CPR1000核电厂未能紧急停堆的预期瞬态保护信号及缓解系统改进

摘要

CPR1000核电厂发生丧失正常给水‐未能紧急停堆的预期瞬态（LOFW‐ATWS）时，若温度调节（R ）棒组和功率调节（G ）棒组的调节功能不能及时作用或丧失，存在一回路超压的风险。为降低瞬态过程中的一回路压力峰值，避免超压的风险，本文提出了瞬态过程中增设反应堆冷却剂泵停运的保护信号及缓解系统改进方案，并采用T H EM IS程序进行改进方案的验证分析。结果表明，该改进方案可有效降低LOFW‐ATWS事故下一回路压力峰值，消除一回路超压的风险。%At the event of loss of normal feedwater‐anticipated transient without scram (LOFW‐ATWS) in CPR1000 nuclear power plant ,the primary loop overpressure risk may exist when the regulation functions of temperature regulation (R) rods and power regulation (G) rods cannot work timely or have lost .In order to reduce the peak value of primary pressure and avoid the overpressure risk in this transient process , an improvement scheme of ATWS protective signal and mitigation system by adding shut‐down action of coolant pumps was proposed in this paper ,and then THEMIS program was adopted to verify this scheme .The verification results indicate that the improve‐ment scheme can effectively reduce the peak value of primary pressure and eliminate overpressure risk in LOFW‐A T WS event .