O&M and upgrade |
Armenians warm to VVER-440 life extension
Vessel anneal completed at Armenia’s VVER-440 pressurised water reactor
Above and right: Annealing equipment at Armenian NPP unit 1 (source: Rosatom)
Rosatom reports that annealing has been carried out on the pressure vessel of Armenian NPP unit 2, a Russian-design VVER-440 pressurised water reactor. The aim is to extend the service life to at least 2026. The annealing operations took place in the reactor hall of the plant with the reactor vessel in situ. The annealing equipment, with a height equivalent to of a two-story building, was delivered to the power plant in pieces, then assembled and installed in the reactor vessel. The vessel metal was slowly heated to a temperature of 475°C, held for 150 hours and then gradually cooled. The whole process took ten days.
The reactor vessel is considered to be a non-replaceable component of a nuclear power
plant. Annealing will restore the vessel material “operational characteristics” to “80-85% of the original state”, says Rosatom. The Russians have pioneered vessel annealing as a life extension measure, with the first application at a nuclear plant that at Novovoronezh 3 (also a VVER-440) in 1987. The technology was developed by Rosatom subsidiary CNIITMASH.
The annealing project in Armenia was performed by Atomenergoremont (a subsidiary of nuclear plant operator Roenergoatom, itself a subsidiary of Rosatom) and power plant staff, together with OKB Gidropress, CNIITMASH, Kurchatov Institute Research Center and CNIIKM (“Prometheus”). The overall modernisation project “general contractor” is Rusatom Service (also part of Rosatom).
Above: Here’s one we did earlier: VVER- 440 pressure vessel annealing operations underway at Kola (source: Rosatom)
Atomenergoremont was able to draw upon VVER-440 vessel annealing experience gained in Russia (Novovoronezh 3 and Kola), Bulgaria (Kozoloduy), Ukraine (Rovno) and Finland (Loviisa).
42 | October 2021 |
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“Reactor vessel annealing technology is a piece of Russian know-how that has good export potential”, believes Anatoly Chukharev, Rosenergoatom director of international business development. He notes that in 2018, Rosenergoatom, with the assistance of OKBM Gidropress and the Kurchatov Institute, for the first time ever, annealed the pressure vessel of a 1000 MW PWR, Balakovo unit 1 (a VVER-1000), allowing service life to be extended by 15 years.
The Armenian NPP, with two Soviet-supplied VVER-440-V230 units, was built in the 1970s but was closed following a devastating earthquake in 1988. However, unit 2 was recommissioned with Russian help in 1995 in response to severe energy shortages.
In March 2014, the Armenian government decided to extend the plant’s service life up to 2026. The work is supported by a Russian loan and grant.
Armenian NPP 1 plays a key role in Armenia’s energy supply, currently accounting for about 39% of the country’s total electricity generation.
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