The NPD was the prototype and proving ground for research and development that led to commercial application of the CANDU system for generating electric power from a nuclear plant using natural uranium fuel, heavy water moderator and coolant in a pressure tube configuration with on-power refuelling.

It was situated close by the AECL research establishment at Chalk River and the HEPC hydro generating station at Des Joachims, Ontario.

Equally important, NPD was the training and simulation center for generations of Canadian and off-shore CANDU operations staff.

The first nuclear-produced power in Canada was generated at NPD, which also served as the "proof of concept" prototype for the later CANDU designs.

As with all commercial CANDU units to follow, NPD operated with natural uranium fuel in a horizontal pressure-tube core, was both moderated and cooled by heavy water, and was refuellable on-load.