Industrial and Medical Nuclear Accidents. Jean-Claude Amiard

06/01/1981 La Hague, France Reprocessing plant (15 years) Fire in a storage silo 16/08/1989 Gravelines, France PWR reactor (9 years) Inadequate screw in the primary circuit’s valve 19/10/1989 Vandellos, Spain Gas-graphite reactor (17 years) Fire of a turbo alternator unit 11/03/1997 Tokai-Mura, Japan Fuel production plant (18 years) Fire and explosion irradiating 37 people 10/04/2003 Paks, Hungary PWR reactor (19 years) Radioactive leakage in the fuel rod cleaning system 21/04/2005 THORP/Sellafield, United Kingdom Reprocessing plant (8 years) Leakage of radioactive liquid following a ruptured pipe 4 21/01/1969 Lucens, Switzerland Heavy water reactor (1 year) Cooling failure resulting in partial fusion of the reactor 17/10/1969 Saint-Laurent-des-Eaux, France Gas-graphite reactor (1 year) Uranium smelting Reactor shutdown for 1 year 26/09/1973 Windscale/Sellafield, United Kingdom Reprocessing plant (22 years) Explosion and release of radioactive materials (37 people irradiated) 07/12/1975 Lubmin, Germany PWR reactor (1 year) Short circuit on the reactor transformer, fire and destruction of cooling pump supply 22/02/1977 Bohunice, Slovakia Gas-cooled heavy water reactor (5 years) Core corrosion and power failure during fuel changeover 13/03/1980 Saint-Laurent-des-Eaux, France Gas-graphite reactor (9 years) Uranium melting and damaged core (corrosion) 30/09/1999 Tokai-Mura, Japan Fuel fabrication plant (22 years) Uranium dosing error and explosion (three irradiated, two deaths) 5 10/10/1957 Windscale Military reactor (11 years) Fire 28/03/1979 Three Mile Island, United States PWR reactor (1 year) Partial fusion of the reactor core 6 1957 Kyshtym, USSR Reprocessing plant (?) Explosion (>10 PBq ¹³¹I) 7 26/04/1986 Chernobyl, USSR (Ukraine) Pressure tube reactor (3 years) Explosion and partial melting of the core 11/03/2011 Fukushima-Daiichi, Japan BWR reactors (36–40 years old) Cooling shutdown and partial core melting of three reactors

2.2.3.1. Accident at the Simi Valley nuclear power plant

      The Santa Susana Field Laboratory (SSFL) was a test site used for rockets and nuclear reactors, located 40 km from the geographical center of the Los Angeles metropolitan area (California), near Simi Valley.

      On July 26, 1959, during the 14th low-power test of the Sodium Reactor Experiment (SRE), following a poor sodium flow, the temperature difference between the various fuel channels was found to be excessively high. After the immediate termination of this test, it appeared that 13 of the 43 fuel elements were damaged [ASH 59, ASH 61].

      The Simi Valley accident has remained relatively unknown and continues to be shrouded in mystery today. As a result of corporate and government secrecy, news of the incident came only 20 years later, and the information provided is few and far between [ROG 12].

      Thus, while Ashley et al. [ASH 59] claim that no radiological hazards were present in the vicinity of the reactor, subsequent information would estimate radioactive releases 240 times higher than those from Three Mile Island [GRO 15]. Similarly, a controversy over iodine 131 releases arose between those who claimed that no iodine releases had occurred as a result of the accident [CHR 05, DAN 05] and those who believed that substantial quantities of iodine had been released into the atmosphere [MAK 05, MAK 06, LEL 12].

Iodine 131 releases were estimated at 1,300 Ci (4.81.10¹³ Bq) by Makhijani [MAK 06]. According to Lelieveld et al. [LEL 12], the radioactive releases from this accident were greater than 200 PBq (without taking into account the supposed substantial emissions of ⁸⁵Kr and ¹³³Xe but without any available data), making this accident one of the most serious, at level 5 or 6 on the INES. Based on the damaged reactor core fraction (30%), the analytical value of the radioactive iodine and cesium fraction released by the damaged fuel (10%) and an empirical value of the efficiency of the ventilation system (10%), Lochbaum [LOC 06] concluded that the fraction of the total cesium inventory in the SRE reactor core at the time of the July 1959 accident reaching the environment was between 0.3% and 30% and the fraction released of radioactive iodine was between 3% and 30%. This author estimated that the 15% value for the amount of iodine released was the most likely.

      2.2.3.2. Accident at the Lucens nuclear power plant

      Construction of a heavy water reactor at the Lucens site in Switzerland began in 1962 (Figure 2.3). It was constructed completely underground, with the exception of a few storage and operations buildings. At the beginning of 1969, after a period of revision, the Lucens power plant reactor was returned to service. On January 21, 1969, when the power was increasing, the pressure in the primary cooling system dropped sharply. The instruments also reported a significant increase in radioactivity in the facility enclosure and a significant loss of heavy water. This meant that the moderator tank was damaged. An emergency shutdown of the reactor was carried out, and the caverns were isolated from the outside by closing the ventilation ducts. A few hours after the accident, radioactivity in the access tunnel decreased and the reactor continued to be cooled. Measurements taken on the night of the accident itself, and subsequently, showed that the level of radioactivity in the vicinity had hardly changed from a background level. After this incident, the facility was completely dismantled and the caverns decontaminated. The dismantling work, the decontamination, the analyses of the causes of the accident,