The only really interesting thing about this is the claim that it was weapons grade uranium. I wonder if they mean the same thing other people do when they say that (for me, 90+% U-235), or if the mention of californium means it was blended?
Also, back in the day it was quite normal for such small research reactors to use HEU (specifically, about 93% enrichment), and such reactors were pretty commonplace at the time. See: http://en.wikipedia.org/wiki/Research_reactor
Cf-252: http://www.nndc.bnl.gov/chart/reCenter.jsp?z=98&n=154
«A steady stream of neutrons is needed for these purposes. Kodak used small research reactors, including one at Cornell University, and possessed a dollop of californium-252, a radioactive isotope that endlessly sheds neutrons.
But it wanted a more potent in-house system, so in 1974 it acquired a californium neutron flux multiplier, known as a CFX. Small plates of highly enriched uranium multiplied the neutron flow from a tiny californium core.»