西安脉冲堆反应性引入事故瞬态安全特性分析

为研究西安脉冲堆（XAPR）在意外引入反应性且停堆系统失效事故下的瞬态安全特性，本文基于XAPR的结构和运行特点，建立了适用于XAPR的瞬态热工水力分析模型，并开发了用于XAPR安全特性分析的瞬态热工水力程序TSAC-XAPR。利用TSAC-XAPR程序对反应性引入事故进行模拟计算，结果表明：当XAPR在额定功率范围内运行时，发生反应性引入事故后，堆芯能依靠自身的固有反馈机制使脉冲堆重新达到稳定运行状态；当运行功率过高尤其是超过临界值时，反应性引入事故将导致脉冲堆关键热工水力参数发生振荡，无法再次达到稳态。此外，不同反应性引入方式将影响堆芯参数在反应性引入过程中的变化趋势，但并不影响其最终稳态值。

Transient Safety Characteristic Analysis of Xi’an Pulsed Reactor during Reactivity Insertion Accident

In order to study the transient safety characteristics of Xi’an Pulsed Reactor (XAPR) when unexpected reactivity insertion accident happened and shutdown system failed, the main mathematical models were established based on the specific core structure and operation conditions of XAPR. Meanwhile, a transient thermal-hydraulic code called TSAC-XAPR was developed to analyze the safety characteristics of XAPR. The TSAC-XAPR code was then used to simulate the reactivity insertion accident of XAPR. The calculation results indicate that when XAPR operating under rated power, reactor can reach a new steady state for reactivity insertion accident, depending on its inherent feedback mechanism. When XAPR operating under high power, especially above the critical power, key thermal-hydraulic parameters of reactor will tend to oscillate and can’t reach a steady state again for reactivity insertion accident. Besides, it is also found that different reactivity insertion modes will only affect the variation trend during the phase of reactivity insertion instead of the final value at steady state.