Induction of polyploidy by nuclear fusion mechanism upon decreased expression of the nuclear envelope protein LAP2β in the human osteosarcoma cell line U2OS.

PubMed

Ben-Shoshan, Shirley Oren; Simon, Amos J; Jacob-Hirsch, Jasmine; Shaklai, Sigal; Paz-Yaacov, Nurit; Amariglio, Ninette; Rechavi, Gideon; Trakhtenbrot, Luba

2014-01-28

Polyploidy has been recognized for many years as an important hallmark of cancer cells. Polyploid cells can arise through cell fusion, endoreplication and abortive cell cycle. The inner nuclear membrane protein LAP2β plays key roles in nuclear envelope breakdown and reassembly during mitosis, initiation of replication and transcriptional repression. Here we studied the function of LAP2β in the maintenance of cell ploidy state, a role which has not yet been assigned to this protein. By knocking down the expression of LAP2β, using both viral and non-viral RNAi approaches in osteosarcoma derived U2OS cells, we detected enlarged nuclear size, nearly doubling of DNA content and chromosomal duplications, as analyzed by fluorescent in situ hybridization and spectral karyotyping methodologies. Spectral karyotyping analyses revealed that near-hexaploid karyotypes of LAP2β knocked down cells consisted of not only seven duplicated chromosomal markers, as could be anticipated by genome duplication mechanism, but also of four single chromosomal markers. Furthermore, spectral karyotyping analysis revealed that both of two near-triploid U2OS sub-clones contained the seven markers that were duplicated in LAP2β knocked down cells, whereas the four single chromosomal markers were detected only in one of them. Gene expression profiling of LAP2β knocked down cells revealed that up to a third of the genes exhibiting significant changes in their expression are involved in cancer progression. Our results suggest that nuclear fusion mechanism underlies the polyploidization induction upon LAP2β reduced expression. Our study implies on a novel role of LAP2β in the maintenance of cell ploidy status. LAP2β depleted U2OS cells can serve as a model to investigate polyploidy and aneuploidy formation by nuclear fusion mechanism and its involvement in cancerogenesis.

Structural basis of Brr2-Prp8 interactions and implications for U5 snRNP biogenesis and the spliceosome active site.

PubMed

Nguyen, Thi Hoang Duong; Li, Jade; Galej, Wojciech P; Oshikane, Hiroyuki; Newman, Andrew J; Nagai, Kiyoshi

2013-06-04

The U5 small nuclear ribonucleoprotein particle (snRNP) helicase Brr2 disrupts the U4/U6 small nuclear RNA (snRNA) duplex and allows U6 snRNA to engage in an intricate RNA network at the active center of the spliceosome. Here, we present the structure of yeast Brr2 in complex with the Jab1/MPN domain of Prp8, which stimulates Brr2 activity. Contrary to previous reports, our crystal structure and mutagenesis data show that the Jab1/MPN domain binds exclusively to the N-terminal helicase cassette. The residues in the Jab1/MPN domain, whose mutations in human Prp8 cause the degenerative eye disease retinitis pigmentosa, are found at or near the interface with Brr2, clarifying its molecular pathology. In the cytoplasm, Prp8 forms a precursor complex with U5 snRNA, seven Smproteins, Snu114, and Aar2, but after nuclear import, Brr2 replaces Aar2 to form mature U5 snRNP. Our structure explains why Aar2 and Brr2 are mutually exclusive and provides important insights into the assembly of U5 snRNP.

Searching for U-235m produced by Nuclear Excitation by Electronic Transition

NASA Astrophysics Data System (ADS)

Chodash, Perry; Norman, Eric; Burke, Jason; Wilks, Scott; Casperson, Robert

2014-09-01

Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The laser was focused on small samples of both depleted uranium and highly enriched uranium. The plasma conditions created by the intense laser pulse were varied by changing the spot size of the laser on the target. The resulting plasma was collected on a plate and the internal conversion electrons were focused onto a microchannel plate detector by a series of electrostatic lenses. First results will be presented. Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The laser was focused on small samples of both depleted uranium and highly enriched uranium. The plasma conditions created by the

Nuclear Excitation by Electronic Transition of U-235

NASA Astrophysics Data System (ADS)

Chodash, Perry

2017-01-01

Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is theorized to exist in numerous isotopes. NEET is the inverse of bound internal conversion and occurs when an electronic transition couples to a nuclear transition causing the nucleus to enter an excited state. This process can only occur for isotopes with low-lying nuclear levels due to the requirement that the electronic and nuclear transitions have similar energies. One of the candidate isotopes for NEET, 235U, has been studied several times over the past 40 years and NEET of 235U has never been conclusively observed. These past experiments generated conflicting results with some experiments claiming to observe NEET of 235U and others setting limits for the NEET rate. If NEET of 235U were to occur, the uranium would be excited to its first excited nuclear state. The first excited nuclear state in 235U is only 76 eV, the second lowest known nuclear state. Additionally, the 76 eV state is a nuclear isomer that decays by internal conversion with a half-life of 26 minutes. In order to measure whether NEET occurs in 235U and at what rate, a uranium plasma was required. The plasma was generated using a Q-switched Nd:YAG laser outputting 789 mJ pulses of 1064 nm light. The laser light was focused onto uranium targets generating an intensity on target of order 1012 W/cm2. The resulting plasma was captured on a catcher plate and electrons emitted from the catcher plate were accelerated and focused onto a microchannel plate detector. Measurements performed using a variety of uranium targets spanning depleted uranium up to 99.4% enriched uranium did not observe a 26 minute decay. An upper limit for the NEET rate of 235U was determined. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The U.S. DHS, UC Berkeley, the NNIS fellowship and the NSSC further supported this work.

7 CFR 51.1576 - U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large. 51.1576 Section 51.1576 Agriculture Regulations of the Department of...) United States Consumer Standards for Potatoes Grades § 51.1576 U.S. Grade B Small; U.S. Grade B Medium; U...

7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.

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... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large. 51.1575 Section 51.1575 Agriculture Regulations of the Department of...) United States Consumer Standards for Potatoes Grades § 51.1575 U.S. Grade A Small; U.S. Grade A Medium; U...

7 CFR 51.1576 - U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large. 51.1576 Section 51.1576 Agriculture Regulations of the Department of...) United States Consumer Standards for Potatoes Grades § 51.1576 U.S. Grade B Small; U.S. Grade B Medium; U...

7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.

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2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large. 51.1575 Section 51.1575 Agriculture Regulations of the Department of...) United States Consumer Standards for Potatoes Grades § 51.1575 U.S. Grade A Small; U.S. Grade A Medium; U...

7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large. 51.1575 Section 51.1575 Agriculture Regulations of the Department of... Potatoes Grades § 51.1575 U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade...

7 CFR 51.1576 - U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large. 51.1576 Section 51.1576 Agriculture Regulations of the Department of... Potatoes Grades § 51.1576 U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade...

7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large. 51.1575 Section 51.1575 Agriculture Regulations of the Department of... Potatoes Grades § 51.1575 U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade...

7 CFR 51.1576 - U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large. 51.1576 Section 51.1576 Agriculture Regulations of the Department of... Potatoes Grades § 51.1576 U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade...

7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large. 51.1575 Section 51.1575 Agriculture Regulations of the Department of... Potatoes Grades § 51.1575 U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade...

7 CFR 51.1576 - U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade B Large. 51.1576 Section 51.1576 Agriculture Regulations of the Department of... Potatoes Grades § 51.1576 U.S. Grade B Small; U.S. Grade B Medium; U.S. Grade B Medium to Large; U.S. Grade...

49 CFR 173.471 - Requirements for U.S. Nuclear Regulatory Commission approved packages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Requirements for U.S. Nuclear Regulatory...) Materials § 173.471 Requirements for U.S. Nuclear Regulatory Commission approved packages. In addition to the applicable requirements of the U.S. Nuclear Regulatory Commission (NRC) and other requirements of...

49 CFR 173.471 - Requirements for U.S. Nuclear Regulatory Commission approved packages.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Requirements for U.S. Nuclear Regulatory...) Materials § 173.471 Requirements for U.S. Nuclear Regulatory Commission approved packages. In addition to the applicable requirements of the U.S. Nuclear Regulatory Commission (NRC) and other requirements of...

49 CFR 173.471 - Requirements for U.S. Nuclear Regulatory Commission approved packages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Requirements for U.S. Nuclear Regulatory...) Materials § 173.471 Requirements for U.S. Nuclear Regulatory Commission approved packages. In addition to the applicable requirements of the U.S. Nuclear Regulatory Commission (NRC) and other requirements of...

49 CFR 173.471 - Requirements for U.S. Nuclear Regulatory Commission approved packages.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Requirements for U.S. Nuclear Regulatory...) Materials § 173.471 Requirements for U.S. Nuclear Regulatory Commission approved packages. In addition to the applicable requirements of the U.S. Nuclear Regulatory Commission (NRC) and other requirements of...

Identification of U2AF(35)-dependent exons by RNA-Seq reveals a link between 3′ splice-site organization and activity of U2AF-related proteins

PubMed Central

Kralovicova, Jana; Knut, Marcin; Cross, Nicholas C. P.; Vorechovsky, Igor

2015-01-01

The auxiliary factor of U2 small nuclear RNA (U2AF) is a heterodimer consisting of 65- and 35-kD proteins that bind the polypyrimidine tract (PPT) and AG dinucleotides at the 3′ splice site (3′ss). The gene encoding U2AF35 (U2AF1) is alternatively spliced, giving rise to two isoforms U2AF35a and U2AF35b. Here, we knocked down U2AF35 and each isoform and characterized transcriptomes of HEK293 cells with varying U2AF35/U2AF65 and U2AF35a/b ratios. Depletion of both isoforms preferentially modified alternative RNA processing events without widespread failure to recognize 3′ss or constitutive exons. Over a third of differentially used exons were terminal, resulting largely from the use of known alternative polyadenylation (APA) sites. Intronic APA sites activated in depleted cultures were mostly proximal whereas tandem 3′UTR APA was biased toward distal sites. Exons upregulated in depleted cells were preceded by longer AG exclusion zones and PPTs than downregulated or control exons and were largely activated by PUF60 and repressed by CAPERα. The U2AF(35) repression and activation was associated with a significant interchange in the average probabilities to form single-stranded RNA in the optimal PPT and branch site locations and sequences further upstream. Although most differentially used exons were responsive to both U2AF subunits and their inclusion correlated with U2AF levels, a small number of transcripts exhibited distinct responses to U2AF35a and U2AF35b, supporting the existence of isoform-specific interactions. These results provide new insights into function of U2AF and U2AF35 in alternative RNA processing. PMID:25779042

Human regulator of telomere elongation helicase 1 (RTEL1) is required for the nuclear and cytoplasmic trafficking of pre-U2 RNA

PubMed Central

Schertzer, Michael; Jouravleva, Karina; Perderiset, Mylene; Dingli, Florent; Loew, Damarys; Le Guen, Tangui; Bardoni, Barbara; de Villartay, Jean-Pierre; Revy, Patrick; Londoño-Vallejo, Arturo

2015-01-01

Hoyeraal-Hreidarsson syndrome (HHS) is a severe form of Dyskeratosis congenita characterized by developmental defects, bone marrow failure and immunodeficiency and has been associated with telomere dysfunction. Recently, mutations in Regulator of Telomere ELongation helicase 1 (RTEL1), a helicase first identified in Mus musculus as being responsible for the maintenance of long telomeres, have been identified in several HHS patients. Here we show that RTEL1 is required for the export and the correct cytoplasmic trafficking of the small nuclear (sn) RNA pre-U2, a component of the major spliceosome complex. RTEL1-HHS cells show abnormal subcellular partitioning of pre-U2, defects in the recycling of ribonucleotide proteins (RNP) in the cytoplasm and splicing defects. While most of these phenotypes can be suppressed by re-expressing the wild-type protein in RTEL1-HHS cells, expression of RTEL1 mutated variants in immortalized cells provokes cytoplasmic mislocalizations of pre-U2 and other RNP components, as well as splicing defects, thus phenocopying RTEL1-HHS cellular defects. Strikingly, expression of a cytoplasmic form of RTEL1 is sufficient to correct RNP mislocalizations both in RTEL1–HHS cells and in cells expressing nuclear mutated forms of RTEL1. This work unravels completely unanticipated roles for RTEL1 in RNP trafficking and strongly suggests that defects in RNP biogenesis pathways contribute to the pathology of HHS. PMID:25628358

Human regulator of telomere elongation helicase 1 (RTEL1) is required for the nuclear and cytoplasmic trafficking of pre-U2 RNA.

PubMed

Schertzer, Michael; Jouravleva, Karina; Perderiset, Mylene; Dingli, Florent; Loew, Damarys; Le Guen, Tangui; Bardoni, Barbara; de Villartay, Jean-Pierre; Revy, Patrick; Londoño-Vallejo, Arturo

2015-02-18

Hoyeraal-Hreidarsson syndrome (HHS) is a severe form of Dyskeratosis congenita characterized by developmental defects, bone marrow failure and immunodeficiency and has been associated with telomere dysfunction. Recently, mutations in Regulator of Telomere ELongation helicase 1 (RTEL1), a helicase first identified in Mus musculus as being responsible for the maintenance of long telomeres, have been identified in several HHS patients. Here we show that RTEL1 is required for the export and the correct cytoplasmic trafficking of the small nuclear (sn) RNA pre-U2, a component of the major spliceosome complex. RTEL1-HHS cells show abnormal subcellular partitioning of pre-U2, defects in the recycling of ribonucleotide proteins (RNP) in the cytoplasm and splicing defects. While most of these phenotypes can be suppressed by re-expressing the wild-type protein in RTEL1-HHS cells, expression of RTEL1 mutated variants in immortalized cells provokes cytoplasmic mislocalizations of pre-U2 and other RNP components, as well as splicing defects, thus phenocopying RTEL1-HHS cellular defects. Strikingly, expression of a cytoplasmic form of RTEL1 is sufficient to correct RNP mislocalizations both in RTEL1-HHS cells and in cells expressing nuclear mutated forms of RTEL1. This work unravels completely unanticipated roles for RTEL1 in RNP trafficking and strongly suggests that defects in RNP biogenesis pathways contribute to the pathology of HHS. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

The Nuclear Renaissance in the U.S.

ScienceCinema

Buongiorno, Jacopo

2018-04-23

Nuclear power currently provides 20% of the electricity generation in the U.S. and about 16% worldwide.  As a carbon-free energy source, nuclear is receiving a lot of attention by industry, lawmakers and environmental groups, as they attempt to resolve the issue of man-made climate change.  For the first time in 30 years several U.S. electric utilities have applied for construction and operation licenses of new nuclear power plants.  This talk will review the safety, operational and economic record of the existing U.S. commercial reactor fleet, will provide an overview of the reactor designs considered for the new wave of plant construction, and will discuss several research projects being conducted at the Massachusetts Institute of Technology to support the expansion of nuclear power in the U.S. and overseas.

77 FR 8943 - U.S. Small Business Administration.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-15

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77 FR 70847 - Entergy Nuclear Indian Point 2, LLC; Entergy Nuclear Operations, Inc., Indian Point Nuclear...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-27

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Characterization of the Human Herpesvirus 6 U69 Gene Product and Identification of Its Nuclear Localization Signal▿

PubMed Central

Isegawa, Yuji; Miyamoto, Yoichi; Yasuda, Yoshinari; Semi, Katsunori; Tsujimura, Kenji; Fukunaga, Rikiro; Ohshima, Atsushi; Horiguchi, Yasuhiro; Yoneda, Yoshihiro; Sugimoto, Nakaba

2008-01-01

To elucidate the function of the U69 protein kinase of human herpesvirus 6 (HHV-6) in vivo, we first analyzed its subcellular localization in HHV-6-infected Molt 3 cells by using polyclonal antibodies against the U69 protein. Immunofluorescence studies showed that the U69 signal localized to the nucleus in a mesh-like pattern in both HHV-6-infected and HHV6-transfected cells. A computer program predicted two overlapping classic nuclear localization signals (NLSs) in the N-terminal region of the protein; this NLS motif is highly conserved in the N-terminal region of most of the herpesvirus protein kinases examined to date. An N-terminal deletion mutant form of the protein failed to enter the nucleus, whereas a fusion protein of green fluorescent protein (GFP) and/or glutathione S-transferase (GST) and the U69 N-terminal region was transported into the nucleus, demonstrating that the predicted N-terminal NLSs of the protein actually function as NLSs. The nuclear transport of the GST-GFP fusion protein containing the N-terminal NLS of U69 was inhibited by wheat germ agglutinin and by the Q69L Ran-GTP mutant, indicating that the U69 protein is transported into the nucleus from the cytoplasm via classic nuclear transport machinery. A cell-free import assay showed that the nuclear transport of the U69 protein was mediated by importin α/β in conjunction with the small GTPase Ran. When the import assay was performed with a low concentration of each importin-α subtype, NPI2/importin-α7 elicited more efficient transport activity than did Rch1/importin-α1 or Qip1/importin-α3. These results suggest a relationship between the localization of NPI2/importin-α7 and the cell tropism of HHV-6. PMID:18003734

Epitope mapping of the U1 small nuclear ribonucleoprotein particle in patients with systemic lupus erythematosus and mixed connective tissue disease.

PubMed

Somarelli, J A; Mesa, A; Rodriguez, R; Avellan, R; Martinez, L; Zang, Y J; Greidinger, E L; Herrera, R J

2011-03-01

Systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are autoimmune illnesses characterized by the presence of high titers of autoantibodies directed against a wide range of 'self ' antigens. Proteins of the U1 small nuclear ribonucleoprotein particle (U1 snRNP) are among the most immunogenic molecules in patients with SLE and MCTD. The recent release of a crystallized U1 snRNP provides a unique opportunity to evaluate the effects of tertiary and quaternary structures on autoantigenicity within the U1 snRNP. In the present study, an epitope map was created using the U1 snRNP crystal structure. A total of 15 peptides were tested in a cohort of 68 patients with SLE, 29 with MCTD and 26 healthy individuals and mapped onto the U1 snRNP structure. Antigenic sites were detected in a variety of structures and appear to include RNA binding domains, but mostly exclude regions necessary for protein-protein interactions. These data suggest that while some autoantibodies may target U1 snRNP proteins as monomers or apoptosis-induced, protease-digested fragments, others may recognize epitopes on assembled protein subcomplexes of the U1 snRNP. Although nearly all of the peptides are strong predictors of autoimmune illness, none were successful at distinguishing between SLE and MCTD. The antigenicity of some peptides significantly correlated with several clinical symptoms. This investigation implicitly highlights the complexities of autoimmune epitopes, and autoimmune illnesses in general, and demonstrates the variability of antigens in patient populations, all of which contribute to difficult clinical diagnoses.

Nuclear Resonance Fluorescence of U-235

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

Warren, Glen A.; Caggiano, Joseph A.; Hensley, Walter K.

Nuclear resonance fluorescence is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. One isotope of significant interest is 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct measurements to search for a nuclear resonance fluorescence response of 235U below 3 MeV using a 200 g samplemore » of highly enriched uranium. Nine 235U resonances between 1650 and 2010 keV were identified in the preliminary analysis. Analysis of the measurement data to determine the integrated cross sections of the resonances is in progress.« less

Projected Costs of U.S. Nuclear Forces, 2017 to 2026

DTIC Science & Technology

2017-02-01

CBO FEBRUARY 2017 Projected Costs of U.S. Nuclear Forces, 2017 to 2026 Nuclear weapons have been a cornerstone of U.S. national security since they...were developed during World War II. In the Cold War, nuclear forces were central to U.S. defense policy, resulting in the buildup of a large...arsenal. Since that time, nuclear forces have figured less prominently than conventional forces, and the United States has not built any new nuclear

Rearrangement of competing U2 RNA helices within the spliceosome promotes multiple steps in splicing

PubMed Central

Perriman, Rhonda J.; Ares, Manuel

2007-01-01

Nuclear pre-messenger RNA (pre-mRNA) splicing requires multiple spliceosomal small nuclear RNA (snRNA) and pre-mRNA rearrangements. Here we reveal a new snRNA conformational switch in which successive roles for two competing U2 helices, stem IIa and stem IIc, promote distinct splicing steps. When stem IIa is stabilized by loss of stem IIc, rapid ATP-independent and Cus2p-insensitive prespliceosome formation occurs. In contrast, hyperstabilized stem IIc improves the first splicing step on aberrant branchpoint pre-mRNAs and rescues temperature-sensitive U6–U57C, a U6 mutation that also suppresses first-step splicing defects of branchpoint mutations. A second, later role for stem IIa is revealed by its suppression of a cold-sensitive allele of the second-step splicing factor PRP16. Our data expose a spliceosomal progression cycle of U2 stem IIa formation, disruption by stem IIc, and then reformation of stem IIa before the second catalytic step. We propose that the competing stem IIa and stem IIc helices are key spliceosomal RNA elements that optimize juxtaposition of the proper reactive sites during splicing. PMID:17403781

The future of U.S.-Russia nuclear arms control

NASA Astrophysics Data System (ADS)

Pifer, Steven

2017-11-01

Nuclear arms control has long made contributions to U.S.-Soviet and U.S.-Russian security, but the current regime is at risk. The 1987 Intermediate-range Nuclear Forces Treaty may be headed for collapse. Both the United States and Russia are modernizing their strategic forces, and the fate of the 2010 New Strategic Arms Reduction Treaty is unclear. In the unlikely case that the sides are prepared to go beyond New START, there are ways to address further reductions and related issues. A collapse of the arms control regime, on the other hand, would mean the end of constraints on U.S. and Russian nuclear forces, a significant loss of transparency, and potential costs to U.S. security.

U1 small nuclear ribonucleoprotein particle-specific proteins interact with the first and second stem-loops of U1 RNA, with the A protein binding directly to the RNA independently of the 70K and Sm proteins.

PubMed Central

Patton, J R; Habets, W; van Venrooij, W J; Pederson, T

1989-01-01

The U1 small nuclear ribonucleoprotein particle (U1 snRNP), a cofactor in pre-mRNA splicing, contains three proteins, termed 70K, A, and C, that are not present in the other spliceosome-associated snRNPs. We studied the binding of the A and C proteins to U1 RNA, using a U1 snRNP reconstitution system and an antibody-induced nuclease protection technique. Antibodies that reacted with the A and C proteins induced nuclease protection of the first two stem-loops of U1 RNA in reconstituted U1 snRNP. Detailed analysis of the antibody-induced nuclease protection patterns indicated the existence of relatively long-range protein-protein interactions in the U1 snRNP, with the 5' end of U1 RNA and its associated specific proteins interacting with proteins bound to the Sm domain near the 3' end. UV cross-linking experiments in conjunction with an A-protein-specific antibody demonstrated that the A protein bound directly to the U1 RNA rather than assembling in the U1 snRNP exclusively via protein-protein interactions. This conclusion was supported by additional experiments revealing that the A protein could bind to U1 RNA in the absence of bound 70K and Sm core proteins. Images PMID:2529425

Gene targeting of Gemin2 in mice reveals a correlation between defects in the biogenesis of U snRNPs and motoneuron cell death

PubMed Central

Jablonka, Sibylle; Holtmann, Bettina; Meister, Gunter; Bandilla, Michael; Rossoll, Wilfried; Fischer, Utz; Sendtner, Michael

2002-01-01

Neuronal degeneration in spinal muscular atrophy is caused by reduced expression of the survival motor neuron (SMN) protein. SMN and the tightly interacting Gemin2 form part of a macromolecular complex (SMN complex) that mediates assembly of spliceosomal small nuclear ribonucleoproteins (U snRNPs). We used mouse genetics to investigate the function of this complex in motoneuron maintenance. Reduced Smn/Gemin2 protein levels lead to disturbed U snRNP assembly as indicated by reduced nuclear accumulation of Sm proteins. This finding correlates with enhanced motoneuron degeneration in Gemin2+/−/Smn+/− mice. Our data provide in vivo evidence that impaired production of U snRNPs contributes to motoneuron degeneration. PMID:12091709

The United Arab Emirates Nuclear Program and Proposed U.S. Nuclear Cooperation

DTIC Science & Technology

2009-07-17

global efforts to prevent nuclear proliferation” and, “the establishment of reliable sources of nuclear fuel for future civilian light water reactors ...planned nuclear reactor or on handling spent reactor fuel. (...continued) May 4, 2008...contracting between U.S. firms and the UAE related to the UAE’s proposed nuclear program has already taken place. In August 2008, Virginia’s Thorium Power

Microstructure of the irradiated U 3Si 2/Al silicide dispersion fuel

NASA Astrophysics Data System (ADS)

Gan, J.; Keiser, D. D.; Miller, B. D.; Jue, J.-F.; Robinson, A. B.; Madden, J. W.; Medvedev, P. G.; Wachs, D. M.

2011-12-01

The silicide dispersion fuel of U 3Si 2/Al is recognized as the best performance fuel for many nuclear research and test reactors with up to 4.8 gU/cm 3 fuel loading. An irradiated U 3Si 2/Al dispersion fuel ( 235U ˜ 75%) from the high-flux side of a fuel plate (U0R040) from the Reduced Enrichment for Research and Test Reactors (RERTR)-8 test was characterized using transmission electron microscopy (TEM). The fuel was irradiated in the Advanced Test Reactor (ATR) for 105 days. The average irradiation temperature and fission density of the U 3Si 2 fuel particles for the TEM sample are estimated to be approximately 110 °C and 5.4 × 10 27 f/m 3. The characterization was performed using a 200-kV TEM. The U/Si ratio for the fuel particle and (Si + Al)/U for the fuel-matrix-interaction layer are approximately 1.1 and 4-10, respectively. The estimated average diameter, number density and volume fraction for small bubbles (<1 μm) in the fuel particle are ˜94 nm, 1.05 × 10 20 m -3 and ˜11%, respectively. The results and their implication on the performance of the U 3Si 2/Al silicide dispersion fuel are discussed.

Accurate 238U(n , 2 n )237U reaction cross-section measurements from 6.5 to 14.8 MeV

NASA Astrophysics Data System (ADS)

Krishichayan, Bhike, M.; Tornow, W.; Tonchev, A. P.; Kawano, T.

2017-10-01

The cross section for the 238U(n ,2 n )237U reaction has been measured in the incident neutron energy range from 6.5 to 14.8 MeV in small energy steps using an activation technique. Monoenergetic neutron beams were produced via the 2H(d ,n )3He and 3H(d ,n )4He reactions. 238U targets were activated along with Au and Al monitor foils to determine the incident neutron flux. The activity of the reaction products was measured in TUNL's low-background counting facility using high-resolution γ -ray spectroscopy. The results are compared with previous measurements and latest data evaluations. Statistical-model calculations, based on the Hauser-Feshbach formalism, have been carried out using the CoH3 code and are compared with the experimental results. The present self-consistent and high-quality data are important for stockpile stewardship and nuclear forensic purposes as well as for the design and operation of fast reactors.

76 FR 31997 - Final Memorandum of Understanding Between the U.S. Nuclear Regulatory Commission and the U.S...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... NUCLEAR REGULATORY COMMISSION [NRC-2011-0118] Final Memorandum of Understanding Between the U.S. Nuclear Regulatory Commission and the U.S. Department of Homeland Security on Chemical Facility Anti-Terrorism Standards AGENCY: Nuclear Regulatory Commission. ACTION: Notice of availability. FOR FURTHER...

Nuclear excitation by electronic transition of 235U

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

Chodash, P. A.; Norman, E. B.; Burke, J. T.

Here, nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that can occur in isotopes containing a low-lying nuclear excited state. Over the past 40 yr, several experiments have attempted to measure NEET of 235U and those experiments have yielded conflicting results.

Nuclear excitation by electronic transition of 235U

DOE PAGES

Chodash, P. A.; Norman, E. B.; Burke, J. T.; ...

2016-03-11

Here, nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that can occur in isotopes containing a low-lying nuclear excited state. Over the past 40 yr, several experiments have attempted to measure NEET of 235U and those experiments have yielded conflicting results.

Feasibility of Nuclear Power on U.S. Military Installations. 2nd Revision

DTIC Science & Technology

2011-03-01

Small Modular Reactor , Military Installation Energy, Energy Assurance 16. SECURITY CLASSIFICATION OF: a. REPORT I b. ABSTRACT U c. THIS PAGE i; 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 98 19a. NAME OF RESPONSIBLE PERSON Knowledge Center/Rhea Stone 19b. TELEPHONE NUMBER (Include area code) 703-824-2110 Standard Form 298 (Rev. 8/98) Prescribed bv ANSI Sid 239.18 Contents Preliminary note: Development and commercial deployment of small modular reactors

77 FR 40091 - Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating, Units 2 and 3

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2012-07-06

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-247 and 50-286; NRC-2008-0672] Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating, Units 2 and 3 AGENCY: Nuclear Regulatory Commission... renewal of nuclear plants; availability. SUMMARY: The U.S. Nuclear Regulatory Commission (NRC or the...

Nuclear reactor for breeding U.sup.233

DOEpatents

Bohanan, Charles S.; Jones, David H.; Raab, Jr., Harry F.; Radkowsky, Alvin

1976-01-01

A light-water-cooled nuclear reactor capable of breeding U.sup.233 for use in a light-water breeder reactor includes physically separated regions containing U.sup.235 fissile material and U.sup.238 fertile material and Th.sup.232 fertile material and Pu.sup.239 fissile material, if available. Preferably the U.sup.235 fissile material and U.sup.238 fertile material are contained in longitudinally movable seed regions and the Pu.sup.239 fissile material and Th.sup.232 fertile material are contained in blanket regions surrounding the seed regions.

Supporting U.S. Response to the Japanese Nuclear Crisis | ORAU

ScienceCinema

Crapo, John; Jakubowski, Ted

2018-05-01

When an earthquake and tsunami hit off the coast of Japan on March 11, 2011, and triggered a nuclear crisis, the U.S. immediately offered support. Among those tapped to assist was ORAU's National Security and Emergency Management team, which provided NNSA with technical and analytical nuclear incident support. Within 48 hours of the earthquake, ORAU emergency management experts accompanied the DOE Office of Emergency Response in deploying to Japan to support the U.S. Air Force Base in Yokota and the U.S. Embassy. A separate team from ORAU supported the NNSA Nuclear Incident Team, which served as the point of coordination for all support activities both in Japan and in the U.S.

Differential immunoglobulin class-mediated responses to components of the U1 small nuclear ribonucleoprotein particle in systemic lupus erythematosus and mixed connective tissue disease.

PubMed

Mesa, A; Somarelli, J A; Wu, W; Martinez, L; Blom, M B; Greidinger, E L; Herrera, R J

2013-11-01

The objective of this paper is to determine whether patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) possess differential IgM- and IgG-specific reactivity against peptides from the U1 small nuclear ribonucleoprotein particle (U1 snRNP). The IgM- and IgG-mediated responses against 15 peptides from subunits of the U1 snRNP were assessed by indirect enzyme linked immunosorbent assays (ELISAs) in sera from patients with SLE and MCTD and healthy individuals (n = 81, 41, and 31, respectively). Additionally, 42 laboratory tests and 40 clinical symptoms were evaluated to uncover potential differences. Binomial logistic regression analyses (BLR) were performed to construct models to support the independent nature of SLE and MCTD. Receiver operating characteristic (ROC) curves corroborated the classification power of the models. We analyzed IgM and IgG anti-U1 snRNP titers to classify SLE and MCTD patients. IgG anti-U1 snRNP reactivity segregates SLE and MCTD from nondisease controls with an accuracy of 94.1% while IgM-specific anti-U1 snRNP responses distinguish SLE from MCTD patients with an accuracy of 71.3%. Comparison of the IgG and IgM anti-U1 snRNP approach with clinical tests used for diagnosing SLE and MCTD revealed that our method is the best classification tool of those analyzed (p ≤ 0.0001). Our IgM anti-U1 snRNP system along with lab tests and symptoms provide additional molecular and clinical evidence to support the hypothesis that SLE and MCTD may be distinct syndromes.

10 CFR Appendix A to Part 73 - U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses A Appendix A to Part 73 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS Pt. 73, App. A Appendix A to Part 73—U.S. Nuclear Regulatory Commission...

10 CFR Appendix A to Part 73 - U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses A Appendix A to Part 73 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS Pt. 73, App. A Appendix A to Part 73—U.S. Nuclear Regulatory Commission...

10 CFR Appendix A to Part 73 - U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses A Appendix A to Part 73 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS Pt. 73, App. A Appendix A to Part 73—U.S. Nuclear Regulatory Commission...

10 CFR Appendix A to Part 73 - U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses A Appendix A to Part 73 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS Pt. 73, App. A Appendix A to Part 73—U.S. Nuclear Regulatory Commission...

10 CFR Appendix A to Part 73 - U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false U.S. Nuclear Regulatory Commission Offices and Classified Mailing Addresses A Appendix A to Part 73 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PHYSICAL PROTECTION OF PLANTS AND MATERIALS Pt. 73, App. A Appendix A to Part 73—U.S. Nuclear Regulatory Commission...

Non-stoichiometry in U 3Si 2

DOE PAGES

Middleburgh, Simon C.; Grimes, Robin W.; Lahoda, Ed J.; ...

2016-10-08

Uranium silicides, in particular U 3Si 2, are being explored as an advanced nuclear fuel with increased accident tolerance as well as competitive economics compared to the baseline UO 2 fuel. Here we use density functional theory calculations and thermochemical analysis to assess the stability of U 3Si 2 with respect to non-stoichiometry reactions in both the hypo- and hyper-stoichiometric regimes. We find that the degree of non-stoichiometry in U 3Si 2 is much smaller than in UO 2 and at most reaches a few percent at high temperature. Non-stoichiometry impacts fuel performance by determining whether the loss of uraniummore » due to fission leads to a non-stoichiometric U 3Si 2±x phase or precipitation of a second U-Si phase. Lastly, we also investigate the U 5Si 4 phase as a candidate for the equilibrium phase diagram.« less

Search for Nuclear Excitation by Electronic Transition in U-235

NASA Astrophysics Data System (ADS)

Chodash, P. A.; Norman, E. B.; Burke, J. T.; Wilks, S. C.; Casperson, R. J.; Swanberg, E. L.; Wakeling, M. A.; Cordeiro, T. J.

2013-10-01

Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The plasma was collected on a plate and the internal conversion electrons were focused onto a microchannel plate detector by a series of electrostatic lenses. Depleted uranium and highly enriched uranium samples were used for the experiment. Preliminary results will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This work was further supported by the U.S. DHS, UC Berkeley, and the NNIS Fellowship.

Planning U.S. General Purpose Forces: The Theater Nuclear Forces

DTIC Science & Technology

1977-01-01

usefulness in combat. All U.S. nuclear weapons deployed in Europe are fitted with Permissive Action Links (PAL), coded devices designed to impede...may be proposed. The Standard Missile 2, the Harpoon missile, the Mk48 tor- pedo , and the SUBROC anti-submarine rocket are all being considered for...Permissive Action Link . A coded device attached to nuclear weapons deployed abroad that impedes the unauthorized arming or firing of the weapon. Pershing

The small molecule Mek1/2 inhibitor U0126 disrupts the chordamesoderm to notochord transition in zebrafish.

PubMed

Hawkins, Thomas A; Cavodeassi, Florencia; Erdélyi, Ferenc; Szabó, Gábor; Lele, Zsolt

2008-04-17

Key molecules involved in notochord differentiation and function have been identified through genetic analysis in zebrafish and mice, but MEK1 and 2 have so far not been implicated in this process due to early lethality (Mek1-/-) and functional redundancy (Mek2-/-) in the knockout animals. Here, we reveal a potential role for Mek1/2 during notochord development by using the small molecule Mek1/2 inhibitor U0126 which blocks phosphorylation of the Mek1/2 target gene Erk1/2 in vivo. Applying the inhibitor from early gastrulation until the 18-somite stage produces a specific and consistent phenotype with lack of dark pigmentation, shorter tail and an abnormal, undulated notochord. Using morphological analysis, in situ hybridization, immunhistochemistry, TUNEL staining and electron microscopy, we demonstrate that in treated embryos the chordamesoderm to notochord transition is disrupted and identify disorganization in the medial layer of the perinotochordal basement mebrane as the probable cause of the undulations and bulges in the notochord. We also examined and excluded FGF as the upstream signal during this process. Using the small chemical U0126, we have established a novel link between MAPK-signaling and notochord differentiation. Our phenotypic analysis suggests a potential connection between the MAPK-pathway, the COPI-mediated intracellular transport and/or the copper-dependent posttranslational regulatory processes during notochord differentiation.

U.S. Strategic Nuclear Forces: Background, Developments, and Issues

DTIC Science & Technology

2017-02-10

Department of Energy questioned the management practices at the National Nuclear Security Administration (NNSA), which is responsible for the LEP, arguing...U.S. Strategic Nuclear Forces: Background, Developments, and Issues Amy F. Woolf Specialist in Nuclear Weapons Policy February 10, 2017...

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

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

Bruce G. Schnitzler

Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selectedmore » over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse ({approx}900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal alloy fuel types were pursued. The primary and significantly larger Rover/NERVA program focused on graphite type fuels. Research, development, and testing of high temperature graphite fuels was conducted. Reactors and engines employing these fuels were designed, built, and ground tested. The GE-710 and ANL programs focused on an alternative ceramic-metallic 'cermet' fuel type consisting of UO2 (or UN) fuel embedded in a refractory metal matrix such as tungsten. The General Electric program examined closed loop concepts for space or terrestrial

78 FR 39018 - Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 2 and 3

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-247 and 50-286; NRC-2008-0672] Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 2 and 3 AGENCY: Nuclear Regulatory Commission... Renewal of Nuclear Plants; issuance. SUMMARY: Notice is hereby given that the U.S. Nuclear Regulatory...

