Multiphysics Methods for Improved Safety Evaluations of Reactor Systems
The main goal of multiphysics methods for the core analysis is to improve the description of both core thermal hydraulics and neutronics by using improved solvers with detailed spatial resolution and better physical models.
The new coupled codes can be applied for the core analysis of both BWR, VVER and PWR, where a non-symmetrical core behaviour is expected to occur e.g. in case of a REA, MSLB, boron dilution, ATWS, etc. The advanced coupling approaches at pin /subchannel level based on both deterministic and stochastic methods facilitate the direct prediction of safety parameters e.g. fuel enthalpy, maximal cladding temperature, DNBR, MCPR, maximal fuel temperature, etc. by considering the local feedbacks between neutronic and thermal hydraulics. They can provide reference solutions for lower order solutions based on nodal diffusions solvers and pin power reconstruction.
The validation of the multiphysics codes is performed using international benchmarks such as the OECD NEA Kalinin, UAM Benchmark, VVER-1000 Coolant transient benchmarks, etc.
At KIT, the following coupling options are being evaluated, improved and developed: