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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Current Status of Helium-3 Alternative Technologies for Nuclear Safeguards

International safeguards inspectorates (e.g., International Atomic Energy Agency {IAEA}, or Euratom) rely heavily on neutron assay techniques, and in particular, on coincidence counters for the verification of declared nuclear materials under safeguards and for monitoring purposes. While 3 He was readily available, the reliability, safety, ease of use, gamma-ray insensitivity, and high intrinsic thermal neutron detection efficiency of 3 He-based detectors obviated the need for alternative detector technologies. However, the recent decline of the 3 He gas supply has triggered international efforts to develop and field neutron detectors that make use of alternative materials. In response to this global effort, the U.S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) and Euratom launched a joint effort aimed at bringing together international experts, technology users and developers in the field of nuclear safeguards to discuss and evaluate the proposed 3 He alternative materials and technologies. The effort involved a series of two workshops focused on detailed overviews and viability assessments of various 3 He alternative technologies for use in nuclear safeguards applications. The key objective was to provide a platform for collaborative discussions and technical presentations organized in a compact, workshop-like format to stimulate interactions among the participants. The meetings culminated in a benchmark exercise providing a unique opportunity for the first inter-comparison of several available alternative technologies. This report provides an overview of the alternative technology efforts presented during the two workshops along with a summary of the benchmarking activities and results. The workshop recommendations and key consensus observations are discussed in the report, and used to outline a proposed path forward and future needs foreseeable in the area of 3 He-alternative technologies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Plutonium measurements with a fast-neutron multiplicity counter for nuclear safeguards applications

Measurements were performed at the Joint Research Centre in Ispra, Italy to field test a fast-neutron multiplicity counter developed at the University of Michigan. The measurements allowed the assessment of the system's photon discrimination abilities, efficiency when measuring neutron multiplicity, ability to characterize 240 Pu eff mass, and performance relative to a currently deployed neutron coincidence counter. We describe how this work is motivated by the need to replace and improve upon 3 He neutron detection systems for nuclear safeguards applications.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene and 1-chloro-3-buten-2-one, two alternative metabolites of 1,3-butadiene

The cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene (CHB), a known in vitro metabolite of the human carcinogen 1,3-butadiene, have not previously been investigated. Because CHB can be bioactivated by alcohol dehydrogenases to yield 1-chloro-3-buten-2-one (CBO), a bifunctional alkylating agent that caused globin-chain cross-links in erythrocytes, in the present study we investigated the cytotoxic and genotoxic potential of CHB and CBO in human normal hepatocyte L02 cells using the MTT assay, the relative cloning efficiency assay and the comet assay. We also investigated the mutagenic potential of these compounds with the Ames test using Salmonella strains TA1535 and TA1537. The results provide clear evidence for CHB and CBO being both cytotoxic and genotoxic with CBO being approximately 100-fold more potent than CHB. Interestingly, CHB generated both single-strand breaks and alkali-labile sites on DNA, whereas CBO produced only alkali-labile sites. CHB did not directly result in DNA breaks, whereas CBO was capable of directly generating breaks on DNA. Interestingly, both compounds did not induce DNA cross-links as examined by the comet assay. The Ames test results showed that CHB induced point mutation but not frameshift mutation, whereas the toxic effects of CBO made it difficult to reliably assess the mutagenic potential of CBO in the two strains. Collectively, the results suggest that CHB and CBO may play a role in the mutagenicity and carcinogenicity of 1,3-butadiene. - Highlights: • 1-Chloro-2-hydroxy-3-butene (CHB) is cytotoxic and genotoxic in human liver cells. • The CHB metabolite, 1-chloro-3-buten-2-one (CBO) is ∼ 100-fold more toxic than CHB. • CHB and CBO cause DNA alkali-labile sites, but only CBO directly causes DNA breaks. • CHB is mutagenic in the Ames test, but CBO is too toxic in the assay. • The results suggest a role for CHB in 1,3-butadiene genotoxicity and mutagenicity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Boron-10 Based Neutron Coincidence Counter for Safeguards

