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Perianez R.,University of Seville | Bezhenar R.,Ukrainian Center of Environmental and Water Projects | Iosjpe M.,Norwegian Radiation Protection Authority | Maderich V.,Institute of Mathematical Machine and System Problems | And 4 more authors.
Journal of Environmental Radioactivity | Year: 2015

Four radionuclide dispersion models have been applied to simulate the transport and distribution of 137Cs fallout from Chernobyl accident in the Baltic Sea. Models correspond to two categories: box models and hydrodynamic models which solve water circulation and then an advection/diffusion equation. In all cases, interactions of dissolved radionuclides with suspended matter and bed sediments are included. Model results have been compared with extensive field data obtained from HELCOM database. Inventories in the water column and seabed, as well as 137Cs concentrations along 5 years in water and sediments of several sub-basins of the Baltic, have been used for model comparisons. Values predicted by the models for the target magnitudes are very similar and close to experimental values. Results suggest that some processes are not very relevant for radionuclide transport within the Baltic Sea, for instance the roles of the ice cover and, surprisingly, water stratification. Also, results confirm previous findings concerning multi-model applications. © 2014 Elsevier Ltd. Source


Heling R.,Nuclear Research and Consultancy Group | Bezhenar R.,Ukrainian Center of Environmental and Water Projects
Radioprotection | Year: 2011

The uptake of radioceasium and radiostrontium in biota in dose assessment models is mostly estimated on the basis of Concentration Factors (CF). For accidental releases, the dynamical foodweb model BURN has been implemented in the coastal model POSEIDON (part of the Decision Support System RODOS). BURN can be applied on water bodies with different salinity levels, since in the model the uptake of radioceasium and radiostrontium in phytoplankton is governed by potassium and calcium in the water, which are calculated via the easier-to-obtain parameter salinity. Recently a dataset on radiocaesium and radiostrontium has been collected for various aquatic organisms in the Dnieper-Bug Estuary (DBE) in Ukraine, which enabled model validation with BURN. Considering the limitation of compartment models and the fact BURN is a predictive model, with fixed model parameters, the model results are within a reasonable range with the measurement data. Besides comparison with measurement data, the model calculations were also used to derive values for CF and compared with literature, which gave reasonable results for Cs-137 in fish and molluscs. For Sr-90 however, the calculated values exceeded the levels given in literature, since equilibrium between radionuclides in biota and water is not reached. Longer time periods for the radionuclide flux into the DBE, both from the Dnieper and the Black Sea are required to obtain high quality model results for the years after 1989. © 2011 EDP Sciences. Source


Maderich V.,Institute of Mathematical Machine and System Problems | Bezhenar R.,Ukrainian Center of Environmental and Water Projects | Heling R.,Nuclear Research and Consultancy Group | de With G.,Nuclear Research and Consultancy Group | And 5 more authors.
Journal of Environmental Radioactivity | Year: 2014

The compartment model POSEIDON-R was modified and applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of radioactivity in the period 1945-2010, and to perform a radiological assessment on the releases of radioactivity due to the Fukushima Dai-ichi accident for the period 2011-2040. The model predicts the dispersion of radioactivity in the water column and in sediments, the transfer of radionuclides throughout the marine food web, and subsequent doses to humans due to the consumption of marine products. A generic predictive dynamic food-chain model is used instead of the biological concentration factor (BCF) approach. The radionuclide uptake model for fish has as a central feature the accumulation of radionuclides in the target tissue. The three layer structure of the water column makes it possible to describe the vertical structure of radioactivity in deep waters. In total 175 compartments cover the Northwestern Pacific, the East China and Yellow Seas and the East/Japan Sea. The model was validated from 137Cs data for the period 1945-2010. Calculated concentrations of 137Cs in water, bottom sediments and marine organisms in the coastal compartment, before and after the accident, are in close agreement with measurements from the Japanese agencies. The agreement for water is achieved when an additional continuous flux of 3.6TBqy-1 is used for underground leakage of contaminated water from the Fukushima Dai-ichi NPP, during the three years following the accident. The dynamic food web model predicts that due to the delay of the transfer throughout the food web, the concentration of 137Cs for piscivorous fishes returns to background level only in 2016. For the year 2011, the calculated individual dose rate for Fukushima Prefecture due to consumption of fishery products is 3.6μSvy-1. Following the Fukushima Dai-ichi accident the collective dose due to ingestion of marine products for Japan increased in 2011 by a factor of 6 in comparison with 2010. © 2013 Elsevier Ltd. Source


Kovalets I.V.,Institute of Mathematical Machines and Systems Problems NAS of Ukraine | Kovalets I.V.,Ukrainian Center of Environmental and Water Projects | Kivva S.L.,Institute of Mathematical Machines and Systems Problems NAS of Ukraine | Udovenko O.I.,Institute of Mathematical Machines and Systems Problems NAS of Ukraine
Natural Hazards | Year: 2015

The mesoscale meteorological/distributed hydrological model chain WRF/DHSVM was calibrated for simulation of extreme flood events in Uzh River basin in Ukrainian Carpathians. The flood event which happened in July 2008 was successfully reproduced by using final analysis meteorological input data of the US National Centers for Environmental Prediction (NCEP). For climate run for the period of 1960–1990, the NCEP Reanalysis-1 meteorological data were used. Frequencies of extreme precipitation events obtained by fitting of the measured and simulated precipitation time series with the generalized extreme value distribution were very close. Simulated water discharges for the very extreme floods happening from once per 50 to once per 100 years were in good agreement with the water discharges of the same frequencies obtained by statistical processing of measurements. © 2014, Springer Science+Business Media Dordrecht. Source


Grant
Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: Fission-2010-3.3.1 | Award Amount: 2.72M | Year: 2011

This project aims on the one hand to keep the momentum gained through the European Project EURANOS in establishing a platform where the operational and research community can meet and discuss with all the relevant stakeholders the topics related to emergency response and recovery preparedness and on the other hand to tackle urgent research topics in the area of nuclear emergency response and recovery preparedness. It addresses the call Fission-2010-3.3.1: European platform on emergency and post-accident preparedness and management. Through a collaboration of industry, research and governmental organisations in Europe, methodological aspects and computational models will be developed to be consistent with recent recommendations from international bodies such as the ICRP (International Commission of Radiation Protection) and improve Europes response by coupling the decision support systems with an early notification system such as ECURIE. Within this project, a platform will be established that will be a unique place for combined meeting of the research and the operational community.

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