Fuel bundle with partial length fuel rods and extension members

摘要

In a fuel bundle for a boiling water nuclear reactor comprising a plurality of fuel rods (20'') secured within an array and extending between upper and lower tie plates, and including at least one additional partial length fuel rod (20') extending from said lower tie plate but terminating short of said upper tie plate, an improvement in the form of a removable extension rod (32) secured to said at least one additional fuel rod (20') and extending substantially to said upper tie plate. The removable extension rod also permits variance in the reactivity of the partial length fuel rod particularly in the two phase region of the bundle.