OTTAWA - Canada's nuclear medicine community was "teetering on the brink of disaster" during last year's controversial reactor shutdown, an expert medical panel has found.

In a newly released report, an ad hoc group of health experts urges Ottawa to build more facilities to supply medical isotopes, lessening dependence on an aging research reactor that produces half the world's supply.

In the midst of last year's isotope crisis, Health Minister Tony Clement commissioned a group of 10 medical experts to advise the government on the health-care consequences of the shutdown of the Atomic Energy of Canada Ltd. reactor in Chalk River, Ont.

Their report, dated May 2008, was posted on Health Canada's website on Monday.

It says the nuclear medicine community, which depends on radioactive materials to diagnose and treat diseases, was ill-informed while the reactor was off-line and as a result could not schedule some patients for treatment.

"For patients with serious and often life-threatening conditions, the lack of certainty was chilling," the report says.

"In some circumstances, patients and their health-care providers had to decide whether they would resort to procedures known to have higher risks or to be less accurate."

The shutdown of the aging reactor led to a critical global shortage of medical isotopes used in the diagnosis and treatment of cancer and heart ailments.

The 51-year-old reactor was initially closed for a few days last November for routine maintenance. During that time, the Canadian Nuclear Safety Commission discovered that emergency backup power wasn't connected to two pumps which prevent a meltdown.

The subsequent shutdown lasted nearly a month until Parliament voted to bypass the regulator's order. The reactor was restarted Dec. 16.

The Conservative government later fired then-commission head Linda Keen for her refusal to authorize the restart.

Douglas Abrams, one of the report's authors, says it's important the nuclear medicine community has a diverse and reliable supply of medical isotopes.

"These reactors always are set up to be maintained, and they are complex machines, and things can go wrong with them," he said.

"We certainly need to have another supply venue open to us."

The health experts' report recommends the government do a better job keeping the public and the medical community informed during a crisis.

A separate but related report also released Monday singles out a breakdown in communications as a trouble spot plaguing the regulator and Atomic Energy.

The report by an independent consultant, Talisman International, says the shutdown could have been avoided with improved communication, clear licence conditions and a shared understanding of issues surrounding the reactor.

The Talisman report blamed both the nuclear safety commission and Atomic Energy for the shutdown.

It says the commission's obtuse regulatory language failed to specify what safety upgrades needed to be made in order for Atomic Energy's operating licence to be renewed in 2006.

Talisman says the regulator used terms like "expectations" and "we are asking AECL" rather than listing specific requirements.

The report says this sort of vague language created a situation where Atomic Energy declared the reactor "fully operational" in December 2005, but neglected to mention that the emergency power back-up wasn't connected.

Greenpeace nuclear critic Shawn-Patrick Stensil says neither Atomic Energy nor the nuclear safety commission were sure what their obligations were.

"Fundamentally, one of the problems is that none of the rules were clear from the outset," he said.

The Talisman report says staff at the nuclear safety commission knew the reactor lacked key safety measures, but they did not tell management.

The communications breakdown perpetuated the nuclear watchdog's belief that all safety upgrades had been made to the reactor's two most crucial heavy-water pumps, the report says.

"Consequently, the status of the (emergency power supply) connections was not effectively communicated within each organization and between organizations."

A separate internal report prepared earlier this year by the nuclear safety regulator and Atomic Energy also deemed communication between the two organizations as a trouble area.

The Talisman report also says Atomic Energy failed to keep tabs on safety upgrades to the reactor.

"Despite the fact that these connections were part of the (emergency power supply) upgrades planned by AECL, by 2007 this safety upgrade was not being tracked in the . . . commitment tracking system."

A spokesman for the nuclear safety commission said the regulator was still deciding whether to comment on the Talisman report's findings. Atomic Energy head Hugh MacDiarmid was not immediately available.

The federal government is currently reviewing Atomic Energy, which employs 4,800 people, to determine its future. Some have speculated it may be spun off into private hands or sold to a foreign company.

In May, Atomic Energy announced plans to scrap development of its two MAPLE medical-isotope reactors after pouring hundreds of millions of dollars into the failed nuclear project.

MDS Inc., which has an exclusive 40-year contract with AECL to buy isotopes, is now suing the company and the federal government for $1.6 billion for abandoning the two MAPLE reactors.

Atomic Energy has said it will instead rely on the NRU reactor to supply medical isotopes.