239Pu decay heat evaluation

Based on recent measurements, a new evaluation for the decay heat from 239Pu was obtained. The results are important for 239Pu-fueled fast breeder reactors where decay heat values have previously been obtained from summation calculations. The evaluation was, in part, support for a revised ANS decay heat standard for light water reactors. The same statistical methods used previously in the evaluation of decay heat for the thermal fission of 235U were used here. The new evaluation is typically a few percent higher than values previously calculated from ENDF/B-IV. Final evaluated uncertainties are approx. 4% (1sigma) and reflect discrepancies in the measurements that are shown to exist. 8 references