Washington, DC) This meeting included updates from the funding agencies (DOE, NSF, ONR, and NASA) and a discussion panel amongst them, a review of the burning plasma study proposal, and a discussion of the HED study?s progress. Future work items such as the plasma physics volume of the decadal physics survey and potential studies on computer modeling and simulation were also discussed. Fall 2002: (September 28-29, 2002; Irvine, CA) This meeting discussed the status of the then-recently started burning plasma study, heard the findings and recommendations of the HED study, and discussed the prospects for fusion in light of the Snowmass summer study and the FESAC sub-panel on burning plasma program options. A science talk addressed the role of plasmas in astrophysics and brought attention to the need for greater rapport between plasma physicists and NASA's space sciences programs. The Plasma 2010 project was discussed in detail and a draft proposal was reviewed. Spring 2003: (April 4-5, 200; Washington, DC) This meeting centered on the activities of BPAC and discussion of the proposed Plasma 2010 project. Agency representatives discussed their program plans; they also commented on the possibilities of an ITER-future and discussed the status of the joint DOE/NSF funding program in basic plasma science. A presentation and a panel discussion addressed the loss of ONR funding in basic plasma science. The Plasma 2010 project was advanced to the stage of final proposal development. A science talk on inertial confinement fusion helped to balance the magnetic fusion emphasis of the meeting. Fall 2003: (September 27-28, 2003) At the fall 2003 meeting, the committee heard testimony from several speakers and further developed its plans for the Plasma 2010 project. Patric Muggli presented an overview of the goals and methods of the Coalition for Plasma Science. As co-chairs of the recently released final report of the Burning Plasma Assessment Committee, Ray Fonck and John Ahearne outlined their committee's key findings and recommendations for the committee. Jeff Hopwood presented a science talk on the current state of research in plasma microdischarges. The committee then took up a discussion of the Plasma 2010 committee and deliberated about the focus of the project. The committee tasked a subcommittee to develop draft wording that would reflect the need to identify the common themes of plasma science in the study. On the second day of the meeting, Mike Roberts presented an update by videoconference about the status of U.S. negotiations to participate in ITER. The committee then evaluated several emerging issues for future discussion and agreed to pursue the topics of scientific computing and low-temperature plasma physics at its next meeting. Spring 2004: (April 2-3, 2004) The committee discussed the federal program for plasma physics with representatives from DOE, NNSA, NSF, and NASA. It was learned that the budgets for this year and the next are squeezed from all directions, but agency program managers are doing the best they can. There appear to be significant opportunities emerging in the area of computing, including simulation and modeling, as identified in a science talk delivered by Bill Dorland. Charles Baker shared a status report about his FESAC priorities subpanel and Ed Thomas presented a summary of his subpanel's final report on plasma science and engineering workforce issues. Potential action items identified at this meeting include: following up with NASA/SEC to encourage participation in Plasma 2010, engaging the low temperature plasma and materials processing communities more effectively in committee activities, following up on the burning plasma program planning as it evolves, and brainstorming future activities of the committee ranging from workshops to letter reports to envisioning new studies.

This presentation is on the overview and status update of the Nuclear Criticality Safety Training and Pipeline Program. This lecture includes an introduction to the program, a program overview, and a status update at the end. Steps to complete moving forward are also provided.

IRSN (France), LLNL (USA) and ORNL (USA) began a long-term collaboration effort in 2015 to update the nuclear criticality Slide Rule (https://ncsp.llnl.gov/analytical-methods/criticality-sliderule) for the emergency response to a nuclear criticality accident. The Slide Rule permits the estimation of neutron and gamma dose rates and integrated doses based upon estimated fission yields, as a function of distance from the fission source, and time after criticality accidents for different critical systems. This paper presents the review of the section “estimation of the number of fissions”, named “fission yield” in the Slide Rule document. This estimation is important because the other information provided by the Slide Rule is directly proportional to the number of fissions. The previous models, based on Hansen and Barbry formulae, will be presented with their associated assumptions and limitations. Then, new proposals will be presented with a comparison to past criticality accidents and experimental data. The new formulae, based on the heat energy equation, cover many types of criticality accidents (solution, dry or low-moderated powder, rods/assemblies in water and dry metal) and require limited information in an emergency situation.

