The nuclear reactors shut down Being_in_operation safely .

The Chernobyl Nuclear Power Plant sarcophagus was built Building and finished Process_end by December 1986 , and would also provide Supply radiological protection Preventing_or_letting for the crews of the undamaged Destroying reactors at the site , with No .

The accident Catastrophe prompted Cause_change_of_position_on_a_scale safety upgrades on all remaining Temporary_stay Soviet-designed RBMK reactors , of which 10 continue to be operational .

This mission goal was not met , with the reactors of the research facility only slightly damaged Damaging , although many of the secondary targets were hit Attack .

The tsunami caused Causation nuclear accidents , primarily the level 7 meltdowns at three reactors in the Fukushima Daiichi Nuclear Power Plant complex , and the associated Motion evacuation zones affecting Influence hundreds of thousands of residents .

Many electrical generators were taken down , and at least three nuclear reactors suffered Catastrophe explosions Destroying due to hydrogen gas that had built Building up within their outer containment buildings after cooling system failure resulting Causation from the loss of electrical power .

On detecting Know the earthquake , the active reactors automatically shut down Being_in_operation their fission reactions .

Because of the reactor trips and other grid problems , the electricity supply failed , and the reactors ' emergency diesel generators automatically started Process_start .

Critically , they were powering Supply the pumps that circulated coolant through the reactors ' cores to remove Removing decay heat , which continues after fission has ceased Process_end .

All told , some 154,000 residents evacuated Escaping from the communities surrounding the plant due to the rising off-site levels of ambient ionizing radiation caused Causation by airborne radioactive contamination from the damaged reactors .