U.S. Nuclear Cooperation with India: Issues for Congress

DTIC Science & Technology

2010-05-27

in 2009,” Panorama , February 6, 2009. “Chennai Daily Report: India, Kazakhstan Set To Sign Nuclear Reactor Export Deal,” Chennai Business Line Online...than 5 MW thermal or special nuclear material connected therewith. . U.S. Nuclear Cooperation with India: Issues for Congress Congressional

U.S. Nuclear Cooperation with India: Issues for Congress

DTIC Science & Technology

2010-10-28

India in 2009,” Panorama , February 6, 2009. “Chennai Daily Report: India, Kazakhstan Set To Sign Nuclear Reactor Export Deal,” Chennai Business Line...MW thermal or special nuclear material connected therewith. U.S. Nuclear Cooperation with India: Issues for Congress Congressional Research

U.S. Nuclear Cooperation with India: Issues for Congress

DTIC Science & Technology

2010-04-08

Kazakhstan might start uranium exports to India in 2009,” Panorama , February 6, 2009. “Chennai Daily Report: India, Kazakhstan Set To Sign Nuclear Reactor...reactors producing more than 5 MW thermal or special nuclear material connected therewith. U.S. Nuclear Cooperation with India: Issues for Congress

Mass and abundance 236U sensitivities at CIRCE

NASA Astrophysics Data System (ADS)

De Cesare, M.; De Cesare, N.; D'Onofrio, A.; Fifield, L. K.; Gialanella, L.; Terrasi, F.

2015-10-01

The actinides (e.g. 236U and xPu isotopes) are present in environmental samples at the ultra trace level since atmospheric tests of NWs (Nuclear Weapons) performed in the past, deliberate dumping of nuclear waste, nuclear fuel reprocessing, on a large scale and operation of NPPs (Nuclear Power Plants) on a small scale have led to the release of a wide range of radioactive nuclides in the environment. Their detection requires the most sensitive AMS (Accelerator Mass Spectrometry) techniques and at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) in Caserta, Italy, an upgraded actinide AMS system, based on a 3-MV pelletron tandem accelerator, has been operated. In this paper the progress made in order to push the 236U mass sensitivity and 236U/238U isotopic ratio down to the natural levels is reported. A uranium contamination mass of about 0.05 μg and a 236U/238U isotopic ratio sensitivities at the level of 3.2 × 10-13 are presently achievable.

U-PuO2, U-PuC, U-PuN cermet fuel for fast reactor

NASA Astrophysics Data System (ADS)

Mishra, Sudhir; Kaity, Santu; Banerjee, Joydipta; Nandi, Chiranjeet; Dey, G. K.; Khan, K. B.

2018-02-01

Cermet fuel combines beneficial properties of both ceramic and metal and attracts global interest for research as a candidate fuel for nuclear reactors. In the present study, U matrix PuC/PuN/PuO2 cermet for fast reactor have been fabricated on laboratory scale by the powder metallurgy route. Characterization of the fuel has been carried out using Dilatometer, Differential Thermal analysis (DTA), X-ray diffractometer and Optical microscope. X ray diffraction study of the fuel reveals presence of different phases. The PuN dispersed cermet was observed to have high solidus temperature as compared to PuC and PuO2 dispersed cermet. Swelling was observed in U matrix PuO2 cermet which also showed higher thermal expansion. Among the three cermets studied, U matrix PuC cermet showed maximum thermal conductivity.

Spark plasma sintering and microstructural analysis of pure and Mo doped U3Si2 pellets

NASA Astrophysics Data System (ADS)

Lopes, Denise Adorno; Benarosch, Anna; Middleburgh, Simon; Johnson, Kyle D.

2017-12-01

U3Si2 has been considered as an alternative fuel for Light Water Reactors (LWRs) within the Accident Tolerant Fuels (ATF) initiative, begun after the Fukushima-Daiichi Nuclear accidents. Its main advantages are high thermal conductivity and high heavy metal density. Despite these benefits, U3Si2 presents an anisotropic crystallographic structure and low solubility of fission products, which can result in undesirable effects under irradiation conditions. In this paper, spark plasma sintering (SPS) of U3Si2 pellets is studied, with evaluation of the resulting microstructure. Additionally, exploiting the short sintering time in SPS, a molybdenum doped pellet was produced to investigate the early stages of the Mo-U3Si2 interaction, and analyze how this fission product is accommodated in the fuel matrix. The results show that pellets of U3Si2 with high density (>95% TD) can be obtained with SPS in the temperature range of 1200°C-1300 °C. Moreover, the short time employed in this technique was found to generate a unique microstructure for this fuel, composed mainly of closed nano-pores (<1 μm) and small average grain size (∼4.5 μm). The addition of Mo (1.5 at%) demonstrated no solubility of Mo in the U3Si2 matrix. The interaction of this fission product with the fuel matrix at 1200 °C formed, in the early stages, the stoichiometric U2Mo3Si4 ternary as well as precipitates of free uranium with small quantities of dissolved Si and Mo at the front of the reaction.

77 FR 41454 - Entergy Nuclear Indian Point Unit 2, LLC, Entergy Nuclear Indian Point Unit 3, LLC, Entergy...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-247 and 50-286; NRC-2012-0168] Entergy Nuclear Indian Point Unit 2, LLC, Entergy Nuclear Indian Point Unit 3, LLC, Entergy Nuclear Operations, Inc., Indian Point Nuclear Generating Units 2 and 3; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC...

The gene for human U2 snRNP auxiliary factor small 35-kDa subunit (U2AF1) maps to the progressive myoclonus epilepsy (EPM1) critical region on chromosome 21q22.3

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

Lalioti, M.D.; Rossier, C.; Antonarakis, S.E.

1996-04-15

We used targeted exon trapping to clone portions of genes from human chromosome 21q22.3. One trapped sequence showed complete homology with the cDNA of human U2AF{sup 35} (M96982; HGM-approved nomenclature U2AF1), which encodes for the small 35-kDa subunit of the U2 snRNP auxiliary factor. Using the U2AF1 cDNA as a probe, we mapped this gene to cosmid Q15D2, a P1, and YAC 350F7 of the Chumakov et al. contig, close to the cystathionine-{beta}-synthase gene (CBS) on 21q22.3. This localization was confirmed by PCR using oligonucleotides from the 3{prime} UTR and by FISH. As U2AF1 associated with a number of differentmore » factors during mRNA splicing, overexpression in trisomy 21 individuals could contribute to some Down syndrome phenotypes by interfering with the splicing process. Furthermore, because this gene maps in the critical region for the progressive myoclonus epilepsy I locus (EPM1), mutation analysis will be carried out in patients to evaluate the potential role of U2AF1 as a candidate for EPM1. 24 refs., 1 fig.« less

U.S. Strategic Nuclear Forces: Background, Developments, and Issues

DTIC Science & Technology

2013-10-22

32 Safety, Security, and Management ...by Amy F. Woolf. 2 Natural Resources Defense Council. Table of U.S. Strategic Offensive Force Loadings. Archive of Nuclear Data. http://www.nrdc.org...12000 14000 16000 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 Year N um be r Launchers Warheads Source: Natural Resources Defense Council

The Future of the U.S. Nuclear Weapons Program

NASA Astrophysics Data System (ADS)

Brooks, Linton F.

2007-03-01

This paper will examine our plans for the future of the U.S. nuclear weapons program including efforts to ``transform'' the stockpile and supporting infrastructure. We proceed from the premise that the United States will need a safe, secure, and reliable nuclear deterrent for the foreseeable future. Moreover, the Stockpile Stewardship Program is working. Today's stockpile---comprised of legacy warheads left over from the Cold War---is safe and reliable. That said, we see increased risk, absent nuclear testing, in assuring the long-term safety and reliability of our current stockpile. Nor is today's nuclear weapons complex sufficiently ``responsive'' to fixing technical problems in the stockpile, or to potential adverse geopolitical change. Our task is to work to ensure that the U.S. nuclear weapons enterprise, including the stockpile and supporting infrastructure, meets long-term national security needs. Our approach is to develop and field replacement warheads for the legacy stockpile---so-called Reliable Replacement Warheads (RRW)---as a means to transform both the nuclear stockpile and supporting infrastructure.

The U. S. nuclear industry; A changing complexion

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

Zorpette, G

This article addresses the changes which have occurred in the U.S. nuclear industry as a response to the decline in the construction of new plants. The author focuses on the segments of the industry which chiefly design and produce nuclear power plants, the architect-engineers and the suppliers, and how they have become more service oriented in response to the construction decline. The movement toward diversification to non-nuclear industries is also discussed.

A Nuclear Energy Renaissance in the U.S.?

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

Kessler, Carol E.; Mahy, Heidi A.; Ankrum, Al

2008-01-01

Is it time for a nuclear energy renaissance? Among other things, nuclear power is a carbon neutral source of base load power. With the growth in energy use expected over the next 20 years and the growing negative impacts of global climate changes, the cost of oil and gas, energy security and diversity concerns, and progress on advanced reactor designs, it may be the right time for nuclear power to enter a new age of growth. Asia and Russia are both planning for a nuclear renaissance. In Europe, Finland and France have both taken steps to pursue new nuclear reactors.more » U.S. utilities are preparing for orders of new reactors; one submitted a request to the U.S. Nuclear Regulatory Commission (NRC) to review its request to construct a new reactor on an existing site. What has the industry been doing since nuclear energy was birthed in the 1960s? In those days a bold new industry boasted that nuclear power in the United States was going to be “too cheap to meter”, but as we all know this did not come about for many reasons. Eventually, it became clear that industry had neglected to do its homework. Critiques of the industry were made on safety, security, environment, economic competitiveness (without government support), and nonproliferation. All of these factors need to be effectively addressed to promote the confidence and support of the public – without which a nuclear power program is not feasible.« less

The nuclear cap-binding complex interacts with the U4/U6·U5 tri-snRNP and promotes spliceosome assembly in mammalian cells

PubMed Central

Pabis, Marta; Neufeld, Noa; Steiner, Michaela C.; Bojic, Teodora; Shav-Tal, Yaron; Neugebauer, Karla M.

2013-01-01

The nuclear cap-binding complex (CBC) binds to the 7-methyl guanosine cap present on every RNA polymerase II transcript. CBC has been implicated in many aspects of RNA biogenesis; in addition to roles in miRNA biogenesis, nonsense-mediated decay, 3′-end formation, and snRNA export from the nucleus, CBC promotes pre-mRNA splicing. An unresolved question is how CBC participates in splicing. To investigate CBC’s role in splicing, we used mass spectrometry to identify proteins that copurify with mammalian CBC. Numerous components of spliceosomal snRNPs were specifically detected. Among these, three U4/U6·U5 snRNP proteins (hBrr2, hPrp4, and hPrp31) copurified with CBC in an RNA-independent fashion, suggesting that a significant fraction of CBC forms a complex with the U4/U6·U5 snRNP and that the activity of CBC might be associated with snRNP recruitment to pre-mRNA. To test this possibility, CBC was depleted from HeLa cells by RNAi. Chromatin immunoprecipitation and live-cell imaging assays revealed decreased cotranscriptional accumulation of U4/U6·U5 snRNPs on active transcription units, consistent with a requirement for CBC in cotranscriptional spliceosome assembly. Surprisingly, recruitment of U1 and U2 snRNPs was also affected, indicating that RNA-mediated interactions between CBC and snRNPs contribute to splicing. On the other hand, CBC depletion did not impair snRNP biogenesis, ruling out the possibility that decreased snRNP recruitment was due to changes in nuclear snRNP concentration. Taken together, the data support a model whereby CBC promotes pre-mRNA splicing through a network of interactions with and among spliceosomal snRNPs during cotranscriptional spliceosome assembly. PMID:23793891

On the Search for Nuclear Resonance Fluorescence Signatures of 235U and 238U above 3 MeV

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

Warren, Glen A.; Caggiano, Joseph A.; Bertozzi, William

Nuclear resonance fluorescence is a physical process that provides an isotope-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample that is exposed to MeV-energy photons. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials such as 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct a pair of measurements to search for a nuclear resonance fluorescence response of 235U above 3 MeV and of 238U above 5 MeV using an 8 gmore » sample of highly enriched uranium and a 90 g sample of depleted uranium. No new signatures were observed. The minimum detectable integrated cross section for 235U is presented.« less

Administrator Highlights U.S.-Georgian Nuclear Security Cooperation in Tbilisi

ScienceCinema

Thomas D'Agostino

2017-12-09

NNSA Administrator Thomas D'Agostino highlighted the strong U.S.-Georgian cooperation on nuclear security issues during a day-long visit to the Republic of Georgia in mid-June. He briefed the media at availability at the Tbilisi airport. In April 2009, President Obama outlined an ambitious agenda to secure vulnerable nuclear material around the world within four years, calling the danger of a terrorist acquiring nuclear weapons "the most immediate and extreme threat to global security." In this year's State of the Union, he called the threat of nuclear weapons, "the greatest danger to the American people." In order to meet that challenge, the President's FY2011 Budget Request includes close to $2.7 billion for the National Nuclear Security Administration's Defense Nuclear Nonproliferation program -- an increase of 25.7 percent over FY2010. Included in that request is NNSA's Second Line of Defense (SLD) program, which works around the world to strengthen the capability of foreign governments to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime shipping system.

Fanconi anemia FANCD2 and FANCI proteins regulate the nuclear dynamics of splicing factors.

PubMed

Moriel-Carretero, María; Ovejero, Sara; Gérus-Durand, Marie; Vryzas, Dimos; Constantinou, Angelos

2017-12-04

Proteins disabled in the cancer-prone disorder Fanconi anemia (FA) ensure the maintenance of chromosomal stability during DNA replication. FA proteins regulate replication dynamics, coordinate replication-coupled repair of interstrand DNA cross-links, and mitigate conflicts between replication and transcription. Here we show that FANCI and FANCD2 associate with splicing factor 3B1 (SF3B1), a key spliceosomal protein of the U2 small nuclear ribonucleoprotein (U2 snRNP). FANCI is in close proximity to SF3B1 in the nucleoplasm of interphase and mitotic cells. Furthermore, we find that DNA replication stress induces the release of SF3B1 from nuclear speckles in a manner that depends on FANCI and on the activity of the checkpoint kinase ATR. In chromatin, both FANCD2 and FANCI associate with SF3B1, prevent accumulation of postcatalytic intron lariats, and contribute to the timely eviction of splicing factors. We propose that FANCD2 and FANCI contribute to the organization of functional domains in chromatin, ensuring the coordination of DNA replication and cotranscriptional processes. © 2017 Moriel-Carretero et al.

On the Search for Nuclear Resonance Fluorescence Signatures of 235U and 238U above 3 MeV

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

Warren, Glen A.; Caggiano, Joseph A.; Bertozzi, William

Abstract–Nuclear resonance fluorescence is a physical process that provides an isotope-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample that is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials such as 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct a a pair of measurements to search for a nuclear resonance fluorescence response of 235U above 3 MeV and of 238U above 5more » MeV using an 8 g sample of highly enriched uranium and a 90 g sample of depleted uranium. No new signatures were observed. The minimum detectable integrated cross section for 235U is presented.« less

Structural basis for dual roles of Aar2p in U5 snRNP assembly

PubMed Central

Weber, Gert; Cristão, Vanessa F.; Santos, Karine F.; Jovin, Sina Mozaffari; Heroven, Anna C.; Holton, Nicole; Lührmann, Reinhard; Beggs, Jean D.; Wahl, Markus C.

2013-01-01

Yeast U5 small nuclear ribonucleoprotein particle (snRNP) is assembled via a cytoplasmic precursor that contains the U5-specific Prp8 protein but lacks the U5-specific Brr2 helicase. Instead, pre-U5 snRNP includes the Aar2 protein not found in mature U5 snRNP or spliceosomes. Aar2p and Brr2p bind competitively to a C-terminal region of Prp8p that comprises consecutive RNase H-like and Jab1/MPN-like domains. To elucidate the molecular basis for this competition, we determined the crystal structure of Aar2p in complex with the Prp8p RNase H and Jab1/MPN domains. Aar2p binds on one side of the RNase H domain and extends its C terminus to the other side, where the Jab1/MPN domain is docked onto a composite Aar2p–RNase H platform. Known Brr2p interaction sites of the Jab1/MPN domain remain available, suggesting that Aar2p-mediated compaction of the Prp8p domains sterically interferes with Brr2p binding. Moreover, Aar2p occupies known RNA-binding sites of the RNase H domain, and Aar2p interferes with binding of U4/U6 di-snRNA to the Prp8p C-terminal region. Structural and functional analyses of phospho-mimetic mutations reveal how phosphorylation reduces affinity of Aar2p for Prp8p and allows Brr2p and U4/U6 binding. Our results show how Aar2p regulates both protein and RNA binding to Prp8p during U5 snRNP assembly. PMID:23442228

How to find the optimal partner--studies of snurportin 1 interactions with U snRNA 5' TMG-cap analogues containing modified 2-amino group of 7-methylguanosine.

PubMed

Piecyk, Karolina; Niedzwiecka, Anna; Ferenc-Mrozek, Aleksandra; Lukaszewicz, Maciej; Darzynkiewicz, Edward; Jankowska-Anyszka, Marzena

2015-08-01

Snurportin 1 is an adaptor protein that mediates the active nuclear import of uridine-rich small nuclear RNAs (U snRNA) by the importin-β receptor pathway. Its cellular activity influences the overall transport yield of small ribonucleoprotein complexes containing N(2),N(2),7-trimethylguanosine (TMG) capped U snRNA. So far little is still known about structural requirements related to molecular recognition of the trimethylguanosine moiety by snurportin in solution. Since these interactions are of a great biomedical importance, we synthesized a series of new 7-methylguanosine cap analogues with extended substituents at the exocyclic 2-amino group to gain a deeper insight into how the TMG-cap is adapted into the snurportin cap-binding pocket. Prepared chemical tools were applied in binding assays using emission spectroscopy. Surprisingly, our results revealed strict selectivity of snurportin towards the TMG-cap structure that relied mainly on its structural stiffness and compactness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Administrator Highlights U.S.-Georgian Nuclear Security Cooperation in Tbilisi

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

Thomas D'Agostino

2010-07-16

NNSA Administrator Thomas D'Agostino highlighted the strong U.S.-Georgian cooperation on nuclear security issues during a day-long visit to the Republic of Georgia in mid-June. He briefed the media at availability at the Tbilisi airport. In April 2009, President Obama outlined an ambitious agenda to secure vulnerable nuclear material around the world within four years, calling the danger of a terrorist acquiring nuclear weapons "the most immediate and extreme threat to global security." In this year's State of the Union, he called the threat of nuclear weapons, "the greatest danger to the American people." In order to meet that challenge, themore » President's FY2011 Budget Request includes close to $2.7 billion for the National Nuclear Security Administration's Defense Nuclear Nonproliferation program -- an increase of 25.7 percent over FY2010. Included in that request is NNSA's Second Line of Defense (SLD) program, which works around the world to strengthen the capability of foreign governments to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime shipping system.« less

75 FR 14639 - Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 1, 2, and 3...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-26

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-003, 50-247, and 50-286; NRC-2010-0137] Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 1, 2, and 3; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption, pursuant to Title 10 of...

75 FR 69137 - Southern Nuclear Operating Company Inc. Edwin I. Hatch Nuclear Plant, Unit No. 2 Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-10

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-366; NRC-2010-0345] Southern Nuclear Operating Company Inc. Edwin I. Hatch Nuclear Plant, Unit No. 2 Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering the issuance of an exemption from Title 10 of the Code of Federal Regulations, ...

Multi-unit Operations in Non-Nuclear Systems: Lessons Learned for Small Modular Reactors

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

OHara J. M.; Higgins, J.; DAgostino, A.

2012-01-17

The nuclear-power community has reached the stage of proposing advanced reactor designs to support power generation for decades to come. Small modular reactors (SMRs) are one approach to meet these energy needs. While the power output of individual reactor modules is relatively small, they can be grouped to produce reactor sites with different outputs. Also, they can be designed to generate hydrogen, or to process heat. Many characteristics of SMRs are quite different from those of current plants and may be operated quite differently. One difference is that multiple units may be operated by a single crew (or a singlemore » operator) from one control room. The U.S. Nuclear Regulatory Commission (NRC) is examining the human factors engineering (HFE) aspects of SMRs to support licensing reviews. While we reviewed information on SMR designs to obtain information, the designs are not completed and all of the design and operational information is not yet available. Nor is there information on multi-unit operations as envisioned for SMRs available in operating experience. Thus, to gain a better understanding of multi-unit operations we sought the lesson learned from non-nuclear systems that have experience in multi-unit operations, specifically refineries, unmanned aerial vehicles and tele-intensive care units. In this paper we report the lessons learned from these systems and the implications for SMRs.« less

75 FR 77920 - Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 2 and 3; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-14

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-247 and 50-286; NRC-2008-0672] Entergy Nuclear Operations, Inc.; Indian Point Nuclear Generating Unit Nos. 2 and 3; Notice of Availability of the Final Supplement 38 to the Generic Environmental Impact Statement for License Renewal of Nuclear Plants Notice is hereby given that the U.S. Nuclear...

Nuclear resonance fluorescence in U-238 using LaBr detectors for nuclear security

NASA Astrophysics Data System (ADS)

Hayakawa, Takehito; Negm, Hani; Ohgaki, Hideaki; Daito, Izuru; Kii, Toshiteru; Zen, Heishun; Omer, Mohamed; Shizuma, Toshiyuki; Hajima, Ryoichi

2014-09-01

Recently, a nondestructive measurement method of shielded fissional isotopes such as 235U or 239Pu has been proposed for the nuclear security. These isotopes are measured by using nuclear resonance fluorescence (NRF) with monochromatic energy gamma-ray beams generated by laser Compton-scattering (LCS). We have proposed that one measure scattered gamma-rays from NRF with LCS gamma-ray beams using the LaBr3(Ce) detectors. The LaBr3(Ce) crystals include internal radioisotopes of a meta-stable isotope 138La and alpha decay chains from some actinides as 227Ac. There is a broad pump at about 2 MeV. This pump is considered to be an overlap of alpha-rays from decay chains of some actinides but its detailed structure has not been established. Here we have measured NRF spectra of 238U using the LCS gamma-rays with energy of about 2.5 MeV at the HIgS facility of the Duke University. The background has been evaluated using a simulation code GEAT4. The 9 peaks, 8 NRF gamma-rays plus the Compton scattered gamma-ray of the incident beam, are finally assigned in an energy range of about 200 keV at about 2.5 MeV. The 8 integrated NRF cross-sections measured by LaBr3(Ce) have been consistent with results by an HPGe detector. The three levels are newly assigned using the HPGe detector. Two of them are also measured by LaBr3(Ce).

75 FR 3761 - Southern Nuclear Operating Company, Inc., Edwin I. Hatch Nuclear Plant, Units 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-22

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-321 and 50-366; NRC-2010-0024] Southern Nuclear Operating Company, Inc., Edwin I. Hatch Nuclear Plant, Units 1 and 2; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an Exemption, pursuant to Title 10 of the Code of...

The new NCPSS BL19U2 beamline at the SSRF for small-angle X-ray scattering from biological macromolecules in solution.

PubMed

Li, Na; Li, Xiuhong; Wang, Yuzhu; Liu, Guangfeng; Zhou, Ping; Wu, Hongjin; Hong, Chunxia; Bian, Fenggang; Zhang, Rongguang

2016-10-01

The beamline BL19U2 is located in the Shanghai Synchrotron Radiation Facility (SSRF) and is its first beamline dedicated to biological material small-angle X-ray scattering (BioSAXS). The electrons come from an undulator which can provide high brilliance for the BL19U2 end stations. A double flat silicon crystal (111) monochromator is used in BL19U2, with a tunable monochromatic photon energy ranging from 7 to 15 keV. To meet the rapidly growing demands of crystallographers, biochemists and structural biologists, the BioSAXS beamline allows manual and automatic sample loading/unloading. A Pilatus 1M detector (Dectris) is employed for data collection, characterized by a high dynamic range and a short readout time. The highly automated data processing pipeline SASFLOW was integrated into BL19U2, with help from the BioSAXS group of the European Molecular Biology Laboratory (EMBL, Hamburg), which provides a user-friendly interface for data processing. The BL19U2 beamline was officially opened to users in March 2015. To date, feedback from users has been positive and the number of experimental proposals at BL19U2 is increasing. A description of the new BioSAXS beamline and the setup characteristics is given, together with examples of data obtained.

Synthesis and properties of ApU analogues containing 2'-halo-2'-deoxyadenosines. Effects of 2' substituents on oligonucleotide conformation.

PubMed

Uesugi, S; Kaneyasu, T; Ikehara, M

1982-11-09

Five A-U analogues containing deoxyadenosine or 2'-halo-2'-deoxyadenosines, which are known to have widely different C3'-endo conformer populations according to their electronegativities of the halogen substituents, dAfl-U, dAcl-U, dAbr-U, dAio-U, and dA-U, were synthesized chemically. Characterization of these dimers has been performed by UV absorption, circular dichroism, and proton nuclear magnetic resonance spectroscopy. The results show that the dimers containing 2'-halo-2'-deoxyadenosines have stacked conformations with a geometry similar to that of A-U and the degree of stacking decreases in the order dAfl-U greater than dAcl-U greater than dAbr-U greater than dAio-U. dAcl-U is assumed to have the same degree of stacking as A-U. dA-U takes a more stacked conformation than does dAio-U, but the mode of stacking is different from those of the other dimers. The effects of the 2' substituents on dimer conformation are discussed in terms of electronegativity, molecular size, and hydrophobicity.

Concerted evolution of the tandem array encoding primate U2 snRNA occurs in situ, without changing the cytological context of the RNU2 locus.

PubMed Central

Pavelitz, T; Rusché, L; Matera, A G; Scharf, J M; Weiner, A M

1995-01-01

In primates, the tandemly repeated genes encoding U2 small nuclear RNA evolve concertedly, i.e. the sequence of the U2 repeat unit is essentially homogeneous within each species but differs somewhat between species. Using chromosome painting and the NGFR gene as an outside marker, we show that the U2 tandem array (RNU2) has remained at the same chromosomal locus (equivalent to human 17q21) through multiple speciation events over > 35 million years leading to the Old World monkey and hominoid lineages. The data suggest that the U2 tandem repeat, once established in the primate lineage, contained sequence elements favoring perpetuation and concerted evolution of the array in situ, despite a pericentric inversion in chimpanzee, a reciprocal translocation in gorilla and a paracentric inversion in orang utan. Comparison of the 11 kb U2 repeat unit found in baboon and other Old World monkeys with the 6 kb U2 repeat unit in humans and other hominids revealed that an ancestral U2 repeat unit was expanded by insertion of a 5 kb retrovirus bearing 1 kb long terminal repeats (LTRs). Subsequent excision of the provirus by homologous recombination between the LTRs generated a 6 kb U2 repeat unit containing a solo LTR. Remarkably, both junctions between the human U2 tandem array and flanking chromosomal DNA at 17q21 fall within the solo LTR sequence, suggesting a role for the LTR in the origin or maintenance of the primate U2 array. Images PMID:7828589

Nuclear Coexistence: Rethinking U.S. Policy to Promote Stability in an Era of Proliferation

DTIC Science & Technology

1994-04-01

The Spread of Nuclear Weapons 1989 -90 (Boulder: Westview Press, 1990). 22. See William C. Martel and Steven E. Miller, "Controlling Borders and Nuclear...Security, Fall 1989 , Vol. 14, No. 2, pp. 140-41, for J. Robert Oppenheimer’s concerns about the dangers of the develop- ment of thermonuclear weapons. 4...Paradox of Technology," International Security, Vol. 14, No. 2 (Fall 1989 ), pp. 198-202. 6. Some argue that the U.S. strategy has relatively little

Initial Microstructure Evaluation of a U3Si2 + W Fuel Pin Fabricated Via Arc Melt Gravity Drop Casting

NASA Astrophysics Data System (ADS)

Hoggan, Rita E.; Harp, Jason M.

2018-02-01

Injection casting has historically been used to fabricate metallic nuclear fuel on a large scale. Casting of intermetallic fuel forms, such as U3Si2, may be an alternative pathway for fabrication of fuel pins to powder metallurgy. To investigate casting on a small scale, arc melt gravity drop casting was employed to cast a one-off pin of U3Si2 for evaluation as a fabrication method for U3Si2 as a light water reactor fuel. The pin was sectioned and examined via optical microscopy and scanning electron microscopy equipped with energy dispersive x-ray spectroscopy (EDS). Image analysis was used to estimate the volume fraction of phase impurities as well as porosity. The primary phase determined by EDS was U3Si2 with U-O and U-Si-W phase impurities. Unusually high levels of tungsten were observed because of accidental tungsten introduction during arc melting. No significant changes in microstructure were observed after annealing a section of the pin at 800°C for 72 h. The average density of the sectioned specimens was 12.4 g/cm3 measured via Archimedes principle immersion density and He gas displacement.

U.S.-Pakistani Nuclear Relations: A Strategic Survey

DTIC Science & Technology

2014-04-01

nuclear   renaissance  at  a  time   when  the   Fukushima   disaster  has  cooled  the...together,  these  trends  have   triggered   U.S.-­‐Pakistani  debate  in  four  key  subject  areas:    (1)   nuclear ...academic  literature  on  South  Asia,  but  Track  II  gatherings  have  explored   several  

History of U.S. Nuclear Weapons Doctrine and a Path Forward

NASA Astrophysics Data System (ADS)

Chyba, Christopher

2007-04-01

During the Cold War, the United States considered a number of approaches for living in a world with nuclear weapons, including disarmament, preventive war, the incorporation of nuclear weapons into military strategy, passive and active defense, and deterrence. With the failure of early approaches to disarmament, and the rejection of preventive war against the Soviet Union (and later, China), deterrence became central to key nuclear relationships, though arms control continued to play an important role. The nuclear nonproliferation treaty made preventing the further spread of nuclear weapons another central component of U.S. policy. The Bush Administration has tried to devise a new policy for the post-Cold War period. Their approach has three salient pillars. First, it is characterized by an overall skepticism toward multilateral agreements, on the grounds that bad actors will not obey them, that agreements can lead to a false sense of security, and that such agreements are too often a way for the Lilliputians of the world to tie down Gulliver. The March 2005 U.S. National Defense Strategy declared that U.S. strength ``will continue to be challenged by those who employ a strategy of the weak, using international fora, judicial processes and terrorism.'' Second, the Bush Administration declared its intention to maintain a military dominance so great that other states simply would not try to catch up. The 2002 National Security Strategy states that ``Our forces will be strong enough to dissuade potential adversaries from pursuing a military build-up in hopes of surpassing, or equaling, the power of the United States.'' Third, the 2002 National Security Strategy (reaffirmed by the 2006 National Security Strategy) moved preventive war (which the strategies called ``preemptive war'') to a central position, rather than deterrence and nonproliferation. In part this was because of the claim that certain ``rogue'' states, and terrorist groups, were not deterrable. This talk

The splicing factor U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis

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

Kim, Jeonghee; Chung, In Kwon, E-mail: topoviro@yonsei.ac.kr

Highlights: •Identification of U2AF65 as a novel TRF1-interacting protein. •U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. •U2AF65 interferes with the interaction between TRF1 and Fbx4. •U2AF65 represents a new route for modulating TRF1 function at telomeres. -- Abstract: The human telomeric protein TRF1 is a component of the six-subunit protein complex shelterin, which provides telomere protection by organizing the telomere into a high-order structure. TRF1 functions as a negative regulator of telomere length by controlling the access of telomerase to telomeres. Thus, the cellular abundance of TRF1 at telomeres should be maintained and tightly regulated to ensure propermore » telomere function. Here, we identify U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor 65 (U2AF65), an essential pre-mRNA splicing factor, as a novel TRF1-interacting protein. U2AF65 interacts with TRF1 in vitro and in vivo and is capable of stabilizing TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. We also found that U2AF65 interferes with the interaction between TRF1 and Fbx4, an E3 ubiquitin ligase for TRF1. Depletion of endogenous U2AF65 expression by short interfering RNA (siRNA) reduced the stability of endogenous TRF1 whereas overexpression of U2AF65 significantly extended the half-life of TRF1. These findings demonstrate that U2AF65 plays a critical role in regulating the level of TRF1 through physical interaction and ubiquitin-mediated proteolysis. Hence, U2AF65 represents a new route for modulating TRF1 function at telomeres.« less

A U.S. Multicenter Study of Recorded Occupational Radiation Badge Doses in Nuclear Medicine.

PubMed

Villoing, Daphnée; Yoder, R Craig; Passmore, Christopher; Bernier, Marie-Odile; Kitahara, Cari M

2018-05-01

Purpose To summarize occupational badge doses recorded for a sample of U.S. nuclear medicine technologists. Materials and Methods Nine large U.S. medical institutions identified 208 former and current nuclear medicine technologists certified after 1979 and linked these individuals to historic badge dose records maintained by a commercial dosimetry company (Landauer), yielding a total of 2618 annual dose records. The distributions of annual and cumulative occupational doses were described by using summary statistics. Results Between 1992 and 2015, the median annual personal dose equivalent per nuclear medicine technologist was 2.18 mSv (interquartile range [IQR], 1.25-3.47 mSv; mean, 2.69 mSv). Median annual personal dose equivalents remained relatively constant over this period (range, 1.40-3.30 mSv), while maximum values generally increased over time (from 8.00 mSv in 1992 to 13.9 mSv in 2015). The median cumulative personal dose equivalent was 32.9 mSv (IQR, 18.1-65.5 mSv; mean, 51.4 mSv) for 45 technologists who had complete information and remained employed through 2015. Conclusion Occupational radiation doses were well below the established occupational limits and were consistent with those observed for nuclear medicine technologists worldwide and were greater than those observed for nuclear and general medical workers in the United States These results should be informative for radiation monitoring and safety efforts in nuclear medicine departments. © RSNA, 2018 Online supplemental material is available for this article.

Evidence that C9ORF72 Dipeptide Repeat Proteins Associate with U2 snRNP to Cause Mis-splicing in ALS/FTD Patients.

PubMed

Yin, Shanye; Lopez-Gonzalez, Rodrigo; Kunz, Ryan C; Gangopadhyay, Jaya; Borufka, Carl; Gygi, Steven P; Gao, Fen-Biao; Reed, Robin

2017-06-13

Hexanucleotide repeat expansion in the C9ORF72 gene results in production of dipeptide repeat (DPR) proteins that may disrupt pre-mRNA splicing in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients. At present, the mechanisms underlying this mis-splicing are not understood. Here, we show that addition of proline-arginine (PR) and glycine-arginine (GR) toxic DPR peptides to nuclear extracts blocks spliceosome assembly and splicing, but not other types of RNA processing. Proteomic and biochemical analyses identified the U2 small nuclear ribonucleoprotein particle (snRNP) as a major interactor of PR and GR peptides. In addition, U2 snRNP, but not other splicing factors, mislocalizes from the nucleus to the cytoplasm both in C9ORF72 patient induced pluripotent stem cell (iPSC)-derived motor neurons and in HeLa cells treated with the toxic peptides. Bioinformatic studies support a specific role for U2-snRNP-dependent mis-splicing in C9ORF72 patient brains. Together, our data indicate that DPR-mediated dysfunction of U2 snRNP could account for as much as ∼44% of the mis-spliced cassette exons in C9ORF72 patient brains. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Sensitivity analysis of TRX-2 lattice parameters with emphasis on epithermal /sup 238/U capture. Final report

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

Tomlinson, E.T.; deSaussure, G.; Weisbin, C.R.

1977-03-01

The main purpose of the study is the determination of the sensitivity of TRX-2 thermal lattice performance parameters to nuclear cross section data, particularly the epithermal resonance capture cross section of /sup 238/U. An energy-dependent sensitivity profile was generated for each of the performance parameters, to the most important cross sections of the various isotopes in the lattice. Uncertainties in the calculated values of the performance parameters due to estimated uncertainties in the basic nuclear data, deduced in this study, were shown to be small compared to the uncertainties in the measured values of the performance parameter and compared tomore » differences among calculations based upon the same data but with different methodologies.« less

Improved mb-Ms Discrimination Using mb(P-coda) and MsU with Application to the Six North Korean Nuclear Tests

NASA Astrophysics Data System (ADS)

Napoli, V.; Yoo, S. H.; Russell, D. R.

2017-12-01

To improve discrimination of small explosions and earthquakes, we developed a new magnitude scale based on the standard Ms:mb discrimination method. In place of 20 second Ms measurements we developed a unified Rayleigh and Love wave magnitude scale (MsU) that is designed to maximize available information from single stations and then combine magnitude estimates into network averages. Additionally, in place of mb(P) measurements we developed an mb(P-Coda) magnitude scale as the properties of the coda make sparse network mb(P-Coda) more robust and less variable than network mb(P) estimates. A previous mb:MsU study conducted in 2013 in the Korean Peninsula shows that the use of MsU in place of standard 20 second Ms, leads to increased population separation and reduced scattering. The goals of a combined mb(P-coda):MsU scale are reducing scatter, ensuring applicability at small magnitudes with sparse networks, and improving the overall distribution for mb:Ms earthquake and explosion populations. To test this method we are calculating mb(P-coda)and MsU for a catalog earthquakes located in and near the Korean Peninsula, for the six North Korean nuclear tests (4.1 < mb < 6.3) and for the 3 aftershocks to date that occurred after the sixth test (2.6 < ML < 4.0). Compared to the previous 2013 study, we expect to see greater separation in the populations and less scattering with the inclusion of mb(P-coda) and with the implementation of additional filters for MsU to improve signal-to-noise levels; this includes S-transform filtering for polarization and off-azimuth signal reduction at regional distances. As we are expanding our database of mb(P-coda):MsU measurements in the Korean Peninsula to determine the earthquake and explosion distribution, this research will address the limitations and potential for discriminating small magnitude events using sparse networks.

Complementary DNA cloning, sequence analysis, and tissue transcription profile of a novel U2AF2 gene from the Chinese Banna mini-pig inbred line.

