Technical Code Issues of ITER Vacuum Vessel and Their Resolutions

Abstract

The ITER vacuum vessel is a double-walled torus with large-sized quadrilateral ports needed to provide quite a high degree of vacuum for deutrium-tritium fusion reaction. Access to the outside of vacuum vessel is limited during assembly welding, because it is installed after assembled with surrounding toroidal field coils. From the radiological safety aspect, the vacuum vessel functions as a physical barrier to enclose radioactive materials. Therefore, construction of the vacuum vessel needs application of newly developed technologies on design, fabrication and examination. The technologies include design approach by finite element analysis, and partial penetration T welded joints to join ribs to outer shell. Several issues have to be resolved for applying those technologies to the vacuum vessel. This paper describes several newly developed technologies and key issues for such applications.

KEYWORDS:

• ITER
• fusion
• vacuum vessel
• structural technical code
• partial penetration
• welded joint
• crevice corrosion
• non-destructive examination
• double-walled structure
• code acceptability