摘要
10-MWt固态钍基熔盐堆(Thorium-based Molten Salt Reactor-Solid Fuel,TMSR-SF)使用TRISO(Tri-structural isotropic)颗粒燃料元件,并采用熔融氟盐作为一回路冷却剂,附着在燃料元件上的熔盐有可能影响系统反应性。因此,需要分析在燃料元件的贮存过程中熔盐附着燃料元件对贮存临界安全的影响。使用SCALE6.1的TRITON(Transport Rigor Implemented with Time-dependent Operation for Neutronic depletion)模块对TMSR-SF堆芯建模并进行燃耗计算,使用MCNP对乏燃料贮存系统进行临界计算。分别考虑熔盐浸渗球形燃料元件和熔盐包覆在球形燃料元件表面两种典型情况下,熔盐附着对贮存系统反应性的影响。针对乏燃料贮存系统,以浸渗最大量,即熔盐体积是石墨体积的13.9%为前提,临界计算结果表明,熔盐浸渗入石墨基体贮存系统的反应性比熔盐包覆在球形燃料元件表面的贮存系统的反应性要大5%;与没有熔盐附着的情况相比,有熔盐附着的情况下贮存系统反应性要大15%。对乏燃料贮存系统的临界安全分析可知,两种典型的熔盐附着模型对贮存系统的反应性存在一定的影响,但无论是熔盐浸渗还是包覆,贮存系统仍处于次临界,意味着贮存系统在正常工况下是安全的。
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 bum-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.
出处
《核技术》
CAS
CSCD
北大核心
2015年第5期86-91,共6页
Nuclear Techniques
基金
中国科学院战略性先导科技专项(No.XDA02005002)资助
关键词
钍基熔盐堆
乏燃料元件
熔盐浸渗
临界计算
临界安全分析
TMSR
Spent nuclear fuel element
Molten salt infiltrate
Criticality calculation
Criticality safetyanalysis
