EQUICORE II: a two dimensional coupled hydraulic-neutronics code for calculating the equilibrium and time dependent burnup states of pressure tube type reactors.

Abstract

The Equicore II code calculates the burnup, power distribution and coolant conditions of pressure tube type reactors for both the equilibrium and time dependent core conditions. The code has been designed to be both easy to use and economic in computing time. To achieve this, the overall core burnup and hydraulic performance is obtained by considering only a few representative fuel assemblies and by using flux distributions derived from an RZ-diffusion calculation, based on volume elements containing the average properties of these representative fuel assemblies. A separate RZ supercell calculation model is available to determine the detailed flux and power variation between selected fuel assemblies and the average properties within radial zones of the core. The code also incorporates a user-oriented facility which allows, at any stage of the burnup calculation, the determination of such things as space dependent temperature coefficients and time dependent variation of xenon concentration. This report describes the models used in the code and gives the data requirements.