IRSN (France), LLNL (USA) and ORNL (USA) began a long-term collaboration effort in 2015 to update the nuclear criticality Slide Rule for the emergency response to a nuclear criticality accident. The Slide Rule permits the estimation of neutron and gamma dose rates and integrated doses based upon estimated fission yields, as a function of distance from the fission source, and time after criticality accidents for different critical systems. This paper presents results from the fourth phase of the current update of the Slide Rule project [1], in which delayed fission-product gamma (DFG) dose rates of unreflected plutonium critical systems were compared by several modern 3D radiation transport codes (MCNP, COG, SCALE), using updated flux-to-dose conversion factors. Dose rates are calculated for fissile material at five moderation ratios (H/Pu), at 1 m above the ground as a function of distance (between 30 cm and 1,200 m) from the external surface of the source to the center of the detector, and for periods between 1 s and 1,000 min after the critical instantaneous event. gamma source, by comparing the time-dependent energy spectra obtained from several methods. Overall, DFG dose rates calculated by each participant led to consistent results. Extra effort is under way to identify the cause of the remaining differences, by comparing precisely the gamma source, and particularly nuclides inventories.

As part of the nuclear data evaluation and validation cycle, the ENDF/B-VIII.0 cross-section library released in 2018 requires testing to determine areas of improvement and deterioration. Previous work by the authors investigated the performance of O-16, Fe-56, and Cu-63,Cu-65 cross sections, with this study acting as an extension of the prior work. In addition to the isotopes and nuclear criticality safety benchmarks of interest to the prior work, benchmarks from the International Criticality Safety Benchmark Evaluation Project Handbook were selected for their k(eff) sensitivity to H-1, C, Ni-58,Ni-60, W-182,W-183,W-184,W-186, U-235,U-238, or Pu-239 cross sections and were modeled in the SCALE code system maintained by Oak Ridge National Laboratory. In total, 253 benchmark configurations were selected for their sensitivities and modeled using SCALE 6.2.4 Criticality Safety Analysis Sequences (CSAS) continuous-energy Monte Carlo k(eff) calculations. This collection includes and expands upon the 99 benchmarks in the prior work. The AMPX-processed ENDF/B-VIII.0 library was decomposed into individual ENDF/B-VIII.0 datum libraries for each isotope of interest. Doing so allowed for the individual substitution of an ENDF/B-VIII.0 cross section in the place of ENDF/B-VII.1, determining isotope-specific effects of ENDF/B-VIII.0 relative to ENDF/B-VII.1. Full library calculations with entirely ENDF/B-VII.1 data or entirely ENDF/B-VIII.0 data were also executed. As a measure of performance, the average relative deviation was determined as the ratio of the deviation between calculated and experimental k(eff) to the propagated calculational and experimental uncertainty. With calculated full library and isotope-specific ENDF/B-VIII.0 k(eff)'s, an optimized combination of data libraries was estimated and confirmed with SCALE calculations. This showed that reverting Pu-239, Ni-58, O-16, and Cu-65 cross sections to ENDF/B-VII.1 resulted in improved performance relative to the full ENDF/B-VIII.0 library. Across all 253 benchmarks, the average relative deviation was 1.29 sigma for the full ENDF/B-VII.1 library, 1.17 sigma for the full ENDF/B-VIII.0 library, and 0.97 sigma for the optimized combination. The reversion of Pu-239, Ni-58, O-16, and Cu-65 cross sections to ENDF/B-VII.1 in the 99 benchmarks of the prior work resulted in further improved experimental agreement compared to the previously reported improvement from O-16 and Cu-65 alone. Therefore, it is suggested that applications with significant sensitivities to Pu-239, Ni-58, O-16, and Cu-65 consider their choice of nuclear data library.

