Workers at the Sellafield site are planning another two weeks of strike action from Monday.
The workers, represented by the Unite union, are demanding site-specific allowances, which they claim are paid at other nuclear sites.
They believe they should be paid the allowance because they work in a highly hazardous environment.
The workers are not employed directly by Sellafield Ltd, but by subcontractors on the site.
Unite said the companies involved were: Altrad Services; Amentum Clean Energy; Amentum Enterprise Asset Solutions; AVRS Systems; Balfour Beatty; Careys; DSD; Design Grid; Enigma; Erith; ES Steel Ltd; Flannery; Impwood; Kaefer; Keltbray; Kier; LEL Nuclear; Mammoet; Meldrum; Mitie FM Ltd; Mitie Ltd; Morgan Sindall; NG Bailey; NRL; Nuvia; PC Richardson; PPS Electrical; Rhodar; Shepley; Sir Robert McAlpine; VGC Group; William King; G&M Lawson Ltd; Athena; Stobbarts Ltd and FB Taylor (Cable Contractors) Ltd.
The union said the latest round of industrial action was being taken over a lack of progress in talks.
Cumbria Crack asked, on October 15, when the union last had face-to-face negotiations with the contract firms it was in dispute with.
Unite told us in response: “Unite have always been open to negotiations, we have highlighted that ACAS could be the vehicle if the employer wish to introduce them.”
It said that this latest industrial action, from October 27 to November 2, would involve workers from six subcontractors – Altrad, Enigma, ES Steel, Kaefer Ltd, Meldrum Ltd and PPS Electrical.
An overtime ban is also in place. Workers on strike receive pay from the union’s strike fund.
A Sellafield spokesman said: “The industrial action taking place at Sellafield is the result of a pay dispute between some Unite union members and their employers.
“As the people involved are not employed by Sellafield Ltd this is not a dispute that we can resolve.
“Our priority, as always, is to maintain the safety and security of the Sellafield site.
“We have provided guidance to our employees who may be impacted in travelling to the site during the action.
“We will also continue to support Cumbria police as they work to minimise the impact of the action on the local road network.”
Workers last walked out at the beginning of this month and caused misery for thousands of commuters and people living near the area as they employed slow march tactics.
Dubbed the Sellafield shuffle, it saw them take around five hours to complete each day, holding up traffic and causing long delays.
It even prompted a song to be created in response to the strikers.
You can hear it below – but warning, it contains very strong language:
