Plutonium Isotopic Calculations for a Modern Light Water Reactor

The adequacy of the Advanced Recycle Methodology Program for predicting isotopic ratios as a function of exposure is determined for a light water reactor of modern design. For the first time, the capabilities of a two-dimensional multigroup transport theory code have been applied to the calculation of isotopic parameters for a commercial U.S. pressurized water reactor. The calculated results are found to be in satisfactory agreement with benchmark measurements. However, captures in seem to be underpredicted when ENDF/B-IV (or ENDF/B-III) resonance parameters for the 1.056-eV resonance are used in the calculations.