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Decontamination and


Engineering and services for Decontamination and Dismantling

Onet Technologies is one of the most important D&D actors in France, with decades of experience in this field. D&D is one of our true core businesses and we support our clients in France and internationally throughout their projects: From the very first studies until the completion of the on-site operations. 

Onet Technologies is a company dedicated both to engineering and services, with a staff composed of engineers and on-site workers. We benefit from a real user’s feedback, with knowledge of the costs-benefits, which we integrate into our designs of solutions. With a system engineer approach we integrate the best proven and innovative technologies in solutions to complex D&D challenges. 

Our Activities

  • Dismantling studies, expertise and advice in all fields of Engineering

  • Investigations, radiological characterizations and creation of digital twins

  • Design and development of special decontamination and dismantling equipment

  • Dismantling of research and reprocessing facilities, experimental and power nuclear reactors

  • Delegated operation (on behalf of the owner) of nuclear facilities being decommissioned

In Japan, Onet Technologies with
Japanese and French partners to offer

Nuclear Engineering, with studies and design of solutions for D&D projects

Nuclear Engineering, with studies and design of solutions for D&D projects

Our engineering department has decades of experience, competences in nearly all fields of engineering relevant to D&D projects and benefits from the operation feedback of our own staff carrying out D&D works.

Our added value

  • With system engineering, integrate technologies in solutions to complex D&D challenges while bringing our operational feedback, nuclear safety culture and risk management approach (such as avoidance of future costs).
  • Expertise of specific aspects of D&D studies (such as remote operability / maintainability in high activity environment) and designs (such as optimization of D&D operations as per radiation protection, waste and cost-time criteria).
  • Address very complex topics with a systemic approach to firstly deduct important directions before progressing with iteration-based engineering.

Support to the Japanese R&D, to improve projects or to solve unique challenges

Support to the Japanese R&D, to improve projects or to solve unique challenges

We have been following the same approach from the start because it has always proven successful.

Firstly, we focus on actually supporting the Japanese R&D. We bring complementary expertise and R&D capacities or results.

Secondly, we always seek partnerships. We bring together European and Japanese technologies and R&D results in our projects.

Innovative and proven Technologies, adapted and tested to meet our clients’ challenges

Innovative and proven Technologies, adapted and tested to meet our clients’ challenges

We have knowledge of the actual performances of D&D technologies based on a long experience of use by our own staff. While we understand the value of proven solutions, we also believe that innovation is one of the main levers to improve the D&D projects and we take part in the realization of first cases of application to demonstrate the merits of new technologies.

On this basis, we can support the integration of the Best Available Technologies (conventional and innovative) in D&D solutions from the identification of the technologies, through testing, adaptation and demonstration of the specific benefits until the support to their deployment in Japan.

Key Project

Our key D&D projects in Japan so farsince 2013

We support the R&D for the dismantling of Fukushima Daiichi by participating to the Project of Decommissioning and Contaminated Water Management.

We bring relevant D&D technologies from France and adapt them to the challenges of Fukushima Daiichi to make their use in this complex environment as safe as possible


Series of projects aiming at developing a safe and efficient application of laser cutting technologies to the Fuel Debris Retrieval

Conceptual Study of Innovative Approach for Fuel Debris Retrieval and Feasibility Study of Essential Technologies

The purpose of this project was to study the feasibility of cutting Fuel Debris with laser and collecting dust and fumes generated.

The project demonstrated the good performance of the laser cutting technologies and produced important outputs in respect of dust and fumes collection, radiation resistance and requirements for on-site deployment. (EN)


Project of Development of Fundamental Technologies for Retrieval of Fuel Debris and Internal Structures

With this project, the laser technologies applied to Fuel Debris cutting were further developed as per 4 variants for in-air / underwater operation and emerging / non-emerging cutting method.

