The Nuclear Installations Inspectorate (NII) has given the ageing facility on Anglesey the go-ahead after reactor faults forced its shutdown.

Owners BNFL Magnox lost £400,000 each day the plant was offline - their bank balance is now £180m slimmer. They have now satisfied inspectors the reactors have been made safe.

BNFL have fixed the faults at Wylfa

But environmental pressure group Greenpeace has been calling for the plant to be permanently decommissioned.

The station opened in 1970 and has a licence to run until 2004, but the group told the Welsh Assembly in March that safety problems would increase as the plant aged.

Local action group PAWB - People Against Wylfa B - which is also advocating decommissioning, has said it would be unsafe to restart the reactors.

Dylan Morgan from PAWB said: "We are very alarmed that this has go ahead. What we are seeing once again is an all pals agreement between NII and BNFL.

"The only information which is in the public domain about the extent of the problems at Wylfa conclude that there could be catastrophic consequences if the welds broke."

Last April, inspectors found faults on welds holding pipes in place as they enter nuclear reactors.

There were also incidents earlier, last January and in December 1999, which raised safety concerns amongst local campaigners, although BNFL maintained there were no safety threats.

Inspectors satisfied

The company has satisfied the NII that the welds were still strong enough to withstand the pressures they would face. But it also agreed to fit giant specially-designed brackets as for secondary protection.

Power has now been switched back on at Wylfa, but it may be up to 10 days before the station begins generating electricity at full capacity.

A close watch will be put on the restart operation as rods are put back in to the reactor and temperature and pressure levels are monitored.

A fully functioning Wylfa will be seen as crucial to heavy electricity consumers in north-west Wales.

With plans to develop a gas-fired power station on the Rhosgoch site turned down, the continued supply to the Anglesey Aluminium plant is considered important.