Consequences of sodium bond loss from an LMFBR carbide fuel element

The consequences of sodium bond loss from a uranium-plutonium carbide fuel element during normal steady state operation have been assessed. The elements considered are typical of those currently being irradiated in EBR-II, and include elements with and without shroud tubes. The analysis presented is very conservative in that the many simplifying assumptions required were made to predict worse consequences than would be found in a realistic analysis. Following sodium bond loss, fuel melting occurs, but the fuel rapidly resolidifies after slumping out to contact the clad. Even if molten fuel were lost through an existing clad failure, the maximum fuel temperatures attained are below those required to initiate a vapor explosion in the sodium coolant. The small amount of molten fuel that might escape through an existing clad failure would have little or no effect on adjacent elements. (auth