RECONSTRUCTION OF THE TECHA RIVER CONTAMINATION AS A
RESULT OF RADIOACTIVE RELEASES FROM THE “MAYAK”
PRODUCTION ASSOCIATION IN 1949-1956
1
MO Degteva , NB Shagina1, MI Vorobiova1, LR Anspaugh2 and BA Napier3
1
Urals Research Center for Radiation Medicine, Chelyabinsk, 454076 Russia
2
University of Utah, Salt Lake City, Utah, USA
3
Pacific Northwest National Laboratory, Richland, Washington, USA
The Mayak Production Association (MPA) was the first site for the production of
weapon-grade plutonium in Russia. Early operations led to routine and accidental
waterborne release of large amounts of radioactive materials into the small Techa River.
The major releases occurred during 1950–1951. The releases and subsequent flooding
resulted in the deposition of sediments along the shoreline and on floodplain soil.
Pioneer studies of the processes of the distribution of uranium fission products in
biomass and non-living components of water bodies were started under supervision of
Nikolay Timofeeff-Ressovsky in the so-called “laboratory B” established at 40 km from
the MPA. Initial aim of the study was physical modeling of radionuclide behavior in
flowing and stagnant reservoirs in order to clarify the situation of the contaminated
Techa River and its lakes.
More accurate reconstruction of the radioactive
contamination of the Techa River system has been made recently on the basis of refined
data on the amounts and the rate of discharge of radionuclides from the MPA. This
improved understanding is possible because of access to many archive documents that
have been declassified and become available. An improved Techa River model has
been developed that describes transport of radionuclides through the up-river ponds and
along free-flowing river as well as deposition of radionuclides in bottom sediments and
flooded areas. The model considers transport of radionuclides adsorbed on solid
particles and in soluble form. The output of the model provides concentrations of all
source-term radionuclides in the river water, bottom sediments and floodplain soils at
different distances from the site of radioactive releases. The outputs of the model show
good agreement with historical measurements of water and soil contamination. The
model will be used for reconstruction of internal and external doses received by
residents of the Techa riverside communities.