The commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at QST Rokkasho Institute for Fusion Energy within the engineering validation of the accelerator system up to 9 MeV/125 mA in continuous wave under international collaboration between Japan and Europe. Several SRF cryomodules will be required for IFMIF to accelerate deuterons from 5 MeV to 40 MeV. The prototype of the first of these cryomodules has been manufactured and will be installed and tested on the LIPAc. It holds the eight Half Wave Resonator and RF couplers to accelerate the beam and the eight superconducting solenoids to focus it. During the cryomodule assembly, several non-conformities were identified, including vacuum leaks and cryogenic pipe issues. These challenges were addressed through a coordinated effort involving Japanese and European partners. Solutions included the refabrication and repair in Japan of critical components, adhering to Japan’s High Pressure Gas Safety Act and international standards. Material selection, thermal cycling treatments, magnetization assessments, and regulated welding with non-destructive tests (pressure and penetration) were jointly implemented. This poster outlines the technical approaches taken, highlights the collective efforts of the LIPAc team in resolving the encountered issues, and reports on the progress toward the successful assembly and validation of the LIPAc SRF cryomodule.

In complement to the development activities for fusion reactors (JT-60SA & ITER), Fusion for Energy contributes to the R&D for material characterisation facilities. The LIPAc, technical demonstrator for the production and acceleration of a D+ beam, will be used for neutron production by nuclear stripping reaction on a liquid Li target. Since its first beam in 2014, the LIPAc construction and commissioning continues and will be concluded with the cryomodule installation aiming for beam validation at nominal power. The cryomodule assembly, started in March 2019, was paused for two and half years, devoted to improve the pumping, repair, cold tests and high pressure rinse the solenoids. In August 2022, the cleanroom activities resumed with the cavity/coupler assembly but had to be paused again to fix a leaking bellows on a solenoid. In September 2024, the beam line left the cleanroom to start the cold mass assembly phase which was concluded in January 2025 with the cold mass insertion. In March 2025, the cryomodule was transported to the accelerator vault for the last assembly steps before its integration. The team is working on the connection of the super-conducting solenoids. The final leak tests of the cryomodule, conclusion of its assembly, are expected in the second half of 2025. This paper presents the technical challenges encountered and their solutions, highlighting continuous progress in overcoming complex integration issues across a synergic international collaboration.