Source: National Research Council Canada

Atomic Energy of Canada Limited (AECL) reported that the unplanned National Research Universal (NRU) reactor shutdown on May 14 was safely conducted. The shutdown occurred due to a loss of electrical power in eastern Ontario and western Quebec.

However, during routine monitoring in the early morning hours the following day, a small leak of heavy water was detected within the NRU reactor facility, according to AECL. The leak rate is estimated to be at about 5 kg/hr. The heavy water is fully contained and is being stored in specially designed drums. The location of the heavy water leak has been identified at the base of the reactor vessel, where there is corrosion on the outside wall. 

The firm is currently considering repair options, and "activities are being planned." As a result, AECL anticipates that the NRU reactor will remain out of service for more than one month.

AECL expects to meet its production requirements for medical isotopes for the coming week. However, based on the current delivery schedule, production will be unable to meet demand, beginning May 23. The AECL has notified Health Canada, and MDS Nordion of the current situation.

The Canadian Nuclear Safety Commission (CNSC) was first notified on May 15 and the AECL will continue to provide updates to the CNSC and stakeholders when new information becomes available. AECL noted that there is no threat to workers, the public, the environment or nuclear safety related to this event. 

The NRU reactor has been in operation since 1957 and "produces the majority of the world's supply of critical medical isotopes," according to the company.