Kyshtym disaster

As a result of the explosion, the cooling system of the remaining radioactive waste tanks was damaged.

An excerpt from the article 42 facts about Kyshtym disaster

A meter-long mound of earth was prepared at the epicenter of the explosion. Then Soviets drilled into the remaining cooling chambers and flooded them with water.

It is worth mentioning that at the same time, the reactor continued to operate, and its shutdown was not considered at all. Moreover, new reactors were being erected, increasing the production of weapons-grade plutonium.

A kilometer-long column of red-orange smoke rose above the tank that exploded.