Simple functional method for calculating axial power distribution of PWR core.

Abstract

A new, far simpler, method is presented to replace the laborious one-dimensional diffusion code calculations currently practised for deriving the axial power distribution through reactor core—an important factor in determining the hot channel factor of PWR cores. With the new method, the axial power distribution is approximated by a combination of simple functions, using as intermediate parameter the “axial offset”, representing the extent of imbalance in aggregate power output between the upper and lower core halves. The new simplified method reduces almost to 1/50 the computer time required for deriving the axial power distribution for any given condition of reactor operation, compared with that demanded by 1-D diffusion code calculations, with deviation of resulting values at peak power position hardly exceeding 2%. The proposed method promises to serve usefully for plant-side calculations and analytical treatment of the axial power distribution.