent critical transition under white-noise but not for auto-correlated load perturbations. Furthermore, the cross-correlation between all voltage magnitude pairs generally increases prior to and beyond the Hopf bifurcation point, indicating "critical coupling," but cannot provide early warning indications. Finally, we show that the established early warning indicators are oblivious to limit-induced bifurcations and, in the case of the power system model considered here, only react to an approaching Hopf bifurcation.

Nuclear plants gain integrated information systems

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

Villavicencio-Ramirez, A.; Rodriquez-Alvarez, J.M.

1994-10-01

With the objective of simplifying the complex mesh of computing devices employed within nuclear power plants, modern technology and integration techniques are being used to form centralized (but backed up) databases and distributed processing and display networks. Benefits are immediate as a result of the integration and the use of standards. The use of a unique data acquisition and database subsystem optimizes the high costs of engineering, as this task is done only once for the life span of the system. This also contributes towards a uniform user interface and allows for graceful expansion and maintenance. This article features anmore » integrated information system, Sistema Integral de Informacion de Proceso (SIIP). The development of this system enabled the Laguna Verde Nuclear Power plant to fully use the already existing universe of signals and its related engineering during all plant conditions, namely, start up, normal operation, transient analysis, and emergency operation. Integrated systems offer many advantages over segregated systems, and this experience should benefit similar development efforts in other electric power utilities, not only for nuclear but also for other types of generating plants.« less

Development and evaluation of a monitoring-aid system for a nuclear power plant in control room system manipulation.

PubMed

Lin, Jhih-Tsong; Chen, Yan-Cheng; Wu, Shih-Chieh; Hwang, Sheue-Ling

2017-01-01

In an advanced nuclear power plant (NPP), the operators are responsible for monitoring a massive number of alarm parameters. To assist the operators, a monitoring-aid system (MAS), that applies four quality control chart methods, was proposed and evaluated. Two types of MAS, namely, text and graph marks, were proposed and compared with the original display. To validate the proposed MAS, 17 professional engineers and operators were invited to join an experiment. Two different system states, normal and abnormal, were simulated. The operators were asked to manipulate the system, monitor the critical parameters, search for operational procedures, and deal with other secondary tasks. The primary and secondary task performance and heart rate were measured. After each task was conducted, three subjective rating questionnaires, namely, mental workload, situation awareness, and preference ratings, were implemented for the proposed MAS and the original system. With the assistance of the MAS, the alarm detection rate, secondary task performance, and subjective mental workload demonstrate significant improvements. The proposed MAS helps the operators monitor critical parameters. Therefore, the MAS should be considered for implementation with the control panel to increase the safety of NPPs. Furthermore, the MAS could reduce the mental workload might decrease the health hazard of the operators.

Slow Relaxation in Anderson Critical Systems

NASA Astrophysics Data System (ADS)

Choi, Soonwon; Yao, Norman; Choi, Joonhee; Kucsko, Georg; Lukin, Mikhail

2016-05-01

We study the single particle dynamics in disordered systems with long range hopping, focusing on the critical cases, i.e., the hopping amplitude decays as 1 /rd in d-dimension. We show that with strong on-site potential disorder, the return probability of the particle decays as power-law in time. As on-site potential disorder decreases, the temporal profile smoothly changes from a simple power-law to the sum of multiple power-laws with exponents ranged from 0 to νmax. We analytically compute the decay exponents using a simple resonance counting argument, which quantitatively agrees with exact numerical results. Our result implies that the dynamics in Anderson Critical systems are dominated by resonances. Harvard-MIT CUA, Kwanjeong Educational Fellowship, AFOSR MURI, Samsung Scholarship.

Neural net controlled tag gas sampling system for nuclear reactors

DOEpatents

Gross, Kenneth C.; Laug, Matthew T.; Lambert, John D. B.; Herzog, James P.

1997-01-01

A method and system for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod.

Probalistic Criticality Consequence Evaluation (SCPB:N/A)

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

P. Gottlieb; J.W. Davis; J.R. Massari

1996-09-04

This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department with the objective of providing a comprehensive, conservative estimate of the consequences of the criticality which could possibly occur as the result of commercial spent nuclear fuel emplaced in the underground repository at Yucca Mountain. The consequences of criticality are measured principally in terms of the resulting changes in radionuclide inventory as a function of the power level and duration of the criticality. The purpose of this analysis is to extend the prior estimates of increased radionuclide inventory (Refs. 5.52 and 5.54), for bothmore » internal and external criticality. This analysis, and similar estimates and refinements to be completed before the end of fiscal year 1997, will be provided as input to Total System Performance Assessment-Viability Assessment (TSPA-VA) to demonstrate compliance with the repository performance objectives.« less

Georgia Tech Studies of Sub-Critical Advanced Burner Reactors with a D-T Fusion Tokamak Neutron Source for the Transmutation of Spent Nuclear Fuel

NASA Astrophysics Data System (ADS)

Stacey, W. M.

2009-09-01

The possibility that a tokamak D-T fusion neutron source, based on ITER physics and technology, could be used to drive sub-critical, fast-spectrum nuclear reactors fueled with the transuranics (TRU) in spent nuclear fuel discharged from conventional nuclear reactors has been investigated at Georgia Tech in a series of studies which are summarized in this paper. It is found that sub-critical operation of such fast transmutation reactors is advantageous in allowing longer fuel residence time, hence greater TRU burnup between fuel reprocessing stages, and in allowing higher TRU loading without compromising safety, relative to what could be achieved in a similar critical transmutation reactor. The required plasma and fusion technology operating parameter range of the fusion neutron source is generally within the anticipated operational range of ITER. The implications of these results for fusion development policy, if they hold up under more extensive and detailed analysis, is that a D-T fusion tokamak neutron source for a sub-critical transmutation reactor, built on the basis of the ITER operating experience, could possibly be a logical next step after ITER on the path to fusion electrical power reactors. At the same time, such an application would allow fusion to contribute to meeting the nation's energy needs at an earlier stage by helping to close the fission reactor nuclear fuel cycle.

Software Safety Risk in Legacy Safety-Critical Computer Systems

NASA Technical Reports Server (NTRS)

Hill, Janice; Baggs, Rhoda

2007-01-01

Safety-critical computer systems must be engineered to meet system and software safety requirements. For legacy safety-critical computer systems, software safety requirements may not have been formally specified during development. When process-oriented software safety requirements are levied on a legacy system after the fact, where software development artifacts don't exist or are incomplete, the question becomes 'how can this be done?' The risks associated with only meeting certain software safety requirements in a legacy safety-critical computer system must be addressed should such systems be selected as candidates for reuse. This paper proposes a method for ascertaining formally, a software safety risk assessment, that provides measurements for software safety for legacy systems which may or may not have a suite of software engineering documentation that is now normally required. It relies upon the NASA Software Safety Standard, risk assessment methods based upon the Taxonomy-Based Questionnaire, and the application of reverse engineering CASE tools to produce original design documents for legacy systems.

New reactor technology: safety improvements in nuclear power systems.

PubMed

Corradini, M L

2007-11-01

Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world's electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, nuclear power can only satisfy the need for electricity and other energy-intensive products if it can demonstrate (1) enhanced safety and system reliability, (2) minimal environmental impact via sustainable system designs, and (3) competitive economics. The U.S. Department of Energy with the international community has begun research on the next generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals; in particular, six candidate reactor system designs have been identified. These future nuclear power systems will require advances in materials, reactor physics, as well as thermal-hydraulics to realize their full potential. However, all of these designs must demonstrate enhanced safety above and beyond current light water reactor systems if the next generation of nuclear power plants is to grow in number far beyond the current population. This paper reviews the advanced Generation-IV reactor systems and the key safety phenomena that must be considered to guarantee that enhanced safety can be assured in future nuclear reactor systems.

Critical Time Crystals in Dipolar Systems

NASA Astrophysics Data System (ADS)

Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D.; Abanin, Dmitry A.

2017-07-01

We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017), 10.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

Nuclear rocket propulsion. NASA plans and progress, FY 1991

NASA Technical Reports Server (NTRS)

Clark, John S.; Miller, Thomas J.

1991-01-01

NASA has initiated planning for a technology development project for nuclear rocket propulsion systems for space explorer initiative (SEI) human and robotic missions to the moon and Mars. An interagency project is underway that includes the Department of Energy National Laboratories for nuclear technology development. The activities of the project planning team in FY 1990 and 1991 are summarized. The progress to date is discussed, and the project plan is reviewed. Critical technology issues were identified and include: (1) nuclear fuel temperature, life, and reliability; (2) nuclear system ground test; (3) safety; (4) autonomous system operation and health monitoring; and (5) minimum mass and high specific impulse.

Nuclear rocket propulsion: NASA plans and progress - FY 1991

NASA Technical Reports Server (NTRS)

Clark, John S.; Miller, Thomas J.

1991-01-01

NASA has initiated planning for a technology development project for nuclear rocket propulsion systems for space exploration initiative (SEI) human and robotic missions to the Moon and to Mars. An interagency project is underway that includes the Department of Energy National Laboratories for nuclear technology development. The activities of the project planning team in FY 1990 and 1991 are summarized. The progress to date is discussed, and the project plan is reviewed. Critical technology issues were identified and include: (1) nuclear fuel temperature, life, and reliability; (2) nuclear system ground test; (3) safety; (4) autonomous system operation and health monitoring; and (5) minimum mass and high specific impulse.

Materials challenges for nuclear systems

DOE PAGES

Allen, Todd; Busby, Jeremy; Meyer, Mitch; ...

2010-11-26

The safe and economical operation of any nuclear power system relies to a great extent, on the success of the fuel and the materials of construction. During the lifetime of a nuclear power system which currently can be as long as 60 years, the materials are subject to high temperature, a corrosive environment, and damage from high-energy particles released during fission. The fuel which provides the power for the reactor has a much shorter life but is subject to the same types of harsh environments. This article reviews the environments in which fuels and materials from current and proposed nuclearmore » systems operate and then describes how the creation of the Advanced Test Reactor National Scientific User Facility is allowing researchers from across the U.S. to test their ideas for improved fuels and materials.« less

Neural net controlled tag gas sampling system for nuclear reactors

DOEpatents

Gross, K.C.; Laug, M.T.; Lambert, J.B.; Herzog, J.P.

1997-02-11

A method and system are disclosed for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod. 12 figs.

Manned space flight nuclear system safety. Volume 3: Reactor system preliminary nuclear safety analysis. Part 2: Accident Model Document (AMD)

NASA Technical Reports Server (NTRS)

1972-01-01

The Accident Model Document is one of three documents of the Preliminary Safety Analysis Report (PSAR) - Reactor System as applied to a Space Base Program. Potential terrestrial nuclear hazards involving the zirconium hydride reactor-Brayton power module are identified for all phases of the Space Base program. The accidents/events that give rise to the hazards are defined and abort sequence trees are developed to determine the sequence of events leading to the hazard and the associated probabilities of occurence. Source terms are calculated to determine the magnitude of the hazards. The above data is used in the mission accident analysis to determine the most probable and significant accidents/events in each mission phase. The only significant hazards during the prelaunch and launch ascent phases of the mission are those which arise form criticality accidents. Fission product inventories during this time period were found to be very low due to very limited low power acceptance testing.

Nuclear-renewable hybrid energy systems: Opportunities, interconnections, and needs

DOE PAGES

Ruth, Mark F.; Zinaman, Owen R.; Antkowiak, Mark; ...

2013-12-20

As the U.S. energy system evolves, the amount of electricity from variable-generation sources is likely to increase, which could result in additional times when electricity demand is lower than available production. Therefore, purveyors of technologies that traditionally have provided base-load electricity—such as nuclear power plants—can explore new operating procedures to deal with the associated market signals. Concurrently, innovations in nuclear reactor design coupled with sophisticated control systems now allow for more complex apportionment of heat within an integrated system such as one linked to energy-intensive chemical processes. Our paper explores one opportunity – nuclear-renewable hybrid energy systems. These are definedmore » as integrated facilities comprised of nuclear reactors, renewable energy generation, and industrial processes that can simultaneously address the need for grid flexibility, greenhouse gas emission reductions, and optimal use of investment capital. Six aspects of interaction (interconnections) between elements of nuclear-renewable hybrid energy systems are identified: Thermal, electrical, chemical, hydrogen, mechanical, and information. In addition, system-level aspects affect selection, design, and operation of this hybrid system type. Throughout the paper, gaps and research needs are identified to promote further exploration of the topic.« less

Performance Criteria of Nuclear Space Propulsion Systems

NASA Astrophysics Data System (ADS)

Shepherd, L. R.

Future exploration of the solar system on a major scale will require propulsion systems capable of performance far greater than is achievable with the present generation of rocket engines using chemical propellants. Viable missions going deeper into interstellar space will be even more demanding. Propulsion systems based on nuclear energy sources, fission or (eventually) fusion offer the best prospect for meeting the requirements. The most obvious gain coming from the application of nuclear reactions is the possibility, at least in principle, of obtaining specific impulses a thousandfold greater than can be achieved in chemically energised rockets. However, practical considerations preclude the possibility of exploiting the full potential of nuclear energy sources in any engines conceivable in terms of presently known technology. Achievable propulsive power is a particularly limiting factor, since this determines the acceleration that may be obtained. Conventional chemical rocket engines have specific propulsive powers (power per unit engine mass) in the order of gigawatts per tonne. One cannot envisage the possibility of approaching such a level of performance by orders of magnitude in presently conceivable nuclear propulsive systems. The time taken, under power, to reach a given terminal velocity is proportional to the square of the engine's exhaust velocity and the inverse of its specific power. An assessment of various nuclear propulsion concepts suggests that, even with the most optimistic assumptions, it could take many hundreds of years to attain the velocities necessary to reach the nearest stars. Exploration within a range of the order of a thousand AU, however, would appear to offer viable prospects, even with the low levels of specific power of presently conceivable nuclear engines.

Critical Education for Systemic Change: A World-Systems Analysis Perspective

ERIC Educational Resources Information Center

Griffiths, Tom G.

2015-01-01

This paper both draws on, and seeks to apply, world-systems analysis to a broad, critical education project that builds mass schooling's potential contribution to the process of world-systemic change. In short, this is done by first setting out the world-systems analysis account of the current state, and period of transition, of the capitalist…

Effects of materials and design on the criticality and shielding assessment of canister concepts for the disposal of spent nuclear fuel.

PubMed

Gutiérrez, Miguel Morales; Caruso, Stefano; Diomidis, Nikitas

2018-05-19

According to the Swiss disposal concept, the safety of a deep geological repository for spent nuclear fuel (SNF) is based on a multi-barrier system. The disposal canister is an important component of the engineered barrier system, aiming to provide containment of the SNF for thousands of years. This study evaluates the criticality safety and shielding of candidate disposal canister concepts, focusing on the fulfilment of the sub-criticality criterion and on limiting radiolysis processes at the outer surface of the canister which can enhance corrosion mechanisms. The effective neutron multiplication factor (k-eff) and the surface dose rates are calculated for three different canister designs and material combinations for boiling water reactor (BWR) canisters, containing 12 spent fuel assemblies (SFA), and pressurized water reactor (PWR) canisters, with 4 SFAs. For each configuration, individual criticality and shielding calculations were carried out. The results show that k-eff falls below the defined upper safety limit (USL) of 0.95 for all BWR configurations, while staying above USL for the PWR ones. Therefore, the application of a burnup credit methodology for the PWR case is required, being currently under development. Relevant is also the influence of canister material and internal geometry on criticality, enabling the identification of safer fuel arrangements. For a final burnup of 55MWd/kgHM and 30y cooling time, the combined photon-neutron surface dose rate is well below the threshold of 1 Gy/h defined to limit radiation-induced corrosion of the canister in all cases. Copyright © 2018 Elsevier Ltd. All rights reserved.

NASA-LaRc Flight-Critical Digital Systems Technology Workshop

NASA Technical Reports Server (NTRS)

Meissner, C. W., Jr. (Editor); Dunham, J. R. (Editor); Crim, G. (Editor)

1989-01-01

The outcome is documented of a Flight-Critical Digital Systems Technology Workshop held at NASA-Langley December 13 to 15 1988. The purpose of the workshop was to elicit the aerospace industry's view of the issues which must be addressed for the practical realization of flight-critical digital systems. The workshop was divided into three parts: an overview session; three half-day meetings of seven working groups addressing aeronautical and space requirements, system design for validation, failure modes, system modeling, reliable software, and flight test; and a half-day summary of the research issues presented by the working group chairmen. Issues that generated the most consensus across the workshop were: (1) the lack of effective design and validation methods with support tools to enable engineering of highly-integrated, flight-critical digital systems, and (2) the lack of high quality laboratory and field data on system failures especially due to electromagnetic environment (EME).

Dual mode nuclear rocket system applications.

NASA Technical Reports Server (NTRS)

Boretz, J. E.; Bell, J. M.; Plebuch, R. K.; Priest, C. C.

1972-01-01

Mission areas where the dual-mode nuclear rocket system is superior to nondual-mode systems are demonstrated. It is shown that the dual-mode system is competitive with the nondual-mode system even for those specific missions and particular payload configurations where it does not have a clear-cut advantage.

Nuclear War. The moral dimension

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

Child, J.W.

1985-01-01

U.S. nuclear policy has become the target of increasing criticism during the past decade. Critics often argue that the use of nuclear weapons would be irrational, would destroy humankind, and thus could not serve any rational policy goal. Other critics point to the immortality of the use of nuclear weapons. Both groups condemn U.S. military policy. In Nuclear War, James Child considers and rejects both these lines of criticism. He argues that a policy of deterrence can be both rational and moral; that U.S. nuclear policy is, on balance, based on rational and moral foundations. Child examines near-term consequences ofmore » a nuclear war and finds them ghastly but not unthinkable or incomparable to the havoc produced by previous wars. He also analyzes long-term consequences, such as those proposed by the ''nuclear winter'' theory, and finds the fear of total annihilation of humankind to be unfounded.« less

Technical Application of Nuclear Fission

NASA Astrophysics Data System (ADS)

Denschlag, J. O.

The chapter is devoted to the practical application of the fission process, mainly in nuclear reactors. After a historical discussion covering the natural reactors at Oklo and the first attempts to build artificial reactors, the fundamental principles of chain reactions are discussed. In this context chain reactions with fast and thermal neutrons are covered as well as the process of neutron moderation. Criticality concepts (fission factor η, criticality factor k) are discussed as well as reactor kinetics and the role of delayed neutrons. Examples of specific nuclear reactor types are presented briefly: research reactors (TRIGA and ILL High Flux Reactor), and some reactor types used to drive nuclear power stations (pressurized water reactor [PWR], boiling water reactor [BWR], Reaktor Bolshoi Moshchnosti Kanalny [RBMK], fast breeder reactor [FBR]). The new concept of the accelerator-driven systems (ADS) is presented. The principle of fission weapons is outlined. Finally, the nuclear fuel cycle is briefly covered from mining, chemical isolation of the fuel and preparation of the fuel elements to reprocessing the spent fuel and conditioning for deposit in a final repository.

Accelerator–Reactor Coupling for Energy Production in Advanced Nuclear Fuel Cycles

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

Heidet, Florent; Brown, Nicholas R.; Haj Tahar, Malek

2015-01-01

This article is a review of several accelerator-reactor interface issues and nuclear fuel cycle applications of accelerator-driven subcritical systems. The systems considered here have the primary goal of energy production, but that goal is accomplished via a specific application in various proposed nuclear fuel cycles, such as breed-and-burn of fertile material or burning of transuranic material. Several basic principles are reviewed, starting from the proton beam window including the target, blanket, reactor core, and up to the fuel cycle. We focused on issues of interest, e.g. the impact of the energy required to run the accelerator and associated systems onmore » the potential electricity delivered to the grid. Accelerator-driven systems feature many of the constraints and issues associated with critical reactors, with the added challenges of subcritical operation and coupling to an accelerator. Reliable accelerator operation and avoidance of beam trips are a critically important. One interesting challenge is measurement of blanket subcriticality level during operation. We also reviewed the potential benefits of accelerator-driven systems in various nuclear fuel cycle applications. Ultimately, accelerator-driven subcritical systems with the goal of transmutation of transuranic material have lower 100,000-year radioactivity versus a critical fast reactor with recycle of uranium and plutonium.« less

Accelerator-Reactor Coupling for Energy Production in Advanced Nuclear Fuel Cycles

NASA Astrophysics Data System (ADS)

Heidet, Florent; Brown, Nicholas R.; Haj Tahar, Malek

This article is a review of several accelerator-reactor interface issues and nuclear fuel cycle applications of accelerator-driven subcritical systems. The systems considered here have the primary goal of energy production, but that goal is accomplished via a specific application in various proposed nuclear fuel cycles, such as breed-and-burn of fertile material or burning of transuranic material. Several basic principles are reviewed, starting from the proton beam window including the target, blanket, reactor core, and up to the fuel cycle. We focus on issues of interest, such as the impact of the energy required to run the accelerator and associated systems on the potential electricity delivered to the grid. Accelerator-driven systems feature many of the constraints and issues associated with critical reactors, with the added challenges of subcritical operation and coupling to an accelerator. Reliable accelerator operation and avoidance of beam trips are critically important. One interesting challenge is measurement of blanket subcriticality level during operation. We also review the potential benefits of accelerator-driven systems in various nuclear fuel cycle applications. Ultimately, accelerator-driven subcritical systems with the goal of transmutation of transuranic material have lower 100,000-year radioactivity than a critical fast reactor with recycling of uranium and plutonium.

A realistic chemical system presenting a self-organized critical behavior

NASA Astrophysics Data System (ADS)

Gaveau, Bernard; Latrémolière, Daniel; Moreau, Michel

2003-04-01

We consider a realistic example of chemical system which presents self-organized criticality. We can study the kinetic equations analytically, and show that the conditions for self-organized criticality are satisfied. We find power relaxation laws for certain variables near the critical state, confirming the self-organized critical behavior.

Nuclear core positioning system

DOEpatents

Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

1979-01-01

A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

Experimental results from the VENUS-F critical reference state for the GUINEVERE accelerator driven system project

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

Uyttenhove, W.; Baeten, P.; Ban, G.

The GUINEVERE (Generation of Uninterrupted Intense Neutron pulses at the lead Venus Reactor) project was launched in 2006 within the framework of FP6 EUROTRANS in order to validate on-line reactivity monitoring and subcriticality level determination in Accelerator Driven Systems. Therefore the VENUS reactor at SCK.CEN in Mol (Belgium) was modified towards a fast core (VENUS-F) and coupled to the GENEPI-3C accelerator built by CNRS The accelerator can operate in both continuous and pulsed mode. The VENUS-F core is loaded with enriched Uranium and reflected with solid lead. A well-chosen critical reference state is indispensable for the validation of the on-linemore » subcriticality monitoring methodology. Moreover a benchmarking tool is required for nuclear data research and code validation. In this paper the design and the importance of the critical reference state for the GUINEVERE project are motivated. The results of the first experimental phase on the critical core are presented. The control rods worth is determined by the rod drop technique and the application of the Modified Source Multiplication (MSM) method allows the determination of the worth of the safety rods. The results are implemented in the VENUS-F core certificate for full exploitation of the critical core. (authors)« less

Experimental results from the VENUS-F critical reference state for the GUINEVERE accelerator driven system project

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

Uyttenhove, W.; Baeten, P.; Kochetkov, A.

The GUINEVERE (Generation of Uninterrupted Intense Neutron pulses at the lead Venus Reactor) project was launched in 2006 within the framework of FP6 EUROTRANS in order to validate online reactivity monitoring and subcriticality level determination in accelerator driven systems (ADS). Therefore, the VENUS reactor at SCK.CEN in Mol, Belgium, was modified towards a fast core (VENUS-F) and coupled to the GENEPI-3C accelerator built by CNRS. The accelerator can operate in both continuous and pulsed mode. The VENUS-F core is loaded with enriched Uranium and reflected with solid lead. A well-chosen critical reference state is indispensable for the validation of themore » online subcriticality monitoring methodology. Moreover, a benchmarking tool is required for nuclear data research and code validation. In this paper, the design and the importance of the critical reference state for the GUINEVERE project are motivated. The results of the first experimental phase on the critical core are presented. The control rods worth is determined by the positive period method and the application of the Modified Source Multiplication (MSM) method allows the determination of the worth of the safety rods. The results are implemented in the VENUS-F core certificate for full exploitation of the critical core. (authors)« less

New Nuclear Emergency Prognosis system in Korea

NASA Astrophysics Data System (ADS)

Lee, Hyun-Ha; Jeong, Seung-Young; Park, Sang-Hyun; Lee, Kwan-Hee

2016-04-01

This paper reviews the status of assessment and prognosis system for nuclear emergency response in Korea, especially atmospheric dispersion model. The Korea Institute of Nuclear Safety (KINS) performs the regulation and radiological emergency preparedness of the nuclear facilities and radiation utilizations. Also, KINS has set up the "Radiological Emergency Technical Advisory Plan" and the associated procedures such as an emergency response manual in consideration of the IAEA Safety Standards GS-R-2, GS-G-2.0, and GS-G-2.1. The Radiological Emergency Technical Advisory Center (RETAC) organized in an emergency situation provides the technical advice on radiological emergency response. The "Atomic Computerized Technical Advisory System for nuclear emergency" (AtomCARE) has been developed to implement assessment and prognosis by RETAC. KINS developed Accident Dose Assessment and Monitoring (ADAMO) system in 2015 to reflect the lessons learned from Fukushima accident. It incorporates (1) the dose assessment on the entire Korean peninsula, Asia region, and global region, (2) multi-units accident assessment (3) applying new methodology of dose rate assessment and the source term estimation with inverse modeling, (4) dose assessment and monitoring with the environmental measurements result. The ADAMO is the renovated version of current FADAS of AtomCARE. The ADAMO increases the accuracy of the radioactive material dispersion with applying the LDAPS(Local Data Assimilation Prediction System, Spatial resolution: 1.5 km) and RDAPS(Regional Data Assimilation Prediction System, Spatial resolution: 12km) of weather prediction data, and performing the data assimilation of automatic weather system (AWS) data from Korea Meteorological Administration (KMA) and data from the weather observation tower at NPP site. The prediction model of the radiological material dispersion is based on the set of the Lagrangian Particle model and Lagrangian Puff model. The dose estimation methodology

Nuclear Engine System Simulation (NESS) version 2.0

NASA Technical Reports Server (NTRS)

Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.

