At the site of the Federal State Unitary Enterprise Radon’s Saida Bay branch in Murmansk region, disposal is underway of the first of three used steam generators that were part of the VVER-1000 reactor units at the Balakovo NPP. Radon is part of Rosatom’s Environmental Division.
During the recycling process, non-radioactive metal will be sent for recycling like regular scrap metal. It is expected that more than 60% of all metal will be recyclable initially. In the future, the volume of metal returned for re-use may increase to 90%. Vasily Tinin, Director for State Policy in the Field of Radioactive Waste, Spent Nuclear Fuel and Decommissioning of Radiation Hazardous Facilities) at Rosatom noted that this was the first ever recycling of a major NPP component.
Balakovo NPP comprises four VVER-1000 reactor units which began operation in 1985, 1987,1988 and 1993. The steam generators for units 1&3 were replaced in 1998. The four used steam generators – each weighing 322 tonnes – have been kept in a special storage facility on site for more than 30 years. Immediately after their removal, they were chemically washed inside and decontaminated outside. Lead shot was poured into the connectors of the primary circuit to act as a biological protection. All connectors were plugged and welded, after which a protective paint and varnish coating was applied.
In July, the first of the four used steam generators was removed from the storage facility and prepared it to be transported for dismantling and disposal. The participants in the pilot project used PGV-1000 M steam generators were specialists from Balakovo NPP, OKB Spetstyazhproekt and the Balakovo branch of JSC Atomenergoremont (Rosatom’s Electric Power Division).
“Rosatom carried out a uniquely complex transportation of steam generators to the site in Saida Bay, said tinin. “A number of innovative technologies will be used when disposing of the units. Moreover, the entire range of work is being carried out using existing infrastructure. Until now, only the reactor compartments of nuclear submarines and icebreakers were prepared for destruction in Saida Bay. Expanding the functionality of the existing site will allow it to be used more efficiently, avoiding the costs of new construction – especially for NPP equipment.”
He added: “In general, the project will help the state corporation develop technologies and gain reference experience in the safe disposal of large equipment at nuclear power plants. In the context of the upcoming serial decommissioning of nuclear power units that have exhausted their resources, this competence and the capacity for its implementation will be in demand in the coming years.”
Radon General Director Alexey Luzhetsky, said: “We understand that the pace of our work and the load on our employees and production will only increase. Therefore, to further increase safety and optimise processes, we are introducing robotic systems and digital systems at Radon enterprises. An increase in work volumes potentially means an increase in the amount of waste for disposal. To avoid this, we are now discussing the possibility of building a metallurgical complex on the territory of our enterprise in the Murmansk region. As the successful world and Russian experience in decontaminating metals by remelting shows, high-temperature processing will allow up to 90% of metal waste to be quickly and safely returned to economic circulation.”
Before transportation to the disposal site, the spent steam generators underwent a thorough radiation examination and sealing and were prepared for safe transportation by road and water transport. Disposal will take place in several stages. Initially, the case made of special steel will be opened. Both traditional technologies and innovative solutions will be used (in particular, a pilot use of remote laser cutting is planned). At the second stage, the internal elements through which the coolant circulated will be removed from the steam generator housing. They will be packaged in special containers and placed on site for temporary storage for decontamination pending subsequent final disposal.
By the end of this year, it is planned to dispose of a second PGV-1000 steam generator from Balakovo NPP. The first steam generator that arrived to Saida Bay came by train to Murmansk and was reloaded to the floating dock Itarus in Murmansk before sailing to its final destination.
