CFD modeling of the EPR primary circuit

The present paper deals with the feasibility of a RANS CFD computation of almost all of the primary circuit of a EPR PWR reactor. The developed model includes the vessel, the core, the steam generators and the associated piping. The flow in the primary circuit is studied under normal operations with balanced flow rates between loops. The k-ɛ realizable model is retained for the turbulence modeling, and standard wall functions are used as wall treatment. The constructed grid contains about 181,000,000 elements, mainly hexahedrons. The computation is performed with the commercial CFD code STAR-CD, and despite the relatively large amount of cells, such kind of computation is fully accessible at an industrial scale with today available computational resources. A comparison with experimental data of the obtained results is carried out. The simulation results in the vessel are confronted to measurements issued from JULIETTE and ROMEO mock-ups, representative of the EPR lower and upper internals respectively. Regarding the steam generators, a benchmark with the dedicated code GENEPI is also performed. An overall good agreement with the reference data is underlined. The potential up-and-downstream effects of the different modeled components brought interesting knowledge, especially with regards to safety issues. These encouraging results allow in testing, in a near future, this model in other configurations such as unbalanced operation or accidental transients.