Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (5): 50602-050602.doi: 10.11889/j.0253-3219.2015.hjs.38.050602

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Impact analysis of criticality safety for 10-MWt solid thorium-based molten salt reactor spent nuclear fuel storage system

TIAN Jin1,2 XIA Xiaobin1 PENG Chao1,2 ZHANG Zhihong1,2   

  1. 1(Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China) 2(University of Chinese Academy of Sciences, Beijing 100049, China)
  • Received:2015-03-05 Revised:2015-03-16 Online:2015-05-10 Published:2015-05-08
  • Contact: XiaoBin Xia E-mail:xiaxiaobin@sinap.ac.cn

Abstract: Background: The 10-MWt TMSR-SF (Thorium-based Molten Salt Reactor-Solid Fuel) uses TRISO (Tri-structural isotropic) fuel and the fluoride salt is taken as a primary coolant. The molten salt could attach at the fuel element when the fuel was discharged from the core, which may consequently affect the reactivity of the spent nuclear fuel storage system. Purpose: This study aims to analyze the effects of the molten salt attached at the fuel element to the criticality safety of the spent nuclear fuel storage system. Methods: First of all, the TRITON (Transport Rigor Implemented with Time-dependent Operation for Neutronic depletion) module in SCALE was employed to calculate the burn-up results of the TRISO fuel in TMSR-SF reactor core, then in the premise of the maximum impregnated amount that the molten salt’s volume is 13.9% of the graphite’s volume, the criticality analysis of the spent nuclear fuel storage system was carried out by using MCNP code. Finally, the effects on the reactivity of spent fuel under conditions of molten salt infiltrated the fuel element and coated on the fuel element were compared separately. Results: Computational results showed that the reactivity in the situation that molten salt infiltrated the fuel element would be 5% greater than the molten salt coated the fuel surfaces, but is still in sub-criticality. The reactivity would be even smaller than that of the fuel elements contained only. Conclusion: Molten salt attached at the fuel element would affect the reactivity of the storage system, but the spent nuclear fuel storage system keeps in sub-criticality, which indicates the spent nuclear fuel storage system for TMSR-SF would remain in safety state.

Key words: TMSR, Spent nuclear fuel element, Molten salt infiltrate, Criticality calculation, Criticality safety analysis