About 700 nuclear scientists, engineers and other workers with Candu Energy Inc. walked off the job Monday morning after late-night talks failed to produce a new contract.

On Friday, the Society of Professional Engineers and Associates, the union representing the workers, had served notice that a strike would be in effect as of 6:30 a.m. Monday in the absence of a new deal.

Striking workers were to set up picket lines across the country, including outside the Chalk River facility in Ontario, as well as in Quebec and New Brunswick.

Peter White, president of the SPEA, said in a statement the labour strife would have “dire consequences” for Canada’s nuclear industry.

"Our senior engineers, who have years of experience and expertise, are choosing to leave Candu Energy," White said in a statement.

Candu is a subsidiary of SNC-Lavalin, with about 1,400 employees. The company says its reactors supply about 50 per cent of Ontario’s electricity, and 16 per cent of Canada’s electricity.

The company also says it has the capacity to provide about 22,000 megawatts of power at sites around the world.

Workers voted overwhelmingly in favour of a strike back in May. However, negotiations between the company and the union continued.

According to a “strike flyer” posted to the union’s website dated July 3, issues that the two sides remained at odds over included pensions, salary increases and seniority among workers.