The University denies any of it happening.
But, these are Canadians, probably liberals too. Don't trust em.
Would it be possible that they didn't walk out with waste that the reactor was known to have generated, but rather with other material that they had brought in and exposed to the radiation in the reactor. If they brought in some U-238 (the most common isotope of uranium) they could irradiate it in the reactor and make themselves some plutonium.