Satellites, nuclear accidents

It has been estimated that 1.3 x 1016 Bq of 239+240 pu has been released to the environment from atmospheric detonation of nuclear weapons that 7.9 x 1014 Bq of 238Pu has been released, mosdy from bum-up of the nuclear powered satellite SNAP-9a and that 3.7 x 1013 Bq of 239+240 Pu was released by the Chernobyl accident (167,168). Many studies have been done to determine the cumulative fallout on soils, plants, bodies of water, animals, and humans. For example, the cumulative 239+240 pu fallout in forest and grasslands and in the liver of eldedy humans in Bavaria, Germany are approximately 50 Bq/m2 and 0.02 Bq/kg wet mass, respectively (167). 

Weapons-grade plutonium, dispersed at military accidents such as Thule in 1968 or as non-fissioned weapon particles after detonation of a Pu-bomb can be characterized by high Pu content relative to the other Pu-isotopes, while accidentally dispersed Pu from the previously widely used nuclear-powered satellites are characterized by high Pu content." The ratio of americium-241 to plutonium isotopes (as " Am is formed by the decay of Pu) is proportional to the initial " Pu concentration, thus it can also be used as an indicator to assess the origin of contamination. However, in most cases, as several sources may contribute to the transuranics content in environmental samples, mixing models applying several isotope ratios are required to assess the origin of possible contamination sources. 

Separation of Plutonium from Air-monitoring Samples. Plutonium-238 2 6 yPu and 21+0Pu have been introduced into environment because of the experiments of nuclear explosion in air and of some accidents of the artificial satellites. Analysis of the plutonium is needed to elucidate the distribution of the plutonium in air and the rate of descent to the surface. For this purpose analytical procedures have been developed and utilized for routine measurements of the air-borne plutonium (18). 

In the analysis of a sarrqrle for its content of natural radioactivity it is necessart today to consider the possibility that the saitqrle has become contaminated by "non-rmtural" radioactivities, i.e. radionuclides added to by human activities (so-called anthropogenic sources). Nuclear weapons tests, nuclear satellites bumt-up in the atmosphere, and nuclear power accidents may release large amounts of activities, see Table 5.4. The nuclear power industry is permitted by health authorities to continually release small, controlled amounts of specified radionuclides into the atmosphere and into open waters. Tables 19.7 and 21.10. 

Nuclear weapons production and testing facilities (Hanford, WA, Savannah River, GA, Rocky Flats, CO, and The Nevada Test Site, in the United States, and Mayak in the former Soviet Union), also released small amounts. The releases occurred in accidents with nuclear weapons, the reentry of satellites that used Pu-238, and by the Chernobyl nuclear reactor accident. 

Accidents with radioactive sources or material include found radioactive material or contaminated areas or items, a lost or missing radioactive source, unshielded source, accidents in a laboratory, transport accidents involving radioactive sources or material, accidents with X-ray machines and particle accelerators, and an accidental reentry of a nuclear-powered satellite, which may lead to impact on the earth s surface and the spread of contamination. Radiological emergencies that could result from deliberate acts, such as terrorist activities... 

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