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2. The EPR™ reactor
The EPR™ (European Pressurized Reactor) is the result of the cooperation between the French Areva and the German Siemens. This reactor belongs to the generation GEN III+ tanks to its innovation regarding safety, security and plant operability.
The EPR™ project relies on the proven technology and experience gained by Areva on the N4 reactor and by Siemens on the KONVOI reactor.
The EPR™ is a four loop light water moderated and cooled reactor with an electrical power output of 1650 MW.
Main innovative features of the EPR™ concept regards plant operability, fuel management, economy and flexibility of operation, thermal efficiency and nuclear safety and security. It is the first nuclear power plant that features a completely digital I&C system, both for normal operation and safety related functions. This choice has come from the needs of increasing manoeuvrability and, at the same time, reducing the risk of human error (according to IAEA requirements no human actions should be needed in the first half hour after an accident has happened).
Safety I&C is based on Areva's TELEPERM XS technology that is the AREVA’s digital I&C platform developed for safety and high-reliability functions in nuclear facilities. It is the first safety-related digital I&C system to receive the approval of the NRC.
Innovations in the neutronics allow saying that the EPR™ is a fuel saving reactor and that can be employed in the closed nuclear fuel cycle required by optimal exploitation of future GEN IV nuclear reactors. In fact the heavy neutron reflector and a larger core reduce the neutronic losses; these solutions extend also the life of structural components facing the core because reduce the neutronic fluence. Moreover the EPR™ is designed to house a 5% enriched natural uranium core or a core made up by MOX or Enriched Reprocessed Uranium (ERU) up to a percentage of 100%.
Economy and flexibility of operation are guaranteed by the cooperation of electrical utility in the EPR™ development from its beginning. In fact thanks to this cooperation it has been possible to capitalize the return of experience of that utility that had already exercised NPPs.
18 Moreover EPR™ is compliant with the EUR (European Utility Requirements) requirements: as an example it is possible to perform load following operation between 60% and 100% of Nominal Power (NP) with a rate of 5% NP/min.
On the thermodynamics side the introduction of an axial economizer in the Steam Generators (SGs) guarantees that the nuclear steam pressure of an EPR™ is higher than the previous reactor generation: this allows reaching a 37% thermal efficiency against the “classic” 33% of older NPPs. The increase in efficiency has also positive effects on the fuel consumption: 15% of natural uranium is saved for MWh produced compared to other 1000 MWe reactor.
Safety and security have played a renewed role in the EPR™ design. In fact severe accidents (core melt) have been considered to embed new safety features and safety standards have been risen by the introduction of four times redundant and diversified engineered safety features.
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