Table 18.8 - Severe nuclear accidents (level 6 to 7 of INES scale)
Source: IAEA, 1991; SCOPE, 1993
| Location | Kyshtym (Eastern Urals) | Chernobyl (Ukraine) |
|---|---|---|
| Date | September 1957 | April 1986 |
| Estimated radioactivity release (TBq) | 740 000 | 2 million |
| Nature of plant | Chemical processing | Electricity generation |
| Main radionuclides of concern | Ce-144, Pr-144 (short term) Sr-90 (long term) | I-131, Cs-134, Cs-137 and rare earths |
| Mode of release | Instantaneous (chemical explosion) | Over some days (criticality explosion and subsequent phenomena) |
| Significantly contaminated area | Some 20 000 km2 | Some 20 000 km2 |
| Affected area | | Northern hemisphere |
| People evacuated | 11 000 | 116 000 (first year after accident) |