UPDATE 1-Areva board decided to sell T&D unit-union

* Areva's board agree to sell T&D unit - CGT source

* Sale in one block, depends on price and job guarantees

* sales would take place before the year-end

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PARIS, June 30 (Reuters) - Areva's (CEPFi.PA) supervisory board has approved a project to sell the French state-controlled nuclear reactor group's power transmission and distribution (T&D) business by the end of the year, a union source said.

"The supervisory board has voted in favour of a project to sell T&D before the end of the year," Alain Nagel, a representative of French union CGT on the Areva works council, told Reuters by telephone.

"T&D would be sold as one entity under these conditions: a sufficient price and social guarantees."

The sale of T&D was among a package of measures aimed at bridging Areva's 11 billion euro ($15.40 billion) funding gap.

The opening of Areva's capital to new investors, the sale of minority stakes and debt were other measures under review.

(Reporting by Benjamin Mallet, Editing by Marcel Michelson)