CENDL-3.2 and ENDF/B-VIII.0 referring to the latest version of CENDL and ENDF/B, respectively, evaluated nuclear data library. To examine the applicability the libraries to high-temperature reactors (HTRs), the HTR-10 benchmark calculations are conducted by adopting CENDL-3.2, ENDF/B-VIII.0, and ENDF/B-VII.1 library. The calculated results are compared with the experimental results. As indicated from the comparison, the results of ENDF/B-VIII.0 show the optimal consistency with the experimental results, and CENDL-3.2 outperforms ENDF/B-VII.1. A semi-quantitative analysis method, on the basis of the sensitivity result, is employed to assess the effect of the cross-section change to keff. As revealed from the further calculations and analyses, the difference between cross-sections of C-12 (n, γ) channel primarily causes the inconsistent performance of CENDL-3.2 and ENDF/B-VIII.0 on the benchmark.
In the Monte Carlo algorithm, the power iteration method is commonly used to obtain the Fission Neutron Bank of each cycle. This method uses the offspring produced by the neutrons of the previous cycle as the next cycle’s fission neutron bank. Thus, there is physical continuity between the adjacent cycle’s fission source distributions (FSD). This physical continuity of this process will lead to the mathematical correlation of fission source distributions. We extensively investigate the correlation of fission source distributions using mathematical approaches. We analyzed the correlations of the FSD with different geometric scales and the adjacent number of cycles. The results show that the correlations between two fission source distributions decline with the adjacent cycle number increases. The miniature models would take dozes of cycles for the correlations to decline to be negligible, while the standard reactor core model would use around 500 cycles to decline. These correlations should be carefully removed if a non-bias Monte Carlo calculation is carried out. In the BEAVRS core model, the correlations would result in around 80 percent underestimating the variance for the flux tally of assemblies. These methods can be easily implemented in the standard Monte Carlo codes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.