Structural analysis of the gas-cooled fast breeder reactor core support

Abstract

The report presents the results of a comprehenaive study of the effect of pressure loading on the gas-cooled fast breeder reactor (GCFR) core support structure. Two theories are investigated for the core support grid plate: thin plate theory and anisotropic elasticity theory. The case of an isotropic thick plate is also presented. The effect of transverse shear and normal stress in a thick plate and the effect of the outer solid rim of the perforated interior portion of the grid plate are studied. The grid plate support structure upper flange, support cylinder, and lower flange are analyzed, and the structural interaction between the grid plate and the support structure is discussed. Numerical results are presented for each analyss. The stresses obtained in the grid plate and the support structure are evaluated according to the requirements of the ASME Boiler and Pressure Vessel Code, Section III, Division 1, and the deflections of the grid plate are examined to determine whether the reactivity insertion limitation on the plant safety requirements is met. Since the final dimensions of the core support structure are not certain at this time, the report is not considered to be a final design stress report; however, it does more » examine the feasibility of the design and also demonstrates the analytical methods used to solve the grid plate problem from the standpoint of pressure loading. « less