We apply the Implicitly Restarted Arnoldi Method (IRAM), a Krylov subspace iterative method, to the calculation of k-eigenvalues for nuclear criticality problems. We show that the method can be implemented with only modest changes to existing power iteration schemes in a transport code. Numerical results on three dimensional unstructured tetrahedral meshes are shown.

This is a joint work with Jim Warsa of Los Alamos National Lab.