Verification and validation are essential components of the nuclear data development process, since only those data that have been demonstrated to accurately simulate real-life applications can be relied upon for those applications. While most nuclear data work initially relies on so-called 'differential' measurements (e.g. a cross section for a specific reaction at a specific energy for a specific isotope), systems like nuclear reactors require complete physics for all reactions, energies and isotopes. We refer to data taken from full systems as 'integral' data and for nuclear data evaluations to be useful they must ultimately match with integral experiments that are representative of the applications we want to simulate.
Nuclear data verification and validation has been central to the mandate of the Working Party on International Nuclear Data Evaluation Co-operation (WPEC) since its creation in 1989. In the recent years efforts have been made to more closely integrate the benchmark databases of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Evalaution (IRPhE) Project, using these data to pin-point areas for improvement that will have an impact on applications of interest.
Recent subgroup of the WPEC have included the Validation of Nuclear Data Libraries (VaNDaL) project, which has worked on consolidating, harmonising and providing quality assurance methods for the input suites of benchmarks used for nuclear data validation.