A nuclear medicine technologist assists a patient in Toronto in May. Isotopes used in medical imaging have been in short supply while the Chalk River nuclear facility idles.A nuclear medicine technologist assists a patient in Toronto in May. Isotopes used in medical imaging have been in short supply while the Chalk River nuclear facility idles. (Chris Young/Canadian Press)

Atomic Energy of Canada Ltd. says it estimates that the National Research Universal reactor will resume medical isotope production by the end of July.

The NRU reactor in Chalk River, Ont., has been off-line for more than a year for repair of a radioactive water leak.

Doctors who rely on medical isotopes to diagnose ailments have said they are frustrated it is taking so long to repair the leaky reactor.

AECL said detailed inspections of the repair by the Technical Standards and Safety Authority have declared the reactor fit for service.

Some inspections were repeated following an earthquake last week but AECL said no changes were detected.

AECL will appear next Monday at a Canadian Nuclear Safety Commission hearing considering an application to restart the reactor.

AECL said the reactor is in a safe shutdown state and return-to-service activities are in progress.