A report in the Ottawa Citizen stated that AECL will evaluate repairs to the reactor's water containment vessel, which two years ago experienced a leak that forced the closure of the NRU for 15 months, beginning in May 2009.

Since going back online eight months ago, the NRU has been operating on a 28-day cycle, including regularly scheduled five-day outages for maintenance and other supporting operations, according to AECL.

"We are pleased with the performance of the NRU reactor and the progress of the corrective action plan following the restart last summer," said Hank Drumhiller, vice president of operations and chief nuclear officer at AECL Nuclear Laboratories, in a communiqué to the Canadian Nuclear Safety Commission.

AECL added that all demands for medical isotopes have been met during this period, and planning is ahead of schedule for NRU's planned 33-day outage.

The reactor is scheduled to return to service on June 17.