Someday, this could all be ours

The latest from Chalk River:

Radioactive water has stopped leaking from the nuclear reactor at Chalk River, Ont., ending two months of low-level radiation seeping into the atmosphere near Ottawa.

Workers with Atomic Energy of Canada Ltd. recently completed draining the reactor's 65,000-litre vessel and are now preparing to dispatch a remote-controlled ultra-sonic probe deep into the disabled machine to inspect the site of a pinhole leak of tritium-laced heavy water that began May 14.

What it reveals will help determine what is expected to be a delicate, complex and potentially costly repair strategy.

Most of the leaking water was slowly captured and stored in special drums and is to be reused when the National Research Universal reactor restarts. But about 20% evaporated and was drawn into the building's ventilation system. To prevent a dangerous buildup of tritium inside the NRU building, the airborne tritium was steadily released into the atmosphere as the leak progressed.

The quantity going into the surrounding air, some of which then fell on land and into the Ottawa River, was well within current maximum health limits. Still, those limits were publicly questioned in June by the federal nuclear safety commissioner, echoing a long-running debate over what constitutes safe exposure to cancer-causing tritium, especially in drinking water.