PubMed

Wang, S Y; Huo, J L; Miao, Y W; Cheng, W M; Zeng, Y Z

2013-04-02

U2 small nuclear RNA auxiliary factor 2 (U2AF2) is an important gene for pre-messenger RNA splicing in higher eukaryotes. In this study, the Banna mini-pig inbred line (BMI) U2AF2 coding sequence (CDS) was cloned, sequenced, and characterized. The U2AF2 complete CDS was amplified using the reverse transcription-polymerase chain reaction (RT-PCR) technique based on the conserved sequence information of cattle and known highly homologous swine expressed sequence tags. This novel gene was deposited into the National Center for Biotechnology Information database (Accession No. JQ839267). Sequence analysis revealed that the BMI U2AF2 coding sequence consisted of 1416 bp and encoded 471 amino acids with a molecular weight of 53.12 kDa. The protein sequence has high sequence homology with U2AF65 of 6 species - Homo sapiens (100%), Equus caballus (100%), Canis lupus (100%), Macaca mulatta (99.8%), Bos taurus (74.4%), and Mus musculus (74.4%). The phylogenetic tree analysis revealed that BMI U2AF65 has a closer genetic relationship with B. taurus U2AF65 than with U2AF65 of E. caballus, C. lupus, M. mulatta, H. sapiens, and M. musculus. RT-PCR analysis showed that BMI U2AF2 was most highly expressed in the brain; moderately expressed in the spleen, lung, muscle, and skin; and weakly expressed in the liver, kidney, and ovary. Its expression was nearly silent in the spinal cord, nerve fiber, heart, stomach, pancreas, and intestine. Three microRNA target sites were predicted in the CDS of BMI U2AF2 messenger RNA. Our results establish a foundation for further insight into this swine gene.

Examining the intersection between splicing, nuclear export and small RNA pathways.

PubMed

Nabih, Amena; Sobotka, Julia A; Wu, Monica Z; Wedeles, Christopher J; Claycomb, Julie M

2017-11-01

Nuclear Argonaute/small RNA pathways in a variety of eukaryotic species are generally known to regulate gene expression via chromatin modulation and transcription attenuation in a process known as transcriptional gene silencing (TGS). However, recent data, including genetic screens, phylogenetic profiling, and molecular mechanistic studies, also point to a novel and emerging intersection between the splicing and nuclear export machinery with nuclear Argonaute/small RNA pathways in many organisms. In this review, we summarize the field's current understanding regarding the relationship between splicing, export and small RNA pathways, and consider the biological implications for coordinated regulation of transcripts by these pathways. We also address the importance and available approaches for understanding the RNA regulatory logic generated by the intersection of these particular pathways in the context of synthetic biology. The interactions between various eukaryotic RNA regulatory pathways, particularly splicing, nuclear export and small RNA pathways provide a type of combinatorial code that informs the identity ("self" versus "non-self") and dictates the fate of each transcript in a cell. Although the molecular mechanisms for how splicing and nuclear export impact small RNA pathways are not entirely clear at this early stage, the links between these pathways are widespread across eukaryotic phyla. The link between splicing, nuclear export, and small RNA pathways is emerging and establishes a new frontier for understanding the combinatorial logic of gene regulation across species that could someday be harnessed for therapeutic, biotechnology and agricultural applications. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.

Nuclear Resonance Fluorescence Response of U-235

NASA Astrophysics Data System (ADS)

Warren, Glen

2008-05-01

Nuclear resonance fluorescence (NRF) is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample, which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. Pacific Northwest National Laboratory and Passport Systems have collaboratively conducted a set of measurements to search for an NRF response of U-235 in the 1.5 to 9 MeV energy range. Results from these measurements will be presented.

Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)

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

Bruce G. Schnitzler; Stanley K. Borowski

2010-07-01

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effortmore » was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature profiles in the engines. Engine performance can be improved by some combination of propellant flow control at the fuel element level and by varying the fuel composition. Enrichment zoning at the fuel element level with lower enrichments in the higher power elements at the core center and on the core periphery is particularly effective. Power flattening by enrichment zoning typically results in more uniform propellant exit temperatures and improved engine performance. For the SNRE, element enrichment zoning provided very flat radial power profiles with 551 of

Alteration of the SETBP1 gene and splicing pathway genes SF3B1, U2AF1, and SRSF2 in childhood acute myeloid leukemia.

PubMed

Choi, Hyun-Woo; Kim, Hye-Ran; Baek, Hee-Jo; Kook, Hoon; Cho, Duck; Shin, Jong-Hee; Suh, Soon-Pal; Ryang, Dong-Wook; Shin, Myung-Geun

2015-01-01

Recurrent somatic SET-binding protein 1 (SETBP1) and splicing pathway gene mutations have recently been found in atypical chronic myeloid leukemia and other hematologic malignancies. These mutations have been comprehensively analyzed in adult AML, but not in childhood AML. We investigated possible alteration of the SETBP1, splicing factor 3B subunit 1 (SF3B1), U2 small nuclear RNA auxiliary factor 1 (U2AF1), and serine/arginine-rich splicing factor 2 (SRSF2) genes in childhood AML. Cytogenetic and molecular analyses were performed to reveal chromosomal and genetic alterations. Sequence alterations in the SETBP1, SF3B1, U2AF1, and SRSF2 genes were examined by using direct sequencing in a cohort of 53 childhood AML patients. Childhood AML patients did not harbor any recurrent SETBP1 gene mutations, although our study did identify a synonymous mutation in one patient. None of the previously reported aberrations in the mutational hotspot of SF3B1, U2AF1, and SRSF2 were identified in any of the 53 patients. Alterations of the SETBP1 gene or SF3B1, U2AF1, and SRSF2 genes are not common genetic events in childhood AML, implying that the mutations are unlikely to exert a driver effect in myeloid leukemogenesis during childhood.

Uncertainty analysis on reactivity and discharged inventory for a pressurized water reactor fuel assembly due to {sup 235,238}U nuclear data uncertainties

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

Da Cruz, D. F.; Rochman, D.; Koning, A. J.

2012-07-01

This paper discusses the uncertainty analysis on reactivity and inventory for a typical PWR fuel element as a result of uncertainties in {sup 235,238}U nuclear data. A typical Westinghouse 3-loop fuel assembly fuelled with UO{sub 2} fuel with 4.8% enrichment has been selected. The Total Monte-Carlo method has been applied using the deterministic transport code DRAGON. This code allows the generation of the few-groups nuclear data libraries by directly using data contained in the nuclear data evaluation files. The nuclear data used in this study is from the JEFF3.1 evaluation, and the nuclear data files for {sup 238}U and {supmore » 235}U (randomized for the generation of the various DRAGON libraries) are taken from the nuclear data library TENDL. The total uncertainty (obtained by randomizing all {sup 238}U and {sup 235}U nuclear data in the ENDF files) on the reactor parameters has been split into different components (different nuclear reaction channels). Results show that the TMC method in combination with a deterministic transport code constitutes a powerful tool for performing uncertainty and sensitivity analysis of reactor physics parameters. (authors)« less

Economic and Market Challenges Facing the U.S. Nuclear Commercial Fleet

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

Szilard, Ronaldo; Sharpe, Phil; Kee, Edward

This report identifies underlying economic and electricity market factors that have led to early retirements of U.S. operating nuclear power plants, assesses the Gap between operating revenues and operating costs for selected nuclear power plants, and discusses a range of actions that might be taken to stop early retirement of operating nuclear power plants. The Kewaunee and Vermont Yankee nuclear power plants were retired early for economic and financial reasons. Early retirement has been announced or proposed for Clinton and Quad Cities in Illinois, Fitzpatrick and Ginna in New York, Fort Calhoun in Nebraska. Other nuclear power plants, including Palisades,more » Davis-Besse, Prairie Island, and Three Mile Island Unit 1, have been identified as facing financial stress that might lead to early retirement. The early retirement of operating nuclear power plants will mean the loss of a large amount of zero-emission electricity, inconsistent with the goal of reducing carbon emissions in the electricity sector. This report provides a high-level view of the major factors driving early retirement: • The U.S. market and private ownership approach to the electricity sector; • Low electricity market prices resulting from low natural gas prices, low demand growth, increased penetration of renewable generation, and negative electricity market prices; and • No compensation to nuclear power plants for public benefits including zero-emission electricity.« less

The crystal structure of ianthinite, [U 24+(UO 2) 4O 6(OH) 4(H 2O) 4](H 2O) 5: a possible phase for Pu 4+ incorporation during the oxidation of spent nuclear fuel

NASA Astrophysics Data System (ADS)

Burns, Peter C.; Finch, Robert J.; Hawthorne, Frank C.; Miller, Mark L.; Ewing, Rodney C.

1997-10-01

Ianthinite, [U 24+(UO 2) 4O 6(OH) 4(H 2O) 4](H 2O) 5, is the only known uranyl oxide hydrate mineral that contains U 4+, and it has been proposed that ianthinite may be an important Pu 4+-bearing phase during the oxidative dissolution of spent nuclear fuel. The crystal structure of ianthinite, orthorhombic, a = 0.7178(2), b = 1.1473(2), c = 3.039(1) nm, V = 2.5027 nm 3Z = 4, space group P2 1cn, has been solved by direct methods and refined by least-squares methods to an R index of 9.7% and a wR index of 12.6% using 888 unique observed [| F| ≥ 5 σ | F|] reflections. The structure contains both U 4+. The U 6+ cations are present as roughly linear (U 6+O 2) 2+ uranyl ion (Ur) that are in turn coordinated by five O 2- and OH - located at the equatorial positions of pentagonal bipyramids. The U 4+ cations are coordinated by O 2-, OH - and H 2O in a distorted octahedral arrangement. The Ur φ5and U 4+| 6 (φ: O 2-, OH -, H 2O) polyhedra l sharing edges to for two symmetrically distinct sheets at z ≈ 0.0 and z ≈ 0.25 that are parallel to (001). The sheets have the β-U 3O 8 sheet anion-topology. There are five symmetrically distinct H 2O groips located at z ≈ 0.125 between the sheets of U φn polyhedra, and the sheets of U φn polyhedra are linked together only by hydrogen bonding to the intersheet H 2O groups. The crystal-chemical requirements of U 4+ and Pu 4+ are very similar, suggesting that extensive Pu 4+ ↔ U 4+ substitution may occur within the sheets of U φn polyhedra in trh structure of ianthinine.

Nuclear EGFRvIII resists hypoxic microenvironment induced apoptosis via recruiting ERK1/2 nuclear translocation

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

Xie, Hui; Yang, Jinfeng; Xing, Wenjing

2016-02-05

Glioblastoma (GBM) is the most aggressive type of primary brain tumor. Its interaction with the tumor microenvironment promotes tumor progression. Furthermore, GBM bearing expression of EGFRvIII displays more adaptation to tumor microenvironment related stress. But the mechanisms were poorly understood. Here, we presented evidence that in the human U87MG glioblastoma tumor model, EGFRvIII overexpression led aberrant kinase activation and nuclear translocation of EGFRvIII/ERK1/2 under hypoxia, which induced growth advantage by resisting apoptosis. Additionally, EGFRvIII defective in nuclear entry impaired this capacity in hypoxia adaptation, and partially interrupted ERK1/2 nuclear translocation. Pharmacology or genetic interference ERK1/2 decreased hypoxia resistance triggered bymore » EGFRvIII expression, but not EGFRvIII nuclear translocation. In summary, this study identified a novel role for EGFRvIII in hypoxia tolerance, supporting an important link between hypoxia and subcellular localization alterations of the receptor. - Highlights: • Nuclear translocation of EGFRvIII contributes to GBM cell apoptotic resistance by hypoxia. • Nuclear ERK1/2 facilitates EGFRvIII in hypoxia resistance. • EGFRvIII nuclear translocation is not dependent on ERK1/2.« less

75 FR 11136 - Federal Advisory Committee; U.S. Nuclear Command and Control System Comprehensive Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-10

... DEPARTMENT OF DEFENSE Office of the Secretary Federal Advisory Committee; U.S. Nuclear Command and Control System Comprehensive Review Committee; Charter Termination AGENCY: Department of Defense (DoD... terminating the charter for the U.S. Nuclear Command and Control System Comprehensive Review Committee. FOR...

U.S. Strategic Nuclear Policy and Force Structure: Three Analytical Approaches

DTIC Science & Technology

1999-12-01

research rocket fired from Norway, an incident that sparked strong concerns that nuclear war 18 Lachlan Forrow, Bruce Blair, Ira Helfnad, George Lewis...quoted in R. Jeffrey Smith , "Clinton Directive Changes Strategy On Nuclear Arms," Washington Post, 7 December 1997, Al. 86 President William...Meyers, "U.S. Updates Nuclear War Guidelines," New York Times, 8 December 1997, 4. 233 Bell quoted in R. Jeffrey Smith , "Clinton Directive Changes

U.S. Nuclear Engineering Education: Status and Prospects.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC. Commission on Engineering and Technical Systems.

This study examines the status of and outlook for nuclear engineering (NE) in the United States. The study resulted from a concern about the downward trends in student enrollments in NE, in both graduate and undergraduate programs. Concerns have also been expressed about the declining number of U.S. university NE departments and programs, the…

U.S.-Russian cooperation in nuclear disarmament and nonproliferation

NASA Astrophysics Data System (ADS)

Podvig, Pavel

2010-02-01

The United States and Russia, the two largest nuclear powers, have a special obligation to provide leadership in nuclear disarmament and in strengthening the nuclear non-proliferation regime. In the past year the two countries made an effort to restart the arms control process by concluding a new treaty that would bring their legal disarmament obligations in line with the realities of their post-cold war relationships. The process of negotiating deeper nuclear reductions in the new environment turned out to be rather difficult, since the approaches that the countries used in the past are not well suited to dealing with issues like conversion of strategic nuclear delivery systems to conventional missions, tactical nuclear weapons, or dismantlement of nuclear warheads. This presentation considers the recent progress in U.S.-Russian arms control process and outlines the key issues at the negotiations. It also considers prospects for further progress in bilateral nuclear disarmament and issues that will be encountered at later stages of the process. The author argues that success of the arms reductions will depend on whether the United States and Russia will be able to build an institutional framework for cooperation on a range of issues - from traditional arms control to securing nuclear materials and from missile defense to strengthening the international nuclear safeguards. )

Assessing the impact of nuclear retirements on the U.S. power sector

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

Richards, James; Cole, Wesley J.

This work utilizes the Regional Energy Deployment System (ReEDS) model to analyze the impacts of four nuclear retirement scenarios of the U.S. electricity sector, from nuclear plant lifetimes of 50 to 80 years. The analysis finds that longer nuclear lifetimes decrease the amount of renewable and natural gas capacity. Longer nuclear lifetimes also resulted in lower cumulative and annual carbon emissions, lower transmission builds, and higher energy curtailment and water usage.

78 FR 9938 - U.S.-Korea Free Trade Agreement: Effects on U.S. Small and Medium-Sized Enterprises; Institution...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-12

... Trade Agreement on U.S. small and medium-sized enterprises (SMEs) since entry into force of the... effects of the agreement on the production, distribution, and export strategy of U.S. SMEs, as identified by those SMEs, and describing how U.S. SMEs have benefited from specific provisions of the agreement...

Usb1 controls U6 snRNP assembly through evolutionarily divergent cyclic phosphodiesterase activities.

PubMed

Didychuk, Allison L; Montemayor, Eric J; Carrocci, Tucker J; DeLaitsch, Andrew T; Lucarelli, Stefani E; Westler, William M; Brow, David A; Hoskins, Aaron A; Butcher, Samuel E

2017-09-08

U6 small nuclear ribonucleoprotein (snRNP) biogenesis is essential for spliceosome assembly, but not well understood. Here, we report structures of the U6 RNA processing enzyme Usb1 from yeast and a substrate analog bound complex from humans. Unlike the human ortholog, we show that yeast Usb1 has cyclic phosphodiesterase activity that leaves a terminal 3' phosphate which prevents overprocessing. Usb1 processing of U6 RNA dramatically alters its affinity for cognate RNA-binding proteins. We reconstitute the post-transcriptional assembly of yeast U6 snRNP in vitro, which occurs through a complex series of handoffs involving 10 proteins (Lhp1, Prp24, Usb1 and Lsm2-8) and anti-cooperative interactions between Prp24 and Lhp1. We propose a model for U6 snRNP assembly that explains how evolutionarily divergent and seemingly antagonistic proteins cooperate to protect and chaperone the nascent snRNA during its journey to the spliceosome.The mechanism of U6 small nuclear ribonucleoprotein (snRNP) biogenesis is not well understood. Here the authors characterize the enzymatic activities and structures of yeast and human U6 RNA processing enzyme Usb1, reconstitute post-transcriptional assembly of yeast U6 snRNP in vitro, and propose a model for U6 snRNP assembly.

Effect of Al(OH)3 on the sintering of UO2-Gd2O3 fuel pellets with addition of U3O8 from recycle

NASA Astrophysics Data System (ADS)

dos Santos, Lauro Roberto; Durazzo, Michelangelo; Urano de Carvalho, Elita Fontenele; Riella, Humberto Gracher

2017-09-01

The incorporation of gadolinium as burnable poison directly into nuclear fuel is important for reactivity compensation, which enables longer fuel cycles. The function of the burnable poison fuel is to control the neutron population in the reactor core during its startup and the beginning of the fuel burning cycle to extend the use of the fuel. The implementation of UO2-Gd2O3 poisoned fuel in Brazil has been proposed according to the future requirements established for the Angra-2 nuclear power plant. The UO2 powder used is produced from the Ammonium Uranyl Carbonate (AUC). The incorporation of Gd2O3 powder directly into the AUC-derived UO2 powder by dry mechanical blending is the most attractive process, because of its simplicity. Nevertheless, processing by this method leads to difficulties while obtaining sintered pellets with the minimum required density. The cause of the low densities is the bad sintering behavior of the UO2-Gd2O3 mixed fuel, which shows a blockage in the sintering process that hinders the densification. This effect has been overcome by microdoping of the fuel with small quantities of aluminum. The process for manufacturing the fuel inevitably generates uranium-rich scraps from various sources. This residue is reincorporated into the production process in the form of U3O8 powder additions. The addition of U3O8 also hinders densification in sintering. This study was carried out to investigate the influence of both aluminum and U3O8 additives on the density of fuel pellets after sintering. As the effects of these additives are counterposed, this work studied the combined effect thereof, seeking to find an applicable composition for the production process. The experimental results demonstrated the effectiveness of aluminum, in the form of Al(OH)3, as an additive to promote increase in the densification of the (U,Gd)O2 pellets during sintering, even with high additions of U3O8 recycled from the manufacturing process.

Tactical Nuclear Weapons-Does the U.S. Army Still Need Them?

DTIC Science & Technology

1995-05-17

Harry Summers, Colonel, US Army (Ret), "Good Riddance to a Nuclear Disaster ," Army Times, October 14, 1991, p. 78. 140 MAJ Vokac, p. 24. 141 Biddle, p...Role in U.S. Military Strategy?" Comparative Strategy, Vol. 13, pp. 197-209. Summers, Harry, Col. US Army (Ret), "Good Riddance to Nuclear Disaster ," Army

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.

Benchmarking U.S. Small Wind Costs with the Distributed Wind Taxonomy

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

Orrell, Alice C.; Poehlman, Eric A.

The objective of this report is to benchmark costs for small wind projects installed in the United States using a distributed wind taxonomy. Consequently, this report is a starting point to help expand the U.S. distributed wind market by informing potential areas for small wind cost-reduction opportunities and providing a benchmark to track future small wind cost-reduction progress.

Optimization of small long-life PWR based on thorium fuel

NASA Astrophysics Data System (ADS)

Subkhi, Moh Nurul; Suud, Zaki; Waris, Abdul; Permana, Sidik

2015-09-01

A conceptual design of small long-life Pressurized Water Reactor (PWR) using thorium fuel has been investigated in neutronic aspect. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.2, while the multi-energy-group diffusion calculations were optimized in three-dimension X-Y-Z geometry of core by COREBN. The excess reactivity of thorium nitride with ZIRLO cladding is considered during 5 years of burnup without refueling. Optimization of 350 MWe long life PWR based on 5% 233U & 2.8% 231Pa, 6% 233U & 2.8% 231Pa and 7% 233U & 6% 231Pa give low excess reactivity.

76 FR 3678 - Board Meeting: February 16, 2011-Las Vegas, NV, the U.S. Nuclear Waste Technical Review Board...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-20

... NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Meeting: February 16, 2011--Las Vegas, NV, the U.S. Nuclear Waste Technical Review Board Will Meet To Discuss DOE Activities Related to Managing Spent Nuclear...-203, Nuclear Waste Policy Amendments Act of 1987, the U.S. Nuclear Waste Technical Review Board will...

Application of ex situ dynamic nuclear polarization in studying small molecules.

PubMed

Ludwig, Christian; Marin-Montesinos, Ildefonso; Saunders, Martin G; Emwas, Abdul-Hamid; Pikramenou, Zoe; Hammond, Stephen P; Günther, Ulrich L

2010-06-14

Dynamic nuclear polarization (DNP) has become an attractive technique to boost the sensitivity of NMR experiments. In the case of ex situ polarizations two-dimensional (2D) spectra are limited by the short lifetime of the polarization after dissolution and sample transfer to a high field NMR magnet. This limitation can be overcome by various approaches. Here we show how the use of (13)C-labelled acetyl tags can help to obtain 2D-HMQC spectra for many small molecules, owing to a nuclear Overhauser enhancement between (13)C spins originating from the long-lived carbonyl carbon, which extends the lifetimes of other (13)C spins with shorter longitudinal relaxation times. We also show an alternative approach of using an optimized polarization matrix.

77 FR 55509 - Indiana Michigan Power Company; Donald C. Cook Nuclear Plant, Unit 2; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-10

...; Donald C. Cook Nuclear Plant, Unit 2; Exemption 1.0 Background Indian Michigan Power Company (the... Donald C. Cook Nuclear Plant, Unit 2 (CNP-2). The license provides, among other things, that the facility is subject to all rules, regulations, and orders of the U.S Nuclear Regulatory Commission (NRC, or...

U.S./CIS eye joint nuclear rocket venture

NASA Technical Reports Server (NTRS)

Clark, John S.; Mcilwain, Melvin C.; Smetanikov, Vladimir; D'Yakov, Evgenij K.; Pavshuk, Vladimir A.

1993-01-01

An account is given of the significance for U.S. spacecraft development of a nuclear thermal rocket (NTR) reactor concept that has been developed in the (formerly Soviet) Commonwealth of Independent States (CIS). The CIS NTR reactor employs a hydrogen-cooled zirconium hydride moderator and ternary carbide fuels; the comparatively cool operating temperatures associated with this design promise overall robustness.

Thinking Globally about U.S. Extended Deterrence

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

Roberts, Brad; Santoro, David; Volpe, Tristan

In contrast to the Cold War bilateral global competition between the United States and the Soviet Union, the modern nuclear age features a more complex, multiplayer arena on the regional scale. With the exception of the U.S. and Russia, most major powers retain relatively small nuclear arsenals or technical hedge capabilities. The U.S., with strong interests and security partnerships in Europe, Northeast Asia, and the Middle East, must navigate through long-standing rivalries and active conflicts while attempting to divine the intentions of less experienced nuclear decision makers in charge of weak domestic institutions. As a result, analysts and policymakers mustmore » think globally about U.S. extended deterrence. How have the requirements of extended deterrence and assurance changed? Are there important threads that connect each region? What should the U.S. do differently? To explore these questions, Lawrence Livermore National Laboratory’s Center for Global Security Research, in partnership with the Carnegie Endowment for International Peace and the Pacific Forum CSIS, held a workshop on “Thinking Globally about U.S. Extended Deterrence” in Washington, DC on November 2, 2015. The workshop brought together approximately 40 U.S. and foreign deterrence specialists and government officials, all attending in their private capacities. The participants joined a day of not-for-attribution discussions on the changing deterrence and assurance requirements, the threads that connect the regions, and U.S. strategy to deal with emerging challenges. The following is a summary of key takeaways.« less

Drosophila SMN complex proteins Gemin2, Gemin3, and Gemin5 are components of U bodies

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

Cauchi, Ruben J.; Sanchez-Pulido, Luis; Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk

2010-08-15

Uridine-rich small nuclear ribonucleoproteins (U snRNPs) play key roles in pre-mRNA processing in the nucleus. The assembly of most U snRNPs takes place in the cytoplasm and is facilitated by the survival motor neuron (SMN) complex. Discrete cytoplasmic RNA granules called U bodies have been proposed to be specific sites for snRNP assembly because they contain U snRNPs and SMN. U bodies invariably associate with P bodies, which are involved in mRNA decay and translational control. However, it remains unknown whether other SMN complex proteins also localise to U bodies. In Drosophila there are four SMN complex proteins, namely SMN,more » Gemin2/CG10419, Gemin3 and Gemin5/Rigor mortis. Drosophila Gemin3 was originally identified as the Drosophila orthologue of human and yeast Dhh1, a component of P bodies. Through an in silico analysis of the DEAD-box RNA helicases we confirmed that Gemin3 is the bona fide Drosophila orthologue of vertebrate Gemin3 whereas the Drosophila orthologue of Dhh1 is Me31B. We then made use of the Drosophila egg chamber as a model system to study the subcellular distribution of the Gemin proteins as well as Me31B. Our cytological investigations show that Gemin2, Gemin3 and Gemin5 colocalise with SMN in U bodies. Although they are excluded from P bodies, as components of U bodies, Gemin2, Gemin3 and Gemin5 are consistently found associated with P bodies, wherein Me31B resides. In addition to a role in snRNP biogenesis, SMN complexes residing in U bodies may also be involved in mRNP assembly and/or transport.« less

NIMBY, CLAMP, and the location of new nuclear-related facilities: U.S. national and 11 site-specific surveys.

PubMed

Greenberg, Michael R

2009-09-01

Public and political opposition have made finding locations for new nuclear power plants, waste management, and nuclear research and development facilities a challenge for the U.S. government and the nuclear industry. U.S. government-owned properties that already have nuclear-related activities and commercial nuclear power generating stations are logical locations. Several studies and utility applications to the Nuclear Regulatory Commission suggest that concentrating locations at major plants (CLAMP) has become an implicit siting policy. We surveyed 2,101 people who lived within 50 miles of 11 existing major nuclear sites and 600 who lived elsewhere in the United States. Thirty-four percent favored CLAMP for new nuclear power plants, 52% for waste management facilities, and 50% for new nuclear laboratories. College educated, relatively affluent male whites were the strongest CLAMP supporters. They disproportionately trusted those responsible for the facilities and were not worried about existing nuclear facilities or other local environmental issues. Notably, they were concerned about continuing coal use. Not surprisingly, CLAMP proponents tended to be familiar with their existing local nuclear site. In short, likely CLAMP sites have a large and politically powerful core group to support a CLAMP policy. The challenge to proponents of nuclear technologies will be to sustain this support and expand the base among those who clearly are less connected and receptive to new nearby sites.

Precise 238U(n,2n)237U reaction cross-section measurements using the activation facility at TUNL

NASA Astrophysics Data System (ADS)

Krishichayan, Fnu; Bhike, M.; Tornow, W.

2014-09-01

Accurate neutron-induced 238U(n,2n)237U reaction data are required for many practical applications, especially in the field of nuclear energy, including advanced heavy water reactors, where 238U is used as the breeding material to regenerate the fissile material 239Pu. Precise (n,2n) cross-section measurements of 238U are underway at TUNL with mono-energetic neutrons in the 8.0 to 14.0 MeV energy range in steps of 0.25 MeV using the activation technique. After activation of the 0.5 inch diameter and 442 mg 238U foil, the activity of the 208 keV characteristic γ-line is tracked for 6 weeks with a high efficient HPGe clover detector to determine the initial activity needed for the cross-section determination. Results of the cross-section measurements, determined relative to 27Al and 197Au neutron activation monitor foils, and the comparison with theoretical models will be presented during the meeting.

Escherichia coli tRNA 2-selenouridine synthase (SelU) converts S2U-RNA to Se2U-RNA via S-geranylated-intermediate.

PubMed

Sierant, Malgorzata; Leszczynska, Grazyna; Sadowska, Klaudia; Komar, Patrycja; Radzikowska-Cieciura, Ewa; Sochacka, Elzbieta; Nawrot, Barbara

2018-06-04

To date the only tRNAs containing nucleosides modified with a selenium (5-carboxymethylaminomethyl-2-selenouridine and 5-methylaminomethyl-2-selenouridine) have been found in bacteria. By using tRNA anticodon-stem-loop fragments containing S2U, Se2U, or geS2U, we found that in vitro tRNA 2-selenouridine synthase (SelU) converts S2U-RNA to Se2U-RNA in a two-step process involving S2U-RNA geranylation (with ppGe) and subsequent selenation of the resulting geS2U-RNA (with SePO 3 3- ). No 'direct' S2U-RNA→Se2U-RNA replacement is observed in the presence of SelU/SePO 3 3- only (without ppGe). These results suggest that the in vivo S2U→Se2U and S2U→geS2U transformations in tRNA, so far claimed to be the elementary reactions occurring independently in the same domain of the SelU enzyme, should be considered a combination of two consecutive events - geranylation (S2U→geS2U) and selenation (geS2U→Se2U). © 2018 Federation of European Biochemical Societies.

Old foes, new understandings: nuclear entry of small non-enveloped DNA viruses.

PubMed

Fay, Nikta; Panté, Nelly

2015-06-01

The nuclear import of viral genomes is an important step of the infectious cycle for viruses that replicate in the nucleus of their host cells. Although most viruses use the cellular nuclear import machinery or some components of this machinery, others have developed sophisticated ways to reach the nucleus. Some of these have been known for some time; however, recent studies have changed our understanding of how some non-enveloped DNA viruses access the nucleus. For example, parvoviruses enter the nucleus through small disruptions of the nuclear membranes and nuclear lamina, and adenovirus tugs at the nuclear pore complex, using kinesin-1, to disassemble their capsids and deliver viral proteins and genomes into the nucleus. Here we review recent findings of the nuclear import strategies of three small non-enveloped DNA viruses, including adenovirus, parvovirus, and the polyomavirus simian virus 40. Copyright © 2015 Elsevier B.V. All rights reserved.

Small molecule antagonists of the urokinase (uPA): urokinase receptor (uPAR) interaction with high reported potencies show only weak effects in cell-based competition assays employing the native uPAR ligand.

PubMed

De Souza, Melissa; Matthews, Hayden; Lee, Jodi A; Ranson, Marie; Kelso, Michael J

2011-04-15

Binding of the urokinase-type plasminogen activator (uPA) to its cell-surface-bound receptor uPAR and upregulation of the plasminogen activation system (PAS) correlates with increased metastasis and poor prognosis in several tumour types. Disruptors of the uPA:uPAR interaction represent promising anti-tumour/metastasis agents and several approaches have been explored for this purpose, including the use of small molecule antagonists. Two highly potent non-peptidic antagonists 1 and 2 (IC(50)1=0.8 nM, IC(50)2=33 nM) from the patent literature were reportedly identified using competition assays employing radiolabelled uPAR-binding uPA fragments and appeared as useful pharmacological tools for studying the PAS. Before proceeding to such studies, confirmation was sought that 1 and 2 retained their potencies in physiologically relevant cell-based competition assays employing uPAR's native binding partner high molecular weight uPA (HMW-uPA). This study describes a new solution phase synthesis of 1, a mixed solid/solution phase synthesis of 2 and reports the activities of 1 and 2 in semi-quantitative competition flow cytometry assays and quantitative cell-based uPA activity assays that employed HMW-uPA as the competing ligand. The flow cytometry experiments revealed that high concentrations of 2 (10-100 μM) are required to compete with HMW-uPA for uPAR binding and that 1 shows no antagonist effects at 100 μM. The cell-based enzyme activity assays similarly revealed that 1 and 2 are poor inhibitors of cell surface-bound HMW-uPA activity (IC(50) >100 μM for 1 and 2). The report highlights the dangers of identifying false-positive lead uPAR antagonists from competition assays employing labelled competing ligands other than the native HMW-uPA. Copyright © 2011 Elsevier Ltd. All rights reserved.

U.S. Nuclear Weapons Modernization - the Stockpile Life Extension Program

NASA Astrophysics Data System (ADS)

Cook, Donald

2016-03-01

Underground nuclear testing of U.S. nuclear weapons was halted by President George H.W. Bush in 1992 when he announced a moratorium. In 1993, the moratorium was extended by President Bill Clinton and, in 1995, a program of Stockpile Stewardship was put in its place. In 1996, President Clinton signed the Comprehensive Nuclear Test Ban Treaty (CTBT). Twenty years have passed since then. Over the same time, the average age of a nuclear weapon in the stockpile has increased from 6 years (1992) to nearly 29 years (2015). At its inception, achievement of the objectives of the Stockpile Stewardship Program (SSP) appeared possible but very difficult. The cost to design and construct several large facilities for precision experimentation in hydrodynamics and high energy density physics was large. The practical steps needed to move from computational platforms of less than 100 Mflops/sec to 10 Teraflops/sec and beyond were unknown. Today, most of the required facilities for SSP are in place and computational speed has been increased by more than six orders of magnitude. These, and the physicists and engineers in the complex of labs and plants within the National Nuclear Security Administration (NNSA) who put them in place, have been the basis for underpinning an annual decision, made by the weapons lab directors for each of the past 20 years, that resort to underground nuclear testing is not needed for maintaining confidence in the safety and reliability of the U.S stockpile. A key part of that decision has been annual assessment of the physical changes in stockpiled weapons. These weapons, quite simply, are systems that invariably and unstoppably age in the internal weapon environment of radioactive materials and complex interfaces of highly dissimilar organic and inorganic materials. Without an ongoing program to rebuild some components and replace other components to increase safety or security, i.e., life extending these weapons, either underground testing would again be

Cell lines that support replication of a novel herpes simplex virus 1 U{sub L}31 deletion mutant can properly target U{sub L}34 protein to the nuclear rim in the absence of U{sub L}31

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

Liang Li; Tanaka, Michiko; Kawaguchi, Yasushi

2004-11-10

Previous results indicated that the herpes simplex virus 1 (HSV-1) U{sub L}31 gene is necessary and sufficient for localization of the U{sub L}34 protein exclusively to the nuclear membrane of infected Hep2 cells. In the current studies, a bacterial artificial chromosome containing the entire HSV-1 strain F genome was used to construct a recombinant viral genome in which a gene encoding kanamycin resistance was inserted in place of 262 codons of the 306 codon U{sub L}31 open reading frame. The deletion virus produced virus titers approximately 10- to 50-fold lower in rabbit skin cells, more than 2000-fold lower in Veromore » cells, and more than 1500-fold lower in CV1 cells, compared to a virus bearing a restored U{sub L}31 gene. The replication of the U{sub L}31 deletion virus was restored on U{sub L}31-complementing cell lines derived either from rabbit skin cells or CV1 cells. Confocal microscopy indicated that the majority of U{sub L}34 protein localized aberrantly in the cytoplasm and nucleoplasm of Vero cells and CV1 cells, whereas U{sub L}34 protein localized at the nuclear membrane in rabbit skin cells, and U{sub L}31 complementing CV1 cells infected with the U{sub L}31 deletion virus. We conclude that rabbit skin cells encode a function that allows proper localization of U{sub L}34 protein to the nuclear membrane. We speculate that this function partially complements that of U{sub L}31 and may explain why U{sub L}31 is less critical for replication in rabbit skin cells as opposed to Vero and CV1 cells.« less

Thermophysical properties of U 3 Si 2 to 1773K

DOE PAGES

White, Joshua Taylor; Nelson, Andrew Thomas; Dunwoody, John Tyler; ...

2015-05-08

Use of U 3Si 2 in nuclear reactors requires accurate thermophysical property data to capture heat transfer within the core. Compilation of the limited previous research efforts focused on the most critical property, thermal conductivity, reveals extensive disagreement. Assessment of this data is challenged by the fact that the critical structural and chemical details of the material used to provide historic data is either absent or confirms the presence of significant impurity phases. This study was initiated to fabricate high purity U 3Si 2 to quantify the coefficient of thermal expansion, heat capacity, thermal diffusivity, and thermal conductivity from roommore » temperature to 1773 K. Here, the datasets provided in this manuscript will facilitate more detailed fuel performance modeling to assess both current and proposed reactor designs that incorporate U 3Si 2.« less

76 FR 24065 - Board Workshop: June 6-7, 2011-Arlington, Virginia; the U.S. Nuclear Waste Technical Review Board...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Workshop: June 6-7, 2011--Arlington, Virginia; the U.S. Nuclear Waste Technical Review Board Will Hold a Workshop on Methods for Evaluating Nuclear Waste Streams... 1987, the U.S. Nuclear Waste Technical Review Board will hold a workshop on Monday, June 6, and Tuesday...

A HUMAN FACTORS META MODEL FOR U.S. NUCLEAR POWER PLANT CONTROL ROOM MODERNIZATION

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

Joe, Jeffrey C.

Over the last several years, the United States (U.S.) Department of Energy (DOE) has sponsored human factors research and development (R&D) and human factors engineering (HFE) activities through its Light Water Reactor Sustainability (LWRS) program to modernize the main control rooms (MCR) of commercial nuclear power plants (NPP). Idaho National Laboratory (INL), in partnership with numerous commercial nuclear utilities, has conducted some of this R&D to enable the life extension of NPPs (i.e., provide the technical basis for the long-term reliability, productivity, safety, and security of U.S. NPPs). From these activities performed to date, a human factors meta model formore » U.S. NPP control room modernization can now be formulated. This paper discusses this emergent HFE meta model for NPP control room modernization, with the goal of providing an integrated high level roadmap and guidance on how to perform human factors R&D and HFE for those in the U.S. nuclear industry that are engaging in the process of upgrading their MCRs.« less

Measurement of 235U(n,n'γ) and 235U(n,2nγ) reaction cross sections

NASA Astrophysics Data System (ADS)

Kerveno, M.; Thiry, J. C.; Bacquias, A.; Borcea, C.; Dessagne, P.; Drohé, J. C.; Goriely, S.; Hilaire, S.; Jericha, E.; Karam, H.; Negret, A.; Pavlik, A.; Plompen, A. J. M.; Romain, P.; Rouki, C.; Rudolf, G.; Stanoiu, M.

