Areva - Reference Document 2016

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GLOSSARIES
1. Technical glossary
> Dosimeter
The instrument for measuring radioactive doses received by an individual, or by
certain of that individual’s organs (passive or operational dosimetry), or by the
environment (site dosimetry).
> Ecodesign
Design of a product or an industrial installation that helps reduce the consumption
of natural resources and limit releases likely to impact the environment.
> Electrolyzer
Electrochemical system (energy receptor) in which liquid water is separated into
oxygen and hydrogen by an electrical current that passes between two electrodes.
The ions produced by the oxidation-reduction reactions flow freely from one
electrode to the other. The two electrodes (cathode: reduction reaction; anode:
oxidation reaction) are linked by the electrolyte and the electric current generator.
In the alkaline electrolyzer, the electrolyte is a potash solution that circulates or is
immobilized in a retention matrix; in the membrane electrolyzer, the electrolyte is
in the form of a proton conduction ion exchange membrane.
> End-of-lifecycle operations
All of the regulatory obligations for shutting down and dismantling nuclear facilities
and managing radioactive waste.
> Enriched uranium, depleted uranium
Before it is used to fabricate fuel elements for reactor systems moderated and
cooled with ordinary water, natural uranium is enriched in 235U to a concentration
of 3-5%. Natural uranium is used to produce uranium enriched in 235U. The physical
or chemical processes used to enrich uranium also produce uranium that has a
lower concentration of 235U than natural uranium (0.2 to 0.4%): this is known as
depleted uranium.
> Enrichment
Process used to increase the abundance of fissile isotopes in a chemical element.
Naturally occurring uranium essentially consists of 0.7% 235U (fissile isotope) and
99.3% 238U (non-fissile isotope), and must be enriched in 235U for it to be used in
a pressurized water reactor. The proportion of 235U is brought to around 3 to 5%.
> Environmentally regulated facility
Installations and operations “listed in the nomenclature of regulated facilities
that may represent hazards or drawbacks, whether for the convenience of the
surrounding area, for health and safety, for agriculture, for the protection of nature,
the environment and the countryside, or for the preservation of sites andmonuments
as well aspects of an archeological nature.”
> Environmental Management System (EMS)
Part of the overall management system, which includes the organizational structure,
planning activities, responsibilities, practices, procedures, processes and resources
to develop, implement, carry out and maintain the environmental policy.
> EPR reactor
Generation III+ pressurized water reactor (PWR). It generates 1,650MWe of electric
power and features a greater level of safety than generations II and III reactors and
simplified operations and maintenance. It also has a projected service life of 60
years, compared with an initial service life of about 40 years for the reactors currently
in operation around the world.
> ERU
Fuel made with recycled uranium.
> Euratom
Treaty signed in Rome on March 25, 1957, together with the treaty that founded the
European Economic Community (EEC). It institutes the European Atomic Energy
Community, which aims to establish “the conditions necessary for the formation
and rapid growth of nuclear industries.” Its mission consists of contributing, through
the development of nuclear energy, to the sharing of knowledge, infrastructure and
financing and to ensuring the security of supply within the framework of centralized
control. It brings together the 28 member states of the European Union.
> Exposure
Exposure of an organ or an organism to a source of radiation, characterized by
the dose received.
> Fertile
Said of a nuclide that can be converted into a fissile nuclide via capture of a neutron,
possibly followed by a series of disintegrations.
> Final radioactive waste
Radioactive waste that can no longer be treated, in particular by extracting its
reusable content, under current technical and economic conditions.
> Fissile
Describes a nuclide capable of undergoing fission; the fission of atoms gives rise
to several neutrons.
> Fission
The spontaneous or forced splitting of a heavy nucleus – generally after absorption
of a neutron – into two or three smaller nuclei, or fission products, accompanied by
the emission of neutrons and radiation and the release of a considerable amount
of heat. The substantial energy released is the principle underlying nuclear power
generation.
> Fission products
Fragments of heavy nuclei produced during nuclear fission or the subsequent
radioactive decay of nuclides formed during that process. These fission fragments
and their decay products are collectively referred to as “fission products”.
> Fuel cell
Electrochemical system that converts the chemical energy of the oxidation reaction
of a fuel directly into electrical energy.
In its simplest form, a fuel cell consists of two electrodes (anode and cathode) and
is powered with oxidation-reduction couples likely to achieve a balance with the ions
contained in the electrolyte. The oxidant in the fuel cells is either pure oxygen or the
oxygen in air. The most commonly used reducing agents are gaseous (hydrogen
or methanol), liquid (hydrocarbons or methanol) or solid (zinc, aluminum, etc.).
Unlike accumulators, whose energy is dependent on the active matter incorporated
into the electrodes, a fuel cell uses reactive chemical species froman external source
(outside the cell), and the species formed are constantly eliminated, theoretically
ensuring continuous operation.
374 2016 AREVA REFERENCE DOCUMENT