钠冷快堆熔断式非能动停堆系统方案设计

为保证和增强池式快堆的安全性，通过对比分析现有的非能动停堆装置，基于将某些合金在特定温度下拉伸强度发生突变的特性作为钠冷快堆非能动停堆的触发条件，提出了一种钠冷快堆熔断式非能动停堆系统的设计概念，能在发生无保护超功率事故或无保护失流事故的情况下引入负反应性。针对中国实验快堆(CEFR)的设计完成了熔断式非能动停堆系统的方案设计论证，并利用分析程序DYN4G对这一非能动停堆系统在CEFR无保护事故下的响应情况进行了模拟计算，由此得到了其组件设计的关键参数。分析结果表明，通过合理设计，在发生无保护事故时，熔断式非能动停堆系统能有效降低事故情况下的堆芯燃料组件及冷却剂的温度，进一步提高了钠冷快堆应对严重事故的能力。

Conceptual Design of Melting-alloy Passive Shutdown System for Sodium-cooled Fast Reactor

To ensure and enhance the safety of fast reactor, by comparing and analyzing the existing passive shutdown devices, a new design concept of the melting-alloy passive shutdown system for sodium-cooled fast reactor was proposed based on taking the sudden change of tensile strength of some alloys at certain temperature as the triggering condition for passive shutdown system. This system could bring negative reactivity to the core when unprotected transient-overpower accident or unprotected loss-of-flow accident occurred. A design scheme of melting-alloy passive shutdown system was completed based on China Experimental Fast Reactor (CEFR). The response of the passive shutdown system under the unprotected accident of CEFR was simulated by using DYN4G code and the key parameters of subassembly design for passive shutdown system were confirmed. The results show that during the unprotected accident, a melting alloy passive shutdown system can effectively reduce temperature of fuel subassembly and coolant, and improve the ability of sodium-cooled fast reactor to deal with severe accident.