This work contributes to the Hydride Fuels Project, a collaborative effort between UC Berkeley and MIT aimed at investigating the potential benefits of hydride fuel use in light water reactors (LWRs). Core design is accomplished for both hydride and oxide-fueled cores over a range of geometries via steady-state and transient thermal hydraulic analyses, which yield the maximum power, and fuel performance and neutronics studies, which provide the achievable discharge burnup. The final optimization integrates the outputs from these separate studies into an economics model to identify geometries offering the lowest cost of electricity, and provide a fair basis for comparing the performance of hydride and oxide fuels. This work focuses on the steady-state and transient thermal hydraulic as well as economic analyses for PWR cores utilizing wire wraps in a hexagonal array with UZrH1.6 and UO2. It was previously verified that square and hexagonal arrays with matching rod diameters and H/HM ratio have the same thermal hydraulic performance. In this work, this equivalence is extended to hexagonal wire wrap arrays, and verified by comparing the thermal hydraulic performance of a single hexagonal wire wrap core with its equivalent square array core with grid spacers. A separate neutronics equivalence is developed, based on the assumption that arrays with matching rod diameters and H/HM ratios will have identical neutronic performance. Steady-state design limits were separated into hard limits, which must be satisfied, or soft limits, which serve to keep the design reasonable. Design limits were placed on the pressure drop, critical heat flux (CHF), vibrations, and fuel and cladding temperature. Vibrations limits on the wire wrap assemblies were imposed for flow induced vibrations (FIV) and thermal hydraulic vibrations (THV).
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