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GLOSSARIES
1. Technical glossary
> Storage
Temporary storage of radioactive materials or waste in a facility that is specifically
designed for that purpose, pending their removal.
> STUK
Counterpart to the Autorité de sûreté nucléaire (French nuclear safety authority ASN).
Field of jurisdiction: nuclear safety and radiation protection.
> SWU (separative work unit)
An enrichment plant’s production is expressed in SWU. This unit is proportionate
to the quantity of uranium processed and is a measure of the work required to
separate the fissile isotope.
> TDG order
French modal order of May 29, 2009 on the transport of dangerous goods (“TDG
order”).
The order applies to the national or international carriage of dangerous goods
by road, rail and inland navigation in France, including loading and unloading
operations, intermodal transfers and halts required by transportation circumstances.
The order stems from international and European Community laws and applies in
particular to the carriage of radioactive materials (class 7 carriage).
> Ten-year inspection
Every ten years, nuclear reactors are inspected thoroughly, including a detailed
inspection of its principal components: the reactor vessel, the primary cooling
system, and the reactor containment.
> Thermonuclear fusion
The energy from the stars, such as the sun, is produced by the nuclear process
of fusion of light atoms, such as hydrogen. Fusion is the opposite of fission, for it
corresponds to the merging (rather than the splitting) of atomic nuclei.
> Thorium
Natural radioelement (232 isotope) that can produce the fissile uranium isotope of
uranium,
233
U, through neutron capture.
> Tokamak
Acronym from the Russian expression
toroidalnaya kamera magnitaya katushka
,
whichmeans “toroidal chamber andmagnetic coil”. The International Thermonuclear
Experimental Reactor (ITER) aims to study hot plasmas in this configuration.
> Torrefaction
Torrefaction (or depolymerization) of biomass is a mild form of thermo-chemical
treatment (from200 to 320 ) used to eliminate water and change part of the organic
material used in biomass to break down its fibers. During the torrefaction process,
light organics are removed and the structure of the biomass is depolymerized and
changed, causing the fibers to break. Torrefied biomass, also called biocoal, is a
high-quality solid fuel that is ideal for certain types of industrial applications, both
general and specific, including electricity generation, heat production, cogeneration
and central heating. This new fuel opens up newpossibilities for renewable energies.
> Trading
Commercial transactions in the natural uranium market not directly connected to
the group’s mining operations, in the form of the purchase, sale, exchange, lease
or loan of uranium.
> Transportation emergency response and management plan
Instantly activated in the event of a transportation incident involving radioactive
materials. It covers the phases of alert, situational analysis and response in the
field following an incident or accident involving the transportation of radioactive
materials. It makes available specialized human resources and special equipment
to the competent authorities. The entire plan is tested on the national scale once a
year on average with the leading players, and in particular the competent authorities.
> Transuranic elements
Chemical elements in which the nucleus contains more protons than uranium,
which has 92. The first transuranic elements are, in increasing order, neptunium,
plutonium, americium and curium.
> Tritium
Isotope of hydrogen whose nucleus consists of one proton and two neutrons. It
emits beta rays and is present in the natural state in the air and in effluents from light
water reactors. Tritium and deuterium are the two reagents chosen for controlled
fusion projects.
> Turbine
Device used to convert the energy contained in a fluid (water, steam, gas, etc.) into
a rotary motion. The turbine is also used to drive the rotation of a current generator
in units that generate electrical energy.
> UF
4
Uranium tetrafluoride.
> UF
6
Uranium hexafluoride.
> Unit, nuclear unit
Unit for power generation consisting of a nuclear steam supply system, including
the reactor, and a turbogenerator. Nuclear power plants generally have several
units on one site.
> Units of measurement
p
Becquerel (Bq): international unit of measurement of activity (1 Bq = one atomic
particle disintegration per second). The becquerel is a very small unit. Previously,
nuclear activity was measured in Curies (one curie = 37,000,000,000 Bq,
corresponding to the activity of one gram of natural radium).
p
Sievert (Sv): legal unit of dose equivalent, used to determine the biological effects
produced by a given absorbed dose on a living organism. Dose equivalent is
not a measurable physical quantity; rather, it is calculated. It is determined by
multiplying the absorbed dose (expressed in grays, where 1 gray = 1 joule per kg)
by two coefficient factors which depend on the type of radiation and the type
of tissue affected. The millisievert (mSv), which represents a thousandth of a
sievert, and the microsievert (μSv), which represents a millionth of a sievert, are
used for low doses. By way of example, the average annual natural radioactivity
per person in France is 2.4 mSv, a chest x-ray represents about 0.1 mSv, and a
round trip by air between Paris and New York is from 50 to 150 μSv.
2016 AREVA
REFERENCE DOCUMENT
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