EVALUATION OF ACCIDENT TOLERANT FeCrAl COATING FOR PWR CLADDING UNDER NORMAL OPERATING CONDITIONS WITH COUPLED NEUTRON TRANSPORT AND FUEL PERFORMANCE

摘要

Following the Fukushima Daiichi nuclear disaster in 2011, the emphasis for nuclear fuel R&D activities has shifted to enhancing the accident tolerance of light water reactor fuels. In a previous study, several accident tolerant fuel (ATF) designs were evaluated under normal operating conditions for pressurized water reactors with SERPENT and BISON. One of the more promising ATF designs was a fuel rod with Zircaloy cladding and a FeCrAl coating; the current study presents Redwing results for this design. Redwing couples MPACT and BISON in order to perform coupled neutron transport and fuel performance simulations. In both the previous and current studies, a short fuel rod model, 10 pellets in length, was depleted for about 3 years. In the current study, the reactivity as a function of time for the same model was obtained from Redwing; these results show that the FeCrAl coating incurs a significant, but manageable, reactivity penalty. Several important fuel performance parameters were obtained from Redwing and compared to the BISON standalone results from the previous study: fuel/cladding gap width, fission gas released to the plenum, plenum pressure, and other parameters not shown in this paper. The fuel performance parameters show several explainable differences between Redwing and BISON standalone, and some parameters suggest improvements that Redwing makes over BISON standalone. Work is underway to develop a full-length model of an ATF rod for both BISON standalone and Redwing.