Equipment required for reactor pressure vessel annealing has been delivered to the Armenian nuclear power plant.

The annealing will be carried out as part of the project to modernise and extend the life of unit 2 of the Armenian NPP. The plant will be prepared for the final part of the work on extending its service life, which will take place in 2021 – the reactor will be annealed, which will allow it to return to 80-85% of its original state by, the press service of Rosatom reported on 4 September.

“This is an important science-intensive work to improve plant safety. Annealing will restore the characteristics of the metal of the reactor vessel, which will allow it to be safely operated in the future,” said Yuri Sviridenko, manager for the life extension project.

The vessel will be annealed after the fuel assemblies have been unloaded into the used fuel pool. The vessel will be inspected and the equipment installed in the reactor. Using an annealing unit, the reactor vessel will be heated to a temperature of 475 degrees Celsius, kept at this temperature for several days, after which it will slowly cool down.

The procedure will be carried out by several Rosatom organisations, each of which is responsible for its own segment of the work.

This technology for recovery annealing of the reactor vessel metal was first applied in 1987 at Novovoronezh 3. Now this procedure is carried out at all plants requiring service life extension. Reactor pressure vessel annealing has already been completed at VVER-440 reactors at Kola in Russia, Rovno in Ukraine, Kozloduy in Bulgaria and Loviisa in Finland.

Unit 2 of Armenian nuclear power plant was reconnected to the grid on 1 September after being closed for scheduled repairs, Rosatom said.

“The work performed has made it possible to significantly increase the level of safety and reliability of the power unit. Preventive maintenance at the Armenian NPP was completed 12 days ahead of schedule,” Rosatom said. “This was possible due to the efficient organisation of the process, the focus of the personnel of the Armenian NPP on results, as well as mutual understanding and effective business relations with the involved organisations that were developed during the joint work."

Rusatom Service, part of Rosatom’s electric power division, was the general contractor for the work. “For the fifth year now, the Armenian NPP has been combining maintenance work with the implementation of a programme to extend the life of the plant, since most of the activities in this direction are technologically available only when the unit is shut down,” Rosatom noted. After completion of the maintenance activities, life extension work continues.

Armenia’s state programme provides for the extension of the operating life of the existing NPP unit until 2026, as well as the phased commissioning of new units. Funding was provided by a Russian state export loan of $270 million and a grant of $30 million for up to 15 years. However, earlier this year Armenia  refused to extend the loan preferring to finance further work at its own expense. The Armenian government provided a budgetary loan to the Armenian NPP in the amount of $131.38 million for 2020-22, while the cost of the agreement with Rusatom Service is limited to $40.255 million.

The two-unit Armenian nuclear plant was built in the 1970s, but was closed following the Spitak earthquake in 1988. Metsamor 2 restarted with Russian assistance in 1995 in the face of severe energy shortages.