Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine

Kiev, Ukraine

Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine

Kiev, Ukraine
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Kashparov V.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Yoschenko V.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Levchuk S.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Bugai D.,Ukrainian Academy of Sciences | And 3 more authors.
Applied Geochemistry | Year: 2012

This review article introduces an experimental site located within the Chernobyl exclusion zone that is equipped to study radionuclide behavior in the environment after disposal of radioactive waste into shallow subsurface storage (trenches). This paper presents how the site is equipped and the methodology that was followed in order to understand and reproduce the observed 90Sr contaminant plume downstream from a shallow waste trench in an area about 2.5km west of the Chernobyl Nuclear Power Plant (ChNPP), called the Red Forest. The main results include identification of the radionuclide source term (the distribution and inventories of radionuclides in the trench, the description of the physical and chemical properties of the fuel particles encountered in the waste trench) and a model of fuel particle dissolution and subsequent radionuclide leaching into the soil solution. The biogenic migration of radionuclides from the trench to, and effects of radiation on, plants (Scots pine) are also described. © 2011 Elsevier Ltd.


Bugai D.,Institute of Geological science | Skalskyy A.,Institute of Geological science | Dzhepo S.,Institute of Geological science | Kubko Y.,Institute of Geological science | And 5 more authors.
Applied Geochemistry | Year: 2012

This article represents the second of two articles, which review the main results of the international radioecological projects: Chernobyl Pilot Site Project (1999-2003) and Experimental Platform in Chernobyl (2004-2008). These projects studied radionuclide migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues: geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986-2002). The models involved the following sub-models: (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW - MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to K ds and dispersivities allowed quite accurate reproduction of 90Sr migration behavior for the early period (1995-1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999-2002) suggests the need to improve the conceptual radionuclide migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site). © 2011 Elsevier Ltd.


Levchuk S.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Kashparov V.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Maloshtan I.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Yoschenko V.,Ukrainian Institute of Agricultural Radiology UIAR NUBiP of Ukraine | Van Meir N.,Institute for Radiological Protection and Nuclear Safety
Applied Geochemistry | Year: 2012

Field experiments and laboratory studies were performed to investigate migration processes of plutonium isotopes from a near-surface radioactive waste trench to the underlying sandy aquifer at the Red Forest waste dump in the Chernobyl zone. The objectives of these experiments were to characterize the spatial distribution and possible migration mechanisms of plutonium in the aquifer. During 2002-2007 experimental investigations were carried out and spatial distributions of plutonium isotopes ( 239,240Pu, 238Pu), 90Sr and major ions in the aquifer in the direction of the groundwater flow were obtained. Specific activities of radionuclides in groundwater depended on the location of the piezometer and varied in the range of 1-360mBqkg -1 for 239,240Pu, 0.5-180mBqkg -1 for 238Pu and n-n·10 4 Bqkg -1 for 90Sr. It was found that the spatial features of the distributions of plutonium and strontium specific activities in the upper eolian aquifer were similar, i.e. there was a correlation between the positions of the activity maxima of the radionuclides. The Pu isotopes plume in the aquifer spreads about 15m downstream of the radionuclides source. Characterization of the initial radionuclide composition of the waste showed that all plutonium in the aquifer originated from the trench. The ratio of plutonium isotopes ( 239,240Pu/ 238Pu) at the sampling time was the same in waste material and in groundwater samples. In situ ultrafiltration of several groundwater samples was carried out. The size fractionation data obtained suggest that a significant part of plutonium (50-98%) in the groundwater sampled close to the source from the upper part of the aquifer is associated with a very low molecular weight fraction (<1kDa). © 2012 Elsevier Ltd.

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