Thursday, December 13, 2001

By Alan Irving

Calder Hall power station at Sellafield is shut down for investigations. BNFL, facing more heavy financial losses, cannot say when the four nuclear reactors will start up again.

The indefinite shutdown is expected to cost operators BNFL millions of pounds in lost electricity generation to the national grid, although vital energy supplies to the Sellafield site, especially for reprocessing, are being met from other sources.

The 300 hundred Calder employees will continue to be employed on various reactor work.

It is believed that enforced shutdowns could cost BNFL at least 30,000 for each reactor per day.

Only a few months ago the world's first commercial nuclear station (opened by the Queen in 1956) celebrated its 46th anniversary in a series of parties for the workforce but all the reactors are now out of operation for what may be the first time ever.

Checks are under way to discover whether there are any problems with the graphite chargepans which are used to guide the highly radioactive used fuel rods into place.

This is because at Chapelcross - Calder's sister station - one of the chargepans was found to be slightly tilted and misaligned due to what BNFL call "the well known phenomenon of radiation-induced graphite shrinkage."

The Calder Hall checks are described as a precautionary measure, although the reactors at both sites are of the same design.

A serious incident at Chapelcross last July involving a spent fuel basket saw BNFL put a self-imposed ban on refuelling its Chapelcross reactors when each became due for annual maintenance. At Calder Hall last week, Reactor I became the last to be put out of service.

Union officials were yesterday meeting with management to get a full briefing on the situation.

As Calder Hall which employs about 300 people, is already due to close in four years time, there is already speculation and worry on the site that if cost and risk assessments prove too high BNFL could decide to cut its losses and go for an earlier closure.

But yesterday BNFL insisted: "All reactors will be returned to service as soon as possible next year. It is too early to set specific dates at this stage."

The chargepans consist of cast iron guide plates which sit on top of the graphite cores.

A BNFL spokesman said: "Detailed chargepan inspection work is now being carried out on all of the Calder Hall reactors, the results of which will lead to the development of revised safety cases together with options for any necessary modification work."

The first word of something being wrong came from Sellafield director of operations Brian Watson at a meeting of the Sellafield Local Liaison Committee, the site's community channel for health and safety matters.

He said: "Calder Hall is currently in some difficulties, significant outage (maintenance) work being undertaken.

"The impact of the recent incident at Chapelcross has meant that we have not been able to secure permissions to recharge the reactors and there is a further problem to do with an item within the reactor called the chargepan. There is an issue with the positioning of those steel plates and we are currently looking at how we can justify the re-start of the reactors and taking a safety case to the NII.

"It does mean that, very shortly, we are likely to be in a situation of having none of the reactors operating."

The reactors cannot become operational again until the NII agrees new safety cases.

Meanwhile, Sellafield is receiving its essential steam and electricity supplies from a non-nuclear source - the Fellside combined heat and power plant, on the site.

Sellafield spokesman Jamie Reed said: "There is no risk to safety and at no time have the reactors operated unsafely.