Application of Boron Feedback From BOA CIPS/CILC Analysis on Neutronic Models

This paper summarizes the development of a multi-physics code system for evaluation of Crud Induced Power Shift (CIPS) phenomenon experienced in some Pressurized Water Reactors (PWR). CIPS is an unexpected change in reactor core axial power distribution, caused by boron compounds in crud deposited in the high-power fuel assemblies undergoing subcooled boiling. The approach includes a more robust method compared to previous attempts at coupling codes to account for boron deposition at the nodal level within the neutronic model based on the BOA generated CIPS results. This paper describes the updated linkage with a Python script wrapper around the multi-physics code system ANC9/FUELDUTYDRV/VIPRE-W/BOA. The multi-physics code system can then evaluate changes in core power distributions due to boron deposited in the crud for comparison to measured plant cycle flux trace data. The plant flux trace data provides additional wealth of information for reducing BOA conservatism in the CIPS analysis and benchmarking the multi-physics to the plant-specific source term and plant operation. The linkage of the code system along with the application results will be the base for future development to improve CIPS/Crud Induced Localized Corrosion (CILC) risk for a plant, allowing for the potential benefits of more aggressive fuel management via higher duty cores or improved fuel economics.