NB Power officials say a radiation alert at the Point Lepreau nuclear generating station Tuesday was caused by a small spill in the reactor building.
The station has been shut down for nearly four years for refurbishment and the utility is refilling equipment with heavy water as it gets ready to restart, spokeswoman Kathleen Duguay stated in an email.
"Preliminary information indicates that a small spill occurred within the reactor building," she said. The heavy water is radioactive.
Although an initial statement from Duguay indicated the event did not pose "any risk" to the public or environment, an updated statement said it "does not pose significant impact to the public or environment."
'We have highly qualified and trained staff in the area of spill response.'—Kathleen Duguay, NB Power
The reactor building was evacuated about 4 p.m., immediately after the alert was initiated, according to procedures, said Duguay.
Radiation monitoring equipment is designed to alarm immediately in response to any radiation event, she said.
Alarms from the sensitive detectors have been common in the last two weeks, as the reactor equipment is being refilled, Duguay said.
"When we transfer heavy water to the moderator system, it is not out of the ordinary for our radiation monitoring equipment to record any presence of tritium. This is contained inside the reactor building."
This is the first time the reactor building was evacuated, however, Duguay said.
"We plan for various contingencies and have appropriate plans in place to address these potential events should they arise," she said. "We have highly qualified and trained staff in the area of spill response."
Licence up for renewal
The Canadian Nuclear Safety Commission is currently considering NB Power's application for a new five-year operating licence for Point Lepreau.
Earlier this month, several groups attended public hearings to oppose the licence. The New Brunswick Conservation Council contends the plant can't be licensed because it doesn't meet new earthquake standards adopted for nuclear stations after the disaster in Japan in March.
Point Lepreau, Atlantic Canada's only nuclear reactor, is undergoing a $1.4-billion refurbishment.
It was originally expected to be back generating power by September 2009, but Atomic Energy of Canada Ltd., ran into problems.
Several of the 380 calandria tubes that were installed were leaking and had to be removed. The problem tubes have since been replaced and tested.
The tubes are approximately six metres long and 13 centimetres in diameter, and will contain the reactor's fuel channels and fuel bundles.
Workers are preparing for the fuel channel installation activities, which are expected to be completed this month.
The next step will include the installation of pressure tubes, spacers, end fittings and positioning assemblies as well as bellows welding.
It is estimated that NB Power spends $1 million a day to purchase replacement fuel for each day the nuclear reactor is delayed.