ANALYSIS OF EFFICIENCY OF REHABILITATION OF THE RADIUM PRODUCTION WASTE STORAGE TERRITORY IN THE KOMI REPUBLIC

L.M. Shaposhnikova, N.G. Rachkova

Institute of Biology, Komi Scientific Center, Ural Branch, Russian Academy of Science, Kommunisticheskaya ul. 28, Syktyvkar, 167982 Russia

E-mail: shaposhnikova.l.m@ib.komisc.ru, rachkova@ib.komisc.ru

Based on the data on long-term dynamics of radiation background, contents and forms of radium-226 in water and soils, the effectiveness of rehabilitation of the radioactive waste storage site of radium produc-tion in the Komi Republic was estimated. The object with an area of 40 thousand square meters is rep-resented by a site of floodplain-terrace type, located about 20 meters far from the Ukhta River. Reha-bilitation of storage area was carried out twice: in 1962 by applying a sand-gravel mixture to its surface (earthfill method) and in 2014–2015 by the method of conservation of radioactive waste with the con-struction of geochemical and physical barriers to prevent the migration of pollutants into environment. It was found that the earthfill method reduced maximum radiation background on the waste storage area from 120–250 to 70 µSv/h. However, it did not prevent the inclusion of radium to soil formation process-es and biogenic cycles of migration. It also did not exclude the receipt of pollutant into the hydrographic network and the redistribution of radionuclide stock into the subordinate elements of the landscape with the formation of secondary foci of contamination. This was also facilitated by the landscape-geochem-ical features of the waste storage site and the increased solubility of radium compounds in mineralized near-surface natural solutions.

All these shortcomings were taken into account in 2014–2015 while carrying out the conservation of rad-waste, which should ensure long-term and multi-stage safety of the facility. Presently radium specific ac-tivity in the groundwater of the coastal strip near the conservation site has decreased by more than 10 times. Specific electrical conductivity decreased from 3 200 to 2 200 µS/cm. In the annual cycle, water quality corresponded to the sanitary and hygienic standards, but as before it was characterized by a high-er mineralization relative to background. Water from a well of radiant drainage, poured into the river, does not possess biotoxicity. In 2016, maximum radium content in the river waters refers to the sections of the riverbed near the drains from unrehabilitated areas of former production facilities, which also in-dicates the effectiveness of rehabilitation at this stage and reduction of the hazard of the object.

Key words: radioactive contamination, radioactive waste, radium-226, dynamics, aquatic migration, conservation of radioactive waste, rehabilitation.

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