Staff working for Atomic Energy of Canada Ltd. lost a metal part they removed from a reactor at the Bruce nuclear power station in April, and didn't tell anyone until an employee from the station found it in June when it triggered the alarm on his radiation monitor.
Bruce Power immediately notified the Canadian Nuclear Safety Commission that one of its workers received a radiation dose, as is required under safety rules.
Critics say the incident highlights a serious loophole in Canada's nuclear regulations. AECL is a contractor at the site, refurbishing the aging Bruce 1 station, and isn't immediately required to divulge when it loses track of highly radioactive materials pulled from reactors.
The missing part - a piece of metal about 10 centimetres in size - came to light only because a worker inadvertently received a radiation dose, which is considered such a serious incident that it must be reported to regulators either "immediately" or by the end of the next business day.
Bruce Power was miffed by the incident, and has informed AECL that, from now on, it wants to be informed if radioactive material goes missing.
"We do expect that if material is unaccounted for, we want to be told about it," said Steve Cannon, a Bruce spokesman. "We talked to AECL about that. ... They understand that it's important."
The missing piece was emitting high amounts of radiation, and would have given any worker holding it the maximum yearly allowed dose of this form of energy - feared because it can cause cancer - in only a few minutes.
But workers in the plant didn't come near the dangerous part because they handled it using remote-control devices, and the employee who made the discovery got only a chest X-ray type dose by quickly backing away.
The regulatory report filed by Bruce on June 24 indicates that AECL "became aware on April 23" that the piece was missing, but "they failed to notify" the station's radiation protection department. "The increased hazard would have existed from that time," it said.
Greenpeace nuclear critic Shawn-Patrick Stensil said "it's amazing that you can lose a major radioactive component and not have an obligation to report it."
He contended that the incident, which he said "shows a culture of secrecy," will undermine AECL as it tries to sell new reactors in Ontario, where the government wants new atomic power plants built to meet future electricity needs.
Dale Coffin, a spokesman for Crown-owned AECL, played down the events, saying no one was harmed over the two-month period that the piece was missing because workers weren't in the area. Once it was found, the location, in the reactor vault, was safely cordoned off. "There is no requirement on our behalf to notify the CNSC because nobody was in there working," Mr. Coffin said.
The Bruce nuclear station is located on Lake Huron near Kincardine, Ont..
The lost piece was known as a calandria tube insert ring. The regulatory report on the incident said no other rings are missing. "It has also been reinforced with staff that should any items that could significantly change radiological hazards be unaccounted for radiation protection staff are to be immediately notified," it said.