IAEA CRP benchmark of ROCOM BORON DILUTION and PTS test cases for the use of CFD in reactor design

Over the last 15 years, considerable effort has been expended in assembling the available information on the use of CFD in the nuclear reactor safety field. Typical application areas here are heterogeneous mixing and heat transfer in complex geometries, buoyancy-induced natural and mixed convection, etc., with specific reference to NRS accident scenarios such as Pressurized Thermal Shock (PTS), boron dilution, hydrogen build-up in containments, thermal fatigue and thermal striping issues, etc.
The nuclear industry now also recognizes that CFD codes have reached the desired level of maturity for them to be used as part of the NPP design process, and it is the objective of a IAEA CRP to assess the current capabilities of such codes in this regard, and contribute to the technology advance in respect to their verification and validation. The development, verification and validation of CFD codes in respect to NPP design necessitates further work on the complex physical modelling processes involved, and on the development of efficient numerical schemes needed to solve the basic equations.
Therefore, two sets of ROCOM CFD-grade test data were made available to set up an IAEA benchmark, relating to boron dilution (pump start-up) and Pressurized Thermal Shock (PTS) scenarios. The first experiment deals with boron dilution scenarios during start-up of the first coolant pump. The second benchmark deals with the injection of the relatively cold Emergency Core Cooling (ECC) water which can induce buoyancy-driven stratification
The Benchmark activities will help to analyse the CFD code capabilities for CFD in nuclear reactor design applications.