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Latest News
In an international industry, regulators cross the border too
Since nuclear physics works the same in Ontario as it does in Tennessee, the industry has been trying to create a reactor that can be deployed on both sides of the border. Now, the Nuclear Regulatory Commission and the Canadian Nuclear Safety Commission have decided that some of their rulings can cross the border too.
Ilham Variansyah, Ryan G. McClarren
Nuclear Science and Engineering | Volume 196 | Number 11 | November 2022 | Pages 1280-1305
Technical Paper | doi.org/10.1080/00295639.2022.2091906
Articles are hosted by Taylor and Francis Online.
An extensive study of population control techniques (PCTs) for time-dependent and eigenvalue Monte Carlo (MC) neutron transport calculations is presented. We define PCT as a technique that takes a censused population and returns a controlled, unbiased population. A new perspective based on an abstraction of particle census and population control is explored, paving the way to improved understanding and application of the concepts. Five distinct PCTs identified from the literature are reviewed: simple sampling, splitting-roulette (SR), combing (CO), modified combing, and duplicate-discard (DD). A theoretical analysis of how much uncertainty is introduced to a population by each PCT is presented. Parallel algorithms for the PCTs, applicable for both time-dependent and eigenvalue MC simulations, are proposed. The relative performance of the PCTs based on run time and tally mean error or standard deviation is assessed by solving time-dependent and eigenvalue test problems. It is found that SR and CO are equally the most performing techniques, closely followed by DD.