Maybe they were thinking about generating their own electricity and getting off the power grid. Hard to imagine we can track Iran's program and fuel while the AEC somehow lost track of 3.5 lbs of material. I smell a coverup. Maybe a project to see if it was possible to develop a system to see what it would take to fog beyond use film used in spy planes.
I do wonder if other lage US companies may have similar little gems in their basements. Maybe someone like Dell trying to develop a miniture reactor to put into its laptops eliminating the need for batteries or, Chrysler developing a nuclear powered car; remember they developed the turbojet experimental cars.