2013-02-01

The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on (n,xnγ) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the 235U(n,n'γ) and 235U(n,2nγ) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and (n,2n) reactions] are identified by on-line prompt γ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

Optimization of small long-life PWR based on thorium fuel

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

Subkhi, Moh Nurul, E-mail: nsubkhi@students.itb.ac.id; Physics Dept., Faculty of Science and Technology, State Islamic University of Sunan Gunung Djati Bandung Jalan A.H Nasution 105 Bandung; Suud, Zaki, E-mail: szaki@fi.itb.ac.id

2015-09-30

A conceptual design of small long-life Pressurized Water Reactor (PWR) using thorium fuel has been investigated in neutronic aspect. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.2, while the multi-energy-group diffusion calculations were optimized in three-dimension X-Y-Z geometry of core by COREBN. The excess reactivity of thorium nitride with ZIRLO cladding is considered during 5 years of burnup without refueling. Optimization of 350 MWe long life PWR based on 5% {sup 233}U & 2.8% {sup 231}Pa, 6% {sup 233}U & 2.8% {sup 231}Pa and 7% {sup 233}U & 6% {supmore » 231}Pa give low excess reactivity.« less

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

NASA Technical Reports Server (NTRS)

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

1972-01-01

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

Atomic Mass and Nuclear Binding Energy for U-287 (Uranium)

NASA Astrophysics Data System (ADS)

Sukhoruchkin, S. I.; Soroko, Z. N.

This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope U-287 (Uranium, atomic number Z = 92, mass number A = 287).

Synthesis of phase-pure U 2N 3 microspheres and its decomposition into UN

DOE PAGES

Silva, Chinthaka M.; Hunt, Rodney Dale; Snead, Lance Lewis; ...

2014-12-12

Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. But, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U 2N 3) were synthesized by nitridation of UO 2+C microspheres at a few different temperatures.more » Resulting microspheres were of low-density U 2N 3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U 2N 3. Average grain sizes of both U 2N 3 and UN varied in a range of 1–2.5 μm. In addition, these had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.« less

Nuclear Resonance Fluorescence of U-235 above 3 MeV

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

Warren, Glen A.; Caggiano, Joseph A.; Miller, Erin A.

Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct measurements to search for a nuclear resonance fluorescence response of U-235 from 3 to 5 MeV using an 8 g sample of highly enriched uranium. These new measurements complement previously reported measurements below 3 MeV. Preliminary analysis indicates that no strong resonances exist for U-235 in this energy range. A second set of measurements focused on a signature search in the 5 to 10 MeV range is still under analysis.

Reviews of the Comprehensive Nuclear-Test-Ban Treaty and U.S. security

NASA Astrophysics Data System (ADS)

Jeanloz, Raymond

2017-11-01

Reviews of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) by the National Academy of Sciences concluded that the United States has the technical expertise and physical means to i) maintain a safe, secure and reliable nuclear-weapons stockpile without nuclear-explosion testing, and ii) effectively monitor global compliance once the Treaty enters into force. Moreover, the CTBT is judged to help constrain proliferation of nuclear-weapons technology, so it is considered favorable to U.S. security. Review of developments since the studies were published, in 2002 and 2012, show that the study conclusions remain valid and that technical capabilities are better than anticipated.

Investigations of systems ThO 2-MO 2-P 2O 5 (M=U, Ce, Zr, Pu). Solid solutions of thorium-uranium (IV) and thorium-plutonium (IV) phosphate-diphosphates

NASA Astrophysics Data System (ADS)

Dacheux, N.; Podor, R.; Brandel, V.; Genet, M.

1998-02-01

In the framework of nuclear waste management aiming at the research of a storage matrix, the chemistry of thorium phosphates has been completely re-examined. In the ThO 2-P 2O 5 system a new compound thorium phosphate-diphosphate Th 4(PO 4) 4P 2O 7 has been synthesized. The replacement of Th 4+ by a smaller cation like U 4+ and Pu 4+ in the thorium phosphate-diphosphate (TPD) lattice has been achieved. Th 4- xU x(PO 4) 4P 2O 7 and Th 4- xPu x(PO 4) 4P 2O 7 solid solutions have been synthesized through wet and dry processes with 0< x<3.0 for uranium and 0< x<1.0 for plutonium. From the variation of the unit cell parameters, an upper x value equal to 1.67 has been estimated for the thorium-plutonium (IV) phosphate-diphosphate solid solutions. Two other tetravalent cations, Ce 4+ and Zr 4+, cannot be incorporated in the TPD lattice: cerium (IV) because of its reduction into Ce (III) at high temperature, and zirconium probably because of its too small radius compared to thorium.

Revisiting the diffusion mechanism of helium in UO2: A DFT+U study

NASA Astrophysics Data System (ADS)

Liu, X.-Y.; Andersson, D. A.

2018-01-01

The understanding of migration properties of helium atoms after their generation through α-decay of actinides in spent nuclear fuels is important for the safety of nuclear fuel storage and disposal. The diffusion of helium in UO2 is revisited by using the DFT+U simulation methodology employing the "U-ramping" method to address the issue of metastable energy states. A novel diffusion mechanism by helium interstitials, the "asymmetric hop" mechanism, is reported and compared to other diffusion mechanisms including an oxygen vacancy mediated mechanism and available experimental diffusion data. The new mechanism is shown to be the dominant one over a wide temperature range.

Photofission cross-section ratio measurement of 235 U/ 238 U using monoenergetic photons in the energy range of 9.0–16.6 MeV

DOE PAGES

Krishichayan,; Bhike, Megha; Finch, S. W.; ...

2017-05-01

Photofission cross-section ratios of 235U and 238U have been measured using monoenergetic photon beams from the High Intensity Gamma-ray Source facility at the Triangle Universities Nuclear Laboratory. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. The measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

77 FR 39385 - Receipts-Based, Small Business Size Standard

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-03

... Business Size Standard AGENCY: Nuclear Regulatory Commission. ACTION: Direct final rule. SUMMARY: The U.S.... The NRC is increasing its receipts-based, small business size standard from $6.5 million to $7 million to conform to the standard set by the Small Business Administration (SBA). This size standard...

Effect of High Si Content on U3Si2 Fuel Microstructure

NASA Astrophysics Data System (ADS)

Rosales, Jhonathan; van Rooyen, Isabella J.; Meher, Subhashish; Hoggan, Rita; Parga, Clemente; Harp, Jason

2018-02-01

The development of U3Si2 as an accident-tolerant nuclear fuel has gained research interest because of its promising high uranium density and improved thermal properties. In the present study, three samples of U3Si2 fuel with varying silicon content have been fabricated by a conventional powder metallurgical route. Microstructural characterization via scanning and transmission electron microscopy reveals the presence of other stoichiometry of uranium silicide such as USi and UO2 in both samples. The detailed phase analysis by x-ray diffraction shows the presence of secondary phases, such as USi, U3Si, and UO2. The samples with higher concentrations of silicon content of 7.5 wt.% display additional elemental Si. These samples also possess an increased amount of the USi phase as compared to that in the conventional sample with 7.3 wt.% silicon. The optimization of U3Si2 fuel performance through the understanding of the role of Si content on its microstructure has been discussed.

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

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

Pacold, J. I.; Lukens, W. W.; Booth, C. H.

Nuclear weapons testing generates large volumes of glassy materials that influence the transport of dispersed actinides in the environment and may carry information on the composition of the detonated device. We determine the oxidation state of U and Fe (which is known to buffer the oxidation state of actinide elements and to affect the redox state of groundwater) in samples of melt glass collected from three U.S. nuclear weapons tests. For selected samples, we also determine the coordination geometry of U and Fe, and we report the oxidation state of Pu from one melt glass sample. We find significant variationsmore » among the melt glass samples and, in particular, find a clear deviation in one sample from the expected buffering effect of Fe(II)/Fe(III) on the oxidation state of uranium. In the first direct measurement of Pu oxidation state in a nuclear test melt glass, we obtain a result consistent with existing literature that proposes Pu is primarily present as Pu(IV) in post-detonation material. In addition, our measurements imply that highly mobile U(VI) may be produced in significant quantities when melt glass is quenched rapidly following a nuclear detonation, though these products may remain immobile in the vitrified matrices. The observed differences in chemical state among the three samples show that redox conditions can vary dramatically across different nuclear test conditions. The local soil composition, associated device materials, and the rate of quenching are all likely to affect the final redox state of the glass. The resulting variations in glass chemistry are significant for understanding and interpreting debris chemistry and the later environmental mobility of dispersed material.« less

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

NASA Astrophysics Data System (ADS)

Pacold, J. I.; Lukens, W. W.; Booth, C. H.; Shuh, D. K.; Knight, K. B.; Eppich, G. R.; Holliday, K. S.

2016-05-01

Nuclear weapons testing generates large volumes of glassy materials that influence the transport of dispersed actinides in the environment and may carry information on the composition of the detonated device. We determine the oxidation state of U and Fe (which is known to buffer the oxidation state of actinide elements and to affect the redox state of groundwater) in samples of melt glass collected from three U.S. nuclear weapons tests. For selected samples, we also determine the coordination geometry of U and Fe, and we report the oxidation state of Pu from one melt glass sample. We find significant variations among the melt glass samples and, in particular, find a clear deviation in one sample from the expected buffering effect of Fe(II)/Fe(III) on the oxidation state of uranium. In the first direct measurement of Pu oxidation state in a nuclear test melt glass, we obtain a result consistent with existing literature that proposes Pu is primarily present as Pu(IV) in post-detonation material. In addition, our measurements imply that highly mobile U(VI) may be produced in significant quantities when melt glass is quenched rapidly following a nuclear detonation, though these products may remain immobile in the vitrified matrices. The observed differences in chemical state among the three samples show that redox conditions can vary dramatically across different nuclear test conditions. The local soil composition, associated device materials, and the rate of quenching are all likely to affect the final redox state of the glass. The resulting variations in glass chemistry are significant for understanding and interpreting debris chemistry and the later environmental mobility of dispersed material.

U14 small nucleolar RNA makes multiple contacts with the pre-ribosomal RNA.

PubMed

Morrissey, J P; Tollervey, D

1997-06-01

The small nucleolar RNA (snoRNA) U14 has two regions of extended primary sequence complementarity to the 18S rRNA. The 3' region (domain B) shows the consensus structure for the methylation guide class of snoRNAs, whereas base-pairing between the 5' region (domain A) and the 18S rRNA sequence is required for the formation of functional ribosomes. Between domains A and B lies another essential region (domain Y). Here we report that yeast U14 can be cross-linked in vivo to the pre-rRNA; cross-linking is detected exclusively with the 35S primary transcript. Many nucleotides in U14 that lie outside of domains A and B are cross-linked to the pre-rRNA; in particular the essential domain Y region is cross-linked at several sites. U14 is, therefore, in far more extensive contact with the pre-rRNA than predicted from simple base-pairing models. Moreover, U14 can be cross-linked to other small RNA species. The functional interactions made by U14 during ribosome synthesis are likely to be very complex.

Heavy-ion irradiation effects on U3O8 incorporated Gd2Zr2O7 waste forms.

PubMed

Lu, Xirui; Shu, Xiaoyan; Chen, Shunzhang; Zhang, Kuibao; Chi, Fangtin; Zhang, Haibin; Shao, Dadong; Mao, Xueli

2018-06-12

In this research, the heavy-ion irradiation effects of U-bearing Gd 2 Zr 2 O 7 ceramics were explored for nuclear waste immobilization. U 3 O 8 was designed to be incorporated into Gd 2 Zr 2 O 7 from two different routes in the form of (Gd 1-4 x U 2 x ) 2 (Zr 1- x U x ) 2 O 7 (x = 0.1, 0.14). The self-irradiation of actinide nuclides was simulated by Xe 20+ heavy-ion radiation under different fluences. Grazing incidence X-ray diffraction (GIXRD) analysis reveals the relationship between radiation dose, damage and depth. The radiation tolerance is promoted with the increment of U 3 O 8 content in the discussed range. Raman spectroscopy testifies the enhancement of radiation tolerance and microscopically existed phase evolution from the chemical bond vibrations. In addition, the microstructure and elemental distribution of the irradiated samples were analyzed as well. The amorphization degree of the sample surface declines as the U content was elevated from x = 0.1 to x = 0.14. Copyright © 2018 Elsevier B.V. All rights reserved.

Study on underclad cracking in nuclear reactor vessel steels

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

Horiya, T.; Takeda, T.; Yamato, K.

1985-02-01

Susceptibility to underclad cracking in nuclear reactor vessel steels, such as SA533 Grade B Class 1 and SA508 Class 2, was studied in detail. A convenient simulation test method using simulated HAZ specimens of small size has been developed for quantitative evaluation of susceptibility to underclad cracks. The method can predict precisely the cracking behavior in weldments of steels with relative low crack susceptibility. The effect of chemical compositions on susceptibility to the cracking was examined systematically using the developed simulation test method and the following index was obtained from the test results: U = 20(V) + 7(C) + 4(Mo)more » + (Cr) + (Cu) - 0.5(Mn) + 1.5 log(X) X = Al . . . Al/2N less than or equal to 1 X = 2N . . . Al/2N > 1 It was confirmed that the new index (U) is useful for the prediction of crack susceptibility of the nuclear vessel steels; i.e., no crack initiation is detected in weldments in the roller bend test for steels having U value below 0.90.« less

U.S. Nuclear Regulatory Commission natural analogue research program

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

Kovach, L.A.; Ott, W.R.

1995-09-01

This article describes the natural analogue research program of the U.S. Nuclear Regulatory Commission (US NRC). It contains information on the regulatory context and organizational structure of the high-level radioactive waste research program plan. It also includes information on the conditions and processes constraining selection of natural analogues, describes initiatives of the US NRC, and describes the role of analogues in the licensing process.

Revisiting the diffusion mechanism of helium in UO 2 : A DFT+ U study

DOE PAGES

Liu, X. -Y.; Andersson, D. A.

2017-11-03

The understanding of migration properties of helium atoms after their generation through α-decay of actinides in spent nuclear fuels is important for the safety of nuclear fuel storage and disposal. The diffusion of helium in UO 2 is revisited by using the DFT+U simulation methodology employing the “U-ramping” method to address the issue of metastable energy states. A novel diffusion mechanism by helium interstitials, the “asymmetric hop” mechanism, is reported and compared to other diffusion mechanisms including an oxygen vacancy mediated mechanism and available experimental diffusion data. We show that the new mechanism is the dominant one over a widemore » temperature range.« less

Revisiting the diffusion mechanism of helium in UO 2 : A DFT+ U study

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

Liu, X. -Y.; Andersson, D. A.

The understanding of migration properties of helium atoms after their generation through α-decay of actinides in spent nuclear fuels is important for the safety of nuclear fuel storage and disposal. The diffusion of helium in UO 2 is revisited by using the DFT+U simulation methodology employing the “U-ramping” method to address the issue of metastable energy states. A novel diffusion mechanism by helium interstitials, the “asymmetric hop” mechanism, is reported and compared to other diffusion mechanisms including an oxygen vacancy mediated mechanism and available experimental diffusion data. We show that the new mechanism is the dominant one over a widemore » temperature range.« less

The Common Sense of Small Nuclear Arsenals

DTIC Science & Technology

2012-01-01

affairs. That pattern is continuing and, therefore, is worth examining. In this article I use structural theory to explain what I call “the com­ mon...deterrence and dis­ suasion and then explain small nuclear arsenals in terms of structural theory , relying most heavily on the effects of socialization...deterrence are particularly useful. Dissuasion and general deterrence share many common elements. Both are rooted in deterrence theory and share an

POTENTIAL CLIMATE WARMING EFFECTS ON ICE COVERS OF SMALL LAKES IN THE CONTIGUOUS U.S. (R824801)

EPA Science Inventory

2>Abstract2>

To simulate effects of projected climate change on ice covers of small lakes in the northern contiguous U.S., a process-based simulation model is applied. This winter ice/snow cover model is associated with a deterministic, one-dimensional year-round water tem...

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

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

Pacold, J. I.; Lukens, W. W.; Booth, C. H.

We report that nuclear weapons testing generates large volumes of glassy materials that influence the transport of dispersed actinides in the environment and may carry information on the composition of the detonated device. We determine the oxidation state of U and Fe (which is known to buffer the oxidation state of actinide elements and to affect the redox state of groundwater) in samples of melt glass collected from three U.S. nuclear weapons tests. For selected samples, we also determine the coordination geometry of U and Fe, and we report the oxidation state of Pu from one melt glass sample. Wemore » find significant variations among the melt glass samples and, in particular, find a clear deviation in one sample from the expected buffering effect of Fe(II)/Fe(III) on the oxidation state of uranium. In the first direct measurement of Pu oxidation state in a nuclear test melt glass, we obtain a result consistent with existing literature that proposes Pu is primarily present as Pu(IV) in post-detonation material. In addition, our measurements imply that highly mobile U(VI) may be produced in significant quantities when melt glass is quenched rapidly following a nuclear detonation, though these products may remain immobile in the vitrified matrices. The observed differences in chemical state among the three samples show that redox conditions can vary dramatically across different nuclear test conditions. The local soil composition, associated device materials, and the rate of quenching are all likely to affect the final redox state of the glass. Lastly, the resulting variations in glass chemistry are significant for understanding and interpreting debris chemistry and the later environmental mobility of dispersed material.« less

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

DOE PAGES

Pacold, J. I.; Lukens, W. W.; Booth, C. H.; ...

2016-05-18

We report that nuclear weapons testing generates large volumes of glassy materials that influence the transport of dispersed actinides in the environment and may carry information on the composition of the detonated device. We determine the oxidation state of U and Fe (which is known to buffer the oxidation state of actinide elements and to affect the redox state of groundwater) in samples of melt glass collected from three U.S. nuclear weapons tests. For selected samples, we also determine the coordination geometry of U and Fe, and we report the oxidation state of Pu from one melt glass sample. Wemore » find significant variations among the melt glass samples and, in particular, find a clear deviation in one sample from the expected buffering effect of Fe(II)/Fe(III) on the oxidation state of uranium. In the first direct measurement of Pu oxidation state in a nuclear test melt glass, we obtain a result consistent with existing literature that proposes Pu is primarily present as Pu(IV) in post-detonation material. In addition, our measurements imply that highly mobile U(VI) may be produced in significant quantities when melt glass is quenched rapidly following a nuclear detonation, though these products may remain immobile in the vitrified matrices. The observed differences in chemical state among the three samples show that redox conditions can vary dramatically across different nuclear test conditions. The local soil composition, associated device materials, and the rate of quenching are all likely to affect the final redox state of the glass. Lastly, the resulting variations in glass chemistry are significant for understanding and interpreting debris chemistry and the later environmental mobility of dispersed material.« less

Inhibition of U snRNP assembly by a virus-encoded proteinase.

PubMed

Almstead, Laura L; Sarnow, Peter

2007-05-01

It has been proposed that defects in the assembly of spliceosomal uridine-rich small nuclear ribonucleoprotein (U snRNP) complexes could account for the death of motor neurons in spinal muscular atrophy (SMA). We discovered that infection of cultured cells with poliovirus results in the specific cleavage of the host factor Gemin3 by a virus-encoded proteinase, 2A(pro). Gemin3 is a component of the macromolecular SMN complex that mediates assembly of U snRNP complexes by aiding the heptameric oligomerization of Sm proteins onto U snRNAs. Using in vitro Sm core assembly assays, we found that lowering the intracellular amounts of Gemin3 by either poliovirus infection or small interfering RNA (siRNA)-mediated knockdown of Gemin3 resulted in reduced assembly of U snRNPs. Immunofluorescence analyses revealed a specific redistribution of Sm proteins from the nucleoplasm to the cytoplasmic periphery of the nucleus in poliovirus-infected cells. We propose that defects in U snRNP assembly may be shared features of SMA and poliomyelitis.

Alternative exon definition events control the choice between nuclear retention and cytoplasmic export of U11/U12-65K mRNA

PubMed Central

Verbeeren, Jens; Verma, Bhupendra

2017-01-01

Cellular homeostasis of the minor spliceosome is regulated by a negative feed-back loop that targets U11-48K and U11/U12-65K mRNAs encoding essential components of the U12-type intron-specific U11/U12 di-snRNP. This involves interaction of the U11 snRNP with an evolutionarily conserved splicing enhancer giving rise to unproductive mRNA isoforms. In the case of U11/U12-65K, this mechanism controls the length of the 3′ untranslated region (3′UTR). We show that this process is dynamically regulated in developing neurons and some other cell types, and involves a binary switch between translation-competent mRNAs with a short 3′UTR to non-productive isoforms with a long 3′UTR that are retained in the nucleus or/and spliced to the downstream amylase locus. Importantly, the choice between these alternatives is determined by alternative terminal exon definition events regulated by conserved U12- and U2-type 5′ splice sites as well as sequence signals used for pre-mRNA cleavage and polyadenylation. We additionally show that U11 snRNP binding to the U11/U12-65K mRNA species with a long 3′UTR is required for their nuclear retention. Together, our studies uncover an intricate molecular circuitry regulating the abundance of a key spliceosomal protein and shed new light on the mechanisms limiting the export of non-productively spliced mRNAs from the nucleus to the cytoplasm. PMID:28549066

Alternative exon definition events control the choice between nuclear retention and cytoplasmic export of U11/U12-65K mRNA.

PubMed

Verbeeren, Jens; Verma, Bhupendra; Niemelä, Elina H; Yap, Karen; Makeyev, Eugene V; Frilander, Mikko J

2017-05-01

Cellular homeostasis of the minor spliceosome is regulated by a negative feed-back loop that targets U11-48K and U11/U12-65K mRNAs encoding essential components of the U12-type intron-specific U11/U12 di-snRNP. This involves interaction of the U11 snRNP with an evolutionarily conserved splicing enhancer giving rise to unproductive mRNA isoforms. In the case of U11/U12-65K, this mechanism controls the length of the 3' untranslated region (3'UTR). We show that this process is dynamically regulated in developing neurons and some other cell types, and involves a binary switch between translation-competent mRNAs with a short 3'UTR to non-productive isoforms with a long 3'UTR that are retained in the nucleus or/and spliced to the downstream amylase locus. Importantly, the choice between these alternatives is determined by alternative terminal exon definition events regulated by conserved U12- and U2-type 5' splice sites as well as sequence signals used for pre-mRNA cleavage and polyadenylation. We additionally show that U11 snRNP binding to the U11/U12-65K mRNA species with a long 3'UTR is required for their nuclear retention. Together, our studies uncover an intricate molecular circuitry regulating the abundance of a key spliceosomal protein and shed new light on the mechanisms limiting the export of non-productively spliced mRNAs from the nucleus to the cytoplasm.

Affordable Development and Demonstration of a Small Nuclear Thermal Rocket (NTR) Engine and Stage: How Small Is Big Enough?

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Sefcik, Robert J.; Fittje, James E.; McCurdy, David R.; Qualls, Arthur L.; Schnitzler, Bruce G.; Werner, James E.; Weitzberg, Abraham; Joyner, Claude R.

2016-01-01

The Nuclear Thermal Rocket (NTR) derives its energy from fission of uranium-235 atoms contained within fuel elements that comprise the engine's reactor core. It generates high thrust and has a specific impulse potential of approximately 900 specific impulse - a 100 percent increase over today's best chemical rockets. The Nuclear Thermal Propulsion (NTP) project, funded by NASA's Advanced Exploration Systems (AES) program, includes five key task activities: (1) Recapture, demonstration, and validation of heritage graphite composite (GC) fuel (selected as the Lead Fuel option); (2) Engine Conceptual Design; (3) Operating Requirements Definition; (4) Identification of Affordable Options for Ground Testing; and (5) Formulation of an Affordable Development Strategy. During fiscal year (FY) 2014, a preliminary Design Development Test and Evaluation (DDT&E) plan and schedule for NTP development was outlined by the NASA Glenn Research Center (GRC), Department of Energy (DOE) and industry that involved significant system-level demonstration projects that included Ground Technology Demonstration (GTD) tests at the Nevada National Security Site (NNSS), followed by a Flight Technology Demonstration (FTD) mission. To reduce cost for the GTD tests and FTD mission, small NTR engines, in either the 7.5 or 16.5 kilopound-force thrust class, were considered. Both engine options used GC fuel and a common fuel element (FE) design. The small approximately 7.5 kilopound-force criticality-limited engine produces approximately157 thermal megawatts and its core is configured with parallel rows of hexagonal-shaped FEs and tie tubes (TTs) with a FE to TT ratio of approximately 1:1. The larger approximately 16.5 kilopound-force Small Nuclear Rocket Engine (SNRE), developed by Los Alamos National Laboratory (LANL) at the end of the Rover program, produces approximately 367 thermal megawatts and has a FE to TT ratio of approximately 2:1. Although both engines use a common 35-inch (approximately

Functional base-pairing interaction between highly conserved elements of U3 small nucleolar RNA and the small ribosomal subunit RNA.

PubMed

Hughes, J M

1996-06-21

The U3 nucleolar RNA has a remarkably wide phyletic distribution extending from the Eukarya to the Archaea. It functions in maturation of the small subunit (SSU) rRNA through a mechanism which is as yet unknown but which involves base-pairing with pre-rRNA. The most conserved part of U3 is within 30 nucleotides of the 5' end, but as yet no function for this domain has been proposed. Elements within this domain are complementary to highly conserved sequences in the SSU rRNA which, in the mature form, fold into a universally conserved pseudoknot. The nature of the complementarity suggests a novel mechanism for U3 function whereby U3 facilitates correct folding of the pseudoknot. Wide phylogenetic comparison provides compelling evidence in support of the interaction in that significant complementary changes have taken place, particularly in the archaeon Sulfolobus, which maintain the base-pairing. Base-substitution mutations in yeast U3 designed to disrupt the base-pairing indicate that the interaction is probably essential. These include cold-sensitivity mutations which exhibit phenotypes similar to U3-depletion, but without impairment of the AO processing step, which occurs within the 5' ETS. These phenotypes are consistent with the destabilization of SSU precursors and partial impairment of the processing steps A1, at the 5' ETS/18 S boundary, and A2, within the ITS1.

The effect of aluminum additions on the oxidation resistance of U 3Si 2

DOE PAGES

Wood, E. Sooby; White, J. T.; Nelson, A. T.

2017-04-01

The effect of aluminum additions to U 3Si 2 is investigated in this paper as a means to improve the oxidation resistance of this nuclear fuel form. Four U-Si-Al compositions have been synthesized and characterized using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The onsets of breakaway oxidation are identified in air thermal ramp tests using thermogravimetric analysis. The final oxidation products following 1000° C air exposure are identified using x-ray diffraction and compared to those of UO 2 and U metal oxidized in the same manner. Finally, thermogravimetric data acquired in this study indicates that increasing amountsmore » of Al in U 3Si 2 further delays the onset of breakaway oxidation, providing enhanced oxidation resistance in air. Al 2O 3 formation on U 3Al 2Si 3 is observed following a heat treatment performed at 500° C in air, demonstrating the potential of Al additions to improve the oxidation resistance of U 3Si 2.« less

The effect of aluminum additions on the oxidation resistance of U 3Si 2

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

Wood, E. Sooby; White, J. T.; Nelson, A. T.

The effect of aluminum additions to U 3Si 2 is investigated in this paper as a means to improve the oxidation resistance of this nuclear fuel form. Four U-Si-Al compositions have been synthesized and characterized using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The onsets of breakaway oxidation are identified in air thermal ramp tests using thermogravimetric analysis. The final oxidation products following 1000° C air exposure are identified using x-ray diffraction and compared to those of UO 2 and U metal oxidized in the same manner. Finally, thermogravimetric data acquired in this study indicates that increasing amountsmore » of Al in U 3Si 2 further delays the onset of breakaway oxidation, providing enhanced oxidation resistance in air. Al 2O 3 formation on U 3Al 2Si 3 is observed following a heat treatment performed at 500° C in air, demonstrating the potential of Al additions to improve the oxidation resistance of U 3Si 2.« less

History of Fire Events in the U.S. Commercial Nuclear Industry

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

Bijan Najafi; Joglar-Biloch, Francisco; Kassawara, Robert P.

2002-07-01

Over the past decade, interest in performance-based fire protection has increased within the nuclear industry. In support of this growing interest, in 1997 the Electric Power Research Institute (EPRI) developed a long-range plan to develop/improve data and tools needed to support Risk-Informed/Performance-Based fire protection. This plan calls for continued improvement in collection and use of information obtained from fire events at nuclear plants. The data collection process has the objectives of improving the insights gained from such data and reducing the uncertainty in fire risk and fire modeling methods in order to make them a more reliable basis for performancemore » based fire protection programs. In keeping with these objectives, EPRI continues to collect, review and analyze fire events in support of the nuclear industry. EPRI collects these records in cooperation with the Nuclear Electric Insurance Limited (NEIL), by compiling public fire event reports and by direct solicitation of U.S. nuclear facilities. EPRI fire data collection project is based on the principle that the understanding of history is one of the cornerstones of improving fire protection technology and practice. Therefore, the goal has been to develop and maintain a comprehensive database of fire events with flexibility to support various aspects of fire protection engineering. With more than 1850 fire records over a period of three decades and 2400 reactor years, this is the most comprehensive database of nuclear power industry fire events in existence today. In general, the frequency of fires in the U.S. commercial nuclear industry remains constant. In few cases, e.g., transient fires and fires in BWR offgas/recombiner systems, where either increasing or decreasing trends are observed, these trends tend to slow after 1980. The key issues in improving quality of the data remain to be consistency of the recording and reporting of fire events and difficulties in collection of records

What Are the Security Threats to Further Development of Nuclear Power Plants in the U.S.

DTIC Science & Technology

2010-03-01

as-a-secure- fuel -alternative &catid=94:0409content&itemid=342. (accessed May 2009). Bush, President George W. “Expand the Circle of Development by...SECURITY THREATS TO FURTHER DEVELOPMENT OF NUCLEAR POWER PLANTS IN THE U.S.? by Tammie L. Nottestad March 2010 Thesis Advisor: Robert Looney...Master’s Thesis 4. TITLE AND SUBTITLE What Are the Security Threats to Further Development of Nuclear Power Plants in the U.S.? 6. AUTHOR(S

Positive nuclear BAP1 immunostaining helps differentiate non-small cell lung carcinomas from malignant mesothelioma

PubMed Central

Carbone, Michele; Shimizu, David; Napolitano, Andrea; Tanji, Mika; Pass, Harvey I.; Yang, Haining; Pastorino, Sandra

2016-01-01

The differential diagnosis between pleural malignant mesothelioma (MM) and lung cancer is often challenging. Immunohistochemical (IHC) stains used to distinguish these malignancies include markers that are most often positive in MM and less frequently positive in carcinomas, and vice versa. However, in about 10–20% of the cases, the IHC results can be confusing and inconclusive, and novel markers are sought to increase the diagnostic accuracy. We stained 45 non-small cell lung cancer samples (32 adenocarcinomas and 13 squamous cell carcinomas) with a monoclonal antibody for BRCA1-associated protein 1 (BAP1) and also with an IHC panel we routinely use to help differentiate MM from carcinomas, which include, calretinin, Wilms Tumor 1, cytokeratin 5, podoplanin D2-40, pankeratin CAM5.2, thyroid transcription factor 1, Napsin-A, and p63. Nuclear BAP1 expression was also analyzed in 35 MM biopsies. All 45 non-small cell lung cancer biopsies stained positive for nuclear BAP1, whereas 22/35 (63%) MM biopsies lacked nuclear BAP1 staining, consistent with previous data. Lack of BAP1 nuclear staining was associated with MM (two-tailed Fisher's Exact Test, P = 5.4 × 10−11). Focal BAP1 staining was observed in a subset of samples, suggesting polyclonality. Diagnostic accuracy of other classical IHC markers was in agreement with previous studies. Our study indicated that absence of nuclear BAP1 stain helps differentiate MM from lung carcinomas. We suggest that BAP1 staining should be added to the IHC panel that is currently used to distinguish these malignancies. PMID:27447750

76 FR 47613 - Board Meeting: September 13-14, 2011-Salt Lake City, UT; the U.S. Nuclear Waste Technical Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-05

... NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Meeting: September 13-14, 2011--Salt Lake City, UT; the U.S. Nuclear Waste Technical Review Board Will Meet To Discuss DOE Plans for Used Fuel Disposition R... Amendments Act of 1987, the U.S. Nuclear Waste Technical Review Board will hold a public meeting in Salt Lake...

A New Class of Orthosteric uPAR•uPA Small-Molecule Antagonists Are Allosteric Inhibitors of the uPAR•Vitronectin Interaction

PubMed Central

Liu, Degang; Zhou, Donghui; Wang, Bo; Knabe, William Eric; Meroueh, Samy O.

2015-01-01

The urokinase receptor (uPAR) is a GPI-anchored cell surface receptor that is at the center of an intricate network of protein-protein interactions. Its immediate binding partners are the serine proteinase urokinase (uPA), and vitronectin (VTN), a component of the extracellular matrix. uPA and VTN bind at distinct sites on uPAR to promote extracellular matrix degradation and integrin signaling, respectively. Here, we report the discovery of a new class of pyrrolone small-molecule inhibitors of the tight ∼1 nM uPAR•uPA protein-protein interaction. These compounds were designed to bind to the uPA pocket on uPAR. The highest affinity compound, namely 7, displaced a fluorescently-labeled α-helical peptide (AE147-FAM) with an inhibition constant Ki of 0.7 µM and inhibited the tight uPAR•uPAATF interaction with an IC50 of 18 µM. Biophysical studies with surface plasmon resonance showed that VTN binding is highly dependent on uPA. This cooperative binding was confirmed as 7, which binds at the uPAR•uPA interface, also inhibited the distal VTN•uPAR interaction. In cell culture, 7 blocked the uPAR•uPA interaction in uPAR-expressing human embryonic kidney (HEK-293) cells, and impaired cell adhesion to VTN, a process that is mediated by integrins. As a result, 7 inhibited integrin signaling in MDA-MB-231 cancer cells as evidenced by a decrease in focal adhesion kinase (FAK) phosphorylation and Rac1 GTPase activation. Consistent with these results, 7 blocked breast MDA-MB-231 cancer cell invasion with IC50 values similar to those observed in ELISA and surface plasmon resonance competition studies. Explicit-solvent molecular dynamics simulations show that the cooperativity between uPA and VTN is attributed to stabilization of uPAR motion by uPA. In addition, free energy calculations revealed that uPA stabilizes the VTN•uPARSMB interaction through more favorable electrostatics and entropy. Disruption of the uPAR•VTNSMB interaction by 7 is consistent with the

A new class of orthosteric uPAR·uPA small-molecule antagonists are allosteric inhibitors of the uPAR·vitronectin interaction.

PubMed

Liu, Degang; Zhou, Donghui; Wang, Bo; Knabe, William Eric; Meroueh, Samy O

2015-06-19

The urokinase receptor (uPAR) is a GPI-anchored cell surface receptor that is at the center of an intricate network of protein-protein interactions. Its immediate binding partners are the serine proteinase urokinase (uPA), and vitronectin (VTN), a component of the extracellular matrix. uPA and VTN bind at distinct sites on uPAR to promote extracellular matrix degradation and integrin signaling, respectively. Here, we report the discovery of a new class of pyrrolone small-molecule inhibitors of the tight ∼1 nM uPAR·uPA protein-protein interaction. These compounds were designed to bind to the uPA pocket on uPAR. The highest affinity compound, namely 7, displaced a fluorescently labeled α-helical peptide (AE147-FAM) with an inhibition constant Ki of 0.7 μM and inhibited the tight uPAR·uPAATF interaction with an IC50 of 18 μM. Biophysical studies with surface plasmon resonance showed that VTN binding is highly dependent on uPA. This cooperative binding was confirmed as 7, which binds at the uPAR·uPA interface, also inhibited the distal VTN·uPAR interaction. In cell culture, 7 blocked the uPAR·uPA interaction in uPAR-expressing human embryonic kidney (HEK-293) cells and impaired cell adhesion to VTN, a process that is mediated by integrins. As a result, 7 inhibited integrin signaling in MDA-MB-231 cancer cells as evidenced by a decrease in focal adhesion kinase (FAK) phosphorylation and Rac1 GTPase activation. Consistent with these results, 7 blocked breast MDA-MB-231 cancer cell invasion with IC50 values similar to those observed in ELISA and surface plasmon resonance competition studies. Explicit-solvent molecular dynamics simulations show that the cooperativity between uPA and VTN is attributed to stabilization of uPAR motion by uPA. In addition, free energy calculations revealed that uPA stabilizes the VTNSMB·uPAR interaction through more favorable electrostatics and entropy. Disruption of the uPAR·VTNSMB interaction by 7 is consistent with the

Small modular reactor modeling using modelica for nuclear-renewable hybrid energy systems applications

DOE PAGES

Mikkelson, Daniel; Chang, Chih -Wei; Cetiner, Sacit M.; ...

2015-10-01

Here, the U.S. Department of Energy (DOE) supports research and development (R&D) that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options, to meet grid demand and industrial thermal energy needs [1]. One hybridization approach being investigated by the DOE Offices of Nuclear Energy (NE) and the DOE Energy Efficiency and Renewable Energy (EERE) is tighter coupling of nuclear and renewable energy sources to better manage overall energy use for the combined electricity, industrial manufacturing, and transportation sectors.

Redefining the U.S. Agenda for Nuclear Disarmament, Analysis and Reflections

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

Dunn, Lewis A.

