A technique for the selection of the fuel pin diameter for a uranium/zirconium alloy-fueled pressurized water reactor

In this paper, uranium metal alloys were previously suggested for use in advanced pressurized water reactors; a method is proposed to select an appropriate fuel rod diameter for a uranium alloy-fueled reactor. The method attempts to isolate effects caused only by the change in pin diameter; therefore, the thermal margin is maintained by holding a constant departure from nucleate boiling ratio for designs. Neutronic optimization is also maintained by holding the hydrogen-to-uranium ratio constant. Operational aspects are conserved by assuming the same cycle length. Burnup uncertainty is removed by using the same discharge burnup. These assumptions allow a rapid determination of an appropriate fuel pin diameter. The procedure considers all cost changes expected, including pump power and capital cost, vessel and containment size changes, and fuel cycle cost changes. The analysis shows that under these constraints, a 10% Zirconium alloy fuel should have a pin diameter similar to but smaller than that of oxide fuel with a similar pitch. The costs appear to be about the same as for oxide-fueled cores. Large advantages, however, may be possible in safety or burnup