n. & adj. — Industry, proprietary
a type of nuclear power reactor.
Type: 1. Origin — The first CANDU reactor went into operation in 1962. These reactors, invented and built in Canada, have been sold world-wide (see Canadian Nuclear Association reference). The abbreviation is most commonly used in Canada (see Chart 1).
See also Gage-5, s.v. "CANDU", and ITP Nelson, s.v. "CANDU reactor".
Images:

Image 1: Two CANDU reactors at the Qinshan Nuclear Power Plant in China. Source: Wikimedia Commons. Photo: Atomic Energy of Canada Limited 
Chart 1: Internet Domain Search, 23 Aug. 2012