Recent developments in explicit finite element techniques and their application to reactor structures

A triangular element which requires only one quadrature point per element is described along with its implementation in the nonlinear, explicit time integration program SAFE/RAS. The implementation of an Ilyushin flow law which eliminates the need for integration through the thickness and simple formulas for stable time steps is also described. The performance of the triangular and quadrilateral elements is compared in large deflection, elastic-plastic problems. Applications to the analysis of above-core structures in breeder reactors are also described.