Validation of a Three-Dimensional Model of EBR-II and Assessment of RELAP5-3D Based on SHRT-17 Test

The International Atomic Energy Agency established a Coordinated Research Project (CRP) for EBR-II shutdown heat removal tests (SHRT). The CRP aims at improving the design and the simulation capabilities in fast reactor neutronics, thermal hydraulics, plant dynamics, and safety analyses. This is achieved by benchmark analyses of protected (SHRT-17) and unprotected (SHRT-45r) loss-of-flow tests, from the EBR-II SHRT program. In this framework, ENEA has set up, applied, and is validating an integrated multiphysics approach, based on existing codes, for supporting the design and the safety analysis of Generation IV liquid-metal fast reactors. This paper outlines the rationale of the CRP participation, and it focuses on the qualification of a three-dimensional (3-D) thermal-hydraulic nodalization of EBR-II and on the assessment of RELAP5-3D code against the test SHRT-17. The nodalization models one by one the fuel assemblies of the core and of the extended core of the reactor for an efficient coupling with a 3-D neutron kinetic analysis code. The experimental data are presented and the thermal-hydraulic phenomena of test SHRT-17 are discussed, being the basis for assessing the code performance and for discussing its limitations. Blind and open calculation results are presented and discussed.