Gary Johnson

The Vacuum Vessel (VV) Final Design Review was held on July 21-23. This review was critically important to the project because the vessel is a safety class component that forms part of the first containment barrier. Also it is on the project critical path, and it interfaces with many different systems so its design has far-reaching effects.

The review was chaired by Brad Nelson from the US Domestic Agency (DA) and consisted of committee members, DA members as well as independent experts, from the EU, Korea, the Russian Federation and India. The scope of the review included the main Vacuum Vessel and its ports — including the ELM coil interfaces — which are included in the first VV Procurement Arrangements (PAs). Systems which will be included in these PAs later or in later PAs (such as the in wall shielding, blanket manifolds, and VV supports) were not included in the review but their interfaces were discussed.

Major topics discussed at the review included requirements (including safety and regulatory requirements), analyses, the design, interfaces, manufacturability, assembly plans, risk assessment, the schedule, and the annex B of the PA's describing the manufacturing requirements, drawings, welding and documentation and acceptance requirements. All of these topics are important but the analyses, interfaces, and topics related to tolerances (both manufacturing and assembly) were of particular interest to the committee.

After the intensive three day meeting, Brad Nelson took a positive view of the review had achieved. The functional requirements for the System Documentation appear to be met, the critical analyses have been done. Out of the 67 interface documents 23 have been signed. Also, the main interfaces between the ELM Coils and the Vessel are being defined. Thus the design and analyses are now sufficiently defined to allow the PA to be finalized — jointly with the DA's — so procurement can proceed.

Clearly, much work remains to be done particularly related to finalizing analyses, interfaces, and the incorporation of the ELM coils. But this review confirmed that the design meets the requirements and will help focus our efforts over the coming weeks as we move toward the completion of the PA. Completing the resulting action items from the review is critically important in order to proceed with the PA and thus it is one of the highest priorities for the project. As has been in the past, it will take a collaborative effort with all ITER technical departments to resolve these issues efficiently and rapidly so we can move forward.