Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (5): 50604-050604.doi: 10.11889/j.0253-3219.2020.hjs.43.050604

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Analysis of Th-U breeding in molten salt fast reactor

Dongguo LIU Guimin LI   

  1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
  • Received:2019-11-26 Revised:2020-03-10 Online:2020-05-15 Published:2020-05-07
  • Supported by:
    Strategic Priority Research Program of Chinese Academy of Sciences(XDA02010000);Frontier Science Key Program of Chinese Academy of Sciences(QYZDY-SSW-JSC016)

Abstract: Background

Because of its superior performance, molten salt reactor has been selected as one of the candidates for the fourth-generation reactors, and has become the focus of international attention.


In the molten salt fast neutron reactor, we try to find the most suitable molten salt fuel scheme to achieve the purpose of high proliferation of fissile nuclides.


Based on the two-fluid cooling cycle scheme, independent cooling cycles of fission molten salt fuel and breeding molten salt, a comprehensive simulation program SCALE (Standardized Computer Analyses for Licensing Evaluation) was employed to achieve high breeding ratio (BR) in the molten salt fast reactor by utilizing the high solubility characteristics of thorium and uranium heavy metal salts in fluorinated or chlorinated molten salts at high temperatures. Three feasible molten salt fuel schemes (LiF+ThF4+UF4, NaF+ThF4+UF4, and NaCl+ThCl3+UCl3) were compared by calculating the neutron energy spectrum and the reactivity temperature coefficient. Influence factors of BR, such as the sizes of fission zone, breeding zone and ZrC reflective layer, the isotopic abundance of 6Li and 35Cl in the molten salt, molten salt density error on the calculation accuracy, and the evolution of fissile nuclides with reactor operating time, were computationally analyzed.


The breeding ratio (BR) of reactor reaches about 1.2 in all three molten salt fuel schemes when the diameter and height of the fission zone are both 260 cm.


With optimization of the reactor geometry, and the composition and isotopic abundance of the molten salt fuel, a high breeding ratio of the reactor is achievable for the thorium-uranium fuel cycle of molten salt fast reactor.

Key words: Molten salt reactor, Fast neutron reactor, Breeder, Neutron physics, Thorium-uranium cycle, Breeding ratio

CLC Number: 

  • TL3