The aging nuclear reactor in Chalk River, Ont., is still in need of repairs and will remain off-line until the end of the year, Atomic Energy of Canada Ltd. announced Wednesday.

Hugh MacDiarmid, the president and CEO of AECL, said it will be some time before the Crown-owned reactor that produces about one-third of the world's isotopes is up and running again.

"We're now able to advise that the NRU will not return to service before late 2009," he told reporters gathered at a Toronto news conference on Wednesday morning.

The 52-year-old NRU reactor has been down since May 15, when a heavy water leak was discovered.

AECL had initially projected that the reactor would be ready to go back online in about three months.

But a few weeks later, MacDiarmid said that timetable was "optimistic" and on Wednesday, he said AECL has yet to complete the first phase of a three-part repair process on the reactor.

The first phase of the repair process involves a "condition assessment" and determination of repair strategy, said William Pilkington, the chief nuclear officer at AECL.

Reactor leak investigation

While investigating the heavy water leak, Pilkington said AECL found nine areas in the reactor that needed further inspection.

Three of these areas must now be repaired, and a fourth may also require repair as well, he said.

In a news release issued Wednesday morning, AECL said "a decision on the repair method is expected in the next few weeks."

The second phase will see the repairs take place, a process that AECL estimates will last about two months, "depending on the method determined, regulatory considerations and further analysis of the extent of the repair required."

The final phase involves the restarting and testing of the reactor. AECL believes this phase will also take about two months to complete -- similar to the length of time it took to refill, refuel and restart the reactor in 1992.

MacDiarmid admitted that there is some uncertainty in the timetable on the reactor repair, but he defended AECL's efforts to keep the public informed on its progress.

"We feel a very strong obligation to transparency, and to providing the community with the best information we have when we have it," he said.

Isotope supply issues

MacDiarmid said it was AECL's "top priority" to get its NRU reactor up and running, so it can get back to producing isotopes.

Some critics, however, are skeptical that it can be fixed.

"My gut feeling is telling me that this reactor may never be reactivated," said Dr. Jean-Luc Urbain, head of the Canadian Association of Nuclear Medicine.

At a meeting in Toronto last month, nuclear medicine experts and representatives from isotope-producing countries met to try to sort out the supply problem that emerged in the wake of the shutdown of the Canadian reactor.

Two other reactors -- one in the Netherlands, the other in South Africa -- have ramped up their own isotope production to compensate for the lack of Canadian production.

On Wednesday, the head of the Ontario Association of Nuclear Medicine, said Canadian medical professionals are so far surviving the isotope shortage, but they have also been making compromises.

"In general what we've been doing is using different procedures ... using older types of medical isotopes that we used to use 10 to 15 years ago, we have reinstituted that usage," Dr. Christopher O'Brien told CTV News Channel in a phone interview from Brantford, Ont..

"What we're finding, however, is on a day-to-day basis, our ability to respond to emergency requests is compromised."

Reactor politics

On Wednesday, some Liberal MPs criticized the Conservative government's handling of the reactor and the subsequent isotope shortage.

"We're sick of getting the run-around from this government while cancer and cardiac patients compromised by isotope shortages get sicker," said Carolyn Bennett, the Liberal health critic.

"No more obfuscation about outdated medical techniques. No more pretending other countries are sending more isotopes our way when they aren't. No more passing the problem off to the provinces. We are asking for federal leadership and demand to see their action plan now."

The reactor shutdown and the resulting isotope shortage have been controversial issues for the Conservative government, which has indicated that it intends to pull Canada out of the isotope business in the long run.

On June 10, Prime Minister Stephen Harper said that the plan is to keep the NRU reactor running for as long as possible, while preparing for the day when other countries and businesses will take over Canada's share of isotope production to meet global demand.

In a joint statement released Wednesday, Health Minister Leona Aglukkaq and Natural Resources Minister Lisa Raitt said they were "disappointed" to hear about the reactor repair delays.

"We understand that AECL's announcement today ... is of concern to Canadians. We are likewise very concerned about and understand the seriousness of the effect of this announcement on Canadian families," the ministers said.

With files from The Canadian Press