CHALK RIVER, ON, June 17 /CNW/ - Atomic Energy of Canada Limited (AECL)
provides the following status report on the unplanned shutdown of the NRU
reactor at its Chalk River Laboratories.
AECL reports that removal of the last NRU fuel rod was successfully
completed June 15. Removal of the remaining 15 control, adjuster and cobalt-60
isotope rods has begun. Seven of these assemblies were removed from the
reactor as of June 16.
Completion of rod removal and the subsequent removal of heavy water from
the reactor is expected to be complete by the end of this month. Final
preparations are underway to conduct a detailed inspection of the condition of
the reactor vessel using remote non-destructive examination techniques. This
task will be performed as soon as the remaining rods and heavy water have been
AECL is drawing on advice provided by its technical staff and industry
experts to determine the most effective options for vessel repairs. AECL
continues to work with industry experts on cleaning, inspection and repair
techniques for the reactor vessel. Earlier this week, AECL was provided with a
demonstration of a potential repair technique from a supplier company.
Evaluation of this and other inspection, cleaning and repair options
A full-scale mock-up of a portion of the NRU vessel is currently being
constructed at Chalk River. This mock-up will serve to provide on-site testing
and training of vessel inspection and repair work.
The NRU heavy water leak rate has been reduced to a flow of between 3-4
kg/hr. A small portion of the leakage evaporates and results in a monitored
airborne tritium release through the NRU reactor ventilation system. While
this airborne tritium release remains about 1/1,000 of the regulatory limit,
the action level for tritium release to the atmosphere was exceeded this week
due to the leak.
AECL confirms that there is no threat to workers, the public, the
environment or nuclear safety related to this event. AECL will continue to
provide updates to the CNSC and stakeholders when new information becomes
Further guidance on a return to service date will be provided once a
final decision has been made with respect to the repair technique chosen. AECL
continues to communicate closely with CNSC on NRU outage issues, and CNSC
safety inspectors at Chalk River are monitoring all NRU work.
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For further information:
For further information: Dale Coffin, Director, Corporate
Communications, AECL, 1-866-886-(AECL) 2325