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Radioactive waste management is an important component of the Chernobyl Nuclear Power Plant accident mitigation and remediation activities of the so-called Chernobyl ExclusionZone. This article describes the localization and characteristics of the radioactive waste present in the Chernobyl Exclusion Zone and summarizes the pathways and strategy for handling the radioactive waste related problems in Ukraine and the Chernobyl Exclusion Zone, and in particular, the pathways and strategies stipulated by the National Radioactive Waste Management Program.

Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90 Sr and 137 Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

The Chernobyl accident resulted in the contamination of the environment with long-lived radionuclides, including transuranium elements. The results, more accurate than the data of [1], for the production of the basic long-lived radionuclides in the reactor core where the accident occurred [2] are presented in Table 1.According to Table 1, the 241pu contribution to the total activity of transuranium elements accumulated in the reactor core is about 84%. Since the same amounts escaped into the atmosphere during the accident (3% [1]), this remark is also valid with respect to the radioactive contamination of the environment.The contamination of the environment by 24tAm is due both to its direct emission from the reactor core and the subsequent accumulation as a result of B-decay of 241Pu.The time dependence of the accumulation of 241Am activity in the environment is described by the equationwhere Aot and A02 are, respectively, the 24tpu and 24tAm emissions during the accident (in PBq); X t = 0.0482 yr -t is the decay constant of 241pu; X 2 = 0.0016 yr -I is the decay constant of 241Am; and, t is the time after the accident (in yr).We now introduce the function Y(t), which is the ratio of the 241Am activity at time t to the activity of the material emitted during the accident, i.e., Y(t) = A2(t)/A02.From Eq.(1) we obtain the expressionwhere k = X2/(X l -X2)(AoJA02 ).It is easy to show that the maximum of the function Y(t)

Decommissioning of nuclear power plants and other nuclear fuel cycle facilities has been an imperative issue lately. There exist significant experience and generally accepted recommendations on remediation of lands with residual radioactive contamination; however, there are hardly any such recommendations on remediation of cooling ponds that, in most cases, are fairly large water reservoirs. The literature only describes remediation of minor reservoirs containing radioactive silt (a complete closure followed by preservation) or small water reservoirs resulting in reestablishing natural water flows. Problems associated with remediation of river reservoirs resulting in flooding of vast agricultural areas also have been described. In addition, the severity of environmental and economic problems related to the remedial activities is shown to exceed any potential benefits of these activities. One of the large, highly contaminated water reservoirs that require either remediation or closure is Karachay Lake near the MAYAK Production Association in the Chelyabinsk Region of Russia where liquid radioactive waste had been deep well injected for a long period of time. Backfilling of Karachay Lake is currently in progress. It should be noted that secondary environmental problems associated with its closure are considered to be of less importance since sustaining Karachay Lake would have presented a much higher radiological risk. Another well-known highly contaminated water reservoir is the Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond, decommissioning of which is planned for the near future. This study summarizes the environmental problems associated with the ChNPP Cooling Pond decommissioning.