The CNSC policy document, for the record, is P-242. It's only a short document of about four or five pages. It was written by the CNSC upon discussions during the amendments to the Atomic Energy Control Regulations. The desire here was to ensure that you make decisions about safety in light of the fact that it is not just in isolation but in a broader consideration of the kinds of costs that it could impose upon either the licensee or society in general.
On February 7th, 2008. See this statement in context.