TORONTO (AP) — About 800 nuclear scientists, engineers and technologists at a Canadian nuclear technology company hit the picket lines Monday after negotiators failed to reach a contract before the strike deadline, said the union representing the workers.

The Society of Professional Engineers and Associates, which represents workers at Candu Energy Inc., said that power plants will not shut down but there will a noticeable effect on operations.

"There's not enough people to replace us, so work will definitely be impacted," union spokeswoman Michelle Duncan said.

Candu Energy supplies more than 22,000 megawatts of power at sites around the world, via pressurized heavy water reactors. There are Candu-designed nuclear power plants operating in India, Pakistan, Argentina, South Korea, Romania and China.

The Montreal-based engineering giant SNC-Lavalin owns Candu, whose reactors supply nearly 16 percent of Canada's overall electricity requirements with operations in Ontario, Quebec and New Brunswick.

The union said the main sticking points in the labor dispute involved wages and seniority.

Union president Peter White said a key issue is what he calls the company's desire to move away from nuclear industry standards and compensate its employees differently from other workers in the field.

He said a full strike threatens the future of Canada's nuclear industry as it will almost certainly guarantee the loss of technological talent.

Senior engineers with years of expertise are choosing to leave the company, which could cause the design and service capabilities at Candu to decline, he said.

Duncan said the union would like to return to the bargaining table, but will only do so if SNC-Lavalin presents "a fair and competitive deal."

"We need to be competitive if we're going to maintain the expertise," she said.

"Our members can work anywhere in the world, they are employable and they are making their decisions by walking with their feet."

The federal government agreed last year to sell the Candu reactor division of Atomic Energy of Canada Ltd. to SNC-Lavalin for CA$15 million (US$14.7 million) plus future royalties.

Under the deal, SNC agreed to protect about 1,200 Atomic Energy jobs.

Shares in the company were down 15 Canadian cents (14 U.S. cents) at CA$38.06 (US$37.27) on the Toronto Stock Exchange on Monday afternoon.