Recently completed cross-section evaluations sponsored in part by the Nuclear Criticality Safety Program were incorporated into the 2018 release of the ENDF/B-VIII.0 cross-section library. Evaluated isotopes of interest to the nuclear data and criticality safety community include O-16, Fe-56, and Cu-63,Cu-65. For performance validation, benchmark models defined in the International Criticality Safety Benchmark Evaluation Project Handbook were selected based on energy-integrated k(eff) sensitivities to total cross sections of interest and compared with experimental values. Of the 102 benchmark configurations that were utilized, 63 are sensitive to O-16, 32 sensitive to Cu-63,Cu-65, and 25 sensitive to Fe-56. Selected benchmarks were modeled in SCALE 6.2.3 Criticality Safety Analysis Sequence (CSAS) continuous-energy Monte Carlo k(eff) calculations with ENDF/B-VII.1, with a hybrid ENDF/B-VII.1 with ENDF/B-VIII.0 data substituted for individual isotopes of interest, and with ENDF/B-VIII.0. ENDF/B-VIII.0 showed improved agreement with experimental k(eff) for Fe-56, Cu-63, elemental copper, and full library substitution while producing lessened agreement for O-16 and Cu-65. With full library and isotope-specific ENDF/B-VIII.0 performance, a best-case ENDF library was formed by excluding underperforming isotopes' ENDF/B-VIII.0 data, reverting O-16 and Cu-65 cross sections to ENDF/B-VII.1. This resulted in the average relative deviation between calculated and experimental data improving from 1.45 sigma for the ENDF/B-VIII.0 library to 1.32 sigma for the best-case library, relative to benchmark uncertainty.

This paper provides a high-level comparison between the international and domestic nuclear criticality safety (NCS) standards, as requested by members of the Nuclear Criticality Safety Division. Currently, there are 18 enacted American National Standards Institute (ANSI)/American National Standards (ANS) standards, and 1 ANSI/ANS standard, in progress. There are 11 NCS standards from the International Organization for Standardization (ISO), Technical Committee 85 (TC85) on Nuclear Energy, Subcommittee 5 (SC5) on Nuclear Fuel Cycle, Working Group 8 (WG8). NCS standard revisions are in progress for both standards organizations. The key differences between the ISO TC85/SC5/WG8 and ANSI/ANS-8 consensus NCS standards are summarized. The hard work done by the ANS-8 and WG8 volunteers allows for applicable, high-quality consensus standards for use by the NCS community. This paper defines the current status of each ANSI/ANS and ISO standard, the work in in progress, the revisions/amendments in progress, and WG8/ANS-8 non-standard business in progress. A forthcoming paper will compare the development process for ISO and ANSI/ANS standards.

In the update from ENDF/B-VII.1 to ENDF/B-VIII.0, copper cross sections were significantly altered in the intermediate and fast spectrum of the ENDF-VIII.0 library. Performance of this ENDF data requires validation to determine whether recent evaluation has proven beneficial. To examine the performance of the new library, particularly new copper data, critical benchmarks from the ICSBEP handbook were chosen for their sensitivity to copper cross section changes and modeled using SCALE continuous energy Monte Carlo simulations. Selected benchmarks were modeled in ENDF-VII.1 and ENDF-VIII.0 to compute keff within a statistical uncertainty of 10 pcm and compared in reference to the benchmark experimental criticality. Due to spectrum choices in selection based on the changes to cross section data, the set of benchmarks consist of intermediately enriched uranium, highly enriched uranium, or plutonium systems. 11 separate benchmark evaluations containing 32 individual configurations highly sensitive to copper were selected, modelled, and compared to benchmark experimental criticality. This work demonstrates a significant decrease in the deviation between calculated and experimental criticality as a result of the ENDF-VIII.0 library; a decrease in absolute mean deviation from 522.5±39.3 to 249.6±39.3, and a decrease in root mean square deviation from 630.8±46.1 to 338.1±74.9. Additionally, the role of recently evaluated copper data in this improved agreement is presented, confirming the benefit of reaffirming cross section data.

Topics for the meeting were as follows: Safety Minute, High-level Overview of NCRTS, Overview of NCRTS Groups (Radiation Transport, Nuclear Data, and Nuclear Criticality Safety), and Question and Answer.

affect neutron multiplication.” This training is performed to ensure NCS, and operations staff are aware of the risks involved with conducting operations with fissionable materials outside reactors.