Abstract: A sleeve assembly for refurbishing a fuel rack having cells in which fresh or spent nuclear fuel assemblies may be stored, in which the cells have elongate rack walls extending from a rack base plate and the rack base plate has flow holes communicating with the cells. The sleeve has at least one elongate wall extending from the topside of a sleeve base having an opposed bottom side. The sleeve base has a flow hole extending therethrough that communicates with one of the rack base plate flow holes. A pin assembly disposed in the sleeve base flow hole has resilient tabs extending beyond the bottom side of the sleeve base for extending into a rack base plate flow hole and resiliently engaging the rack base plate when the sleeve assembly is installed in one of the cells. The pin assembly resists horizontal and vertical movements of the sleeve assembly, permits water flow into the cell and permits sleeve assembly removal tools and inspection devices to access the pin assembly.

Abstract: Spent nuclear fuel assemblies are stacked in a spent nuclear fuel assembly pool by structurally supporting a second tier nuclear fuel assembly storage rack in the spent nuclear fuel assembly pool over and independently of previously installed first nuclear fuel assembly racks. The spent fuel assemblies then are introduced into the second tier fuel assembly storage racks while vertically oriented. The spent nuclear fuel assemblies in some spent fuel pools are at least partially raised out of the spent nuclear fuel assembly pool before being introduced into in the storage racks. In zone loading practices, spent nuclear fuel assemblies from the lower tier nuclear fuel assembly racks are at least partially raised out of the pool and then introduced into in the second tier storage racks.