A Design Study on the FBR Metal Fuel and Core for Commercial Applications

Abstract

A design methodology for the FBR metal fuel and core is developed. It consists of the fuel integrity prediction by a mechanistic analysis code, and the core neutronic/thermal-hydraulic design in which the effect of the characteristic fuel behavior and fuel cycle technologies are properly considered. Based upon this methodology, a fuel and core design study for reactors of various output scale (150–1500 MWe) is conducted, and the feasibility of metal fuel FBRs for the future commercial applications is reviewed. The results show that the averaged burnup of as high as 90–150 MWd/t is achievable at the refueling interval of 1–2 years with 3–4 batches, regardless of the output scale. The maximum allowable cladding temperature is assumed to be 650°C to avoid the liquid phase formation, which leads to the achievable core outlet temperature of ∼510°C based on the current hotspot factors estimation. It is found that high breeding ratio of ≥1.2 can be enabled with relatively small blanket amount, owing to the very high internal conversion capability. Another advantage is that it is possible to significantly reduce the burnup reactivity loss at the slight expense of the burnup, in which case the core excess reactivity becomes as small as a few dollars.