The Chalk River nuclear reactor will be shut down until at least late 2009. (The Canadian Press)

The nuclear reactor at Chalk River, Ont. — normally a major world supplier of medical isotopes — will be out of service until at least late 2009, Atomic Energy of Canada Ltd. officials said Wednesday.

The reactor could be closed even longer if there are delays in the inspection and repair process, according to the president of the Crown corporation, Hugh MacDiarmid.

"We are now able to advise that the [reactor] will not return to service before late 2009," MacDiarmid said during a news briefing.

"We are very conscious of the impact of an unplanned reactor shutdown, and we recognize the concerns and planning needs of the health community, patients and isotope producers."

A leak of radioactive water was detected inside the reactor on May 15, forcing a shutdown that AECL officials initially estimated would take about three months to fix. Since then, workers have been visually inspecting the leak by lowering cameras through small holes at the top of the reactor.

The 52-year-old Chalk River reactor normally produces about a third of the world's supply of medical isotopes, which are required for cancer and heart disease tests around the world.

Raitt, Aglukkaq 'disappointed'

The federal health and natural resources ministers issued a joint statement Wednesday saying they are "disappointed" with the announcement of the delay and warned the health-care industry to prepare for further shortages of medical isotopes.

"We expect a period of more critical shortage during the month of August," said the statement from Health Minister Leona Aglukkaq and Natural Resources Minister Lisa Raitt.

"For this reason, careful management of available supplies by the health-care community and the successful identification of alternatives will remain essential."

The government has directed AECL to give "paramount priority" to bringing the Chalk River reactor back to service as "quickly and safely as possible," said the ministers.

3-phase return

MacDiarmid said the first phase of a three-phase return-to-service schedule should be completed by the end of July. That includes an assessment of the condition of the National Research Universal (NRU) reactor and a decision on which repair method to use.

Roughly 60 per cent of the NRU's circumference has been examined. Inspectors have found thinning of the wall at the leak site, as well as nine other "areas of interest."

Phase 2 includes the actual repair and will take at least two months.

During the final phase, officials will restart and test the NRU, as well as reload its fuel supply. This process, which will eventually lead to the production of isotopes, will take roughly two months, he said.

MacDiarmid defended earlier public suggestions the NRU could have been up and running by the end of August. In late May, AECL senior vice-president and chief nuclear officer Bill Pilkington said that preliminary inspection data suggested the NRU could be operational within three months.

"The original guidance that we gave on the minimum three months was at a very early stage in the project," MacDiarmid said.

"We had not at that time yet made the decision to remove the fuel and the water from the reactor. We did not know fully the extent of the repair that would be required.… We felt it was still conceivable that a repair technique could be effective that would allow us to return to service in as little as three months."

When asked whether the delay in operations could stretch into 2010, MacDiarmid said he would not engage in "speculative questions" but said he is confident the reactor will be restarted.

"All evidence to date suggests the reactor can be returned to service," said MacDiarmid.

Currently, nuclear reactors in Europe and South Africa are producing about 70 per cent of the world's supply of medical isotopes.