With the construction, installation, and commissioning of the third-generation n_TOF spallation target, it has been proposed to execute an autopsy of a second-generation target aimed at analysing the internal status of the core and evaluate the presence of erosion-corrosion damage and plastic deformations due to interaction with beam and creep.

The accomplishment of this task relies on the execution of the following activities: a) cut the aluminium frames of the vessel and the stainless steel handle in order to fit the target into the standard containers usually employed at CERN for long term disposal of radioactive devices; b) cut and extract the two aluminium windows at the side of the target, in order to have access to the lead core; c) extract samples of lead and perform, firstly, a visual inspection through HD pictures and 3D scan, and then an ultrasonic inspection, in order to detect even the smallest defects on the target core surfaces.

The complexity of the tasks to be performed, together with the requirements in terms of accuracy for the correct extraction of the windows, would have been translated into a huge amount of exposing time to ionized radiations for the human personnel. At this purpose robotic solutions play a key role, since they allow not only to perform such heavy tasks with great accuracy, but also remotely, guaranteeing the safety of the personnel - the estimated saved dose per person for the execution of this intervention is about 90 mSv.

In that specific case, the robotic solution consists of a 6 degrees of freedom industrial robot arm equipped with an air-cooled electro spindle, and two teleoperated robotic platforms (i.e. Teodor and CAMbot) supporting the milling operations and performing the inspection tasks.

Intervention Procedure

Hereafter are illustrated the various steps characterizing the intervention, starting from the positioning of the target, until the removal of the windows and the different inspections performed on the lead core surfaces.

• Target clamping on the rotary table

• Vessel frame and handle removal

• Potton and Neutron window removal

• Cleaning of the intervention area and target top surface

• Lead core and windows 3D scan

• Ultrasonic inspection

• Lead core endoscopy and sampling

Intervention Procedure (video)

"G:\Projects\Robotics\01. Interventions\01. Done\2024\n_TOF_V7_collage.mp4"