Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2019, Vol. 30 ›› Issue (8): 125 doi: 10.1007/s41365-019-0650-y

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Application of global variance reduction method to calculate a high resolution fast neutron flux distribution for TMSR-SF1

Pu Yang1, 2 Ye Dai1 Yang Zou1 Rui Yan1 Bo Zhou1, 2 Shi-He Yu1 Yu-Wen Ma1   

  1. 1Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2019-01-10 Revised:2019-03-25 Accepted:2019-04-28
  • Contact: Yu-Wen Ma
  • Supported by:
    This work was supported by the Chinese TMSR Strategic Pioneer Science and Technology Project (No. XDA02010000) and the Frontier Science Key Program of Chinese Academy of Sciences (No. QYZDY-SSW-JSC016).
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Pu Yang, Ye Dai, Yang Zou, Rui Yan, Bo Zhou, Shi-He Yu, Yu-Wen Ma. Application of global variance reduction method to calculate a high resolution fast neutron flux distribution for TMSR-SF1.Nuclear Science and Techniques, 2019, 30(8): 125     doi: 10.1007/s41365-019-0650-y

Abstract: The solid fuel thorium molten salt reactor (TMSR-SF1) is a 10-MWth fluoride-cooled pebble bed reactor. As a new reactor concept, one of the major limiting factors to reactor lifetime is radiation-induced material damage. The fast neutron flux (E[0.1 MeV) can be used to assess possible radiation damage. Hence, a method for calculating high-resolution fast neutron flux distribution of the full-scale TMSR-SF1 reactor is required. In this study, a two-step subsection approach based on MCNP5 involving a global variance reduction method, referred to as forward-weighted consistent adjoint-driven importance sampling, was implemented to provide fast neutron flux distribution throughout the TMSR-SF1 facility. In addition, instead of using the general source specification cards, the user-provided SOURCE subroutine in MCNP5 source code was employed to implement a source biasing technique specialized for TMSR-SF1. In contrast to the one-step analog approach, the two-step subsection approach eliminates zero-scored mesh tally cells and obtains tally results with extremely uniform and low relative uncertainties. Furthermore, the maximum fast neutron fluxes of the main components in TMSR-SF1 are provided, which can be used for radiation damage assessment of the structural materials.

Key words: TMSR-SF1, Fast neutron flux, Global variance reduction, MCNP