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ATMEA1 reactor: 1,100 MWe pressurized water reactor

3D representation of the REP ATEMA1 reactor

The ATMEA1 reactor is a 1100 MWe pressurized water reactor. It is intended for all types of networks, especially mid-power electrical networks.

ATMEA1 is a generation III+ model. It therefore has properties similar to those of the EPR™ reactor in terms of safety and environmental impact. It offers great operational flexibility and a high degree of competitiveness because of its reduced electricity production costs. It also offers great operational flexibility.

The ATMEA1 reactor was designed and developed jointly by Mitsubishi Heavy Industries and AREVA, in their joint company ATMEA. It benefits from the skill and experience offered by both companies, which together are credited with launching nearly 130 power plants worldwide over the last fifty years.

Safety, Competitiveness, Flexibility

3D mesh representation of the ATMEA1™ reactor


  • Unrivalled safety level:  
    • Resistance to plane crashes
    • Resistance to seismic shock 0.3 g or higher
    • Triple redundancy in safety features backed-up by a safeguard system
    • Severe accident management with long-term integrity of the reactor containment thanks to a special compartment to isolate the core during a meltdown
  • Active and passive safety systems:
    The ATMEA1 reactor combines active and passive systems to increase safety and ensure improved process control.



  • Maximized electric production:   
    • Through reliable components, proven technology
    • Thanks to shorter unit outages, resulting in an increased level of availability
  • Environmental protection:  Reduction in fuel consumption per kWh and production of long-life waste products (-15%)  thanks to a higher thermal efficiency.
  • Innovation for performance.
    Two new features of the EPR reactor included in the ATMEA1 model contribute to its performance:
    • Steam generators with an axial economizer provide increased steam pressure and noticeably increase the reactor's thermal efficiency. These components were developed and tested in the N4-type reactor.
    • A neutron reflector, surrounding the core, reduces fuel consumption by limiting neutron leakage. It also increases the lifespan of the reactor pressure vessel by limiting its irradiation and embrittlement.

Service life: 60 years



A varied choice of fuels. An ATMEA1 power plant can operate with uranium enriched up to 5%, reprocessed uranium or MOX fuel (in variable proportions according to customer needs and up to 100%).

Maximized electric production:   

  • Reduction in fuel consumption compared with currently operating pressurized water reactors
  • 12-24 month operation cycles with the possibility of functioning 100% on MOX
  • Load following
  • Maintenance during operation 

Integrated range of services

With this offer, AREVA provides its customers with a global maintenance approach for power plants and/or component lifecycle management.

The range of reactors

AREVA is responding to the needs of its clients by enlarging its power range with third generation models.