With Lewis Dunn’s paper on nuclear disarmament diplomacy, we are inaugurating a new monograph series under the auspices of the Center for Global Security Research at Lawrence Livermore National Laboratory. The series will explore complex emerging challenges in the emerging security environment as they bear on issues of deterrence, assurance, and strategic stability. Our goal is to explore these issues deeply enough to provide significant new understanding that is technically informed and policy relevant. Our premise is that thoughtful students of international security affairs continue to value such in-depth analysis as a way to help make sense of the largemore » flow of data and opinion that reaches all of us on a daily basis. Our ambition is to generate four to six such papers per year on especially salient topics. The views expressed in these papers are those of the author and should not be attributed to the Center, the Laboratory, or the U.S. government. This inaugural paper addresses one of the key questions facing national leadership seven to eight years after President Obama’s April 2009 remarks in Prague and his commitment to take practical steps towards the long-term goal of the elimination of nuclear weapons. In the interim, some important steps have been taken. But there have also been many disappointments. The new presidential administration will face a security landscape quite different from that of eight years ago and must reassess U.S. priorities and approaches. As Lewis Dunn argues, some will be tempted to walk away entirely from the disarmament agenda, while others will advocate even more forcefully for unilateral U.S. steps to further reduce the role and number of nuclear weapons in its posture. Dr. Dunn sets out his own vision of how to adapt and carry forward the disarmament agenda, in a manner informed by developments in the security environment that point to a continuing role for nuclear deterrence. The result is both fresh and

ORNL experience and perspectives related to processing of thorium and 233U for nuclear fuel

DOE PAGES

Croff, Allen G.; Collins, Emory D.; Del Cul, G. D.; ...

2016-05-01

Thorium-based nuclear fuel cycles have received renewed attention in both research and public circles since about the year 2000. Much of the attention has been focused on nuclear fission energy production that utilizes thorium as a fertile element for producing fissionable 233U for recycle in thermal reactors, fast reactors, or externally driven systems. Here, lesser attention has been paid to other fuel cycle operations that are necessary for implementation of a sustainable thorium-based fuel cycle such as reprocessing and fabrication of recycle fuels containing 233U.

Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2O 7

DOE PAGES

Odoh, Samuel O.; Shamblin, Jacob; Colla, Christopher A.; ...

2016-03-14

Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced in the western USA. The drums contained an unexpected X-ray amorphous reactive form of uranium oxide, U 2O7. Heating hydrated uranyl peroxides produced during in situ mining unintentionally produced U 2O 7. It is a hygroscopic anhydrous uranyl peroxide that reacts rapidly with water to release O 2 gas and form metaschoepite, a uranyl-oxide hydrate. Quantum chemical calculations indicate that the most stable U 2O 7 conformer consists of two bent (UO 2) 2+ uranyl ions bridged by a peroxide group bidentatemore » and parallel to each uranyl ion, and a μ2-O atom, resulting in charge neutrality. A pair distribution function from neutron total scattering supports this structural model. The reactivity of U 2O 7 in water and with water in air is much higher than other uranium oxides, and this can be both hazardous and potentially advantageous in the nuclear fuel cycle.« less

Why are U.S. nuclear weapon modernization efforts controversial?

NASA Astrophysics Data System (ADS)

Acton, James

2016-03-01

U.S. nuclear weapon modernization programs are focused on extending the lives of existing warheads and developing new delivery vehicles to replace ageing bombers, intercontinental ballistic missiles, and ballistic missile submarines. These efforts are contested and controversial. Some critics argue that they are largely unnecessary, financially wasteful and potentially destabilizing. Other critics posit that they do not go far enough and that nuclear weapons with new military capabilities are required. At its core, this debate centers on three strategic questions. First, what roles should nuclear weapons be assigned? Second, what military capabilities do nuclear weapons need to fulfill these roles? Third, how severe are the unintended escalation risks associated with particular systems? Proponents of scaled-down modernization efforts generally argue for reducing the role of nuclear weapons but also that, even under existing policy, new military capabilities are not required. They also tend to stress the escalation risks of new--and even some existing--capabilities. Proponents of enhanced modernization efforts tend to advocate for a more expansive role for nuclear weapons in national security strategy. They also often argue that nuclear deterrence would be enhanced by lower yield weapons and/or so called bunker busters able to destroy more deeply buried targets. The debate is further fueled by technical disagreements over many aspects of ongoing and proposed modernization efforts. Some of these disagreements--such as the need for warhead life extension programs and their necessary scope--are essentially impossible to resolve at the unclassified level. By contrast, unclassified analysis can help elucidate--though not answer--other questions, such as the potential value of bunker busters.

Non-covalent Small-Molecule Kelch-like ECH-Associated Protein 1-Nuclear Factor Erythroid 2-Related Factor 2 (Keap1-Nrf2) Inhibitors and Their Potential for Targeting Central Nervous System Diseases.

PubMed

Pallesen, Jakob S; Tran, Kim T; Bach, Anders

2018-05-29

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) has a protective effect against oxidative stress and plays a major role in inflammation and central nervous system (CNS) diseases. Inhibition of the protein-protein interaction (PPI) between Nrf2 and its repressor protein, Kelch-like ECH-associated protein 1 (Keap1), leads to translocation of Nrf2 from the cytosol to the nucleus and expression of detoxifying antioxidant enzymes. To date, several non-covalent small-molecule Keap1-Nrf2 inhibitors have been identified; however, many of them contain carboxylic acids and are rather large in size, which likely prevents or decreases CNS permeability. This Perspective describes current small-molecule Keap1-Nrf2 inhibitors with experimental evidence for the ability to inhibit the Keap1-Nrf2 interaction by binding to Keap1 in a non-covalent manner. Binding data, biostructural studies, and biological activity are summarized for the inhibitors, and their potential as CNS tool compounds is discussed by analyzing physicochemical properties, including CNS multiparameter optimization (MPO) scoring algorithms. Finally, several strategies for identifying CNS-targeting Keap1 inhibitors are described.

The radiological impact of electricity generation by U.K. coal and nuclear systems.

PubMed

Robson, A

1984-05-01

Radiological impact is discussed for U.K. coal and nuclear power cycles under normal operation. The type having the greater impact depends on the radiological basis of the comparison, the particular nuclear reactor system considered and whether or not the whole fuel cycle, especially irradiated nuclear fule reprocessing , is included in the analysis. More importantly, the various impacts are shown to be generally acceptable in an absolute sense i.e. exposures are less than and usually low in comparison with radiological safety guidelines and everyday natural radiation exposures.

Sound velocity measurement of nuclear-ordered U2D2 solid 3He along the melting curve

NASA Astrophysics Data System (ADS)

Nomura, R.; Suzuki, M.; Yamaguchi, M.; Sasaki, Y.; Mizusaki, T.

2000-05-01

The sound velocity of a single-domain 3He crystal was measured in the nuclear-ordered low-field phase and the paramagnetic phase along the melting curve, using 10.98 MHz longitudinal sound. The temperature dependence of the sound velocity along the melting curve was explained by a nuclear spin contribution and the molar volume change along the melting curve. By comparing the measured velocity with thermodynamic quantities, we extracted the Grüneizen constant for the exchange energy. The anisotropy of the velocity in the ordered phase was investigated for three samples and was found to be smaller than 2×10 -5 in Δ v/ v. The attenuation coefficient of the sound was much smaller than 0.2 cm-1.

Recent Developments in MC-ICP-MS for Uranium Isotopic Determination from Small Samples.

NASA Astrophysics Data System (ADS)

Field, P.; Lloyd, N. S.

2016-12-01

V002: Advances in approaches and instruments for isotope studies Session ID#: 12653 Recent Developments in MC-ICP-MS for Uranium Isotopic Determination from small samples.M. Paul Field 1 & Nicholas S. Lloyd. 1 Elemental Scientific Inc., Omaha, Nebraska, USA. field@icpms.com 2 Thermo Fisher Scientific, Hanna-Kunath-Str. 11, 28199 Bremen, Germany. nicholas.lloyd@thermofisher.com Uranium isotope ratio determination for nuclear, nuclear safeguards and for environmental applications can be challenging due to, 1) the large isotopic differences between samples and 2) low abundance of 234U and 236U. For some applications the total uranium quantities can be limited, or it is desirable to run at lower concentrations for radiological protection. Recent developments in inlet systems and detector technologies allow small samples to be analyzed at higher precisions using MC-ICP-MS. Here we evaluate the combination of Elemental Scientific apex omega desolvation system and microFAST-MC dual loop-loading flow-injection system with the Thermo Scientific NEPTUNE Plus MC-ICP-MS. The inlet systems allow for the automated syringe loading and injecting handling of small sample volumes with efficient desolvation to minimize the hydride interference on 236U. The highest ICP ion sampling efficiency is realized using the Thermo Scientific Jet Interface. Thermo Scientific 1013 ohm amplifier technology allows small ion beams to be measured at higher precision, offering the highest signal/noise ratio with a linear and stable response that covers a wide dynamic range (ca. 1 kcps - 30 Mcps). For nanogram quantities of low enriched and depleted uranium standards the 235U was measured with 1013 ohm amplifier technology. The minor isotopes (234U and 236U) were measured by SEM ion counters with RPQ lens filters, which offer the lowest detection limits. For sample amounts ca. 20 ng the minor isotopes can be moved onto 1013 ohm amplifiers and the 235U onto standard 1011 ohm amplifier. To illustrate the

77 FR 53769 - Receipts-Based, Small Business Size Standard; Confirmation of Effective Date

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-04

...-Based, Small Business Size Standard; Confirmation of Effective Date AGENCY: Nuclear Regulatory Commission. ACTION: Direct final rule; confirmation of effective date. SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is confirming the effective date of August 22, 2012, for the direct final rule that appeared...

Small Business Manufacturing--An Important Component of the U.S. Defense Industrial Base

DTIC Science & Technology

1993-04-01

Armed Forces in 1993, Mr. Williams is assigned to the Assistant Secretary of the Army (Financial Management ) in the Pentagon. - ii - SMALL BUSINESS ...AD-A276 756 1993 Executive Research Project RS1 Small Business Manufacturing -- An Important Component of the U.S. Defense Industrial Base Mr...paper comprises a review of the contribution of the small - and medium-sized manufacturing business sector to the US defense industrial base, the state

Import routes and nuclear functions of Argonaute and other small RNA-silencing proteins.

PubMed

Schraivogel, Daniel; Meister, Gunter

2014-09-01

Small RNAs are important regulators of gene expression in many different organisms. Nuclear and cytoplasmic biogenesis enzymes generate functional small RNAs from double-stranded (ds) or single-stranded (ss) RNA precursors, and mature small RNAs are loaded into Argonaute proteins. In the cytoplasm, small RNAs guide Argonaute proteins to complementary RNAs leading to cleavage of these targets, translational silencing, or mRNA decay. In the nucleus Argonaute proteins engage in transcriptional silencing processes such as epigenetic silencing of repetitive elements at the chromatin level. During the past few years many novel functions of small RNA-guided gene silencing proteins in the nucleus have been reported. However, their specific import routes are largely unknown. In this review we summarize the current knowledge on nuclear transport routes that Argonaute and other RNA-silencing proteins take to carry out their various functions in the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Facile CO Cleavage by a Multimetallic CsU2 Nitride Complex.

PubMed

Falcone, Marta; Kefalidis, Christos E; Scopelliti, Rosario; Maron, Laurent; Mazzanti, Marinella

2016-09-26

Uranium nitrides are important materials with potential for application as fuels for nuclear power generation, and as highly active catalysts. Molecular nitride compounds could provide important insight into the nature of the uranium-nitride bond, but currently little is known about their reactivity. In this study, we found that a complex containing a nitride bridging two uranium centers and a cesium cation readily cleaved the C≡O bond (one of the strongest bonds in nature) under ambient conditions. The product formed has a [CsU2 (μ-CN)(μ-O)] core, thus indicating that the three cations cooperate to cleave CO. Moreover, the addition of MeOTf to the nitride complex led to an exceptional valence disproportionation of the CsU(IV) -N-U(IV) core to yield CsU(III) (OTf) and [MeN=U(V) ] fragments. The important role of multimetallic cooperativity in both reactions is illustrated by the computed reaction mechanisms. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

2nd Iberian Nuclear Astrophysics Meeting on Compact Stars

NASA Astrophysics Data System (ADS)

Perez-Garcia, M. Angeles; Pons, Jose; Albertus, C.

2012-02-01

project FIS2011-14759 MICINN logo Instituto de Física Fundamental y Matemáticas (IUFFYM) IUFFYM logo Universidad de Salamanca, Spain USAL logo MULTIDARK Consolider-Ingenio 2010, MICINN ref. CSD2009-00064 MULTIDARK logo PICTURE OF PARTICIPANTS Participants picture Picture of some of the participants of the II Iberian Nuclear Astrophysics Meeting. LIST OF PARTICIPANTS C Albertus (U. Salamanca, Spain) I Bombaci (U. Pisa, Italy) Rudiney Casali (U. Coimbra, Portugal) Silvia Chiacchiera (U. Coimbra, Portugal) Anthea Fantina (U. Libre Bruxelles, Belgium) Marcio Ferreira (U. Coimbra, Portugal) Miguel Gullón (U. Alicante, Spain) Fabrizio Grill (U. Coimbra, Portugal) Joe Hughto (Indiana University, USA/ U. Alicante, Spain) J M Ibáñez (U. Valencia, Spain) B Juliá Díaz (U. Barcelona/ICFO) D Logoteta (U. Coimbra, Portugal) V Moreno (U. Autónoma de Madrid, Spain) M A Pérez-García (U. Salamanca, Spain) J Pons (U. Alicante, Spain) C Providencia (U. Coimbra, Portugal) Nanda Rea (ICE-CSIC, IEEC, Barcelona, Spain) Xavier Roca-Maza (INFN, Milano, Italy) Luis Roso (CLPU/ U. Salamanca, Spain) Klaas Vantournhout (GSI Darmstadt, Germany) I Vidaña (U. Coimbra, Portugal) Daniele Viganó (U. Alicante, Spain)

77 FR 6131 - Memorandum of Understanding Between the U.S. Nuclear Regulatory Commission and the Department of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-07

.... Background Nuclear Regulatory Commission Pursuant to Section 103 of the Atomic Energy Act of 1954, as amended... NUCLEAR REGULATORY COMMISSION DEPARTMENT OF HOMELAND SECURITY [NRC-2012-0015] Memorandum of Understanding Between the U.S. Nuclear Regulatory Commission and the Department of Homeland Security Regarding...

Projected Growth in Small-Scale, Fossil-Fueled Distributed Generation: Potential Implications for the U.S. Greenhouse Gas Inventory

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

Eberle, Annika; Heath, Garvin A

The generation capacity of small-scale (less than one megawatt) fossil-fueled electricity in the United States is anticipated to grow by threefold to twenty-fold from 2015 to 2040. However, in adherence with internationally agreed upon carbon accounting methods, the Environmental Protection Agency's (EPA's) U.S. Greenhouse Inventory (GHGI) does not currently attribute greenhouse gases (GHGs) from these small-scale distributed generation sources to the electric power sector and instead accounts for these emissions in the sector that uses the distributed generation (e.g., the commercial sector). In addition, no other federal electric-sector GHG emission data product produced by the EPA or the U.S. Energymore » Information Administration (EIA) can attribute these emissions to electricity. We reviewed the technical documentation for eight federal electric-sector GHG emission data products, interviewed the data product owners, collected their GHG emission estimates, and analyzed projections for growth in fossil-fueled distributed generation. We show that, by 2040, these small-scale generators could account for at least about 1%- 5% of total CO2 emissions from the U.S. electric power sector. If these emissions fall outside the electric power sector, the United States may not be able to completely and accurately track changes in electricity-related CO2 emissions, which could impact how the country sets GHG reduction targets and allocates mitigation resources. Because small-scale, fossil-fueled distributed generation is expected to grow in other countries as well, the results of this work also have implications for global carbon accounting.« less

The Small Nuclear Genomes of Selaginella Are Associated with a Low Rate of Genome Size Evolution.

PubMed

Baniaga, Anthony E; Arrigo, Nils; Barker, Michael S

2016-06-03

The haploid nuclear genome size (1C DNA) of vascular land plants varies over several orders of magnitude. Much of this observed diversity in genome size is due to the proliferation and deletion of transposable elements. To date, all vascular land plant lineages with extremely small nuclear genomes represent recently derived states, having ancestors with much larger genome sizes. The Selaginellaceae represent an ancient lineage with extremely small genomes. It is unclear how small nuclear genomes evolved in Selaginella We compared the rates of nuclear genome size evolution in Selaginella and major vascular plant clades in a comparative phylogenetic framework. For the analyses, we collected 29 new flow cytometry estimates of haploid genome size in Selaginella to augment publicly available data. Selaginella possess some of the smallest known haploid nuclear genome sizes, as well as the lowest rate of genome size evolution observed across all vascular land plants included in our analyses. Additionally, our analyses provide strong support for a history of haploid nuclear genome size stasis in Selaginella Our results indicate that Selaginella, similar to other early diverging lineages of vascular land plants, has relatively low rates of genome size evolution. Further, our analyses highlight that a rapid transition to a small genome size is only one route to an extremely small genome. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

The <u>Be>rkeley <u>A>tmospheric <u>C>O2 <u>O>bservation <u>N>etwork (BEACON): Measuring Greenhouse Gases and Criteria Pollutants within the Urban Dome

NASA Astrophysics Data System (ADS)

Teige, V. E.; Weichsel, K.; Hooker, A.; Wooldridge, P. J.; Cohen, R. C.

2012-12-01

Efforts to curb greenhouse gas emissions, while global in their impacts, often focus on local and regional scales for execution and are dependent on the actions of communities and individuals. Evaluating the effectiveness of local policies requires observations with much higher spatial resolution than are currently available---kilometer scale. The <u>Be>rkeley <u>A>tmospheric <u>C>O2 <u>O>bservation <u>N>etwork (BEACON):, launched at the end of 2011, aims to provide measurements of urban-scale concentrations of CO2, temperature, pressure, relative humidity, O3, CO, and NO2 with sufficient spatial and temporal resolution to characterize the sources of CO2 within cities. Our initial deployment in Oakland, California uses ~40 sensor packages at a roughly 2 km spacing throughout the city. We will present an initial analysis of the vertical gradients and other spatial patterns observed to date.

76 FR 77855 - Criteria for Identifying Material Licensees for the U. S. Nuclear Regulatory Commission's Agency...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

... Agencywide Documents Access and Management System (ADAMS) Accession Number: ML112280111) or in the... Management Programs, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-6272... ineffective in correcting their underlying issues. Discussion Criteria for Identifying Nuclear Material...

Analysis of aberrant pre-messenger RNA splicing resulting from mutations in ATP8B1 and efficient in vitro rescue by adapted U1 small nuclear RNA.

PubMed

van der Woerd, Wendy L; Mulder, Johanna; Pagani, Franco; Beuers, Ulrich; Houwen, Roderick H J; van de Graaf, Stan F J

2015-04-01

ATP8B1 deficiency is a severe autosomal recessive liver disease resulting from mutations in the ATP8B1 gene characterized by a continuous phenotypical spectrum from intermittent (benign recurrent intrahepatic cholestasis; BRIC) to progressive familial intrahepatic cholestasis (PFIC). Current therapeutic options are insufficient, and elucidating the molecular consequences of mutations could lead to personalized mutation-specific therapies. We investigated the effect on pre-messenger RNA splicing of 14 ATP8B1 mutations at exon-intron boundaries using an in vitro minigene system. Eleven mutations, mostly associated with a PFIC phenotype, resulted in aberrant splicing and a complete absence of correctly spliced product. In contrast, three mutations led to partially correct splicing and were associated with a BRIC phenotype. These findings indicate an inverse correlation between the level of correctly spliced product and disease severity. Expression of modified U1 small nuclear RNAs (snRNA) complementary to the splice donor sites strongly improved or completely rescued splicing for several ATP8B1 mutations located at donor, as well as acceptor, splice sites. In one case, we also evaluated exon-specific U1 snRNAs that, by targeting nonconserved intronic sequences, might reduce possible off-target events. Although very effective in correcting exon skipping, they also induced retention of the short downstream intron. We systematically characterized the molecular consequences of 14 ATP8B1 mutations at exon-intron boundaries associated with ATP8B1 deficiency and found that the majority resulted in total exon skipping. The amount of correctly spliced product inversely correlated with disease severity. Compensatory modified U1 snRNAs, complementary to mutated donor splice sites, were able to improve exon definition very efficiently and could be a novel therapeutic strategy in ATP8B1 deficiency as well as other genetic diseases. © 2014 by the American Association for the Study

U.S. Department of Energy facilities needed to advance nuclear power.

PubMed

Ahearne, John F

2011-01-01

This talk is based upon a November 2008 report by the U.S. Department of Energy (DOE) Nuclear Energy Advisory Committee (NEAC). The report has two parts, a policy section and a technology section. Here extensive material from the Technical Subcommittee section of the NEAC report is used. Copyright © 2010 Health Physics Society

Study on Ultra-Long Life,Small U-Zr Metallic Fuelled Core With Burnable Poison

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

Kenji Tsuji; Hiromitsu Inagaki; Akira Nishikawa

2002-07-01

A conceptual design for a 50 MWe sodium cooled, U-Pu-Zr metallic fuelled, fast reactor core, which aims at a core lifetime of 30 years, has been performed [1]. As for the compensation for a large burn-up reactivity through 30 years, an axially movable reflector, which is located around the core, carries the major part of it and a burnable poison does the rest. This concept has achieved not only a long core lifetime but also a high discharged burn-up. On this study, a conceptual design for a small fast reactor loading U-Zr metallic fuelled core instead of U-Pu-Zr fuelled coremore » has been conducted, based on the original core arrangement of 4S reactor [2]. Within the range of this study including safety requirements, adopting the burnable poison would be effective to construct a core concept that achieves both a long lifetime and a high discharged burn-up. (authors)« less

76 FR 9612 - GE Hitachi Nuclear Energy; Acceptance for Docketing of an Application for Renewal of the U.S...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-18

... NUCLEAR REGULATORY COMMISSION [Docket No. 52-045; NRC-2011-0020] GE Hitachi Nuclear Energy... Certification On December 7, 2010, GE Hitachi Nuclear Energy (GEH) submitted an application to the U.S. Nuclear... and Approvals for Nuclear Power Plants.'' A notice of receipt and availability of this application was...

A Study of Reasons for Participation in Continuing Professional Education in the U.S. Nuclear Power Industry

ERIC Educational Resources Information Center

McCamey, Randy B.

2003-01-01

The need for workers in the U.S. nuclear power industry to continually update their knowledge, skills, and abilities is critical to the safe and reliable operation of the country's nuclear power facilities. To improve their skills, knowledge, and abilities, many professionals in the nuclear power industry participate in continuing professional…

Civil Defense, U. S. A.: A Programmed Orientation to Civil Defense. Unit 2. Nuclear Weapons Effects and Shelter.

ERIC Educational Resources Information Center

Defense Civil Preparedness Agency (DOD), Battle Creek, MI.

Basic information about nuclear weapons is presented so that their effects can be meaningfully related to the defensive countermeasures which will be most effective against them. Major topics include: (1) Explosive power of nuclear weapons, (2) Major effects of nuclear explosions, (3) Two basic types of nuclear explosions, (4) Contrast between air…

Development of U-frame bending system for studying the vibration integrity of spent nuclear fuel

NASA Astrophysics Data System (ADS)

Wang, Hong; Wang, Jy-An John; Tan, Ting; Jiang, Hao; Cox, Thomas S.; Howard, Rob L.; Bevard, Bruce B.; Flanagan, Michelle

2013-09-01

A bending fatigue system developed to evaluate the response of spent nuclear fuel rods to vibration loads is presented. A U-frame testing setup is used for imposing bending loads on the fuel rod specimen. The U-frame setup consists of two rigid arms, side connecting plates to the rigid arms, and linkages to a universal testing machine. The test specimen's curvature is obtained through a three-point deflection measurement method. The tests using surrogate specimens with stainless steel cladding revealed increased flexural rigidity under unidirectional cyclic bending, significant effect of cladding-pellets bonding on the response of surrogate rods, and substantial cyclic softening in reverse bending mode. These phenomena may cast light on the expected response of a spent nuclear fuel rod. The developed U-frame system is thus verified and demonstrated to be ready for further pursuit in hot-cell tests.

Health consequences and health systems response to the Pacific U.S. Nuclear Weapons Testing Program.

PubMed

Palafox, Neal A; Riklon, Sheldon; Alik, Wilfred; Hixon, Allen L

2007-03-01

Between 1946 and 1958, the United States detonated 67 thermonuclear devices in the Pacific as part of their U.S. Nuclear Weapons Testing Program (USNWTP). The aggregate explosive power was equal to 7,200 Hiroshima atomic bombs. Recent documents released by the U.S. government suggest that the deleterious effects of the nuclear testing were greater and extended farther than previously known. The Republic of the Marshall Islands (RMI) government and affected communities have sought refress through diplomatic routes with the U.S. government, however, existing medical programs and financial reparations have not adequately addressed many of the health consequences of the USNWTP. Since radiation-induced cancers may have a long latency, a healthcare infrastructure is needed to address both cancer and related health issues. This article reviews the health consequences of the Pacific USNWTP and the current health systems ability to respond.

Impact of New Nuclear Data Libraries on Small Sized Long Life CANDLE HTGR Design Parameters

NASA Astrophysics Data System (ADS)

Liem, Peng Hong; Hartanto, Donny; Tran, Hoai Nam

2017-01-01

The impact of new evaluated nuclear data libraries (JENDL-4.0, ENDF/B-VII.0 and JEFF-3.1) on the core characteristics of small-sized long-life CANDLE High Temperature Gas-Cooled Reactors (HTGRs) with uranium and thorium fuel cycles was investigated. The most important parameters of the CANDLE core characteristics investigated here covered (1) infinite multiplication factor of the fresh fuel containing burnable poison, (2) the effective multiplication factor of the equilibrium core, (3) the moving velocity of the burning region, (4) the attained discharge burnup, and (5) the maximum power density. The reference case was taken from the current JENDL-3.3 results. For the uranium fuel cycle, the impact of the new libraries was small, while significant impact was found for thorium fuel cycle. The findings indicated the needs of more accurate nuclear data libraries for nuclides involved in thorium fuel cycle in the future.

A Delayed Neutron Counting System for the Analysis of Special Nuclear Materials

NASA Astrophysics Data System (ADS)

Sellers, Madison Theresa

Nuclear forensic analysis is a modem science that uses numerous analytical techniques to identify and attribute nuclear materials in the event of a nuclear explosion, radiological terrorist attack or the interception of illicit nuclear material smuggling. The Canadian Department of National Defence has participated in recent international exercises that have highlighted the Nation's requirement to develop nuclear forensics expertise, protocol and capabilities, specifically pertaining to the analysis of special nuclear materials (SNM). A delayed neutron counting (DNC) system has been designed and established at the Royal Military College of Canada (RMC) to enhance the Government's SNM analysis capabilities. This analytical technique complements those already at RMC by providing a rapid and non-destructive method for the analysis of the fissile isotopes of both uranium (U) and plutonium (Pu). The SLOWPOKE-2 reactor at RMC produces a predominately thermal neutron flux. These neutrons induce fission in the SNM isotopes 233U, 235U and 239Pu releasing prompt fast neutrons, energy and radioactive fission fragments. Some of these fission fragments undergo beta - decay and subsequently emit neutrons, which can be recorded by an array of sensitive 3He detectors. The significant time period between the fission process and the release of these neutrons results in their identification as 'delayed neutrons'. The recorded neutron spectrum varies with time and the count rate curve is unique to each fissile isotope. In-house software, developed by this project, can analyze this delayed neutron curve and provides the fissile mass in the sample. Extensive characterization of the DNC system has been performed with natural U samples with 235 U content ranging from 2--7 microg. The system efficiency and dead time behaviour determined by the natural uranium sample analyses were validated by depleted uranium samples with similar quantities of 235 U resulting in a typical relative error of

75 FR 14206 - FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-24

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-266 And 50-301; NRC-2010-0123 FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an Exemption, pursuant to...

U.S. Nuclear Power Plants: Continued Life or Replacement After 60? (released in AEO2010)

EIA Publications

2010-01-01

Nuclear power plants generate approximately 20% of U.S. electricity, and the plants in operation today are often seen as attractive assets in the current environment of uncertainty about future fossil fuel prices, high construction costs for new power plants (particularly nuclear plants), and the potential enactment of greenhouse gas regulations. Existing nuclear power plants have low fuel costs and relatively high power output. However, there is uncertainty about how long they will be allowed to continue operating.

A Small U-Shaped Bending-Induced Interference Optical Fiber Sensor for the Measurement of Glucose Solutions.

PubMed

Fang, Yu-Lin; Wang, Chen-Tung; Chiang, Chia-Chin

2016-09-09

The study proposes a small U-shaped bending-induced interference optical fiber sensor; this novel sensor is a probe-type sensor manufactured using a mechanical device, a heat source, optical fiber and a packaging module. This probe-type sensor overcomes the shortcomings of conventional optical fibers, including being difficult to repair and a tendency to be influenced by external forces. We manufactured three types of sensors with different curvature radiuses. Specifically, sensors with three radiuses (1.5 mm, 2.0 mm, and 3.0 mm) were used to measure common water and glucose solutions with concentrations of between 6% and 30% (the interval between concentrations was 4%). The results show that the maximal sensitivity was 0.85 dB/% and that the linearly-dependent coefficient was 0.925. The results further show that not only can the small U-shaped bending-induced interference optical fiber sensor achieve high sensitivity in the measurement of glucose solutions, but that it can also achieve great stability and repeatability.

Photofission cross-section ratio measurement of 235U/238U using monoenergetic photons in the energy range of 9.0-16.6 MeV

NASA Astrophysics Data System (ADS)

Krishichayan; Bhike, Megha; Finch, S. W.; Howell, C. R.; Tonchev, A. P.; Tornow, W.

2017-05-01

Photofission cross-section ratios of 235U and 238U have been measured using monoenergetic photon beams at the HIγS facility of TUNL. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. Measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

Development concept for a small, split-core, heat-pipe-cooled nuclear reactor

NASA Technical Reports Server (NTRS)

Lantz, E.; Breitwieser, R.; Niederauer, G. F.

1974-01-01

There have been two main deterrents to the development of semiportable nuclear reactors. One is the high development costs; the other is the inability to satisfy with assurance the questions of operational safety. This report shows how a split-core, heat-pipe cooled reactor could conceptually eliminate these deterrents, and examines and summarizes recent work on split-core, heat-pipe reactors. A concept for a small reactor that could be developed at a comparatively low cost is presented. The concept would extend the technology of subcritical radioisotope thermoelectric generators using 238 PuO2 to the evolution of critical space power reactors using 239 PuO2.

^2^3^8U/^2^3^5U Ratios of Anagrams: Angrites and Granites

NASA Astrophysics Data System (ADS)

Tissot, F. L. H.; Dauphas, N.

2012-03-01

We report ^2^3^8U/^2^3^5U ratios of five angrites and give the corresponding Pb-Pb ages of D'Orbigny and Angra Dos Reis. The U-isotopic composition of terrestrial granites (I, S, and A types) is also assessed to determine the influence of the protolith.

Detection and Identification of Small Seismic Events Following the 3 September 2017 UNT Around North Korean Nuclear Test Site

NASA Astrophysics Data System (ADS)

Kim, W. Y.; Richards, P. G.

2017-12-01

At least four small seismic events were detected around the North Korean nuclear test site following the 3 September 2017 underground nuclear test. The magnitude of these shocks range from 2.6 to 3.5. Based on their proximity to the September 3 UNT, these shocks may be considered as aftershocks of the UNT. We assess the best method to classify these small events based on spectral amplitude ratios of regional P and S wave from the shocks. None of these shocks are classified as explosion-like based on P/S spectral amplitude ratios. We examine additional possible small seismic events around the North Korean test site by using seismic data from stations in southern Korea and northeastern China including IMS seismic arrays, GSN stations, and regional network stations in the region.

Implementing a Nuclear Power Plant Model for Evaluating Load-Following Capability on a Small Grid

NASA Astrophysics Data System (ADS)

Arda, Samet Egemen

A pressurized water reactor (PWR) nuclear power plant (NPP) model is introduced into Positive Sequence Load Flow (PSLF) software by General Electric in order to evaluate the load-following capability of NPPs. The nuclear steam supply system (NSSS) consists of a reactor core, hot and cold legs, plenums, and a U-tube steam generator. The physical systems listed above are represented by mathematical models utilizing a state variable lumped parameter approach. A steady-state control program for the reactor, and simple turbine and governor models are also developed. Adequacy of the isolated reactor core, the isolated steam generator, and the complete PWR models are tested in Matlab/Simulink and dynamic responses are compared with the test results obtained from the H. B. Robinson NPP. Test results illustrate that the developed models represents the dynamic features of real-physical systems and are capable of predicting responses due to small perturbations of external reactivity and steam valve opening. Subsequently, the NSSS representation is incorporated into PSLF and coupled with built-in excitation system and generator models. Different simulation cases are run when sudden loss of generation occurs in a small power system which includes hydroelectric and natural gas power plants besides the developed PWR NPP. The conclusion is that the NPP can respond to a disturbance in the power system without exceeding any design and safety limits if appropriate operational conditions, such as achieving the NPP turbine control by adjusting the speed of the steam valve, are met. In other words, the NPP can participate in the control of system frequency and improve the overall power system performance.

Dynamic leaching studies of 48 MWd/kgU UO2 commercial spent nuclear fuel under oxic conditions

NASA Astrophysics Data System (ADS)

Serrano-Purroy, D.; Casas, I.; González-Robles, E.; Glatz, J. P.; Wegen, D. H.; Clarens, F.; Giménez, J.; de Pablo, J.; Martínez-Esparza, A.

2013-03-01

The leaching of a high-burn-up spent nuclear fuel (48 MWd/KgU) has been studied in a carbonate-containing solution and under oxic conditions using a Continuously Stirred Tank Flow-Through Reactor (CSTR). Two samples of the fuel, one prepared from the centre of the pellet (labelled CORE) and another one from the fuel pellet periphery, enriched with the so-called High Burn-Up Structure (HBS, labelled OUT) have been used.For uranium and actinides, the results showed that U, Np, Am and Cm gave very similar normalized dissolution rates, while Pu showed slower dissolution rates for both samples. In addition, dissolution rates were consistently two to four times lower for OUT sample compared to CORE sample.Considering the fission products release the main results are that Y, Tc, La and Nd dissolved very similar to uranium; while Cs, Sr, Mo and Rb have up to 10 times higher dissolution rates. Rh, Ru and Zr seemed to have lower dissolution rates than uranium. The lowest dissolution rates were found for OUT sample.Three different contributions were detected on uranium release, modelled and attributed to oxidation layer, fines and matrix release.

Loose Words, Not Nukes: The Impact of U.S. Nuclear Force Structure Debate on NATO Perceptions of Extended Deterrence

DTIC Science & Technology

2012-02-15

institutional mechanisms that may result in uncontrollable escalation in the belief there must be an irrevocable structural element of uncertainty...intentionally downplay the role of nuclear capabilities. Current U.S. strategy documents obliquely whisper nuclear linkages (if they are mentioned at...formally distance itself from the legacy (but still operative) NATO first-use declaratory policy.11 The express U.S. distinction exposes a fault line in

A High Accuracy Measurement of the Nuclear Decay of 235mU and Search for the Nuclear Decay of 229mTh

NASA Astrophysics Data System (ADS)

Ponce, Francisco

Among all nuclear decays, there exist two isomeric states with very low-energy that belong to . {229}Th (7.8 ± 0.5 eV) and . {235}U (76.8 ± 0.5 eV) . Of particular interest is . {229}Th, because the decay energy is in the ultraviolet, and therefore in the range of modern tunable lasers. The isomer can potentially be used as the basis for a nuclear clock that is expected to be two orders of magnitude more precise than atomic clocks. However, the . {229m}Th nuclear decay energy is not sufficiently well known to design the necessary laser system for a nuclear clock. This work describes the development of a new technique using superconducting tunnel junction (STJ) detectors to directly measure the nuclear decay of low-energy isomers with a high level of accuracy. The strength of the technique is demonstrated by measuring the decay energy of the . {235}U isomer at 76.737 ± 0.018 eV. Over an order of magnitude more accurate than the current literature value. The technique is then applied to detect the transition in . {229m}Th directly and measure its energy with comparable accuracy. These experiments are unsuccessful and are discussed in light of the recent measurement of the . {229m}Th half-life of 7 ± \\SI{1}{\\micro\\second}.

A compilation of nuclear weapons test detonation data for U.S. Pacific ocean tests.

PubMed

Simon, S L; Robison, W L

1997-07-01

Prior to December 1993, the explosive yields of 44 of 66 nuclear tests conducted by the United States in the Marshall Islands were still classified. Following a request from the Government of the Republic of the Marshall Islands to the U.S. Department of Energy to release this information, the Secretary of Energy declassified and released to the public the explosive yields of the Pacific nuclear tests. This paper presents a synopsis of information on nuclear test detonations in the Marshall Islands and other locations in the mid-Pacific including dates, explosive yields, locations, weapon placement, and summary statistics.

Neutrino mass with large S U (2 )L multiplet fields

NASA Astrophysics Data System (ADS)

Nomura, Takaaki; Okada, Hiroshi

2017-11-01

We propose an extension of the standard model introducing large S U (2 )L multiplet fields which are quartet and septet scalars and quintet Majorana fermions. These multiplets can induce the neutrino masses via interactions with the S U (2 ) doublet leptons. We then find the neutrino masses are suppressed by a small vacuum expectation value of the quartet/septet and an inverse of the quintet fermion mass, relaxing the Yukawa hierarchies among the standard model fermions. We also discuss collider physics at the Large Hadron Collider, considering the production of charged particles in these multiplets, and due to the effects of violating the custodial symmetry, some specific signatures can be found. Then, we discuss the detectability of these signals.

Performance Comparisons and Down Selection of Small Motors for Two-Blade Heliogyro Solar Sail 6U CubeSat

NASA Technical Reports Server (NTRS)

Wiwattananon, Peerawan; Bryant, Robert G.

