Manufacturing and Fatigue Tests of PF1 Coil Helium Inlet

The Poloidal Field (PF1) coil is one of six PF coils of the ITER magnet system. The PF1 is composed as a stack of eight double pancakes (DPs). The DPs are wound from NbTi superconducting cable “cable-in-conduit” type and have cooling by liquid helium. The supplying of liquid helium is carried out through helium inlets, which are one of the critical structural elements of DPs and PF1. During the PF1 coil operating, helium inlets are undergone by cyclic mechanical loads. In this case, it is necessary to check the design of helium inlets by carry out fatigue tests at cryogenic temperature. In 2013, the design of helium inlets was changed. In accordance to these changes, the new manufacturing process of helium inlet was developed. A new helium inlet sample was manufactured. The fatigue tests of this sample were carried out in accordance to ASTM standard E739-91(1998) “Standard Practice for Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (e-N) Fatigue Data.” This paper presents comparative analysis of manufacturing process of previous and new helium inlet designs, details, and results of fatigue tests.