The shortage of 3He has triggered the search for effective alternative neutron detection technologies for national security applications, including international nuclear safeguards. Any alternative neutron detection technology must satisfy two basic criteria: it must meet a neutron detection efficiency requirement, and it must be insensitive to gamma-ray interference at a prescribed level while still meeting the neutron detection requirement. For nuclear safeguards, a system must perform measurements in the field with a prescribed precision in a specified time. This paper describes an effort to design, model and test an alternatives-based neutron coincidence counter for nuclear safeguards applications. The technology chosen for use in an alternatives-based uranium neutron coincidence collar was boron-lined proportional counters. Extensive modeling was performed of various system configurations and comparisons were made to measurements on a commercial prototype boron-10 based uranium neutron coincidence collar.

alternative neutron detectors↗
DOE OSTI2013

Boron-10 ABUNCL Active Testing

The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3 He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10 B-lined proportional tubes in a configuration typical for 3 He-based coincidence counter applications. This report provides results from testing of the active mode of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) at Los Alamos National Laboratory using sources and fuel pins.

Boron Based Detector↗
DOE OSTI2013

Final Technical Report for the Neutron Detection without Helium-3 Project

This report details the results of the research and development work accomplished for the ‘Neutron Detection without Helium-3’ project conducted during the 2011-2013 fiscal years. The primary focus of the project was to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but were outside the scope of this study.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1983

Ordered pairing in liquid metallic hydrogen

We study two possible types of pairing involving the protons of a proposed low-temperature liquid phase metallic hydrogen. Electron-proton pairing, which can result in an insulating phase, is investigated by using an approximate solution of an Eliashberg-type equation for the anomalous self-energy. A very low estimate of the transition temperature is obtained by including proton correlations in the effective interaction. For proton-proton pairing, we derive a new proton pair potential based on the Abrikosov wave function. This potential includes the electron-proton interaction to all orders and has a much larger well depth than is obtained with linear screening methods. This suggests the possibility of either a superfluid paired phase analogous to that in He-3, or alternatively a phase with true molecular pairing.

Carlsson, A. E.↗
NASA NTRS1946

Tank Tests of an Alternate Hull Form for the Consolidated Vultee PB2Y-3 Airplane

Tests have been made in Langley tank no. I of a dynamic model of the Consolidated Vultee PB2Y-3 airplane. These tests were made using an alternate hull form, the purpose of which was to reduce the bow spray and eliminate the landing instability which are objectionable features of the production design. The major differences from the PB2Y-3 hull included a deeper step to improve the landing stability , and a lengthened forebody and increased beam to reduce the sway in the propellers and on the flaps. The tests showed that the spray characteristics of the revised hull form were much better than that ot the production design. In addition the take-off and landing stability of the model with the alternate hull were satisfactory.

Land, Norman S.↗
DOE OSTI2015

Scintilla European project, the successful research results

The Scintilla FP7 project is ended in December 2014, the fruitful results of 3 years development and tests will be presented. SCINTILLA offers the capacity to finding a reliable alternative to Helium-3 based detection systems since the gas which is predominantly used in nuclear safeguards and security applications has now become very expensive, rare and nearly unavailable. SCINTILLA benchmarks results are based on international standards. Radiation Portal tests were carried out at the Joint Research Centre (JRC) in Ispra (Italy). The scintilla project addresses few mains issues. The first is to develop neutron detectors for Radiation Portal Monitor (RPM) and the second is the need of new wearable integrated solutions for Spectrometric Personal Radiation Monitor (SPRM). The partners which provide technical systems of the scintilla project are INFN-ANSALDO, CEA, SYMETRICA and SAPHYMO. For RPM, the objective is to find reliable alternatives to Helium-3 historical neutron detector and provide technical solutions which cope with tests for reliable mobile and cost effective. For Spectrometric Personal Radiation Monitor (SPRM), SCINTILLA is innovating in technology areas that offer complementary capabilities for detecting and identifying gamma, Two CZT (Cadmium Zinc Telluride) addressing contexts of used by first responder technologies, one is a wearable detector and the second is a gamma camera complemented by advanced image processing technologies. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Supplemental Structural Analyses Used in Support of Certification of the Defense Programs Package 3

