Managers of the Wylfa nuclear power station on Anglesey will attempt to restart one of the plant's two reactors after a weekend safety incident.

Both the station's reactors were shut down on Sunday after a refuelling operation went wrong.

It emerged that a uranium fuel rod was not being held by a grab in the reactor.

An investigation is trying to determine whether the rod was dropped or if the grab had failed to pick it up.

Automatic shut down

The second reactor shut down automatically when the safety systems detected an "electrical disturbance" caused by the first incident.

The plant's operators, BNFL, said the incident was rated as zero on the international safety scale from 0 to 7.

Station manager Stuart Price apologised for the subsequent noise created when the reactor's steam was released.

Mr Price admitted that the steam discharge was "rather alarming" but there was no risk to anyone living in the area or people working at the plant.

"Nothing specially untoward happened - but our operating rules and procedures do call for us to shut down the reactor when something unexpected happens during refuelling," said Mr Price.

Prudent safety policy

"Safety always comes first - so whenever the slightest doubt creeps into the operation of nuclear facilities like Wylfa, we take the prudent and conservative approach and shut down," he added.

The uranium rod which was involved in the incident is one of 200 which are replaced at Wylfa every week.

It is estimated that it costs BNFL an average of £500,000 a day in lost revenue if it is not producing electricity.

A BNFL spokesman said that they planned to restart Reactor Two on Tuesday and Reactor One "sometime later this week."

A spokesman for the local campaign group PAWB, Dylan Morgan, said they were concerned about the incident at Wylfa.

Mr Morgan claimed there had been a number of accidents involving the reactor grab and he believed that the life of the power station should not be extended beyond 2004.