A demonstration-only end-plate from one of the 19-element fuel bundles used in the NPD reactor. Initially NPD was loaded with 7-element bundles but these were later replaced by 19-element bundles that operated at higher power rating. The lower left-hand photo, (taken from “A Description of NPD” – an illustrated talk presented at the Seventh AECL Symposium on Atomic Energy, Chalk River, September 18, 1961 by J. L. Olsen of CGE) shows the bundles with and without packing as received at NPD while the right-hand photo taken from NPD files shows more details of the end of an early design of 19 element bundle. The end-plate at the top, for a later design of 19-element bundle, was modified for easier welding on to the ends of the fuel elements.
