Both sides say safety will not be affected during the strikes

Members of the GMB and Amicus unions at the Cumbrian site, staged the first in a series of one-day strikes on 14 November and are to walk out again every Friday up to 12 December.

The Amicus union says the majority of Sellafield's 24 shift working plants have either been shut down indefinitely or are working at reduced capacity because of the strike action, at a cost of millions of pounds.

It says this compares to the �4.8m a year it would cost to harmonise pay at the site, the issue the strike is over.

The plant's owner, British Nuclear Fuels Limited (BNFL), says it is frustrated over suggestions it has not treated the unions fairly and both parties will have to count the cost once the dispute is resolved.

The Sellafield management team need to stop being so bloody minded and pay our members what they owe Amicus National Officer for Energy, Dougie Rooney

Amicus national officer for energy, Dougie Rooney said: "This is a ridiculous situation.

"BNFL are claiming they can't afford to meet their written promise to harmonise shift pay for shift workers but the weekly strike action at the plant is actually costing them more.

"The weekly strikes have effectively shutdown Sellafield and have sustained unnecessary losses for BNFL.

"The Sellafield management team need to stop being so bloody minded and pay our members what they owe."

Both sides have said they are committed to safety at the plant during the strikes.

In a statement, BNFL said: "The priority of the managers at Sellafield is to manage the site in the long term interests of the country.

Shift pay

"We recognise that this industrial action will inevitably have cost implications for both the company and the strikers, but both parties will have to count the costs once the dispute is resolved."

Unions say BNFL made an agreement to harmonise the �2,000 difference in shift pay between industrial workers and staff by April 2004.

But it says the company has only offered to begin the process in April 2004 and not complete it until April 2009.

But BNFL says it is frustrated over suggestions it has not treated the unions fairly over the issue.

Director of Sellafield Brian Watson said: "Despite the continued industrial action, our position has not changed. We are prepared to talk to the unions on any issue - but first we need a process."