BENCHMARKS FOR THE VALIDATION OF THE HEAT TRANSFER CAPABILITIES OF ONE-DIMENSIONAL SYSTEM CODES

The purpose of the reactor cavity cooling system in a nuclear plant is to effectively remove the heat released by the reactor pressure vessel. The reactor cavity cooling system must be able to operate safely in a natural or passive manner, particularly in the case of very high-temperature reactors in order to avoid accidents due to human error or the failure of components. Radiation, convection, and conduction heat transfer, as well as natural circulation, are the major natural phenomena that determine the performance of a reactor cavity cooling system. System codes are often used to simulate the operation of a reactor cavity cooling system under various conditions. It is important that the codes should be verified and validated. This is achieved by performing carefully controlled experiments and selecting suitable analytical examples. The experiments and analytical examples are modeled using the codes, and the simulation results obtained by the codes are then compared with the corresponding experimental and analytical results. This paper is concerned with two benchmark problems for which the analytical solutions can be obtained and used to validate the heat transfer capability of systems codes to model conduction, radiation, and convection. The systems codes GAMMA+ and Flownex are employed to demonstrate the application of the benchmark problems.