The first completed port stub extension—for upper port #12—has successfully passed pressure and helium leak tightness tests. There was tangible tension among the observers assembled at the testing of the ITER vacuum vessel component when the pressure gauge reached the 3.78 MPa mark. The tolerances on the massive double-wall stainless steel structure were tight, the welding a challenge. After half an hour of mandated holding time, the full pressure test of ITER’s first completed upper port stub extension (#12) had been completed successfully.
The ITER vacuum vessel has 44 openings, or ports, on three levels (lower, equatorial and upper) that are used for equipment installation, utility feedthrough, vacuum pumping, and access into the vessel for maintenance. The upper ports are characterized by a trapezoidal/rectangular cross-section due to a slight upward slant. This has to be taken into account in the design of their port structures, including port stub extensions and port extensions. Each port stub extension includes double-wall and single-wall parts.
In respect of French regulations on pressure equipment (ESPN), which apply to the ITER vacuum vessel, a full pressure test followed by a helium leak test to confirm the high vacuum tightness of the component were performed in the presence of an Agreed Notified Body (ANB) before the final machining of upper port stub extension #12.
