Jean-Claude Amiard - Industrial and Medical Nuclear Accidents

Three plant employees who had been exposed to radiation were transported by helicopter to hospital. The two most affected workers, aged 35 and 39, who reportedly received doses of 16,000–20,000 and 6,000–10,000 mSv, respectively, had symptoms of high radiation that are difficult to treat. About half of those who have suffered radiation at this level face death within 30 days. The two most seriously injured died after 12 weeks and 7 months. The third worker (54 years old) received a lower dose of 1,000–5,000 mSv. According to experts, the chances of this patient’s survival (who was suffering from severe pain) were reasonable, subject to possible complications in the short or long term from severe burns to the arm, head and neck. The quality of care provided to victims has made it possible to prolong their survival beyond what had ever been achieved in accidents of this type and has thus revealed complex and new pathologies [IRS 02].

It was only around 3 a.m. on Friday morning that employees tried to stop the reaction by pumping cooling water around the container and pouring sodium borate to absorb the neutrons. Twenty-four of these employees were seriously irradiated and reportedly received doses above 48 mSv and even up to 120 mSv for one of them. Of the accidentally exposed workers in the plant, 56 were exposed to a dose of 0.1–23 mSv and 21 other workers received high doses when the tank was drained. For members of the public, estimates are highly variable with one receiving 24 mSv, four receiving 10–15 mSv and 15 receiving 5–10 mSv.

Staff at the Lucens power plant was examined at hospital (Hôpital Cantonal de Berne), which revealed that they had not been put at risk. The Atlas of Cancer Mortality in Switzerland prepared by Professors Schüler and Bopp shows an increase in intestinal cancer in the Broye region between 1970 and 1990. Professor Bopp interviewed in “Le Temps” on this subject mentions that “In men, the general excess mortality in the Broye region has the same components as in neighboring regions, namely diseases related to alcohol consumption, accidents and lung cancer. In women, heart disease was the cause of additional deaths. It is therefore impossible to deduce a link with the nuclear damage of 1969, especially since intestinal cancer is not one of the cancers suspected of being caused by radiation” [CAN 11].

Several authors [BRO 82, DEW 87] point out that populations near Three Mile Island (TMI) have developed mental trauma due to anxiety created by unnecessary and careless publicity.

The excess percentage of morbidity caused by the accident for the period 1981–1984 (after a latency of 2 years) was estimated per unit dose (associated with the standard deviation). These percentages were 0.020 ± 0.012 for all cancers, 0.082 ± 0.032 for lung cancer and 0.116 ± 0.067 for leukemias. Adjustments for socio-economic variables increase the percentage estimates to 0.034 ± 0.013, 0.103 ± 0.035 and 0.139 ± 0.073, respectively, for all cancers, lung cancers and leukemias [WIN 97].

According to Talbott et al . [TAL 00], standardized mortality ratios are significantly raised for men and women (SMR 109 and 118, respectively). They also found a significant linear trend between breast cancer risk in women and increasing levels of exposure associated with the TMI accident (p = 0.02). In a subsequent study, the same authors [TAL 03] were more reserved about cancer and radioactivity relationships caused by the TMI accident than in their first article.

In a synthesis conducted 25 years after the accident, Osif et al . [OSI 04] estimated that the health effects resulting from the radiation emitted by the reactor accident were minimal. The only significant effects were on the mental health of local populations. However, the studies carried out only concern a part of the population and over a short period of time. Some effects may appear years or even decades later. For example, 30 years after the TMI accident, an increased incidence of thyroid cancer was observed in counties south of the plant and in high-risk age groups. Average incidence rates between 1990 and 2009 were higher than expected in the counties of York, Lancaster, Adams and Chester [LEV 13]. Despite these findings, a direct correlation with the accident remains uncertain, as incidence rates may coincide with other factors, and the original data were limited [LEV 13].

Following the accident at the Church Rock mine retention basin in New Mexico, the dose for the general population over 50 years is estimated at 2.04 mSv for the inhalation of sediment particles from the river. The same dose is estimated at 0.01 mSv in the liver and 0.79 mSv in the bones when eating wild meat. This suggests that the major contribution to human exposure comes from mine dehydration effluent that has been continuously released into the river system for many years [RUT 84].

The incident involving the breach of radioactive effluents in the sea at La Hague was the subject of a reconstruction of the radiological impact, based on the consumption of marine products by the GRNC [GRN 99]. The calculations were based on two assumptions, and the differences between the results were in the order of a factor of 7 for the collective ex utero dose and a factor of 8 for the collective risk. Whatever the calculation hypothesis considered, the predicted number of leukemia cases, which was in the order of 0.0014 cases between 1978 and 1996 (taking into account only the consumption of marine products), increases to 0.002 if we look at all the exposure routes to discharges from nuclear installations in North Cotentin. This result illustrates the significant sensitivity of the risk of leukemia down to discharges from nuclear installations, particularly with regard to the incident of pipe breakage [BAR 00].

The consequences on exposure ex utero of the two major incidents that occurred at the site of the La Hague spent fuel reprocessing plant (breaking of the offshore discharge pipe in 1979–1980 and fire at silo 181 containing high-level waste on January 6, 1981) were estimated and are presented in Table 2.2.

Table 2.2. Type and level of exposure of the population of Beaumont-Hague caused by incidents at the La Hague spent fuel reprocessing plant (modified according to [GRN 99]. For each of the accidents, the percentages of the various causes are provided

The two accidents at the Chalk River Laboratories in Canada required a major clean-up effort involving many civilians and military personnel (approximately 850). Health surveillance of these workers did not seem to reveal any negative impact of the two accidents [WER 82]. However, some cleaning workers who were part of the military contingent assigned to the NRX reactor applied unsuccessfully for a military disability pension as a result of health damage.