1993-01-01

The topics are presented in viewgraph form and include the following; nuclear thermal propulsion (NTP) engine system analysis program development; nuclear thermal propulsion engine analysis capability requirements; team resources used to support NESS development; expanded liquid engine simulations (ELES) computer model; ELES verification examples; NESS program development evolution; past NTP ELES analysis code modifications and verifications; general NTP engine system features modeled by NESS; representative NTP expander, gas generator, and bleed engine system cycles modeled by NESS; NESS program overview; NESS program flow logic; enabler (NERVA type) nuclear thermal rocket engine; prismatic fuel elements and supports; reactor fuel and support element parameters; reactor parameters as a function of thrust level; internal shield sizing; and reactor thermal model.

Critical event management with geographic information system technology

NASA Astrophysics Data System (ADS)

Booth, John F.; Young, Jeffrey M.

1997-02-01

Critical event management at the Los Angeles County Regional Criminal Information Clearinghouse (LACRCIC) provides for the deconfliction of operations, such as reverse stings, arrests, undercover buys/busts, searches, surveillances, and site surveys in the Los Angeles, Orange, Riverside, and San Bernardino county area. During these operations, the opportunity for officer-to-officer confrontation is high, possibly causing a worse case scenario -- officers drawing on each other resulting in friendly fire injuries or casualties. In order to prevent local, state, and federal agencies in the Los Angeles area from experiencing this scenario, the LACRCIC provides around the clock critical event management services via its secure war room. The war room maintains a multicounty detailed street-level map base and geographic information system (GIS) application to support this effort. Operations are telephoned in by the participating agencies and posted in the critical event management system by war room analysts. The application performs both a proximity search around the address and a commonality of suspects search. If a conflict is found, the system alerts the analyst by sounding an audible alarm and flashing the conflicting events on the automated basemap. The analyst then notifies the respective agencies of the conflicting critical events so coordination or rescheduling can occur.

48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

Preliminary design studies on a nuclear seawater desalination system

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

Wibisono, A. F.; Jung, Y. H.; Choi, J.

2012-07-01

Seawater desalination is one of the most promising technologies to provide fresh water especially in the arid region. The most used technology in seawater desalination are thermal desalination (MSF and MED) and membrane desalination (RO). Some developments have been done in the area of coupling the desalination plant with a nuclear reactor to reduce the cost of energy required in thermal desalination. The coupling a nuclear reactor to a desalination plant can be done either by using the co-generation or by using dedicated heat from a nuclear system. The comparison of the co-generation nuclear reactor with desalination plant, dedicated nuclearmore » heat system, and fossil fueled system will be discussed in this paper using economical assessment with IAEA DEEP software. A newly designed nuclear system dedicated for the seawater desalination will also be suggested by KAIST (Korea Advanced Inst. of Science and Technology) research team and described in detail within this paper. The suggested reactor system is using gas cooled type reactor and in this preliminary study the scope of design will be limited to comparison of two cases in different operating temperature ranges. (authors)« less

The Critical Mass Laboratory at Rocky Flats

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

Rothe, Robert E

2003-10-15

The Critical Mass Laboratory (CML) at Rocky Flats northwest of Denver, Colorado, was built in 1964 and commissioned to conduct nuclear experiments on January 28, 1965. It was built to attain more accurate and precise experimental data to ensure nuclear criticality safety at the plant than were previously possible. Prior to its construction, safety data were obtained from long extrapolations of subcritical data (called in situ experiments), calculated parameters from reactor engineering 'models', and a few other imprecise methods. About 1700 critical and critical-approach experiments involving several chemical forms of enriched uranium and plutonium were performed between then and 1988.more » These experiments included single units and arrays of fissile materials, reflected and 'bare' systems, and configurations with various degrees of moderation, as well as some containing strong neutron absorbers. In 1989, a raid by the Federal Bureau of Investigation (FBI) caused the plant as a whole to focus on 'resumption' instead of further criticality safety experiments. Though either not recognized or not admitted for a few years, that FBI raid did sound the death knell for the CML. The plant's optimistic goal of resumption evolved to one of deactivation, decommissioning, and plantwide demolition during the 1990s. The once-proud CML facility was finally demolished in April of 2002.« less

Characterizing noise in the global nuclear weapon monitoring system

NASA Astrophysics Data System (ADS)

Schultz, Colin

2013-03-01

Under the auspices of the Comprehensive Nuclear-Test-Ban Treaty Organization, a worldwide monitoring system designed to detect the illegal testing of nuclear weaponry has been under construction since 1999. The International Monitoring System is composed of a range of sensors, including detectors for hydroacoustic and seismic signals, and when completed, will include 60 infrasound measurement arrays set to detect low-frequency sound waves produced by an atmospheric nuclear detonation.

Earth physicist describes US nuclear test monitoring system

NASA Astrophysics Data System (ADS)

1986-01-01

The U. S. capabilities to monitor underground nuclear weapons tests in the USSR was examined. American methods used in monitoring the underground nuclear tests are enumerated. The U. S. technical means of monitoring Solviet nuclear weapons testing, and whether it is possible to conduct tests that could not be detected by these means are examined. The worldwide seismic station network in 55 countries available to the U. S. for seismic detection and measurement of underground nuclear explosions, and also the systems of seismic research observatories in 15 countries and seismic grouping stations in 12 countries are outlined including the advanced computerized data processing capabilities of these facilities. The level of capability of the U. S. seismic system for monitoring nuclear tests, other, nonseismic means of monitoring, such as hydroacoustic and recording of effects in the atmosphere, ionosphere, and the Earth's magnetic field, are discussed.

FAULT PROPAGATION AND EFFECTS ANALYSIS FOR DESIGNING AN ONLINE MONITORING SYSTEM FOR THE SECONDARY LOOP OF A NUCLEAR POWER PLANT PART OF A HYBRID ENERGY SYSTEM

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

Li, Huijuan; Diao, Xiaoxu; Li, Boyuan

This paper studies the propagation and effects of faults of critical components that pertain to the secondary loop of a nuclear power plant found in Nuclear Hybrid Energy Systems (NHES). This information is used to design an on-line monitoring (OLM) system which is capable of detecting and forecasting faults that are likely to occur during NHES operation. In this research, the causes, features, and effects of possible faults are investigated by simulating the propagation of faults in the secondary loop. The simulation is accomplished by using the Integrated System Failure Analysis (ISFA). ISFA is used for analyzing hardware and softwaremore » faults during the conceptual design phase. In this paper, the models of system components required by ISFA are initially constructed. Then, the fault propagation analysis is implemented, which is conducted under the bounds set by acceptance criteria derived from the design of an OLM system. The result of the fault simulation is utilized to build a database for fault detection and diagnosis, provide preventive measures, and propose an optimization plan for the OLM system.« less

Seismic risk management solution for nuclear power plants

DOE PAGES

Coleman, Justin; Sabharwall, Piyush

2014-12-01

Nuclear power plants should safely operate during normal operations and maintain core-cooling capabilities during off-normal events, including external hazards (such as flooding and earthquakes). Management of external hazards to expectable levels of risk is critical to maintaining nuclear facility and nuclear power plant safety. Seismic risk is determined by convolving the seismic hazard with seismic fragilities (capacity of systems, structures, and components). Seismic isolation (SI) is one protective measure showing promise to minimize seismic risk. Current SI designs (used in commercial industry) reduce horizontal earthquake loads and protect critical infrastructure from the potentially destructive effects of large earthquakes. The benefitmore » of SI application in the nuclear industry is being recognized and SI systems have been proposed in American Society of Civil Engineer Standard 4, ASCE-4, to be released in the winter of 2014, for light water reactors facilities using commercially available technology. The intent of ASCE-4 is to provide criteria for seismic analysis of safety related nuclear structures such that the responses to design basis seismic events, computed in accordance with this standard, will have a small likelihood of being exceeded. The U.S. nuclear industry has not implemented SI to date; a seismic isolation gap analysis meeting was convened on August 19, 2014, to determine progress on implementing SI in the U.S. nuclear industry. The meeting focused on the systems and components that could benefit from SI. As a result, this article highlights the gaps identified at this meeting.« less

Space Nuclear Power Systems

NASA Technical Reports Server (NTRS)

Houts, Michael G.

2012-01-01

Fission power and propulsion systems can enable exciting space exploration missions. These include bases on the moon and Mars; and the exploration, development, and utilization of the solar system. In the near-term, fission surface power systems could provide abundant, constant, cost-effective power anywhere on the surface of the Moon or Mars, independent of available sunlight. Affordable access to Mars, the asteroid belt, or other destinations could be provided by nuclear thermal rockets. In the further term, high performance fission power supplies could enable both extremely high power levels on planetary surfaces and fission electric propulsion vehicles for rapid, efficient cargo and crew transfer. Advanced fission propulsion systems could eventually allow routine access to the entire solar system. Fission systems could also enable the utilization of resources within the solar system.

Accelerator Reactor Coupling for Energy Production in Advanced Nuclear Fuel Cycles

DOE PAGES

Brown, Nicholas R.; Heidet, Florent; Haj Tahar, Malek

2016-01-01

This article is a review of several accelerator–reactor interface issues and nuclear fuel cycle applications of acceleratordriven subcritical systems. The systems considered here have the primary goal of energy production, but that goal is accomplished via a specific application in various proposed nuclear fuel cycles, such as breed-and-burn of fertile material or burning of transuranic material. Several basic principles are reviewed, starting from the proton beam window including the target, blanket, reactor core, and up to the fuel cycle. We focus on issues of interest, such as the impact of the energy required to run the accelerator and associated systemsmore » on the potential electricity delivered to the grid. Accelerator-driven systems feature many of the constraints and issues associated with critical reactors, with the added challenges of subcritical operation and coupling to an accelerator. Reliable accelerator operation and avoidance of beam trips are critically important. One interesting challenge is measurement of blanket subcriticality level during operation. We also review the potential benefits of accelerator-driven systems in various nuclear fuel cycle applications. Ultimately, accelerator-driven subcritical systems with the goal of transmutation of transuranic material have lower 100,000-year radioactivity than a critical fast reactor with recycling of uranium and plutonium.« less

Minimizing human error in radiopharmaceutical preparation and administration via a bar code-enhanced nuclear pharmacy management system.

PubMed

Hakala, John L; Hung, Joseph C; Mosman, Elton A

2012-09-01

The objective of this project was to ensure correct radiopharmaceutical administration through the use of a bar code system that links patient and drug profiles with on-site information management systems. This new combined system would minimize the amount of manual human manipulation, which has proven to be a primary source of error. The most common reason for dosing errors is improper patient identification when a dose is obtained from the nuclear pharmacy or when a dose is administered. A standardized electronic transfer of information from radiopharmaceutical preparation to injection will further reduce the risk of misadministration. Value stream maps showing the flow of the patient dose information, as well as potential points of human error, were developed. Next, a future-state map was created that included proposed corrections for the most common critical sites of error. Transitioning the current process to the future state will require solutions that address these sites. To optimize the future-state process, a bar code system that links the on-site radiology management system with the nuclear pharmacy management system was proposed. A bar-coded wristband connects the patient directly to the electronic information systems. The bar code-enhanced process linking the patient dose with the electronic information reduces the number of crucial points for human error and provides a framework to ensure that the prepared dose reaches the correct patient. Although the proposed flowchart is designed for a site with an in-house central nuclear pharmacy, much of the framework could be applied by nuclear medicine facilities using unit doses. An electronic connection between information management systems to allow the tracking of a radiopharmaceutical from preparation to administration can be a useful tool in preventing the mistakes that are an unfortunate reality for any facility.

Improving US theater nuclear doctrine. a critical analysis

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

Sollinger, J.M.

This monograph argues that the doctrine, equipment, and training of US forces do not meet the demands of fighting a theater nuclear war. Current doctrine rests upon questionable assumptions, lacks the flexibility required to fight a tactical nuclear battle, and limits itself by concentrating on defense. Recommended improvements include increased flexibility and decentralized execution, emphasizing maneuver and dispersion. Service doctrinal writings should focus on enemy forces rather than terrain. Because the nuclear battlefield promises chaos and confusion, US forces need redundant command and control. The equipment of US forces also needs improving, The services must field equipment capable of withstandingmore » the effects of nuclear weapons. In most cases this requirement means making existing procedures work and the hardening of equipment. Some new items of equipment, such as monitoring devices, are needed. Training requires improvement at both the individual and unit levels. Individual enlisted training tends to concentrate specialized knowledge at too high a level. With substantial casualties expected in a nuclear battle, US forces cannot afford to confine specialized knowledge to a few individuals.« less

Nuclear quantum shape-phase transitions in odd-mass systems

NASA Astrophysics Data System (ADS)

Quan, S.; Li, Z. P.; Vretenar, D.; Meng, J.

2018-03-01

Microscopic signatures of nuclear ground-state shape-phase transitions in odd-mass Eu isotopes are explored starting from excitation spectra and collective wave functions obtained by diagonalization of a core-quasiparticle coupling Hamiltonian based on energy density functionals. As functions of the physical control parameter—the number of nucleons—theoretical low-energy spectra, two-neutron separation energies, charge isotope shifts, spectroscopic quadrupole moments, and E 2 reduced transition matrix elements accurately reproduce available data and exhibit more-pronounced discontinuities at neutron number N =90 compared with the adjacent even-even Sm and Gd isotopes. The enhancement of the first-order quantum phase transition in odd-mass systems can be attributed to a shape polarization effect of the unpaired proton which, at the critical neutron number, starts predominantly coupling to Gd core nuclei that are characterized by larger quadrupole deformation and weaker proton pairing correlations compared with the corresponding Sm isotopes.

Nuclear criticality safety calculational analysis for small-diameter containers

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

LeTellier, M.S.; Smallwood, D.J.; Henkel, J.A.

This report documents calculations performed to establish a technical basis for the nuclear criticality safety of favorable geometry containers, sometimes referred to as 5-inch containers, in use at the Portsmouth Gaseous Diffusion Plant. A list of containers currently used in the plant is shown in Table 1.0-1. These containers are currently used throughout the plant with no mass limits. The use of containers with geometries or material types other than those addressed in this evaluation must be bounded by this analysis or have an additional analysis performed. The following five basic container geometries were modeled and bound all container geometriesmore » in Table 1.0-1: (1) 4.32-inch-diameter by 50-inch-high polyethylene bottle; (2) 5.0-inch-diameter by 24-inch-high polyethylene bottle; (3) 5.25-inch-diameter by 24-inch-high steel can ({open_quotes}F-can{close_quotes}); (4) 5.25-inch-diameter by 15-inch-high steel can ({open_quotes}Z-can{close_quotes}); and (5) 5.0-inch-diameter by 9-inch-high polybottle ({open_quotes}CO-4{close_quotes}). Each container type is evaluated using five basic reflection and interaction models that include single containers and multiple containers in normal and in credible abnormal conditions. The uranium materials evaluated are UO{sub 2}F{sub 2}+H{sub 2}O and UF{sub 4}+oil materials at 100% and 10% enrichments and U{sub 3}O{sub 8}, and H{sub 2}O at 100% enrichment. The design basis safe criticality limit for the Portsmouth facility is k{sub eff} + 2{sigma} < 0.95. The KENO study results may be used as the basis for evaluating general use of these containers in the plant.« less

Intact and Degraded Criticality Calculations for the Codisposal of Shippingport LWBR Spent Nuclear Fuel in a Waste Package

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

L.M. Montierth

2000-09-15

The objective of this calculation is to characterize the nuclear criticality safety concerns associated with the codisposal of the U.S. Department of Energy's (DOE) Shippingport Light Water Breeder Reactor (SP LWBR) Spent Nuclear Fuel (SNF) in a 5-Defense High-Level Waste (5-DHLW) Waste Package (WP), which is to be placed in a Monitored Geologic Repository (MGR). The scope of this calculation is limited to the determination of the effective neutron multiplication factor (K{sub eff}) for intact- and degraded-mode internal configurations of the codisposal WP containing Shippingport LWBR seed-type assemblies. The results of this calculation will be used to evaluate criticality issuesmore » and support the analysis that is planed to be performed to demonstrate the viability of the codisposal concept for the MGR. This calculation is associated with the waste package design and was performed in accordance with the DOE SNF Analysis Plan for FY 2000 (See Ref. 22). The document has been prepared in accordance with the Administrative Procedure AP-3.12Q, Calculations (Ref. 23).« less

The Fukushima Nuclear Event and its Implications for Nuclear Power

NASA Astrophysics Data System (ADS)

Golay, Michael

2011-11-01

The combined strong earthquake and super tsunami of 12 March 2011 at the Fukushima nuclear power plant imposed the most severe challenges ever experienced at such a facility. Information regarding the plant response and status remains uncertain, but it is clear that severe damage has been sustained, that the plant staff have responded creatively and that the offsite implications are unlikely to be seriously threatening to the health, if not the prosperity, of the surrounding population. Reexamination of the regulatory constraints of nuclear power will occur worldwide, and some changes are likely; particularly concerning reliance upon active systems for achieving critical safety functions and concerning treatments of used reactor fuel. Whether worldwide expansion of the nuclear power economy will be slowed in the long run is perhaps unlikely and worth discussion.

The nuclear disaster management system in Taiwan: a case study of the third (Maanshan) nuclear power plant.

PubMed

Yang, Yung-Nane

2016-07-01

This paper explores the effectiveness of the nuclear disaster management system in Taiwan via a review of the third (Maanshan) nuclear power plant. In doing so, the Fukushima Daiichi nuclear disaster in Japan on 11 March 2011 is reviewed and compared with the situation in Taiwan. The latter's nuclear disaster management system is examined with respect to three key variables: information; mobilisation; and inter-organisational cooperation. In-depth interviews with 10 policy stakeholders with different backgrounds serve as the research method. The results point up the need for improvement in all dimensions. In addition, they highlight three principal problems with the nuclear disaster management system: (i) it might not be possible to provide first-hand nuclear disaster information immediately to the communities surrounding the Maanshan facility in Pingtung County, southern Taiwan; (ii) the availability of medical resources for treating radiation in Hengchun Township is limited; and (iii) the inter-organisational relationships for addressing nuclear disasters need to be strengthened. Hence, cooperation among related organisations is necessary. © 2016 The Author(s). Disasters © Overseas Development Institute, 2016.

Status report on nuclear electric propulsion systems

NASA Technical Reports Server (NTRS)

Stearns, J. W.

1975-01-01

Progress in nuclear electric propulsion (NEP) systems for a multipayload multimission vehicle needed in both deep-space missions and a variety of geocentric missions is reviewed. The space system power level is a function of the initial launch vehicle mass, but developments in out-of-core nuclear thermionic direct conversion have broadened design options. Cost, design, and performance parameters are compared for reusable chemical space tugs and NEP reusable space tugs. Improvements in heat pipes, ion engines, and magnetoplasmadynamic arc jet thrust subsystems are discussed.

Nuclear Science Symposium, 19th, and Nuclear Power Systems Symposium, 4th, Miami, Fla., December 6-8, 1972, Proceedings.

NASA Technical Reports Server (NTRS)

1973-01-01

Major topics covered include radiation monitoring instrumentation, nuclear circuits and systems, biomedical applications of nuclear radiation in diagnosis and therapy, plasma research for fusion power, reactor control and instrumentation, nuclear power standards, and applications of digital computers in nuclear power plants. Systems and devices for space applications are described, including the Apollo alpha spectrometer, a position sensitive detection system for UV and X-ray photons, a 4500-volt electron multiplier bias supply for satellite use, spark chamber systems, proportional counters, and other devices. Individual items are announced in this issue.

Astrophysics space systems critical technology needs

NASA Technical Reports Server (NTRS)

Gartrell, C. F.

1982-01-01

This paper addresses an independent assessment of space system technology needs for future astrophysics flight programs contained within the NASA Space Systems Technology Model. The critical examination of the system needs for the approximately 30 flight programs in the model are compared to independent technology forecasts and possible technology deficits are discussed. These deficits impact the developments needed for spacecraft propulsion, power, materials, structures, navigation, guidance and control, sensors, communications and data processing. There are also associated impacts upon in-orbit assembly technology and space transportation systems. A number of under-utilized technologies are highlighted which could be exploited to reduce cost and enhance scientific return.

Implementing New Methods of Laser Marking of Items in the Nuclear Material Control and Accountability System at SSC RF-IPPE: An Automated Laser Marking System

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

Regoushevsky, V I; Tambovtsev, S D; Dvukhsherstnov, V G

2009-05-18

For over ten years SSC RF-IPPE, together with the US DOE National Laboratories, has been working on implementing automated control and accountability methods for nuclear materials and other items. Initial efforts to use adhesive bar codes or ones printed (painted) onto metal revealed that these methods were inconvenient and lacked durability under operational conditions. For NM disk applications in critical stands, there is the additional requirement that labels not affect the neutron characteristics of the critical assembly. This is particularly true for the many stainless-steel clad disks containing highly enriched uranium (HEU) and plutonium that are used at SSC RF-IPPEmore » for modeling nuclear power reactors. In search of an alternate method for labeling these disks, we tested several technological options, including laser marking and two-dimensional codes. As a result, the method of laser coloring was chosen in combination with Data Matrix ECC200 symbology. To implement laser marking procedures for the HEU disks and meet all the nuclear material (NM) handling standards and rules, IPPE staff, with U.S. technical and financial support, implemented an automated laser marking system; there are also specially developed procedures for NM movements during laser marking. For the laser marking station, a Zenith 10F system by Telesis Technologies (10 watt Ytterbium Fiber Laser and Merlin software) is used. The presentation includes a flowchart for the automated system and a list of specially developed procedures with comments. Among other things, approaches are discussed for human-factor considerations. To date, markings have been applied to numerous steel-clad HEU disks, and the work continues. In the future this method is expected to be applied to other MC&A items.« less

Manned space flight nuclear system safety. Volume 6: Space base nuclear system safety plan

NASA Technical Reports Server (NTRS)

1972-01-01

A qualitative identification of the steps required to assure the incorporation of radiological system safety principles and objectives into all phases of a manned space base program are presented. Specific areas of emphasis include: (1) radiological program management, (2) nuclear system safety plan implementation, (3) impact on program, and (4) summary of the key operation and design guidelines and requirements. The plan clearly indicates the necessity of considering and implementing radiological system safety recommendations as early as possible in the development cycle to assure maximum safety and minimize the impact on design and mission plans.

Systems aspects of a space nuclear reactor power system

NASA Technical Reports Server (NTRS)

Jaffe, L.; Fujita, T.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Grossman, M.; Bloomfield, H.; Heller, J.

1988-01-01

Various system aspects of a 300-kW nuclear reactor power system for spacecraft have been investigated. Special attention is given to the cases of a reusable OTV and a space-based radar. It is demonstrated that the stowed length of the power system is important to mission design, and that orbital storage for months to years may be needed for missions involving orbital assembly.

Rethinking healthcare as a safety--critical industry.

PubMed

Lwears, Robert

2012-01-01

The discipline of ergonomics, or human factors engineering, has made substantial contributions to both the development of a science of safety, and to the improvement of safety in a wide variety of hazardous industries, including nuclear power, aviation, shipping, energy extraction and refining, military operations, and finance. It is notable that healthcare, which in most advanced societies is a substantial sector of the economy (eg, 15% of US gross domestic product) and has been associated with large volumes of potentially preventable morbidity and mortality, has heretofore not been viewed as a safety-critical industry. This paper proposes that improving safety performance in healthcare must involve a re-envisioning of healthcare itself as a safety-critical industry, but one with considerable differences from most engineered safety-critical systems. This has implications both for healthcare, and for conceptions of safety-critical industries.

A primer on criticality safety

DOE PAGES

Costa, David A.; Cournoyer, Michael E.; Merhege, James F.; ...

2017-05-01

Criticality is the state of a nuclear chain reacting medium when the chain reaction is just self-sustaining (or critical). Criticality is dependent on nine interrelated parameters. Moreover, we design criticality safety controls in order to constrain these parameters to minimize fissions and maximize neutron leakage and absorption in other materials, which makes criticality more difficult or impossible to achieve. We present the consequences of criticality accidents are discussed, the nine interrelated parameters that combine to affect criticality are described, and criticality safety controls used to minimize the likelihood of a criticality accident are presented.

