Huh. I thought I remembered that they had, and I thought the link agreed with me, but rereading it sounds like they just put a nuclear reactor on a plane and flew it to see if it would kill the crew.
"Between May and August 1961, the Tu-95LAL completed 34 research flights. Much of them made with the reactor shut down. The main purpose of the flight phase was examining the effectiveness of the radiation shielding which was one of the main concerns for the engineers. The massive amount of liquid sodium, beryllium oxide, cadmium, paraffin wax and steel plates; were the sole source of protection for the crew against the deadly radiation emerging from the core."
"Between May and August 1961, the Tu-95LAL completed 34 research flights. Much of them made with the reactor shut down. The main purpose of the flight phase was examining the effectiveness of the radiation shielding which was one of the main concerns for the engineers. The massive amount of liquid sodium, beryllium oxide, cadmium, paraffin wax and steel plates; were the sole source of protection for the crew against the deadly radiation emerging from the core."