High levels of radioactive isotope led to discovery of Lepreau leak

N.B. Power says 200 litres of heavy water recovered inside reactor building

Erica Butler· CBC News · Sep 22, 2026, https://www.cbc.ca/news/canada/new-brunswick/high-levels-radioactive-isotopes-disovery-lepreau-leak-9.7354212

N.B. Power said it has collected about 200 litres of heavy water from a leak at the Point Lepreau Nuclear Generating Station earlier this month, which the utility initially characterized as “small.”

In emails this week, the utility has shared more details about the leak, which CBC News first reported on Sept. 15.

The utility first became aware of a problem inside its reactor building on Sept. 10, when its monitoring system identified elevated levels of tritium.

Tritium is a radioactive isotope that occurs in the heavy water used to transfer heat from nuclear reactors.

The higher than normal readings “triggered an investigation to determine the cause,” said N.B. Power spokesperson Tracey Stephenson on Tuesday afternoon.

Lepreau was shut down on Sept. 11, and a heavy water leak from a 3/8ths-inch instrumentation line was confirmed on Sept. 14, said Stephenson.

The utility reiterated this week that the leak caused “no impact or safety risk to the public, staff or the environment.”

When the elevated tritium levels were detected, there were “no employees in the immediate vicinity,” said Stephenson because “that specific area is not accessible when the Station is online.”

That means there were no “unplanned or unexpected employee exposures associated with the leak,” said Stephenson.

The staff who investigated the problem did so following radiation safety procedures, including using specialized monitoring and personal protective equipment, she said.

Most of the heavy water leaked as vapour, said Stephenson, and was “recovered and collected” through station processes.

“The material remained contained within the reactor building at all times and there was no risk to workers, the public or the environment,” she said.

Timing of information release

It’s taken over a week for N.B. Power to release details about the heavy water leak.

A Sept. 14 press release announcing the Lepreau shutdown made no mention of a leak. It said the station was taken offline to “repair a small instrumentation line inside the reactor building.”

In an interview with CBC News the next day, deputy site vice-president Joel Armstrong acknowledged there had been a heavy water leak but said it was too early to comment on how much was spilled.

Kathleen Duguay, N.B. Power’s head of community affairs and nuclear regulatory protocol, spoke to Radio-Canada on Sept. 16 and characterized the leak as small. She said, speaking French, “It’s just a few drops coming out of the instrumentation line.”

Stephenson said Tuesday that the vapour state of most of the leak might account for the difference in “what might be expected from a liquid leak alone.”

‘Lack of information’

Energy researcher Susan O’Donnell said she is concerned about the “lack of information” initially disclosed by N.B. Power about the leak, starting with a Sept. 14 news release that did not share any details about radioactive heavy water.

“Why did they not just say this was radioactive material that leaked, this is how much material was leaked, this is the volume of radioactivity in the material?” asked O’Donnell.

“’X number of workers were cleaning it up, or were exposed … but hey, everyone’s OK. They’ve all been checked. There’s no problem. We’re looking into it.’

“Instead, it’s just this sort of vague information that doesn’t give anyone who’s interested in it all the facts that they need,” she said.

O’Donnell said N.B. Power should be “super transparent” about any release of radioactive material or risk a “lack of trust” with the public.

“People just get really suspicious. Like, what’s going on there? What are they not telling us?”

Too early to say what caused leak

O’Donnell said she has other concerns regarding the leak, including the potential risk to workers and the cause of the leak itself.

O’Donnell said she’s concerned about the age and tritium levels of the heavy water being used in the closed circulation system at Lepreau and whether it may have been a contributing factor to the leak.

Armstrong said on Sept. 16 that N.B. Power had started the process to determine the cause of the leak, but any conclusions would be “premature.”

“Our focus right now is making sure that we facilitate the repair … in a safe manner,” said Armstrong.

N.B. Power did not release the number of workers involved, but the utility said that staff in the area of the leak were working under strict protocols.

The Canadian Nuclear Safety Commission said via email that it has site inspectors stationed at Point Lepreau, and it was made aware of the leak on Sept. 10.

“We are engaged with N.B. Power as it conducts a thorough assessment of the incident and undertakes the necessary repair activities,” said the commission.

It also noted that “no workers have been reported to have received radiation doses above regulatory limits.”