Lecture Notes on Criticality Safety Validation Using MCNP & Whisper

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

Brown, Forrest B.; Rising, Michael Evan; Alwin, Jennifer Louise

Training classes for nuclear criticality safety, MCNP documentation. The need for, and problems surrounding, validation of computer codes and data area considered first. Then some background for MCNP & Whisper is given--best practices for Monte Carlo criticality calculations, neutron spectra, S(α,β) thermal neutron scattering data, nuclear data sensitivities, covariance data, and correlation coefficients. Whisper is computational software designed to assist the nuclear criticality safety analyst with validation studies with the Monte Carlo radiation transport package MCNP. Whisper's methodology (benchmark selection – C k's, weights; extreme value theory – bias, bias uncertainty; MOS for nuclear data uncertainty – GLLS) and usagemore » are discussed.« less

Applied Nuclear Accountability Systems: A Case Study in the System Architecture and Development of NuMAC

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

Campbell, Andrea Beth

2004-07-01

This is a case study of the NuMAC nuclear accountability system developed at a private fuel fabrication facility. This paper investigates nuclear material accountability and safeguards by researching expert knowledge applied in the system design and development. Presented is a system developed to detect and deter the theft of weapons grade nuclear material. Examined is the system architecture that includes: issues for the design and development of the system; stakeholder issues; how the system was built and evolved; software design, database design, and development tool considerations; security and computing ethics. (author)

Instrumentation and Control Needs for Reliable Operation of Lunar Base Surface Nuclear Power Systems

NASA Technical Reports Server (NTRS)

Turso, James; Chicatelli, Amy; Bajwa, Anupa

2005-01-01

needed to enable this critical functionality of autonomous operation. It will be imperative to consider instrumentation and control requirements in parallel to system configuration development so as to identify control-related, as well as integrated system-related, problem areas early to avoid potentially expensive work-arounds . This paper presents an overview of the enabling technologies necessary for the development of reliable, autonomous lunar base nuclear power systems with an emphasis on system architectures and off-the-shelf algorithms rather than hardware. Autonomy needs are presented in the context of a hypothetical lunar base nuclear power system. The scenarios and applications presented are hypothetical in nature, based on information from open-literature sources, and only intended to provoke thought and provide motivation for the use of autonomous, intelligent control and diagnostics.

Shielding Development for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Caffrey, Jarvis A.; Gomez, Carlos F.; Scharber, Luke L.

2015-01-01

Radiation shielding analysis and development for the Nuclear Cryogenic Propulsion Stage (NCPS) effort is currently in progress and preliminary results have enabled consideration for critical interfaces in the reactor and propulsion stage systems. Early analyses have highlighted a number of engineering constraints, challenges, and possible mitigating solutions. Performance constraints include permissible crew dose rates (shared with expected cosmic ray dose), radiation heating flux into cryogenic propellant, and material radiation damage in critical components. Design strategies in staging can serve to reduce radiation scatter and enhance the effectiveness of inherent shielding within the spacecraft while minimizing the required mass of shielding in the reactor system. Within the reactor system, shield design is further constrained by the need for active cooling with minimal radiation streaming through flow channels. Material selection and thermal design must maximize the reliability of the shield to survive the extreme environment through a long duration mission with multiple engine restarts. A discussion of these challenges and relevant design strategies are provided for the mitigation of radiation in nuclear thermal propulsion.

Composite neutron absorbing coatings for nuclear criticality control

DOEpatents

Wright, Richard N.; Swank, W. David; Mizia, Ronald E.

2005-07-19

Thermal neutron absorbing composite coating materials and methods of applying such coating materials to spent nuclear fuel storage systems are provided. A composite neutron absorbing coating applied to a substrate surface includes a neutron absorbing layer overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. An optional bond coat layer can be formed on the substrate surface prior to forming the neutron absorbing layer. The neutron absorbing layer can include a neutron absorbing material, such as gadolinium oxide or gadolinium phosphate, dispersed in a metal alloy matrix. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process.

Nuclear reference materials to meet the changing needs of the global nuclear community

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

Martin, H.R.; Gradle, C.G.; Narayanan, U.I.

New Brunswick Laboratory (NBL) serves as the US Government`s Certifying Authority for nuclear reference materials and measurement calibration standards. In this role, NBL provides nuclear reference materials certified for chemical and/or isotopic compositions traceable to a nationally accepted, internationally compatible reference base. Emphasis is now changing as to the types of traceable nuclear reference materials needed as operations change within the Department of Energy (DOE) complex and at nuclear facilities around the world. Environmental and waste minimization issues, facilities and materials transitioning from processing to storage modes with corresponding changes in the types of measurements being performed, emphasis on requirementsmore » for characterization of waste materials, difficulties in transporting nuclear materials, and International factors, including International Atomic Energy Agency (IAEA) inspection of excess US nuclear materials, are all contributing influences. During these changing times, ft is critical that traceable reference materials be provided for calibration or validation of the performance of measurement systems. This paper will describe actions taken and planned to meet the changing reference material needs of the global nuclear community.« less

Nuclear system that burns its own wastes shows promise

NASA Technical Reports Server (NTRS)

Atchison, K.

1975-01-01

A nuclear fission energy system, capable of eliminating a significant amount of its radioactive wastes by burning them, is described. A theoretical investigation of this system conducted by computer analysis, is based on use of gaseous fuel nuclear reactors. Gaseous core reactors using a uranium plasma fuel are studied along with development for space propulsion.

Identity Verification Systems as a Critical Infrastructure

DTIC Science & Technology

2012-03-01

COVERED Master’s Thesis 4 . TITLE AND SUBTITLE Identity Verification Systems as a Critical Infrastructure 5. FUNDING NUMBERS 6. AUTHOR(S...43 3. Cybercrime .........................................................................................45 4 ...24 Figure 3. Uses of Fictitious or Stolen Identity ................................................................30 Figure 4

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.;

1986 Nuclear Science Symposium, 33rd, and 1986 Symposium on Nuclear Power Systems, 18th, Washington, DC, Oct. 29-31, 1986, Proceedings

NASA Technical Reports Server (NTRS)

Stubblefield, F. W. (Editor)

1987-01-01

Papers are presented on space, low-energy physics, and general nuclear science instrumentations. Topics discussed include data acquisition systems and circuits, nuclear medicine imaging and tomography, and nuclear radiation detectors. Consideration is given to high-energy physics instrumentation, reactor systems and safeguards, health physics instrumentation, and nuclear power systems.

A journey from nuclear criticality methods to high energy density radflow experiments

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

Urbatsch, Todd James

Los Alamos National Laboratory is a nuclear weapons laboratory supporting our nation's defense. In support of this mission is a high energy-density physics program in which we design and execute experiments to study radiationhydrodynamics phenomena and improve the predictive capability of our largescale multi-physics software codes on our big-iron computers. The Radflow project’s main experimental effort now is to understand why we haven't been able to predict opacities on Sandia National Laboratory's Z-machine. We are modeling an increasing fraction of the Z-machine's dynamic hohlraum to find multi-physics explanations for the experimental results. Further, we are building an entirely different opacitymore » platform on Lawrence Livermore National Laboratory's National Ignition Facility (NIF), which is set to get results early 2017. Will the results match our predictions, match the Z-machine, or give us something entirely different? The new platform brings new challenges such as designing hohlraums and spectrometers. The speaker will recount his history, starting with one-dimensional Monte Carlo nuclear criticality methods in graduate school, radiative transfer methods research and software development for his first 16 years at LANL, and, now, radflow technology and experiments. Who knew that the real world was more than just radiation transport? Experiments aren't easy and they are as saturated with politics as a presidential election, but they sure are fun.« less

A journey from nuclear criticality methods to high energy density radflow experiments

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

Urbatsch, Todd James

Los Alamos National Laboratory is a nuclear weapons laboratory supporting our nation's defense. In support of this mission is a high energy-density physics program in which we design and execute experiments to study radiationhydrodynamics phenomena and improve the predictive capability of our largescale multi-physics software codes on our big-iron computers. The Radflow project’s main experimental effort now is to understand why we haven't been able to predict opacities on Sandia National Laboratory's Z-machine. We are modeling an increasing fraction of the Z-machine's dynamic hohlraum to find multi-physics explanations for the experimental results. Further, we are building an entirely different opacitymore » platform on Lawrence Livermore National Laboratory's National Ignition Facility (NIF), which is set to get results early 2017. Will the results match our predictions, match the Z-machine, or give us something entirely different? The new platform brings new challenges such as designing hohlraums and spectrometers. The speaker will recount his history, starting with one-dimensional Monte Carlo nuclear criticality methods in graduate school, radiative transfer methods research and software development for his first 16 years at LANL, and, now, radflow technology and experiments. Who knew that the real world was more than just radiation transport? Experiments aren't easy, but they sure are fun.« less

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2007-07-12

done. Critics raised concerns about the implications of these policies for testing and new weapons. At present, Congress addresses nuclear weapon...future, but there are no plans to do so.’”7 Critics expressed concern about the implications of these policies for testing and new weapons. A statement by...opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”8 Another critic felt that

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2007-05-24

remain current. It indicated plans to reduce the time between a decision to conduct a nuclear test and the test itself, which has been done. Critics ...over the Summit,” Manila Bulletin, August 27, 2005. Critics expressed concern about the implications of these policies for testing and new weapons...force, seek the opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”8 Another critic

Alarm system for a nuclear control complex

DOEpatents

Scarola, Kenneth; Jamison, David S.; Manazir, Richard M.; Rescorl, Robert L.; Harmon, Daryl L.

1994-01-01

An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually. The integrated process status board (24) is at the apex of an information hierarchy that extends through four levels and provides access at each panel to the full display hierarchy. The control room panels are preferably of a modular construction, permitting the definition of inputs and outputs, the man machine interface, and the plant specific algorithms, to proceed in parallel with the fabrication of the panels, the installation of the equipment and the generic testing thereof.

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2007-11-01

critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation policy discouraged commercial nuclear fuel...perhaps the most critical question in this decade for strengthening the nuclear nonproliferation regime: how can access to sensitive fuel cycle...process can take advantage of the slight difference in atomic mass between 235U and 238U. The typical enrichment process requires about 10 lbs of uranium

Bounding criticality safety analyses for shipments of unconfigured spent nuclear fuel

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

Lichtenwalter, J.J.; Parks, C.V.

1998-06-01

In November 1996, a request was made to the US Department of Energy for a waiver for three shipments of spent nuclear fuel (SNF) from Oak Ridge National Laboratory (ORNL) to the Savannah River Site (SRS) in the US NRC certified BMI-1 cask (CoC 5957). Although the post-irradiation fissile mass (based on chemical assays) in each shipment was less than 800 g, a criticality safety analysis was needed because the pre-irradiation mass exceeded 800 g, the fissile material limit in the CoC. The analyses were performed on SNF consisting of aluminum-clad U{sub 3}O{sub 8}, UAl{sub x}, and U{sub 3}Si{sub 2}more » plates, fragments and pieces that had been irradiated at ORNL during the Reduced Enrichment Research and Test Reactor Program of the 1980s. The highlights of the approach used to analyze this unique SNF and the benefits of the waiver are presented in this paper.« less

Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk.

PubMed

Guttal, Vishwesha; Raghavendra, Srinivas; Goel, Nikunj; Hoarau, Quentin

2016-01-01

Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms.

Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk

PubMed Central

Hoarau, Quentin

2016-01-01

Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms. PMID:26761792

Network Randomization and Dynamic Defense for Critical Infrastructure Systems

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

Chavez, Adrian R.; Martin, Mitchell Tyler; Hamlet, Jason

2015-04-01

Critical Infrastructure control systems continue to foster predictable communication paths, static configurations, and unpatched systems that allow easy access to our nation's most critical assets. This makes them attractive targets for cyber intrusion. We seek to address these attack vectors by automatically randomizing network settings, randomizing applications on the end devices themselves, and dynamically defending these systems against active attacks. Applying these protective measures will convert control systems into moving targets that proactively defend themselves against attack. Sandia National Laboratories has led this effort by gathering operational and technical requirements from Tennessee Valley Authority (TVA) and performing research and developmentmore » to create a proof-of-concept solution. Our proof-of-concept has been tested in a laboratory environment with over 300 nodes. The vision of this project is to enhance control system security by converting existing control systems into moving targets and building these security measures into future systems while meeting the unique constraints that control systems face.« less

Critical Need for Plutonium and Uranium Isotopic Standards with Lower Uncertainties

DOE PAGES

Mathew, Kattathu Joseph; Stanley, Floyd E.; Thomas, Mariam R.; ...

2016-09-23

Certified reference materials (CRMs) traceable to national and international safeguards database are a critical prerequisite for ensuring that nuclear measurement systems are free of systematic biases. CRMs are used to validate measurement processes associated with nuclear analytical laboratories. Diverse areas related to nuclear safeguards are impacted by the quality of the CRM standards available to analytical laboratories. These include: nuclear forensics, radio-chronometry, national and international safeguards, stockpile stewardship, nuclear weapons infrastructure and nonproliferation, fuel fabrication, waste processing, radiation protection, and environmental monitoring. For the past three decades the nuclear community is confronted with the strange situation that improvements in measurementmore » data quality resulting from the improved accuracy and precision achievable with modern multi-collector mass spectrometers could not be fully exploited due to large uncertainties associated with CRMs available from New Brunswick Laboratory (NBL) that are used for instrument calibration and measurement control. Similar conditions prevail for both plutonium and uranium isotopic standards and for impurity element standards in uranium matrices. Herein, the current status of U and Pu isotopic standards available from NBL is reviewed. Critical areas requiring improvement in the quality of the nuclear standards to enable the U. S. and international safeguards community to utilize the full potential of modern multi-collector mass spectrometer instruments are highlighted.« less

Critical Need for Plutonium and Uranium Isotopic Standards with Lower Uncertainties

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

Mathew, Kattathu Joseph; Stanley, Floyd E.; Thomas, Mariam R.

Certified reference materials (CRMs) traceable to national and international safeguards database are a critical prerequisite for ensuring that nuclear measurement systems are free of systematic biases. CRMs are used to validate measurement processes associated with nuclear analytical laboratories. Diverse areas related to nuclear safeguards are impacted by the quality of the CRM standards available to analytical laboratories. These include: nuclear forensics, radio-chronometry, national and international safeguards, stockpile stewardship, nuclear weapons infrastructure and nonproliferation, fuel fabrication, waste processing, radiation protection, and environmental monitoring. For the past three decades the nuclear community is confronted with the strange situation that improvements in measurementmore » data quality resulting from the improved accuracy and precision achievable with modern multi-collector mass spectrometers could not be fully exploited due to large uncertainties associated with CRMs available from New Brunswick Laboratory (NBL) that are used for instrument calibration and measurement control. Similar conditions prevail for both plutonium and uranium isotopic standards and for impurity element standards in uranium matrices. Herein, the current status of U and Pu isotopic standards available from NBL is reviewed. Critical areas requiring improvement in the quality of the nuclear standards to enable the U. S. and international safeguards community to utilize the full potential of modern multi-collector mass spectrometer instruments are highlighted.« less

Heisenberg and the critical mass

NASA Astrophysics Data System (ADS)

Bernstein, Jeremy

2002-09-01

An elementary treatment of the critical mass used in nuclear weapons is presented and applied to an analysis of the wartime activities of the German nuclear program. In particular, the work of Werner Heisenberg based on both wartime and postwar documents is discussed.

Nuclear light bulb

NASA Technical Reports Server (NTRS)

Latham, Tom

1991-01-01

The nuclear light bulb engine is a closed cycle concept. The nuclear light bulb concept provides containment by keeping the nuclear fuel fluid mechanically suspended in a cylindrical geometry. Thermal heat passes through an internally cooled, fused-silica, transparent wall and heats hydrogen propellant. The seeded hydrogen propellant absorbs radiant energy and is expanded through a nozzle. Internal moderation was used in the configuration which resulted in a reduced critical density requirement. This result was supported by criticality experiments. A reference engine was designed that had seven cells and was sized to fit in what was then predicted to be the shuttle bay mass and volume limitations. There were studies done of nozzle throat cooling schemes to remove the radiant heat. Elements of the nuclear light bulb program included closed loop critical assembly tests done at Los Alamos with UF6 confined by argon buffer gas. It was shown that the fuel region could be seeded with constituents that would block UV radiation from the uranium plasma. A combination of calculations and experiments showed that internal moderation produced a critical mass reduction. Other aspects of the research are presented.

Critical experiments at Sandia National Laboratories : technical meeting on low-power critical facilities and small reactors.

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

Harms, Gary A.; Ford, John T.; Barber, Allison Delo

2010-11-01

Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-IIImore » is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide

Nuclear Thermal Rocket - Arc Jet Integrated System Model

NASA Technical Reports Server (NTRS)

Taylor, Brian D.; Emrich, William

2016-01-01

In the post-shuttle era, space exploration is moving into a new regime. Commercial space flight is in development and is planned to take on much of the low earth orbit space flight missions. With the development of a heavy lift launch vehicle, the Space Launch, System, NASA has become focused on deep space exploration. Exploration into deep space has traditionally been done with robotic probes. More ambitious missions such as manned missions to asteroids and Mars will require significant technology development. Propulsion system performance is tied to the achievability of these missions and the requirements of other developing technologies that will be required. Nuclear thermal propulsion offers a significant improvement over chemical propulsion while still achieving high levels of thrust. Opportunities exist; however, to build upon what would be considered a standard nuclear thermal engine to attain improved performance, thus further enabling deep space missions. This paper discuss the modeling of a nuclear thermal system integrated with an arc jet to further augment performance. The performance predictions and systems impacts are discussed.

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.

31 CFR 800.209 - Critical technologies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Critical technologies. 800.209 Section... TAKEOVERS BY FOREIGN PERSONS Definitions § 800.209 Critical technologies. The term critical technologies..., nuclear nonproliferation, or missile technology), as well as those that are controlled for reasons of...

31 CFR 800.209 - Critical technologies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Critical technologies. 800.209 Section... TAKEOVERS BY FOREIGN PERSONS Definitions § 800.209 Critical technologies. The term critical technologies..., nuclear nonproliferation, or missile technology), as well as those that are controlled for reasons of...

31 CFR 800.209 - Critical technologies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Critical technologies. 800.209 Section... TAKEOVERS BY FOREIGN PERSONS Definitions § 800.209 Critical technologies. The term critical technologies..., nuclear nonproliferation, or missile technology), as well as those that are controlled for reasons of...

31 CFR 800.209 - Critical technologies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Critical technologies. 800.209 Section... TAKEOVERS BY FOREIGN PERSONS Definitions § 800.209 Critical technologies. The term critical technologies..., nuclear nonproliferation, or missile technology), as well as those that are controlled for reasons of...

Security for safety critical space borne systems

NASA Technical Reports Server (NTRS)

Legrand, Sue

1987-01-01

The Space Station contains safety critical computer software components in systems that can affect life and vital property. These components require a multilevel secure system that provides dynamic access control of the data and processes involved. A study is under way to define requirements for a security model providing access control through level B3 of the Orange Book. The model will be prototyped at NASA-Johnson Space Center.

Nuclear criticality safety evaluation of the passage of decontaminated salt solution from the ITP filters into tank 50H for interim storage

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

Hobbs, D.T.; Davis, J.R.

This report assesses the nuclear criticality safety associated with the decontaminated salt solution after passing through the In-Tank Precipitation (ITP) filters, through the stripper columns and into Tank 50H for interim storage until transfer to the Saltstone facility. The criticality safety basis for the ITP process is documented. Criticality safety in the ITP filtrate has been analyzed under normal and process upset conditions. This report evaluates the potential for criticality due to the precipitation or crystallization of fissionable material from solution and an ITP process filter failure in which insoluble material carryover from salt dissolution is present. It is concludedmore » that no single inadvertent error will cause criticality and that the process will remain subcritical under normal and credible abnormal conditions.« less

Nuclear thermal rocket workshop reference system Rover/NERVA

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.

1991-01-01

The Rover/NERVA engine system is to be used as a reference, against which each of the other concepts presented in the workshop will be compared. The following topics are reviewed: the operational characteristics of the nuclear thermal rocket (NTR); the accomplishments of the Rover/NERVA programs; and performance characteristics of the NERVA-type systems for both Mars and lunar mission applications. Also, the issues of ground testing, NTR safety, NASA's nuclear propulsion project plans, and NTR development cost estimates are briefly discussed.

JANIS: NEA JAva-based Nuclear Data Information System

NASA Astrophysics Data System (ADS)

Soppera, Nicolas; Bossant, Manuel; Cabellos, Oscar; Dupont, Emmeric; Díez, Carlos J.

2017-09-01

JANIS (JAva-based Nuclear Data Information System) software is developed by the OECD Nuclear Energy Agency (NEA) Data Bank to facilitate the visualization and manipulation of nuclear data, giving access to evaluated nuclear data libraries, such as ENDF, JEFF, JENDL, TENDL etc., and also to experimental nuclear data (EXFOR) and bibliographical references (CINDA). It is available as a standalone Java program, downloadable and distributed on DVD and also a web application available on the NEA website. One of the main new features in JANIS is the scripting capability via command line, which notably automatizes plots generation and permits automatically extracting data from the JANIS database. Recent NEA software developments rely on these JANIS features to access nuclear data, for example the Nuclear Data Sensitivity Tool (NDaST) makes use of covariance data in BOXER and COVERX formats, which are retrieved from the JANIS database. New features added in this version of the JANIS software are described along this paper with some examples.

Cultural Awareness in Nuclear Security Programs: A Critical Link

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

Nasser, Al-Sharif Nasser bin; Auda, Jasmine; Bachner, Katherine

Nuclear security programs that offer training and capacity building opportunities to practitioners working in nuclear facilities play a central role in strengthening the global nuclear security architecture. There is often a significant divide, however, between both the development of these programs and their implementation, and between the programs’ intended and actual outcomes. This article argues that this disconnect can often be attributed to an absence of cultural awareness and an inability for internationally-designed programs to effectively resonate with local audiences. Furthermore, the importance of the role of cultural awareness in implementing nuclear security programs will be assessed, and its applicationsmore » in the Jordanian context will be presented.« less

Cultural Awareness in Nuclear Security Programs: A Critical Link

DOE PAGES

Nasser, Al-Sharif Nasser bin; Auda, Jasmine; Bachner, Katherine

2016-11-20

Nuclear security programs that offer training and capacity building opportunities to practitioners working in nuclear facilities play a central role in strengthening the global nuclear security architecture. There is often a significant divide, however, between both the development of these programs and their implementation, and between the programs’ intended and actual outcomes. This article argues that this disconnect can often be attributed to an absence of cultural awareness and an inability for internationally-designed programs to effectively resonate with local audiences. Furthermore, the importance of the role of cultural awareness in implementing nuclear security programs will be assessed, and its applicationsmore » in the Jordanian context will be presented.« less

Digital Signal Processing Methods for Safety Systems Employed in Nuclear Power Industry

NASA Astrophysics Data System (ADS)

Popescu, George

Some of the major safety concerns in the nuclear power industry focus on the readiness of nuclear power plant safety systems to respond to an abnormal event, the security of special nuclear materials in used nuclear fuels, and the need for physical security to protect personnel and reactor safety systems from an act of terror. Routine maintenance and tests of all nuclear reactor safety systems are performed on a regular basis to confirm the ability of these systems to operate as expected. However, these tests do not determine the reliability of these safety systems and whether the systems will perform for the duration of an accident and whether they will perform their tasks without failure after being engaged. This research has investigated the progression of spindle asynchronous error motion determined from spindle accelerations to predict bearings failure onset. This method could be applied to coolant pumps that are essential components of emergency core cooling systems at all nuclear power plants. Recent security upgrades mandated by the Nuclear Regulatory Commission and the Department of Homeland Security have resulted in implementation of multiple physical security barriers around all of the commercial and research nuclear reactors in the United States. A second part of this research attempts to address an increased concern about illegal trafficking of Special Nuclear Materials (SNM). This research describes a multi element scintillation detector system designed for non - invasive (passive) gamma ray surveillance for concealed SNM that may be within an area or sealed in a package, vehicle or shipping container. Detection capabilities of the system were greatly enhanced through digital signal processing, which allows the combination of two very powerful techniques: 1) Compton Suppression (CS) and 2) Pulse Shape Discrimination (PSD) with less reliance on complicated analog instrumentation.

Use of virtual reality gaming systems for children who are critically ill.

PubMed

Salem, Yasser; Elokda, Ahmed

2014-01-01

Children who are critically ill are frequently viewed as "too sick" to tolerate physical activity. As a result, these children often fail to develop strength or cardiovascular endurance as compared to typically developing children. Previous reports have shown that early participation in physical activity in is safe and feasible for patients who are critically ill and may result in a shorter length of stay and improved functional outcomes. The use of the virtual reality gaming systems has become a popular form of therapy for children with disabilities and has been supported by a growing body of evidence substantiating its effectiveness with this population. The use of the virtual reality gaming systems in pediatric rehabilitation provides the children with opportunity to participate in an exercise program that is fun, enjoyable, playful, and at the same time beneficial. The integration of those systems in rehabilitation of children who are critically ill is appealing and has the potential to offer the possibility of enhancing physical activities. The lack of training studies involving children who are critically ill makes it difficult to set guidelines on the recommended physical activities and virtual reality gaming systems that is needed to confer health benefits. Several considerations should be taken into account before recommended virtual reality gaming systems as a training program for children who are critically ill. This article highlighted guidelines, limitations and challenges that need to be considered when designing exercise program using virtual reality gaming systems for critically ill children. This information is helpful given the popular use of virtual reality gaming systems in rehabilitation, particularly in children who are critically ill.

