Concerns were raised after 50 workers staged a lunch-time walkout at Kilroot Power Station in Carrickfergus in February 1986.
The protest at the station on the outskirts of Carrickfergus, was “based on a misconception” according to a spokesperson from the Northern Ireland Electricity Service.
The workers’ action was sparked by a statement issued by two DUP Assemblymen.
They had claimed that 14 engineers from the Republic of Ireland had been given security clearance for special training at the power plant.
The Assemblymen said that they would name the trainees from the Republic’s Electricity Supply Board and maintained that the move, which equips Irish workers to help run power stations in Northern Ireland, was connected with the Anglo-Irish Agreement.
A NIES spokesperson said: “The training of a party of trainee engineers from the ESB is on a fee-paying basis.
“For some years now we have been training ESB staff on the generation simulator at Kilroot.
“This has absolutely no relevance to operating power stations in Northern Ireland or to the Anglo-Irish Agreement.”