2015-01-01

This report compiles a review of 130 commercial small scale motors (piezoelectric and electric motors) and almost 20 researched-type small scale piezoelectricmotors for potential use in a 2 blades Heliogyro Solar Sail 6U CubeSat. In this application, a motor and gearhead (drive system) will deploy a roll of solar sailthin film (2 um thick)accommodated in a 2U CubeSat (100 x 200 x 100 mm) housing. The application requirements are: space rated, output torque at fulldeployment of 0.8 Nm, reel speed of 3 rpm, drive system weight limited to 150 grams, diameter limited to 50 mm, and the length not to exceed 40 mm. The 50mm diameter limit was imposed as motors with larger diameters would likely weigh too much and use more space on the satellite wall. This would limit theamount of the payload. The motors performance are compared between small scale, volume within 3x102 cm3 (3x105 mm3), commercial electric DC motors,commercial piezoelectric motors, and researched-type (non-commercial) piezoelectric motors extracted from scientific and product literature. The comparisonssuggest that piezoelectric motors without a gearhead exhibit larger output torque with respect to their volume and weight and require less input power toproduce high torque. A commercially available electric motor plus a gearhead was chosen through a proposed selection process to meet the applications designrequirements.

U.S. Department of Energy Office of Nuclear Technology Research and Eevelopment ((NTRD) comprehensive summary of QA assessments for FY17

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

Trost, Alan L.

The U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) has developed a research and development (R&D) roadmap for its research, development, and demonstration (RD&D) activities to ensure nuclear energy remains a compelling and viable energy option for the U.S. The roadmap defines NE RD&D activities and objectives that address the challenges to research, develop and demonstrate options to the current U.S commercial fuel cycle to enable the safe, secure, economic, and sustainable expansion of nuclear energy, while minimizing proliferation and terrorism risks expanding the use of nuclear power. The roadmap enables the development of technologies and other solutionsmore » that can improve the reliability, sustain the safety, and extend the life of current reactors. In addition, it will help to develop improvements in the affordability of the new reactors to enable nuclear energy to help meet the Administration’s energy security and climate change goals.« less

First measurements of (236)U concentrations and (236)U/(239)Pu isotopic ratios in a Southern Hemisphere soil far from nuclear test or reactor sites.

PubMed

Srncik, M; Tims, S G; De Cesare, M; Fifield, L K

2014-06-01

The variation of the (236)U and (239)Pu concentrations as a function of depth has been studied in a soil profile at a site in the Southern Hemisphere well removed from nuclear weapon test sites. Total inventories of (236)U and (239)Pu as well as the (236)U/(239)Pu isotopic ratio were derived. For this investigation a soil core from an undisturbed forest area in the Herbert River catchment (17°30' - 19°S) which is located in north-eastern Queensland (Australia) was chosen. The chemical separation of U and Pu was carried out with a double column which has the advantage of the extraction of both elements from a relatively large soil sample (∼20 g) within a day. The samples were measured by Accelerator Mass Spectrometry using the 14UD pelletron accelerator at the Australian National University. The highest atom concentrations of both (236)U and (239)Pu were found at a depth of 2-3 cm. The (236)U/(239)Pu isotopic ratio in fallout at this site, as deduced from the ratio of the (236)U and (239)Pu inventories, is 0.085 ± 0.003 which is clearly lower than the Northern Hemisphere value of ∼0.2. The (236)U inventory of (8.4 ± 0.3) × 10(11) at/m(2) was more than an order of magnitude lower than values reported for the Northern Hemisphere. The (239)Pu activity concentrations are in excellent agreement with a previous study and the (239+240)Pu inventory was (13.85 ± 0.29) Bq/m(2). The weighted mean (240)Pu/(239)Pu isotopic ratio of 0.142 ± 0.005 is slightly lower than the value for global fallout, but our results are consistent with the average ratio of 0.173 ± 0.027 for the southern equatorial region (0-30°S). Copyright © 2014 Elsevier Ltd. All rights reserved.

Azimuthal anisotropy in U+U collisions at STAR

DOE PAGES

Wang, Hui; Sorensen, Paul

2014-10-06

The azimuthal anisotropy of particle production is commonly used in high-energy nuclear collisions to study the early evolution of the expanding system. The prolate shape of uranium nuclei makes it possible to study how the geometry of the colliding nuclei affects final state anisotropies. It also provides a unique opportunity to understand how entropy is produced in heavy ion collisions. In this paper, the two- and four- particle cumulant v 2 (v 2{2} and v 2{4}) from U+U collisions at √ sNN = 193 GeV and Au+Au collisions at √ sNN = 200 GeV for inclusive charged hadrons will bemore » presented. The STAR Zero Degree Calorimeters are used to select very central collisions. Differences were observed between the multiplicity dependence of v 2{2} for most central Au+Au and U+U collisions. The multiplicity dependence of v 2{2} in central collisions were compared to Monte Carlo Glauber model predictions and it was seen that this model cannot explain the present results. (auth)« less

Hyaluronan inhibits prostaglandin E2 production via CD44 in U937 human macrophages.

PubMed

Yasuda, Tadashi

2010-03-01

Prostaglandin E(2) (PGE(2)) is one of the key mediators of inflammation in affected joints of rheumatoid arthritis (RA). Intra-articular injection of high molecular weight hyaluronan (HA) into RA knee joints relieves arthritic pain. Although HA has been shown to inhibit PGE(2) production in cytokine-stimulated synovial fibroblasts, it remains unclear how HA suppresses PGE(2) production in activated cells. Furthermore, HA effect on macrophages has rarely been investigated in spite of their contribution to RA joint pathology. This study was aimed to investigate the inhibitory mechanism of HA on lipopolysaccharide (LPS)-stimulated PGE(2) production in U937 human macrophages. Stimulation of U937 macrophages with LPS enhanced PGE(2) production in association with increased protein levels of cyclooxygenase-2 (COX-2). Pretreatment with HA of 2,700 kDa resulted in suppression of the LPS-mediated induction of COX-2, leading to a decrease in PGE(2) production. Likewise, the LPS-stimulated PGE(2) production was inhibited by the pretreatment with a specific COX2 inhibitor, NS-398, or a specific inhibitor of nuclear factor (NF)-kappaB, BAY11-7085. HA also decreased the degree of phosphorylation and nuclear translocation of NF-kappaB enhanced by LPS. Fluorescence cytochemistry demonstrated that HA bound to CD44, the principal HA receptor, on U937 macrophages. Anti-CD44 antibody reversed the inhibitory effects of HA on the LPS-mediated increase in PGE(2) production, COX-2 induction, and activation of NF-kappaB. These results indicate that HA suppresses the LPS-stimulated PGE(2) production via CD44 through down-regulation of NF-kappaB. Administration of HA into RA joints may decrease PGE(2) production by activated macrophages, which could result in improvement of arthritic pain.

Effect of hypoxia on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells.

PubMed

Minchenko, O H; Riabovol, O O; Tsymbal, D O; Minchenko, D O; Ratushna, O O

2016-01-01

We have studied the effect of hypoxia on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells under the inhibition of IRE1 (inositol requiring enzyme-1), which controls cell proliferation and tumor growth as a central mediator of endoplasmic reticulum stress. It was shown that hypoxia down-regulated gene expression of malate dehydrogenase 2 (MDH2), malic enzyme 2 (ME2), mitochondrial aspartate aminotransferase (GOT2), and subunit B of succinate dehydrogenase (SDHB) in control (transfected by empty vector) glioma cells in a gene specific manner. At the same time, the expression level of mitochondrial NADP+-dependent isocitrate dehydrogenase 2 (IDH2) and subunit D of succinate dehydrogenase (SDHD) genes in these cells does not significantly change in hypoxic conditions. It was also shown that the inhibition of ІRE1 signaling enzyme function in U87 glioma cells decreases the effect of hypoxia on the expression of ME2, GOT2, and SDHB genes and introduces the sensitivity of IDH2 gene to hypoxia. Furthermore, the expression of all studied genes depends on IRE1-mediated endoplasmic reticulum stress signaling in gene specific manner, because ІRE1 knockdown significantly decreases their expression in normoxic conditions, except for IDH2 gene, which expression level is strongly up-regulated. Therefore, changes in the expression level of nuclear genes encoding ME2, MDH2, IDH2, SDHB, SDHD, and GOT2 proteins possibly reflect metabolic reprogramming of mitochondria by hypoxia and IRE1-mediated endoplasmic reticulum stress signaling and correlate with suppression of glioma cell proliferation under inhibition of the IRE1 enzyme function.

33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill...

33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill...

33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill...

33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill...

33 CFR 334.830 - Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill. 334.830 Section 334.830 Navigation and Navigable... REGULATIONS § 334.830 Lake Michigan; small-arms range adjacent to U.S. Naval Training Center, Great Lakes, Ill...

Kelch-like ECH-associated Protein 1-dependent Nuclear Factor-E2-related Factor 2 Activation in Relation to Antioxidation Induced by Sevoflurane Preconditioning.

PubMed

Cai, Min; Tong, Li; Dong, Beibei; Hou, Wugang; Shi, Likai; Dong, Hailong

2017-03-01

The authors have reported that antioxidative effects play a crucial role in the volatile anesthetic-induced neuroprotection. Accumulated evidence shows that endogenous antioxidation could be up-regulated by nuclear factor-E2-related factor 2 through multiple pathways. However, whether nuclear factor-E2-related factor 2 activation is modulated by sevoflurane preconditioning and, if so, what is the signaling cascade underlying upstream of this activation are still unknown. Sevoflurane preconditioning in mice was performed with sevoflurane (2.5%) 1 h per day for five consecutive days. Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. Expression of nuclear factor-E2-related factor 2, kelch-like ECH-associated protein 1, manganese superoxide dismutase, thioredoxin-1, and nicotinamide adenine dinucleotide phosphate quinolone oxidoreductase-1 was detected (n = 6). The antioxidant activities and oxidative product expression were also examined. To determine the role of kelch-like ECH-associated protein 1 inhibition-dependent nuclear factor-E2-related factor 2 activation in sevoflurane preconditioning-induced neuroprotection, the kelch-like ECH-associated protein 1-nuclear factor-E2-related factor 2 signal was modulated by nuclear factor-E2-related factor 2 knockout, kelch-like ECH-associated protein 1 overexpression lentivirus, and kelch-like ECH-associated protein 1 deficiency small interfering RNA (n = 8). The infarct volume, neurologic scores, and cellular apoptosis were assessed. Sevoflurane preconditioning elicited neuroprotection and increased nuclear factor-E2-related factor 2 nuclear translocation, which in turn up-regulated endogenous antioxidation and reduced oxidative injury. Sevoflurane preconditioning reduced kelch-like ECH-associated protein 1 expression. Nuclear factor-E2-related factor 2 ablation abolished neuroprotection and reversed sevoflurane preconditioning by mediating the up-regulation of antioxidants. Kelch

Comparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise

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

Rondahl, Stina Holmgren; Pointurier, Fabien; Ahlinder, Linnea

This work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear forensic round-robin exercise. In this work powder X-ray diffraction (p-XRD) is regarded as the reference technique. Neutron diffraction produced a superior high-angle diffraction pattern relative to p-XRD. Requiring only small amounts of sample, µ-Raman spectroscopy was used for the first time in this context as a potentially complementary technique to p-XRD. The chemical phases were identified as pure UO 2 in two materials, and as a mixture of UO 2, U 3O 8 and an intermediate species U 3Omore » 7 in the third material.« less

Comparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise

DOE PAGES

Rondahl, Stina Holmgren; Pointurier, Fabien; Ahlinder, Linnea; ...

2018-01-24

This work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear forensic round-robin exercise. In this work powder X-ray diffraction (p-XRD) is regarded as the reference technique. Neutron diffraction produced a superior high-angle diffraction pattern relative to p-XRD. Requiring only small amounts of sample, µ-Raman spectroscopy was used for the first time in this context as a potentially complementary technique to p-XRD. The chemical phases were identified as pure UO 2 in two materials, and as a mixture of UO 2, U 3O 8 and an intermediate species U 3Omore » 7 in the third material.« less

Comparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise.

PubMed

Rondahl, Stina Holmgren; Pointurier, Fabien; Ahlinder, Linnea; Ramebäck, Henrik; Marie, Olivier; Ravat, Brice; Delaunay, François; Young, Emma; Blagojevic, Ned; Hester, James R; Thorogood, Gordon; Nelwamondo, Aubrey N; Ntsoane, Tshepo P; Roberts, Sarah K; Holliday, Kiel S

2018-01-01

This work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear forensic round-robin exercise. In this work powder X-ray diffraction (p-XRD) is regarded as the reference technique. Neutron diffraction produced a superior high-angle diffraction pattern relative to p-XRD. Requiring only small amounts of sample, µ-Raman spectroscopy was used for the first time in this context as a potentially complementary technique to p-XRD. The chemical phases were identified as pure UO 2 in two materials, and as a mixture of UO 2 , U 3 O 8 and an intermediate species U 3 O 7 in the third material.

Box C/D small nucleolar RNA (snoRNA) U60 regulates intracellular cholesterol trafficking.

PubMed

Brandis, Katrina A; Gale, Sarah; Jinn, Sarah; Langmade, Stephen J; Dudley-Rucker, Nicole; Jiang, Hui; Sidhu, Rohini; Ren, Aileen; Goldberg, Anna; Schaffer, Jean E; Ory, Daniel S

2013-12-13

Mobilization of plasma membrane (PM) cholesterol to the endoplasmic reticulum is essential for cellular cholesterol homeostasis. The mechanisms regulating this retrograde, intermembrane cholesterol transfer are not well understood. Because mutant cells with defects in PM to endoplasmic reticulum cholesterol trafficking can be isolated on the basis of resistance to amphotericin B, we conducted an amphotericin B loss-of-function screen in Chinese hamster ovary (CHO) cells using insertional mutagenesis to identify genes that regulate this trafficking mechanism. Mutant line A1 displayed reduced cholesteryl ester formation from PM-derived cholesterol and increased de novo cholesterol synthesis, indicating a deficiency in retrograde cholesterol transport. Genotypic analysis revealed that the A1 cell line contained one disrupted allele of the U60 small nucleolar RNA (snoRNA) host gene, resulting in haploinsufficiency of the box C/D snoRNA U60. Complementation and mutational studies revealed the U60 snoRNA to be the essential feature from this locus that affects cholesterol trafficking. Lack of alteration in predicted U60-mediated site-directed methylation of 28 S rRNA in the A1 mutant suggests that the U60 snoRNA modulates cholesterol trafficking by a mechanism that is independent of this canonical function. Our study adds to a growing body of evidence for participation of small noncoding RNAs in cholesterol homeostasis and is the first to implicate a snoRNA in this cellular function.

Tracing nuclear elements released by Fukushima Nuclear Power Plant accident

NASA Astrophysics Data System (ADS)

Tsujimura, M.; Onda, Y.; Abe, Y.; Hada, M.; Pun, I.

2011-12-01

Radioactive contamination has been detected in Fukushima and the neighboring regions due to the nuclear accident at Fukushima Daiichi Nuclear Power Plant (NPP) following the earthquake and tsunami occurred on 11th March 2011. The small experimental catchments have been established in Yamakiya district, Kawamata Town, Fukushima Prefecture, located approximately 35 km west from the Fukushima NPP. The tritium (3H) concentration and stable isotopic compositions of deuterium and oxygen-18 have been determined on the water samples of precipitation, soil water at the depths of 10 to 30 cm, groundwater at the depths of 5 m to 50 m, spring water and stream water taken at the watersheds in the recharge and discharge zones from the view point of the groundwater flow system. The tritium concentration of the rain water fell just a few days after the earthquake showed a value of approximately 17 Tritium Unit (T.U.), whereas the average concentration of the tritium in the precipitation was less than 5 T.U. before the Fukushima accident. The spring water in the recharge zone showed a relatively high tritium concentration of approximately 12 T.U., whereas that of the discharge zone showed less than 5 T.U. Thus, the artificial tritium was apparently injected in the groundwater flow system due to the Fukushima NPP accident, whereas that has not reached at the discharge zone yet. The monitoring of the nuclear elements is now on going from the view points of the hydrological cycles and the drinking water security.

Partially-reflected water-moderated square-piteched U(6.90)O 2 fuel rod lattices with 0.67 fuel to water volume ratio (0.800 CM Pitch)

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

Harms, Gary A.

The US Department of Energy (DOE) Nuclear Energy Research Initiative funded the design and construction of the Seven Percent Critical Experiment (7uPCX) at Sandia National Laboratories. The start-up of the experiment facility and the execution of the experiments described here were funded by the DOE Nuclear Criticality Safety Program. The 7uPCX is designed to investigate critical systems with fuel for light water reactors in the enrichment range above 5% 235U. The 7uPCX assembly is a water-moderated and -reflected array of aluminum-clad square-pitched U(6.90%)O 2 fuel rods.

Assessment of nuclear reactor concepts for low power space applications

NASA Technical Reports Server (NTRS)

Klein, Andrew C.; Gedeon, Stephen R.; Morey, Dennis C.

1988-01-01

The results of a preliminary small reactor concepts feasibility and safety evaluation designed to provide a first order validation of the nuclear feasibility and safety of six small reactor concepts are given. These small reactor concepts have potential space applications for missions in the 1 to 20 kWe power output range. It was concluded that low power concepts are available from the U.S. nuclear industry that have the potential for meeting both the operational and launch safety space mission requirements. However, each design has its uncertainties, and further work is required. The reactor concepts must be mated to a power conversion technology that can offer safe and reliable operation.

Incorporation mechanisms of actinide elements into the structures of U 6+ phases formed during the oxidation of spent nuclear fuel

NASA Astrophysics Data System (ADS)

Burns, Peter C.; Ewing, Rodney C.; Miller, Mark L.

1997-05-01

Uranyl oxide hydrate and uranyl silicate phases will form due to the corrosion and alteration of spent nuclear fuel under oxidizing conditions in silica-bearing solution. The actinide elements in the spent fuel may be incorporated into the structures of these secondary U6+ phases during the long-term corrosion of the UO 2 in spent fuel. The incorporation of actinide elements into the crystal structures of the alteration products may decrease actinide mobility. The crystal chemistry of the various oxidation states of the actinide elements of environmental concern is examined to identify possible incorporation mechanisms. The substitutions Pu 6+U 6+ and (Pu 5+, Np 5+)U 6+ should readily occur in many U 6+ structures, although structural modification may be required to satisfy local bond-valence requirements. Crystal-chemical characteristics of the U 6+ phases indicate that An 4+ (An: actinide)U 6+ substitution is likely to occur in the sheets of uranyl polyhedra that occur in the structures of the minerals schoepite, [(UO 2) 8O 2(OH) 12](H 2O) 12, ianthinite, [U 24+ (UO 2) 4O 6(OH) 4(H 2O) 4](H 2O) 5, becquerelite, Ca[(UO 2) 3O 2(OH) 3] 2(H 2O) 8, compreignacite, K 2[(UO 2) 3O 2(OH) 3] 2(H 2O) 8, α-uranophane, Ca[(UO 2)(SiO 3OH)] 2(H 2O) 5, and boltwoodite, K(H 2O)[(UO 2)(SiO 4)], all of which are likely to form due to the oxidation and alteration of the UO 2 in spent fuel. The incorporation of An 3+ into the sheets of the structures of α-uranophane and boltwoodite, as well as interlayer sites of various uranyl phases, may occur.

Lamping process and application of ultra small U-shaped, whispery gallery mode (WGM) based optic fiber sensors

NASA Astrophysics Data System (ADS)

Chang, Yuan Cheng; Chiang, Chia Chin

2015-07-01

This study success to smaller and control the diameter of single mode optical fiber whispery gallery mode (WGM) to diameter 0.8 mm nonetching and nontaping treated. The sensitivity of this type ultra-small U-shape WGM strengthens neither etching nor taping fibre. The sensitivity we apply to thermo test depends on wavelength shift from 40 ~ 96°C (R2 = 0.99 ). The specially characteristics of the optical fiber could be tested for temperature, refraction, vibration, concussion, and CO2 detection.

Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Schnitzler, Bruce G.; Borowski, Stanley K.

2012-01-01

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified as the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine operations and the engine and stage design were

Separation of uranium from (U, Th)O 2 and (U, Pu)O 2 by solid state reactions route

NASA Astrophysics Data System (ADS)

Keskar, Meera; Mudher, K. D. Singh; Venugopal, V.

2005-01-01

Solid state reactions of UO 2, ThO 2, PuO 2 and their mixed oxides (U, Th)O 2 and (U, Pu)O 2 were carried out with sodium nitrate upto 900 °C, to study the formation of various phases at different temperatures, which are amenable for easy dissolution and separation of the actinide elements in dilute acid. Products formed by reacting unsintered as well as sintered UO 2 with NaNO 3 above 500 °C were readily soluble in 2 M HNO 3, whereas ThO 2 and PuO 2 did not react with NaNO 3 to form any soluble products. Thus reactions of mixed oxides (U, Th)O 2 and (U, Pu)O 2 with NaNO 3 were carried out to study the quantitative separation of U from (U, Th)O 2 and (U, Pu)O 2. X-ray diffraction, X-ray fluorescence, thermal analysis and chemical analysis techniques were used for the characterization of the products formed during the reactions.

Progression through the spliceosome cycle requires Prp38p function for U4/U6 snRNA dissociation.

PubMed Central

Xie, J; Beickman, K; Otte, E; Rymond, B C

1998-01-01

The elaborate and energy-intensive spliceosome assembly pathway belies the seemingly simple chemistry of pre-mRNA splicing. Prp38p was previously identified as a protein required in vivo and in vitro for the first pre-mRNA cleavage reaction catalyzed by the spliceosome. Here we show that Prp38p is a unique component of the U4/U6.U5 tri-small nuclear ribonucleoprotein (snRNP) particle and is necessary for an essential step late in spliceosome maturation. Without Prp38p activity spliceosomes form, but arrest in a catalytically impaired state. Functional spliceosomes shed U4 snRNA before 5' splice-site cleavage. In contrast, Prp38p-defective spliceosomes retain U4 snRNA bound to its U6 snRNA base-pairing partner. Prp38p is the first tri-snRNP-specific protein shown to be dispensable for assembly, but required for conformational changes which lead to catalytic activation of the spliceosome. PMID:9582287

Multi-tasking Sulf1/Sulf2 enzymes do not only facilitate extracellular cell signalling but also participate in cell cycle related nuclear events.

PubMed

Krishnakumar, Kavithanjali; Chakravorty, Ishani; Foy, Wendy; Allen, Steve; Justo, Tiago; Mukherjee, Abir; Dhoot, Gurtej K

2018-03-01

This study demonstrates highly dynamic spatial and temporal pattern of SULF1/SULF2 expression in a number of neuronal cell types growing in normal culture medium that included their transient nuclear mobilisation. Their nuclear translocation became particularly apparent during cell proliferation as both SULF1/SULF2 demonstrated not only cell membrane associated expression, their known site of function but also transient nuclear mobilisation during nuclear cell division. Nuclear localisation was apparent not only by immunocytochemical staining but also confirmed by immunoblotting staining of isolated nuclear fractions of C6, U87 and N2A cells. Immunocytochemical analysis demonstrated rapid nuclear exit of both SULF1/SULF2 following cell division that was slightly delayed but not blocked in a fraction of the polyploid cells observed in C6 cells. The overexpression of both Sulf1 and Sulf2 genes in C6 and U87 cells markedly promoted in vitro growth of these cells accompanied by nuclear mobilisation while inhibition of both these genes inhibited cell proliferation with little or no nuclear SULF1/SULF2 mobilisation. SULF1/SULF2 activity in these cells thus demonstrated a clear co-ordination of extracellular cell signalling with nuclear events related to cell proliferation. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

(236)U and (239,)(240)Pu ratios from soils around an Australian nuclear weapons test site.

PubMed

Tims, S G; Froehlich, M B; Fifield, L K; Wallner, A; De Cesare, M

2016-01-01

The isotopes (236)U, (239)Pu and (240)Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes potentially constitute artificial tracers of recent soil erosion and sediment movement. Only Accelerator Mass Spectrometry has the requisite sensitivity to measure all three isotopes at these environmental levels. Coupled with its relatively high throughput capabilities, this makes it feasible to conduct studies of erosion across the geographical extent of the Australian continent. In the Australian context, however, global fallout is not the only source of these isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The tests have made a significant contribution to the Pu isotopic abundances present in the region around Maralinga and out to distances ∼1000 km, and impact on the assessment techniques used in the soil and sediment tracer studies. Quantification of the relative fallout contribution derived from detonations at Maralinga is complicated owing to significant contamination around the test site from numerous nuclear weapons safety trials that were also carried out around the site. We show that (236)U can provide new information on the component of the fallout that is derived from the local nuclear weapons tests, and highlight the potential of (236)U as a new fallout tracer. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

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.

Helicity Evolution at Small x

NASA Astrophysics Data System (ADS)

Sievert, Michael; Kovchegov, Yuri; Pitonyak, Daniel

2017-01-01

We construct small- x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g1 structure function. These evolution equations resum powers of ln2(1 / x) in the polarization-dependent evolution along with the powers of ln(1 / x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-Nc and large-Nc &Nf limits. After solving the large-Nc equations numerically we obtain the following small- x asymptotics for the flavor-singlet g1 structure function along with quarks hPDFs and helicity TMDs (in absence of saturation effects): g1S(x ,Q2) ΔqS(x ,Q2) g1L S(x ,kT2) (1/x) > αh (1/x) 2.31√{αsNc/2 π. We also give an estimate of how much of the proton's spin may be at small x and what impact this has on the so-called ``spin crisis.'' Work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Award Number DE-SC0004286 (YK), the RIKEN BNL Research Center, and TMD Collaboration (DP), and DOE Contract No. DE-SC0012704 (MS).

78 FR 13712 - U.S. Nuclear Regulatory Commission Planned Monitoring Activities for F-Area Tank Farm at the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-28

... Monitoring Activities for F-Area Tank Farm at the Savannah River Site, Revision 0 AGENCY: Nuclear Regulatory... carrying out its responsibilities for monitoring DOE's waste disposal activities at the F-Area Tank Farm at... the availability of ``U.S. Nuclear Regulatory Commission Plan for Monitoring Disposal Actions Taken by...

Stopping relativistic Xe, Ho, Au, and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly changed particles, for which the first Born approximation is not valid.

Stopping relativistic Xe, Ho, Au and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly charged particles, for which the first Born approximation is not valid.

Direct Compositional Characterization of (U,Th)O2 Powders, Microspheres, and Pellets Using TXRF.

PubMed

Dhara, Sangita; Prabhat, Parimal; Misra, N L

2015-10-20

A total reflection X-ray fluorescence (TXRF) analysis method for direct compositional characterization of sintered and green (U,Th)O2 samples in different forms (e.g., pellets, powders, and microspheres) without sample dissolution has been developed for the first time. The methodology involves transfer of only a few nanograms of the sample on the TXRF sample support by gently rubbing the samples on supports or taking their tiny uniform slurry in collodion on the sample support, drying them to make thin film, and measuring the TXRF spectra of the specimens thus prepared. This approach minimizes the matrix effects. Uranium determinations from the TXRF spectra of such specimens were made with respect to thorium, considering it as an internal standard. Samples having uranium atom percent (at%) from 0 to 100 in (U,Th)O2 were analyzed for uranium in comparison to thorium. The results showed an average precision of 2.6% (RSD, 2σ, n = 8). The TXRF-determined results deviated from expected values within 5%. The TXRF results were compared with those of biamperometry with good agreement. The lattice parameters of the solid solutions were calculated using their XRD patterns. A good correlation between lattice parameters and TXRF-determined U at% and between TXRF-determined U at% and expected U at%, calculated on the basis of preparation of (U,Th)O2 solid solutions, was obtained. The developed method is capable of analyzing (U,Th)O2 samples directly with almost negligible sample preparation and is well suited for radioactive samples. The present study suggests that this method can be extended for the determination of U,Th and Pu in other nuclear fuel materials (e.g., nitrides, carbides, etc.) in the form of pellets, powders, and microspheres after suitable modifications in sample handling procedure.

Archival and Dissemination of the U.S. and Canadian Experimental Nuclear Reaction Data (EXFOR Project)

NASA Astrophysics Data System (ADS)

Pritychenko, Boris; Hlavac, Stanislav; Schwerer, Otto; Zerkin, Viktor

2017-09-01

The Exchange Format (EXFOR) or experimental nuclear reaction database and the associated Web interface provide access to the wealth of low- and intermediate-energy nuclear reaction physics data. This resource includes numerical data sets and bibliographical information for more than 22,000 experiments since the beginning of nuclear science. Analysis of the experimental data sets, recovery and archiving will be discussed. Examples of the recent developments of the data renormalization, uploads and inverse reaction calculations for nuclear science and technology applications will be presented. The EXFOR database, updated monthly, provides an essential support for nuclear data evaluation, application development and research activities. It is publicly available at the National Nuclear Data Center website http://www.nndc.bnl.gov/exfor and the International Atomic Energy Agency mirror site http://www-nds.iaea.org/exfor. This work was sponsored in part by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 with Brookha ven Science Associates, LLC.

Solid state reactions of CeO 2, PuO 2, (U,Ce)O 2 and (U,Pu)O 2 with K 2S 2O 8

NASA Astrophysics Data System (ADS)

Keskar, Meera; Kasar, U. M.; Mudher, K. D. Singh; Venugopal, V.

2004-09-01

Solid state reactions of CeO 2, PuO 2 and mixed oxides (U,Ce)O 2 and (U,Pu)O 2 containing different mol.% of Ce and Pu, were carried out with K 2S 2O 8 at different temperatures to identify the formation of various products and to investigate their dissolution behaviour. X-ray, chemical and thermal analysis methods were used to characterise the products formed at various temperatures. The products obtained by heating two moles of K 2S 2O 8 with one mole each of CeO 2, PuO 2, (U,Ce)O 2 and (U,Pu)O 2 at 400 °C were identified as K 4Ce(SO 4) 4, K 4Pu(SO 4) 4, K 4(U,Ce)(SO 4) 4 and K 4(U,Pu)(SO 4) 4, respectively. K 4Ce(SO 4) 4 further decomposed to form K 4Ce(SO 4) 3.5 at 600 °C and mixture of K 2SO 4 and CeO 2 at 950 °C. Thus the products formed during the reaction of 2K 2S 2O 8 + CeO 2 show that cerium undergoes changes in oxidation state from +4 to +3 and again to +4. XRD data of K 4Ce(SO 4) 4 and K 4Ce(SO 4) 3.5 were indexed on triclinic and monoclinic system, respectively. PuO 2 + 2K 2S 2O 8 reacts at 400 °C to form K 4Pu(SO 4) 4 which was stable upto 750 °C and further decomposes to form K 2SO 4 + PuO 2 at 1000 °C. The products formed at 400 °C during the reactions of the oxides and mixed oxides were found to be readily soluble in 1-2 M HNO 3.

North Korea’s Second Nuclear Test: Implications of U.N. Security Council Resolution 1874

DTIC Science & Technology

2010-04-15

butter” (or in North Korea’s case, rice ) and, in the process, creating a humanitarian disaster. The additional sanctions in U.N. Resolution 1874 target...the May 2009 North Korean nuclear test. See also CRS Report RL34327, Proliferation Security Initiative (PSI), by Mary Beth Nikitin. 72 “Nuclear Black ...Beverages 5,137,988 5,084,449 6,652,041 33 Perfumery, Cosmetic Products 1,322,454 1,672,327 1,688,481 42 Leather Art; Saddlery, Etc. 772,645 1,441,805

Lower neurocognitive function in U-2 pilots

PubMed Central

Tate, David F.; Wood, Joe; Sladky, John H.; McDonald, Kent; Sherman, Paul M.; Kawano, Elaine S.; Rowland, Laura M.; Patel, Beenish; Wright, Susan N.; Hong, Elliot; Rasmussen, Jennifer; Willis, Adam M.; Kochunov, Peter V.

2014-01-01

Objective: Determine whether United States Air Force (USAF) U-2 pilots (U2Ps) with occupational exposure to repeated hypobaria had lower neurocognitive performance compared to pilots without repeated hypobaric exposure and whether U2P neurocognitive performance correlated with white matter hyperintensity (WMH) burden. Methods: We collected Multidimensional Aptitude Battery–II (MAB-II) and MicroCog: Assessment of Cognitive Functioning (MicroCog) neurocognitive data on USAF U2Ps with a history of repeated occupational exposure to hypobaria and compared these with control data collected from USAF pilots (AFPs) without repeated hypobaric exposure (U2Ps/AFPs MAB-II 87/83; MicroCog 93/80). Additional comparisons were performed between U2Ps with high vs low WMH burden. Results: U2Ps with repeated hypobaric exposure had significantly lower scores than control pilots on reasoning/calculation (U2Ps/AFPs 99.4/106.5), memory (105.5/110.9), information processing accuracy (102.1/105.8), and general cognitive functioning (103.5/108.5). In addition, U2Ps with high whole-brain WMH count showed significantly lower scores on reasoning/calculation (high/low 96.8/104.1), memory (102.9/110.2), general cognitive functioning (101.5/107.2), and general cognitive proficiency (103.6/108.8) than U2Ps with low WMH burden (high/low WMH mean volume 0.213/0.003 cm3 and mean count 14.2/0.4). Conclusion: In these otherwise healthy, highly functioning individuals, pilots with occupational exposure to repeated hypobaria demonstrated lower neurocognitive performance, albeit demonstrable on only some tests, than pilots without repeated exposure. Furthermore, within the U2P population, higher WMH burden was associated with lower neurocognitive test performance. Hypobaric exposure may be a risk factor for subtle changes in neurocognition. PMID:25008397

78 FR 45969 - Trade Barriers That U.S. Small and Medium-Sized Enterprises Perceive as Affecting Exports to the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

... INTERNATIONAL TRADE COMMISSION [Investigation No. 332-541] Trade Barriers That U.S. Small and... Investigation and Scheduling of Hearing AGENCY: United States International Trade Commission. ACTION... 332(g) of the Tariff Act of 1930 (19 U.S.C. 1332(g)), the U.S. International Trade Commission...

Genome-wide RNA-binding analysis of the trypanosome U1 snRNP proteins U1C and U1-70K reveals cis/trans-spliceosomal network

PubMed Central

Preußer, Christian; Rossbach, Oliver; Hung, Lee-Hsueh; Li, Dan; Bindereif, Albrecht

2014-01-01

Trans-splicing in trypanosomes adds a 39-nucleotide mini-exon from the spliced leader (SL) RNA to the 5′ end of each protein-coding sequence. On the other hand, cis-splicing of the few intron-containing genes requires the U1 small nuclear ribonucleoprotein (snRNP) particle. To search for potential new functions of the U1 snRNP in Trypanosoma brucei, we applied genome-wide individual-nucleotide resolution crosslinking-immunoprecipitation (iCLIP), focusing on the U1 snRNP-specific proteins U1C and U1-70K. Surprisingly, U1C and U1-70K interact not only with the U1, but also with U6 and SL RNAs. In addition, mapping of crosslinks to the cis-spliced PAP [poly(A) polymerase] pre-mRNA indicate an active role of these proteins in 5′ splice site recognition. In sum, our results demonstrate that the iCLIP approach provides insight into stable and transient RNA–protein contacts within the spliceosomal network. We propose that the U1 snRNP may represent an evolutionary link between the cis- and trans-splicing machineries, playing a dual role in 5′ splice site recognition on the trans-spliceosomal SL RNP as well as on pre-mRNA cis-introns. PMID:24748659

Expert judgments about RD&D and the future of nuclear energy.

PubMed

Anadón, Laura D; Bosetti, Valentina; Bunn, Matthew; Catenacci, Michela; Lee, Audrey

2012-11-06

Probabilistic estimates of the cost and performance of future nuclear energy systems under different scenarios of government research, development, and demonstration (RD&D) spending were obtained from 30 U.S. and 30 European nuclear technology experts. We used a novel elicitation approach which combined individual and group elicitation. With no change from current RD&D funding levels, experts on average expected current (Gen. III/III+) designs to be somewhat more expensive in 2030 than they were in 2010, and they expected the next generation of designs (Gen. IV) to be more expensive still as of 2030. Projected costs of proposed small modular reactors (SMRs) were similar to those of Gen. IV systems. The experts almost unanimously recommended large increases in government support for nuclear RD&D (generally 2-3 times current spending). The majority expected that such RD&D would have only a modest effect on cost, but would improve performance in other areas, such as safety, waste management, and uranium resource utilization. The U.S. and E.U. experts were in relative agreement regarding how government RD&D funds should be allocated, placing particular focus on very high temperature reactors, sodium-cooled fast reactors, fuels and materials, and fuel cycle technologies.

Substrate-assisted mechanism of RNP disruption by the spliceosomal Brr2 RNA helicase

PubMed Central

Theuser, Matthias; Höbartner, Claudia; Wahl, Markus C.; Santos, Karine F.

