ALCEN's activities in
Magnetic confinement

Taking advantage of specific technologies and skills developed and mastered by some of its subsidiaries, as well as synergies between these subsidiaries, ALCEN has become a key partner for major magnetic confinement fusion programmes.  
The Group offers innovative solutions and services adapted to the harsh environments of the machines.

Control command

As with all complex machines, fusion reactors require powerful and efficient command & control systems to ensure safe and optimized behaviour of all sub-systems and communication systems. Several hundreds of thousands of signals are often generated and exchanged by them.

Command & control systems are also used to control plasma operations and to collect the huge amount of data that will subsequently be analyzed by the scientists.

ALCEN's expertise

Through its CHAMPALLE subsidiary, ALCEN designs, develops and manufactures control systems compatible with operation in severe environments, especially in the energy domain: Oil&Gas, Nuclear and Solar plants.

With its in-house testing capabilities, CHAMPALLE can provide:

  • Command & control cabinets, command desks, including organizational and human factor-related features, and units with the highest safety and quality standards. 
  • Software is developed using V-models and engineered for all types of PLCs and  Human machine interfaces. 

RCCM-E standards are specifically applied in the nuclear domain and the company has all relevant certifications for the installation, commissioning and maintenance of the supplied equipment.

ALCEN's subsidiaries for Control command

ALCEN's references

Control systems for cryogenic gas transfer

High safety level control systems

Nuclear machinery control systems

Process and control room for electrical power solar plant

Cooling systems

The huge amount of heat generated during the fusion reaction is removed from the vacuum vessel and internal components through high pressure and flow rate cooling channels. In addition to this, some auxiliary systems also need to be cooled: heating systems, cryogenic systems, coil power supplies…

On top of the high quantity of power to be evacuated, up to several hundred MW, the design, manufacture and assembly of the various cooling loops and circuits must comply with severe environmental and nuclear constraints, especially for machines operating with deuterium-tritium plasma.

ALCEN's expertise

  • Thermo-fluidics and thermo-mechanical design
  • Butt welding (BW) and forged fittings
  • Seamless tubes to customer specifications
  • Rolled/welded pipes
  • Flanges
  • Piping accessories according to customer specifications

ALCEN's subsidiaries for Cooling systems

ALCEN's references

Production of cold formed (BW) and machined fittings


Depending on the reactor configuration, cryogenics, at temperatures down to 4K, may be required for proper operation of magnets, pumping systems (cryopumps) and some diagnostics procedures.

Liquid and gaseous helium and nitrogen are produced, stored, recovered and distributed through a complex system which includes refrigerators, tanks, pumps, transfer lines and cold boxes. Such systems must be designed, manufactured and assembled to guarantee efficient and stable operation of the machinery in all scenarios given the high thermal loads.

Within the scope of its activities in the scientific and energy fields, some ALCEN subsidiaries have developed specialised knowledge in cryogenic technology that can be applied to the design and manufacture of specific sub-assemblies.

ALCEN's expertise

  • Design and integration of cryogenic systems
  • Cryostats
  • Valves and motorized connection systems for liquid and gas transfer
  • Thermo-fluidics and thermo-mechanical design

ALCEN's subsidiaries for Cryogenics

ALCEN's references

Assembly of XFEL Cryomodules

Valves and motorized connection systems for cryogenic gas transfer

4K cryostat for the characterization of cryogenic targets

Manufacture of the ITER pre-production cryogenic pump


Control, optimization and analysis of plasma operation requires a wide range of diagnostics systems of various types. Among the most commonly used in fusion reactors are bolometric systems, magnetic diagnostics, microwave diagnostics, neutron diagnostics, optical systems, plasma facing and operational diagnostics and spectroscopic instruments.

These types of diagnostic systems allow for the precise measurement of all plasma parameters (shape, density, temperature, position, current, power…) and also protect the machinery, they must, in most cases, operate under severe conditions in terms of pressure, temperature and radiation.

The design, manufacture and integration of these complex sub-assemblies require skills in specialised domains in which ALCEN has expertise.

ALCEN's expertise

  • Assembly in clean environments
  • Electromagnetism
  • High-precision machining
  • Optics and opto-mechanics
  • Radioactive environments
  • Thermal management
  • Vacuum engineering
  • X-ray components and devices

ALCEN's subsidiaries for Diagnostics

ALCEN's references

X-Ray imaging system prototype

Design, manufacture and on-site installation of plasma diagnostics for the LMJ demonstrator

Apollo system for surveillance in nuclear environment

Design and manufacturing of X-Ray components

Heating & Current drive

In order to reach the plasma state and allow the fusion reaction to occur, the gas inside the vacuum chamber must reach temperatures in excess of 100 million °C.

The required input heating power is provided by two types of external sources: neutral beam injection and electromagnetic wave sources.

Through some of its subsidiaries, ALCEN is specialised in the key technologies necessary for the design and manufacture of these types of sources and has demonstrated its capabilities in several major specialised programmes.

ALCEN's expertise

  • Assembly: welding, brazing, high isostatic pressure (HIP) bonding
  • High-precision machining
  • Materials: stainless steel, copper and alloys, beryllium, ceramics…
  • Thermal and thermo-mechanical management
  • Electromagnetism
  • High voltage
  • Vacuum engineering

ALCEN's subsidiaries for Heating & Current drive

ALCEN's references

Manufacturing of the Tore Supra ICRH Faraday screen

ITER beryllium Faraday screen prototype

High frequency RF windows

Design optimization of the neutral beam injection system ion source

Hot cells

Even if the fusion reaction does not produce radioactive products, the components of the vacuum vessel may be activated by high energy neutrons. Furthermore, depending on the machine configuration and the fuel used, materials can be contaminated by dust (beryllium, tungsten) and tritium.

