Boiling water reactor fuel unit has handle

摘要

A nuclear fuel element has fuel pins, at least one coolant pipe, a sheath which surrounds the fuel pins and coolant pipe, and a handle unit (20) which fits into the sheath, where the novelties are is that an integral grid in the handle unit (20) has perforations (38) which are sized to prevent debris, e.g. end plugs from damaged fuel pins, from passing through the grid; and the sheath has a greater internal cross-sectional area at the upper end than at the lower end of the fuel element.