Experimental Study on Steam Critical Flow Leakage from a Small Break in Pipeline of Pressurized Water Reactor
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摘要: 为探究压水堆核电厂小破口失水事故中管道小破口蒸汽临界流泄漏特性,开展了管道小破口泄漏实验,以探索饱和/过热蒸汽临界流泄漏特性。基于压力管道疲劳贯穿裂纹(微通道),开展了流体压力3~12 MPa、流体温度240℃~320℃范围内的蒸汽临界流泄漏实验。实验结果表明,蒸汽临界质量流速与初始流体压力呈正相关关系,与初始流体过热度呈负相关关系。与过冷水临界流泄漏相比,蒸汽临界质量流速受入口压力损失、摩擦效应与加速效应的影响相对较弱。利用一维等熵模型预测了蒸汽临界质量流速,预测值与实验值平均相对偏差为14.17%,表明一维等熵模型具有良好的蒸汽临界质量流速预测精度。Abstract: In order to explore the characteristics of steam critical flow leakage from a small break in pipeline during the loss of coolant accident of pressurized water reactor (PWR) nuclear power plant, small-break leakage experiments of pipelines are carried out in this paper to explore the characteristics of saturated/superheated steam critical flow leakage. Based on pressure pipeline fatigue through crack (microchannel), the steam critical flow leakage experiment is carried out within the fluid pressure range of 3~12 MPa and the fluid temperature range of 240℃~320℃. The experimental results show that the critical mass flow rate of steam is positively correlated with the initial fluid pressure and negatively correlated with the initial fluid superheat degree. Compared with the critical flow leakage of supercooled water, the critical mass flow rate of steam is less affected by inlet pressure loss, friction effect and acceleration effect. The one-dimensional isentropic model is used to predict the critical mass flow rate of steam. The mean relative deviation between the predicted value and the experimental value is 14.17%, which indicates that the one-dimensional isentropic model can accurately predict the critical mass flow rate of steam.
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Key words:
- Loss of coolant accident /
- Steam leakage /
- Two-phase critical flow /
- Fatigue crack
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表 1 实验件编号及尺寸
Table 1. Numbers and Dimensions of Test Pieces
参数 实验件尺寸 编号1 编号2 编号3 管道壁厚/mm 10 10 10 裂纹深度/mm 7.2 7.2 7.2 外壁面裂纹长度/mm 17.25 13.90 10.37 内壁面裂纹长度/mm 20 20 20 内壁面COD/mm 0.12 0.16 0.10 外壁面COD/mm 0.120 0.110 0.061 出口面积/mm2 2.07 1.53 0.63 表 2 关键参数不确定度
Table 2. Uncertainty of Key Parameters
参数 不确定度/% 温度 0.24~0.25 压力 0.74 流量 0.92 -
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