Dismountable fuel assembly of a nuclear reactor cooled by light water

A dismountable fuel assembly of a nuclear reactor cooled by light water including a bundle of parallel fuel rods held in a framework formed by one of guide thimbles and solid ties, spacers and end nozzles fixed onto ends of said ones of guide thimbles and solid ties, at least one of said end nozzles being dismountably fixed onto one of said ends of each of said ones of guide thimbles and solid ties, via an end part of said ones of the guide thimbles and solid ties which is engaged in an opening passing through a transverse adaptor plate of said end nozzle, said adaptor plate being associated with quick dismountable means for fixing said one of said guide thimbles and solid ties, said quick dismountable means including:

• (a) a bearing sleeve integral with the end of said one of guide thimbles and solid ties, comprising a bearing rim and at least two first bearing stops separated by at least two first axial passages, said bearing rim and said first bearing stops protruding radially outward and being axially spaced from each other;
• (b) said opening through said adaptor plate having at least two inwardly projecting bearing stops separated by at least two second axial passages and including a bearing surface perpendicular to an axis of said opening, and at least one cavity projecting radially outward;
• and
• (c) a ring coaxially mounted and rotatable around said bearing sleeve in said opening through said adaptor plate, said ring including at least two third bearing stops projecting radially inward and separated by at least two third passages and at least one part elastically deformable in a radially outward direction;
• (d) said stops and said passages of said bearing sleeve, said opening and said ring being so arranged that said bearing sleeve is axially displaceable in said opening up to an operational position in which said bearing rim bears against said adaptor plate around said opening and said ring is insertable in said opening around said bearing sleeve, said third bearing stops of said ring being axially disposed between said first and said second bearing stops and being rotatable between an unlocked position in which said third passages of said ring are aligned with said passages of said opening and a locked position in which said at least one elastically deformable part of said ring is received in said cavity of said opening and said third stops of said ring face said second passages of said opening.