Development and Benchmarking of the DYN3D/RELAP5 Code System

The integration of advanced computer codes from different safety analysis areas into code systems of expanded modeling capabilities results in a more detailed and accurate representation of reactor plant structural components. Less conservative predictions of advanced codes are needed to analyse the transients of LWRs. As a result of the joint FZR-IPPE research project, the coupled code system DYN3D/RELAP5 has been developed. The incorporation of the DYN3D spatial kinetics model into the RELAP5 code overcomes the restrictions of the stand-alone codes. AER-5 benchmark calculations for the VVER-440 reactor plant have been performed to validate the code. Code-to-code comparison (DYN3D/RELAP5-DYN3D/ATHLET) of simulation results shows a good agreement and confirm a validity of the developed internally coupled code system.