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Decommissioning of the Ignalina Nuclear Power Plant involves multiple problems. One of them is personnel radiation safety during the performance of dismantling activities. In this paper, modeling results of radiation doses during the dismantling of the pressurized tank from the emergency core cooling system (ECCS PT) of RBMK-1500 reactor are presented. The radiological surveys indicate that the inner surface of the ECCS PT is contaminated with radioactive products of corrosion and sediments due to the radioactive water. The effective doses to the workers have been modeled for different strategies of ECCS PT dismantling. In order to select the optimal personnel radiation safety, the modeling has been performed by the means of computer code “VISIPLAN 3D ALARA Planning tool” developed by SCK CEN (Belgium). The impacts of dismantling tools, shielding types, and extract ventilation flow rate on effective doses during the dismantling of ECCS PT have been analyzed. The total effective personnel doses have been obtained by summarizing the effective personnel doses from various sources of exposure, that is, direct radiation from radioactive equipment, internal radiation due to inhalation of radioactive aerosols, and direct radiation from radioactive aerosols arising during hot cutting in premises. The uncertainty of the collective doses is also presented in this paper.

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Decommissioning of the Ignalina Nuclear Power Plant involves multiple problems. Personnel radiation safety during the dismantling activities is one of them. In order to assess the optimal personnel radiation safety, the modelling is performed by means of computer code "VISIPLAN 3D ALARA Planning tool" developed by SCK CEN (Belgium). In this paper it was used for the evaluation of direct gamma radiation from the radioactive equipment to personnel when carrying out dismantling activities and selection of gamma radiation shielding geometry (structure), shielding materials and positions. A modelling of radiation doses during the dismantling of the maintenance cooling reservoir (MCR) of RBMK-1500 reactor has been performed in this paper. The basic MCR model's development was based on internal contamination and the existing geometrical data. The assessment of workers exposure was performed to comply with ALARA. The effective doses to the workers were calculated for different strategies of reservoir dismantling. The impacts of dismantling tools, shielding types, variation of parameters such as shielding distance, shielding installation time and exhaust ventilation flow rate during the dismantling of reservoir on effective doses were analyzed. The total effective personnel doses were obtained by summarizing the effective personnel doses from various sources of exposure, i.e., direct radiation from radioactive equipment, internal radiation due to inhalation of radioactive aerosols, and direct radiation from radioactive aerosols arising during hot cutting in premises.