Analysis of Mitigation Effect of Passive Pulse Cooling System on SBO/TLFW Accident in PWR
-
摘要: 针对二代堆核电厂目前的事故规程难以处理全厂失电(SBO)与完全丧失给水(TLFW)事故叠加的情况(SBO/TLFW),非能动脉冲冷却是一种充分利用二代堆核电厂二回路现有设备系统以延缓事故进程的新思路。为分析非能动脉冲冷却系统对SBO/TLFW事故的缓解作用,基于最佳估算系统程序RELAP5建立了中国改进型三环路压水堆(CPR1000)机组主系统、二回路和非能动脉冲冷却系统模型,在此基础上开展了SBO/TLFW事故工况分析,对比了有、无非能动脉冲冷却系统情况下的事故进程。计算结果表明,在停堆后8 min内开始启动且仅依靠除氧器存水,非能动脉冲冷却系统能够将堆芯开始裸露的时间推迟约12 h,可以显著延缓压水堆的SBO/TLFW事故进程。
-
关键词:
- 非能动脉冲冷却 /
- 全厂失电(SBO) /
- 完全丧失给水(TLFW)
Abstract: The current accident regulations of the second-generation reactor nuclear power plant are not enough to handle the superposition accident (SBO/TLFW) of the Station-Black-Out (SBO) and the Total Loss of Feed-Water (TLFW) accidents. Passive pulse cooling is a new approach to delay the accident process by fully utilizing the existing equipment and system in the secondary circuit of the second-generation reactor nuclear power plant. In order to analyze the mitigating effect of the passive pulse cooling system on SBO/TLFW, based on the best-estimate system code RELAP5, models of the primary system, the secondary circuit and the passive pulse cooling system of the CPR1000 unit were established, and accident scenarios were analyzed for the SBO/TLFW accident. The accident processes with and without the passive pulse cooling system were compared. The calculation results show that if the passive pulse cooling system is started within eight minutes following reactor scram, the core uncovering can be delayed by 12 hours, merely relying on the water stored in the deaerator, which can significantly delay the SBO/TLFW accident process in PWR. -
表 1 主要系统参数设计值与RELAP5稳态计算结果对比
Table 1. Comparison between Design Values of Main System Parameters and RELAP5 Steady-state Calculations
参数 设计值 RELAP5计算值 稳压器压力/MPa 15.5 15.49 稳压器水位/% 62.70 62.47 压力容器进口温度/℃ 292.4 293.6 压力容器出口温度/℃ 327.6 327.4 主系统单环路流量/(m3·h−1) 23790 23790.88 蒸发器二次侧窄量程水位/% 50 50 蒸发器二次侧压力/MPa 6.89 6.89 蒸发器二次侧蒸汽流量/(kg·s−1) 538.3 540.6 表 2 SBO/TLFW事故序列
Table 2. SBO/TLFW Accident Sequence
事件 投入非能动脉冲冷却系统所需时间 未投入非能动脉冲冷却系统所需时间 给水丧失,全厂断电 0 s 0 s 给水流量低触发停堆信号 5 s 5 s 冷却蒸发器GCTa阀门全开卸压 485 s N/A 冷却蒸发器二次侧首次干涸 1160 s 4710 s(1.308 h) 除氧器开始给水 1220 s N/A 除氧器排空 25790 s(7.164 h) N/A 主系统开始达到饱和 34300 s(9.528 h) 5850 s(1.625 h) 动力蒸发器二次侧干涸 42700 s(11.861 h) N/A 堆芯开始裸露 46250 s(12.847 h) 5900 s(1.639 h) 堆芯出口温度达到650℃ 50610 s(14.058 h) 7950 s(2.208 h) 堆芯完全裸露 54090 s(15.025 h) 9590 s(2.664 h) N/A表示不适用 -
[1] 周景月,张培栋,徐艳,等. "后福岛时代"中国核电发展现状与趋势[J]. 未来与发展,2015(9): 42-46. [2] MARGUET S. A brief history of nuclear reactor accidents: from Leipzig to Fukushima[M]. Cham: Springer, 2022: 29-380. [3] 环境保护部核与辐射安全监管二司,环境保护部核与辐射安全中心. 日本福岛核事故[M]. 北京: 中国原子能出版社,2014: 80-101. [4] 孔凡何,阮阳. 核电厂SBO应急柴油发电机组方案设计与应用[J]. 电气应用,2016, 35(2): 78-80. [5] 骆邦其,林继铭. CPR1000核电站严重事故重要缓解措施与严重事故序列[J]. 核动力工程,2010, 31(S1): 1-3, 7. [6] PASSALACQUA R. Direct containment heating: a solved risk issue[C]//Proceedings of the 10th International Conference on Nuclear Engineering. Arlington: ASME, 2002: 51-59. [7] 吴震华,许俊俊,孙开宝,等. 核电厂非能动脉冲冷却方法以及系统: 中国,202010159518.5[P]. 2022-07-29. [8] WU Z H, XU J J, WANG W J, et al. Study on passive pulse cooling method of secondary side in PWR nuclear power plant[C]//Proceedings of the 29th International Conference on Nuclear Engineering. Virtual: ASME, 2022: V011T11A020. [9] 石建中,薛海青,胡友情. 1000MW级核电厂大型除氧器选型分析[C]//科技创新促进中国能源可持续发展“首届中国工程院/国家能源局能源论坛论文集”. 北京: 化学工业出版社,2010: 503-507. [10] FLETCHER C D, SCHULTZ R R. RELAP5/MOD3 code manual: NUREG/CR-5535-Vol. 5[R]. Idaho Falls: Idaho National Engineering Lab., 1992.