超临界二氧化碳模块化微型堆瞬态安全分析

超临界二氧化碳反应堆是一种极具潜力的新堆型，目前正处于概念设计阶段。本文以韩国科学技术院（KAIST）设计的超临界二氧化碳模块化微型堆（MMR）为研究对象，对一回路系统主要部件进行建模，并利用FORTRAN语言开发了适用于超临界二氧化碳反应堆的瞬态安全分析程序TRA_SCR。基于该程序，对KAIST MMR进行了稳态计算分析，验证了程序的正确性。同时，对部分无保护失流事故和无保护反应性引入事故进行了瞬态计算，获得了关键热工水力参数的瞬态特性。计算结果表明该反应堆系统具有较强的固有负反馈特性，且在所计算的事故中，包壳、燃料和冷却剂温度均未超出安全限值，表明了系统在上述事故下的安全性。但在上述无保护失流事故中，堆芯冷却剂出口温度接近安全限值，表明在该事故工况下，反应堆出口温度是制约系统安全性能的关键因素。

Transient-state Safety Analysis of Supercritical CO2 cooled Micro-modular Reactor

Supercritical CO₂-cooled reactor, as a promising reactor, is at the conceptual design stage. The physical and mathematical models of the main parts of the primary circuit of supercritical CO₂-cooled micro-modular reactor (MMR) designed by Korea Advanced Institute of Science and Technology (KAIST) were established, and the transient and safety analysis code TRA_SCR for supercritical CO₂-cooled reactor was preliminarily developed with FORTRAN language. Steady state analysis shows the stability and dependability of TRA_SCR code for KAIST MMR. The variations of main parameters for loss of flow and reactivity insertion accidents without protection were calculated, and the transient safety characteristics of this system were preliminarily studied. The results show that KAIST MMR has strong inherent negative feedback characteristics, and under these two accidents, the temperatures of the cladding, fuel and coolant do not exceed the safety limitation. However, the outlet temperature of the core coolant is close to the safety limitation in loss of flow accident without protection, which shows that the outlet core temperature is the key factor limiting the safety performance of the system.