If the worst comes to pass

By Graeme McNaughton/The Oshawa Express

With the upcoming distribution of potassium iodine tablets, Durham residents may be wondering what will happen in the event of a nuclear emergency.

The province already has legislation in place that guides local municipalities what to do in the event of a worst-case scenario.

The local implementation of the Provincial Nuclear Emergency Response Plan falls to the Durham Emergency Management Office (DEMO).

“Under the PNERP, local municipalities like ours that have nuclear generating stations, we’re required to have a response plan and they must confirm to the provincial plan. So the response actions and the decisions during a response are really made at the provincial level and locally…we implement those,” says Warren Leonard, DEMO’s director.

The level of the response, Leonard says, depends on the severity of the incident and how the province chooses to respond.

“We might take protective actions, for example, like sheltering. People in the area might be asked to shelter in place, if that’s the decision, if that’s the best action to take, and we’d get that message out to them through our usual mechanisms,” xxx says of the warning system, which would see information broadcasted on local radio stations and on television, as well as through an automated phone dialing system.

Residents may also be asked to take their potassium iodine pills, set to be distributed next month.

In the worst-case scenario, residents will be advised to evacuate.

DEMO tests its emergency systems twice a year, notifying residents within a 10-kilometre zone of the region’s two nuclear generating stations what is going on.

On top of that, there are also sirens within a three-kilometre zone of the plants that are also tested twice a year.

Past incidents

There have been several incidents at the Pickering station, the older of Durham’s two nuclear plants.

On Aug. 1, 1983, a pressure tube in one of the plant’s reactors developed a split, leading to it to being shut down. The cause of the split was found to be the mislocation of spacer springs, which allowed the pressure tube to sag inside of the calandria tube, leading to more hydrogen in cooler areas, thus making the tube more brittle.

As a result, all of the pressure tubes in Pickering’s A reactors – where the incident occurred – were replaced.

On Dec. 10, 1994, an accident dubbed the most serious in Canadian history by the Standing Senate Committee on Energy, Environment and Natural Resources occurred. According to the committee’s 2001 report, a pipe broke in one of the reactors in Pickering A, resulting in a major loss of coolant and the spill of 185 tonnes of heavy water, which is used as a neutron moderator in CANDU reactors such as that at Pickering. The plant’s emergency core cooling system was used to prevent a meltdown.