Radionuclide migration in the experimental polygon of the Red Forest waste site in the Chernobyl zone – Part 1: Characterization of the waste trench, fuel particle transformation processes in soils, biogenic fluxes and effects on biota

A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction of released refractory radionuclides such as uranium (U) and plutonium (Pu) were present as entities ranging from sub microns to fragments. Furthermore, radioactive particles and colloids have been released from reprocessing facilities and civil reactors, from radioactive waste dumped at sea, and from NORM sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics such as particle size distribution, structure, and oxidation state influencing ecosystem transfer depend also on the release scenarios. When radioactive particles are deposited in the environment, weathering processes occur and associated radionuclides are subsequently mobilized, changing the apparent K. Thus, particles retained in soils or sediments are unevenly distributed, and dissolution of radionuclides from particles may be partial. For areas affected by particle contamination, the inventories can therefore be underestimated, and impact and risk assessments may suffer from unacceptable large uncertainties if radioactive particles are ignored. To integrate radioactive particles into environmental impact assessments, key challenges include the linking of particle characteristics to specific sources, to ecosystem transfer, and to uptake and retention in biological systems. To elucidate these issues, the EC-funded COMET and RATE projects and the IAEA Coordinated Research Program on particles have revisited selected contaminated sites and archive samples. This COMET position paper summarizes new knowledge on key sources that have contributed to particle releases, including particle characteristics based on advanced techniques, with emphasis on particle weathering processes as well as on heterogeneities in biological samples to evaluate potential uptake and retention of radioactive particles.

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“…Cooling Pond bottom sediments can be described as a sum of first-order kinetic equations (Kashparov et al, 2012):…”

Section: Linking Particle Characteristics To Ecosystem Transfermentioning

confidence: 99%

Challenges associated with the behaviour of radioactive particles in the environment

Salbu

Kashparov

Lind

et al. 2018

Journal of Environmental Radioactivity

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“…Pu was mainly released in form of fuel particles as it was associated with the uranium fuel that was emitted from the reactor core. It got deposited in the surrounding soil, mainly contaminating the 30-km zone around the accidental reactor [ 14 , 15 ]. The deposited fuel particles varied, according to the scenarios during the accident, in their chemical compositions, morphologies and oxidation states [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved analysis of plutonium isotopic signatures in environmental particle samples by laser ablation-MC-ICP-MS

Konegger-Kappel

Prohaska

2015

Anal Bioanal Chem

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Laser ablation–multi-collector–inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) was optimized and investigated with respect to its performance for determining spatially resolved Pu isotopic signatures within radioactive fuel particle clusters. Fuel particles had been emitted from the Chernobyl nuclear power plant (ChNPP) where the 1986 accident occurred and were deposited in the surrounding soil, where weathering processes caused their transformation into radioactive clusters, so-called micro-samples. The size of the investigated micro-samples, which showed surface alpha activities below 40 mBq, ranged from about 200 to 1000 μm. Direct single static point ablations allowed to identify variations of Pu isotopic signatures not only between distinct fuel particle clusters but also within individual clusters. The resolution was limited to 100 to 120 μm as a result of the applied laser ablation spot sizes and the resolving power of the nuclear track radiography methodology that was applied for particle pre-selection. The determined 242Pu/239Pu and 240Pu/239Pu isotope ratios showed a variation from low to high Pu isotope ratios, ranging from 0.007(2) to 0.047(8) for 242Pu/239Pu and from 0.183(13) to 0.577(40) for 240Pu/239Pu. In contrast to other studies, the applied methodology allowed for the first time to display the Pu isotopic distribution in the Chernobyl fallout, which reflects the differences in the spent fuel composition over the reactor core. The measured Pu isotopic signatures are in good agreement with the expected Pu isotopic composition distribution that is typical for a RBMK-1000 reactor, indicating that the analyzed samples are originating from the ill-fated Chernobyl reactor. The average Pu isotope ratios [240Pu/239Pu = 0.388(86), 242Pu/239Pu = 0.028(11)] that were calculated from all investigated samples (n = 48) correspond well to previously published results of Pu analyses in contaminated samples from the vicinity of the Chernobyl NPP [e.g. 240Pu/239Pu = 0.394(2) and 242Pu/239Pu = 0.027(1); Nunnemann et al. (J Alloys Compd 271–273:45–48, 1998)].Graphical AbstractEvaluation of LA-MC-ICP-MS for spatially resolving ultra-trace Pu isotopic signatures stored in environmental radioactive particles, providing new insights into the Pu isotopic distribution of the Chernobyl reactor core at the time of the accident

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“…As a rule, the main sources of pollution are concentrated in the so-called bury repositories, which contain radioactive waste buried in the ground. When water passes through these structures, pollutants enter the groundwater [10][11][12]. The study of information sources confirmed that digging up and transporting this waste can be dangerous [13].…”

Section: Analysis Of Information Sourcesmentioning

confidence: 92%

“…The drilling rig (3) draws the injector (7) in the well (6) according to the project trajectory, wherein the swivel (11) rotates with the drill rod (9) not transmitting rotational movement to the injector (7). The injection mortar is fed from the supply line (12) to the injector (7), which is drawn in by the traction device (13) (Figure 3). The distance between the wells is assigned depending on the mortar distribution radius, and should not exceed two radii of the distribution zone ( Figure 4).…”

Section: Concept Of the Proposed Technologymentioning

confidence: 99%

Innovative Technology of Horizontal Protective Shield Arrangement Using Injection

Meneylyuk

Petrovskiy

Borisov

et al. 2017

e-GFOS

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Radionuclide migration in the experimental polygon of the Red Forest waste site in the Chernobyl zone – Part 1: Characterization of the waste trench, fuel particle transformation processes in soils, biogenic fluxes and effects on biota

Cited by 48 publications

References 13 publications

Challenges associated with the behaviour of radioactive particles in the environment

Challenges associated with the behaviour of radioactive particles in the environment

Spatially resolved analysis of plutonium isotopic signatures in environmental particle samples by laser ablation-MC-ICP-MS

Innovative Technology of Horizontal Protective Shield Arrangement Using Injection

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