Welded Joints. Lack of attention to the details of vacuum sealing weld design, qualification and testing has proved to be a significant cause of vacuum leaks on vacuum systems. All vacuum welds, except those excluded below, shall be qualified, produced and inspected in accordance with Attachment 1. The requirements of Attachment 1 are mandatory until superseded by the ITER baseline Welding Handbook. Where there is regulatory requirement to design and subsequently build a vacuum system to RCC-MR or ASME VIII, the requirements of these codes shall take precedence over the requirements of Attachment 1, while remaining in compliance with Section 7.1.6. In other cases where vacuum sealing welds are to be qualified, produced and inspected to meet a code, and there is variation between the requirements of the code and Attachment 1, the more extensive or stringent requirements shall be applied.