摇摆条件下海上浮动堆全厂断电事故分析

Analysis of SBO Accident in Floating Nuclear Reactor under Rolling Condition

为研究海洋条件对海上浮动堆全厂断电事故后的事故进程及非能动安全系统运行特性的影响,通过建立海洋条件加速度场模型,基于RELAP5程序开发获得了适用于海上浮动堆的系统分析程序,并对程序进行了实验验证。利用所开发的程序通过建立双环路海上浮动堆及二次侧非能动余热排出系统的计算模型,开展了不同摇摆运动参数下海上浮动堆全厂断电事故的计算分析。计算结果表明,船体的横摇运动可加快全厂断电事故后浮动堆系统压力和温度的下降速度,堆芯余热能够被二次侧非能动余热排出系统有效导出;但横摇运动会造成事故后堆芯自然循环流量的显著降低,引起一回路系统和非能动余热排出系统中自然循环流量的大幅度振荡及周期性倒流。本文计算结果可为海上浮动堆非能动安全系统的设计提供参考。

To study the effect of ocean conditions on the station blackout （SBO） accident process for floating nuclear reactor and the response characteristic of passive safety system, a modified RELAP5 code which considered ocean conditions was developed and validated by experiment. A calculation model of two-looped floating nuclear reactor with the secondary passive residual heat removal system （PRHRS） was established. The numerical analysis of SBO accident in floating nuclear reactor under different rolling con- ditions was conducted by the modified code. The results show that rolling motion accel- erates the decreasing rate of system pressure and temperature. The core decay heat can,be effectively removed by the secondary PRHRS. But ship rolling motion can cause the marked descent of the natural circulation flow rate in the core during SBO accident process. The natural circulation flow rate of the primary loop and PRHRS oscillates with rolling motion and periodic reversal flow appears. The results can provide technical support for the design of passive safety system of floating nuclear reactor.