CEA's UP1 plant in Marcoule is home to the 71-21D vessel, which is particularly irradiating (250 Gy/h). To support sampling and investigations in this tank, Onet Technologies teams have developed a digital twin to simulate the configuration of the booms that will be lowered into it, developed by our partner CLEO. Explanations with Quentin Schneider, deputy manager of the mechanical department, Florent Serre, mechanical and ECC (electrical control and command) manager, and Jules Zimmerman, apprentice mechatronics engineer, our Onet Technologies employees who worked on this mechatronics project.

Investigating tank 71-21D: an unprecedented radioactive challenge for our teams

The aim of the overall service provided by Onet Technologies is to carry out investigations and studies for the dismantling of tank 71-21D at CEA Marcoule's UP1 facility. These investigations are part of the acquisition of basic data for decontamination/dismantling operations and the recovery of deposits in tank 71-21D.

This vessel is particularly irradiating (250 Gy/h), even more so than the elephant's foot at Chernobyl, so Onet Technologies is faced with a very risky project at the Marcoule site. To intervene in the tank, our partner CLEO has developed a remote-controlled arm capable of descending into this extremely hostile environment. But to guarantee the precision and safety of interventions in the face of this unprecedented radioactive challenge, Onet Technologies' teams have also designed a digital twin* to display the booms in the tank in real time.

Operation of the digital twin developed by Onet Technologies to investigate tank 71-21D

The digital twin created by the Onet Technologies teams for the 71-21D tank investigations interfaces with the investigation booms developed by our partner CLEO, which will be lowered into the tank to take samples. It enables the pilot to appreciate the actual position of the boom in a 3D environment.
In fact, only one camera can be present in the tank. However, the pilot needs two cameras to be able to appreciate distances, in the same way as the eyes do with their binocular vision. This is precisely the point of the digital twin, which is there to compensate for this absence of binocular vision , and which consists in projecting the investigation poles into a 3D scene. The operator can then move in any direction within this 3D scene.

To debug this system, the Onet Technologies teams simulated the operation of the booms on a physical engine from the CEA. To ensure that it was working properly, they then connected the digital twin to this physical engine, in the same data transfer configuration as the real thing, prior to the start of the actual worksite.

When moving on to the actual tank, an investigation and reconstruction of the tank will have to be carried out, as the construction drawings may vary from the actual tank configuration.