2016-01-01

The Brr2 RNA helicase disrupts the U4/U6 di-small nuclear RNA–protein complex (di-snRNP) during spliceosome activation via ATP-driven translocation on the U4 snRNA strand. However, it is unclear how bound proteins influence U4/U6 unwinding, which regions of the U4/U6 duplex the helicase actively unwinds, and whether U4/U6 components are released as individual molecules or as subcomplexes. Here, we set up a recombinant Brr2-mediated U4/U6 di-snRNP disruption system, showing that sequential addition of the U4/U6 proteins small nuclear ribonucleoprotein-associated protein 1 (Snu13), pre-mRNA processing factor 31 (Prp31), and Prp3 to U4/U6 di-snRNA leads to a stepwise decrease of Brr2-mediated U4/U6 unwinding, but that unwinding is largely restored by a Brr2 cofactor, the C-terminal Jab1/MPN domain of the Prp8 protein. Brr2-mediated U4/U6 unwinding was strongly inhibited by mutations in U4/U6 di-snRNAs that diminish the ability of U6 snRNA to adopt an alternative conformation but leave the number and kind of U4/U6 base pairs unchanged. Irrespective of the presence of the cofactor, the helicase segregated a Prp3-Prp31-Snu13-U4/U6 RNP into an intact Prp31-Snu13-U4 snRNA particle, free Prp3, and free U6 snRNA. Together, these observations suggest that Brr2 translocates only a limited distance on the U4 snRNA strand and does not actively release RNA-bound proteins. Unwinding is then completed by the partially displaced U6 snRNA adopting an alternative conformation, which leads to dismantling of the Prp3-binding site on U4/U6 di-snRNA but leaves the Prp31- and Snu13-binding sites on U4 snRNA unaffected. In this fashion, Brr2 can activate the spliceosome by stripping U6 snRNA of all precatalytic binding partners, while minimizing logistic requirements for U4/U6 di-snRNP reassembly after splicing. PMID:27354531

Calculations of atomic magnetic nuclear shielding constants based on the two-component normalized elimination of the small component method

NASA Astrophysics Data System (ADS)

Yoshizawa, Terutaka; Zou, Wenli; Cremer, Dieter

2017-04-01

A new method for calculating nuclear magnetic resonance shielding constants of relativistic atoms based on the two-component (2c), spin-orbit coupling including Dirac-exact NESC (Normalized Elimination of the Small Component) approach is developed where each term of the diamagnetic and paramagnetic contribution to the isotropic shielding constant σi s o is expressed in terms of analytical energy derivatives with regard to the magnetic field B and the nuclear magnetic moment 𝝁 . The picture change caused by renormalization of the wave function is correctly described. 2c-NESC/HF (Hartree-Fock) results for the σiso values of 13 atoms with a closed shell ground state reveal a deviation from 4c-DHF (Dirac-HF) values by 0.01%-0.76%. Since the 2-electron part is effectively calculated using a modified screened nuclear shielding approach, the calculation is efficient and based on a series of matrix manipulations scaling with (2M)3 (M: number of basis functions).

Comparison of Radiation Dose Studies of the 2011 Fukushima Nuclear Accident Prepared by the World Health Organization and the U.S. Department of Defense

DTIC Science & Technology

2012-11-01

R T Comparison of Radiation Dose Studies of the 2011 Fukushima Nuclear Accident Prepared by the World Health Organization and the U.S. Department...AND SUBTITLE Comparison of Radiation Dose Studies of the 2011 Fukushima Nuclear Accident Prepared by the World Health Organization and the U.S...in Japan on March 11, 2011 led to releases of radioactive materials from the Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Station

Presentation of Fukushima Analyses to U.S. Nuclear Power Plant Simulator Operators and Vendors

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

Osborn, Douglas; Kalinich, Donald A.; Cardoni, Jeffrey N

This document provides Sandia National Laboratories’ meeting notes and presentations at the Society for Modeling and Simulation Power Plant Simulator conference in Jacksonville, FL. The conference was held January 26-28, 2015, and SNL was invited by the U.S. nuclear industry to present Fukushima modeling insights and lessons learned.

RNomics: an experimental approach that identifies 201 candidates for novel, small, non-messenger RNAs in mouse

PubMed Central

Hüttenhofer, Alexander; Kiefmann, Martin; Meier-Ewert, Sebastian; O’Brien, John; Lehrach, Hans; Bachellerie, Jean-Pierre; Brosius, Jürgen

2001-01-01

In mouse brain cDNA libraries generated from small RNA molecules we have identified a total of 201 different expressed RNA sequences potentially encoding novel small non-messenger RNA species (snmRNAs). Based on sequence and structural motifs, 113 of these RNAs can be assigned to the C/D box or H/ACA box subclass of small nucleolar RNAs (snoRNAs), known as guide RNAs for rRNA. While 30 RNAs represent mouse homologues of previously identified human C/D or H/ACA snoRNAs, 83 correspond to entirely novel snoRNAs. Among these, for the first time, we identified four C/D box snoRNAs and four H/ACA box snoRNAs predicted to direct modifications within U2, U4 or U6 small nuclear RNAs (snRNAs). Furthermore, 25 snoRNAs from either class lacked antisense elements for rRNAs or snRNAs. Therefore, additional snoRNA targets have to be considered. Surprisingly, six C/D box snoRNAs and one H/ACA box snoRNA were expressed exclusively in brain. Of the 88 RNAs not belonging to either snoRNA subclass, at least 26 are probably derived from truncated heterogeneous nuclear RNAs (hnRNAs) or mRNAs. Short interspersed repetitive elements (SINEs) are located on five RNA sequences and may represent rare examples of transcribed SINEs. The remaining RNA species could not as yet be assigned either to any snmRNA class or to a part of a larger hnRNA/mRNA. It is likely that at least some of the latter will represent novel, unclassified snmRNAs. PMID:11387227

Thermodynamic modelling of the C-U and B-U binary systems

NASA Astrophysics Data System (ADS)

Chevalier, P. Y.; Fischer, E.

2001-02-01

The thermodynamic modelling of the carbon-uranium (C-U) and boron-uranium (B-U) binary systems is being performed in the framework of the development of a thermodynamic database for nuclear materials, for increasing the basic knowledge of key phenomena which may occur in the event of a severe accident in a nuclear power plant. Applications are foreseen in the nuclear safety field to the physico-chemical interaction modelling, on the one hand the in-vessel core degradation producing the corium (fuel, zircaloy, steel, control rods) and on the other hand the ex-vessel molten corium-concrete interaction (MCCI). The key O-U-Zr ternary system, previously modelled, allows us to describe the first interaction of the fuel with zircaloy cladding. Then, the three binary systems Fe-U, Cr-U and Ni-U were modelled as a preliminary work for modelling the O-U-Zr-Fe-Cr-Ni multicomponent system, allowing us to introduce the steel components in the corium. In the existing database (TDBCR, thermodynamic data base for corium), Ag and In were introduced for modelling AIC (silver-indium-cadmium) control rods which are used in French pressurized water reactors (PWR). Elsewhere, B 4C is also used for control rods. That is why it was agreed to extend in the next years the database with two new components, B and C. Such a work needs the thermodynamic modelling of all the binary and pseudo-binary sub-systems resulting from the combination of B, B 2O 3 and C with the major components of TDBCR, O-U-Zr-Fe-Cr-Ni-Ag-In-Ba-La-Ru-Sr-Al-Ca-Mg-Si + Ar-H. The critical assessment of the very numerous experimental information available for the C-U and B-U binary systems was performed by using a classical optimization procedure and the Scientific Group Thermodata Europe (SGTE). New optimized Gibbs energy parameters are given, and comparisons between calculated and experimental equilibrium phase diagrams or thermodynamic properties are presented. The self-consistency obtained is quite satisfactory.

Evaluating the Cost, Safety, and Proliferation Risks of Small Floating Nuclear Reactors.

PubMed

Ford, Michael J; Abdulla, Ahmed; Morgan, M Granger

2017-11-01

It is hard to see how our energy system can be decarbonized if the world abandons nuclear power, but equally hard to introduce the technology in nonnuclear energy states. This is especially true in countries with limited technical, institutional, and regulatory capabilities, where safety and proliferation concerns are acute. Given the need to achieve serious emissions mitigation by mid-century, and the multidecadal effort required to develop robust nuclear governance institutions, we must look to other models that might facilitate nuclear plant deployment while mitigating the technology's risks. One such deployment paradigm is the build-own-operate-return model. Because returning small land-based reactors containing spent fuel is infeasible, we evaluate the cost, safety, and proliferation risks of a system in which small modular reactors are manufactured in a factory, and then deployed to a customer nation on a floating platform. This floating small modular reactor would be owned and operated by a single entity and returned unopened to the developed state for refueling. We developed a decision model that allows for a comparison of floating and land-based alternatives considering key International Atomic Energy Agency plant-siting criteria. Abandoning onsite refueling is beneficial, and floating reactors built in a central facility can potentially reduce the risk of cost overruns and the consequences of accidents. However, if the floating platform must be built to military-grade specifications, then the cost would be much higher than a land-based system. The analysis tool presented is flexible, and can assist planners in determining the scope of risks and uncertainty associated with different deployment options. © 2017 Society for Risk Analysis.

Strongly correlated electron behavior in single crystalline U2Os3Al9

NASA Astrophysics Data System (ADS)

Kumar, Neeraj; Das, Pranab Kumar; Kulkarni, Ruta; Thamizhavel, A.; Dhar, S. K.

2012-12-01

We report the magnetic properties of a single crystal of a new compound U2Os3Al9 which crystallizes in the well known Y2Co3Ga9 type orthorhombic structure with space group Cmcm. The susceptibility of U2Os3Al9 shows a peak at 7 K typical of antiferromagnetic ordering. The susceptibility in the paramagnetic state is anisotropic, the easy axis of magnetization lying in the ab-plane of the orthorhombic crystal lattice. The magnetization at 2 K, measured up to a maximum field of 160 kOe, shows a metamagnetic transition near 118 kOe when the field is aligned along [010] in addition to a small metamagnetic transition near 25 kOe. The bulk antiferromagnetic ordering of the uranium ions at TN = 7 K is confirmed by a peak in the heat capacity with ΔC nearly 7 J/U.mol K. An extrapolation of the heat capacity data from the paramagnetic regime to T = 0 gives an enhanced electronic specific heat coefficient of 120 mJ/U.mol K2. The electrical resistivity of U2Os3Al9 shows a negative temperature coefficient between 300 and TN which is a signature of spin fluctuations in a narrow band or a Kondo type of interaction. The data thus suggest the presence of strong electron correlations in this compound.

A roadmap for nuclear energy technology

NASA Astrophysics Data System (ADS)

Sofu, Tanju

2018-01-01

The prospects for the future use of nuclear energy worldwide can best be understood within the context of global population growth, urbanization, rising energy need and associated pollution concerns. As the world continues to urbanize, sustainable development challenges are expected to be concentrated in cities of the lower-middle-income countries where the pace of urbanization is fastest. As these countries continue their trajectory of economic development, their energy need will also outpace their population growth adding to the increased demand for electricity. OECD IEA's energy system deployment pathway foresees doubling of the current global nuclear capacity by 2050 to reduce the impact of rapid urbanization. The pending "retirement cliff" of the existing U.S. nuclear fleet, representing over 60 percent of the nation's emission-free electricity, also poses a large economic and environmental challenge. To meet the challenge, the U.S. DOE has developed the vision and strategy for development and deployment of advanced reactors. As part of that vision, the U.S. government pursues programs that aim to expand the use of nuclear power by supporting sustainability of the existing nuclear fleet, deploying new water-cooled large and small modular reactors to enable nuclear energy to help meet the energy security and climate change goals, conducting R&D for advanced reactor technologies with alternative coolants, and developing sustainable nuclear fuel cycle strategies. Since the current path relying heavily on water-cooled reactors and "once-through" fuel cycle is not sustainable, next generation nuclear energy systems under consideration aim for significant advances over existing and evolutionary water-cooled reactors. Among the spectrum of advanced reactor options, closed-fuel-cycle systems using reactors with fast-neutron spectrum to meet the sustainability goals offer the most attractive alternatives. However, unless the new public-private partnership models emerge

Impact Upon U.S. Security of a South African Nuclear Weapons Capability.

DTIC Science & Technology

1981-04-01

Simon Brand, dubbed the international companies as the " engine of growth" for the South African economy. The petroleum market, automobile industry , and...thereby halting the flow of metals key to high technology industries which in turn, are critical to U.S. national security. Should Washington’s...to produce nuclear weapons." * More specifically, we found that South Africa has: A sufficient scientific and industrial base on which to conduct

U, Pu, and Am nuclear signatures of the Thule hydrogen bomb debris.

PubMed

Eriksson, Mats; Lindahl, Patric; Roos, Per; Dahlgaard, Henning; Holm, Elis

2008-07-01

This study concerns an arctic marine environment that was contaminated by actinide elements after a nuclear accident in 1968, the so-called Thule accident In this study we have analyzed five isolated hot particles as well as sediment samples containing particles from the weapon material for the determination of the nuclear fingerprint of the accident. We report that the fissile material in the hydrogen weapons involved in the Thule accident was a mixture of highly enriched uranium and weapon-grade plutonium and that the main fissile material was 235U (about 4 times more than the mass of 239Pu). In the five hot particles examined, the measured uranium atomic ratio was 235U/238U = 1.02 +/- 0.16 and the Pu-isotopic ratios were as follows: 24Pu/239Pu = 0.0551 +/- 0.0008 (atom ratio), 238Pu/239+240Pu = 0.0161 +/- 0.0005 (activity ratio), 241Pu/239+240Pu = 0.87 +/- 0.12 (activity ratio), and 241Am/ 239+240Pu = 0.169 +/- 0.005 (activity ratio) (reference date 2001-10-01). From the activity ratios of 241Pu/241Am, we estimated the time of production of this weapon material to be from the late 1950s to the early 1960s. The results from reanalyzed bulk sediment samples showed the presence of more than one Pu source involved in the accident, confirming earlier studies. The 238Pu/239+240PU activity ratio and the 240Pu/ 239Pu atomic ratio were divided into at least two Pu-isotopic ratio groups. For both Pu-isotopic ratios, one ratio group had identical ratios as the five hot particles described above and for the other groups the Pu isotopic ratios were lower (238Pu/ 239+240PU activity ratio approximately 0.01 and the 240Pu/P239Pu atomic ratio 0.03). On the studied particles we observed that the U/Pu ratio decreased as a function of the time these particles were present in the sediment. We hypothesis that the decrease in the ratio is due to a preferential leaching of U relative to Pu from the particle matrix.

Study of nuclear matter in hard proton-nuclei and nuclei-nuclei collisions at the U70 accelerator (FLUKTON project proposal)

NASA Astrophysics Data System (ADS)

Antonov, N. N.; Baldin, A. A.; Viktorov, V. A.; Gapienko, V. A.; Gapienko, G. S.; Gres, V. N.; Ilyushin, M. A.; Korotkov, V. A.; Mysnik, A. I.; Prudkoglyad, A. F.; Pryanikov, D. S.; Semak, A. A.; Stavinsky, A. V.; Terekhov, V. I.; Uglekov, V. Ya.; Ukhanov, M. N.; Chuiko, B. V.; Shimansky, S. S.

2017-11-01

A two-arm spectrometer FLUKTON for investigations in the field of relativistic nuclear physics at U70 energies is proposed to be constructed on base of the existing detector SPIN (IHEP, Protvino). The main objective is to obtain new data on clusters of cold superdense nuclear matter. Interaction of a high intensity proton beam with nuclear targets and an ion beam with liquid hydrogen and nuclear targets will be studied.

IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

DOE PAGES

Capote, R.; Trkov, A.; Sin, M.; ...

2018-02-01

Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10 -5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE–3.2more » Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(n th,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good

IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

NASA Astrophysics Data System (ADS)

Capote, R.; Trkov, A.; Sin, M.; Pigni, M. T.; Pronyaev, V. G.; Balibrea, J.; Bernard, D.; Cano-Ott, D.; Danon, Y.; Daskalakis, A.; Goričanec, T.; Herman, M. W.; Kiedrowski, B.; Kopecky, S.; Mendoza, E.; Neudecker, D.; Leal, L.; Noguere, G.; Schillebeeckx, P.; Sirakov, I.; Soukhovitskii, E. S.; Stetcu, I.; Talou, P.

2018-02-01

Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10-5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE-3.2 Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(nth,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good performance in

IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

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

Capote, R.; Trkov, A.; Sin, M.

Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10 -5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE–3.2more » Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(n th,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good

How small firms contrast with large firms regarding perceptions, practices, and needs in the U.S

Treesearch

Urs Buehlmann; Matthew Bumgardner; Michael Sperber

2013-01-01

As many larger secondary woodworking firms have moved production offshore and been adversely impacted by the recent housing downturn, smaller firms have become important to driving U.S. hardwood demand. This study compared and contrasted small and large firms on a number of factors to help determine the unique characteristics of small firms and to provide insights into...

Myeloid leukemia factor 1 associates with a novel heterogeneous nuclear ribonucleoprotein U-like molecule.

PubMed

Winteringham, Louise N; Endersby, Raelene; Kobelke, Simon; McCulloch, Ross K; Williams, James H; Stillitano, Justin; Cornwall, Scott M; Ingley, Evan; Klinken, S Peter

2006-12-15

Myeloid leukemia factor 1 (MLF1) is an oncoprotein associated with hemopoietic lineage commitment and acute myeloid leukemia. Here we show that Mlf1 associated with a novel binding partner, Mlf1-associated nuclear protein (Manp), a new heterogeneous nuclear ribonucleoprotein (hnRNP) family member, related to hnRNP-U. Manp localized exclusively in the nucleus and could redirect Mlf1 from the cytoplasm into the nucleus. The nuclear content of Mlf1 was also regulated by 14-3-3 binding to a canonical 14-3-3 binding motif within the N terminus of Mlf1. Significantly Mlf1 contains a functional nuclear export signal and localized primarily to the nuclei of hemopoietic cells. Mlf1 was capable of binding DNA, and microarray analysis revealed that it affected the expression of several genes, including transcription factors. In summary, this study reveals that Mlf1 translocates between nucleus and cytoplasm, associates with a novel hnRNP, and influences gene expression.

Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

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

Bruce G. Schnitzler; Stanley K. Borowski

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified asmore » the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine

Precise U and Pu isotope ratio measurements in nuclear samples by hyphenating capillary electrophoresis and MC-ICPMS.

PubMed

Martelat, Benoit; Isnard, Helene; Vio, Laurent; Dupuis, Erwan; Cornet, Terence; Nonell, Anthony; Chartier, Frederic

2018-06-22

Precise isotopic and elemental characterization of spent nuclear fuel is a major concern for the validation of the neutronic calculation codes and waste management strategy in the nuclear industry. Generally, the elements of interest, particularly U and Pu which are the two major elements present in spent fuel, are purified by ion exchange or extractant resins before off-line measurements by thermal ionization mass spectrometry. The aim of the present work was to develop a new analytical approach based on capillary electrophoresis (CE) hyphenated to a multicollector inductively coupled plasma mass spectrometer (MC-ICPMS) for online isotope ratio measurements. An electrophoretic separation protocol of U, Pu and the fraction containing fission products and minor actinides (Am and Cm) was developed using acetic acid as the electrolyte and complexing agent. The instrumentation for CE was designed to be used in a glove box and a laboratory-built interface was developed for hyphenation with MC-ICPMS. The separation was realized with only a few nL of a solution of spent nuclear fuel and the reproducibilities obtained on the U and Pu isotope ratios were on the order of a few ‰ which is comparable to those obtained by thermal ionization mass spectrometer (TIMS). This innovative protocol allowed a tremendous reduction of the analyte masses from μg to ng and also a drastic reduction of the liquid waste production from mL to μL. In addition, the time of analysis was shorted by at least a factor three. All of these improved parameters are of major interest for nuclear applications.

Nuclear magnetic resonance studies of pseudospin fluctuations in URu 2 Si 2

DOE PAGES

Shirer, K. R.; Haraldsen, J. T.; Dioguardi, A. P.; ...

2013-09-26

Here, we report 29Si nuclear magnetic resonance measurements in single crystals and aligned powders of URu 2Si 2 in the hidden order and paramagnetic phases. The spin-lattice relaxation data reveal evidence of pseudospin fluctuations of U moments in the paramagnetic phase. We find evidence for partial suppression of the density of states below 30 K and analyze the data in terms of a two-component spin-fermion model. We propose that this behavior is a realization of a pseudogap between the hidden-order transition T HO and 30 K. This behavior is then compared to other materials that demonstrate precursor fluctuations in amore » pseudogap regime above a ground state with long-range order.« less

U bodies respond to nutrient stress in Drosophila

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

Buckingham, Mickey; Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk

The neurodegenerative disease spinal muscular atrophy (SMA) is caused by mutation of the survival motor neuron 1 (SMN1) gene. Cytoplasmic SMN protein-containing granules, known as U snRNP bodies (U bodies), are thought to be responsible for the assembly and storage of small nuclear ribonucleoproteins (snRNPs) which are essential for pre-mRNA splicing. U bodies exhibit close association with cytoplasmic processing bodies (P bodies), which are involved in mRNA decay and translational repression. The close association of the U body and P body in Drosophila resemble that of the stress granule and P body in yeast and mammalian cells. However, it ismore » unknown whether the U body is responsive to any stress. Using Drosophila oogenesis as a model, here we show that U bodies increase in size following nutritional deprivation. Despite nutritional stress, U bodies maintain their close association with P bodies. Our results show that U bodies are responsive to nutrition changes, presumably through the U body-P body pathway.« less

Processing of U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys by sintering process

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

Dos Santos, A. M. M.; Ferraz, W. B.; Lameiras, F. S.

2012-07-01

To minimize the risk of nuclear proliferation, there is worldwide interest in reducing fuel enrichment of research and test reactors. To achieve this objective while still guaranteeing criticality and cycle length requirements, there is need of developing high density uranium metallic fuels. Alloying elements such as Zr, Nb and Mo are added to uranium to improve fuel performance in reactors. In this context, the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) is developing the U-2.5Zr-7.5Nb and U-3Zr-9Nb (weight %) alloys by the innovative process of sintering that utilizes raw materials in the form of powders. The powders were pressed atmore » 400 MPa and then sintered under a vacuum of about 1x10{sup -4} Torr at temperatures ranging from 1050 deg. to 1500 deg.C. The densities of the alloys were measured geometrically and by hydrostatic method and the phases identified by X ray diffraction (XRD). The microstructures of the pellets were observed by scanning electron microscopy (SEM) and the alloying elements were analyzed by energy dispersive X-ray spectroscopy (EDS). The results obtained showed the fuel density to slightly increase with the sintering temperature. The highest density achieved was approximately 80% of theoretical density. It was observed in the pellets a superficial oxide layer formed during the sintering process. (authors)« less

Preserving the nuclear option: The AIAA position paper on space nuclear power

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

Allen, D.M.; Bennett, G.L.; El-Genk, M.S.

1996-03-01

In response to published reports about the decline in funding for space nuclear power, the Board of Directors of the American Institute of Aeronautics and Astronautics (AIAA) approved a position paper in March 1995 that recommends (1) development and support of an integrated space nuclear power program by DOE, NASA and DoD; (2) Congressional support for the program; (3) advocacy of the program by government and industry leaders; and (4) continuation of cooperation between the U.S. and other countries to advance nuclear power source technology and to promote safety. This position paper has been distributed to various people having oversightmore » of the U.S. space nuclear power program. {copyright} {ital 1996 American Institute of Physics.}« less

NUCLEAR REACTOR

DOEpatents

Young, G.

1963-01-01

This patent covers a power-producing nuclear reactor in which fuel rods of slightly enriched U are moderated by heavy water and cooled by liquid metal. The fuel rods arranged parallel to one another in a circle are contained in a large outer closed-end conduit that extends into a tank containing the heavy water. Liquid metal is introduced into the large conduit by a small inner conduit that extends within the circle of fuel rods to a point near the lower closed end of the outer conduit. (AEC) Production Reactors

A Novel Intra-U1 snRNP Cross-Regulation Mechanism: Alternative Splicing Switch Links U1C and U1-70K Expression

PubMed Central

Rösel-Hillgärtner, Tanja Dorothe; Hung, Lee-Hsueh; Khrameeva, Ekaterina; Le Querrec, Patrick; Gelfand, Mikhail S.; Bindereif, Albrecht

2013-01-01

The U1 small nuclear ribonucleoprotein (snRNP)-specific U1C protein participates in 5′ splice site recognition and regulation of pre-mRNA splicing. Based on an RNA-Seq analysis in HeLa cells after U1C knockdown, we found a conserved, intra-U1 snRNP cross-regulation that links U1C and U1-70K expression through alternative splicing and U1 snRNP assembly. To investigate the underlying regulatory mechanism, we combined mutational minigene analysis, in vivo splice-site blocking by antisense morpholinos, and in vitro binding experiments. Alternative splicing of U1-70K pre-mRNA creates the normal (exons 7–8) and a non-productive mRNA isoform, whose balance is determined by U1C protein levels. The non-productive isoform is generated through a U1C-dependent alternative 3′ splice site, which requires an adjacent cluster of regulatory 5′ splice sites and binding of intact U1 snRNPs. As a result of nonsense-mediated decay (NMD) of the non-productive isoform, U1-70K mRNA and protein levels are down-regulated, and U1C incorporation into the U1 snRNP is impaired. U1-70K/U1C-deficient particles are assembled, shifting the alternative splicing balance back towards productive U1-70K splicing, and restoring assembly of intact U1 snRNPs. Taken together, we established a novel feedback regulation that controls U1-70K/U1C homeostasis and ensures correct U1 snRNP assembly and function. PMID:24146627

Quantifying Morphological Features of α-U3O8 with Image Analysis for Nuclear Forensics.

PubMed

Olsen, Adam M; Richards, Bryony; Schwerdt, Ian; Heffernan, Sean; Lusk, Robert; Smith, Braxton; Jurrus, Elizabeth; Ruggiero, Christy; McDonald, Luther W

2017-03-07

Morphological changes in U 3 O 8 based on calcination temperature have been quantified enabling a morphological feature to serve as a signature of processing history in nuclear forensics. Five separate calcination temperatures were used to synthesize α-U 3 O 8 , and each sample was characterized using powder X-ray diffraction (p-XRD) and scanning electron microscopy (SEM). The p-XRD spectra were used to evaluate the purity of the synthesized U-oxide; the morphological analysis for materials (MAMA) software was utilized to quantitatively characterize the particle shape and size as indicated by the SEM images. Analysis comparing the particle attributes, such as particle area at each of the temperatures, was completed using the Kolmogorov-Smirnov two sample test (K-S test). These results illustrate a distinct statistical difference between each calcination temperature. To provide a framework for forensic analysis of an unknown sample, the sample distributions at each temperature were compared to randomly selected distributions (100, 250, 500, and 750 particles) from each synthesized temperature to determine if they were statistically different. It was found that 750 particles were required to differentiate between all of the synthesized temperatures with a confidence interval of 99.0%. Results from this study provide the first quantitative morphological study of U-oxides, and reveals the potential strength of morphological particle analysis in nuclear forensics by providing a framework for a more rapid characterization of interdicted uranium oxide samples.

Climatic Consequences of Nuclear Conflict

NASA Astrophysics Data System (ADS)

Robock, A.

2011-12-01

A nuclear war between Russia and the United States could still produce nuclear winter, even using the reduced arsenals of about 4000 total nuclear weapons that will result by 2017 in response to the New START treaty. A nuclear war between India and Pakistan, with each country using 50 Hiroshima-sized atom bombs as airbursts on urban areas, could produce climate change unprecedented in recorded human history. This scenario, using much less than 1% of the explosive power of the current global nuclear arsenal, would produce so much smoke from the resulting fires that it would plunge the planet to temperatures colder than those of the Little Ice Age of the 16th to 19th centuries, shortening the growing season around the world and threatening the global food supply. Crop model studies of agriculture in the U.S. and China show massive crop losses, even for this regional nuclear war scenario. Furthermore, there would be massive ozone depletion with enhanced ultraviolet radiation reaching the surface. These surprising conclusions are the result of recent research (see URL) by a team of scientists including those who produced the pioneering work on nuclear winter in the 1980s, using the NASA GISS ModelE and NCAR WACCM GCMs. The soot is self-lofted into the stratosphere, and the effects of regional and global nuclear war would last for more than a decade, much longer than previously thought. Nuclear proliferation continues, with nine nuclear states now, and more working to develop or acquire nuclear weapons. The continued environmental threat of the use of even a small number of nuclear weapons must be considered in nuclear policy deliberations in Russia, the U.S., and the rest of the world.

Nuclear Fuels.

ERIC Educational Resources Information Center

Nash, J. Thomas

1983-01-01

Trends in and factors related to the nuclear industry and nuclear fuel production are discussed. Topics addressed include nuclear reactors, survival of the U.S. uranium industry, production costs, budget cuts by the Department of Energy and U.S. Geological survey for resource studies, mining, and research/development activities. (JN)

Impact of thermal spectrum small modular reactors on performance of once-through nuclear fuel cycles with low-enriched uranium

DOE PAGES

Brown, Nicholas R.; Worrall, Andrew; Todosow, Michael

2016-11-18

Small modular reactors (SMRs) offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of SMRs on nuclear fuel cycle performance. The focus of this paper is the fuel cycle impacts of light water SMRs in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary example reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Options Campaign. The hypothetical light water SMR example case considered in these preliminary scoping studies ismore » a cartridge type one-batch core with slightly less than 5.0% enrichment. Challenges associated with SMRs include increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burnup in the reactor and the fuel cycle performance. This paper summarizes a list of the factors relevant to SMR fuel, core, and operation that will impact fuel cycle performance. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burnup of the reactor. Fuel cycle performance metrics for a hypothetical example SMR are compared with those for a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. The metrics performance for such an SMR is degraded for the mass of spent nuclear fuel and high-level waste disposed of, mass of depleted uranium

Thermal expansion of the nuclear fuel-sodium reaction product Na3(U0.84(2),Na0.16(2))O4 - Structural mechanism and comparison with related sodium-metal ternary oxides

NASA Astrophysics Data System (ADS)

Illy, Marie-Claire; Smith, Anna L.; Wallez, Gilles; Raison, Philippe E.; Caciuffo, Roberto; Konings, Rudy J. M.

2017-07-01

Na3.16(2)UV,VI0.84(2)O4 is obtained from the reaction of sodium with uranium dioxide under oxygen potential conditions typical of a sodium-cooled fast nuclear reactor. In the event of a breach of the steel cladding, it would be the dominant reaction product forming at the rim of the mixed (U,Pu)O2 fuel pellets. High-temperature X-ray diffraction measurements show that a distortion of the uranium environment in Na3.16(2)UV,VI0.84(2)O4 results in a strongly anisotropic thermal expansion. A comparison with several related sodium metallates Nan-2Mn+On-1 - including Na3SbO4 and Na3TaO4, whose crystal structures are reported for the first time - has allowed us to assess the role played in the lattice expansion by the Mn+ cation radius and the Na/M ratio. On this basis, the thermomechanical behavior of the title compound is discussed, along with those of several related double oxides of sodium and actinide elements, surrogate elements, or fission products.

Re-refinement of the spliceosomal U4 snRNP core-domain structure

PubMed Central

Li, Jade; Leung, Adelaine K.; Kondo, Yasushi; Oubridge, Chris; Nagai, Kiyoshi

2016-01-01

The core domain of small nuclear ribonucleoprotein (snRNP), comprised of a ring of seven paralogous proteins bound around a single-stranded RNA sequence, functions as the assembly nucleus in the maturation of U1, U2, U4 and U5 spliceosomal snRNPs. The structure of the human U4 snRNP core domain was initially solved at 3.6 Å resolution by experimental phasing using data with tetartohedral twinning. Molecular replacement from this model followed by density modification using untwinned data recently led to a structure of the minimal U1 snRNP at 3.3 Å resolution. With the latter structure providing a search model for molecular replacement, the U4 core-domain structure has now been re-refined. The U4 Sm site-sequence AAUUUUU has been shown to bind to the seven Sm proteins SmF–SmE–SmG–SmD3–SmB–SmD1–SmD2 in an identical manner as the U1 Sm-site sequence AAUUUGU, except in SmD1 where the bound U replaces G. The progression from the initial to the re-refined structure exemplifies a tortuous route to accuracy: where well diffracting crystals of complex assemblies are initially unavailable, the early model errors are rectified by exploiting preliminary interpretations in further experiments involving homologous structures. New insights are obtained from the more accurate model. PMID:26894541

The minor spliceosomal protein U11/U12-31K is an RNA chaperone crucial for U12 intron splicing and the development of dicot and monocot plants.

PubMed

Kwak, Kyung Jin; Jung, Hyun Ju; Lee, Kwang Ho; Kim, Young Soon; Kim, Won Yong; Ahn, Sung Ju; Kang, Hunseung

2012-01-01

U12 intron-specific spliceosomes contain U11 and U12 small nuclear ribonucleoproteins and mediate the removal of U12 introns from precursor-mRNAs. Among the several proteins unique to the U12-type spliceosomes, an Arabidopsis thaliana AtU11/U12-31K protein has been shown to be indispensible for proper U12 intron splicing and for normal growth and development of Arabidopsis plants. Here, we assessed the functional roles of the rice (Oryza sativa) OsU11/U12-31K protein in U12 intron splicing and development of plants. The U11/U12-31K transcripts were abundantly expressed in the shoot apical meristems (SAMs) of Arabidopsis and rice. Ectopic expression of OsU11/U12-31K in AtU11/U12-31K-defecient Arabidopsis mutant complemented the incorrect U12 intron splicing and abnormal development phenotypes of the Arabidopsis mutant plants. Impaired cell division activity in the SAMs and inflorescence stems observed in the AtU11/U12-31K-deficient mutant was completely recovered to normal by the expression of OsU11/U12-31K. Similar to Arabidopsis AtU11/U12-31K, rice OsU11/U12-31K was determined to harbor RNA chaperone activity. Collectively, the present findings provide evidence for the emerging idea that the U11/U12-31K protein is an indispensible RNA chaperone that functions in U12 intron splicing and is necessary for normal development of monocotyledonous plants as well as dicotyledonous plants.

Local U(2,2) symmetry in relativistic quantum mechanics

NASA Astrophysics Data System (ADS)

Finster, Felix

1998-12-01

Local gauge freedom in relativistic quantum mechanics is derived from a measurement principle for space and time. For the Dirac equation, one obtains local U(2,2) gauge transformations acting on the spinor index of the wave functions. This local U(2,2) symmetry allows a unified description of electrodynamics and general relativity as a classical gauge theory.

75 FR 3497 - Entergy Nuclear Operations, Inc., Entergy Nuclear Indian Point 2, LLC, Entergy Nuclear Indian...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-21

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-247 and 50-286; NRC-2010-0006] Entergy Nuclear Operations, Inc., Entergy Nuclear Indian Point 2, LLC, Entergy Nuclear Indian Point 3, LLC,: Indian Point Nuclear Generating Unit Nos. 2 and 3; Notice of Consideration of Issuance of Amendment to Facility Operating License and Opportunity To Request a...

Science, Society, and America's Nuclear Waste: Ionizing Radiation, Unit 2. Teacher Guide. Second Edition.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC. Office of Civilian Radioactive Waste Management, Washington, DC.

This guide is Unit 2 of the four-part series, Science, Society, and America's Nuclear Waste, produced by the U.S. Department of Energy's Office of Civilian Radioactive Waste Management. The goal of this unit is to convey factual information relevant to radioactivity and radiation and relate that information both to the personal lives of students…

Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

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

Susmikanti, Mike, E-mail: mike@batan.go.id; Sulistyo, Jos, E-mail: soj@batan.go.id

2014-09-30

Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to developmore » code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix.« less

Isolation and characterization of rabbit anti-m3 2,2,7G antibodies.

PubMed Central

Luhrmann, R; Appel, B; Bringmann, P; Rinke, J; Reuter, R; Rothe, S; Bald, R

1982-01-01

Antibodies specific for intact 2,2,7-trimethylguanosine (m3 2,2,7G) were induced by immunization of rabbits with a nucleoside-human serum albumen (HSA) conjugate. Competition radioimmunoassay showed that the antibody distinguishes well between intact m3 2,2,7G and its alkali-hydrolysed form (m3 2,2,7G*). Antibody specificity is largely dependent on the presence of all three methyl groups in m3 2,2,7G: none of the less extensively methylated nucleosides m7G, m2G and m2 2,2G is able to compete efficiently with the homologous hapten. Little or no competition was observed with m1G, m1A, m6A, m5U and each of the four unmodified ribonucleosides. Binding studies with nucleoplasmic RNAs from Ehrlich ascites cells suggest that the antibody reacts specifically with the m3 2,2,7G-containing cap structure of the small nuclear U-RNAs (U-snRNAs). Thus the antibody should be a valuable tool for studying the role of the 5'-terminal regions of the U-snRNAs of eucaryotic cells. Images PMID:7155893

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

78 FR 35646 - Byron Nuclear Station, Units 1 and 2, and Braidwood Nuclear Station, Units 1 and 2

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-13

... NUCLEAR REGULATORY COMMISSION [Docket Nos.: 50-454, 50-455, 50-456, 50-457; NRC-2013-0126] Byron Nuclear Station, Units 1 and 2, and Braidwood Nuclear Station, Units 1 and 2 AGENCY: Nuclear Regulatory.... Nuclear Regulatory Commission (NRC) has received an application, dated May 29, 2013, from Exelon...

Cross section for the subthreshold fission of 236U

NASA Astrophysics Data System (ADS)

Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A.; Samylin, B. F.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S.

2008-08-01

The cross section for 236U fission in the neutron-energy range E n = 0.001 20 keV was measured by using the INR RAS (Institute of Nuclear Research, Russian Academy of Sciences, Moscow) LSDS-100 neutron spectrometer of the lead slowing-down spectrometer type. The resonance fission areas of the resonances at 5.45 eV and 1.28 keV were found, and the fission widths of these resonances were evaluated. The cross section for the 238U( n, f) fission process was measured, and the threshold sensitivity of the LSDS-100 to small values of fission cross sections was estimated. The well-known intermediate structure in the cross section for the neutron-induced subbarrier fission of 236U was confirmed.

