How do you know Candu is a safer design?

Have they been subjected to the tsunami test?

"The Canadian Nuclear Safety Commission (the regulator)...warn that it may have to order nuclear power plants to run at less than full power indefinitely to compensate for what it deems less-safe conditions..."
"...document says Canada's seven nuclear stations, which all use Candu technology, have a feature known as "positive reactivity feedback," in which their atomic chain reactions automatically speed up if the water pumped into the reactors to cool them leaks, one of the worst accidents possible at a nuclear station. If reactors aren't immediately shut down during this type of incident, positive reactivity leads to a quick snowballing in the pace of nuclear reactions, which in turn could cause potentially damaging overherating."
"...with a large loss of coolant, such overheatng could put the nuclear facilities' containment features- the concrete domes and other protective mechanisms... around reactors which are the last-ditchdefenses to stop the spread of radioactivity into the environment- to a dangerous test.

Document obtained through freedom of information ruling, 2009, posted in Globe and Mail, June 28, 2009, updated July 23, 2009, Reactor Design puts safety of nuclear plants into question.

The plants are old, pipes, etc., are in need of replacement, etc. etc.
So move to Alberta, and take safe refuge in the tar sands!