Amec, the project management and services company, has bought French nuclear engineering company ATM Enterprise for *20.5m (£14.2m).
Amec already owned a stake in ATME, after Peroue Spie Capital, in which Amec has a 49% stake, bought the company formerly known as Game Nucleaire last April.
Amec has bought out the 51% shareholder in Peroue Spie Capital - Peroue Conseils.
ATME employs 620 people and achieved a *41m (£28m) turnover in 2005. A statement on Tuesday said the acquisition would strengthen Amec Spie's nuclear services business.
Amec put Amec Spie up for sale last November. Last year it made a profit before interest, tax, and amortisation of £49.7m on a £1.75bn turnover.
At Amec's annual results two weeks ago, chairman Sir Peter Mason said the sale should be complete by the middle of this year.