System Dynamics Approach for Critical Infrastructure and Decision Support. A Model for a Potable Water System.

NASA Astrophysics Data System (ADS)

Pasqualini, D.; Witkowski, M.

2005-12-01

The Critical Infrastructure Protection / Decision Support System (CIP/DSS) project, supported by the Science and Technology Office, has been developing a risk-informed Decision Support System that provides insights for making critical infrastructure protection decisions. The system considers seventeen different Department of Homeland Security defined Critical Infrastructures (potable water system, telecommunications, public health, economics, etc.) and their primary interdependencies. These infrastructures have been modeling in one model called CIP/DSS Metropolitan Model. The modeling approach used is a system dynamics modeling approach. System dynamics modeling combines control theory and the nonlinear dynamics theory, which is defined by a set of coupled differential equations, which seeks to explain how the structure of a given system determines its behavior. In this poster we present a system dynamics model for one of the seventeen critical infrastructures, a generic metropolitan potable water system (MPWS). Three are the goals: 1) to gain a better understanding of the MPWS infrastructure; 2) to identify improvements that would help protect MPWS; and 3) to understand the consequences, interdependencies, and impacts, when perturbations occur to the system. The model represents raw water sources, the metropolitan water treatment process, storage of treated water, damage and repair to the MPWS, distribution of water, and end user demand, but does not explicitly represent the detailed network topology of an actual MPWS. The MPWS model is dependent upon inputs from the metropolitan population, energy, telecommunication, public health, and transportation models as well as the national water and transportation models. We present modeling results and sensitivity analysis indicating critical choke points, negative and positive feedback loops in the system. A general scenario is also analyzed where the potable water system responds to a generic disruption.

Nuclear reference materials to meet the changing needs of the global nuclear community

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

Martin, H.R.; Gradle, C.G.; Narayanan, U.I.

New Brunswick Laboratory (NBL) serves as the U.S. Government`s certifying authority for nuclear reference materials and measurement calibration standards. In this role, NBL provides nuclear reference materials certified for chemical and/or isotopic compositions traceable to a nationally accepted, internationally compatible reference base. Emphasis is now changing as to the types of traceable nuclear reference materials needed as operations change within the Department of Energy complex and at nuclear facilities around the world. New challenges include: environmental and waste minimization issues, facilities and materials transitioning from processing to storage modes with corresponding changes in the types of measurements being performed, emphasismore » on requirements for characterization of waste materials, and difficulties in transporting nuclear materials and international factors, including IAEA influences. During these changing times, it is critical that traceable reference materials be provided for calibration or validation of the performance of measurement systems. This paper will describe actions taken and planned to meet the changing reference material needs of the global nuclear community.« less

Critical Frequency in Nuclear Chiral Rotation

NASA Astrophysics Data System (ADS)

Olbratowski, P.; Dobaczewski, J.; Dudek, J.; Płóciennik, W.

2004-07-01

Self-consistent solutions for the so-called planar and chiral rotational bands in 132La are obtained for the first time within the Skyrme-Hartree-Fock cranking approach. It is suggested that the chiral rotation cannot exist below a certain critical frequency which under the approximations used is estimated as ℏωcrit≈0.5 0.6 MeV. However, the exact values of ℏωcrit may vary, to an extent, depending on the microscopic model used, in particular, through the pairing correlations and/or calculated equilibrium deformations. The existence of the critical frequency is explained in terms of a simple classical model of two gyroscopes coupled to a triaxial rigid body.

Critical (of) Issues in Real-Time Systems.

DTIC Science & Technology

1988-05-03

IACCESON 11 T IT LE (Include Security Classification) Cr it ic, (of) issues in real .- time systems A Position Paper 12 PERPSONAL AU THOR(S) Fr ed B...are obsolete %0%’ 4.’.C %" Critical (of) issues in real - time systems ’ • "A Position Paper Acc, son For NTIS R& DTrC TAB May 3, 1988 Uyjannotuce~d...m . 2C:. r Ithaca, New York 14853 Dist 1 -.1 g- It is time to place the development of real - time systems on a firm scientific basis. Unlike other

Soviet short-range nuclear forces: flexible response or flexible aggression. Student essay

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

Smith, T.R.

1987-03-23

This essay takes a critical look at Soviet short-range nuclear forces in an effort to identify Soviet capabilities to fight a limited nuclear war with NATO. From an analysis of Soviet military art, weapon-system capabilities and tactics, the author concludes that the Soviets have developed a viable limited-nuclear-attack option. Unless NATO reacts to this option, the limited nuclear attack may become favored Soviet option and result in the rapid defeat of NATO.

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2008-01-20

critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation policy discouraged commercial nuclear fuel...have U.S. government officials. However, the case of Iran raises perhaps the most critical question in this decade for strengthening the nuclear...slight difference in atomic mass between 235U and 238U. The typical enrichment process requires about 10 lbs of uranium U3O8 to produce 1 lb of low

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

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

Effects of the Application of the New Nuclear Data Library ENDF/B to the Criticality Analysis of AP1000

NASA Astrophysics Data System (ADS)

Kuntoro, Iman; Sembiring, T. M.; Susilo, Jati; Deswandri; Sunaryo, G. R.

2018-02-01

Calculations of criticality of the AP1000 core due to the use of new edition of nuclear data library namely ENDF/B-VII and ENDF/B-VII.1 have been done. This work is aimed to know the accuracy of ENDF/B-VII.1 compared to ENDF/B-VII and ENDF/B-VI.8. in determining the criticality parameter of AP1000. Analysis ws imposed to core at cold zero power (CZP) conditions. The calculations have been carried out by means of MCNP computer code for 3 dimension geometry. The results show that criticality parameter namely effective multiplication factor of the AP1000 core are higher than that ones resulted from ENDF/B-VI.8 with relative differences of 0.39% for application of ENDF/B-VII and of 0.34% for application of ENDF/B-VII.1.

Parametric Optimization of Some Critical Operating System Functions--An Alternative Approach to the Study of Operating Systems Design

ERIC Educational Resources Information Center

Sobh, Tarek M.; Tibrewal, Abhilasha

2006-01-01

Operating systems theory primarily concentrates on the optimal use of computing resources. This paper presents an alternative approach to teaching and studying operating systems design and concepts by way of parametrically optimizing critical operating system functions. Detailed examples of two critical operating systems functions using the…

Sleep dynamics: A self-organized critical system

NASA Astrophysics Data System (ADS)

Comte, J. C.; Ravassard, P.; Salin, P. A.

2006-05-01

In psychiatric and neurological diseases, sleep is often perturbed. Moreover, recent works on humans and animals tend to show that sleep plays a strong role in memory processes. Reciprocally, sleep dynamics following a learning task is modified [Hubert , Nature (London) 02663, 1 (2004), Peigneux , Neuron 44, 535 (2004)]. However, sleep analysis in humans and animals is often limited to the total sleep and wake duration quantification. These two parameters are not fully able to characterize the sleep dynamics. In mammals sleep presents a complex organization with an alternation of slow wave sleep (SWS) and paradoxical sleep (PS) episodes. Moreover, it has been shown recently that these sleep episodes are frequently interrupted by micro-arousal (without awakening). We present here a detailed analysis of the basal sleep properties emerging from the mechanisms underlying the vigilance states alternation in an animal model. These properties present a self-organized critical system signature and reveal the existence of two W, two SWS, and a PS structure exhibiting a criticality as met in sand piles. We propose a theoretical model of the sleep dynamics based on several interacting neuronal populations. This new model of sleep dynamics presents the same properties as experimentally observed, and explains the variability of the collected data. This experimental and theoretical study suggests that sleep dynamics shares several common features with critical systems.

ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

NASA Astrophysics Data System (ADS)

Chadwick, M. B.; Obložinský, P.; Herman, M.; Greene, N. M.; McKnight, R. D.; Smith, D. L.; Young, P. G.; MacFarlane, R. E.; Hale, G. M.; Frankle, S. C.; Kahler, A. C.; Kawano, T.; Little, R. C.; Madland, D. G.; Moller, P.; Mosteller, R. D.; Page, P. R.; Talou, P.; Trellue, H.; White, M. C.; Wilson, W. B.; Arcilla, R.; Dunford, C. L.; Mughabghab, S. F.; Pritychenko, B.; Rochman, D.; Sonzogni, A. A.; Lubitz, C. R.; Trumbull, T. H.; Weinman, J. P.; Brown, D. A.; Cullen, D. E.; Heinrichs, D. P.; McNabb, D. P.; Derrien, H.; Dunn, M. E.; Larson, N. M.; Leal, L. C.; Carlson, A. D.; Block, R. C.; Briggs, J. B.; Cheng, E. T.; Huria, H. C.; Zerkle, M. L.; Kozier, K. S.; Courcelle, A.; Pronyaev, V.; van der Marck, S. C.

2006-12-01

We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes, based on experimental data and theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, 6Li, 10B, Au and for 235,238U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced evaluations up to 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; (10) New methods for uncertainties and covariances, together with covariance evaluations for some sample cases; and (11) New actinide fission energy deposition. The paper provides an overview of this library, consisting of 14 sublibraries in the same ENDF-6 format as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched uranium thermal assemblies is removed; (b) The 238U and 208Pb reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good

Nuclear reactor sealing system

DOEpatents

McEdwards, James A.

1983-01-01

A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.

'One physical system': Tansley's ecosystem as Earth's critical zone.

PubMed

Richter, Daniel deB; Billings, Sharon A

2015-05-01

Integrative concepts of the biosphere, ecosystem, biogeocenosis and, recently, Earth's critical zone embrace scientific disciplines that link matter, energy and organisms in a systems-level understanding of our remarkable planet. Here, we assert the congruence of Tansley's (1935) venerable ecosystem concept of 'one physical system' with Earth science's critical zone. Ecosystems and critical zones are congruent across spatial-temporal scales from vegetation-clad weathering profiles and hillslopes, small catchments, landscapes, river basins, continents, to Earth's whole terrestrial surface. What may be less obvious is congruence in the vertical dimension. We use ecosystem metabolism to argue that full accounting of photosynthetically fixed carbon includes respiratory CO₂ and carbonic acid that propagate to the base of the critical zone itself. Although a small fraction of respiration, the downward diffusion of CO₂ helps determine rates of soil formation and, ultimately, ecosystem evolution and resilience. Because life in the upper portions of terrestrial ecosystems significantly affects biogeochemistry throughout weathering profiles, the lower boundaries of most terrestrial ecosystems have been demarcated at depths too shallow to permit a complete understanding of ecosystem structure and function. Opportunities abound to explore connections between upper and lower components of critical-zone ecosystems, between soils and streams in watersheds, and between plant-derived CO₂ and deep microbial communities and mineral weathering. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Nuclear Hybrid Energy System Model Stability Testing

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

Greenwood, Michael Scott; Cetiner, Sacit M.; Fugate, David W.

2017-04-01

A Nuclear Hybrid Energy System (NHES) uses a nuclear reactor as the basic power generation unit, and the power generated is used by multiple customers as combinations of thermal power or electrical power. The definition and architecture of a particular NHES can be adapted based on the needs and opportunities of different localities and markets. For example, locations in need of potable water may be best served by coupling a desalination plant to the NHES. Similarly, a location near oil refineries may have a need for emission-free hydrogen production. Using the flexible, multi-domain capabilities of Modelica, Argonne National Laboratory, Idahomore » National Laboratory, and Oak Ridge National Laboratory are investigating the dynamics (e.g., thermal hydraulics and electrical generation/consumption) and cost of a hybrid system. This paper examines the NHES work underway, emphasizing the control system developed for individual subsystems and the overall supervisory control system.« less

Traceability of Software Safety Requirements in Legacy Safety Critical Systems

NASA Technical Reports Server (NTRS)

Hill, Janice L.

2007-01-01

How can traceability of software safety requirements be created for legacy safety critical systems? Requirements in safety standards are imposed most times during contract negotiations. On the other hand, there are instances where safety standards are levied on legacy safety critical systems, some of which may be considered for reuse for new applications. Safety standards often specify that software development documentation include process-oriented and technical safety requirements, and also require that system and software safety analyses are performed supporting technical safety requirements implementation. So what can be done if the requisite documents for establishing and maintaining safety requirements traceability are not available?

An End-To-End Test of A Simulated Nuclear Electric Propulsion System

NASA Technical Reports Server (NTRS)

VanDyke, Melissa; Hrbud, Ivana; Goddfellow, Keith; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

The Safe Affordable Fission Engine (SAFE) test series addresses Phase I Space Fission Systems issues in it particular non-nuclear testing and system integration issues leading to the testing and non-nuclear demonstration of a 400-kW fully integrated flight unit. The first part of the SAFE 30 test series demonstrated operation of the simulated nuclear core and heat pipe system. Experimental data acquired in a number of different test scenarios will validate existing computational models, demonstrated system flexibility (fast start-ups, multiple start-ups/shut downs), simulate predictable failure modes and operating environments. The objective of the second part is to demonstrate an integrated propulsion system consisting of a core, conversion system and a thruster where the system converts thermal heat into jet power. This end-to-end system demonstration sets a precedent for ground testing of nuclear electric propulsion systems. The paper describes the SAFE 30 end-to-end system demonstration and its subsystems.

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.

Systems modeling and simulation applications for critical care medicine

PubMed Central

2012-01-01

Critical care delivery is a complex, expensive, error prone, medical specialty and remains the focal point of major improvement efforts in healthcare delivery. Various modeling and simulation techniques offer unique opportunities to better understand the interactions between clinical physiology and care delivery. The novel insights gained from the systems perspective can then be used to develop and test new treatment strategies and make critical care delivery more efficient and effective. However, modeling and simulation applications in critical care remain underutilized. This article provides an overview of major computer-based simulation techniques as applied to critical care medicine. We provide three application examples of different simulation techniques, including a) pathophysiological model of acute lung injury, b) process modeling of critical care delivery, and c) an agent-based model to study interaction between pathophysiology and healthcare delivery. Finally, we identify certain challenges to, and opportunities for, future research in the area. PMID:22703718

Time-critical multirate scheduling using contemporary real-time operating system services

NASA Technical Reports Server (NTRS)

Eckhardt, D. E., Jr.

1983-01-01

Although real-time operating systems provide many of the task control services necessary to process time-critical applications (i.e., applications with fixed, invariant deadlines), it may still be necessary to provide a scheduling algorithm at a level above the operating system in order to coordinate a set of synchronized, time-critical tasks executing at different cyclic rates. The scheduling requirements for such applications and develops scheduling algorithms using services provided by contemporary real-time operating systems.

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.

Application of Nuclear Magnetic Resonance and Hybrid Methods to Structure Determination of Complex Systems.

PubMed

Prischi, Filippo; Pastore, Annalisa

2016-01-01

The current main challenge of Structural Biology is to undertake the structure determination of increasingly complex systems in the attempt to better understand their biological function. As systems become more challenging, however, there is an increasing demand for the parallel use of more than one independent technique to allow pushing the frontiers of structure determination and, at the same time, obtaining independent structural validation. The combination of different Structural Biology methods has been named hybrid approaches. The aim of this review is to critically discuss the most recent examples and new developments that have allowed structure determination or experimentally-based modelling of various molecular complexes selecting them among those that combine the use of nuclear magnetic resonance and small angle scattering techniques. We provide a selective but focused account of some of the most exciting recent approaches and discuss their possible further developments.

ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

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

Chadwick, M B; Oblozinsky, P; Herman, M

2006-10-02

reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good agreement for simulations of highly enriched uranium assemblies is preserved; (d) The underprediction of fast criticality of {sup 233,235}U and {sup 239}Pu assemblies is removed; and (e) The intermediate spectrum critical assemblies are predicted more accurately. We anticipate that the new library will play an important role in nuclear technology applications, including transport simulations supporting national security, nonproliferation, advanced reactor and fuel cycle concepts, criticality safety, medicine, space applications, nuclear astrophysics, and nuclear physics facility design. The ENDF/B-VII.0 library is archived at the National Nuclear Data Center, BNL. The complete library, or any part of it, may be retrieved from www.nndc.bnl.gov.« less

Nuclear Hybrid Energy Systems Initial Integrated Case Study Development and Analysis

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

Harrison, Thomas J.; Greenwood, Michael Scott

The US Department of Energy Office of Nuclear Energy established the Nuclear Hybrid Energy System (NHES) project to develop a systematic, rigorous, technically accurate set of methods to model, analyze, and optimize the integration of dispatchable nuclear, fossil, and electric storage with an industrial customer. Ideally, the optimized integration of these systems will provide economic and operational benefits to the overall system compared to independent operation, and it will enhance the stability and responsiveness of the grid as intermittent, nondispatchable, renewable resources provide a greater share of grid power.

Critical scaling of a jammed system after a quench of temperature.

PubMed

Otsuki, Michio; Hayakawa, Hisao

2012-09-01

Critical behavior of soft repulsive particles after quench of temperature near the jamming transition is numerically investigated. It is found that the plateau of the mean-square displacement of tracer particles and the pressure satisfy critical scaling laws. The critical density for the jamming transition depends on the protocol to prepare the system, while the values of the critical exponents which are consistent with the prediction of a phenomenology are independent of the protocol.

Identification of the low-energy excitations in a quantum critical system

NASA Astrophysics Data System (ADS)

Heitmann, Tom; Lamsal, Jagat; Watson, Shannon; Erwin, Ross; Chen, Wangchun; Zhao, Yang; Montfrooij, Wouter

2017-05-01

We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.24)2Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R) (2006)].

Cryogenic Fluid Management Technology Development for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Taylor, B. D.; Caffrey, J.; Hedayat, A.; Stephens, J.; Polsgrove, R.

2015-01-01

Cryogenic fluid management technology is critical to the success of future nuclear thermal propulsion powered vehicles and long duration missions. This paper discusses current capabilities in key technologies and their development path. The thermal environment, complicated from the radiation escaping a reactor of a nuclear thermal propulsion system, is examined and analysis presented. The technology development path required for maintaining cryogenic propellants in this environment is reviewed. This paper is intended to encourage and bring attention to the cryogenic fluid management technologies needed to enable nuclear thermal propulsion powered deep space missions.

Low Pressure Nuclear Thermal Rocket (LPNTR) concept

NASA Technical Reports Server (NTRS)

Ramsthaler, J. H.

1991-01-01

A background and a description of the low pressure nuclear thermal system are presented. Performance, mission analysis, development, critical issues, and some conclusions are discussed. The following subject areas are covered: LPNTR's inherent advantages in critical NTR requirement; reactor trade studies; reference LPNTR; internal configuration and flow of preliminary LPNTR; particle bed fuel assembly; preliminary LPNTR neutronic study results; multiple LPNTR engine concept; tank and engine configuration for mission analysis; LPNTR reliability potential; LPNTR development program; and LPNTR program costs.

Identification of critical regions in human SAMHD1 required for nuclear localization and Vpx-mediated degradation.

PubMed

Guo, Haoran; Wei, Wei; Wei, Zhenhong; Liu, Xianjun; Evans, Sean L; Yang, Weiming; Wang, Hong; Guo, Ying; Zhao, Ke; Zhou, Jian-Ying; Yu, Xiao-Fang

2013-01-01

The sterile alpha motif (SAM) and HD domain-containing protein-1 (SAMHD1) inhibits the infection of resting CD4+ T cells and myeloid cells by human and related simian immunodeficiency viruses (HIV and SIV). Vpx inactivates SAMHD1 by promoting its proteasome-dependent degradation through an interaction with CRL4 (DCAF1) E3 ubiquitin ligase and the C-terminal region of SAMHD1. However, the determinants in SAMHD1 that are required for Vpx-mediated degradation have not been well characterized. SAMHD1 contains a classical nuclear localization signal (NLS), and NLS point mutants are cytoplasmic and resistant to Vpx-mediated degradation. Here, we demonstrate that NLS-mutant SAMHD1 K11A can be rescued by wild-type SAMHD1, restoring its nuclear localization; consequently, SAMHD1 K11A became sensitive to Vpx-mediated degradation in the presence of wild-type SAMHD1. Surprisingly, deletion of N-terminal regions of SAMHD1, including the classical NLS, generated mutant SAMHD1 proteins that were again sensitive to Vpx-mediated degradation. Unlike SAMHD1 K11A, these deletion mutants could be detected in the nucleus. Interestingly, NLS-defective SAMHD1 could still bind to karyopherin-β1 and other nuclear proteins. We also determined that the linker region between the SAM and HD domain and the HD domain itself is important for Vpx-mediated degradation but not Vpx interaction. Thus, SAMHD1 contains an additional nuclear targeting mechanism in addition to the classical NLS. Our data indicate that multiple regions in SAMHD1 are critical for Vpx-mediated nuclear degradation and that association with Vpx is not sufficient for Vpx-mediated degradation of SAMHD1. Since the linker region and HD domain may be involved in SAMHD1 multimerization, our results suggest that SAMHD1 multimerization may be required for Vpx-mediation degradation.

10 CFR 76.89 - Criticality accident requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Criticality accident requirements. 76.89 Section 76.89 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.89 Criticality accident requirements. (a) The Corporation must maintain and operate a criticality monitoring and...

10 CFR 76.89 - Criticality accident requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Criticality accident requirements. 76.89 Section 76.89 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.89 Criticality accident requirements. (a) The Corporation must maintain and operate a criticality monitoring and...

10 CFR 76.89 - Criticality accident requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Criticality accident requirements. 76.89 Section 76.89 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.89 Criticality accident requirements. (a) The Corporation must maintain and operate a criticality monitoring and...

10 CFR 76.89 - Criticality accident requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Criticality accident requirements. 76.89 Section 76.89 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.89 Criticality accident requirements. (a) The Corporation must maintain and operate a criticality monitoring and...

10 CFR 76.89 - Criticality accident requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Criticality accident requirements. 76.89 Section 76.89 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.89 Criticality accident requirements. (a) The Corporation must maintain and operate a criticality monitoring and...

10 CFR 70.24 - Criticality accident requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Criticality accident requirements. 70.24 Section 70.24... Applications § 70.24 Criticality accident requirements. (a) Each licensee authorized to possess special nuclear...-sensitive radiation detectors which will energize clearly audible alarm signals if accidental criticality...

10 CFR 70.24 - Criticality accident requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Criticality accident requirements. 70.24 Section 70.24... Applications § 70.24 Criticality accident requirements. (a) Each licensee authorized to possess special nuclear...-sensitive radiation detectors which will energize clearly audible alarm signals if accidental criticality...

10 CFR 70.24 - Criticality accident requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Criticality accident requirements. 70.24 Section 70.24... Applications § 70.24 Criticality accident requirements. (a) Each licensee authorized to possess special nuclear...-sensitive radiation detectors which will energize clearly audible alarm signals if accidental criticality...

10 CFR 70.24 - Criticality accident requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Criticality accident requirements. 70.24 Section 70.24... Applications § 70.24 Criticality accident requirements. (a) Each licensee authorized to possess special nuclear...-sensitive radiation detectors which will energize clearly audible alarm signals if accidental criticality...

10 CFR 70.24 - Criticality accident requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Criticality accident requirements. 70.24 Section 70.24... Applications § 70.24 Criticality accident requirements. (a) Each licensee authorized to possess special nuclear...-sensitive radiation detectors which will energize clearly audible alarm signals if accidental criticality...

On Critical Behaviour in Systems of Hamiltonian Partial Differential Equations.

PubMed

Dubrovin, Boris; Grava, Tamara; Klein, Christian; Moro, Antonio

2015-01-01

We study the critical behaviour of solutions to weakly dispersive Hamiltonian systems considered as perturbations of elliptic and hyperbolic systems of hydrodynamic type with two components. We argue that near the critical point of gradient catastrophe of the dispersionless system, the solutions to a suitable initial value problem for the perturbed equations are approximately described by particular solutions to the Painlevé-I (P[Formula: see text]) equation or its fourth-order analogue P[Formula: see text]. As concrete examples, we discuss nonlinear Schrödinger equations in the semiclassical limit. A numerical study of these cases provides strong evidence in support of the conjecture.

Specialized computer system to diagnose critical lined equipment

NASA Astrophysics Data System (ADS)

Yemelyanov, V. A.; Yemelyanova, N. Y.; Morozova, O. A.; Nedelkin, A. A.

2018-05-01

The paper presents data on the problem of diagnosing the lining condition at the iron and steel works. The authors propose and describe the structure of the specialized computer system to diagnose critical lined equipment. The relative results of diagnosing lining condition by the basic system and the proposed specialized computer system are presented. To automate evaluation of lining condition and support in making decisions regarding the operation mode of the lined equipment, the specialized software has been developed.

