<P> The world 's worst nuclear accident has been the 1986 Chernobyl disaster in the Soviet Union , one of two accidents that has been rated as a level 7 ( the highest ) event on the International Nuclear Event Scale . Note that the Chernobyl disaster may have scored an 8 or 9 , if the scale continued . The accident occurred at the Chernobyl Nuclear Power Plant after an unsafe systems test led to a rupture of the reactor vessel and a series of steam explosions that destroyed reactor number four . The radioactivity plume spread to the surrounding city of Pripyat and covered extensive portions of Europe with traces of radioactivity , leaving reindeer in Northern Europe and sheep in portions of England unfit for human consumption . A 30 kilometres ( 19 mi ) `` Zone of alienation '' has been formed around the reactor . </P>
<P> The world 's worst nuclear accident has been the 1986 Chernobyl disaster in the Soviet Union , one of two accidents that has been rated as a level 7 ( the highest ) event on the International Nuclear Event Scale . Note that the Chernobyl disaster may have scored an 8 or 9 , if the scale continued . The accident occurred at the Chernobyl Nuclear Power Plant after an unsafe systems test led to a rupture of the reactor vessel and a series of steam explosions that destroyed reactor number four . The radioactivity plume spread to the surrounding city of Pripyat and covered extensive portions of Europe with traces of radioactivity , leaving reindeer in Northern Europe and sheep in portions of England unfit for human consumption . A 30 kilometres ( 19 mi ) `` Zone of alienation '' has been formed around the reactor . </P>
the most damaging nuclear power plant accident occured at
the most damaging nuclear power plant accident occured at
Chernobyl
Chernobyl