3次元FEM解析による円筒容器に取り付けられた管台の応力分類における板厚の影響検討

抄録

In current practices, stress analyses of Class 1 vessels with internal pressure of nuclear power plants have been carried out using the minimum thickness of the component. In this paper, effects of thickness on stresses have been investigated by comparing stress analysis results for two kinds of 3D-FEA models of a typical nozzle attached to a cylindrical vessel with minimum thickness and nominal thickness. Since variations of stresses between minimum and nominal thickness models are small, nominal thickness can be employed in the 3D-FE analysis. However, in case of evaluations for primary stresses, a correction method to multiply primary membrane stress by the thickness ratio and primary bending stress by the thickness ratio squared should be used in order to conduct conservative evaluation.