Finite Element Analysis of Some Critical Fast Assemblies

The finite element method is applied in multigroup formalism to the analysis of some fast and intermediate spherical critical systems. The approximation scheme is based on a self-adjoint variational principle associated with the formally self-adjoint form of the monoenergetic transport equation. A number of experimental critical assemblies are analyzed using unmodified and modified Hansen-Roach 16-group cross sections. Comparison of the results with those obtained by S_N calculations indicates that high accuracy is obtained by low-order finite element techniques. Several optional strategies are proposed which may further accelerate the convergence of finite element solutions.