The Analytic Nodal Method for CANDU Reactor Three-Dimensional Space-Time Kinetics Calculations

Abstract

The Analytic Nodal Method (ANM) is noted as an accurate and efficient numerical method for solving the multidimensional, two-group kinetics neutron-diffusion equation. The only approximation introduced during the derivation of ANM is the shape of the transverse leakage. The spatial coupling is determined by the analytic solution of one-dimensional diffusion equations. The resulting super-matrix equations can be written in terms of node-averaged fluxes and face-averaged net leakages, and have the form of a classical eigenvalue problem which can be solved by the standard source iteration procedure. The Analytic Nodal Method has been implemented in the code NDF, and tested for two CANDU problems. The calculations clearly indicate that the ANM is more accurate than the Coarse Mesh Finite Difference (CMFD) method for CANDU analysis.