372 / 386
GLOSSARIES
1. Technical glossary
> ASN (
Autorité de sûreté nucléaire
)
The ASN is an independent administrative authority charged by the French State
to regulate nuclear safety and radiation protection and to keep the public informed
of these subjects. It reports to the French Parliament.
> Assembly, fuel assembly
A monolithic assembly of nuclear fuel rods filled with fuel pellets (in the case of
MOX fuel, made of a mixture of uranium and plutonium oxides). Depending on
its generating capacity (e.g. from 900 MWe to 1,600 MWe), the reactor core of a
pressurized water reactor (PWR) contains from 150 to 240 fuel assemblies. The
dimensions of the assemblies and the quantity of fissile material they contain are
a function of the reactor type.
> Atom
Component of matter consisting of a nucleus containing positively charged or
neutral particles (protons and neutrons), which account for almost all of its mass,
around which negatively charged particles (electrons) spin.
> Becquerel (Bq)
See unit of measurement.
> Biomass
Any organic matter of plant, animal or human origin. Biomass can be classified by
origin, chemical composition or its use for energy. When used to produce energy,
solid biomass from forestry, agriculture and agri-food activities, wet biomass such
as waste, effluents, or treatment plant sludge, and other biomass may be chosen,
in addition to energy crops, which are plants cultivated exclusively for energy
production (algae, corn silage, soybeans, etc.).
> Biomass burner
Component of a biomass power plant in which a solid biomass fuel is burned. The
heat released by combustion is used to raise the temperature and/or pressure of a
heat transfer fluid (typically water) for different types of applications.
> Biomass power plant
Typically, a power plant that generates heat and/or electricity from the combustion
of a solid biomass fuel. Its main components are a fuel handling system including
a storage silo, a system to feed the fuel into the burner, the burner itself (including
the fixed or fluidized bed combustion technology and the dog leg system), a steam
turbine-generator combination, and combustion fumes to reduce the emission of
pollutants to the atmosphere.
> Burnup
Assessment of fuel depletion expressed in gigawatt days per metric ton of heavy
metal (GWd/MTHM). This is the unit of measurement for the thermal energy
supplied by the fuel during its irradiation in the reactor. The term “heavy metal”
designates isotopes starting with uranium and up.
> BWR (boiling water reactor)
Nuclear reactor moderated and cooled by light water which is brought to the boiling
point in the reactor core under normal operating conditions.
> Carbon credits
Units allocated to companies leading projects that reduce greenhouse gas
emissions. The credits can be sold to help finance the projects. Usually calculated
in metric tons of CO
2
equivalent, one carbon credit represents a reduction of one
metric ton of CO
2
. It can be used to compensate for greenhouse gas emissions in
any sector: industrial, transportation or residential.
Countries that have signed the Kyoto Protocol use carbon credits to achieve their
greenhouse gas emissions reduction objectives.
> Cask
Structure designed to safely contain the radioactive material transported. It may
include a variety of special materials, such as radiation-absorbing materials or
thermal insulation materials, as well as service equipment, impact limiters, and
devices for handling and securing.
> CEA (
Commissariat à l’énergie atomique et aux énergies
alternatives
)
A public scientific, technical and industrial research organization that is in a category
by itself in France.
In addition to its fundamental research activities in materials and life sciences, the
CEA is active in three major fields: defense and global security, energies that do not
emit greenhouse gases, and technologies for information and health. It is tasked
with promoting the use of nuclear power for scientific and industrial purposes and
for national defense.
> Centrifugation
Uranium enrichment process that takes advantage of the difference in mass
between the 235 and 238 isotopes of uranium, whereby a gaseous mixture of
isotopes is spun at high speed and the centrifugal force is used to modify the
composition of the mixture. Ultracentrifugation currently has the highest efficiency
of the enrichment processes.
> Chemical element
Category of atoms that all have the same number of protons in their nucleus.
> Cladding
Sealed metal tube constituting the outside of the fuel rod in which the nuclear fuel
is inserted to protect it from corrosion by the coolant and prevent the dispersion
of fission products. Cladding constitutes the primary containment barrier. For
pressurized water reactor fuel, the cladding is made of zircaloy, an alloy of zirconium.
> Cleanup
All technical operations to eliminate the risks related to industrial operations and
radioactivity in a nuclear facility, consisting of decontaminating the structures,
fixtures, floors and walls of the buildings.
> CLIS (
Comité Local d’Information et de Suivi
)
Instituted near the Bure underground research laboratory in France, it is tasked with
a general mission of follow-up, information and consultation on radioactive waste
management, and in particular on the disposal of such waste in deep geological
formations.
> Cogeneration
Combined production of heat and electricity in the same power plant. One or
more fuels may be used, including biomass, biogas (methane), natural gas, coal
and fuel oil.
372
2016 AREVA
REFERENCE DOCUMENT