Numerical studies in the accuracy of conventional coarse mesh methods for PWR's

The application of conventional coarse mesh methods to the prediction of power distributions in PWR's is discussed. Questions relating to choice of homogenisation procedure, effects of mesh arrangement and spacing, and also energy group representation are examined. Numerical studies on supercells and a start of life condition for a large whole core indicate that straightforward application of a conventional coarse mesh procedure should ab initio be capable of achieving about 3 per cent accuracy in local rating. The effects of power-dependent feedbacks and the importance of three-dimensional calculations are illustrated.