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RESEARCH OF SPECIES OF ARTIFICIAL RADIONUCLIDES 137Cs, 90Sr,
239+240Pu и 241Am IN SOILS OF CONDITIONALLY «BACKGROUND »
TERRITORIES OF SEMIPALATINSK TEST SITE
Kunduzbaeva А.Е., Lukashenko S.N., Kabdyrakova А.М., Bakirova G.А.
Institute of Radiation Safety and Ecology of National Nuclear Center of the Republic of
Kazakhstan, Kurchatov city, Kazakhstan
The work provides results of research of species of artificial radionuclides in soils
of conditionally «background» territories of the STS. These territories include
«northern», «western», «southeastern» and «southern» parts of the STS, specified in this
way according to their geographic location at the test site territory. In spite being closely
located to testing spots, radiological situation at the most of conditionally «background»
territories mainly depends on global fallouts, except for zones of «plumes» from local
fallouts of surface nuclear tests, conducted at the «Experimental Field». «Plumes» of
fallouts, crossing «southeastern» and «southern» parts of the STS, could determine
another character of radioactive contamination of the soil cover.
As a result of performed researches low mobility of 137Cs and 239+240Pu was found
in soils notwithstanding type of fallouts, conditioned radioactive contamination of soils.
The main concentration of 241Am transuranium radionuclide in soils was found in
tightly bound form, that is not accessible for plants, less significant concentration was
noticed in mobile (acid-soluble) form, representing potential reserve for plants. As it
was noted, 90Sr radionuclide is the most soluble in soils Along with tightly bound forms
of 90Sr, presence of easily accessible forms (exchangeable form) and forms representing
potential reserve for plants (mobile form) was also found in soil. Herewith, the ratio
between exchangeable and non- exchangeable forms of radionuclide is different, both
for background sites and for the zones with increased radiation background. So the
result of investigation of 90Sr radionuclide mobility can be used as an additional
parameter when studying the character of radioactive contamination of soil cover and
when determining the impact of fallouts from surface nuclear tests on the territories
under research.