bellona.org

1aOar TIL that in the Soviet era, the Russians built a series of over 130 nuclear powered, unmanned lighthouses along the northern polar coast. These have since fallen into disrepair. Not all of the original sites are known, and some have been looted including the Strontium-90 cores.
LkpYd TIL that in former soviet territories there are hundreds of small, abandoned nuclear generators (250W tops) in total disrepair.
gwr4 TIL that the Soviets dumped 17,000 containers of nuclear waste, 14 nuclear reactors, and more in the Kara Sea. Including one submarine that may re-achieve criticality and explode.