Source-Term Characterisation and Solid Speciation of Plutonium at the Semipalatinsk Nuclear Test Site, Kazakhstan

In this study, new data on the concentrations of key fission and activation products and transuranium nuclides in samples of soil and water from the former Soviet Union's Semipalatinsk Nuclear Test (Kazakhstan) are presented and interpreted. Our interest in making these measurements was to obtain baseline information on the isotopic signatures of these radionuclides at a number of key (and largely unmonitored) sites within the STS, which could be of use to better interpret measurements elsewhere within the test site and beyond. Sampling took place at Ground Zero (where a total of 116 atmospheric tests were carried out), as well as at the sites of three cratering explosions (Lake Balapan, Tel'kem 1 and Tel'kem 2) and a number of reference locations within the test site boundary but well removed from any localised source. Radionuclide ratios have been used to characterise the source term(s) at each of these sites. The study has been completed by an examination of the geochemical partitioning of plutonium at each of these sites, and an evaluation of the presence and importance of radioactive particles in samples affected by local fallout