Yuanzineng kexue jishu (May 2024)
Criticality Benchmarking Method of Core Physical Multi-group Constant Library Based on Solution Experiment
Abstract
The calculation of neutron physics in nuclear reactors is the most basic research content in the design and safety analysis of nuclear reactor systems, and the accuracy and confidence of the calculation results directly affect the evaluation of the safety and economy of nuclear reactors. The core physics multi-group constant library provides cross-section data and burn-up data for the calculation of neutron physics of nuclear reactors, which is the basis and guarantee of reactor physical calculation, and the accuracy of multi-group constant data in the core physics library directly affects the accuracy of reactor physical calculation and reactor design. At present, the international verification of multi-group constant library is usually carried out by simulating the critical experiments of the multi-group constant library coupling lattices calculation codes to be verified. The critical experiments in the International Handbook on Nuclear Criticality Safety (ICSBEP) are an important means to verify the accuracy and reliability of the nuclear library and neutron transport calculation codes, and the uranium and plutonium solution experiments with pure nuclide content and sensitive 1H/235U ratio under different spectral indexes in the ICSBEP are very suitable for verifying the data of the scattering cross section, the capture cross section of 1H, and the fission spectrum and absorption cross section of the 235U, 238U, 239Pu, 240Pu and other nuclide thermal energy points in the multi-group constant library. The critical experiments in ICSBEP are all three-dimensional experiments, and the two-dimensional modeling of the three-dimensional experimental setup is one of the keys to the verification of the multi-group constant library of core physics, and the accuracy of the model directly affects the accuracy of the verification results. Due to the limitations of the geometric processing method, the calculation code of each component cannot model the spherical device, so there is no benchmark method for the multi-group constant library based on the spherical critical benchmark experiments. In this paper, a modeling method for spherical experimental devices was proposed, which greatly increased the selection range of benchmark experiments used in critical benchmarking. At the same time, based on the international criticality safety benchmark evaluation project (ICSBEP2006), 49 uranium and plutonium solution experiments under different energy spectrum indicators were selected to conduct criticality benchmarking on the core physical multi-group constant library developed by China Nuclear Data Center (CNDC), and the reference results range of benchmark experiments under different energy spectrum indicators were given. The results of this paper can expand the scale and coverage of the benchmark of the core physical multi-group constant library, and help to further improve the accuracy of the high-fidelity core physical calculation codes.
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