One of the main tasks of Chornobyl NPP shutdown stage is shutdown and partial dismantling of individual systems and components of power-generating units. The selected strategy of dismantling described in the Chornobyl NPP Decommissioning Programme specifies a capability at the shutdown stage to dismantle those systems and elements of the installation which are external relative to nuclear reactor and do not affect the safety and are not required for work at the subsequent decommissioning stages. Dismantling approach is from “clean’ equipment to “contaminated” in terms of its radioactivity.
Basic information: ChNPP Decommissioning
The strategy was selected based on the comprehensive analysis of the following factors:
• Ensuring safety of personnel, population and environment
• Availability of infrastructure for managing the dismantled equipment (intermediate storage facilities, stations for decontamination, size-reduction etc.)
• Availability of infrastructure for managing the radioactive waste (final storage facility for waste, facilities and plants for its processing)
• Sufficient funding for decommissioning activities
• Availability of required technologies and accessibility to them
• Prospects for further use of the site for other purposes
The systems and equipment that can be dismantled at the shutdown stage are specified in “The Chornobyl NPP Units 1, 2 and 3 Shutdown Programme”.
In 2008, the Kyiv Institute “Energoproject” completed the feasibility study to determine reasonability and desired time frames of equipment dismantling and processing. This report contains a brief description of fundamental solutions for dismantling of the Turbine Hall equipment, general description of the equipment and elements’ types and volumes to be dismantled, dismantling stages and expected duration, synopsis of operational activity in the course of dismantling and processing stage implementation, impact of implementation time frame on economic, radiological and social indicators.
For ChNPP the optimum option was recommended that foresees the following:
• The most prepared for dismantling equipment includes the systems, components and structures of the Turbine Hall Block “Г” that have been conditioned to the state when they can be dismantled and their radiation parameters enable to carry out the equipment dismantling without working time constraints for personnel;
• Activities with respect to dismantling of the Generation II Block “Г” are to be started immediately as it will lead to reduction of maintenance costs for safety of the building and the equipment inside it as well as due to continuous growth of radioactive waste disposal cost;
• All dismantling activities are to be carried out by contractors as such approach is economically more feasible.
Pursuant to Order of the Ministry of Emergencies of Ukraine dated 14.04.2014 No.382 “On Additional Actions to Implement National Target Environmental Program for Radioactive Waste Management”, the Chornobyl NPP developed an action plan for dismantling, size-reduction and decontamination of radioactively contaminated metal contained within the equipment and steel structures.
On November 14, 2012, a contract for “Dismantling, processing and release from regulatory control of Unit 1 Turbine Hall equipment and structures” was made.
As of now, 10,737 tons of equipment has been dismantled. 207 tons of this equipment have been disposed as RAW; 9,303 tons has been decontaminated and released from regulatory control; 1,164 tons are in the process of decontamination and release from regulatory control.
Basic information: Radioactive Material Management