Refinement of the Pseudosource Method of Calculating RBMK Cluster Cells

Abstract

The KLARA option is now being used to perform multigroup calculations of VVER and RBMK cluster cells and to prepare few-group characteristics of cells in the WIMS-SH-2.0 and SVL systems. The transition to 69-group calculations of RBMK cluster cells has revealed instability. Analysis has shown that the instability is associated with a discrepancy in the type of pole in several integrals arising in the calculation of the angular moments of the sinusoidal components of the Greens function. The removal of this singularity by adding two lines of the angular moments of the sinusoidal components eliminated this instability. The difference of K_∞ calculated using the KLARA and PIJ options was less than 0.2% for cluster cells with and without fuel.