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Leading in design and construction of reactors

The glimpse into the future reveals: The world‘s power demand is rising continuously. To meet the huge demand while respecting the climate, we need new safe and economic nuclear power plants.

AREVA NP designs and constructs pressurized and boiling water reactors for nuclear power plants – the two main nuclear reactor systems in use worldwide. Furthermore, we design reactors for naval propulsion and nuclear research facilities.

Up to now, AREVA NP has built 104 pressurized and boiling water reactors for electricity utilities all over the world – running projects in Finland, France, China, Great Britain and Brazil included. We are thus responsible for just over one third of power generation capacity installed in pressurized and boiling water reactors operated worldwide: a proof of AREVA NP's unique expertise in this domain.

Generation III+ reactors

Technology leader: the reactor models EPR, ATMEA1 and KERENA for commercial power generation. They set standards regarding safety.

Research reactors

Reactors are also needed in nuclear medicine or for research and training purposes. AREVA NP offers low-output reactors in this segment.

Do you know what reactor types does exit?

- Light water reactors – pressurized and boiling water reactors. More than three fourths of all nuclear power plants operated worldwide belong to this group.

 - Heavy water reactors

 - Fast breeder reactors

 

They are distinguished by the cooling of the reactor core – wether with water, sodium or helium.

Do you know how a controlled chain reaction works?

Schematic drawing of the fission process

A controlled chain reaction of nuclear fission is induced and maintained in a reactor with the aim to generate heat. This heat is transformed into electrical energy.

 

Only the isotope uranium-235 in the nuclear fuel is fissile when it is "bombarded" with neutrons. A neutron is absorbed by a uranium-235 nucleus splitting it into two to three nucleus fragments. This fission releases energy in the form of heat and two to three neutrons, which in turn split other uranium-235 nuclei ... Once set in motion, the chain reaction in reactors is consequently self-sustaining.

 

The nuclear fuel is available in the form of small pellets. These pellets are stacked inside thin-walled, gastight sealed tubes, the so-called fuel rods. These rods are then bundled together to form a fuel assembly. The fuel assemblies are located inside the reactor pressure vessel, a steel vessel filled with water, where they form the reactor core – the source of energy of the nuclear power plant.

 

To vary the output of a reactor, the intensity of the chain reaction is regulated. This is accomplished by means of neutron-absorbing control rods. These control rods are inserted into the reactor core in varying distances, changing the number of absorbed neutrons and thereby regulating the reactor output. In the event of an abnormal situation, the control rods automatically move (in boiling water reactors) or are dropped (in pressurized water reactors) completely into the core, thereby inhibiting the chain reaction.

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Video

Operation of a pressurized water reactor

Video

Safety profile of the EPR reactor

EPR reactor: six barriers prevent the release of radioactive materials
AREVA GmbH