氟盐冷却高温堆氚输运特性瞬态分析

摘要

Tritium,as an inherent detrimental byproduct of molten salt reactor (MSR),featured with corrosivity and permeability,is one of the most critical problems confining the development of MSR.In this paper,tritium transport characteristics for fluoridesalt-cooled high-temperature reactor (FHR) were analyzed including tritium production rate,graphite absorption,and tritium dissolution in molten salt,corrosion and deposition reactions as well as T2 diffusion,under transients such as unprotected reactivity insertion (URI) accident and unprotected overcooling (UOC) accident.It is found that tritium transport characteristics become much more complicated under transient conditions than steady state,and they are strongly coupled with each other,bringing higher requirements for the performances of the tritium control equipment.Furthermore,the rates of T2 diffusing to the secondary loop both decrease under URI accident and UOC accident,averting the operation of extra safety facilities for tritium control.%氚是熔盐堆运行过程中的固有产物,具有强腐蚀性和渗透性,是限制熔盐堆技术发展的瓶颈问题之一.本文围绕氟盐冷却高温堆(FHR)中氚输运特性在事故工况下的瞬态响应开展研究,主要讨论在无保护反应性引入(URI)及无保护冷却剂入口过冷(UOC)事故下,熔盐堆一回路中的氚产率、石墨吸附量、熔盐溶解量、腐蚀与沉积反应以及氚向二回路的扩散等特性.研究发现,瞬态条件下氚输运特性较稳态时更为复杂多变,呈现出强烈的动态耦合特点,这对氚控设备的性能提出了更高的要求.计算表明,在URI和UOC事故下,氚向二回路的扩散速率均降低,不需投入额外的氚控安全设施.