Radionuclides accidental releases

Investigate accidents which may have led to persons receiving effective doses in excess of 6 mSv or an equivalent dose greater than 30% of any relevant dose limit. Investigate and report to the authorities loss of materials from accidental release to atmosphere, spillages, theft. The Regulations provide a comprehensive list of notifiable concentrations for each radionuclide isotope. 

The determination of radionuclides in environmental samples is an important task in relation to the protection of human health. This is especially the case when there is an accidental release of radioactivity into the environment, as was the case with the Chernobyl accident. Assessment of the situation requires knowledge of the type and form of released radionuclides and reliable, practical techniques for the analysis of various radionuclides. 

Actinides in the environment can be classified into two groups (i) the uranium and thorium series of radionuclides in the natural environment and (ii) neptunium, plutonium, americium and curium which are formed in a nuclear reactor during the neutron bombardment of uranium through a series of neutron capture and radioactive decay reactions. Transuranics thus produced have been spread widely in the atmosphere, geosphere and aquatic environment on the earth, as a result of nuclear bomb tests in the atmosphere, and accidental release from nuclear facilities (Sakanoue, 1987). Most of these radionuclide inventories have deposited in the northern hemisphere following the tests conducted by the United States and the Soviet Union. 

In this chapter we will address the problem of accidental release of radionuclides into the environment. Accidental release could be the consequence of the following activities ... 

Many other radionuclides would be present in debris from a nuclear accident, and their potential contribution to human exposure depends on the type of accident and the circumstances when it occurred. Since there are several types of fuel, the spectra of radionuclides that would be present in accidental releases could be somewhat different. 

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