NREL to Work with 14 Additional Small Businesses as Part of the DOE Small

Science.gov Websites

Business Vouchers Program | NREL | News | NREL to Work with 14 Additional Small Businesses as Part of the DOE Small Business Vouchers Program News Release: NREL to Work with 14 Additional Small Businesses as Part of the DOE Small Business Vouchers Program May 2, 2017 The U.S. Department of Energy's

78 FR 66950 - Trade Barriers That U.S. Small and Medium-Sized Enterprises Perceive as Affecting Exports to the...

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2013-11-07

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U.S. and Russian Collaboration in the Area of Nuclear Forensics

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

Kristo, M J

2007-10-22

Nuclear forensics has become increasingly important in the fight against illicit trafficking in nuclear and other radioactive materials. The illicit trafficking of nuclear materials is, of course, an international problem; nuclear materials may be mined and milled in one country, manufactured in a second country, diverted at a third location, and detected at a fourth. There have been a number of articles in public policy journals in the past year that call for greater interaction between the U. S. and the rest of the world on the topic of nuclear forensics. Some believe that such international cooperation would help providemore » a more certain capability to identify the source of the nuclear material used in a terrorist event. An improved international nuclear forensics capability would also be important as part of the IAEA verification toolkit, particularly linked to increased access provided by the additional protocol. A recent study has found that, although international progress has been made in securing weapons-usable HEU and Pu, the effort is still insufficient. They found that nuclear material, located in 40 countries, could be obtained by terrorists and criminals and used for a crude nuclear weapon. Through 2006, the IAEA Illicit Trafficking Database had recorded a total of 607 confirmed events involving illegal possession, theft, or loss of nuclear and other radioactive materials. Although it is difficult to predict the future course of such illicit trafficking, increasingly such activities are viewed as significant threats that merit the development of special capabilities. As early as April, 1996, nuclear forensics was recognized at the G-8 Summit in Moscow as an important element of an illicit nuclear trafficking program. Given international events over the past several years, the value and need for nuclear forensics seems greater than ever. Determining how and where legitimate control of nuclear material was lost and tracing the route of the

Static electric dipole polarizabilities of An(5+/6+) and AnO2 (+/2+) (An = U, Np, and Pu) ions.

PubMed

Parmar, Payal; Peterson, Kirk A; Clark, Aurora E

2014-12-21

The parallel components of static electric dipole polarizabilities have been calculated for the lowest lying spin-orbit states of the penta- and hexavalent oxidation states of the actinides (An) U, Np, and Pu, in both their atomic and molecular diyl ion forms (An(5+/6+) and AnO2 (+/2+)) using the numerical finite-field technique within a four-component relativistic framework. The four-component Dirac-Hartree-Fock method formed the reference for MP2 and CCSD(T) calculations, while multireference Fock space coupled-cluster (FSCC), intermediate Hamiltonian Fock space coupled-cluster (IH-FSCC) and Kramers restricted configuration interaction (KRCI) methods were used to incorporate additional electron correlation. It is observed that electron correlation has significant (∼5 a.u.(3)) impact upon the parallel component of the polarizabilities of the diyls. To the best of our knowledge, these quantities have not been previously reported and they can serve as reference values in the determination of various electronic and response properties (for example intermolecular forces, optical properties, etc.) relevant to the nuclear fuel cycle and material science applications. The highest quality numbers for the parallel components (αzz) of the polarizability for the lowest Ω levels corresponding to the ground electronic states are (in a.u.(3)) 44.15 and 41.17 for UO2 (+) and UO2 (2+), respectively, 45.64 and 41.42 for NpO2 (+) and NpO2 (2+), respectively, and 47.15 for the PuO2 (+) ion.

Magnetotransport and Heat Capacity in Ternary Compounds U3M2M‧3‧, M=Al, Ga; M=Si, Ge

NASA Astrophysics Data System (ADS)

Troć, R.; Rogl, P.; Tran, V. H.; Czopnik, A.

2001-05-01

We report detailed studies of magnetization, electrical resistivity, magnetoresistivity, and heat capacity performed on the novel family of intermetallic compounds U3M2M‧3, (M=Al, Ga, and M‧=Si, Ge). The present measurements support the earlier conclusions about the ferrimagnetic properties of silicides and ferromagnetic properties of germanides. The resistivity for both compounds U3{Al,Ga}2Si3 exhibits below TC a pronounced maximum observed for the first time in an actinoid-ferrimagnet, probably caused by (a) the reduction of the number of effective conduction carriers or (b) a SDW-type of spin-disorder scattering of electrons. Both low-temperature resistivity (except for U3Ga2Si3) and heat capacity may be described by a T-dependence involving a small gap Δ on the order of 30-50 K in the magnon dispersion. The Cp/T values at 2 K are enhanced and point to a medium-heavy fermion character of all these ternaries. Magnetoresistance for ferrimagnetic U3{Al,Ga}2Si3 is rather small but positive in correspondence of antiferromagnetic interactions. In correspondence to the ferromagnetic materials, negative magnetoresistance is encountered for U3{Al,Ga}2Ge3. Specific features in the temperature dependence of magnetoresistivity Δρ/ρ at various fields confirm the sinusoidal modulation of the magnetic structure for U3Al2Ge3 between 40 and 60 K. Also, such data for U3Ga2Ge3 present strong indications for a similar magnetic modulation between 63 and 93 K, yet to be discovered by neutron diffraction experiments. In addition, the transition at 63 K is furthermore well resolved in the specific heat data of U3Ga2Ge3.

Oxygen diffusion model of the mixed (U,Pu)O2 ± x: Assessment and application

NASA Astrophysics Data System (ADS)

Moore, Emily; Guéneau, Christine; Crocombette, Jean-Paul

2017-03-01

The uranium-plutonium (U,Pu)O2 ± x mixed oxide (MOX) is used as a nuclear fuel in some light water reactors and considered for future reactor generations. To gain insight into fuel restructuring, which occurs during the fuel lifetime as well as possible accident scenarios understanding of the thermodynamic and kinetic behavior is crucial. A comprehensive evaluation of thermo-kinetic properties is incorporated in a computational CALPHAD type model. The present DICTRA based model describes oxygen diffusion across the whole range of plutonium, uranium and oxygen compositions and temperatures by incorporating vacancy and interstitial migration pathways for oxygen. The self and chemical diffusion coefficients are assessed for the binary UO2 ± x and PuO2 - x systems and the description is extended to the ternary mixed oxide (U,Pu)O2 ± x by extrapolation. A simulation to validate the applicability of this model is considered.

A SPACESHIP WITH NUCLEAR PROPULSION

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

Polorny, J.

1962-01-01

ABS>A proposed space vehicle with nuclear propulsion for a round-trip Martian mission is described. It would be powered by a 270-Mw graphite- moderated, U-fueled nuclear reactor with a core 1 m high by 1 m in diameter, and use gas as propellant. The gas would be heated to the maximum temperature in the reactor and additionally accelerated by an electromagnetic field. To this end, small quantities of K would be injected into the gas stream to increase its electric conductivity. The required electrical energy would be produced by liquid-Na-cooled thermionic converters. The vehicle would weigh 115000 kg, including 43000 kgmore » of H propellant with tankage, and 7000 kg of sustenance material for one year. Chemical rockets would launch the vehicle with a crew of three men into an earth orbit where nuclear propulsion would take over. Upon reactor start-up, three heat exchangers (minimum dimensions 30 x 18 m) would be fanned out. A shielded well with a diameter of 2.5 m would protect the crew from radiation during reactor operation, passage through the earth radiation belts, and at periods of solar flares. (OTS)« less

Nuclear export of the small ribosomal subunit requires the Ran–GTPase cycle and certain nucleoporins

PubMed Central

Moy, Terence I.; Silver, Pamela A.

1999-01-01

After their assembly in the nucleolus, ribosomal subunits are exported from the nucleus to the cytoplasm. After export, the 20S rRNA in the small ribosomal subunit is cleaved to yield 18S rRNA and the small 5′ ITS1 fragment. The 5′ ITS1 RNA is normally degraded by the cytoplasmic Xrn1 exonuclease, but in strains lacking XRN1, the 5′ ITS1 fragment accumulates in the cytoplasm. Using the cytoplasmic localization of the 5′ ITS1 fragment as an indicator for the export of the small ribosomal subunit, we have identified genes that are required for ribosome export. Ribosome export is dependent on the Ran–GTPase as mutations in Ran or its regulators caused 5′ ITS1 to accumulate in the nucleoplasm. Mutations in the genes encoding the nucleoporin Nup82 and in the NES exporter Xpo1/Crm1 also caused the nucleoplasmic accumulation of 5′ ITS1. Mutants in a subset of nucleoporins and in the nuclear transport factors Srp1, Kap95, Pse1, Cse1, and Mtr10 accumulate the 5′ ITS1 in the nucleolus and affect ribosome assembly. In contrast, we did not detect nuclear accumulation of 5′ ITS1 in 28 yeast strains that have mutations in other genes affecting nuclear trafficking. PMID:10465789

33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...

33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...

33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...

33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...

REGIONAL SEISMIC CHEMICAL AND NUCLEAR EXPLOSION DISCRIMINATION: WESTERN U.S. EXAMPLES

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

Walter, W R; Taylor, S R; Matzel, E

2006-07-07

We continue exploring methodologies to improve regional explosion discrimination using the western U.S. as a natural laboratory. The western U.S. has abundant natural seismicity, historic nuclear explosion data, and widespread mine blasts, making it a good testing ground to study the performance of regional explosion discrimination techniques. We have assembled and measured a large set of these events to systematically explore how to best optimize discrimination performance. Nuclear explosions can be discriminated from a background of earthquakes using regional phase (Pn, Pg, Sn, Lg) amplitude measures such as high frequency P/S ratios. The discrimination performance is improved if the amplitudesmore » can be corrected for source size and path length effects. We show good results are achieved using earthquakes alone to calibrate for these effects with the MDAC technique (Walter and Taylor, 2001). We show significant further improvement is then possible by combining multiple MDAC amplitude ratios using an optimized weighting technique such as Linear Discriminant Analysis (LDA). However this requires data or models for both earthquakes and explosions. In many areas of the world regional distance nuclear explosion data is lacking, but mine blast data is available. Mine explosions are often designed to fracture and/or move rock, giving them different frequency and amplitude behavior than contained chemical shots, which seismically look like nuclear tests. Here we explore discrimination performance differences between explosion types, the possible disparity in the optimization parameters that would be chosen if only chemical explosions were available and the corresponding effect of that disparity on nuclear explosion discrimination. Even after correcting for average path and site effects, regional phase ratios contain a large amount of scatter. This scatter appears to be due to variations in source properties such as depth, focal mechanism, stress drop, in the near

Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K

PubMed Central

Pöschko, Maria Theresia; Vuichoud, Basile; Milani, Jonas; Bornet, Aurélien; Bechmann, Matthias; Bodenhausen, Geoffrey; Jannin, Sami; Müller, Norbert

2015-01-01

We report proton spin noise spectra of a hyperpolarized solid sample of commonly used “DNP (dynamic nuclear polarization) juice” containing TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide) and irradiated by a microwave field at a temperature of 1.2 K in a magnetic field of 6.7 T. The line shapes of the spin noise power spectra are sensitive to the variation of the microwave irradiation frequency and change from dip to bump, when the electron Larmor frequency is crossed, which is shown to be in good accordance with theory by simulations. Small but significant deviations from these predictions are observed, which can be related to spin noise and radiation damping phenomena that have been reported in thermally polarized systems. The non-linear dependence of the spin noise integral on nuclear polarization provides a means to monitor hyperpolarization semi-quantitatively without any perturbation of the spin system by radio frequency irradiation. PMID:26477605

Modelling the thermal conductivity of (U xTh 1-x)O 2 and (U xPu 1-x)O 2

DOE PAGES

Cooper, M. W. D.; Middleburgh, S. C.; Grimes, R. W.

2015-07-15

The degradation of thermal conductivity due to the non-uniform cation lattice of (U xTh 1-x)O 2 and (U xPu 1-x)O 2 solid solutions has been investigated by molecular dynamics, using the non-equilibrium method, from 300 to 2000 K. Degradation of thermal conductivity is predicted in (U xTh 1-x)O 2 and (U xPu 1-x)O 2 as compositions deviate from the pure end members: UO 2, PuO 2 and ThO 2. The reduction in thermal conductivity is most apparent at low temperatures where phonon-defect scattering dominates over phonon-phonon interactions. The effect is greater for (U xTh 1-x)O 2 than U xPu 1-x)Omore » 2 due to the greater mismatch in cation size. Parameters for an analytical expressions have been developed that describe the predicted thermal conductivities over the full temperature and compositional ranges. Finally, these expressions may be used in higher level fuel performance codes.« less

Annealing tests of in-pile irradiated oxide coated U-Mo/Al-Si dispersed nuclear fuel

NASA Astrophysics Data System (ADS)

Zweifel, T.; Valot, Ch.; Pontillon, Y.; Lamontagne, J.; Vermersch, A.; Barrallier, L.; Blay, T.; Petry, W.; Palancher, H.

2014-09-01

U-Mo/Al based nuclear fuels have been worldwide considered as a promising high density fuel for the conversion of high flux research reactors from highly enriched uranium to lower enrichment. In this paper, we present the annealing test up to 1800 °C of in-pile irradiated U-Mo/Al-Si fuel plate samples. More than 70% of the fission gases (FGs) are released during two major FG release peaks around 500 °C and 670 °C. Additional characterisations of the samples by XRD, EPMA and SEM suggest that up to 500 °C FGs are released from IDL/matrix interfaces. The second peak at 670 °C representing the main release of FGs originates from the interaction between U-Mo and matrix in the vicinity of the cladding.

Human U2 snRNA Genes Exhibit a Persistently Open Transcriptional State and Promoter Disassembly at Metaphase▿

PubMed Central

Pavelitz, Thomas; Bailey, Arnold D.; Elco, Christopher P.; Weiner, Alan M.

2008-01-01

In mammals, small multigene families generate spliceosomal U snRNAs that are nearly as abundant as rRNA. Using the tandemly repeated human U2 genes as a model, we show by footprinting with DNase I and permanganate that nearly all sequences between the enhancer-like distal sequence element and the initiation site are protected during interphase whereas the upstream half of the U2 snRNA coding region is exposed. We also show by chromatin immunoprecipitation that the SNAPc complex, which binds the TATA-like proximal sequence element, is removed at metaphase but remains bound under conditions that induce locus-specific metaphase fragility of the U2 genes, such as loss of CSB, BRCA1, or BRCA2 function, treatment with actinomycin D, or overexpression of the tetrameric p53 C terminus. We propose that the U2 snRNA promoter establishes a persistently open state to facilitate rapid reinitiation and perhaps also to bypass TFIIH-dependent promoter melting; this open state would then be disassembled to allow metaphase chromatin condensation. PMID:18378697

Passage of infectious nuclear polyhedrosis virus through the alimentary tracts of two small mammal predators of the gypsy moth, Lymantria dispar

Treesearch

R.A. Lautenschlager; J.D. Podgwaite

1977-01-01

The white-footed mouse, Peromyscus leucopus Rafinesque, and the short-tailed shrew, Blarina brevicauda Say, 2 small mammal predators of the gypsy moth, have demonstrated the ability to pass significant amounts of infectious nuclear polyhedrosis virus (NPV) through their alimentary tracts. Ninety-five percent of the gypsy moth...

Deterring War or Courting Disaster: An Analysis of Nuclear Weapons in the Indian Ocean

DTIC Science & Technology

2015-03-01

16 II. DETERRING WAR BETWEEN THE U.S. AND U.S.S.R. ...................................17 A. DETERRENCE THEORY AND THE...thesis will show, the literature and theory developed around the Cold War does not accommodate the relatively small size and relative inexperience of...and theory regarding sea-based nuclear weapons. Close examination of the Indian Ocean rivalries and the assumptions underpinning the belief in

Nuclear threats from small states

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

Kahan, J.H.

1994-06-13

What are the policy implications regarding proliferation and counter proliferation of nuclear weapons among Third World states. How does deterrence operate outside the parameters of superpower confrontation as defined by the cold war elaborate system of constraints enforced by concepts like mutual assured destruction, and counter-value and counter-force targeting. How can US policymakers devise contingencies for dealing with nuclear threats posed by countries like North Korea, Libya, Iraq, Iran, and Syria. These are some of the unsettling but nevertheless important questions addressed by the author in this monograph. In his analysis, Mr. Jerome Kahan examines the likelihood that one ormore » more of these countries will use nuclear weapons before the year 2000. He also offers a framework that policymakers and planners might use in assessing US interests in preempting the use of nuclear weapons or in retaliating for their use. Ironically, with the end of the cold war, it is imperative that defense strategists, policymakers, and military professionals think about the `unthinkable`. In the interest of fostering debate on this important subject, the Strategic Studies Institute commends this insightful monograph.« less

The Storage, Transportation, and Disposal of Nuclear Waste

NASA Astrophysics Data System (ADS)

Younker, J. L.

2002-12-01

The U.S. Congress established a comprehensive federal policy to dispose of wastes from nuclear reactors and defense facilities, centered on deep geologic disposal of high-level radioactive waste. Site screening led to selection of three potential sites and in 1987, Congress directed the Secretary of Energy to characterize only one site: Yucca Mountain in Nevada. For more than 20 years, teams of scientists and engineers have been evaluating the potential suitability of the site. On the basis of their work, the U.S. Secretary of Energy, Spencer Abraham, concluded in February 2002 that a safe repository can be sited at Yucca Mountain. On July 23, 2002, President Bush signed Joint Resolution 87 approving the site at Yucca Mountain for development of a repository, which allows the U.S. Department of Energy (DOE) to prepare and submit a license application to the U.S. Nuclear Regulatory Commission (NRC). Concerns have been raised relative to the safe transportation of nuclear materials. The U.S. history of transportation of nuclear materials demonstrates that high-level nuclear materials can be safely transported. Since the 1960s, over 1.6 million miles have been traveled by more than 2,700 spent nuclear fuel shipments, and there has never been an accident severe enough to cause a release of radioactive materials. The DOE will use NRC-certified casks that must be able to withstand very stringent tests. The same design features that allow the casks to survive severe accidents also limit their vulnerability to sabotage. In addition, the NRC will approve all shipping routes and security plans. With regard to long-term safety, the Yucca Mountain disposal system has five key attributes. First, the arid climate and geology of Yucca Mountain combine to ensure that limited water will enter the emplacement tunnels. Second, the DOE has designed a waste package and drip shield that are expected to have very long lifetimes in the repository environment. Third, waste form

75 FR 6223 - PSEG Nuclear LLC; Hope Creek Generating Station and Salem Nuclear Generating Station, Unit Nos. 1...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-08

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-272, 50-311 and 50-354; NRC-2010-0043] PSEG Nuclear LLC; Hope Creek Generating Station and Salem Nuclear Generating Station, Unit Nos. 1 and 2; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an Exemption, pursuant...

Can Sisyphus succeed? Getting U.S. high-level nuclear waste into a geological repository.

PubMed

North, D Warner

2013-01-01

The U.S. government has the obligation of managing the high-level radioactive waste from its defense activities and also, under existing law, from civilian nuclear power generation. This obligation is not being met. The January 2012 Final Report from the Blue Ribbon Commission on America's Nuclear Future provides commendable guidance but little that is new. The author, who served on the federal Nuclear Waste Technical Review Board from 1989 to 1994 and subsequently on the Board on Radioactive Waste Management of the National Research Council from 1994 to 1999, provides a perspective both on the Commission's recommendations and a potential path toward progress in meeting the federal obligation. By analogy to Sisyphus of Greek mythology, our nation needs to find a way to roll the rock to the top of the hill and have it stay there, rather than continuing to roll back down again. © 2012 Society for Risk Analysis.

Functional organization of the Sm core in the crystal structure of human U1 snRNP.

PubMed

Weber, Gert; Trowitzsch, Simon; Kastner, Berthold; Lührmann, Reinhard; Wahl, Markus C

2010-12-15

U1 small nuclear ribonucleoprotein (snRNP) recognizes the 5'-splice site early during spliceosome assembly. It represents a prototype spliceosomal subunit containing a paradigmatic Sm core RNP. The crystal structure of human U1 snRNP obtained from natively purified material by in situ limited proteolysis at 4.4 Å resolution reveals how the seven Sm proteins, each recognize one nucleotide of the Sm site RNA using their Sm1 and Sm2 motifs. Proteins D1 and D2 guide the snRNA into and out of the Sm ring, and proteins F and E mediate a direct interaction between the Sm site termini. Terminal extensions of proteins D1, D2 and B/B', and extended internal loops in D2 and B/B' support a four-way RNA junction and a 3'-terminal stem-loop on opposite sides of the Sm core RNP, respectively. On a higher organizational level, the core RNP presents multiple attachment sites for the U1-specific 70K protein. The intricate, multi-layered interplay of proteins and RNA rationalizes the hierarchical assembly of U snRNPs in vitro and in vivo.

Density functional theory calculations of UO2 oxidation: evolution of UO(2+x), U4O(9-y), U3O7, and U3O8.

PubMed

Andersson, D A; Baldinozzi, G; Desgranges, L; Conradson, D R; Conradson, S D

2013-03-04

Formation of hyperstoichiometric uranium dioxide, UO2+x, derived from the fluorite structure was investigated by means of density functional theory (DFT) calculations. Oxidation was modeled by adding oxygen atoms to UO2 fluorite supercells. For each compound ab initio molecular dynamics simulations were performed to allow the ions to optimize their local geometry. A similar approach was used for studying the reduction of U3O8. In agreement with the experimental phase diagram we identify stable line compounds at the U4O9-y and U3O7 stoichiometries. Although the transition from fluorite to the layered U3O8 structure occurs at U3O7 (UO2.333) or U3O7.333 (UO2.444), our calculated low temperature phase diagram indicates that the fluorite derived compounds are favored up to UO2.5, that is, as long as the charge-compensation for adding oxygen atoms occurs via formation of U(5+) ions, after which the U3O8-y phase becomes more stable. The most stable fluorite UO2+x phases at low temperature (0 K) are based on ordering of split quad-interstitial oxygen clusters. Most existing crystallographic models of U4O9 and U3O7, however, apply the cuboctahedral cluster. To better understand these discrepancies, the new structural models are analyzed in terms of existing neutron diffraction data. DFT calculations were also performed on the experimental cuboctahedral based U4O9-y structure, which enable comparisons between the properties of this phase with the quad-interstitial ones in detail.

Successful Recovery of Nuclear Protein-Coding Genes from Small Insects in Museums Using Illumina Sequencing.

PubMed

Kanda, Kojun; Pflug, James M; Sproul, John S; Dasenko, Mark A; Maddison, David R

2015-01-01

In this paper we explore high-throughput Illumina sequencing of nuclear protein-coding, ribosomal, and mitochondrial genes in small, dried insects stored in natural history collections. We sequenced one tenebrionid beetle and 12 carabid beetles ranging in size from 3.7 to 9.7 mm in length that have been stored in various museums for 4 to 84 years. Although we chose a number of old, small specimens for which we expected low sequence recovery, we successfully recovered at least some low-copy nuclear protein-coding genes from all specimens. For example, in one 56-year-old beetle, 4.4 mm in length, our de novo assembly recovered about 63% of approximately 41,900 nucleotides in a target suite of 67 nuclear protein-coding gene fragments, and 70% using a reference-based assembly. Even in the least successfully sequenced carabid specimen, reference-based assembly yielded fragments that were at least 50% of the target length for 34 of 67 nuclear protein-coding gene fragments. Exploration of alternative references for reference-based assembly revealed few signs of bias created by the reference. For all specimens we recovered almost complete copies of ribosomal and mitochondrial genes. We verified the general accuracy of the sequences through comparisons with sequences obtained from PCR and Sanger sequencing, including of conspecific, fresh specimens, and through phylogenetic analysis that tested the placement of sequences in predicted regions. A few possible inaccuracies in the sequences were detected, but these rarely affected the phylogenetic placement of the samples. Although our sample sizes are low, an exploratory regression study suggests that the dominant factor in predicting success at recovering nuclear protein-coding genes is a high number of Illumina reads, with success at PCR of COI and killing by immersion in ethanol being secondary factors; in analyses of only high-read samples, the primary significant explanatory variable was body length, with small beetles

Successful Recovery of Nuclear Protein-Coding Genes from Small Insects in Museums Using Illumina Sequencing

PubMed Central

Dasenko, Mark A.

2015-01-01

In this paper we explore high-throughput Illumina sequencing of nuclear protein-coding, ribosomal, and mitochondrial genes in small, dried insects stored in natural history collections. We sequenced one tenebrionid beetle and 12 carabid beetles ranging in size from 3.7 to 9.7 mm in length that have been stored in various museums for 4 to 84 years. Although we chose a number of old, small specimens for which we expected low sequence recovery, we successfully recovered at least some low-copy nuclear protein-coding genes from all specimens. For example, in one 56-year-old beetle, 4.4 mm in length, our de novo assembly recovered about 63% of approximately 41,900 nucleotides in a target suite of 67 nuclear protein-coding gene fragments, and 70% using a reference-based assembly. Even in the least successfully sequenced carabid specimen, reference-based assembly yielded fragments that were at least 50% of the target length for 34 of 67 nuclear protein-coding gene fragments. Exploration of alternative references for reference-based assembly revealed few signs of bias created by the reference. For all specimens we recovered almost complete copies of ribosomal and mitochondrial genes. We verified the general accuracy of the sequences through comparisons with sequences obtained from PCR and Sanger sequencing, including of conspecific, fresh specimens, and through phylogenetic analysis that tested the placement of sequences in predicted regions. A few possible inaccuracies in the sequences were detected, but these rarely affected the phylogenetic placement of the samples. Although our sample sizes are low, an exploratory regression study suggests that the dominant factor in predicting success at recovering nuclear protein-coding genes is a high number of Illumina reads, with success at PCR of COI and killing by immersion in ethanol being secondary factors; in analyses of only high-read samples, the primary significant explanatory variable was body length, with small beetles

Recruitment of phosphorylated small heat shock protein Hsp27 to nuclear speckles without stress

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

Bryantsev, A.L.; Chechenova, M.B.; Shelden, E.A.

During stress, the mammalian small heat shock protein Hsp27 enters cell nuclei. The present study examines the requirements for entry of Hsp27 into nuclei of normal rat kidney (NRK) renal epithelial cells, and for its interactions with specific nuclear structures. We find that phosphorylation of Hsp27 is necessary for the efficient entry into nuclei during heat shock but not sufficient for efficient nuclear entry under control conditions. We further report that Hsp27 is recruited to an RNAse sensitive fraction of SC35 positive nuclear speckles, but not other intranuclear structures, in response to heat shock. Intriguingly, Hsp27 phosphorylation, in the absencemore » of stress, is sufficient for recruitment to speckles found in post-anaphase stage mitotic cells. Additionally, pseudophosphorylated Hsp27 fused to a nuclear localization peptide (NLS) is recruited to nuclear speckles in unstressed interphase cells, but wildtype and nonphosphorylatable Hsp27 NLS fusion proteins are not. The expression of NLS-Hsp27 mutants does not enhance colony forming abilities of cells subjected to severe heat shock, but does regulate nuclear speckle morphology. These data demonstrate that phosphorylation, but not stress, mediates Hsp27 recruitment to an RNAse soluble fraction of nuclear speckles and support a site-specific role for Hsp27 within the nucleus.« less

The ``Nuclear Renaissance'' and the Spread of Nuclear Weapons

NASA Astrophysics Data System (ADS)

Lyman, Edwin S.

2007-05-01

As interest grows around the world in nuclear power as an energy source that could help control greenhouse gas emissions, some have proclaimed the arrival of a ``nuclear renaissance.'' But can the increased risks of more nuclear power be managed? The political crisis surrounding Iran's pursuit of uranium enrichment has exposed weaknesses in the nuclear nonproliferation regime. Also, al Qaeda's declared interest in weapons of mass destruction raises the concern that terrorists could acquire nuclear weapons by stealing materials from poorly secured facilities. Growth of nuclear energy would require the construction of many additional uranium enrichment plants. And the generation of more spent nuclear fuel without a credible waste disposal strategy would increase political support for reprocessing, which separates large quantities of weapon-usable plutonium from spent fuel. There is little evidence that the various institutional arrangements and technical schemes proposed to mitigate the security risks of a major nuclear expansion would be effective. This talk will focus on the measures necessary to allow large-scale global growth of nuclear power without resulting in an unacceptably high risk of nuclear proliferation and nuclear terrorism, and will discuss the feasibility of such measures. <small>To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.OSS07.E1.2small>

Roles for herpes simplex virus type 1 U{sub L}34 and U{sub S}3 proteins in disrupting the nuclear lamina during herpes simplex virus type 1 egress

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

Bjerke, Susan L.; Roller, Richard J.

2006-04-10

Cells infected with wild type HSV-1 showed significant lamin A/C and lamin B rearrangement, while U{sub L}34-null virus-infected cells exhibited few changes in lamin localization, indicating that U{sub L}34 is necessary for lamin disruption. During HSV infection, U{sub S}3 limited the development of disruptions in the lamina, since cells infected with a U{sub S}3-null virus developed large perforations in the lamin layer. U{sub S}3 regulation of lamin disruption does not correlate with the induction of apoptosis. Expression of either U{sub L}34 or U{sub S}3 proteins alone disrupted lamin A/C and lamin B localization. Expression of U{sub L}34 and U{sub S}3more » together had little effect on lamin A/C localization, suggesting a regulatory interaction between the two proteins. The data presented in this paper argue for crucial roles for both U{sub L}34 and U{sub S}3 in regulating the state of the nuclear lamina during viral infection.« less

7 CFR 51.3197 - U.S. No. 2.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 2. 51.3197 Section 51.3197 Agriculture... Standards for Grades of Bermuda-Granex-Grano Type Onions Grades § 51.3197 U.S. No. 2. U.S. No. 2 consists of...) Free from serious damage caused by: (1) Seedstems; (2) Dry sunken areas; (3) Sprouting; (4) Staining...

7 CFR 51.3197 - U.S. No. 2.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 2. 51.3197 Section 51.3197 Agriculture... Standards for Grades of Bermuda-Granex-Grano Type Onions Grades § 51.3197 U.S. No. 2. U.S. No. 2 consists of...) Free from serious damage caused by: (1) Seedstems; (2) Dry sunken areas; (3) Sprouting; (4) Staining...

7 CFR 51.3197 - U.S. No. 2.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 2. 51.3197 Section 51.3197 Agriculture... Standards for Grades of Bermuda-Granex-Grano Type Onions Grades § 51.3197 U.S. No. 2. U.S. No. 2 consists of...) Free from serious damage caused by: (1) Seedstems; (2) Dry sunken areas; (3) Sprouting; (4) Staining...

33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude 27°50...

Spent Nuclear Fuel

EIA Publications

2015-01-01

Spent nuclear fuel data are collected by the U.S. Energy Information Administration (EIA) for the Department of Energy's Office of Standard Contract Management (Office of the General Counsel) on the Form GC-859, "Nuclear Fuel Data Survey." The data include detailed characteristics of spent nuclear fuel discharged from commercial U.S. nuclear power plants and currently stored at commercial sites in the United States. Utilities were not required to report spent nuclear fuel assemblies shipped to away-from-reactor, off-site facilities.

Assessing Hubbard-corrected AM05+ U and PBEsol+ U density functionals for strongly correlated oxides CeO 2 and Ce 2O 3

DOE PAGES

Weck, Philippe F.; Kim, Eunja

2016-09-12

The structure–property relationships of bulk CeO 2 and Ce 2O 3 have been investigated using AM05 and PBEsol exchange–correlation functionals within the frameworks of Hubbard-corrected density functional theory (DFT+ U) and density functional perturbation theory (DFPT+ U). Compared with conventional PBE+ U, RPBE+ U, PW91+ U and LDA+ U functionals, AM05+ U and PBEsol+ U describe experimental crystalline parameters and properties of CeO 2 and Ce 2O 3 with superior accuracy, especially when + U is chosen close to its value derived by the linear-response approach. Lastly, the present findings call for a reexamination of some of the problematic oxidemore » materials featuring strong f- and d-electron correlation using AM05+ U and PBEsol+ U.« less

Assessing Hubbard-corrected AM05+ U and PBEsol+ U density functionals for strongly correlated oxides CeO 2 and Ce 2O 3

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

Weck, Philippe F.; Kim, Eunja

The structure–property relationships of bulk CeO 2 and Ce 2O 3 have been investigated using AM05 and PBEsol exchange–correlation functionals within the frameworks of Hubbard-corrected density functional theory (DFT+ U) and density functional perturbation theory (DFPT+ U). Compared with conventional PBE+ U, RPBE+ U, PW91+ U and LDA+ U functionals, AM05+ U and PBEsol+ U describe experimental crystalline parameters and properties of CeO 2 and Ce 2O 3 with superior accuracy, especially when + U is chosen close to its value derived by the linear-response approach. Lastly, the present findings call for a reexamination of some of the problematic oxidemore » materials featuring strong f- and d-electron correlation using AM05+ U and PBEsol+ U.« less

Thermodynamics of La and U and the separation factor of U/La in fused Me(Ga-40 wt.% In)/3LiCl-2KCl system

NASA Astrophysics Data System (ADS)

Smolenski, Valeri; Novoselova, Alena; Volkovich, Vladimir A.

2017-11-01

Separation of lanthanides and actinides can be achieved in a unique "molten chloride - liquid metal" system. Electrode potentials were recorded vs. Cl-/Cl2 reference electrode and the temperature dependencies of the apparent standard potentials of La-(Ga-In) and U-(Ga-In) alloys were determined. Thermodynamic properties and separation factor of lanthanum and uranium were calculated. The obtained data show the perspective for using this system in future innovation method for recovery of nuclear waste.

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

Compact toroid injection into C-2U

NASA Astrophysics Data System (ADS)

Roche, Thomas; Gota, H.; Garate, E.; Asai, T.; Matsumoto, T.; Sekiguchi, J.; Putvinski, S.; Allfrey, I.; Beall, M.; Cordero, M.; Granstedt, E.; Kinley, J.; Morehouse, M.; Sheftman, D.; Valentine, T.; Waggoner, W.; the TAE Team

2015-11-01

Sustainment of an advanced neutral beam-driven FRC for a period in excess of 5 ms is the primary goal of the C-2U machine at Tri Alpha Energy. In addition, a criteria for long-term global sustainment of any magnetically confined fusion reactor is particle refueling. To this end, a magnetized coaxial plasma-gun has been developed. Compact toroids (CT) are to be injected perpendicular to the axial magnetic field of C-2U. To simulate this environment, an experimental test-stand has been constructed. A transverse magnetic field of B ~ 1 kG is established (comparable to the C-2U axial field) and CTs are fired across it. As a minimal requirement, the CT must have energy density greater than that of the magnetic field it is to penetrate, i.e., 1/2 ρv2 >=B2 / 2μ0 . This criteria is easily met and indeed the CTs traverse the test-stand field. A preliminary experiment on C-2U shows the CT also capable of penetrating into FRC plasmas and refueling is observed resulting in a 20 - 30% increase in total particle number per single-pulsed CT injection. Results from test-stand and C-2U experiments will be presented.

AN ULTRA-LOW-MASS AND SMALL-RADIUS COMPACT OBJECT IN 4U 1746-37?

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

Li, Zhaosheng; Qu, Zhijie; Guo, Yanjun

Photospheric radius expansion (PRE) bursts have already been used to constrain the masses and radii of neutron stars. RXTE observed three PRE bursts in 4U 1746-37, all with low touchdown fluxes. We discuss here the possibility of a low-mass neutron star in 4U 1746-37 because the Eddington luminosity depends on stellar mass. With typical values of hydrogen mass fraction and color correction factor, a Monte Carlo simulation was applied to constrain the mass and radius of a neutron star in 4U 1746-37. 4U 1746-37 has a high inclination angle. Two geometric effects, the reflection of the far-side accretion disk andmore » the obscuration of the near-side accretion disk, have also been included in the mass and radius constraints of 4U 1746-37. If the reflection of the far-side accretion disk is accounted for, a low-mass compact object (mass of 0.41 ± 0.14 M {sub ☉} and radius of 8.73 ± 1.54 km at 68% confidence) exists in 4U 1746-37. If another effect operated, 4U 1746-37 may contain an ultra-low-mass and small-radius object (M = 0.21 ± 0.06 M {sub ☉}, R = 6.26 ± 0.99 km at 68% confidence). Combining all possibilities, the mass of 4U 1746-37 is 0.41{sub −0.30}{sup +0.70} M{sub ⊙} at 99.7% confidence. For such low-mass neutron stars, it could be reproduced by a self-bound compact star, i.e., a quark star or quark-cluster star.« less

Novel Humoral Prognostic Markers in Small-Cell Lung Carcinoma: A Prospective Study

PubMed Central

Gozzard, Paul; Chapman, Caroline; Vincent, Angela; Lang, Bethan; Maddison, Paul

2015-01-01

Purpose Favourable small cell lung carcinoma (SCLC) survival outcomes have been reported in patients with paraneoplastic neurological disorders (PNDs) associated with neuronal antibodies (Neur-Abs), but the presence of a PND might have expedited diagnosis. Our aim was to establish whether neuronal antibodies, independent of clinical neurological features, correlate with SCLC survival. Experimental Design 262 consecutive SCLC patients were examined: of these, 24 with neurological disease were excluded from this study. The remaining 238 were tested for a broad array of Neur-Abs at the time of cancer diagnosis; survival time was established from follow-up clinical data. Results Median survival of the non-PND cohort (n = 238) was 9.5 months. 103 patients (43%) had one or more antigen-defined Neur-Abs. We found significantly longer median survival in 23 patients (10%) with HuD/anti-neuronal nuclear antibody type 1 (ANNA-1, 13.0 months P = 0.037), but not with any of the other antigen-defined antibodies, including the PND-related SOX2 (n = 56, 24%). An additional 28 patients (12%) had uncharacterised anti-neuronal nuclear antibodies (ANNA-U); their median survival time was longer still (15.0 months, P = 0.0048), contrasting with the survival time in patients with non-neuronal anti-nuclear antibodies (detected using HEp-2 cells, n = 23 (10%), 9.25 months). In multivariate analyses, both ANNA-1 and ANNA-U independently reduced the mortality hazard by a ratio of 0.532 (P = 0.01) and 0.430 (P<0.001) respectively. Conclusions ANNAs, including the newly described ANNA-U, may be key components of the SCLC immunome and have a potential role in predicting SCLC survival; screening for them could add prognostic value that is similar in magnitude to that of limited staging at diagnosis. PMID:26606748

Measurements and analysis of leakage neutron spectra from multiple-slab sample assemblies comprising W,U,C, and CH2 with D-T neutron irradiation.