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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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BREAKING NEWS: Trump issues executive orders to overhaul nuclear industry
The Trump administration issued four executive orders today aimed at boosting domestic nuclear deployment ahead of significant growth in projected energy demand in the coming decades.
During a live signing in the Oval Office, President Donald Trump called nuclear “a hot industry,” adding, “It’s a brilliant industry. [But] you’ve got to do it right. It’s become very safe and environmental.”
Tuomas Viitanen, Jaakko Leppänen
Nuclear Science and Engineering | Volume 180 | Number 2 | June 2015 | Pages 209-223
Technical Paper | doi.org/10.13182/NSE14-46
Articles are hosted by Taylor and Francis Online.
This paper discusses the generation of temperature majorant cross sections, the type of cross sections required by two separate techniques related to Monte Carlo neutron tracking, namely, the Doppler-broadening rejection correction (DBRC) and target motion sampling (TMS) temperature treatment methods. In the generation of these cross sections, the theoretically infinite range of thermal motion must be artificially limited by applying some sort of a cutoff condition, which affects both the accuracy and the performance of the calculations. In this paper, a revised approach for limiting thermal motion is first introduced, and then, optimal cutoff conditions are determined for both the traditional majorant, commonly used in DBRC implementations and old implementations of the TMS method, and the revised majorant. Using the revised type of temperature majorant cross sections increases the performance of the TMS method slightly, but no practical difference is observed with the DBRC method. It is also discovered that in ordinary reactor physical calculations, the cutoff conditions originally adopted from the SIGMA1 Doppler-broadening code can be significantly relieved without compromising the accuracy of the results. By updating the cutoff conditions for majorant generation, the CPU time requirement of Serpent 2.1.17 is reduced by 8% to 23% in TMS calculations and by 1% to 6% in problems involving DBRC.