| Systems services |
Systems services are services provided to users (consumers or electricity producers) through the joint action of the electricity transmission network operator RTE and the producers. They are intended to regulate frequency and voltage in order to maintain the balance between electric consumption and generation at all times. They are created by RTE from elementary contributions from producers, i.e. primary and secondary reserves provided to RTE. RTE remunerates the producers for these auxiliary services before reinvoicing these services via the tariff to use the network under the rules defined by the Union for the Coordination of Transmission of Electricity (UCTE). |
| Smart city |
The smart city is a new urban development concept aiming at improving the quality of life of city dwellers by making the city more adaptive and efficient, using new technologies based on an object and service ecosystem. The scope of this new way of managing cities includes: public infrastructure (buildings, street furniture, home automation, etc.), networks (water, electricity, gas, telecoms); transport (public transport, intelligent roads and cars, carpooling, so-called soft mobility – by bike, on foot, etc.); e-services and e-administrations. |
| Smart charging |
Smart charging is an umbrella term for all technologies aimed at optimising the charging or discharging of an electric vehicle through efficient, flexible and economical management of the vehicle’s recharging power. |
| SMR |
SMRs (Small Modular Reactors), petits réacteurs modulables in French, are small-scale power plants with one or more reactors with a unit power of less than 300MWe. This small power allows for the reduction of certain systems, standardisation of design and thus a reduction in the duration of construction sites in order to improve their competitiveness. |
| STEP |
Pumped-storage hydropower plant. Power plant with two tanks, an upper and a lower one, connected by pumps that allow the water to be pumped up once turbined and located in the lower tank, towards the upper tank. |
| Storage |
Storage consists in placing packages of radioactive waste in a facility, ensuring their long-term management, i.e., under safe conditions allowing for long-term risk control. |
| Nuclear safety |
Nuclear safety includes all of the technical, organisational and human measures which are intended to prevent accident risks and to limit the effects of an accident, and which are taken at every stage of the nuclear power plant lifecycle (from design to operation and finally to decommissioning). |
| European Green Taxonomy |
Commission delegated regulation (EU) 2021/2139 of 4 June 2021 supplementing regulation (EU) 2020/852 of the European Parliament and of the Council with the technical review criteria for determining under which conditions an economic activity can be considered to contribute substantially to climate change mitigation or adaptation and whether that economic activity does not cause significant harm to any of the other environmental objectives. |
| Therms (th) |
One therm (th) is equivalent to 1,163kWh or 4,186 million joules. |
| Nuclear unit |
Electrical generation unit consisting of a nuclear boiler and a turbo-alternator generator. A nuclear unit essentially consists of its reactor type and the power of its turbo-alternator generator. EDF nuclear plants include two or four units, and occasionally six. |
| Uranium |
In its natural state, uranium is a mix containing three main isotopes (elements whose atoms have the same number of electrons and protons, thus the same chemical properties, but a different number of neutrons):
- uranium 238, 99.3% fertile;
- uranium 235, 0.7% fissile;
- uranium 234.
Uranium 235 is the only natural fissile isotope, a quality which justifies its use as an energy source. |
| Enriched uranium |
Uranium, whose isotope 235 content, the only fissile material, has been increased from its low natural level (0.7%) to approximately 4% in order to be used as pressurised water reactor fuel. |
| ERU (enriched reprocessed uranium) |
To be used in a reactor, reprocessed uranium (RepU), even if containing more fissile uranium than in its natural state, must be further enriched. It is therefore called enriched reprocessed uranium (ERU). |
| RepU (reprocessed uranium) |
Reprocessed uranium (“RepU”), uranium derived from spent fuel reprocessing, differs from natural uranium as it contains slightly more uranium 235 and other uranium isotopes. It is recyclable and RepU fuel assembly refuelling is ordinaryly used in reactors. |
| Vitrification |
Process of immobilisation in a glass structure of concentrated solutions of high-level radioactive waste by mixing at high temperature with glass paste. |
| Non-interconnected zones |
Zones in France which are not connected (by power lines) to metropolitan France (Corsica and overseas departments). |
