Analysis of Post-Accident Debris Transport Performance in In-Containment Refueling Water Storage Tank in Nuclear Power Plants
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摘要: 为避免事故后安全壳内置换料水箱（IRWST）内滤网堵塞，保证IRWST下游泵的安全运行，需对IRWST内碎片传输效果进行精细评估。针对某核电厂双环池型IRWST，采用计算流体动力学（CFD）方法对其流场进行了模拟，通过高速区和高湍动能区体积比定量评价事故后碎片传输效果。结果表明，事故后各工况下IRWST内碎片传输比均未超过滤网的设计值，保证了事故后滤网及相连系统的安全性；只有内环滤网A投运时，滤网的负载最大；影响事故后碎片传输效果的主要因素是流场的高速区。针对IRWST的现有布置空间，提出了增大外环搅混管线管径的优化方案，可以显著降低事故后IRWST内碎片传输比，提升事故后核电厂的安全性。
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关键词:
- 安全壳内置换料水箱（IRWST） /
- 碎片传输 /
- 计算流体动力学（CFD）
Abstract: To avoid the blockage of strainer in the in-containment refueling water storage tank (IRWST) and guarantee the safe operation of the pump downstream the IRWST after accident occurrence, the debris transport performance in the IRWST must be evaluated carefully. For the double-loop pool-type IRWST of a nuclear power plant (NPP), the Computational Fluid Dynamics (CFD) method is adopted to simulate the flow field of this IRWST, and the volume ratio of the high velocity region and high turbulent kinetic region is used to quantitatively evaluate the debris transport performance of the IRWST. The results indicate that the debris transport ratio of IRWST does not exceed the design value of the strainer under various post-accident conditions, which ensure the safety of the strainer and its connected systems after accident occurrence; the strainer load reaches the maximum value when only the strainer A in the inner loop is put into operation; and the post-accident debris transport performance is mainly affected by the high velocity region in the flow field. As a result, this paper proposes the optimization scheme, namely, increasing the diameter of the mixing pipeline in the outer loop, for the existing IRWST layout. This scheme can reduce greatly the debris transport ratio in the IRWST after accident occurrence and thus improve the post-accident safety of the NPP. -
图 1 某核电厂双环池型IRWST简化模型图
Figure 1. Simplified Model of Double-Loop Pool-Type IRWST in a NPP
图 2 工况1下IRWST高速区和高湍动能区分布
Figure 2. Distribution of High Velocity Region and High Turbulent Kinetic Region in IRWST under Condition 1
图 3 工况1下IRWST中平面速度矢量图
Figure 3. Velocity Vector on Mid-Plane of IRWST under Condition 1
图 4 工况2下IRWST中平面速度矢量图
Figure 4. Velocity Vector on Mid-Plane of IRWST under Condition 2
图 5 工况3下IRWST中平面速度矢量图
Figure 5. Velocity Vector on Mid-Plane of IRWST under Condition 3
表 1 不同工况下IRWST入口无量纲流量
Table 1. Dimensionless Flow at IRWST Inlet under Different Conditions
工况编号 单个内环滞留篮 单个外环滞留篮 单个外环搅浑管线 工况 1 1.95 1.69 2.93 工况 2 1.95 1.69 2.93 工况 3 3.90 3.38 5.87 工况 4 3.90 3.38 5.87 工况 5 1.15 1 0 
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表 2 不同工况碎片传输效果对比 %
Table 2. Comparison of Debris Transport Performance under Different Conditions
工况
编号高速区
体积比高湍动能
体积比高速或高湍动能
叠加区域体积比单个滤
网负载工况 1 45.8 3.0 46.0 46.0 工况 2 32.8 3.5 33.1 33.1 工况 3 33.3 4.7 33.5 16.8 工况 4 57.6 6.3 58.2 29.1 工况 5 0 0 0 0
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表 3 2种方案下不同工况的高速或高湍动能区域叠加体积比 %
Table 3. Comparison of Accumulated Volume Ratios of High Velocity Region or High Turbulent Kinetic Region between the Two Schemes
工况编号 原始方案-DN100 优化方案-DN150 降低幅度 工况1 46.0 36.0 21.7 工况2 33.1 23.4 29.3 工况3 33.5 21.7 35.2 工况4 58.2 39.1 32.8
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[1] 侯建飞,夏愈卓. 某核电厂安全壳内置换料水箱搅混性能优化分析[J]. 核动力工程,2018, 39(4): 137-140. [2] 谢洪虎,李石磊,张峰,等. 核电厂安全壳内置换料水箱过滤系统过滤性能及阻力特性研究[J]. 核动力工程,2019, 40(6): 130-134. [3] 葛增芳. 地坑内流场及碎片传输份额分析[D]. 哈尔滨: 哈尔滨工程大学, 2013. -
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