核电站温排水融冰特性的数值模拟

Study on ice melting by thermal drainage of nuclear power plants based onnumerical simulation

北方核电厂建设项目环境影响评价环节中,不考虑结冰条件会导致取水温升的选取偏保守,从而造成经济损失。为了探讨寒区海域核电站温排水的温升及融冰特性,采用三维潮流场和温排水模型,考虑大气-海冰界面热流通、海冰内部热传导、海冰-海洋界面热流通与海冰生消的热力学过程,以徐大堡核电厂为例研究了温排水在结冰条件下的扩散规律和融冰范围。结果表明,大潮表层温升为0.5℃、1.0℃和2℃考虑结冰影响的最大温升包络面积较无冰时分别减少了38.93%、32.18%和3.72%;且1~6号机组同时运行时的温排水融冰范围较1~4号机组同时运行时偏大36.31%。此外,暗管排水方式占主导的工况与明渠排水方式占主导的工况相反,由于排水源更靠近底层,因此表层、中层和底层最大温升包络面积依次增大。该项研究可为寒区海域核电站的环境影响评价提供一种新方法。

In the environmental impact assessment process of northern nuclear power plant construction projects,the influence of icing conditions on the water temperature rise is not considered in the numerical simulation analysis of thermal discharge,which leads to the conservative and uneconomical selection of water temperature rise.To explore the temperature rise and ice melting characteristics of thermal drainage from nuclear power plants in cold regions,a three-dimensional tidal current field and thermal drainage model are established including the thermodynamic process of air-sea ice interface heat flow,sea ice internal heat conduction,sea ice-ocean interface heat flow,and sea ice generation and dissipation.Taking Xudapu Nuclear Power Plant as an example,the diffusion law and melting range of thermal drainage with ice effects are studied.The results show that the maximum temperature rise envelope area affected by sea ice with a surface temperature rise of 0.5℃,1.0℃,and 2℃during the spring tide is reduced by 38.93%,32.18%,and 3.72%;respectively,compared to those without sea ice effects;And the melting range caused by the temperature drainage during the simultaneous operation of Units 1-6 is 36.31% larger than that during the simultaneousoperation of Units 1-4. In addition, the working conditions dominated by concealed pipe drainage are oppositeto those dominated by open channel drainage. As the drainage source is closer to the bottom layer, themaximum temperature rise envelope area of the surface, middle, and bottom layers increases sequentially. Thisstudy can provide a new method for environmental impact assessment of nuclear power plants in cold regions.