During October 1-3, 2013, a technical workshop “Results of Activity Related to ChNPP Cooling Pond Decommissioning Options” is taking place in Kiev. The workshop is arranged under performance of IAEA Technical Cooperation Project UKR/9/030 “Assisting ChNPP in Decommissioning and Safe Management of Radioactive Waste”.
The ChNPP Cooling Pond. Photo: www.chnpp.gov.ua
The surveys and pre-design developments carried out during last years to determine a strategy of Cooling Pond (CP) decommissioning showed that implementation of this project will enable not only to reduce capital and operational costs related to control nominal water level in the cooling pond, but also reduce amount of radioactively contaminated waters being generated as a result of continuous water-logging of lower premises of ChNPP Units, mitigate the risks associated with potential failure of protecting dam and reduce carry-over of radioactive substances from CP in Pripyat river due to more filtration of the pond.
However, the negative factors can also appear during Cooling Pond decommissioning, namely, a potential spreading of radioactive aerosols from a surface of drained sections of the pond due to wind raising, effects of uncontrolled development of ecosystem and hydrobionts transformation, which can lead to undesirable ecological and sanitary-hygienic consequences.
Outstanding problems on ChNPP Cooling Pond decommissioning, peculiarities of design documentation development, hydrogeological radiological forecasts, potential ecological changes, measures on remediation and monitoring, and regulatory requirements to the mentioned activity are the issues, which became a topic of discussion at the workshop. The Feasibility Study (FS), being under development by Chernobyl NPP, is also considered during the workshop. The scientists and specialists from SSE “Chernobyl Specialized Industrial Complex”, Institute of Hydrobiology of NASU, Scientific-Research Institute of Agricultural Radiology, Scientific-Research Institute of Radiation Protection of ATSU, Ukrainian Scientific-Research Hydro-Meteorological Institute of NASU, Institute for Mathematical Machines and Systems Problems of NASU, Institute of Geological Sciences of NASU, Institute of Geography of NASU, and IAEA experts participated in the development of separate sections of FS and expert reviews.
The representatives of these organizations, Institute for Safety Problems of NPPs, Ministry of Ecology and Natural Resources, Ministry of Health, State Nuclear Regulatory Inspectorate, State Agency for Exclusion Zone Management, and “UkrGosStroyEkspertiza” joined to participate in the workshop and discuss pointed issues.
Involvement of experienced specialists at FS review stage will enable to ensure safe decommissioning of ChNPP Cooling Pond and create the conditions for natural self-regeneration of ecosystem transformed within its territory.
The ChNPP Cooling Pond (CP) was built by means of creating an artificial protecting dam on a flood-plain territory of Pripyat of about 22.9 km2 area. The volume of CP water is expected to cool 4 Units of ChNPP in electric power generation mode. The losses from filtration and evaporation of the pond water are replaced from Pripyat using delivery pumps to a design level 111.00 mB that is higher than level in Pripyat river for 7 meters.
As a result of beyond design basis accident at ChNPP in 1986, the radioactive aerosols have deposited on CP surface, as well as dispersed fuel particles from destroyed reactor. Moreover, about 5,000 m3 of contaminated water have been discharged from the plant’s engineering systems. A part of water was delivered therein used for fire-fighting at Unit 4 during an accident, as well as, partially, the waters collected in a storm water drainage system following ChNPP site decontamination.
The ChNPP shutdown in power-generating mode enabled to decommission most of the systems, for functioning of which process water supply was needed. Nowadays, the amount of water in ChNPP Cooling Pond became exceeding its requirements many times. Herewith, the annual costs for maintaining the Cooling Pond dam in safe condition and operation of the pump station constitute about UAH 5 million.