3-D numerical modelling of mud and radionuclide transport in the Chernobyl Cooling Pond and Dnieper - Boog Estuary

Margvelashvili, Nugzar; Maderich, Vladіmir; Yuschenko, S.; Zheleznyak, Mark

doi:10.1016/s1568-2692(02)80042-0

Cited by 10 publications

(9 citation statements)

References 11 publications

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“…The exchange processes between water and solids in most models are described in the frame of a one-step reversible reaction of sorption/ desorption on the surface of particles (e.g. [18,26,27]); however, the mobility of radionuclides can be affected by a slow sorption process which ''fixes'' the ion to the solids due to the penetration of ions into the structure of sediment particles and interlattice spacing [20,22,33,35]. These processes were taken into account using two-step fast and slow reversible reactions [9,20,25,36].…”

Section: Introductionmentioning

confidence: 99%

Migration of radioactivity in multi-fraction sediments

et al. 2017

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A new 3D radioactivity transport model coupled with multiscale circulation and multi-fractional sediment transport modules is presented. The sediment transport module simulates the transport of a mixture of one cohesive sediment fraction and a number of fractions of non-cohesive sediments of different sizes and densities. The model of radionuclide transport describes the key transport and exchange processes in the system of water-suspended and bottom multi-fraction sediments. Two-step kinetics with two successive reversible fast and slow reactions is used in the model. A noticeable feature of the model is approximation of the sediment and contamination profiles in the bed by multiple well-mixed layers to describe the vertical migration of radioactivity within bottom sediments due to erosion/deposition, molecular diffusion and bioturbation. The model accurately reproduced a laboratory experiment on the uptake of radiocesium by lake sediments. An analytical solution describing mutual adjustment of the concentrations of radioactivity in the pore water and in the multi-fraction sediment showed that activity was redistributed between different fractions of sediments far slower than between water and the total concentration in the sediment. The extended one-layer model of bottom contamination of multi-fraction sediments was derived from a general model and compared with a multilayer model. It was found, however, that the one-layer approximation was not capable of correctly predicting the inventory due to the fact that one-layer averaged concentration can essentially differ from the near-surface value in the multi-layer model. Radionuclide 123Environ Fluid Mech (2017) 17:1207-1231 DOI 10.1007 transport in channel with bottom depression was simulated to estimate the effects of erosion/deposition and the multi-fractionality of sediments on the transport process. It was shown that these factors affect the distribution of sediments by forming local maxima and minima of activity at the beginning and end of the depression, respectively, due to the redistribution of contaminated bottom sediments by flow. The developed model can also be used to simulate the transport of a wide class of toxic substances sorbed on sediments.

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Section: Introductionmentioning

confidence: 99%

Migration of radioactivity in multi-fraction sediments

et al. 2017

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“…In 2002, RODOS （Real-time On-line Decision Support）which developed by European Commission has added THREETOX 3-D hydraulic model which includes sediment transportation and radionuclide transportation. In the paper [6,7], Margvelashvily has rebuilt the dispersion of Cs-137 and Sr-90 diffusion in the estuaries and shelf seas.After FUKUSHIMA nuclear accidents, researches of Daisuke Tsumune simulate the distribution of Cs-137 in the sea by Regional Ocean Modeling system [8].…”

Section: Research Developmentsmentioning

confidence: 99%

Study on Transferring and Diffusing of the radioactive nuclidesafter Coastal Nuclear Power Plant Accidentin Coastal Seawater

Shaowei¹,

Hou²,

Chen³

et al. 2012

Proceedings of the 1st International Conference on Mechanical Engineering and Material Science

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Abstract-A large amount of radioactive substances have been discharged into the sea during the Fukushima nuclear accident, which did tremendous harm to the marine ecological environment. The progress in study of relocation diffusion and transformation of radionuclide in water from coastal nuclear power plant accident are reviewed in this paper. The factors influencing the diffusion and transformationof radionuclide are discussed and analyzed from discharge source item, characteristic of coastal environment, simulation of radionuclide relocation diffusion. Based on the existing studies and researches, the characteristic of coastal environment and the reactor type of a coastal nuclear power plant in China, a computer systemsimulating the transferring and diffusing of the radioactive nuclides after accident in coastal seawater was designed and developed. The main models of system were introduced, including fluid dynamics model, transportation of sediments model and nuclide transportation model. Keywords-coastal nuclear power; accident condition; transferring of the radioactive nuclides;diffusing of the radioactive nuclides

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“…This section will present the modifications made to include the computation of suspended sediment in POM. The governing equation for suspended sediment transport in sigma coordinate is: (1) where C is the concentration of the suspended sedimentary material, U, V and w are current velocities in x, y and a direction respectively, ws is settling velocity (downward direction) of the considered sediment type; H is the bottom depth; D is total depth; and Kx, Ky, KH are diffusion coefficients. Here we set Kx=Ky=Ah, where Ah is horizontal eddy diffusivity used in POM.…”

Section: The Model Systemmentioning

confidence: 99%