A dispute over pay by workers at the Sellafield site is continuing, although staff have returned to work.
Unite members, who work for sub-contractors at the West Cumbrian nuclear complex, began industrial action in September.
They are demanding site-specific allowances, which they claim are paid at other nuclear sites.
The union has to notify Cumbria police at least six days before planned industrial action and no notification has been given since the middle of last month.
Union members also did not strike from December 22 to January 2.
A Unite spokesman said: “No strike action is currently taking place and our members have returned to work.
“The dispute is still ongoing and we continue to request negotiations with the employer through normal channels.
“Any further industrial action will be made public.”
We asked if a ballot was planned for members and the spokesman added: “Not at this time.”
According to Acas, once a ballot is held, the union has six months to take action, then it must ballot union members again to determine what action to take.
Sellafield Ltd is not involved in the dispute. Previously, a spokesman told Cumbria Crack: “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.”
Unite has previously said the companies involved in the dispute 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.
