Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (10): 100602-100602.doi: 10.11889/j.0253-3219.2020.hjs.43.100602

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Study on thorium utilization and conversion in 2 MW liquid molten salt reactor

Peng CHEN1,2,Bo ZHOU1,Rui YAN1(),Yang ZOU1()   

  1. 1.Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-01-20 Revised:2020-04-20 Online:2020-10-15 Published:2020-10-14
  • Contact: Rui YAN,Yang ZOU;
  • About author:CHEN Peng, male, born in 1992, graduated from Hubei University in 2015, master student, focusing on the field of reactor physics
  • Supported by:
    Strategic Priority Research Program of Chinese Academy of Sciences(XDA02010000);Thorium Uranium Fuel Cycle Characteristics and Key Problem Research Project(QYZDY-SSW-JSC016);Shanghai Natural Science Foundation(19ZR1468000)

Abstract: Background

Thorium-uranium fuel cycle has the advantages of making use of abundant thorium resources, producing less nuclear waste and low toxicity, as well as nuclear non-proliferation. Molten salt reactor is an ideal type of nuclear energy utilization of thorium resources. The amount of thorium added in the core fuel can affect the thorium-uranium conversion performance in the molten salt reactor.


This study aims to understand the effect of thorium addition on the conversion performance of thorium and uranium in molten salt reactor.


Based on MCNP (Monte Carlo N Particle Transport Code) program, the core physical model was established. The neutron physical characteristics and thorium-uranium conversion characteristics of 2 MW (thermal power) liquid fuel experimental reactor under different thorium additions running at full power for 300 days were analyzed by using MOBAT (burnup code coupled with MCNP and ORIGEN2 using BATch language) burnup program. Analysis objectives included the energy spectrum changes at the beginning and the end of burnup, Xe equilibrium, as well as the consumption ratio and transfer characteristics, and the evolution of important nuclides in thorium uranium chain.


The results show that the consumption rate of thorium decreases with the increase of added amount. CR raises with the increase of Thorium addition, but the growth rate decrease gradually. The rate at which 233Th concentration reaches the maximum value is linearly related to the thorium mass, and the 233Pa has the same evolution trend as the 233Th. The higher the thorium content in the fuel, the higher the concentration of 233U, and the accumulation of 233U increases with the running time. Based on the radiochemical detection limit, 80 kg thorium can meet the minimum detection value after 4 days.


Based on the data of thorium-uranium conversion, the amount of uranium fuel needed to maintain the back-up reactivity, the limit of radiochemical detection and other factors, the experimental reactor can carry out the utilization of thorium in the order of tens to hundreds of kilograms and the verification experiment of Thorium-Uranium cycle, with the priority of about 80 kg. In addition, the more thorium was added, the more Uranium needed to be added. The increase of 135I concentration will increase the equilibrium concentration of Xe. The more thorium is added, the harder the neutron spectrum and the higher the 233U output will be, which means that it is easier to achieve transformation or proliferation under the fast neutron spectrum.

Key words: Consumption rate, Thorium-uranium chain, Thorium-uranium conversion, Neutron energy spectrum, Proliferation

CLC Number: 

  • TL27