Neonatal and pediatric regionalized systems in pediatric emergency mass critical care

PubMed Central

Barfield, Wanda D.; Krug, Steven E.; Kanter, Robert K.; Gausche-Hill, Marianne; Brantley, Mary D.; Chung, Sarita; Kissoon, Niranjan

2015-01-01

Introduction Improved health outcomes are associated with neonatal and pediatric critical care in well-organized, cohesive, regionalized systems that are prepared to support and rehabilitate critically ill victims of a mass casualty event. However, present systems lack adequate surge capacity for neonatal and pediatric mass critical care. In this document, we outline the present reality and suggest alternative approaches. Methods In May 2008, the Task Force for Mass Critical Care published guidance on provision of mass critical care to adults. Acknowledging that the critical care needs of children during disasters were unaddressed by this effort, a 17-member Steering Committee, assembled by the Oak Ridge Institute for Science and Education with guidance from members of the American Academy of Pediatrics, convened in April 2009 to determine priority topic areas for pediatric emergency mass critical care recommendations. Steering Committee members established subcommittees by topic area and performed literature reviews of MEDLINE and Ovid databases. The Steering Committee produced draft outlines through consensus-based study of the literature and convened October 6–7, 2009, in New York, NY, to review and revise each outline. Eight draft documents were subsequently developed from the revised outlines as well as through searches of MEDLINE updated through March 2010. The Pediatric Emergency Mass Critical Care Task Force, composed of 36 experts from diverse public health, medical, and disaster response fields, convened in Atlanta, GA, on March 29–30, 2010. Feedback on each manuscript was compiled and the Steering Committee revised each document to reflect expert input in addition to the most current medical literature. Task Force Recommendations States and regions (facilitated by federal partners) should review current emergency operations and devise appropriate plans to address the population-based needs of infants and children in large-scale disasters. Action at

Indicator system for advanced nuclear plant control complex

DOEpatents

Scarola, Kenneth; Jamison, David S.; Manazir, Richard M.; Rescorl, Robert L.; Harmon, Daryl L.

1993-01-01

An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually. The integrated process status board (24) is at the apex of an information hierarchy that extends through four levels and provides access at each panel to the full display hierarchy. The control room panels are preferably of a modular construction, permitting the definition of inputs and outputs, the man machine interface, and the plant specific algorithms, to proceed in parallel with the fabrication of the panels, the installation of the equipment and the generic testing thereof.

Reactor Testing and Qualification: Prioritized High-level Criticality Testing Needs

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

S. Bragg-Sitton; J. Bess; J. Werner

2011-09-01

Researchers at the Idaho National Laboratory (INL) were tasked with reviewing possible criticality testing needs to support development of the fission surface power system reactor design. Reactor physics testing can provide significant information to aid in development of technologies associated with small, fast spectrum reactors that could be applied for non-terrestrial power systems, leading to eventual system qualification. Several studies have been conducted in recent years to assess the data and analyses required to design and build a space fission power system with high confidence that the system will perform as designed [Marcille, 2004a, 2004b; Weaver, 2007; Parry et al.,more » 2008]. This report will provide a summary of previous critical tests and physics measurements that are potentially applicable to the current reactor design (both those that have been benchmarked and those not yet benchmarked), summarize recent studies of potential nuclear testing needs for space reactor development and their applicability to the current baseline fission surface power (FSP) system design, and provide an overview of a suite of tests (separate effects, sub-critical or critical) that could fill in the information database to improve the accuracy of physics modeling efforts as the FSP design is refined. Some recommendations for tasks that could be completed in the near term are also included. Specific recommendations on critical test configurations will be reserved until after the sensitivity analyses being conducted by Los Alamos National Laboratory (LANL) are completed (due August 2011).« less

Renovated Korean nuclear safety and security system: A review and suggestions to successful settlement

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

Chung, W. S.; Yun, S. W.; Lee, D. S.

2012-07-01

Questions of whether past nuclear regulatory body of Korea is not a proper system to monitor and check the country's nuclear energy policy and utilization have been raised. Moreover, a feeling of insecurity regarding nuclear safety after the nuclear accident in Japan has spread across the public. This has stimulated a renovation of the nuclear safety regime in Korea. The Nuclear Safety and Security Commission (NSSC) was launched on October 26, 2011 as a regulatory body directly under the President in charge of strengthening independence and nuclear safety. This was a meaningful event as the NSSC it is a muchmore » more independent regulatory system for Korea. However, the NSSC itself does not guarantee an enhanced public acceptance of the nuclear policy and stable use nuclear energy. This study introduces the new NSSC system and its details in terms of organization structure, appropriateness of specialty, budget stability, and management system. (authors)« less

Safety system augmentation at Russian nuclear power plants

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

Scerbo, J.A.; Satpute, S.N.; Donkin, J.Y.

1996-12-31

This paper describes the design and procurement of a Class IE DC power supply system to upgrade plant safety at the Kola Nuclear Power Plant (NPP). Kola NPP is located above the Arctic circle at Polyarnie Zorie, Murmansk, Russia. Kola NPP consists of four units. Units 1 and 2 have VVER-440/230 type reactors: Units 3 and 4 have VVER-440/213 type reactors. The VVER-440 reactor design is similar to the pressurized water reactor design used in the US. This project provided redundant, Class 1E DC station batteries and DC switchboards for Kola NPP, Units 1 and 2. The new DC powermore » supply system was designed and procured in compliance with current nuclear design practices and requirements. Technical issues that needed to be addressed included reconciling the requirements in both US and Russian codes and satisfying the requirements of the Russian nuclear regulatory authority. Close interface with ATOMENERGOPROEKT (AEP), the Russian design organization, KOLA NPP plant personnel, and GOSATOMNADZOR (GAN), the Russian version of US Nuclear Regulatory Commission, was necessary to develop a design that would assure compliance with current Russian design requirements. Hence, this project was expected to serve as an example for plant upgrades at other similar VVER-440 nuclear plants. In addition to technical issues, the project needed to address language barriers and the logistics of shipping equipment to a remote section of the Former Soviet Union (FSU). This project was executed by Burns and Roe under the sponsorship of the US DOE as part of the International Safety Program (INSP). The INSP is a comprehensive effort, in cooperation with partners in other countries, to improve nuclear safety worldwide. A major element within the INSP is the improvement of the safety of Soviet-designed nuclear reactors.« less

Criticality in conserved dynamical systems: experimental observation vs. exact properties.

PubMed

Marković, Dimitrije; Gros, Claudius; Schuelein, André

2013-03-01

Conserved dynamical systems are generally considered to be critical. We study a class of critical routing models, equivalent to random maps, which can be solved rigorously in the thermodynamic limit. The information flow is conserved for these routing models and governed by cyclic attractors. We consider two classes of information flow, Markovian routing without memory and vertex routing involving a one-step routing memory. Investigating the respective cycle length distributions for complete graphs, we find log corrections to power-law scaling for the mean cycle length, as a function of the number of vertices, and a sub-polynomial growth for the overall number of cycles. When observing experimentally a real-world dynamical system one normally samples stochastically its phase space. The number and the length of the attractors are then weighted by the size of their respective basins of attraction. This situation is equivalent, for theory studies, to "on the fly" generation of the dynamical transition probabilities. For the case of vertex routing models, we find in this case power law scaling for the weighted average length of attractors, for both conserved routing models. These results show that the critical dynamical systems are generically not scale-invariant but may show power-law scaling when sampled stochastically. It is hence important to distinguish between intrinsic properties of a critical dynamical system and its behavior that one would observe when randomly probing its phase space.

Complex systems analysis of series of blackouts: cascading failure, critical points, and self-organization.

PubMed

Dobson, Ian; Carreras, Benjamin A; Lynch, Vickie E; Newman, David E

2007-06-01

We give an overview of a complex systems approach to large blackouts of electric power transmission systems caused by cascading failure. Instead of looking at the details of particular blackouts, we study the statistics and dynamics of series of blackouts with approximate global models. Blackout data from several countries suggest that the frequency of large blackouts is governed by a power law. The power law makes the risk of large blackouts consequential and is consistent with the power system being a complex system designed and operated near a critical point. Power system overall loading or stress relative to operating limits is a key factor affecting the risk of cascading failure. Power system blackout models and abstract models of cascading failure show critical points with power law behavior as load is increased. To explain why the power system is operated near these critical points and inspired by concepts from self-organized criticality, we suggest that power system operating margins evolve slowly to near a critical point and confirm this idea using a power system model. The slow evolution of the power system is driven by a steady increase in electric loading, economic pressures to maximize the use of the grid, and the engineering responses to blackouts that upgrade the system. Mitigation of blackout risk should account for dynamical effects in complex self-organized critical systems. For example, some methods of suppressing small blackouts could ultimately increase the risk of large blackouts.

2011 Annual Criticality Safety Program Performance Summary

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

Andrea Hoffman

The 2011 review of the INL Criticality Safety Program has determined that the program is robust and effective. The review was prepared for, and fulfills Contract Data Requirements List (CDRL) item H.20, 'Annual Criticality Safety Program performance summary that includes the status of assessments, issues, corrective actions, infractions, requirements management, training, and programmatic support.' This performance summary addresses the status of these important elements of the INL Criticality Safety Program. Assessments - Assessments in 2011 were planned and scheduled. The scheduled assessments included a Criticality Safety Program Effectiveness Review, Criticality Control Area Inspections, a Protection of Controlled Unclassified Information Inspection,more » an Assessment of Criticality Safety SQA, and this management assessment of the Criticality Safety Program. All of the assessments were completed with the exception of the 'Effectiveness Review' for SSPSF, which was delayed due to emerging work. Although minor issues were identified in the assessments, no issues or combination of issues indicated that the INL Criticality Safety Program was ineffective. The identification of issues demonstrates the importance of an assessment program to the overall health and effectiveness of the INL Criticality Safety Program. Issues and Corrective Actions - There are relatively few criticality safety related issues in the Laboratory ICAMS system. Most were identified by Criticality Safety Program assessments. No issues indicate ineffectiveness in the INL Criticality Safety Program. All of the issues are being worked and there are no imminent criticality concerns. Infractions - There was one criticality safety related violation in 2011. On January 18, 2011, it was discovered that a fuel plate bundle in the Nuclear Materials Inspection and Storage (NMIS) facility exceeded the fissionable mass limit, resulting in a technical safety requirement (TSR) violation. The TSR limits

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2009-11-23

there are no plans to do so.’”5 Critics expressed concern about the implications of these policies for testing and new weapons. A statement by...opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”6 Another critic felt that increased...cannot diagnose or remedy a problem in a warhead critical the U.S. nuclear deterrent without conducting a nuclear test.10 Similarly, a Statement of

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2010-01-06

the future, but there are no plans to do so.’”5 Critics expressed concern about the implications of these policies for testing and new weapons. A...seek the opportunity to design and build new nuclear weapons, and abandon a ten-year-old moratorium on nuclear weapons testing.”6 Another critic felt...warhead critical the U.S. nuclear deterrent without conducting a nuclear test.10 Similarly, a Statement of Administration Policy on S. 1547, FY2008

The NJOY Nuclear Data Processing System, Version 2016

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

Macfarlane, Robert; Muir, Douglas W.; Boicourt, R. M.

The NJOY Nuclear Data Processing System, version 2016, is a comprehensive computer code package for producing pointwise and multigroup cross sections and related quantities from evaluated nuclear data in the ENDF-4 through ENDF-6 legacy card-image formats. NJOY works with evaluated files for incident neutrons, photons, and charged particles, producing libraries for a wide variety of particle transport and reactor analysis codes.

Nuclear systems for space power and propulsion

NASA Technical Reports Server (NTRS)

Klein, M.

1971-01-01

As exploration and utilization of space proceeds through the 1970s, 1980s, and beyond, spacecraft in earth orbit will become increasingly larger, spacecraft will travel deeper into space, and space activities will involve more complex operations. These trends require increasing amounts of energy for power and propulsion. The role to be played by nuclear energy is presented, including plans for deep space missions using radioisotope generators, the reactor power systems for earth orbiting stations and satellites, and the role of nuclear propulsion in space transportation.

Passive cooling system for nuclear reactor containment structure

DOEpatents

Gou, Perng-Fei; Wade, Gentry E.

1989-01-01

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

'Known Secure Sensor Measurements' for Critical Infrastructure Systems: Detecting Falsification of System State

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

Miles McQueen; Annarita Giani

2011-09-01

This paper describes a first investigation on a low cost and low false alarm, reliable mechanism for detecting manipulation of critical physical processes and falsification of system state. We call this novel mechanism Known Secure Sensor Measurements (KSSM). The method moves beyond analysis of network traffic and host based state information, in fact it uses physical measurements of the process being controlled to detect falsification of state. KSSM is intended to be incorporated into the design of new, resilient, cost effective critical infrastructure control systems. It can also be included in incremental upgrades of already in- stalled systems for enhancedmore » resilience. KSSM is based on known secure physical measurements for assessing the likelihood of an attack and will demonstrate a practical approach to creating, transmitting, and using the known secure measurements for detection.« less

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.

Scanning nuclear resonance imaging of a hyperfine-coupled quantum Hall system.

PubMed

Hashimoto, Katsushi; Tomimatsu, Toru; Sato, Ken; Hirayama, Yoshiro

2018-06-07

Nuclear resonance (NR) is widely used to detect and characterise nuclear spin polarisation and conduction electron spin polarisation coupled by a hyperfine interaction. While the macroscopic aspects of such hyperfine-coupled systems have been addressed in most relevant studies, the essential role of local variation in both types of spin polarisation has been indicated in 2D semiconductor systems. In this study, we apply a recently developed local and highly sensitive NR based on a scanning probe to a hyperfine-coupled quantum Hall (QH) system in a 2D electron gas subject to a strong magnetic field. We succeed in imaging the NR intensity and Knight shift, uncovering the spatial distribution of both the nuclear and electron spin polarisation. The results reveal the microscopic origin of the nonequilibrium QH phenomena, and highlight the potential use of our technique in microscopic studies on various electron spin systems as well as their correlations with nuclear spins.

Nuclear reactor cavity floor passive heat removal system

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

Edwards, Tyler A.; Neeley, Gary W.; Inman, James B.

A nuclear reactor includes a reactor core disposed in a reactor pressure vessel. A radiological containment contains the nuclear reactor and includes a concrete floor located underneath the nuclear reactor. An ex vessel corium retention system includes flow channels embedded in the concrete floor located underneath the nuclear reactor, an inlet in fluid communication with first ends of the flow channels, and an outlet in fluid communication with second ends of the flow channels. In some embodiments the inlet is in fluid communication with the interior of the radiological containment at a first elevation and the outlet is in fluidmore » communication with the interior of the radiological containment at a second elevation higher than the first elevation. The radiological containment may include a reactor cavity containing a lower portion of the pressure vessel, wherein the concrete floor located underneath the nuclear reactor is the reactor cavity floor.« less

Coagulation and complement system in critically ill patients.

PubMed

Helling, H; Stephan, B; Pindur, G

2015-01-01

Activation of coagulation and inflammatory response including the complement system play a major role in the pathogenesis of critical illness. However, only limited data are available addressing the relationship of both pathways and its assessment of a predictive value for the clinical outcome in intense care medicine. Therefore, parameters of the coagulation and complement system were studied in patients with septicaemia and multiple trauma regarded as being exemplary for critical illness. 34 patients (mean age: 51.38 years (±16.57), 15 females, 19 males) were investigated at day 1 of admittance to the intensive care unit (ICU). Leukocytes, complement factors C3a and C5a were significantly (p <  0.0500) higher in sepsis than in trauma, whereas platelet count and plasma fibrinogen were significantly lower in multiple trauma. Activation markers of coagulation were elevated in both groups, however, thrombin-antithrombin-complex was significantly higher in multiple trauma. DIC scores of 5 were not exceeded in any of the two groups. Analysing the influences on mortality (11/34; 32.35% ), which was not different in both groups, non-survivors were significantly older, had significantly higher multiple organ failure (MOF) scores, lactate, abnormal prothrombin times and lower C1-inhibitor activities, even more pronounced in early deaths, than survivors. In septic non-survivors protein C was significantly lower than in trauma. We conclude from these data that activation of the complement system as part of the inflammatory response is a significant mechanism in septicaemia, whereas loss and consumption of blood components including parts of the coagulation and complement system is more characteristic for multiple trauma. Protein C in case of severe reduction might be of special concern for surviving in sepsis. Activation of haemostasis was occurring in both diseases, however, overt DIC was not confirmed in this study to be a leading mechanism in critically ill patients

Critical Infrastructure Protection- Los Alamos National Laboratory

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

Bofman, Ryan K.

Los Alamos National Laboratory (LANL) has been a key facet of Critical National Infrastructure since the nuclear bombing of Hiroshima exposed the nature of the Laboratory’s work in 1945. Common knowledge of the nature of sensitive information contained here presents a necessity to protect this critical infrastructure as a matter of national security. This protection occurs in multiple forms beginning with physical security, followed by cybersecurity, safeguarding of classified information, and concluded by the missions of the National Nuclear Security Administration.

A computer-aided diagnosis system of nuclear cataract.

PubMed

Li, Huiqi; Lim, Joo Hwee; Liu, Jiang; Mitchell, Paul; Tan, Ava Grace; Wang, Jie Jin; Wong, Tien Yin

2010-07-01

Cataracts are the leading cause of blindness worldwide, and nuclear cataract is the most common form of cataract. An algorithm for automatic diagnosis of nuclear cataract is investigated in this paper. Nuclear cataract is graded according to the severity of opacity using slit lamp lens images. Anatomical structure in the lens image is detected using a modified active shape model. On the basis of the anatomical landmark, local features are extracted according to clinical grading protocol. Support vector machine regression is employed for grade prediction. This is the first time that the nucleus region can be detected automatically in slit lamp images. The system is validated using clinical images and clinical ground truth on >5000 images. The success rate of structure detection is 95% and the average grading difference is 0.36 on a 5.0 scale. The automatic diagnosis system can improve the grading objectivity and potentially be used in clinics and population studies to save the workload of ophthalmologists.

Overview of Risk Mitigation for Safety-Critical Computer-Based Systems

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo

2015-01-01

This report presents a high-level overview of a general strategy to mitigate the risks from threats to safety-critical computer-based systems. In this context, a safety threat is a process or phenomenon that can cause operational safety hazards in the form of computational system failures. This report is intended to provide insight into the safety-risk mitigation problem and the characteristics of potential solutions. The limitations of the general risk mitigation strategy are discussed and some options to overcome these limitations are provided. This work is part of an ongoing effort to enable well-founded assurance of safety-related properties of complex safety-critical computer-based aircraft systems by developing an effective capability to model and reason about the safety implications of system requirements and design.

[Initial medical management in radiological accidents and nuclear disaster].

PubMed

Tanigawa, Koichi

2012-03-01

Major radiological emergencies include criticality in nuclear power plants or terrorist attacks using dirty bombs or nuclear device detonation. Because irradiation itself does not cause any immediate death of the victims, and there is a minimum risk of secondary irradiation to medical personnel during decontamination procedures, lifesaving treatments should be prioritized. When a major radiological accident occurs, information is scarce and/or becomes intricate. We might face with significant difficulties in determining the exact culprits of the event, i.e., radiological or chemical or others. Therefore, it is strongly recommended for the national and local governments, related organizations and hospitals to develop comprehensive systems to cope with all hazards(chemical, biological, radiation, nuclear, and explosion) under the common incident command system.

A novel pulse height analysis technique for nuclear spectroscopic and imaging systems

NASA Astrophysics Data System (ADS)

Tseng, H. H.; Wang, C. Y.; Chou, H. P.

2005-08-01

The proposed pulse height analysis technique is based on the constant and linear relationship between pulse width and pulse height generated from front-end electronics of nuclear spectroscopic and imaging systems. The present technique has successfully implemented into the sump water radiation monitoring system in a nuclear power plant. The radiation monitoring system uses a NaI(Tl) scintillator to detect radioactive nuclides of Radon daughters brought down by rain. The technique is also used for a nuclear medical imaging system. The system uses a position sensitive photomultiplier tube coupled with a scintillator. The proposed techniques has greatly simplified the electronic design and made the system a feasible one for potable applications.

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).

Critical phenomena in the general spherically symmetric Einstein-Yang-Mills system

NASA Astrophysics Data System (ADS)

Maliborski, Maciej; Rinne, Oliver

2018-02-01

We study critical behavior in gravitational collapse of a general spherically symmetric Yang-Mills field coupled to the Einstein equations. Unlike the magnetic ansatz used in previous numerical work, the general Yang-Mills connection has two degrees of freedom in spherical symmetry. This fact changes the phenomenology of critical collapse dramatically. The magnetic sector features both type I and type II critical collapse, with universal critical solutions. In contrast, in the general system type I disappears and the critical behavior at the threshold between dispersal and black hole formation is always type II. We obtain values of the mass scaling and echoing exponents close to those observed in the magnetic sector, however we find some indications that the critical solution differs from the purely magnetic discretely self-similar attractor and exact self-similarity and universality might be lost. The additional "type III" critical phenomenon in the magnetic sector, where black holes form on both sides of the threshold but the Yang-Mills potential is in different vacuum states and there is a mass gap, also disappears in the general system. We support our dynamical numerical simulations with calculations in linear perturbation theory; for instance, we compute quasi-normal modes of the unstable attractor (the Bartnik-McKinnon soliton) in type I collapse in the magnetic sector.

Nuclear Technology Series. Course 5: Introduction to Nuclear Systems.

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…

Nuclear Technology Series. Course 24: Nuclear Systems and Safety.

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…

Space nuclear power: Key to outer solar system exploration

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

Bennett, G.L.; Allen, D.M.

1998-07-01

In 1995, in response to threatened budget cuts, the American Institute of Aeronautics and Astronautics (AIAA) approved a position paper supporting the maintenance of the technology base for space nuclear power. The position paper contained four recomemndations: (1) DOE, NASA, and DoD should develop and support an integrated program that maintains the nuclear option and develops the needed high-payoff technologies; (2) Congress should provide strong, continuing financial and political support for the agencies' program; (3) Government and industry leaders should voice their advocacy for a strong space nuclear power program to support future system requirements; and (4) The US shouldmore » continue to maintain its cooperation and technical interchanges with other countries to advance nuclear power source technology and to promote nuclear safety.« less

Photonuclear-based, nuclear material detection system for cargo containers

NASA Astrophysics Data System (ADS)

Jones, J. L.; Yoon, W. Y.; Norman, D. R.; Haskell, K. J.; Zabriskie, J. M.; Watson, S. M.; Sterbentz, J. W.

2005-12-01

The Idaho National Laboratory (INL) has been developing electron accelerator-based, photonuclear inspection technologies for over a decade. A current need, having important national implications, has been with the detection of smuggled nuclear material within air- and, especially, sea-cargo transportation containers. This paper describes the latest pulsed, photonuclear inspection system for nuclear material detection and identification in cargo configurations, the numerical responses of 5 kg of a nuclear material placed within selected cargo configurations, and the technology's potential role in addressing future inspection needs.

Long-Term Planning for Nuclear Energy Systems Under Deep Uncertainty

NASA Astrophysics Data System (ADS)

Kim, Lance Kyungwoo

Long-term planning for nuclear energy systems has been an area of interest for policy planners and systems designers to assess and manage the complexity of the system and the long-term, wide-ranging societal impacts of decisions. However, traditional planning tools are often poorly equipped to cope with the deep parametric, structural, and value uncertainties in long-term planning. A more robust, multiobjective decision-making method is applied to a model of the nuclear fuel cycle to address the many sources of complexity, uncertainty, and ambiguity inherent to long-term planning. Unlike prior studies that rely on assessing the outcomes of a limited set of deployment strategies, solutions in this study arise from optimizing behavior against multiple incommensurable objectives, utilizing goal-seeking multiobjective evolutionary algorithms to identify minimax regret solutions across various demand scenarios. By excluding inferior and infeasible solutions, the choice between the Pareto optimal solutions depends on a decision-maker's preferences for the defined outcomes---limiting analyst bias and increasing transparency. Though simplified by the necessity of reducing computational burdens, the nuclear fuel cycle model captures important phenomena governing the behavior of the nuclear energy system relevant to the decision to close the fuel cycle---incorporating reactor population dynamics, material stocks and flows, constraints on material flows, and outcomes of interest to decision-makers. Technology neutral performance criteria are defined consistent with the Generation IV International Forum goals of improved security and proliferation resistance based on structural features of the nuclear fuel cycle, natural resource sustainability, and waste production. A review of safety risks and the economic history of the development of nuclear technology suggests that safety and economic criteria may not be decisive criteria as the safety risks posed by alternative fuel

TOPAZ II Anti-Criticality Device Rapid Prototype

NASA Astrophysics Data System (ADS)

Campbell, Donald R.; Otting, William D.

1994-07-01

The Ballistic Missile Defense Organization (BMDO) has been working on a Nuclear Electric Propulsion Space Test Project (NEPSTP) using an existing Russian Topaz II reactor system to power the NEPSTP satellite. Safety investigations have shown that it will be possible to safely launch the Topaz II system in the United States with some modification to preclude water flooded criticality. A ``fuel-out'' water subcriticality concept was selected by the Los Alamos National Laboratory (LANL) as the baseline concept. A fuel-out anti-criticality device (ACD) conceptual design was developed by Rockwell. The concept functions to hold the fuel from the four centermost thermionic fuel elements (TFEs) outside the reactor during launch and reliably inserts the fuel into the reactor once the operational orbit is achieved. A four-tenths scale ACD rapid prototype model, fabricated from the CATIA solids design model, clearly shows in three dimensions the relative size and spatial relationship of the ACD components.