The Defense Programs Package (DPP)-3 is to be certified by the National Nuclear Security Administration (NNSA) Packaging and Transportation Division (PTD). Certification is based on successful physical testing of the package, and six certification test units (CTUs) have been subjected to the normal conditions of transport (NCT) and hypothetical accident conditions (HAC) outlined in Title 10 of the Code of Federal Regulations Part 71 (10 CFR 71). During regulatory testing of one of the CTUs, the drum lid closure bolt closest to the impact surface failed during the HAC 30-ft side drop. One of the testing goals for this CTU was to minimize the thermal pathway from the drum exterior shell to the containment vessel (CV) flange and O-rings, leading to the maximum damage scenario in preparation for thermal testing at 1475 °F. Therefore, the puncture bar impact proceeded as originally planned by striking the side wall of the package exterior closest to the location of the CV flange. This puncture bar impact did not attempt to exploit the region of the failed drum lid closure bolt to potentially cause more damage to the package. After the conclusion of regulatory testing, the DPP-3 package finite element model was used to numerically evaluate the effects of puncture bar impacts to the drum exterior in the vicinity of the failed drum lid closure bolt to further demonstrate the robustness of the DPP-3 design. Three alternate puncture bar impact locations and orientations were evaluated to demonstrate that these puncture bar impacts would not substantially reduce the effectiveness of the DPP-3 packaging. This paper describes the supplemental finite element models performed and structural analysis results that demonstrate the alternate HAC 40-in. puncture bar impact tests would have no deleterious effect on the performance of the DPP-3.

Sakalaukus Jr., Peter J.↗
DOE OSTI2019

Structural Differences between Pri-miRNA Paralogs Promote Alternative Drosha Cleavage and Expand Target Repertoires

MicroRNA (miRNA) processing begins with Drosha cleavage, the fidelity of which is critical for downstream processing and mature miRNA target specificity. To understand how pri-miRNA sequence and structure influence Drosha cleavage, we studied the maturation of three pri-miR-9 paralogs, which encode the same mature miRNA but differ in the surrounding scaffold. Here, we show that pri-miR-9-1 has a unique Drosha cleavage profile due to its distorted and flexible stem structure. Cleavage of pri-miR-9-1, but not pri-miR-9-2 or pri-miR-9-3, generates an alternative miR-9 with a shifted seed sequence that expands the scope of its target RNAs. Analyses of low-grade glioma patient samples indicate that the alternative-miR-9 has a potential role in tumor progression. Furthermore, we provide evidence that distortion of pri-miRNA stems induced by asymmetric internal loops correlates with Drosha cleavage at non-canonical sites. Our studies reveal that pri-miRNA paralogs can have distinct functions via differential Drosha processing.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1976

The long-term intensity behavior of Centaurus X-3

In three years of observation, the X-ray source Cen X-3 appears to alternate between 'high states', with an intensity of 150 counts/s (2-6 keV) or greater, and 'low states', where the source is barely detectable. The time scale of this behavior is of the order of months, and no apparent periodicity has been observed. Analysis of two transitions between these states is reported. During two weeks in July 1972, the source increased from about 20 counts/s to 150 counts/s. The detailed nature of this turn-on is interpreted in terms of a model in which the supergiant's stellar wind decreases in density. A second transition, a turnoff in February 1973, is similarly analyzed and found to be consistent with a simple decrease in accretion rate. The presence of absorption dips during transitions at orbital phases 0.4-0.5 as well as at phase 0.75 is discussed. The data are consistent with a stellar-wind accretion model and with different kinds of extended lows caused by increased wind density masking the X-ray emission or by decreased wind density lowering the accretion rate.

Schreier, E. J.↗
NASA NTRS1987

Helium technology issues

A number of future space missions require liquid helium for cooling scientific payloads. These missions will require the long term storage and resupply of liquid helium at temperatures of 1.4 - 2.1 Kelvin. In addition, some of the proposed instruments will require refrigeration to temperatures as low as 50 mK. A variety of liquid helium based refrigerator systems could provide this subkelvin cooling. The status of helium storage and refrigeration technologies and of several alternative technologies is presented here along with areas where further research and development are needed. (Helium resupply technologies are the topic of another presentation at this symposium). The technologies covered include passive and dynamic liquid helium storage, alternatives to liquid helium storage, He -3 refrigerators, He -3/He -4 dilution refrigerators, and alternative sub-kelvin coolers.

