Patent Number: 041982720
Section: claims

1. In a liquid metal cooled fast breeder nuclear reactor having a fuel assembly support structure, and a peripherally restrained up-standing fuel sub-assembly, the improvement wherein said sub-assembly comprises: a bundle of spaced nuclear fuel pins;  a tubular wrapper enclosing said bundle of fuel pins;  a spike extension for the tubular wrapper for plugging the fuel sub-assembly into said fuel assembly support structure, said spike extension comprising a sleeve having axially spaced cylindrical surfaces defining spigots for engaging vertically spaced sockets in the fuel assembly support structure;  said sleeve being spaced from said wrapper and having an end region enclosed by an end region of the wrapper to define an annular clearance therebetween; and  an elongate resilient tie member pivotably connecting the tubular wrapper and sleeve, the tie-member extending through the sleeve and having one end rigidly secured to the wrapper and another end rigidly secured to the sleeve. 2. An improved nuclear reactor according to claim 1 wherein the sleeve carries resilient split rings for sealing against liquid metal cooling flow between the wrapper and sleeve.