Critical quench dynamics in confined systems.

PubMed

Collura, Mario; Karevski, Dragi

2010-05-21

We analyze the coherent quantum evolution of a many-particle system after slowly sweeping a power-law confining potential. The amplitude of the confining potential is varied in time along a power-law ramp such that the many-particle system finally reaches or crosses a critical point. Under this protocol we derive general scaling laws for the density of excitations created during the nonadiabatic sweep of the confining potential. It is found that the mean excitation density follows an algebraic law as a function of the sweeping rate with an exponent that depends on the space-time properties of the potential. We confirm our scaling laws by first order adiabatic calculation and exact results on the Ising quantum chain with a varying transverse field.

Characteristics of Hydrogen Monitoring Systems for Severe Accident Management at a Nuclear Power Plant

NASA Astrophysics Data System (ADS)

Petrosyan, V. G.; Yeghoyan, E. A.; Grigoryan, A. D.; Petrosyan, A. P.; Movsisyan, M. R.

2018-02-01

One of the main objectives of severe accident management at a nuclear power plant is to protect the integrity of the containment, for which the most serious threat is possible ignition of the generated hydrogen. There should be a monitoring system providing information support of NPP personnel, ensuring data on the current state of a containment gaseous environment and trends in its composition changes. Monitoring systems' requisite characteristics definition issues are considered by the example of a particular power unit. Major characteristics important for proper information support are discussed. Some features of progression of severe accident scenarios at considered power unit are described and a possible influence of the hydrogen concentration monitoring system performance on the information support reliability in a severe accident is analyzed. The analysis results show that the following technical characteristics of the combustible gas monitoring systems are important for the proper information support of NPP personnel in the event of a severe accident at a nuclear power plant: measured parameters, measuring ranges and errors, update rate, minimum detectable concentration of combustible gas, monitoring reference points, environmental qualification parameters of the system components. For NPP power units with WWER-440/270 (230) type reactors, which have a relatively small containment volume, the update period for measurement results is a critical characteristic of the containment combustible gas monitoring system, and the choice of monitoring reference points should be focused not so much on the definition of places of possible hydrogen pockets but rather on the definition of places of a possible combustible mixture formation. It may be necessary for the above-mentioned power units to include in the emergency operating procedures measures aimed at a timely heat removal reduction from the containment environment if there are signs of a severe accident phase

Nuclear targeting of viral and non-viral DNA.

PubMed

Chowdhury, E H

2009-07-01

The nuclear envelope presents a major barrier to transgene delivery and expression using a non-viral vector. Virus is capable of overcoming the barrier to deliver their genetic materials efficiently into the nucleus by virtue of the specialized protein components with the unique amino acid sequences recognizing cellular nuclear transport machinery. However, considering the safety issues in the clinical gene therapy for treating critical human diseases, non-viral systems are highly promising compared with their viral counterparts. This review summarizes the progress on exploring the nuclear traffic mechanisms for the prominent viral vectors and the technological innovations for the nuclear delivery of non-viral DNA by mimicking those natural processes evolved for the viruses as well as for many cellular proteins.

Criticality Safety Basics for INL FMHs and CSOs

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

V. L. Putman

2012-04-01

Nuclear power is a valuable and efficient energy alternative in our energy-intensive society. However, material that can generate nuclear power has properties that require this material be handled with caution. If improperly handled, a criticality accident could result, which could severely harm workers. This document is a modular self-study guide about Criticality Safety Principles. This guide's purpose it to help you work safely in areas where fissionable nuclear materials may be present, avoiding the severe radiological and programmatic impacts of a criticality accident. It is designed to stress the fundamental physical concepts behind criticality controls and the importance of criticalitymore » safety when handling fissionable materials outside nuclear reactors. This study guide was developed for fissionable-material-handler and criticality-safety-officer candidates to use with related web-based course 00INL189, BEA Criticality Safety Principles, and to help prepare for the course exams. These individuals must understand basic information presented here. This guide may also be useful to other Idaho National Laboratory personnel who must know criticality safety basics to perform their assignments safely or to design critically safe equipment or operations. This guide also includes additional information that will not be included in 00INL189 tests. The additional information is in appendices and paragraphs with headings that begin with 'Did you know,' or with, 'Been there Done that'. Fissionable-material-handler and criticality-safety-officer candidates may review additional information at their own discretion. This guide is revised as needed to reflect program changes, user requests, and better information. Issued in 2006, Revision 0 established the basic text and integrated various programs from former contractors. Revision 1 incorporates operation and program changes implemented since 2006. It also incorporates suggestions, clarifications, and additional

Integrated Response Time Evaluation Methodology for the Nuclear Safety Instrumentation System

NASA Astrophysics Data System (ADS)

Lee, Chang Jae; Yun, Jae Hee

2017-06-01

Safety analysis for a nuclear power plant establishes not only an analytical limit (AL) in terms of a measured or calculated variable but also an analytical response time (ART) required to complete protective action after the AL is reached. If the two constraints are met, the safety limit selected to maintain the integrity of physical barriers used for preventing uncontrolled radioactivity release will not be exceeded during anticipated operational occurrences and postulated accidents. Setpoint determination methodologies have actively been developed to ensure that the protective action is initiated before the process conditions reach the AL. However, regarding the ART for a nuclear safety instrumentation system, an integrated evaluation methodology considering the whole design process has not been systematically studied. In order to assure the safety of nuclear power plants, this paper proposes a systematic and integrated response time evaluation methodology that covers safety analyses, system designs, response time analyses, and response time tests. This methodology is applied to safety instrumentation systems for the advanced power reactor 1400 and the optimized power reactor 1000 nuclear power plants in South Korea. The quantitative evaluation results are provided herein. The evaluation results using the proposed methodology demonstrate that the nuclear safety instrumentation systems fully satisfy corresponding requirements of the ART.

Concentration-dependent Effects of Nuclear Lamins on Nuclear Size in Xenopus and Mammalian Cells*

PubMed Central

Jevtić, Predrag; Edens, Lisa J.; Li, Xiaoyang; Nguyen, Thang; Chen, Pan; Levy, Daniel L.

2015-01-01

A fundamental question in cell biology concerns the regulation of organelle size. While nuclear size is exquisitely controlled in different cell types, inappropriate nuclear enlargement is used to diagnose and stage cancer. Clarifying the functional significance of nuclear size necessitates an understanding of the mechanisms and proteins that control nuclear size. One structural component implicated in the regulation of nuclear morphology is the nuclear lamina, a meshwork of intermediate lamin filaments that lines the inner nuclear membrane. However, there has not been a systematic investigation of how the level and type of lamin expression influences nuclear size, in part due to difficulties in precisely controlling lamin expression levels in vivo. In this study, we circumvent this limitation by studying nuclei in Xenopus laevis egg and embryo extracts, open biochemical systems that allow for precise manipulation of lamin levels by the addition of recombinant proteins. We find that nuclear growth and size are sensitive to the levels of nuclear lamins, with low and high concentrations increasing and decreasing nuclear size, respectively. Interestingly, each type of lamin that we tested (lamins B1, B2, B3, and A) similarly affected nuclear size whether added alone or in combination, suggesting that total lamin concentration, and not lamin type, is more critical to determining nuclear size. Furthermore, we show that altering lamin levels in vivo, both in Xenopus embryos and mammalian tissue culture cells, also impacts nuclear size. These results have implications for normal development and carcinogenesis where both nuclear size and lamin expression levels change. PMID:26429910

Quantum critical dynamics of the boson system in the Ginzburg-Landau model

NASA Astrophysics Data System (ADS)

Vasin, M. G.

2014-12-01

The quantum critical dynamics of the quantum phase transitions is considered. In the framework of the unified theory, based on the Keldysh technique, we consider the crossover from the classical to the quantum description of the boson many-body system dynamics close to the second order quantum phase transition. It is shown that in this case the upper critical space dimension of this model is dc+=2, therefore the quantum critical dynamics approach is useful in case of d<2. In the one-dimension system the phase coherence time does diverge at the quantum critical point, gc, and has the form of τ∝-ln∣g-gc∣/∣g-gc∣, the correlation radius diverges as rc∝∣g-gc∣(ν=0.6).

Nuclear thermal propulsion test facility requirements and development strategy

NASA Technical Reports Server (NTRS)

Allen, George C.; Warren, John; Clark, J. S.

1991-01-01

The Nuclear Thermal Propulsion (NTP) subpanel of the Space Nuclear Propulsion Test Facilities Panel evaluated facility requirements and strategies for nuclear thermal propulsion systems development. High pressure, solid core concepts were considered as the baseline for the evaluation, with low pressure concepts an alternative. The work of the NTP subpanel revealed that a wealth of facilities already exists to support NTP development, and that only a few new facilities must be constructed. Some modifications to existing facilities will be required. Present funding emphasis should be on long-lead-time items for the major new ground test facility complex and on facilities supporting nuclear fuel development, hot hydrogen flow test facilities, and low power critical facilities.

System Theoretic Frameworks for Mitigating Risk Complexity in the Nuclear Fuel Cycle

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

Williams, Adam David; Mohagheghi, Amir H.; Cohn, Brian

In response to the expansion of nuclear fuel cycle (NFC) activities -- and the associated suite of risks -- around the world, this project evaluated systems-based solutions for managing such risk complexity in multimodal and multi-jurisdictional international spent nuclear fuel (SNF) transportation. By better understanding systemic risks in SNF transportation, developing SNF transportation risk assessment frameworks, and evaluating these systems-based risk assessment frameworks, this research illustrated interdependency between safety, security, and safeguards risks is inherent in NFC activities and can go unidentified when each "S" is independently evaluated. Two novel system-theoretic analysis techniques -- dynamic probabilistic risk assessment (DPRA) andmore » system-theoretic process analysis (STPA) -- provide integrated "3S" analysis to address these interdependencies and the research results suggest a need -- and provide a way -- to reprioritize United States engagement efforts to reduce global nuclear risks. Lastly, this research identifies areas where Sandia National Laboratories can spearhead technical advances to reduce global nuclear dangers.« less

Outsourcing critical financial system operations.

PubMed

Cox, Nora; Pilbauer, Jan

2018-01-01

Payments Canada provides Canada's national payments systems and is responsible for the clearing and settlement infrastructure, processes and rules that underpin the exchange of billions of dollars each day through the Canadian economy. Strategic sourcing is a reality for this small organisation with a broad scope of national regulations and global standards to comply with. This paper outlines Payments Canada's approach to outsourcing its critical financial system operations, which centres on four key principles: strong relationship management; continuous learning, recording and reporting; evaluating the business landscape; and a commitment to evolving the organisation to greater resilience. This last point is covered in detail with an exploration of the organisation's resilience and security strategy as well as its risk appetite. As Payments Canada progresses to its future state, which includes modernising its core payment systems, underlying rules and standards, risk management for the industry as a whole will remain at the forefront of its collective mind. The expectation is that outsourcing will remain a fundamental element of its operating model in future, a strategy that will ensure the organisation can focus on its core business competencies and eliminate the need to develop and support in-house expertise in commodity areas.

Small collision systems: Theory overview on cold nuclear matter effects

NASA Astrophysics Data System (ADS)

Armesto, Néstor

2018-02-01

Many observables measured at the Relativistic Heavy Ion Collider and the Large Hadron Collider show a smooth transition between proton-proton and protonnucleus collisions (small systems), and nucleus-nucleus collisions (large systems), when represented versus some variable like the multiplicity in the event. In this contribution I review some of the physics mechanisms, named cold nuclear matter effects, that may lead to a collective-like behaviour in small systems beyond the macroscopic description provided by relativistic hydrodynamics. I focus on the nuclear modification of parton densities, single inclusive particle production and correlations.

Nuclear electric propulsion mission engineering study. Volume 2: Final report

NASA Technical Reports Server (NTRS)

1973-01-01

Results of a mission engineering analysis of nuclear-thermionic electric propulsion spacecraft for unmanned interplanetary and geocentric missions are summarized. Critical technologies associated with the development of nuclear electric propulsion (NEP) are assessed, along with the impact of its availability on future space programs. Outer planet and comet rendezvous mission analysis, NEP stage design for geocentric and interplanetary missions, NEP system development cost and unit costs, and technology requirements for NEP stage development are studied.

Strategic defense initiative: critical issues

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

Nuckolls, J.H.

The objectives of the Strategic Defense Initiative (SDI) as outlined by President Reagan are discussed. The principal objective for SDI is as a defense against ballistic missiles. Soviet objections and a summary of US-USSR dialogue on the subject are reviewed. Most US studies have been critical of SDI. Four critical issues are addressed in depth: are defense weapons technologically feasible which have high economic leverage relative to offensive ballistic missiles; would the defense feasibility and leverage be degraded or enhanced in the technological race between weapons innovation and countermeasures; could stability be achieved during and after the transition to themore » defense dominated world envisioned by SDI proponents; would the deployment of high leverage defensive weapons increase or decrease the security of NATO Europe, and the probability of major conventional or nuclear wars. The issue of SDI may lead to a paradox that contains the seeds of catastrophe. The author concludes by warning that nuclear disarmament may eliminate the highly successful deterrent mechanism for avoiding another major world war. In a world made safe for major conventional wars by the apparent ''elimination'' of nuclear weapons, the leaders in a conventional World War III - involving unimaginable suffering, hatred, terror, and death - would be strongly motivated to introduce nuclear weapons in the crucial decisive battles. Even if diplomacy could ''eliminate'' nuclear weapons, man's knowledge of nuclear weapons can never be eliminated. The paradox is the attempt to eliminate nuclear weapons may maximize the probability of their use. (DMC)« less

Firm Size, a Self-Organized Critical Phenomenon: Evidence from the Dynamical Systems Theory

NASA Astrophysics Data System (ADS)

Chandra, Akhilesh

This research draws upon a recent innovation in the dynamical systems literature called the theory of self -organized criticality (SOC) (Bak, Tang, and Wiesenfeld 1988) to develop a computational model of a firm's size by relating its internal and the external sub-systems. As a holistic paradigm, the theory of SOC implies that a firm as a composite system of many degrees of freedom naturally evolves to a critical state in which a minor event starts a chain reaction that can affect either a part or the system as a whole. Thus, the global features of a firm cannot be understood by analyzing its individual parts separately. The causal framework builds upon a constant capital resource to support a volume of production at the existing level of efficiency. The critical size is defined as the production level at which the average product of a firm's factors of production attains its maximum value. The non -linearity is inferred by a change in the nature of relations at the border of criticality, between size and the two performance variables, viz., the operating efficiency and the financial efficiency. The effect of breaching the critical size is examined on the stock price reactions. Consistent with the theory of SOC, it is hypothesized that the temporal response of a firm breaching the level of critical size should behave as a flicker noise (1/f) process. The flicker noise is characterized by correlations extended over a wide range of time scales, indicating some sort of cooperative effect among a firm's degrees of freedom. It is further hypothesized that a firm's size evolves to a spatial structure with scale-invariant, self-similar (fractal) properties. The system is said to be self-organized inasmuch as it naturally evolves to the state of criticality without any detailed specifications of the initial conditions. In this respect, the critical state is an attractor of the firm's dynamics. Another set of hypotheses examines the relations between the size and the

Integration and Utilization of Nuclear Systems on the Moon and Mars

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

Houts, Michael G.; Schmidt, George R.; Bragg-Sitton, Shannon

2006-01-20

Over the past five decades numerous studies have identified nuclear energy as an enhancing or enabling technology for planetary surface exploration missions. This includes both radioisotope and fission sources for providing both heat and electricity. Nuclear energy sources were used to provide electricity on Apollo missions 12, 14, 15, 16, and 17, and on the Mars Viking landers. Very small nuclear energy sources were used to provide heat on the Mars Pathfinder, Spirit, and Opportunity rovers. Research has been performed at NASA MSFC to help assess potential issues associated with surface nuclear energy sources, and to generate data that couldmore » be useful to a future program. Research areas include System Integration, use of Regolith as Radiation Shielding, Waste Heat Rejection, Surface Environmental Effects on the Integrated System, Thermal Simulators, Surface System Integration / Interface / Interaction Testing, End-to-End Breadboard Development, Advanced Materials Development, Surface Energy Source Coolants, and Planetary Surface System Thermal Management and Control. This paper provides a status update on several of these research areas.« less

An Approach for Validating Actinide and Fission Product Burnup Credit Criticality Safety Analyses: Criticality (k eff) Predictions

DOE PAGES

Scaglione, John M.; Mueller, Don E.; Wagner, John C.

2014-12-01

One of the most important remaining challenges associated with expanded implementation of burnup credit in the United States is the validation of depletion and criticality calculations used in the safety evaluation—in particular, the availability and use of applicable measured data to support validation, especially for fission products (FPs). Applicants and regulatory reviewers have been constrained by both a scarcity of data and a lack of clear technical basis or approach for use of the data. In this study, this paper describes a validation approach for commercial spent nuclear fuel (SNF) criticality safety (k eff) evaluations based on best-available data andmore » methods and applies the approach for representative SNF storage and transport configurations/conditions to demonstrate its usage and applicability, as well as to provide reference bias results. The criticality validation approach utilizes not only available laboratory critical experiment (LCE) data from the International Handbook of Evaluated Criticality Safety Benchmark Experiments and the French Haut Taux de Combustion program to support validation of the principal actinides but also calculated sensitivities, nuclear data uncertainties, and limited available FP LCE data to predict and verify individual biases for relevant minor actinides and FPs. The results demonstrate that (a) sufficient critical experiment data exist to adequately validate k eff calculations via conventional validation approaches for the primary actinides, (b) sensitivity-based critical experiment selection is more appropriate for generating accurate application model bias and uncertainty, and (c) calculated sensitivities and nuclear data uncertainties can be used for generating conservative estimates of bias for minor actinides and FPs. Results based on the SCALE 6.1 and the ENDF/B-VII.0 cross-section libraries indicate that a conservative estimate of the bias for the minor actinides and FPs is 1.5% of their worth within the

A universal indicator of critical state transitions in noisy complex networked systems

PubMed Central

Liang, Junhao; Hu, Yanqing; Chen, Guanrong; Zhou, Tianshou

2017-01-01

Critical transition, a phenomenon that a system shifts suddenly from one state to another, occurs in many real-world complex networks. We propose an analytical framework for exactly predicting the critical transition in a complex networked system subjected to noise effects. Our prediction is based on the characteristic return time of a simple one-dimensional system derived from the original higher-dimensional system. This characteristic time, which can be easily calculated using network data, allows us to systematically separate the respective roles of dynamics, noise and topology of the underlying networked system. We find that the noise can either prevent or enhance critical transitions, playing a key role in compensating the network structural defect which suffers from either internal failures or environmental changes, or both. Our analysis of realistic or artificial examples reveals that the characteristic return time is an effective indicator for forecasting the sudden deterioration of complex networks. PMID:28230166

An integral nuclear power and propulsion system concept

NASA Astrophysics Data System (ADS)

Choong, Phillip T.; Teofilo, Vincent L.; Begg, Lester L.; Dunn, Charles; Otting, William

An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion. The integral system is capable of long-life power operation and multiple propulsion operations. At an optimal thrust level, the integral system can maintain the minimal delta-V requirement while minimizing the orbital transfer time. A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion. The resulting savings in orbital transfer time and the substantial reduction of overall lift requirement enables the use of low-cost launchers for several near-term military satellite missions.

Nuclear reactor pressure vessel support system

DOEpatents

Sepelak, George R.

1978-01-01

A support system for nuclear reactor pressure vessels which can withstand all possible combinations of stresses caused by a postulated core disrupting accident during reactor operation. The nuclear reactor pressure vessel is provided with a flange around the upper periphery thereof, and the flange includes an annular vertical extension formed integral therewith. A support ring is positioned atop of the support ledge and the flange vertical extension, and is bolted to both members. The plug riser is secured to the flange vertical extension and to the top of a radially outwardly extension of the rotatable plug. This system eliminates one joint through which fluids contained in the vessel could escape by making the fluid flow path through the joint between the flange and the support ring follow the same path through which fluid could escape through the plug risers. In this manner, the sealing means to prohibit the escape of contained fluids through the plug risers can also prohibit the escape of contained fluid through the securing joint.

Upgrades to the NESS (Nuclear Engine System Simulation) Code

NASA Technical Reports Server (NTRS)

Fittje, James E.

2007-01-01

In support of the President's Vision for Space Exploration, the Nuclear Thermal Rocket (NTR) concept is being evaluated as a potential propulsion technology for human expeditions to the moon and Mars. The need for exceptional propulsion system performance in these missions has been documented in numerous studies, and was the primary focus of a considerable effort undertaken during the 1960's and 1970's. The NASA Glenn Research Center is leveraging this past NTR investment in their vehicle concepts and mission analysis studies with the aid of the Nuclear Engine System Simulation (NESS) code. This paper presents the additional capabilities and upgrades made to this code in order to perform higher fidelity NTR propulsion system analysis and design.

Critical fermion density for restoring spontaneously broken symmetry

NASA Astrophysics Data System (ADS)

Kleinert, Hagen; Xue, She-Sheng

2015-07-01

We show how the phenomenon of spontaneous symmetry breakdown is affected by the presence of a sea of fermions in the system. When its density exceeds a critical value, the broken symmetry can be restored. We calculate the critical value and discuss the consequences for three different physical systems: First, for the Standard Model (SM) of particle physics, where the spontaneous symmetry breakdown leads to nonzero masses of intermediate gauge bosons and fermions. The symmetry restoration will greatly enhance various processes with dramatic consequences for the early universe. Second, for the Gell-Mann-Lévy σ-model of nuclear physics, where the symmetry breakdown gives rise to the nucleon and meson masses. The symmetry restoration may have important consequences for formation or collapse of stellar cores. Third, for the superconductive phase of condensed-matter, where the BCS condensate at low-temperature may be destroyed by a too large electron density.

Dynamic nuclear polarization methods in solids and solutions to explore membrane proteins and membrane systems.

PubMed

Cheng, Chi-Yuan; Han, Songi

2013-01-01

Membrane proteins regulate vital cellular processes, including signaling, ion transport, and vesicular trafficking. Obtaining experimental access to their structures, conformational fluctuations, orientations, locations, and hydration in membrane environments, as well as the lipid membrane properties, is critical to understanding their functions. Dynamic nuclear polarization (DNP) of frozen solids can dramatically boost the sensitivity of current solid-state nuclear magnetic resonance tools to enhance access to membrane protein structures in native membrane environments. Overhauser DNP in the solution state can map out the local and site-specific hydration dynamics landscape of membrane proteins and lipid membranes, critically complementing the structural and dynamics information obtained by electron paramagnetic resonance spectroscopy. Here, we provide an overview of how DNP methods in solids and solutions can significantly increase our understanding of membrane protein structures, dynamics, functions, and hydration in complex biological membrane environments.

ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

NASA Astrophysics Data System (ADS)

Kahler, A. C.; MacFarlane, R. E.; Mosteller, R. D.; Kiedrowski, B. C.; Frankle, S. C.; Chadwick, M. B.; McKnight, R. D.; Lell, R. M.; Palmiotti, G.; Hiruta, H.; Herman, M.; Arcilla, R.; Mughabghab, S. F.; Sublet, J. C.; Trkov, A.; Trumbull, T. H.; Dunn, M.

2011-12-01

The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., "ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data," Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2008-09-03

Spent nuclear fuel disposal has remained the most critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation...inalienable right and by and large, neither have U.S. government officials. However, the case of Iran raises perhaps the most critical question in...the enrichment process can take advantage of the slight difference in atomic mass between 235U and 238U. The typical enrichment process requires

Random-fractal Ansatz for the configurations of two-dimensional critical systems

NASA Astrophysics Data System (ADS)

Lee, Ching Hua; Ozaki, Dai; Matsueda, Hiroaki

2016-12-01

Critical systems have always intrigued physicists and precipitated the development of new techniques. Recently, there has been renewed interest in the information contained in the configurations of classical critical systems, whose computation do not require full knowledge of the wave function. Inspired by holographic duality, we investigated the entanglement properties of the classical configurations (snapshots) of the Potts model by introducing an Ansatz ensemble of random fractal images. By virtue of the central limit theorem, our Ansatz accurately reproduces the entanglement spectra of actual Potts snapshots without any fine tuning of parameters or artificial restrictions on ensemble choice. It provides a microscopic interpretation of the results of previous studies, which established a relation between the scaling behavior of snapshot entropy and the critical exponent. More importantly, it elucidates the role of ensemble disorder in restoring conformal invariance, an aspect previously ignored. Away from criticality, the breakdown of scale invariance leads to a renormalization of the parameter Σ in the random fractal Ansatz, whose variation can be used as an alternative determination of the critical exponent. We conclude by providing a recipe for the explicit construction of fractal unit cells consistent with a given scaling exponent.

Basic Research Needs for Advanced Nuclear Systems. Report of the Basic Energy Sciences Workshop on Basic Research Needs for Advanced Nuclear Energy Systems, July 31-August 3, 2006

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

Roberto, J.; Diaz de la Rubia, T.; Gibala, R.

