Uncertainties in Fission Product Decay-Heat Calculations

Based on a sensitivity analysis of decay-heat summation calculations, uncertainties are obtained for the calculated decay heat associated with the thermal fission of ²³⁵U and the fast fission of ²³⁸U and ²³⁹Pu. For typical reactor irradiation times and cooling times >100 s, these uncertainties are <3.5% for ²³⁵U, 4% for ²³⁸U, and 5% for ²³⁹Pu. All calculations are based on ENDF/B-IV data.