Verification and Analysis of CSR1000 Subchannel Code with Wire Wrap Model

Wire wrapped rod bundles were generally adopted by SCWR fuel assembly design. The wire wraps may have complicated impact on the thermal hydraulic behaviors of the rod bundle. In this paper, some improvements have been made on the geometry identification of the wire wrap model based on the subchannel code ATHAS and the results were compared with the CFD code. The improved subchannel code can generally reflect the thermal hydraulic behaviors of each subchannel and make reasonable response to the variation of geometry factors. The improved subchannel code is physically reliable, however, more work needs to be done to improve its accuracy.