2006-10-01

-ray sources, neutron sources, nanoscale science research centers, and supercomputers, offer the opportunity to transform and accelerate the fundamental materials and chemical sciences that underpin technology development for advanced nuclear energy systems. The fundamental challenge is to understand and control chemical and physical phenomena in multi-component systems from femto-seconds to millennia, at temperatures to 1000?C, and for radiation doses to hundreds of displacements per atom (dpa). This is a scientific challenge of enormous proportions, with broad implications in the materials science and chemistry of complex systems. New understanding is required for microstructural evolution and phase stability under relevant chemical and physical conditions, chemistry and structural evolution at interfaces, chemical behavior of actinide and fission-product solutions, and nuclear and thermomechanical phenomena in fuels and waste forms. First-principles approaches are needed to describe f-electron systems, design molecules for separations, and explain materials failure mechanisms. Nanoscale synthesis and characterization methods are needed to understand and design materials and interfaces with radiation, temperature, and corrosion resistance. Dynamical measurements are required to understand fundamental physical and chemical phenomena. New multiscale approaches are needed to integrate this knowledge into accurate models of relevant phenomena and complex systems across multiple length and time scales.« less

A reflective lens: applying critical systems thinking and visual methods to ecohealth research.

PubMed

Cleland, Deborah; Wyborn, Carina

2010-12-01

Critical systems methodology has been advocated as an effective and ethical way to engage with the uncertainty and conflicting values common to ecohealth problems. We use two contrasting case studies, coral reef management in the Philippines and national park management in Australia, to illustrate the value of critical systems approaches in exploring how people respond to environmental threats to their physical and spiritual well-being. In both cases, we used visual methods--participatory modeling and rich picturing, respectively. The critical systems methodology, with its emphasis on reflection, guided an appraisal of the research process. A discussion of these two case studies suggests that visual methods can be usefully applied within a critical systems framework to offer new insights into ecohealth issues across a diverse range of socio-political contexts. With this article, we hope to open up a conversation with other practitioners to expand the use of visual methods in integrated research.

Engine System Model Development for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Nelson, Karl W.; Simpson, Steven P.

2006-01-01

In order to design, analyze, and evaluate conceptual Nuclear Thermal Propulsion (NTP) engine systems, an improved NTP design and analysis tool has been developed. The NTP tool utilizes the Rocket Engine Transient Simulation (ROCETS) system tool and many of the routines from the Enabler reactor model found in Nuclear Engine System Simulation (NESS). Improved non-nuclear component models and an external shield model were added to the tool. With the addition of a nearly complete system reliability model, the tool will provide performance, sizing, and reliability data for NERVA-Derived NTP engine systems. A new detailed reactor model is also being developed and will replace Enabler. The new model will allow more flexibility in reactor geometry and include detailed thermal hydraulics and neutronics models. A description of the reactor, component, and reliability models is provided. Another key feature of the modeling process is the use of comprehensive spreadsheets for each engine case. The spreadsheets include individual worksheets for each subsystem with data, plots, and scaled figures, making the output very useful to each engineering discipline. Sample performance and sizing results with the Enabler reactor model are provided including sensitivities. Before selecting an engine design, all figures of merit must be considered including the overall impacts on the vehicle and mission. Evaluations based on key figures of merit of these results and results with the new reactor model will be performed. The impacts of clustering and external shielding will also be addressed. Over time, the reactor model will be upgraded to design and analyze other NTP concepts with CERMET and carbide fuel cores.

Bmal1 is a direct transcriptional target of the orphan nuclear receptor, NR2F1

USDA-ARS?s Scientific Manuscript database

Orphan nuclear receptor NR2F1 (also known as COUP-TFI, Chicken Ovalbumin Upstream Promoter Transcription Factor I) is a highly conserved member of the nuclear receptor superfamily. NR2F1 plays a critical role during embryonic development, particularly in the central and peripheral nervous systems a...

Nuclear criticality safety bounding analysis for the in-tank-precipitation (ITP) process, impacted by fissile isotopic weight fractions

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

Bess, C.E.

The In-Tank Precipitation process (ITP) receives High Level Waste (HLW) supernatant liquid containing radionuclides in waste processing tank 48H. Sodium tetraphenylborate, NaTPB, and monosodium titanate (MST), NaTi{sub 2}O{sub 5}H, are added for removal of radioactive Cs and Sr, respectively. In addition to removal of radio-strontium, MST will also remove plutonium and uranium. The majority of the feed solutions to ITP will come from the dissolution of supernate that had been concentrated by evaporation to a crystallized salt form, commonly referred to as saltcake. The concern for criticality safety arises from the adsorption of U and Pt onto MST. If sufficientmore » mass and optimum conditions are achieved then criticality is credible. The concentration of u and Pt from solution into the smaller volume of precipitate represents a concern for criticality. This report supplements WSRC-TR-93-171, Nuclear Criticality Safety Bounding Analysis For The In-Tank-Precipitation (ITP) Process. Criticality safety in ITP can be analyzed by two bounding conditions: (1) the minimum safe ratio of MST to fissionable material and (2) the maximum fissionable material adsorption capacity of the MST. Calculations have provided the first bounding condition and experimental analysis has established the second. This report combines these conditions with canyon facility data to evaluate the potential for criticality in the ITP process due to the adsorption of the fissionable material from solution. In addition, this report analyzes the potential impact of increased U loading onto MST. Results of this analysis demonstrate a greater safety margin for ITP operations than the previous analysis. This report further demonstrates that the potential for criticality in the ITP process due to adsorption of fissionable material by MST is not credible.« less

Vulnerability analysis and critical areas identification of the power systems under terrorist attacks

NASA Astrophysics Data System (ADS)

Wang, Shuliang; Zhang, Jianhua; Zhao, Mingwei; Min, Xu

2017-05-01

This paper takes central China power grid (CCPG) as an example, and analyzes the vulnerability of the power systems under terrorist attacks. To simulate the intelligence of terrorist attacks, a method of critical attack area identification according to community structures is introduced. Meanwhile, three types of vulnerability models and the corresponding vulnerability metrics are given for comparative analysis. On this basis, influence of terrorist attacks on different critical areas is studied. Identifying the vulnerability of different critical areas will be conducted. At the same time, vulnerabilities of critical areas under different tolerance parameters and different vulnerability models are acquired and compared. Results show that only a few number of vertex disruptions may cause some critical areas collapse completely, they can generate great performance losses the whole systems. Further more, the variation of vulnerability values under different scenarios is very large. Critical areas which can cause greater damage under terrorist attacks should be given priority of protection to reduce vulnerability. The proposed method can be applied to analyze the vulnerability of other infrastructure systems, they can help decision makers search mitigation action and optimum protection strategy.

High-intensity power-resolved radiation imaging of an operational nuclear reactor.

PubMed

Beaumont, Jonathan S; Mellor, Matthew P; Villa, Mario; Joyce, Malcolm J

2015-10-09

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors.

Design and optimization of the heat rejection system for a liquid cooled thermionic space nuclear reactor power system

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

Moriarty, M.P.

1993-01-15

The heat transport subsystem for a liquid metal cooled thermionic space nuclear power system was modelled using algorithms developed in support of previous nuclear power system study programs, which date back to the SNAP-10A flight system. The model was used to define the optimum dimensions of the various components in the heat transport subsystem subjected to the constraints of minimizing mass and achieving a launchable package that did not require radiator deployment. The resulting design provides for the safe and reliable cooling of the nuclear reactor in a proven lightweight design.

Design and optimization of the heat rejection system for a liquid cooled thermionic space nuclear reactor power system

NASA Astrophysics Data System (ADS)

Moriarty, Michael P.

1993-01-01

The heat transport subsystem for a liquid metal cooled thermionic space nuclear power system was modelled using algorithms developed in support of previous nuclear power system study programs, which date back to the SNAP-10A flight system. The model was used to define the optimum dimensions of the various components in the heat transport subsystem subjected to the constraints of minimizing mass and achieving a launchable package that did not require radiator deployment. The resulting design provides for the safe and reliable cooling of the nuclear reactor in a proven lightweight design.

Critical issues in NASA information systems

NASA Technical Reports Server (NTRS)

1987-01-01

The National Aeronautics and Space Administration has developed a globally-distributed complex of earth resources data bases since LANDSAT 1 was launched in 1972. NASA envisages considerable growth in the number, extent, and complexity of such data bases, due to the improvements expected in its remote sensing data rates, and the increasingly multidisciplinary nature of its scientific investigations. Work already has begun on information systems to support multidisciplinary research activities based on data acquired by the space station complex and other space-based and terrestrial sources. In response to a request from NASA's former Associate Administrator for Space Science and Applications, the National Research Council convened a committee in June 1985 to identify the critical issues involving information systems support to space science and applications. The committee has suggested that OSSA address four major information systems issues; centralization of management functions, interoperability of user involvement in the planning and implementation of its programs, and technology.

Radiation induced dissolution of UO 2 based nuclear fuel - A critical review of predictive modelling approaches

NASA Astrophysics Data System (ADS)

Eriksen, Trygve E.; Shoesmith, David W.; Jonsson, Mats

2012-01-01

Radiation induced dissolution of uranium dioxide (UO 2) nuclear fuel and the consequent release of radionuclides to intruding groundwater are key-processes in the safety analysis of future deep geological repositories for spent nuclear fuel. For several decades, these processes have been studied experimentally using both spent fuel and various types of simulated spent fuels. The latter have been employed since it is difficult to draw mechanistic conclusions from real spent nuclear fuel experiments. Several predictive modelling approaches have been developed over the last two decades. These models are largely based on experimental observations. In this work we have performed a critical review of the modelling approaches developed based on the large body of chemical and electrochemical experimental data. The main conclusions are: (1) the use of measured interfacial rate constants give results in generally good agreement with experimental results compared to simulations where homogeneous rate constants are used; (2) the use of spatial dose rate distributions is particularly important when simulating the behaviour over short time periods; and (3) the steady-state approach (the rate of oxidant consumption is equal to the rate of oxidant production) provides a simple but fairly accurate alternative, but errors in the reaction mechanism and in the kinetic parameters used may not be revealed by simple benchmarking. It is essential to use experimentally determined rate constants and verified reaction mechanisms, irrespective of whether the approach is chemical or electrochemical.

System Design for a Nuclear Electric Spacecraft Utilizing Out-of-core Thermionic Conversion

NASA Technical Reports Server (NTRS)

Estabrook, W. C.; Phillips, W. M.; Hsieh, T.

1976-01-01

Basic guidelines are presented for a nuclear space power system which utilizes heat pipes to transport thermal power from a fast nuclear reactor to an out of core thermionic converter array. Design parameters are discussed for the nuclear reactor, heat pipes, thermionic converters, shields (neutron and gamma), waste heat rejection systems, and the electrical bus bar-cable system required to transport the high current/low voltage power to the processing equipment. Dimensions are compatible with shuttle payload bay constraints.

Manned space flight nuclear system safety. Volume 1: base nuclear system safety

NASA Technical Reports Server (NTRS)

1972-01-01

The mission and terrestrial nuclear safety aspects of future long duration manned space missions in low earth orbit are discussed. Nuclear hazards of a typical low earth orbit Space Base mission (from natural sources and on-board nuclear hardware) have been identified and evaluated. Some of the principal nuclear safety design and procedural considerations involved in launch, orbital, and end of mission operations are presented. Areas of investigation include radiation interactions with the crew, subsystems, facilities, experiments, film, interfacing vehicles, nuclear hardware and the terrestrial populace. Results of the analysis indicate: (1) the natural space environment can be the dominant radiation source in a low earth orbit where reactors are effectively shielded, (2) with implementation of safety guidelines the reactor can present a low risk to the crew, support personnel, the terrestrial populace, flight hardware and the mission, (3) ten year missions are feasible without exceeding integrated radiation limits assigned to flight hardware, and (4) crew stay-times up to one year are feasible without storm shelter provisions.

Identification and Analysis of Critical Gaps in Nuclear Fuel Cycle Codes Required by the SINEMA Program

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

Adrian Miron; Joshua Valentine; John Christenson

2009-10-01

The current state of the art in nuclear fuel cycle (NFC) modeling is an eclectic mixture of codes with various levels of applicability, flexibility, and availability. In support of the advanced fuel cycle systems analyses, especially those by the Advanced Fuel Cycle Initiative (AFCI), Unviery of Cincinnati in collaboration with Idaho State University carried out a detailed review of the existing codes describing various aspects of the nuclear fuel cycle and identified the research and development needs required for a comprehensive model of the global nuclear energy infrastructure and the associated nuclear fuel cycles. Relevant information obtained on the NFCmore » codes was compiled into a relational database that allows easy access to various codes' properties. Additionally, the research analyzed the gaps in the NFC computer codes with respect to their potential integration into programs that perform comprehensive NFC analysis.« less

Nuclear electric propulsion: A better, safer, cheaper transportation system for human exploration of Mars

NASA Technical Reports Server (NTRS)

Clark, John S.; George, Jeffrey A.; Gefert, Leon P.; Doherty, Michael P.; Sefcik, Robert J.

1994-01-01

NASA has completed a preliminary mission and systems study of nuclear electric propulsion (NEP) systems for 'split-sprint' human exploration and related robotic cargo missions to Mars. This paper describes the study, the mission architecture selected, the NEP system and technology development needs, proposed development schedules, and estimated development costs. Since current administration policy makers have delayed funding for key technology development activities that could make Mars exploration missions a reality in the near future, NASA will have time to evaluate various alternate mission options, and it appears prudent to ensure that Mars mission plans focus on astronaut and mission safety, while reducing costs to acceptable levels. The split-sprint nuclear electric propulsion system offers trip times comparable to nuclear thermal propulsion (NTP) systems, while providing mission abort opportunities that are not possible with 'reference' mission architectures. Thus, NEP systems offer short transit times for the astronauts, reducing the exposure of the crew to intergalactic cosmic radiation. The high specific impulse of the NEP system, which leads to very low propellant requirements, results in significantly lower 'initial mass in low earth orbit' (IMLEO). Launch vehicle packaging studies show that the NEP system can be launched, assembled, and deployed, with about one less 240-metric-ton heavy lift launch vehicle (HLLV) per mission opportunity - a very Technology development cost of the nuclear reactor for an NEP system would be shared with the proposed nuclear surface power systems, since nuclear systems will be required to provide substantial electrical power on the surface of Mars. The NEP development project plan proposed includes evolutionary technology development for nuclear electric propulsion systems that expands upon SP-100 (Space Power - 100 kw(e)) technology that has been developed for lunar and Mars surface nuclear power, and small NEP systems

Preliminary Design of Critical Function Monitoring System of PGSFR

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

NONE

2015-07-01

A PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is under development at Korea Atomic Energy Research Institute. A critical function monitoring system of the PGSFR is preliminarily studied. The functions of CFMS are to display critical plant variables related to the safety of the plant during normal and accident conditions and guide the operators corrective actions to keep the plant in a safe condition and mitigate the consequences of accidents. The minimal critical functions of the PGSFR are composed of reactivity control, reactor core cooling, reactor coolant system integrity, primary heat transfer system(PHTS) heat removal, sodium water reaction mitigation, radiation controlmore » and containment conditions. The variables and alarm legs of each critical function of the PGSFR are as follows; - Reactivity control: The variables of reactivity control function are power range neutron flux instrumentation, intermediate range neutron flux instrumentation, source range neutron flux instrumentation, and control rod bottom contacts. The alarm leg to display the reactivity controls consists of status of control drop malfunction, high post trip power and thermal reactivity addition. - Reactor core cooling: The variables are PHTS sodium level, hot pool temperature of PHTS, subassembly exit temperature, cold pool temperature of the PHTS, PHTS pump current, and PHTS pump breaker status. The alarm leg consists of high core delta temperature, low sodium level of the PHTS, high subassembly exit temperature, and low PHTS pump load. - Reactor coolant system integrity: The variables are PHTS sodium level, cover gas pressure, and safeguard vessel sodium level. The alarm leg is composed of low sodium level of PHTS, high cover gas pressure and high sodium level of the safety guard vessel. - PHTS heat removal: The variables are PHTS sodium level, hot pool temperature of PHTS, core exit temperature, cold pool temperature of the PHTS, flow rate of passive residual heat removal

Nuclear receptors in bile acid metabolism

PubMed Central

Li, Tiangang; Chiang, John Y. L.

2013-01-01

Bile acids are signaling molecules that activate nuclear receptors, such as farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, and vitamin D receptor, and play a critical role in the regulation of lipid, glucose, energy, and drug metabolism. These xenobiotic/endobiotic-sensing nuclear receptors regulate phase I oxidation, phase II conjugation, and phase III transport in bile acid and drug metabolism in the digestive system. Integration of bile acid metabolism with drug metabolism controls absorption, transport, and metabolism of nutrients and drugs to maintain metabolic homeostasis and also protects against liver injury, inflammation, and related metabolic diseases, such as nonalcoholic fatty liver disease, diabetes, and obesity. Bile-acid–based drugs targeting nuclear receptors are in clinical trials for treating cholestatic liver diseases and fatty liver disease. PMID:23330546

RICIS Symposium 1992: Mission and Safety Critical Systems Research and Applications

NASA Technical Reports Server (NTRS)

1992-01-01

This conference deals with computer systems which control systems whose failure to operate correctly could produce the loss of life and or property, mission and safety critical systems. Topics covered are: the work of standards groups, computer systems design and architecture, software reliability, process control systems, knowledge based expert systems, and computer and telecommunication protocols.

Acknowledging the Infrasystem: A Critical Feminist Analysis of Systems Theory.

ERIC Educational Resources Information Center

Creedon, Pamela J.

1993-01-01

Examines the absence of a critical feminist perspective in the application of systems theory as a unifying model for public relations. Describes an unacknowledged third system, the infrasystem, that constructs both suprasystem and subsystem interactions. Concludes with a case analysis of sport as illustration. (HB)

Medical education in cyberspace: critical considerations in the health system

PubMed Central

YAZDANI, SHAHRAM; KHOSHGOFTAR, ZOHREH; AHMADY, SOLEIMAN; RASTEGARPOUR, HASSAN; FOROUTAN, SEYED ABBAS

2017-01-01

Introduction: Over the past few decades, two revolutionary approaches have emerged as a new form of medical education: Electronic Medical Education and Web-based Medical Education. A number of well-known medical institutions, such as Harvard and Johns Hopkins used a wide range of cyberspace capabilities to increase their competitiveness. Researchers have expressed that cyberspace will change health system’s main objective of training physicians and medical education. We conducted this study to identify the health system critical considerations on core issues, involving the development of medical education on cyberspace. Methods: In order to conduct this study, we observed the steps of a critical literature review, combined with the ‘Four-phase method’ adopted by Carnwell and Daly. We focused on particular literature on health and cyber system functions; it was associated with systemic approach. Results: We developed a six-level taxonomy, Cyber level, Governance level, Ministerial level, Organizational level, Program level and Performance level, as a key solution that can be applied for the success of medical education on cyberspace. The results were summarized and appraised in more details. Conclusion: Medical education on cyberspace is a complex interdisciplinary system. It is important that all aspects of the health systems be involved as integral to the development of cyber based medical education; without this convergence, we will be confused by the decisions made by others within the system. Health system should also communicate with those external sectors that are critical to achieving better learning on cyberspace. Integrated planning, governance and management of medical education in cyberspace are pivotal elements for the promotion. PMID:28124017

An Approach for Validating Actinide and Fission Product Burnup Credit Criticality Safety Analyses--Criticality (keff) Predictions

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

Scaglione, John M; Mueller, Don; Wagner, John C

2011-01-01

One of the most significant remaining challenges associated with expanded implementation of burnup credit in the United States is the validation of depletion and criticality calculations used in the safety evaluation - in particular, the availability and use of applicable measured data to support validation, especially for fission products. Applicants and regulatory reviewers have been constrained by both a scarcity of data and a lack of clear technical basis or approach for use of the data. U.S. Nuclear Regulatory Commission (NRC) staff have noted that the rationale for restricting their Interim Staff Guidance on burnup credit (ISG-8) to actinide-only ismore » based largely on the lack of clear, definitive experiments that can be used to estimate the bias and uncertainty for computational analyses associated with using burnup credit. To address the issue of validation, the NRC initiated a project with the Oak Ridge National Laboratory to (1) develop and establish a technically sound validation approach (both depletion and criticality) for commercial spent nuclear fuel (SNF) criticality safety evaluations based on best-available data and methods and (2) apply the approach for representative SNF storage and transport configurations/conditions to demonstrate its usage and applicability, as well as to provide reference bias results. The purpose of this paper is to describe the criticality (k{sub eff}) validation approach, and resulting observations and recommendations. Validation of the isotopic composition (depletion) calculations is addressed in a companion paper at this conference. For criticality validation, the approach is to utilize (1) available laboratory critical experiment (LCE) data from the International Handbook of Evaluated Criticality Safety Benchmark Experiments and the French Haut Taux de Combustion (HTC) program to support validation of the principal actinides and (2) calculated sensitivities, nuclear data uncertainties, and the limited available

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.

Clustering analysis of water distribution systems: identifying critical components and community impacts.

PubMed

Diao, K; Farmani, R; Fu, G; Astaraie-Imani, M; Ward, S; Butler, D

2014-01-01

Large water distribution systems (WDSs) are networks with both topological and behavioural complexity. Thereby, it is usually difficult to identify the key features of the properties of the system, and subsequently all the critical components within the system for a given purpose of design or control. One way is, however, to more explicitly visualize the network structure and interactions between components by dividing a WDS into a number of clusters (subsystems). Accordingly, this paper introduces a clustering strategy that decomposes WDSs into clusters with stronger internal connections than external connections. The detected cluster layout is very similar to the community structure of the served urban area. As WDSs may expand along with urban development in a community-by-community manner, the correspondingly formed distribution clusters may reveal some crucial configurations of WDSs. For verification, the method is applied to identify all the critical links during firefighting for the vulnerability analysis of a real-world WDS. Moreover, both the most critical pipes and clusters are addressed, given the consequences of pipe failure. Compared with the enumeration method, the method used in this study identifies the same group of the most critical components, and provides similar criticality prioritizations of them in a more computationally efficient time.

1985 Nuclear Science Symposium, 32nd, and 1985 Symposium on Nuclear Power Systems, 17th, San Francisco, CA, October 23-25, 1985, Proceedings

NASA Technical Reports Server (NTRS)

1986-01-01

The present conference ranges over topics in high energy physics instrumentation, detectors, nuclear medical applications, health physics and environmental monitoring, reactor instrumentation, nuclear spacecraft instrumentation, the 'Fastbus' data acquisition system, circuits and systems for nuclear research facilities, and the development status of nuclear power systems. Specific attention is given to CCD high precision detectors, a drift chamber preamplifier, a Cerenkov ring imaging detector, novel scintillation glasses and scintillating fibers, a modular multidrift vertex detector, radial wire drift chambers, liquid argon polarimeters, a multianode photomultiplier, the reliability of planar silicon detectors, the design and manufacture of wedge and strip anodes, ultrafast triode photodetectors, photomultiplier tubes, a barium fluoride plastic scintillator, a fine grained neutron hodoscope, the stability of low leakage silicon photodiodes for crystal calorimeters, and X-ray proportional counters. Also considered are positron emission tomography, single photon emission computed tomography, nuclear magnetic resonance imaging, Geiger-Muller detectors, nuclear plant safeguards, a 32-bit Fastbus computer, an advanced light water reactor, and nuclear plant maintenance.

Nuclear thermal propulsion transportation systems for lunar/Mars exploration

NASA Technical Reports Server (NTRS)

Clark, John S.; Borowski, Stanley K.; Mcilwain, Melvin C.; Pellaccio, Dennis G.

1992-01-01

Nuclear thermal propulsion technology development is underway at NASA and DoE for Space Exploration Initiative (SEI) missions to Mars, with initial near-earth flights to validate flight readiness. Several reactor concepts are being considered for these missions, and important selection criteria will be evaluated before final selection of a system. These criteria include: safety and reliability, technical risk, cost, and performance, in that order. Of the concepts evaluated to date, the Nuclear Engine for Rocket Vehicle Applications (NERVA) derivative (NDR) is the only concept that has demonstrated full power, life, and performance in actual reactor tests. Other concepts will require significant design work and must demonstrate proof-of-concept. Technical risk, and hence, development cost should therefore be lowest for the concept, and the NDR concept is currently being considered for the initial SEI missions. As lighter weight, higher performance systems are developed and validated, including appropriate safety and astronaut-rating requirements, they will be considered to support future SEI application. A space transportation system using a modular nuclear thermal rocket (NTR) system for lunar and Mars missions is expected to result in significant life cycle cost savings. Finally, several key issues remain for NTR's, including public acceptance and operational issues. Nonetheless, NTR's are believed to be the 'next generation' of space propulsion systems - the key to space exploration.

Critical care providers refer to information tools less during communication tasks after a critical care clinical information system introduction.

