熔盐堆核燃料盐贮存的核临界安全分析

Criticality safety analysis of nuclear fuel storage of molten salt reactor

熔盐堆是国际公认推荐的6种第四代反应堆型之一,可以使用液态核燃料,其核燃料生产、转运和贮存所涉及工艺过程与常规固态核燃料堆型也不同。为做好核燃料管理和核安全监管,有必要对其贮存的临界安全进行分析。本研究参考美国液态燃料熔盐反应堆MSRE(Molten Salt Reactor Experiment)相关设计参数,通过选取液态燃料熔盐堆核燃料的贮存建模、临界参数分析、蒙特卡罗中子输运软件仿真模拟计算,分析不同因素对核燃料盐贮存的影响,总结了设计模型下干燥环境贮存、水淹环境贮存的keff值及与燃料盐总质量变化的规律。最终,得到了不同情况下次临界安全控制的质量及与对应原料盐、中间产物、考虑容器壁影响时的对比。本研究结合法律法规及核材料流转过程进行分析讨论,归纳核燃料盐核临界安全特性,从核安全监管角度首次提出了相关监督审评要点。

[Background]Molten salt reactor is one of the six internationally recognized and recommended fourth generation reactors that can use liquid nuclear fuel.The production,transportation,and storage of nuclear fuel involve different processes from conventional solid-state nuclear fuel reactors.[Purpose]This study aims to perform criticality safety analysis for nuclear fuel storage of molten salt reactor in compliant with requirements of nuclear fuel management and nuclear safety supervision.[Methods]The design parameters of MSRE(Molten Salt Reactor Experiment)were referred for criticality safety analysis,and the impact of different factors on nuclear fuel salt storage was analyzed.Calculation was completed by selecting storage modeling,critical parameter analysis,and Monte Carlo neutron transport software simulation for liquid fuel molten salt reactor nuclear fuel.The k_(eff) values of dry environment storage and water flooded environment storage under the design model were summarized, so did thechanges in the total mass of fuel salt. [Results & Conclusions] The quality of subcritical safety control underdifferent conditions are obtained and compared with corresponding raw material salts, intermediate products, andconsideration of container walls. This study combines legal regulations and the process of nuclear material circulationfor analysis and discussion, summarizes the critical safety characteristics of nuclear fuel salt, and for the first timeproposes relevant supervision and evaluation points from the perspective of nuclear safety supervision.