The bombs dropped on Hiroshima and Nagasaki and the atmospheric bomb tests carried out in the 1950’s and ‘60’s were the tragic results of deliberate and premeditated actions. Many of the releases of radiation from the military or civilian nuclear industry, however, are well and truly accidental.
Nuclear accidents in the military date back to the early days of the arms race, when the major powers – the United States, the Soviet Union and Great Britain – developed their atomic weapons in the greatest possible secrecy (*).
These early accidents were the result of a combination of lack of experience, ignorance of many relevant phenomena, and a general disregard for necessary safety precautions. Possible environmental consequences did not rate very highly when compared to the strategic objectives. Many tests, especially in the Soviet Union, were carried out in previously unspoiled natural areas. This seemed the obvious way to minimise the danger caused by the generally lax safety protocols.
These accidents were due to a lack of experience that onehad at the time, to ignorance of certain phenomena and also to a lack of precautions. Environmental preoccupations did not carried much weight against strategic objectives.
It was this mindset that led to the contamination of the Techa River in the Southern Urals. Radioactive waste stockpiled in lakes at the Mayak reactor site leaked out when the cold caused the containers to burst, and the area suffered from the consequences from 1949 to 1956.
IThe 1957 graphite fire at the Windscale power plant (better known as the Sellafield reactor) would have had far less dramatic consequences if the English engineers had known about the Wigner Effect, a then comparatively recently-discovered phenomenon. Many of these accidents which took place on old military sites were understandably late to emerge – especially those which took place in the old Soviet Union.
The Three Mile Island accident, which took place near Washington DC, resulted in the destruction of a reactor but fortunately caused comparatively little environmental contamination. The traumatic effect it left on the American psyche was mainly due to the precautionary displacement of several hundreds of thousands of people. The security systems which prevented the Three Mile Island accident from transforming into anything more serious were also in place on the Chernobyl reactor. The dramatic consequences of Chernobyl were largely the result of the tragic deactivation of the security systems, and the giant radioactive cloud which has come to represent the Soviet disaster would otherwise have been avoided.
The last accident of Fukushima was triggered by the tsunami that devastated Japan in March 2011. The reactors at the plant were shut down but were their cooling systems were drowned. After Three Mile Island, the Japanese disaster has confirmed that defects of a proper cooling after shut down, as well as control of the chain reaction, could be the source of the more severe accidents.
Reactor accidents are not the only ones that can take place, as shown by the 1999 TokaïMura criticality accident. Workers at this Japanese fuel reprocessing facility violated the security regulations that were in place, resulting in a comparatively minor accident nevertheless considered to be the third most serious in the history of nuclear technology.
Last but not least there are the accidents linked to radioactive sources used in medicine, industry, or in laboratories. The risk of exposure mandates a rigorous inspection system, but the small amounts of radioactivity involved limit the potential consequences of such accidents.
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