The CANDU reactor is a Canadian-invented, pressurized heavy
water reactor developed initially in the late 1950s and 1960s by
a partnership between Atomic Energy of Canada Limited (AECL),
the Hydro-Electric Power Commission of Ontario (now known as
Ontario Power Generation), Canadian General Electric (now known
as GE Canada), as well as several private industry participants.
The acronym "CANDU", a registered trademark of Atomic Energy of
Canada Limited, stands for "CANada Deuterium Uranium". This is a
reference to its deuterium-oxide (heavy water) moderator and its
use of uranium fuel (originally, natural uranium). All current
power reactors in Canada are of the CANDU type. Canada markets
this power reactor abroad. The CANDU reactor is conceptually
similar to most light water reactors, although it differs in the
details. Fission reactions in the nuclear reactor core heat a
fluid, in this case heavy water (see below). This coolant is
kept under high pressure to raise its boiling point and avoid
significant stea