Rosatom head Sergei Kirienko praised work to develop technical solutions to enable the world's oldest RBMK reactor to continue generating during a visit to Leningrad-1. The fate of the unit will be made clear by 1 November.

The 925 MWe unit, in commercial operation since 1974, has been off line since May 2012 because of deformation of its graphite moderator. Work is currently under way at the plant to investigate whether it will be feasible to bring the unit back into operation. Russian contractor Titan-2 has been carrying out preparatory work towards the restoration of the graphite stack since February. The work will involve the replacement of up to 350 process channels, according to Titan-2.

The main phase of development work towards resolving the issue is due to be completed by the summer, and Kirienko said that solutions would be applied by the second half of October. A final decision on the plant's future would then be made by 1 November. Kirienko promised that safety would remain the priority. The solutions that had already been developed were without parallel in either the Russian or world nuclear industry, Kirienko said.

The RBMK is a light water-cooled reactor with individual fuel channels surrounded by the graphite blocks that form the reactor's moderator. Each channel is individually cooled by pressurised water which is allowed to boil in the tube. After 1986 Chernobyl accident measures were implemented to improve safety and RBMKs continued to operate in Russia, Lithuania and Ukraine. All of the 11 RBMKs remaining in operation today are in Russia, including the four units at Leningrad. Two VVER-1200 pressurized water reactors are under construction at a second Leningrad site, the first of which is due to enter service later this year.

Russian nuclear plant operator Rosenergoatom is to investigate the graphite stacks at all of its RBMKs this year, so the development work being carried out at Leningrad 1 will be of relevance to the rest of the RBMK stable.

Source: World Nuclear News