Читать книгу Industrial and Medical Nuclear Accidents - Jean-Claude Amiard - Страница 27

The question is relatively simple but the answer is complex and subject to variation depending on sources [SOV 08, ROG 11, LEL 12, HAD 14, ASN 16]. Some of the discrepancies result from the criteria used to measure the severity of an accident. Is it the number of immediate deaths? Is it the amount of radioactivity released into the environment? Is it the area of land that has been condemned for centuries?

In the absence of a comprehensive and public reference list of nuclear accidents, we have reconstructed the history of nuclear accidents in power plants from scientific literature and various public sources.

The list of significant events classified at various levels on the INES is similar depending on the source for severity levels 6 and 7. On the contrary, for the lower levels, the lists diverge greatly. For information purposes, we provide in Table 1.4 those from the ASN [ASN 16]. The ASN thus retained two level 7 accidents, one level 6 accident, one level 5 accident, six level 4 accidents and 16 level 3 incidents.

Table 1.4. List of nuclear accidents in the civil field classified in order of decreasing severity according to the INES classification (severity 7 to 3). Significant events classified by the ASN [ASN 16] and by the IRSN [IRS 17e]

Year	Site	Country	Case
Level 7
1986	Chernobyl	Ukraine	Explosion of reactor 4 at the nuclear power plant
2011	Fukushima	Japan	Explosion of reactors 1, 2 and 3 at the nuclear power plant
Level 6
1957	Kyshtym	USSR	Explosion of a radioactive product tank at the reprocessing plant
Level 5
1979	Three Mile Island	USA	Partial fusion of the reactor core
Level 4
1973	Windscale	UK	Release of radioactive materials following an exothermic reaction in a tank during reprocessing
1980	Saint-Laurent-des-Eaux	France	Damage to the A2 reactor’s core
1999	Tokai-Mura	Japan	Criticality accident in a fuel manufacturing facility
2006	Fleurus	Belgium	Irradiation by a cobalt 60 source of a worker working in an ionizing radiation sterilization facility
2010	New Delhi	India	Discovery of radioactive materials in scrap metal stores and irradiation of a scrap metal dealer
2011	Use of radiography	Bulgaria	Irradiation by a cobalt 60 source of four workers involved in an ionizing radiation sterilization facility
Level 3
1981	The Hague	France	Fire in a storage silo
1991	Smolensk	Russia	Exceeding the operating boundary conditions during restart tests following a maintenance shutdown of reactor 2 at the nuclear power plant
1992	Sellafield	UK	Nitrated plutonium leak in a containment cell at the Sellafield fuel reprocessing facility
1993	Narora	India	Loss of power supply to reactor 1 at the nuclear power plant
1993	Kola	Russia	Emergency shutdown of reactor 1 at the nuclear power plant
2002	Roissy	France	Incident during the transport of a package by Federal Express between Sweden and the United States via Roissy airport
2002	Davis–Besse	USA	Discovery of a cavity in the vessel cover on the power plant reactor due to boric acid corrosion of the metal
2002	New Orleans	United States	High dose rate measured on a package from Sweden containing iridium 192 sources
2003	Paks	Hungary	Release of radioactive gases from cracked fuel rods stored in a cleaning tank located next to the fuel pool at the plant
2004	Puerto Rico	Puerto Rico	Irradiation by a cobalt 60 source of two workers involved in an ionizing radiation sterilization facility
2005	Sellafield	UK	Detection of a radioactive leak on a pipe in the THORP fuel reprocessing facility
2008	Toulouse	France	Irradiation by a cobalt 60 source of a worker working in an irradiation bunker on the ONERA site
2008	Fleurus	Belgium	Abnormal release of iodine 131 from the chimney of the Institut des radioélements building during a transfer of liquid effluent between tanks
2008	São Paulo	Brazil	Irradiation of an American and a Brazilian worker during the replacement of the cobalt 60 source of a cobalt therapy device in a state hospital

Level 7 is used by all for the Chernobyl accident [IAE 13] and Fukushima [IRS 17e], level 6 for Kyshtym and level 5 for Three Mile Island [IAE 13]. On the contrary, the ASN [ASN 16] classifies the 1957 Windscale accident as level 4 and the IAEA [IAE 13] as level 5. In its list, the ASN ignores the Goiânia accident in Brazil in 1987 [IAE 13] and the accident at the Chalk River nuclear laboratories in Canada in 1952 [MOR 15], classified at level 5.

