Patent Number: 048204757
Section: claims

1. In a cluster assembly including a support plate and at least one burnable absorber rod, an attachment joint for detachably connecting an upper end of said absorber rod to said support plate, comprising: (a) a plug insert defined on said upper end of said rod;  (b) means defining at least one hole through said support plate for receiving said plug insert and defining an annular groove having a concave cross-sectional shape in said support plate within said hole therein;  (c) said plug insert being a cylindrical hollow annular uninterrupted wall disposed within said support plate hole and having a cavity coextensive with the depth of said hole in said support plate for allowing deformation of said wall into conformity with said groove in said hole to provide an interengaging nonthreaded connection to said support plate; and  (d) an enlarged lower flange being solid in cross-section and integrally formed on said upper end of said rod with and below said annular wall of said plug insert to form a bottom of said plug insert cavity at the level of a bottom side of said support plate, said flange being disposed at its upper end in contact with said bottom side of said support plate about said hole such that together with said deformed annualar wall said flange maintains said plug insert in said hole of said support plate;  (e) said annular wall of said plug insert being redeformable out of conformity with the shape of said groove in said hole of said support plate upon application of a predetermined axially-directed force on said plug insert so as to remove said plug insert from said support plate hole and thereby detach said rod from said support plate.