Kittel, Peter↗
DOE OSTI2016

Corrosion Testing of Monofrax K-3 Refractory in Defense Waste Processing Facility (DWPF) Alternate Reductant Feeds

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) uses a combination of reductants and oxidants while converting high level waste (HLW) to a borosilicate waste form. A reducing flowsheet is maintained to retain radionuclides in their reduced oxidation states which promotes their incorporation into borosilicate glass. For the last 20 years of processing, the DWPF has used formic acid as the main reductant and nitric acid as the main oxidant. During reaction in the Chemical Process Cell (CPC), formate and formic acid release measurably significant H 2 gas which requires monitoring of certain vessel’s vapor spaces. A switch to a nitric acid-glycolic acid (NG) flowsheet from the nitric-formic (NF) flowsheet is desired as the NG flowsheet releases considerably less H 2 gas upon decomposition. This would greatly simplify DWPF processing from a safety standpoint as close monitoring of the H 2 gas concentration could become less critical. In terms of the waste glass melter vapor space flammability, the switch from the NF flowsheet to the NG flowsheet showed a reduction of H 2 gas production from the vitrification process as well. Due to the positive impact of the switch to glycolic acid determined on the flammability issues, evaluation of the other impacts of glycolic acid on the facility must be examined.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1984

Alternative gravity-assist sequences for the ISEE-3 escape trajectory

The International Sun-Earth Explorer-3 (ISEE-3) was moved from its mission halo orbit upstream of the earth's magnetosphere on June 10, 1982. Multiple lunar swingby maneuvers were then used to shape the trajectory for extensive exploration of the distant geomagnetic tail and finally to place the spacecraft on a course that will intercept the comet Giacobini-Zinner on September 11, 1985. With this new mission objective, the spacecraft was renamed the International Cometary Explorer (ICE). A double-lunar-swingby control technique involving five passes by the moon was eventually implemented to accomplish this, but in the process of finding this solution several feasible, though less optimal, alternative trajectory sequences implementing the same procedure were discovered. This paper provides a descriptive comparison of these very different orbital profiles and serves to illustrate the utility and great flexibility of this orbital control procedure. Targeting methodology for finding constrained solutions in this space is also presented.

Muhonen, D.↗
DOE OSTI2025

Benchmarking third-order cluster perturbation theory for electronically excited states

In this study, we investigate the reliability of cluster perturbation (CP) theory applied to the calculation of electronically excited states through a comprehensive benchmark. In CP theory, perturbative corrections are added to the properties of a parent excitation space, which converge toward the properties of a target excitation space. For the CPS(D-n) model, perturbative corrections through order n are added to the coupled cluster singles (CCS) excitation energies to target the coupled cluster singles and doubles (CCSD) excitation energies. Through a comparative analysis of excitation energy calculations across a diverse set of molecules and wavefunction methods, we present a comprehensive evaluation of the accuracy of the third-order CPS(D) model, CPS(D-3), in calculating excitation energies. Further, our findings demonstrate that CPS(D-3) is a reliable alternative to established methods, particularly CCSD, while systematically overestimating the excitation energies compared to high-level coupled cluster methods such as CC3. These results highlight the strengths and limitations of CPS(D-3), as well as the promising directions for its future development.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Pillar-structured neutron detector based multiplicity system

This work demonstrates the potential of silicon pillars filled with boron-10 as a sensor technology for a compact and portable neutron multiplicity system. Solid-state, semiconductor based neutron detectors may enable completely new detector form factors, offer an alternate approach to helium-3 based systems, and reduce detector weight and volume requirements. Thirty-two pillar-structured neutron detectors were assembled into a system with an active area of over 20 cm 2 and were used in this work to demonstrate the feasibility of this sensor technology as a potential replacement for helium-3 based gas detectors. Multiplicity measurements were successfully carried out using a californium-252 neutron source, in which the source mass, system efficiency, and die-away time were determined. As a result, this demonstration shows that these solid-state detectors could allow for a more compact and portable system that could be used for special nuclear material identification in the field.

42 ENGINEERING↗