OTTAWA

The shortage of medical isotopes will last a little longer now that a leaking nuclear reactor at Chalk River is not going back to work until the end of the year.

Atomic Energy of Canada Ltd. said yesterday it would take at least that long to fix the aging National Research Universal reactor, which usually produces half the global supply of medical isotopes.

"We are now able to advise that the NRU will not return to service before late 2009," AECL president Hugh MacDiarmid said yesterday.

The agency has almost finished the first phase of its return-to-service plan, which means it has identified the problem and is deciding how best to fix it.

Actual repairs are expected to take at least another two months and then restarting the reactor -- which has been shut down since a heavy-water leak was discovered mid-May -- will require a minimum of two months more.

The agency originally said the reactor would be down for a month and then kept saying at least three months until the announcement yesterday.

MacDiarmid said his company gave the three-month timeline "at a very early stage in the project," before AECL knew it would have to remove fuel and water to do the repairs.