PubMed

Ballermann, Mark; Shaw, Nicola T; Mayes, Damon C; Gibney, R T Noel

2011-01-01

Electronic documentation methods may assist critical care providers with information management tasks in Intensive Care Units (ICUs). We conducted a quasi-experimental observational study to investigate patterns of information tool use by ICU physicians, nurses, and respiratory therapists during verbal communication tasks. Critical care providers used tools less at 3 months after the CCIS introduction. At 12 months, care providers referred to paper and permanent records, especially during shift changes. The results suggest potential areas of improvement for clinical information systems in assisting critical care providers in ensuring informational continuity around their patients.

Apoptosis leads to a degradation of vital components of active nuclear transport and a dissociation of the nuclear lamina.

PubMed

Kramer, A; Liashkovich, I; Oberleithner, H; Ludwig, S; Mazur, I; Shahin, V

2008-08-12

Apoptosis, a physiologically critical process, is characterized by a destruction of the cell after sequential degradation of key cellular components. Here, we set out to explore the fate of the physiologically indispensable nuclear envelope (NE) in this process. The NE mediates the critical nucleocytoplasmic transport through nuclear pore complexes (NPCs). In addition, the NE is involved in gene expression and contributes significantly to the overall structure and mechanical stability of the cell nucleus through the nuclear lamina, which underlies the entire nucleoplasmic face of the NE and thereby interconnects the NPCs, the NE, and the genomic material. Using the nano-imaging and mechanical probing approach atomic force microscopy (AFM) and biochemical methods, we unveiled the fate of the NE during apoptosis. The doomed NE sustains a degradation of both the mediators of the critical selective nucleocytoplasmic transport, namely NPC cytoplasmic filaments and basket, and the nuclear lamina. These observations are paralleled by marked softening and destabilization of the NE and the detection of vesicle-like nuclear fragments. We conclude that destruction of the cell nucleus during apoptosis proceeds in a strategic fashion. Degradation of NPC cytoplasmic filaments and basket shuts down the critical selective nucleocytoplasmic cross-talk. Degradation of the nuclear lamina disrupts the pivotal connection between the NE and the chromatin, breaks up the overall nuclear architecture, and softens the NE, thereby enabling the formation of nuclear fragments at later stages of apoptosis.

Shutdown system for a nuclear reactor

DOEpatents

Groh, E.F.; Olson, A.P.; Wade, D.C.; Robinson, B.W.

1984-06-05

An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion. 8 figs.

Shutdown system for a nuclear reactor

DOEpatents

Groh, Edward F.; Olson, Arne P.; Wade, David C.; Robinson, Bryan W.

1984-01-01

An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.

Contributions to Integral Nuclear Data in ICSBEP and IRPhEP since ND 2013

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

Bess, John D.; Briggs, J. Blair; Gulliford, Jim

2016-09-01

The status of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) was last discussed directly with the international nuclear data community at ND2013. Since ND2013, integral benchmark data that are available for nuclear data testing has continued to increase. The status of the international benchmark efforts and the latest contributions to integral nuclear data for testing is discussed. Select benchmark configurations that have been added to the ICSBEP and IRPhEP Handbooks since ND2013 are highlighted. The 2015 edition of the ICSBEP Handbook now contains 567 evaluations with benchmark specifications for 4,874more » critical, near-critical, or subcritical configurations, 31 criticality alarm placement/shielding configuration with multiple dose points apiece, and 207 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications. The 2015 edition of the IRPhEP Handbook contains data from 143 different experimental series that were performed at 50 different nuclear facilities. Currently 139 of the 143 evaluations are published as approved benchmarks with the remaining four evaluations published in draft format only. Measurements found in the IRPhEP Handbook include criticality, buckling and extrapolation length, spectral characteristics, reactivity effects, reactivity coefficients, kinetics, reaction-rate distributions, power distributions, isotopic compositions, and/or other miscellaneous types of measurements for various types of reactor systems. Annual technical review meetings for both projects were held in April 2016; additional approved benchmark evaluations will be included in the 2016 editions of these handbooks.« less

Design and implementation of a nuclear weapons management system submodule: Shipboard security force system. Master's thesis

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

Settlemyer, S.R.

1991-09-01

The Nuclear Weapons Management System combines the strengths of an expert system with the flexibility of a database management system to assist the Weapons Officer, Security Officer, and the Personnel Reliability Program Officer in the performance of administrative duties associated with the nuclear weapons programs in the United States Navy. This thesis examines the need for, and ultimately the design of, a system that will assist the Security Officer in administrative duties associated with the Shipboard Self Defense Force. This system, designed and coded utilizing dBASE IV, can be implemented as a stand alone system. Furthermore, it interfaces with themore » expert system submodule that handles the PRP screening process.« less

The mammalian respiratory system and critical windows of exposure for children's health.

PubMed Central

Pinkerton, K E; Joad, J P

2000-01-01

The respiratory system is a complex organ system composed of multiple cell types involved in a variety of functions. The development of the respiratory system occurs from embryogenesis to adult life, passing through several distinct stages of maturation and growth. We review embryonic, fetal, and postnatal phases of lung development. We also discuss branching morphogenesis and cellular differentiation of the respiratory system, as well as the postnatal development of xenobiotic metabolizing systems within the lungs. Exposure of the respiratory system to a wide range of chemicals and environmental toxicants during perinatal life has the potential to significantly affect the maturation, growth, and function of this organ system. Although the potential targets for exposure to toxic factors are currently not known, they are likely to affect critical molecular signals expressed during distinct stages of lung development. The effects of exposure to environmental tobacco smoke during critical windows of perinatal growth are provided as an example leading to altered cellular and physiological function of the lungs. An understanding of critical windows of exposure of the respiratory system on children's health requires consideration that lung development is a multistep process and cannot be based on studies in adults. Images Figure 1 Figure 4 PMID:10852845

Accelerator Driven Nuclear Energy: The Thorium Option

ScienceCinema

Raja, Rajendran

2018-01-05

Conventional nuclear reactors use enriched Uranium as fuel and produce nuclear waste which needs to be stored away for over 10,000 years.   At the current rate of use, existing sources of Uranium will last for 50-100 years.  We describe a solution to the problem that uses particle accelerators to produce fast neutrons that can be used to burn existing nuclear waste and produce energy.  Such systems, initially proposed by Carlo Rubbia and collaborators in the 1990's, are being seriously considered by many countries as a possible solution to the green energy problem.  Accelerator driven reactors operate in a sub-critical regime and, thus, are safer and can obtain energy from plentiful elements such as Thorium-232 and Uranium-238. What is missing is the high intensity (10MW) accelerator that produces 1 GeV protons. We will describe scenarios which if implemented will make such systems a reality.  

Study on Communication System of Social Risk Information on Nuclear Energy

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

Hidekazu Yoshikawa; Toshio Sugiman; Yasunaga Wakabayashi

2004-07-01

As a new risk communication method for the construction of effective knowledge bases about 'safety and non-anxiety for nuclear energy', a study on new communication method of social risk information by means of electronic communication has been started, by noticing rapid expansion of internet usage in the society. The purpose of this research is to enhance the public acceptance to nuclear power in Japan by the following two aspects. The first is to develop the mutual communication system among the working persons involved in both the operation and maintenance activities for nuclear power plant, by which they will exchange theirmore » daily experiences to improve the safety conscious activities to foster 'safety culture' attitude. The other is the development of an effective risk communication system between nuclear society and the general publics about the hot issues of 'what are the concerned involved in the final disposal of high-level radioactive waste?' and 'what should we do to have social consensus to deal with this issue in future'. The authors' research plan for the above purpose is summarized as shown in Table 1. As the first step of the authors' three year research project which started from August 2003, social investigation by questionnaires by internet and postal mail, have been just recently conducted on their risk perception for the nuclear power for the people engaged in nuclear business and women in the metropolitan area, respectively, in order to obtain the relevant information on how and what should be considered for constructing effective risk communication methods of social risk information between the people within nuclear industries and the general public in society. Although there need to be discussed, the contrasting risk images as shown in Fig.1, can be depicted between the nuclear people and general public these days in Japan, from the results of the social investigation. As the conclusion of the authors' study thus far conducted, the

Robustness of critical points in a complex adaptive system: Effects of hedge behavior

NASA Astrophysics Data System (ADS)

Liang, Yuan; Huang, Ji-Ping

2013-08-01

In our recent papers, we have identified a class of phase transitions in the market-directed resource-allocation game, and found that there exists a critical point at which the phase transitions occur. The critical point is given by a certain resource ratio. Here, by performing computer simulations and theoretical analysis, we report that the critical point is robust against various kinds of human hedge behavior where the numbers of herds and contrarians can be varied widely. This means that the critical point can be independent of the total number of participants composed of normal agents, herds and contrarians, under some conditions. This finding means that the critical points we identified in this complex adaptive system (with adaptive agents) may also be an intensive quantity, similar to those revealed in traditional physical systems (with non-adaptive units).

An Improved Method to Control the Critical Parameters of a Multivariable Control System

NASA Astrophysics Data System (ADS)

Subha Hency Jims, P.; Dharmalingam, S.; Wessley, G. Jims John

2017-10-01

The role of control systems is to cope with the process deficiencies and the undesirable effect of the external disturbances. Most of the multivariable processes are highly iterative and complex in nature. Aircraft systems, Modern Power Plants, Refineries, Robotic systems are few such complex systems that involve numerous critical parameters that need to be monitored and controlled. Control of these important parameters is not only tedious and cumbersome but also is crucial from environmental, safety and quality perspective. In this paper, one such multivariable system, namely, a utility boiler has been considered. A modern power plant is a complex arrangement of pipework and machineries with numerous interacting control loops and support systems. In this paper, the calculation of controller parameters based on classical tuning concepts has been presented. The controller parameters thus obtained and employed has controlled the critical parameters of a boiler during fuel switching disturbances. The proposed method can be applied to control the critical parameters like elevator, aileron, rudder, elevator trim rudder and aileron trim, flap control systems of aircraft systems.

The Nuclear Nonproliferation Treaty in Context

NASA Astrophysics Data System (ADS)

Davenport, Kelsey

2017-01-01

The 1968 Nuclear Nonproliferation Treaty (NPT) is the cornerstone of multilateral efforts to prevent the spread of nuclear weapons and promote efforts toward complete disarmament. In the grand bargain of the NPT, states foreswore pursuit of nuclear weapons in exchange for access to nuclear technology and limited nuclear arsenals to the five states (China, France, Russia, the United Kingdom and the United States) that tested such weapons before the NPT's conception. Now in its seventh decade, the NPT regime is embraced by the vast majority of the world's nations and is viewed as a critical element of international security. However, despite past successes in halting efforts in several states to pursue nuclear weapons, near universal adherence, and only one withdrawal (North Korea), the NPT regime is at a critical crossroads. The treaty has proven unable to adapt to new challenges, such as emerging technologies that threaten operational strategic realities, the devolution of state authority to non-state actors and institutions, and growing dissatisfaction with slow pace of nuclear disarmament. Additionally, the treaty leaves open critical questions, including whether or not state parties have the `right' to pursue technologies that allow for domestic production of fuels for nuclear reactors and if modernization programs for nuclear warheads are inconsistent with the treaty. If these questions remain unresolved, the international community will find itself ill prepared to confront emerging proliferation challenges and the NPT, the linchpin of international nonproliferation and disarmament efforts, may begin to erode.

Quartetting in Nuclear Matter and α Particle Condensation in Nuclear Systems

NASA Astrophysics Data System (ADS)

Röpke, G.; Schuck, P.; Horiuchi, H.; Tohsaki, A.; Funaki, Y.; Yamada, T.

2008-02-01

Alternatively to pairing, four-particle correlations may become of importance for the formation of quantum condensates in nuclear matter. With increasing density, four-particle correlations are suppressed because of Pauli blocking. Signatures of α-like clusters are expected to occur in low-density nuclear systems. The famous Hoyle state (02+ at 7.654 MeV in 12C) is identified as being an almost ideal condensate of three α-particles, hold together only by the Coulomb barrier. It, therefore, has a 8Be-α structure of low density. Transition probability and inelastic form factor together with position and other physical quantities are correctly reproduced without any adjustable parameter from our two parameter wave function of α-particle condensate type. The possibility of the existence of α-particle condensed states in heavier nα nuclei is also discussed.

What can nuclear collisions teach us about the boiling of water or the formation of multi-star systems

NASA Astrophysics Data System (ADS)

Gross, D. H. E.

2001-11-01

Phase transitions in nuclei, small atomic clusters and self-gravitating systems demand the extension of thermo-statistics to "Small" systems. The main obstacle is the thermodynamic limit. It is shown how the original definition of the entropy by Boltzmann as the volume of the energy-manifold of the N-body phase space allows a geometrical definition of the entropy as function of the conserved quantities. Without invoking the thermodynamic limit the whole "zoo" of phase transitions and critical points/lines can be unambiguously defined. The relation to the Yang-Lee singularities of the grand-canonical partition sum is pointed out. It is shown that just phase transitions in non-extensive systems give the complete set of characteristic parameters of the transition including the surface tension. Nuclear heavy-ion collisions are an experimental playground to explore this extension of thermo-statistics

[Two-nuclear neurons: sincitial fusion or amitotic division].

PubMed

Sotnikov, O S; Frumkina, L E; Lactionova, A A; Paramonova, N M; Novakovskaia, S A

2011-01-01

In the review the history of research two-nuclear neurons is stated and two hypotheses about mechanisms of their formation are analysed: by sincitial fusion or amytotic divisions. The facts of discrepancy of the former orthodox cellular theory categorically denying possibility sincitial of communications in nervous system and of sincitial fusion neurons are mentioned. As an example results of ultrastructural researches of occurrence sincitium in a cortex of the big brain of rats, in autonomic ganglions, in hypocampus and a cerebellum of adult animals are presented. The video data of the sincitial fusion of live neurons and the mechanism of formation multinuclear neurons in tissue culture are analyzed. Existing data about amytotic a way of formation two-nuclear neurons are critically considered. The conclusion becomes, that the mechanism of formation two-nuclear neurons is cellular fusion. Simultaneously the review confirms our representations about existence in nervous system sincitial interneural communications.

High-intensity power-resolved radiation imaging of an operational nuclear reactor

PubMed Central

Beaumont, Jonathan S.; Mellor, Matthew P.; Villa, Mario; Joyce, Malcolm J.

2015-01-01

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors. PMID:26450669

Additional nuclear criticality safety calculations for small-diameter containers

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

Hone, M.J.

This report documents additional criticality safety analysis calculations for small diameter containers, which were originally documented in Reference 1. The results in Reference 1 indicated that some of the small diameter containers did not meet the criteria established for criticality safety at the Portsmouth facility (K{sub eff} +2{sigma}<.95) when modeled under various contingency assumptions of reflection and moderation. The calculations performed in this report reexamine those cases which did not meet the criticality safety criteria. In some cases, unnecessary conservatism is removed, and in other cases mass or assay limits are established for use with the respective containers.

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

Nuclear Propulsion through Direct Conversion of Fusion Energy: The Fusion Driven Rocket

NASA Technical Reports Server (NTRS)

Slough, John; Pancotti, Anthony; Kirtley, David; Pihl, Christopher; Pfaff, Michael

2012-01-01

The future of manned space exploration and development of space depends critically on the creation of a dramatically more proficient propulsion architecture for in-space transportation. A very persuasive reason for investigating the applicability of nuclear power in rockets is the vast energy density gain of nuclear fuel when compared to chemical combustion energy. Current nuclear fusion efforts have focused on the generation of electric grid power and are wholly inappropriate for space transportation as the application of a reactor based fusion-electric system creates a colossal mass and heat rejection problem for space application.

An Advanced NSSS Integrity Monitoring System for Shin-Kori Nuclear Units 3 and 4

NASA Astrophysics Data System (ADS)

Oh, Yang Gyun; Galin, Scott R.; Lee, Sang Jeong

2010-12-01

The advanced design features of NSSS (Nuclear Steam Supply System) Integrity Monitoring System for Shin-Kori Nuclear Units 3 and 4 are summarized herein. During the overall system design and detailed component design processes, many design improvements have been made for the system. The major design changes are: 1) the application of a common software platform for all subsystems, 2) the implementation of remote access, control and monitoring capabilities, and 3) the equipment redesign and rearrangement that has simplified the system architecture. Changes give an effect on cabinet size, number of cables, cyber-security, graphic user interfaces, and interfaces with other monitoring systems. The system installation and operation for Shin-Kori Nuclear Units 3 and 4 will be more convenient than those for previous Korean nuclear units in view of its remote control capability, automated test functions, improved user interface functions, and much less cabling.

Building of communication system for nuclear accident emergency disposal based on IP multimedia subsystem

NASA Astrophysics Data System (ADS)

Wang, Kang; Gao, Guiqing; Qin, Yuanli; He, Xiangyong

2018-05-01

The nuclear accident emergency disposal must be supported by an efficient, real-time modularization and standardization communication system. Based on the analysis of communication system for nuclear accident emergency disposal which included many functions such as the internal and external communication, multiply access supporting and command center. Some difficult problems of the communication system were discussed such as variety access device type, complex composition, high mobility, set up quickly, multiply business support, and so on. Taking full advantages of the IP Multimedia Subsystem (IMS), a nuclear accident emergency communication system was build based on the IMS. It was studied and implemented that some key unit and module functions of communication system were included the system framework implementation, satellite access, short-wave access, load/vehicle-mounted communication units. The application tests showed that the system could provide effective communication support for the nuclear accident emergency disposal, which was of great practical value.

Critical Seismic Vector Random Excitations for Multiply Supported Structures

NASA Astrophysics Data System (ADS)

Sarkar, A.; Manohar, C. S.

1998-05-01

A method for determining critical power spectral density matrix models for earthquake excitations which maximize steady response variance of linear multiply supported extended structures and which also satisfy constraints on input variance, zero crossing rates, frequency content and transmission time lag has been developed. The optimization problem is shown to be non-linear in nature and solutions are obtained by using an iterative technique which is based on linear programming method. A constraint on entropy rate as a measure of uncertainty which can be expected in realistic earthquake ground motions is proposed which makes the critical excitations more realistic. Two special cases are also considered. Firstly, when knowledge of autospectral densities is available, the critical response is shown to be produced by fully coherent excitations which are neither in-phase nor out-of-phase. The critical phase between the excitation components depends on structural parameters, but independent of the auto-spectral densities of the excitations. Secondly, when the knowledge of autospectral densities and phase spectrum of the excitations is available, the critical response is shown to be produced by a system dependent coherence function representing neither fully coherent nor fully incoherent ground motions. The applications of these special cases are discussed in the context of land-based extended structures and secondary systems such as nuclear piping assembly. Illustrative examples on critical inputs and response of sdof and a long-span suspended cable which demonstrated the various features of the approach developed are presented.

The Integrated Safety-Critical Advanced Avionics Communication and Control (ISAACC) System Concept: Infrastructure for ISHM

NASA Technical Reports Server (NTRS)

Gwaltney, David A.; Briscoe, Jeri M.

2005-01-01

Integrated System Health Management (ISHM) architectures for spacecraft will include hard real-time, critical subsystems and soft real-time monitoring subsystems. Interaction between these subsystems will be necessary and an architecture supporting multiple criticality levels will be required. Demonstration hardware for the Integrated Safety-Critical Advanced Avionics Communication & Control (ISAACC) system has been developed at NASA Marshall Space Flight Center. It is a modular system using a commercially available time-triggered protocol, ?Tp/C, that supports hard real-time distributed control systems independent of the data transmission medium. The protocol is implemented in hardware and provides guaranteed low-latency messaging with inherent fault-tolerance and fault-containment. Interoperability between modules and systems of modules using the TTP/C is guaranteed through definition of messages and the precise message schedule implemented by the master-less Time Division Multiple Access (TDMA) communications protocol. "Plug-and-play" capability for sensors and actuators provides automatically configurable modules supporting sensor recalibration and control algorithm re-tuning without software modification. Modular components of controlled physical system(s) critical to control algorithm tuning, such as pumps or valve components in an engine, can be replaced or upgraded as "plug and play" components without modification to the ISAACC module hardware or software. ISAACC modules can communicate with other vehicle subsystems through time-triggered protocols or other communications protocols implemented over Ethernet, MIL-STD- 1553 and RS-485/422. Other communication bus physical layers and protocols can be included as required. In this way, the ISAACC modules can be part of a system-of-systems in a vehicle with multi-tier subsystems of varying criticality. The goal of the ISAACC architecture development is control and monitoring of safety critical systems of a

Safety aspects of nuclear waste disposal in space

NASA Technical Reports Server (NTRS)

Rice, E. E.; Edgecombe, D. S.; Compton, P. R.

1981-01-01

Safety issues involved in the disposal of nuclear wastes in space as a complement to mined geologic repositories are examined as part of an assessment of the feasibility of nuclear waste disposal in space. General safety guidelines for space disposal developed in the areas of radiation exposure and shielding, containment, accident environments, criticality, post-accident recovery, monitoring systems and isolation are presented for a nuclear waste disposal in space mission employing conventional space technology such as the Space Shuttle. The current reference concept under consideration by NASA and DOE is then examined in detail, with attention given to the waste source and mix, the waste form, waste processing and payload fabrication, shipping casks and ground transport vehicles, launch site operations and facilities, Shuttle-derived launch vehicle, orbit transfer vehicle, orbital operations and space destination, and the system safety aspects of the concept are discussed for each component. It is pointed out that future work remains in the development of an improved basis for the safety guidelines and the determination of the possible benefits and costs of the space disposal option for nuclear wastes.

Nuclear fuels for very high temperature applications

NASA Astrophysics Data System (ADS)

Lundberg, L. B.; Hobbins, R. R.

The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO2 or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures.

Liquid metal cooled nuclear reactor plant system

DOEpatents

Hunsbedt, Anstein; Boardman, Charles E.

1993-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting for fuel decay during reactor shutdown, or heat produced during a mishap. The reactor system is enhanced with sealing means for excluding external air from contact with the liquid metal coolant leaking from the reactor vessel during an accident. The invention also includes a silo structure which resists attack by leaking liquid metal coolant, and an added unique cooling means.

Structural and mechanistic insights into nuclear transport and delivery of the critical pluripotency factor Oct4 to DNA.

PubMed

Okuyama, Takahide; Yamagishi, Ryosuke; Shimada, Jiro; Ikeda, Masaaki; Maruoka, Yayoi; Kaneko, Hiroki

2018-02-01

Oct4 is a master regulator of the induction and maintenance of cellular pluripotency, and has crucial roles in early stages of differentiation. It is the only factor that cannot be substituted by other members of the same protein family to induce pluripotency. However, although Oct4 nuclear transport and delivery to target DNA are critical events for reprogramming to pluripotency, little is known about the molecular mechanism. Oct4 is imported to the nucleus by the classical nuclear transport mechanism, which requires importin α as an adaptor to bind the nuclear localization signal (NLS). Although there are structures of complexes of the NLS of transcription factors (TFs) in complex with importin α, there are no structures available for complexes involving intact TFs. We have therefore modeled the structure of the complex of the whole Oct4 POU domain and importin α2 using protein-protein docking and molecular dynamics. The model explains how the Ebola virus VP24 protein has a negative effect on the nuclear import of STAT1 by importin α but not on Oct4, and how Nup 50 facilitates cargo release from importin α. The model demonstrates the structural differences between the Oct4 importin α bound and DNA bound crystal states. We propose that the 'expanded linker' between the two DNA-binding domains of Oct4 is an intrinsically disordered region and that its conformational changes have a key role in the recognition/binding to both DNA and importin α. Moreover, we propose that this structural change enables efficient delivery to DNA after release from importin α.

Nuclear thermal propulsion engine system design analysis code development

NASA Astrophysics Data System (ADS)

Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.; Ivanenok, Joseph F.

1992-01-01

A Nuclear Thermal Propulsion (NTP) Engine System Design Analyis Code has recently been developed to characterize key NTP engine system design features. Such a versatile, standalone NTP system performance and engine design code is required to support ongoing and future engine system and vehicle design efforts associated with proposed Space Exploration Initiative (SEI) missions of interest. Key areas of interest in the engine system modeling effort were the reactor, shielding, and inclusion of an engine multi-redundant propellant pump feed system design option. A solid-core nuclear thermal reactor and internal shielding code model was developed to estimate the reactor's thermal-hydraulic and physical parameters based on a prescribed thermal output which was integrated into a state-of-the-art engine system design model. The reactor code module has the capability to model graphite, composite, or carbide fuels. Key output from the model consists of reactor parameters such as thermal power, pressure drop, thermal profile, and heat generation in cooled structures (reflector, shield, and core supports), as well as the engine system parameters such as weight, dimensions, pressures, temperatures, mass flows, and performance. The model's overall analysis methodology and its key assumptions and capabilities are summarized in this paper.

Nuclear Science Symposium, 4th, and Nuclear Power Systems Symposium, 9th, San Francisco, Calif., October 19-21, 1977, Proceedings

NASA Technical Reports Server (NTRS)

1978-01-01

Consideration is given to the following types of high energy physics instrumentation: drift chambers, multiwire proportional chambers, calorimeters, optical detectors, ionization and scintillation detectors, solid state detectors, and electronic and digital subsystems. Attention is also paid to reactor instrumentation, nuclear medicine instrumentation, data acquisition systems for nuclear instrumentation, microprocessor applications in nuclear science, environmental instrumentation, control and instrumentation of nuclear power generating stations, and radiation monitoring. Papers are also presented on instrumentation for the High Energy Astronomy Observatory.