A comparative study of MATRA-LMR/FB with CFD on a fuel assembly in PGSFR

Some of its models were modified to be eligible for the analysis of the SFR sub-channel blockage with the wire-wrapped pins. The wire-forcing-function used in the MATRA-LMR, which allocates a forced flow with an empirical correlation for the flow effect of the wire-wrap, was replaced with the Distributed Resistance Model. The Distributed Resistance Model has generally been believed to represent the effect more realistically than the wire-forcing-function. A semi-implicit numerical method was applied to resolve a flow reversal problem, which could not be handled by the former fully implicit method. A code-to-code comparison study was also performed as part of an effort to supplement the qualification. Although MATRA-LMR-FB was qualified based on available experimental data including a code-to-code comparative analysis, it was still hard to say that the level of confidence was enough to apply it to the SFR design with full satisfaction. Additional studies are therefore needed to supplement the qualification of MATRA-LMR-FB. In this study, a code-to-code comparative study was conducted as part of an effort to supplement the qualification of MATRA-LMR-FB. The comparison between MATRA-LMR-FB and the CFD code, CFX, was carried out on a 91-pin fuel assembly based on a 217 pin fuel assembly in a PGSFR to assess the MATRA-LMR-FB prediction capability