Oh, heck yeah! That was Cosmos 954. The recovery effort was a joint US-Canadian operation dubbed “Operation Morning light.” The recovery teams scoured an area of about 48,000 square miles. One of the recovered pieces emitted 500 R/h.
The US Air Force Museum in Dayton once hosted an exhibit of Soviet space items. Fascinating stuff. But I seem to recall they used onboard reactors more often than not.