Application of Monte Carlo method to calculate the effective delayed neutron fraction in molten salt reactor

  • Gui-Feng Zhu
  • Rui YanEmail author
  • Hong-Hua Peng
  • Rui-Min Ji
  • Shi-He Yu
  • Ya-Fen Liu
  • Jian Tian
  • Bo Xu


Delayed neutron loss is an important parameter in the safety analysis of molten salt reactors. In this study, to obtain the effective delayed neutron fraction under flow condition, a delayed neutron precursor transport was implemented in the Monte Carlo code MCNP. The molten-salt reactor experiment (MSRE) model was used to analyze the reliability of this method. The obtained flow losses of reactivity for 235U and 233U fuels in the MSRE are 223 pcm and 100.8 pcm, respectively, which are in good agreement with the experimental values (212 pcm and 100.5 pcm, respectively). Then, six groups of effective delayed neutron fractions in a small molten salt reactor were calculated under different mass flow rates. The flow loss of reactivity at full power operation is approximately 105.6 pcm, which is significantly lower than that of the MSRE due to the longer residence time inside the active core. The sensitivity of the reactivity loss to other factors, such as the residence time inside or outside the core and flow distribution, was evaluated as well. As a conclusion, the sensitivity of the reactivity loss to the residence time inside the core is greater than to other parameters.


Monte Carlo Effective delayed neutron fraction Molten salt reactor 


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Copyright information

© China Science Publishing & Media Ltd. (Science Press), Shanghai Institute of Applied Physics, the Chinese Academy of Sciences, Chinese Nuclear Society and Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Gui-Feng Zhu
    • 1
  • Rui Yan
    • 1
    Email author
  • Hong-Hua Peng
    • 1
  • Rui-Min Ji
    • 1
  • Shi-He Yu
    • 1
  • Ya-Fen Liu
    • 1
  • Jian Tian
    • 1
  • Bo Xu
    • 1
  1. 1.Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghaiChina

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