NUCLEAR ENERGY AGENCY

Commission (NRC) sponsorship a PWR main steam line break (MSLB) benchmark against coupled system thermal-hydraulic and neutron kinetics codes. The benchmark was very well received internationally. It was felt among the participants that there should be a similar benchmark against the codes for a BWR plant transient. The turbine trip (TT) transients in a BWR are pressurisation events in which the coupling between core phenomena and system dynamics plays an important role. In addition, the data made available from experiments carried out at the plant make the present benchmark very valuable. The NEA and US NRC have approved it for the purpose of validating advanced system best-estimate analysis codes. A small team at Pennsylvania State University (PSU) was responsible for authoring the final specifications, and will be in charge of co-ordinating the benchmark activities, answering the questions, analysing the solutions submitted by benchmark participants and providing reports summarising the results for each phase. In performing these tasks the PSU team is collaborating with Andy M. Olson and Kenneth W. Hunt from PECO Nuclear. Lance J. Agee, EPRI, is also providing technical assistance for this international benchmark project. Three benchmark workshops are scheduled during the course of the benchmark activities. The first workshop was conducted for the participants in the exercises concerning the BWR TT transient, an