How was the ukraine nuclear power disaster fixed?

Answer 1

Actually, it has not been "fixed".

During the days following the accident, many workers were sent in to evacuate people, and to do "cleanup". These workers were provided with simple dust masks and told that it would provide them with protection. They had no clue how dangerous it was for them.

Afterwards, Russia buried the leaking reactor in concrete. This contained the radiation temporarily. However, the concrete has deteriorated greatly, has developed cracks, and is falling apart.

The Ukraine government is studying how to permanently resolve the issue of the failing concrete containment, but a permanent solution is likely years away.

Answer 2

By heroic firefighters who put out the fire even though they knew the radiation would lead to a painful slow death.
The whole reactor was then buried under thousands of tons of concrete.

Answer 3

They buried the Chernobyl reactor in concrete.... Check out the link below for the details.