The ASN ignores the accident of October 17, 1969 in Saint Laurent with the fusion of 50 kg of uranium from the Saint-Laurent-A1 nuclear power plant in France during loading [IRS 15a]. Similarly, the ASN ignores the core fusion at the Lucens nuclear power plant in Switzerland on January 21, 1969 [CAN 11], classified at level 5 by the OFPP (Office fédéral de la protection de la population) [OFP 15]. The ASN [ASN 16] classifies the Fleurus accident (Institut national des radioélements) in Belgium in 2006 as level 3 and the IAEA [IAE 13] as level 4.

The level 3 incidents reported by the various official sources widely differ. While the ASN retains the Sellafield accident in 2005 [IAE 13] and the silo fire in The Hague in 1981 [FRA 14], several incidents reported by the IAEA [IAE 13], such as the loss of a source causing severe burns in 1999 in Yanango (Peru) or the same year in Ikitelli (Turkey) [IAE 13], are ignored. Further examples are the exposure of a worker to a radioactive source at ONERA in Toulouse (March 18, 2008) and of three temporary employees who entered an industrial accelerator in operation and were heavily irradiated in Forbach (Moselle) in 1991 [IRS 17e]. This was also the case for a radioactive leak (¹⁹²Ir) from a drum shipped from Sweden to the United States, transiting through Roissy (December 2001–January 2002) [ANO 02].

The most serious nuclear accidents involving reactors are those involving the melting of the fuel contained in their core. From an analysis of the various lists of nuclear accidents [SOV 08, ROG 11], we can consider that at least 12 reactors have been destroyed by this phenomenon since 1952. These are the Windscale plutonium cell (United Kingdom) in 1957 (but which we classified as a military accident), the Chalk River CANDU reactor (Canada) in 1958, the Simi Valley sodium-cooled experimental reactor (California) in 1959, the Monroe sodium-cooled demonstration breeder reactor (Michigan) in 1966, the Chapelcross reactor (United Kingdom) in 1967, the Lucens experimental reactor (Switzerland) in 1969, the pressurized water reactor at Three Mile Island (Pennsylvania) in 1979, the graphite-gas A2 reactor at Saint-Laurent-des-Eaux (France) in 1980, the Chernobyl reactor (Soviet Union) in 1986 and the three reactors at Fukushima (Japan) in 2011.

These are not the only reactors whose cores have suffered. For example, according to Wing and Hirsch [WIN 06], at least four of the reactors located at the Santa Susana Field Laboratory (SSFL) site have suffered such accidents. These are the AE6 reactor which suffered a release of gaseous fission products into the environment in March 1959, the SRE which had a power excursion and partial core meltdown in July 1959, the SNAP8ER which in 1964 suffered 80% damage to its nuclear fuel and the SNAP8DR which in 1969 suffered similar damage to one-third of its nuclear fuel. Let us also recall the accident in 1961 of the Idaho Falls SL-1 experimental reactor discussed in the previous volume [AMI 19], or that of the Jaslovske Bohunice reactor (Czechoslovakia) in 1977, but where the consequences were much more limited.

For nuclear workers, the number of accidents with clinical consequences is limited and tends to decrease for criticality accidents. On the contrary, the number is greater and tends to increase for accidents with radionuclides and especially for accidents related to sealed sources (Figure 1.2).

Figure 1.2. Trends in the various types of nuclear and radiological accidents with clinical consequences for nuclear workers (adapted from [UNS 00a]). For a color version of the figure, see www.iste.co.uk/amiard/industrial.zip