TORONTO -- Ontario Power Generation has awarded two more contracts for refurbishment work at the Darlington nuclear power plant to a joint venture formed by SNC-Lavalin and the Aecon Group.

Aecon (TSX:ARE) will perform 60 per cent of the work in a $265-million contract to overhaul all four of the power plant's steam turbine generators and related equipment. SNC-Lavalin )TSX:SNC) will do 40 per cent of the work under that contract.

The second contract, worth $127 million, includes construction of a building that will house equipment for processing radioactive waste from reactor components. The work for that contract is split 50-50 between the two companies.

In January, the joint venture was awarded a $2.75 billion contract to extend the life of Darlington's four Candu nuclear reactors -- which produce about 20 per cent of Ontario's electricity.

The reactors will be taken out of service for about three years apiece until the overall job is completed in about a decade. The overhaul is intended to extend each reactor's life by 30 years.