Hot cells are thus required to enable maintenance, decommissioning, and in some cases detritiation, of the exposed sub-assemblies, through remote-handling operations.

ALCEN's expertise

Within the framework of its activities in the nuclear domain, ALCEN has developed recognized expertise in the design and manufacture of hot cell key components (remote-handling and robotic systems, glove boxes…) and the supply of turnkey hot cells.

ALCEN's subsidiaries for Hot cells

ALCEN's references

Design and Manufacturing of LMJ Glove boxes

Hotcell for an electromechanical press

Nuclear fuel rod cutting bench

Design and Engineering of the Astrid hot cell

In-vessel components

Depending on their structure and location, In-Vessel Components have various functions. 

Covering the surface of the vessel, with the exception of dedicated passages for diagnostics and heating systems, the blanket protects the vessel and magnets against high heat and neutron fluxes.

Located at the bottom of the vessel, the diverter enables heat and ashes to be removed while minimizing plasma contamination.

Both usually include assemblies made from various materials: stainless steel is used for the support structure, copper or copper alloys allow for heat transfer and the plasma-facing components are usually made from exotic materials such as beryllium, CFC or tungsten, based on their exceptional physical properties.

Depending on the reactor characteristics, In-Vessel Components may be actively cooled using high pressure and flow-rate water circuits.

ALCEN has unique expertise in techniques for manufacturing and assembling these types of critical components, as it has demonstrated in major fusion programmes.

ALCEN's expertise

  • Assembly: welding, brazing, high isostatic pressure (HIP) bonding
  • High-precision machining of medium to large size parts
  • Materials: Beryllium, Copper and associated alloys, Stainless steel, Tungsten…
  • Thermal and thermo-mechanical management

ALCEN's subsidiaries for In-vessel components

ALCEN's references

Manufacturing and assembly of the ITER first wall panel prototype

Manufacturing of the ITER divertor inner vertical target prototype

Manufacturing of Feasibility Mock-Ups and Development of Welding procedures


Generation, confinement, shaping and control of the plasma is achieved by adding various magnetic field configurations, forming lines along which the particles circulate.

These types of fields are generated by normal or superconducting magnets, depending on the required strength.

Even if not directly involved in magnetism, ALCEN has at its disposal several technologies which are essential to the development and manufacture of fusion reactor magnetic systems.

ALCEN's expertise

  • Command & control systems
  • Cryogenic systems
  • Development and manufacture of specific assembly and test tooling
  • High-precision machining of medium to large size parts
  • Pulsed high power supplies
  • Thermal and thermo-mechanical management

ALCEN's subsidiaries for Magnets

ALCEN's references

Manufacture of ITER PF coil additional tooling

Remote handling

Due to contamination constraints, the modification, inspection and repair of plasma-facing components can only be done during operation using remote handling techniques. Such systems enable dismantling of the component and transportation to the hot cell for repair or replacement. 

Through its activities in the naval and energy domains, ALCEN has developed a wide variety of technologies for implementation in remote handling systems.

ALCEN's expertise

  • Command & control systems
  • High-precision machining of medium to large-sized parts
  • Robotics

ALCEN's subsidiaries for Remote handling

ALCEN's references

Robotic high-pressure vessel test bench

Vacuum systems

Fusion occurs in vessels which are evacuated prior to operation to suppress molecules which could affect a proper reaction occurring. Furthermore, the plasma density must be kept at a low value during operation and, depending on the design of the machine, additional systems may also require specific vacuum conditions (superconducting magnets, heating systems…).

Considering the reactor’s configuration and volume, several pumping techniques can be implemented: mechanical, ion or cryogenic pumps.

ALCEN's expertise

Through Research Infrastructure activities, ALCEN has developed skills in vacuum technology including design, engineering, material compatibility and preparation, system manufacturing and integration, leak testing and commissioning.

ALCEN's subsidiaries for Vacuum systems

ALCEN's references

Vacuum chamber for ITER PF coil conductor tests

Vacuum chambers and mechanics for mirrors on soft and hard X-ray Synchrotron beamlines

Design, Manufacture and Assembly of LMJ amplifying sections

Manufacture of the ITER pre-production cryogenic pump

Assembly & Operation

In addition to the various complementary skills developed by ALCEN for the design and manufacture of fusion reactor key components and subassemblies, and its proven track record of significant achievements in major programmes, the Group has also developed recognized expertise in work and services related to the assembly, operation and maintenance of complex facilities.

Developing on its expansive technological background and its long experience in the operation of industrial premises and management of long-term programmes, ALCEN has the capability to deploy dedicated staff to customer sites and the resources to conduct assembly work and to operate and maintain specialised facilities, especially those including harsh environments.

All operations are performed in compliance with specific Environment, Health and Safety constraints imposed by the customer.

ALCEN's subsidiaries for Assembly & Operation

ALCEN's references

On-site integration of LMJ laser amplification sections

Assembly of the XFEL Cryomodules

Operation of the Sol Gel Coating facility for LMJ optical components

Maintenance of the LMJ demonstrator