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Nuclear Fuel Fabrication
Published in Kenneth D. Kok, Nuclear Engineering Handbook, 2016
Nuclear fuel cycle facilities are regulated by many state and federal agencies. In the United States, facilities are licensed by the Nuclear Regulatory Commission (NRC), under Title 10 of the Code of Federal Regulations, Part 70 (10 CFR 70), as special nuclear material facilities. In addition, facilities are required to have environmental and nuclear material permits. The NRC licenses fuel cycle facilities under the following federal regulations: 10 CFR Part 30—Rules of general applicability to domestic licensing of by-product material10 CFR Part 40—Domestic licensing of source material10 CFR Part 70—Domestic licensing of special nuclear material10 CFR Part 73—Physical protection of plants and materials10 CFR Part 74—Material control and accounting of special nuclear material
Analysis of Major Benchmark Uncertainties for Fast Metal Assemblies in the ICSBEP Handbook
Published in Nuclear Science and Engineering, 2023
Theresa Cutler, Kelsey Amundson, Jesson Hutchinson, Nick Thompson
Table V and Table VI summarize the mean, median, and max for each component type, for HMF and PMF, respectively. The min is not shown, as it is always zero. Units are uncertainty (pcm), except for the last column, which is the quantity of the applicable benchmark parameters. Figure 8 shows pie diagrams for component-type contribution to the total uncertainty. Fuel, reflector, and structural are the most important components for uncertainty in both HMF and PMF benchmarks, accounting for >75% of the total uncertainty. Both mean and median uncertainties are always larger for PMF series than HMF series, except for structural uncertainty median. For all categories except cladding and absorbers in the PMF series, means are larger than median values. It can be seen that structural has the greatest median contribution to uncertainty for HMF but least for PMF. Fuel has the largest mean for both series, which points to the importance of using well-characterized special nuclear material (i.e., HEU or plutonium).
Advancements in Yttrium Hydride Moderator Development
Published in Nuclear Technology, 2023
Holly Trellue, Chase Taylor, Erik Luther, Theresa Cutler, Aditya Shivprasad, J. Keith Jewell, Dasari V. Rao, Michael Davenport
The special nuclear material used was HEU metal discs known as C-discs. The discs were unclad. There were six total, with an average mass of 3920 g and an average enrichment of 93.1 wt% 235U. The axial reflectors included Be and depleted uranium discs. Electric aluminum oxide heaters with NiCrome heating elements were used to heat a central region (which included HEU and YHx) significantly more than the rest of the assembly, thus minimizing competing effects. These heaters were manufactured to be slim and used materials that did not have the potential to complicate the results. The heaters were a coil with alumina shells on the top and bottom. A picture of each is shown in Fig. 8. Graphite plates were also used throughout the assembly and had slots for resistance temperature detectors included in them so that the temperature could be monitored at multiple points continuously.
Nuclear Security Considerations for Space Nuclear Power: A Review of Past Programs with Recommendations for Future Criteria
Published in Nuclear Technology, 2020
According to a National Academy of Sciences (NAS) report, “Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors,”1 there are three “main civilian applications that use special nuclear material (primarily HEU)”: research reactors, targets for medical isotope production, and propulsion systems for remote missions.1 The NAS report defines a civilian research reactor as “a land-based reactor not connected to the grid” such that propulsion reactors (e.g., spacecraft, icebreakers, or naval vessels) are excluded. The NAS also excludes reactors with a sole military purpose with the exception of dual civilian military reactors. Per the NAS definition, U.S. naval reactors and NASA space reactors do not fall under the U.S. government policy program to reduce or eliminate the use of HEU in civilian research reactors. This is important to note since much of the U.S. policy to reduce or eliminate the use of HEU has been focused on civilian research reactors.