Adjoint Sensitivity Analysis of Coupled Thermal-Hydraulics/Neutron-Kinetics Codes: The RELAP5/PANBOX/COBRA System

This work highlights ongoing developments of the RELAP5/PANBOX/COBRA (R/P/C) code system for the analysis of postulated transient reactor safety problems. On the one hand, the validation program of the R/P/C system has continued using international benchmarks. On the other hand, we have derived and numerically solved the adjoint sensitivity system corresponding to the two-fluid model in RELAP5/MOD3.2. Within our ongoing program to validate this adjoint system, we present here typical sensitivity analysis results for the well-known RELAP5 benchmarks that describe the flow of water through two loops with pumps. (author)