British Nuclear Fuels (BNFL) has put on hold plans to cut the number of union officials at Sellafield.
Workers staged a number of walkouts last year
The Amicus and GMB trade unions had accused the firm of a "vindictive attack" by planning to cut union officials posts.
Union leaders threatened more industrial action if the proposal was not withdrawn.
On Thursday, BNFL withdrew the plans and said it would consider the posts at the next review of employee relations.
Thousands of workers at the nuclear reprocessing plant in Cumbria staged a series of strikes at the end of last year in a row over the pay gap between white collar workers and manual staff.
It was the first time in almost 30 years that the plant workers had staged a walkout.
Last month, union members voted 6 -1 in favour of a deal that would see shift bonus rates for workers harmonised by October 2006.
On Wednesday evening, Amicus warned that if the proposals to cut the number of representatives from 11 to four were not withdrawn, then it and the GMB would hold another ballot for industrial action.
BNFL had claimed it was reducing the number of officials from eight to six, following a review that began before the pay dispute.
But the firm agreed with the national officers to consider the Sellafield trade union posts at the forthcoming review of employee relations at the site.