Reactor physics and design code issues

Reactor physics methodology required for burnup credit is drawn from two major areas of analytical endeavor. The isotopic composition of the spent fuel is determined through reactor burnup analyses. The reactivity worth of the spent fuel in a particular cask design configuration is determined through cask criticality analyses. The purpose of this paper is to provide a brief introduction to potential issues involved in characterizing spent fuel and its reactivity worth, and to provide a brief review of major design code packages which are suitable for performing these analyses. A more detailed discussion of the point-reactor burnup and criticality methodologies is given. A general exposition of multidimensional reactor-burnup methodology as practiced in the power reactor industry is also presented