Important results were obtained to increase the knowledge of particles and gases generated during Fuel Debris cutting and the feasibility to collect particles in air was further demonstrated with a prototype.


Advancement of Fundamental Technologies for Retrieval of Fuel Debris and Internal Structures

This project has achieved significant results in laser cutting development, dust and fumes knowledge and aerosols mitigation.

Safety systems were introduced to mitigate dispersion and collect aerosols for each variant of Fuel Debris laser cutting (in-air / underwater and emerging / non-emerging cut). (EN)

Development of nuclear measurement technologies for the purpose of safety

Development of small neutron detectors

With this project we participated to the first phase of development (Feasibility) of a Small Neutron Detection System (SANDY) in answer to a Challenge at to detect the Fuel Debris inside the Pressure Containment Vessels. (EN)

Project focusing on the safe collection and filtration of dust and aerosols generated during Fuel Debris Retrieval (mechanical and thermal cutting techniques, including laser)

Development for Dust Collection System of Fuel Debris (Collect and Filtration of dust and aerosols)

This project capitalized on past developments made in line with laser cutting developments to advance towards the best safety system to mitigate of the main risks of Fuel Debris Retrieval: Dust and aerosols dispersion.

Thanks to an increased knowledge of the properties of dust generated during Fuel Debris cutting (with mechanical and thermal techniques), the safety system was further developed in:

Spray scrubbing (mitigate dispersion)

Local collection (reduce the risk of dispersion by removing dust at the source – near the cut)

Extraction (safely retrieve the dust collected) (EN)

Other important projects Japan in the field of D&D include:

  • Particle Generation Test Using Simulated Uranium Containing Debris (characterization of aerosols). This project involved cutting active (with Uranium) simulant of Fuel Debris.
  • Studies to support the definition of remotely operated D&D solutions for Japan.(not only for Fuel Debris Retrieval).
  • Tests of D&D technologies aiming at demonstrating their capacities to meet the requirements of Japanese clients.

Laser Cutting
for Nuclear Decommissioning

Adapted to in air and underwater cutting for remotely operated nuclear dismantling with many merits compared to conventional techniques.


Successfully tested on high thicknesses (up to 200mm of stainless steel with a 14kW laser source)


Laser cutting offers excellent cutting performance by remote control while offering impressive position tolerance when cutting heterogeneous layers of materials (Carbon steel, stainless steel, titanium, zirconium, …)

  • 1


     for the workers (remote operations)

  • 2

    Time reduction and cost efficiency

    in operation

  • 3


    of the secondary waste (aerosols and mass removed from the piece)

  • 4

    Robustness & reliability

    No maintenance or wear parts in controlled area

  • 5

    Effortless cutting

    with high performance

The L.DCom product was proven in France. 

Introduced by Onet Technologies as a world first in December 2015, the technology has demonstrated its full potential in the project to dismantle UP1 dissolvers in the spent-fuel reprocessing facility at the CEA Marcoule site in France.

4.5 tons have been cut with the laser cutting technology handled by a robotic arm.


The technology can address unique challenges. 

Onet Technologies is working with partners since 2014 to further develop the laser cutting for the very complex applications at Fukushima Daiichi

Test of a high-performance system of mitigation and collection of the dust and fumes generated during laser cutting, suited for remote operations in extreme environments.

This innovation can improve D&D projects  

While the technology was first proven on a case of dismantling of a fuel cycle facility, laser cutting can bring a high benefits over costs ratio for several types of D&D projects: Fuel Cycle, Research and Military facilities, but also Power Nuclear Reactors.

For Power Nuclear Reactors, a specifically interesting application is the dismantling of the reactors themselves, i.e. the pressure vessels (RPV) and internals (RVI). The demonstration of the Safety and Cost & Time benefits of using the laser cutting technologies for RPV and RVI dismantling the goal of our on-going LD-SAFE project (2020-2024).

Your contact
Julien Guillemin
Japan Area Business Development Manager

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