Nuclear Risk Emergencies
Descriptions of international nuclear and radiological emergencies from the end of the Fifties to the present day.
On 29 September 1957, near the Russian town of Kyshtym in the southern Urals, one of the steel tanks used to store high-level radioactive waste (HLW) in Chelybinsk – 40, the military installation for the production of materials for nuclear arms, exploded.
The release of fission products into the surrounding area and the scale of the evacuation operation would have probably classed the event - according to the INES scale (International Nuclear Event Scale) - as a level 6 “serious accident”.
On 7 October 1957, on the coast of Cumberland, in Northeast England, a fire broke out in the Windscale plant managed by the UKAEA (United Kingdom Atomic Energy Authority). The accident was caused by overheating, and by the beginning of the fusion process of the fuel in one of the two reactors used to produce plutonium.
The initial release of radioactivity was on 10 October of the same year, and the contamination of milk with radioactive iodine prompted a ban on consumption.
The serious risks posed outside of the site mean this event would have probably been classified as level 5 on the INES scale: accident with wider consequences.
Three Mile Island (1979)
On 28 March 1979, in the nuclear station of Three Mile Island in Pennsylvania (USA), a technical failure in one of the two reactors caused the fusion of one third of fuel, and the release of fission products inside the containment barriers, noble gases as well as a small quantity of iodine into the atmosphere.
Expectant mothers and preschool children resident within 5 miles of the plant were evacuated, for a total of 25,000 inhabitants; residents within a ten miles radius were advised to stay indoors. There were no restrictions on food consumption.
The accident would have probably been classified as an accident “with wider consequences”, level 5 of the INES scale, despite the serious damage to the core of the reactor.
On 26 April 1986, in the nuclear station of Chernobyl, approximately 100 km from Kiev, the explosion of one of the four reactors in operation caused the partial rupture of the cement cover, with the resulting release of radionuclides into the atmosphere. The leak continued for about ten days, causing extremely serious radiological contamination of vast areas of territory.
The evacuation area stretched out over 30 km around the site and involved 135,000 people. The contamination of foodstuffs, livestock and drinking water was accompanied by a restriction on sale and consumption that is still implemented in some areas of the former Soviet Union.
The event was classed as level 7 on the INES scale: Major accident.
In 1987, some inhabitants from the city of Goiânia in Brazil found a source of 137 Cs (alkaline metals in the form of Cesium chloride) left in a disused private hospital.
The attempt to extract the metal from the encasement and the resulting rupture of the cesium chloride source caused its spread among the population due to the fluorescence of the chloride dust. The resulting contamination caused the death of four people as well as numerous cases of radiation burns.
The main radio protective measures involved not only the treatment of the people exposed, but also decontamination operations through the demolition of seven homes and the production of 3,500 m3 of radioactive waste.