Manufacturing, on-site installation and acceptance test activities of the MITICA vacuum vessel

The ITER Neutral Beam Test Facility, in an advanced stage of construction in Padova, includes the installation, tests, and optimization of the full prototype of the ITER Heating Neutral Beams injector (HNBs), named MITICA. The MITICA Neutral Beam Injector will host its main components in a SS304L vacuum vessel composed of two modules, connected between them on site: the Beam Source Vessel (cubic shape of 5 m side and 67 tons weight) containing the Beam Source and the Beam Line Vessel (section 4.5 m x 4.5 m, length 11 m and 76 tons weight) containing the Beam Line Components and the Cryopumps. The manufacturing is described, going through the FE analyses performed to assess the structural integrity, the materials selection, the welding qualifications, the implementation of the double barrier sealings and the control of the deformations. The Factory Acceptance Tests of the individual vessels are presented, including their Helium Leak Tests. The two vessels have been assembled on-site inside the MITICA bio-shield. The main outcomes of on-site final assembly and Site Acceptance Tests are described. Both the vessels have been detail designed, manufactured, installed and tested by De Pretto Industrie, from Schio, (VI) Italy, supporting fusion technology's applications from more than 50 years. The design and the technical support were provided by Consorzio RFX, while the procurement was managed by Fusion For Energy.