严重事故专用卸压阀排放能力需求

二代加百万千万级核电站严重事故下卸压过程中高温流体流经卸压阀，可能造成流道变形，甚至造成阀杆下落使得排放流道封闭，造成卸压失败。对严重事故专用卸压阀在卸压过程中可能经历的高温流体状态进行谱分析，获得了不同卸压能力下阀门经受的高温流体状态。开展了高温可能引起的阀门流道变形对卸压效果的影响分析。第二类阀门虽然存在阀门流道变形的可能，但能够获得较长严重事故处置时间，从优化严重事故对策的角度，严重事故专用卸压阀推荐采用第二类阀门排放能力450～600 t/h范围。

Discharge capacity requirements of severe accident depressurization valves

In the process of depressurization during severe accidents for the second generation nuclear power plant, high temperature fluid flowing through the severe accident depressurization valves may cause deformation of the valve body or even cause the valve stem to fall down because of being heated by high temperature fluid, resulting in depressurization failure. In this paper, the spectrum analysis of the high temperature fluid state that the depressurization valve may experience in the process of pressure relief is carried out, and the high temperature fluid state under different pressure relief capacities is obtained. The influence of the valve channel deformation caused by high temperature on the depressurization effect is studied. Although the second type valve has the possibility of valve channel deformation, it can obtain a longer time window for severe accident mitigation. From the perspective of optimizing the severe accident measures, the discharge capacity range of the second type valve 450-600 t/h is recommended.