The first unit of the Ignalina reactor will be shut down in 2005, under a plan that was agreed on 31 January by the Lithuanian government.

The two units at Ignalina are the largest RBMKs in operation – they were originally rated at 1500MWe when they started up in 1983 and 1986, respectively. Among the safety upgrades initiated at the plant since the Chernobyl accident in 1986, the units have been derated to 1300MWe apiece. Their closure has been under discussion for some time, not least because as long as the reactors stay in operation they are a bar to Lithuania’s plans to join the European Union. On the other side of the balance for Lithuania, the reactors provide some 70% of the country’s electricity and replacing it would be an expensive business.

Now the Lithuanian government has agreed detailed plans for shutting down the first unit, following a decision in principle taken by an earlier government, in exchange for grants of around $200 million from international donors – mostly from the European Union. The government has not said when or if it will shut down the second unit.

When unit 1 is shut down it will have been in operation for 20 years, often considered a decision time for RBMKs. In these reactors fuel is held in channels passing through the solid graphite core; as the channels age they may be renewed singly but after two decades a full rechannelling of the core may be required.