This was immediately followed by an open-air reactor core fire that released considerable airborne radioactive contamination for about nine days that precipitated onto parts of the USSR and western Europe , before being finally contained Containing on 4 May 1986 .

To reduce Cause_change_of_position_on_a_scale the spread Dispersal of radioactive contamination from the wreckage Catastrophe and to protect Preventing_or_letting the site from further weathering , the remains of reactor No .

4 reactor were further enclosed in 2017 by the Chernobyl New Safe Confinement , a larger enclosure that allows Preventing_or_letting the removal of both the sarcophagus and the reactor debris , while containing the radioactive hazard .

Operation Military_operation Peppermint was the codename given Giving during World War II to preparations by the Manhattan Project and the European Theater of Operations United States Army ( ETOUSA ) to counter the danger that the Germans might disrupt the June 1944 Normandy landings with radioactive poisons .

The partial meltdown resulted in Causation the release of radioactive gases and radioactive iodine into the environment .

The partial meltdown resulted in Causation the release of radioactive gases and radioactive iodine into the environment .

Castle Bravo 's yield was 15 megatons of TNT , 2.5 times the predicted 6.0 megatons , due to unforeseen additional reactions involving Cause_to_be_included Li , which led to Causation the unexpected radioactive contamination of areas to the east of Bikini Atoll .

The bomb for Operation Hurricane was assembled Come_together ( without its radioactive components ) at Foulness , and taken Conquering to the frigate for transport Sending to Australia .

In the 1950s , a series of large thermonuclear tests rendered Causation Bikini unfit for subsistence farming and fishing because of radioactive contamination .

The `` Baker '' test 's radioactive contamination of all the target ships was the first case of immediate , concentrated radioactive fallout from a nuclear explosion .

The `` Baker '' test 's radioactive contamination of all the target ships was the first case of immediate , concentrated radioactive fallout from a nuclear explosion .

The weapons ' multiple safety interlocks prevented Preventing_or_letting both a nuclear explosion Catastrophe and release of radioactive material .

The resultant loss-of-coolant accidents led to Causation three nuclear meltdowns , three hydrogen explosions , and the release of radioactive contamination in Units 1 , 2 and 3 between 12 and 15 March .

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 .

Large amounts of water contaminated with radioactive isotopes were released into the Pacific Ocean during and after the disaster .

Michio Aoyama , a professor of radioisotope geoscience at the Institute of Environmental Radioactivity , has estimated Statement that 18,000 terabecquerel ( TBq ) of radioactive caesium 137 were released into the Pacific during the accident , and in 2013 , 30 gigabecquerel ( GBq ) of caesium 137 were still flowing Motion into the ocean every day .

The site was contaminated Destroying with radioactive materials and an initial cleanup Emptying was attempted in 1967 .

The bomber crashed Destroying onto sea ice in North Star Bay , Greenland , causing Causation the conventional explosives aboard to detonate Attack and the nuclear payload to rupture Destroying and disperse Dispersal , which resulted in Causation radioactive contamination Bodily_harm .

The blast Catastrophe is generally estimated to have had an explosive force of less than one kiloton , and some radioactive output was detected Check .