M. Brown - 2008 Jan 14: This document provides definitions and examples related to reliability, and shows the calculations used to quantify the reliability CANDU reactors. CANDU reactors have the highest capacity factor of all the sources used to generate electricity in Ontario. The managers of the electricity distribution grid must obtain sufficient electrical power at all times, matching various sources with the fluctuating demand. Opponents of nuclear reactors have claimed that Ontario's reactors are not reliable enough. These claims are contradicted by the records of reactor output.