Thermal Stratification Study for Pressurizer Surge Line

In order to confirm the structural integrity of pressurizer surge line affected by thermal strati-fication,this paper theoretically analyzes the criterion of thermal stratified occurrence,establishes the thermal stratified transient by start-up of reactor,and studies the calculation method of thermal stratified stress.A complex 3-dimension problem is simplified into a combined one of 1-dimension and 2-dimension.Consider-ing ANSYS code function,an engineering method is put forward for thermal stratified stress calculation of pressurizer surge line.