BRITISH ENERGY'S Sizewell B nuclear power station in Suffolk has shut down for a month after the cooling system for the reactor head began to leak boric acid vapour in early May.
Engineers were this week working to replace the seals after the acid leak triggered a shut down of the reactor on 11 May. The release was contained by Sizewell B's pressure vessel, which contains the reactor and primary radiological shielding.
A British Energy spokesman said that reactor head seals on similar pressurised water reactors are replaced as a matter of course every 18 months. But operators of reactors in other countries have reported occasional interim failures. The leak was therefore 'not unusual', he said.