Effects of Nuclear Data Uncertainties on the NEA/OECD PWR MOX/UO₂ Core Rod Ejection Benchmark

The effects of nuclear data covariance on the rod ejection transient of the pressurized water reactor mixed-oxide/UO₂ core benchmark sponsored by the Organisation for Economic Co-operation and Development/Nuclear Energy Agency and the U.S. Nuclear Regulatory Commission are investigated. For this purpose the uncertainty and sensitivity software package XSUSA developed at Gesellschaft für Anlagen- und Reaktorsicherheit is applied to propagate uncertainties in nuclear data libraries to the transient calculations. A statistically representative set of transient calculations is analyzed, and both integral and local output quantities are compared with the benchmark results of different participants. It is shown that the uncertainties in nuclear data play a crucial role in the interpretation of the simulation results. The work is a step forward in establishing a methodology that combines best-estimate calculation with performing uncertainty analysis for coupled full-core calculations.