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A strong partner for both: Fuel assemblies and fuel service

AREVA NP supplies fuel assemblies for pressurized and boiling water reactors. We manufacture all the components – such as cladding tubes, spacers, head and bottom parts – and the nuclear fuel in our own production facilities. By doing so, we ensure the highest quality.

Extensive research and development leads to robust and reliable fuel assembly design. Because it is essential for us that reactor fuel is used even more safely and efficiently.

To complete our range of products, we also offer services and maintenance for fuel assemblies during reactor operation.

In Germany, Advanced Nuclear Fuels GmbH (ANF) produces fuel assemblies for both pressurized and boiling water reactors – for the German and Western European market. About 430 employees work at the two sites Lingen and Karlstein am Main in Germany.

Competence in all fuel assemblies matters


The international fuel assembly design team works intensively on the development of new fuel assemblies for pressurized and boiling water reactors. In this process, we optimize the materials used and the components of a fuel assembly. Furthermore, we continually develop the associated methods and programs. The focus is on safety, reliability and cost-effectiveness.


The optimal behavior of the fuel assemblies during reactor operation is crucial for operators of nuclear power plants. Therefore, careful design is mandatory: This requires extensive expertise and comprehensive research and design work to be carried out. AREVA NP offers both.

Based on analyses, we support the licensing of fuel assemblies for boiling and pressurized water reactors.

State-of-the-art computer programs
In the fuel assembly design process, we employ programs for neutron physical, thermohydraulic and mechanical design and databases (in the picture: three dimensional prognosis of the surface temperature of a cladding tube with the ARCADIA program). The later were developed on the basis of experience gathered over the course of many years.


For utilities, security of delivery counts. Therefore, AREVA NP has own resources and fuel assembly factories in Germany, France, Belgium and the US. And is involved in four joint ventures: in China, Japan and Kazakhstan. This global organization makes us flexible in serving the markets in Europe, the US and Asia using synergies in research and development.

In Germany, we operate two production facilities and one engineering site which manufacture and design fuel assemblies and all associated components and nuclear fuel. They not only produce for German nuclear power plants but also for export.

Inspection and Repair

AREVA NP possesses decade-long experience in the monitoring, inspection and repair of fuel assemblies. The up-to-date equipment is suitable for a variety of fuel assembly designs and reactor buildings.

  • Fuel assembly inspection during outages and in-situ underwater repair of defective fuel rods or fuel assemblies
  • Monitoring of fuel assemblies in pressurized and boiling water reactors
  • Maintenance and repair of fuel assemblies, including remodelling and encapsulation of defective fuel rods etc.
  • Design of special tools for handling fuel assemblies
  • Assistance and training for loading and unloading fuel assemblies

Do you know what a fuel assembly is?

The fuel assemblies are the “heart” of a reactor where nuclear fission creates heat.


The fissile material and the resulting fission products, some of which are radioactive, are safely enclosed in the cladding tubes.


Depending on the type, a fuel assembly contains between 200 and 500 kilograms fuel. It consists of fuel rods which contain the nuclear fuel pellets. The fuel rods are held together by a support structure consisting of guide tubes, spacers, top and bottom part.


On average, the fuel assemblies remain inside the reactor for a period of 3 to 4 years. Every 12 to 24 months, between 20 and 50 percent of the fuel assemblies used inside the reactor core are replaced with new fuel assemblies.

Do you know how a fuel assembly is manufactured?

Upon delivery to the fuel assembly factory, the enriched uranium hexafluoride is converted chemically: into uranium dioxide. A powder that is pressed into small pellets.


These pellets are baked in a furnace at 1,700 degrees Celsius to obtain the required mechanical consistency and density. Each of these uranium pellets – a cylinder with a length of 10 to 13 millimeters and a diameter between 8 and 13.5 millimeters – merely weighs 10 grams, but has an energy content that is equivalent to 1,000 kilograms bituminous coal.


Subsequently, around 300 pellets are inserted into tubes, which are approximately 4 meters in length, the so-called cladding tubes. Each tube is sealed with a plug at both ends and welded. We now have a fuel rod.


A support structure combines the fuel rods to bundles, the fuel assemblies.


Between 150 and 265 fuel assemblies are used in pressurized water reactors. In boiling water reactors, the number of fuel assemblies varies between 400 and 800.

Fuel assemblies from Lingen – our contribution towards a power generation with less CO2

In Lingen, Advanced Nuclear Fuels GmbH has been manufacturing fuel assemblies for pressurized and boiling water reactors. For over 40 years! Safety and environmental protection are of top priority.

Fuel solutions: safe and reliable

Nuclear fuel is operated in a highly challenging environment. A large number of high-level scientific and technical skills are needed to achieve flawless design and fabrication quality.

Products and Services
Advanced Nuclear  Fuels GmbH
Press release

Sweden: AREVA to supply fuel assemblies to the Ringhals Nuclear Power Plants 3 and 4


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