Glossary - C
Canadian Nuclear
Safety Commission
The Canadian nuclear industry is monitored and
regulated by the Canadian Nuclear Safety Commission (www.nuclearsafety.gc.ca ),
an independent agency of the Government of Canada. The CNSC's name has recently
been changed from the Atomic Energy Control Board.
Source: AECL
Calandria
A calandria in a CANDU
reactor contains the core of the nuclear steam supply system. It is a
large cylindrical vessel, filled with several hundred tonnes of
heavy water. Hundreds of fuel channels run through the calandria,
parallel to the cylindrical axis, each holding 12 or 13
fuel bundles, depending on the design.
Source: AECL
CANDU Reactor
The Canadian nuclear
power reactor design is called CANDU, an acronym for Canada Deuterium
Uranium. CANDU is a unique design that uses natural uranium
fuel and a heavy water moderator. One of the
unique features of CANDU is its ability to refuel while operating at full
power.
Source: AECL
CEAA
Canadian Environmental Assessment Act
Source: NB Power
Chain Reaction
A reaction that initiates its own repetition. In a
fission reaction, free neutrons are
produced which fly off and strike other nuclei,
causing them to split and send off yet more free neutrons. The fission will
continue as long as there are enough free neutrons carrying the right amount of
energy.
Source: AECL
Chernobyl
A town in northern Ukraine where a
nuclear power station was built using one of two Russian power reactor
designs. In April 1986, a severe nuclear accident occurred in one of the four
units, killing 35 people.
Source: AECL
CNSC
Canadian Nuclear Safety Commission
Source: NB Power
Containment
Most reactors are
enclosed in a thick, concrete, domed building, called the containment. In the
event of a release of radioactive material into the reactor building, the
containment traps the emissions and prevents their escape. In a Canadian
CANDU reactor, the core is partly housed in a concrete or steel tank
called the shield tank. This entire structure is enclosed in a second
containment about one metre thick.
Source: AECL
Contamination
Radioactive material deposited or dispersed into
materials or places where it does not belong.
Source: AECL
Control Rod
A rod containing neutron-absorbing
materials, such as boron or cadmium. Control rods are moved in and out of the
core of the reactor to control the rate of the nuclear reaction.
Source: AECL
Coolant
The liquid or gas used to transfer the heat of
nuclear fission to a heat exchanger in which steam is produced to drive
the electrical generator. The cooled liquid or gas is then returned to the
reactor. CANDU reactors use
heavy water as the coolant.
Source: AECL
Critical Mass
The minimum amount of fuel needed in the
core of a nuclear reactor in order
to start a self-sustaining chain reaction.
When a reactor starts up, it is said to "go critical".
Source: AECL
Curie (Ci)
A unit used to measure the rate of
radioactive decay. One curie equals 37 billion disintegrations per
second, or approximately the radioactivity of
one gram of radium.
Source: AECL
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