Study on Response and Consequence of Loss of Coolant Accident in Integrated Small Reactor
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摘要: 为全面分析一体化小型模块式反应堆(简称小堆)失水事故,基于RELAP5程序建立了包括堆芯、主回路和安全壳在内的整体分析模型,对堆芯和安全壳瞬态响应及环境放射性后果进行计算分析,结果表明事故后果满足小堆安全审评原则规定的验收准则。此外,提出了改进的紧贴式安全壳方案及可选的参数配置,计算结果表明采用改进方案可使一回路和安全壳压力很快达到平衡,更早终止破口流量,从而减少一回路失水量和放射性释放量,提升堆芯安全性并降低事故剂量后果,壳外水池容量可保障安全壳长期冷却。研究成果可为一体化小堆工程应用和安全壳设计提供参考依据。
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关键词:
- 一体化小型模块式反应堆(简称小堆) /
- 失水事故 /
- 瞬态响应 /
- 放射性后果 /
- 紧贴式安全壳
Abstract: The overall analytic model including the core, primary loop and containment was established base on RELAP5 code to fully analyze the Loss of Coolant Accident (LOCA) for the integrated small modular reactor (or small reactor for short). The transient response of the core and containment as well as the radiological consequence for the environment were calculated and analyzed. The results showed that the accident consequences met the acceptance criteria stipulated in the small reactor safety review principle. Besides, the improved scheme of close-fitting containment and the optional parameter configuration were proposed. The calculation results show that with the improved scheme, the pressure balance of the primary loop and containment can be achieved very shortly and the break flow is terminated earlier, so the loss of primary coolant and the radiological release are reduced. The core safety is enhanced, and the dose consequence of the accident is decreased. Meanwhile, the long-term cooling of containment can be ensured by the pool outside the containment. The research results can provide references for the engineering application and containment design of the integrated small reactor. -
表 1 反应堆及安全壳初始参数
Table 1. Initial Parameters of the Reactor and Containment
参数 数值 堆芯功率/MW 210 一回路压力/MPa 8.08 堆芯出口温度/℃ 279.5 堆芯入口温度/℃ 233.5 RPV水位高度/m 11.518 堆芯旁流份额/% 5 安全壳压力/MPa 0.101 安全壳温度/℃ 45 安全壳自由容积/m3 16590 表 2 瞬态事件序列
Table 2. Transient Event Sequences
瞬态事件 时间/s 瞬态开始 0.0 触发停堆信号 31.9 控制棒开始下落 33.9 中间回路开始隔离 33.9 一回路和安全壳开始隔离 33.9 RHR出口隔离阀开启 51.9 安全壳压力达到峰值 1622 一回路与安全壳压力达到平衡 约14840 表 3 安全壳及反应堆水池参数
Table 3. Parameters of Containment and Reactor Pool
参数 数值 配置1 配置2 配置3 配置4 配置5 安全壳内径/m 5.2 5.2 5.2 5.6 6.0 安全壳壁厚/m 0.3 0.2 0.12 0.3 0.3 安全壳自由容积/m3 58.8 58.8 58.8 109.7 164.4 安全壳高度/m 15 安全壳运行压力/MPa 0.001 安全壳运行温度/℃ 45 反应堆水池水位高度/m 8 反应堆水池水体积/m3 693 反应堆水池运行压力/MPa 0.101 反应堆水池运行温度/℃ 45 表 4 改进方案LOCA计算结果
Table 4. LOCA Calculation Results under the Improved Scheme
参数 数值 配置1 配置2 配置3 配置4 配置5 一回路与安全壳压力达平衡时间/s 约1298 约1292 约1294 约1514 约1994 安全壳峰值压力/MPa 3.519 3.520 3.521 3.013 2.616 安全壳压力达峰值时间/s 485 485 485 520 652 RPV剩余水位标高/m 6.61 6.62 6.71 6.53 6.42 一回路失水量/t 39.0 38.8 38.3 39.4 40.6 反应堆水池温度/℃ 45.2 45.5 45.9 45.2 45.2 -
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