OTTAWA - Prime Minister Stephen Harper inflamed the Chalk River isotope crisis by calling Canada's nuclear safety watchdog a "Liberal-appointee," says a government document.

Harper's remarks turned a few days of bad press into a full-blown saga akin to the Mulroney-Schreiber affair, says a briefing note prepared for Natural Resources Minister Lisa Raitt.

"It is clear that what might have been a relatively low-profile, or at least short-lived, medical isotope supply story became much more than that by political events, specifically, the prime minister's characterization of Linda Keen as a `Liberal-appointee,' and the subsequent demotion of Ms. Keen," it says.

Natural Resources prepared the briefing note to acquaint Raitt with her new portfolio when Harper appointed her to cabinet last fall.

The Canadian Press obtained the document under the Access to Information Act.

It analysed media coverage of the shutdown of an aging Atomic Energy of Canada Ltd. reactor in Chalk River, Ont., which sparked a critical global shortage of medical isotopes used in the diagnosis and treatment of cancer and heart ailments.

The 52-year-old reactor was closed for a few days in November 2007 for routine maintenance. During that time, the Canadian Nuclear Safety Commission discovered emergency backup power wasn't connected to two pumps which prevent a meltdown.

The shutdown lasted nearly a month until Parliament voted to bypass the regulator's order.

The prime minister insisted there was no risk of a nuclear accident.

"The government has independent advice indicating there is no safety concern with the reactor," Harper told the Commons in December 2007.

"On the contrary, what we do know is that the continuing actions of the Liberal-appointed Nuclear Safety Commission will jeopardize the health and safety and lives of tens of thousands of Canadians."

Atomic Energy's then-chairman, Michael Burns, resigned after the fiasco, and the Conservative government later fired commission head Keen for her refusal to authorize the restart.

Keen later sued the federal government over her dismissal.

"The issue of Ms. Keen's demotion became the catalyst for media commentary on the issue of the prime minister's relationship with the public service, an issue -- along with the prime minister's politicization of the affair -- that underpinned much of the Chalk River affair," the briefing note says.

The news analysis said the isotope crisis was "comparable in volume to the Mulroney-Schreiber affair."

Dimitri Soudas, a spokesman for Harper, said the prime minister was simply stating a fact when he referred to Keen as being appointed by the previous Liberal government.

"The government pointing out facts does not change anything in the severity of the situation, which was a shortage of isotopes," he said.

"Pointing out facts does not change the fact that the government was going through a health crisis, and Ms. Keen's inability to effectively manage and lead the commission resulted in the government removing her designation as president. That was what's at stake here."

He also played down the document's significance.

"I don't have the privilege to write those briefing notes. I guess whoever wrote it can comment on his position, his opinion, whatever the case may be," Soudas said.

The briefing note didn't surprise Keen.

"That was one of the things in my affidavit, was the fact that we felt that the prime minister had prejudiced the file by -- to the shock of everybody -- naming me in the House," she said in an interview.

She stands by her decision.

"I think what I did was right," Keen said. "No one wants to go through that. But I think you have to decide when you become a regulator, are you standing up for what you believe, or not."

Apparently the affair didn't shift Canadians' opinions on nuclear power or seriously hurt the Tories.

The note says survey research in January 2008 by Ipsos-Reid for the Canadian Nuclear Association showed 29 per cent of Canadians had less confidence in the nuclear industry than they did the previous year, and only a quarter of those people said it was because of Chalk River.

Another poll by Environics from December 2007 to early January 2008 found overall satisfaction with the government increased to 65 per cent, up eight percentage points from October 2007.