The new contract runs until Dec. 31, 2016 and includes a 3.6 per cent increase over six years in salary and merit increases.
Candu is owned by Montreal-based engineering giant SNC-Lavalin (TSX:SNC), and its employees design, build and service nuclear reactors that supply nearly half of Ontario's electricity and 16 per cent of Canada's overall electricity requirements.
The company has operations in Ontario, Quebec and New Brunswick. Reactors designed by Candu supply more than 22,000 megawatts of power at sites around the world.
The union has said the main sticking points in the labour dispute involved wages and seniority.
The Society of Professional Engineers & Associates said the difficult round of negotiations prompted it to give up many items but also "hold on to many things important to our members."
The approved deal removes the union's intention to litigate site seniority.
However, the bargaining committee claimed to have won a detailed definition of "project hire" and "site" that it said protect members from potential abuses of seniority at individual sites.
"This is not the collective agreement that we wanted but neither is it the agreement that the company wanted," union vice-president Michael Ivanco said in an update last week posted on its website.
"Whether this agreement helps to give our members sufficient incentive to remain with Candu Energy, only time will tell. We believe that SNC is going to regret its hardline approach to these negotiations."
The federal government agreed last year to sell the Candu reactor division of Atomic Energy of Canada Ltd. to SNC-Lavalin for $15 million plus future royalties.
Under the deal, SNC agreed to protect about 1,200 AECL jobs.
Ontario has awarded a contract worth more than $600 million to a joint venture between SNC-Lavalin Nuclear Inc. and Aecon Construction Group Inc. (TSX:ARE) to refurbish its Darlington nuclear station near Toronto.
However, Candu Energy's hopes of winning a refurbishment contract in Quebec appeared to have been dealt a blow when the incoming Quebec government confirmed Tuesday that it will close the Gentilly-2 nuclear plant as promised two years ago.
Eric Gamache, spokesman for premier-designate Pauline Marois, told The Canadian Press that the PQ government has no intention of changing its position.
The outgoing Jean Charest government decided in 2008 to spend nearly $2 billion to rebuild the plant, but put the project on hold after the catastrophe at the Fukushima plant in Japan and sent it for further study. Critics say the price tag has increased to $3 billion, which Hydro-Quebec has never confirmed.
Candu is also extending the life of a reactor in Argentina and pursuing new build reactor opportunities in Turkey, Argentina, Romania and Ontario.
In China, Candu is working on the development of recycled uranium and thorium as alternative fuels for its Gen-III EC6 Candu reactors, and in the United Kingdom Candu is conducting a study into providing alternative full lifecycle approaches for managing that country’s fissile material stocks.