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GLOSSARIES
1. Technical glossary
> UO
2
powder
UO
2
is the symbol for uranium oxide. which comes in powder or pellet form. It is
the constituent component of nuclear fuel. It is also the formula for pitchblende
(natural uranium ore).
> Uraniferous material
Material containing uranium.
> Uranium
Uranium is a radioactive heavy metal. It is a chemical element with the atomic
number 92 and the atomic symbol U, with three radioactive natural isotopes:
238
U
(99.28% fertile),
235
U (0.71% fissile), and a very small quantity of
234
U. Uranium-234,
which comes from the radioactive decay of uranium-238, is not fissile.
> Uranium concentrate (yellowcake)
Magnesium, sodium, ammoniumuranate or uraniumperoxide in solid form resulting
from the mechanical and chemical treatment of uranium ore. This marketable
concentrate contains about 80% uranium.
> Used fuel storage pool
Pools in which used fuel is stored for cooling after it is unloaded from a reactor.
> Used nuclear fuel
Fuel permanently removed from a reactor core after having been irradiated.
> Vitrification
Process used to incorporate concentrated solutions of final radioactive waste (fission
products and minor actinides), which have been chemically separated from the
used fuel, into a glass structure by mixing it with a glass matrix at high temperature.
> Waste packaging
Radioactive waste packaging: operation consisting of packaging waste in a form
suited to radioactive materials containment, enabling its shipment, storage and
final disposal.
p
Very low level radioactive waste such as vinyl or cleaning rags is packaged in
drums, in special “big bags”, or in very large bins. Very low level radioactive
rubble is placed loose inside special big bags.
p
Low level andmedium level waste is first reduced in volume as much as possible,
then packaged in specific ways (immobilized or embedded in a special concrete,
bitumen or resin matrix). The immobilizing or embedding matrix keeps the toxic
and radiotoxic substances contained within the waste package.
p
High level waste is vitrified and poured into stainless steel canisters.
> Wind tower
Used to place the rotor at a sufficient height to reach higher wind velocities and
facilitate its movement; in other words, to extract a much higher energy capacity.
The tower houses certain electrical and electronic components, such as the air
treatment system, the transformer station and the converter.
> Wind turbine
Device that converts kinetic energy from the wind into mechanical energy. This
energy is usually converted into electrical energy.
> Yellowcake (uranium concentrates)
“Cakes” of about 80% uranium concentrates.
> Zircaloy
Type 2 or 4 zirconium-based alloys containing tin, copper, iron and nickel. Other
alloys, to which only niobiumor vanadiumare added, do not bear the name zircaloy.
> Zirconium
Metal chosen for its mechanical strength and corrosion resistance in high-
temperature water, combined with its very low thermal neutron absorption, to make
the alloy used in the cladding of light water reactor fuel elements. Zirconium is highly
resistant to corrosion at high temperature. It is therefore used in the form of an alloy
to fabricate nuclear fuel assemblies, including spacer grids, rods, guide tubes, etc.
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2016 AREVA
REFERENCE DOCUMENT