C. Bathke, M. Billone, L. Bromberg, L. El-Guebaly, R. Miller, D-K Sze, M. Tillack, L. Waganer, X. Wang
Mike Billone noted that there is little or no data on rewelding of vanadium. There is some limited data on initial welding of irradiated vanadium, but none for rewelding. There is nothing suspected to inherently limit the ability to reweld vanadium; rather the problem is to find a suitable process.
Regarding the action item to define the hydrogen limit in vanadium, he had proposed a 1000 appm limit as being acceptable and he has received no feedback from the materials community (other than from Dale Smith). Argonne experts felt that 1000 appm limit is conservative either at room or elevated temperatures. Dai-Kai mentioned that this is not a critical limit. The old cross-section data indicated a limit of 6550 whereas new experimental data (from ANL?) indicted a limit of 2170.
Laila El-Guebaly, with Mike Billione's help, is preparing a letter to Bill Wiffen to propose cooperation with the Starlite team on a Web site for material needs, requirements, and data to promote enhanced exchange of materials data.
The topic of the establishment, timing, and technical content of the final Starlite strawman was discussed. It was felt that it would be best to have a self-consistent strawman, but this was not likely to be achievable in the near (or far) term. The integration of the divertor physics into the main plasma physics was the biggest concern. It was decided that:
Dai-Kai mentioned the blanket has been redesigned to accommodate the new segmentation scheme based upon maximizing the useful lifetime of the components. Laila El-Guebaly has defined blanket and shield segmentation based upon full power lives of 2.5 FPY, 7.5 FPY, and life-of- plant. Laila, D-K, Ron Miller and C. Bathke will confer to determine the economic improvement of this segmentation. Igor has defined a sketch of the coolant paths within the blanket and shield. He has been working with X. Wang on the divertor coolant and structure. Thanh Hua has been working on the thermal-hydraulic analyses for the blanket and is planning to complete the analysis for the meeting. He has affirmed that slug flow is the appropriate analysis assumption for the flow conditions. Dai-Kai stated that a LOCA analysis has been completed which indicates that 10 MW/m2 is acceptable.
Les Waganer said that it was possible to report the vacuum system definition and analyses in the configuration section of the final report if the appropriate technical people contributed to the section. D. Lee and I. Sviatoslavsky had been assigned to define the of the vacuum passage behind the shield for the vacuum pumping. D. Cole has laid this area out and can determine the area available. There was to be nominally 50 cm behind shield to vacuum vessel . Les noted that Dick Cole is working with the configuration from Dennis and the detailed dimensions from the 7 May strawman.
Mark Tillack noted that we need to show the approach of attaching the port door to the outer shield and combining the two functions. Mark, Xueren, and Siegfried had worked on defining a support ring that will combine the inboard, outboard and the divertor regions. We should discontinue the terminology of the divertor "cassette" and only use a term to describe the function. Siegfried is working on the support mechanism of the blanket sectors. Dick will develop the building layout.
In the absence of C. Wong, M. Tillack reviewed the divertor results. Elmer Reis of GA has been doing trade studies and has found that increasing the divertor structure to 4 cm reduces the thermal stresses (~200 MPa expected when the 3D work is performed). The extra thickness also provides adequate shielding such that the back of the divertor is now in the 7.5 FPY zone. Results are shown on the Engineering portion of the Starlite Home Page. A 3-D analysis will be done for the final report. Laila El-Guebaly ran the 3-D neutronic analysis on the divertor area and noted that the new surface geometry has helped shield the divertor throat area.
Leslie Bromberg had sent out a memo on the TF coils to a limited set of people, based on the March strawman. The detailed design came within ~1 cm of the model used previously in the ASC. Mark agreed to post the memo on the Web site.
Chuck has modified ASC to allow for 9 PF coil sets.
Leslie is still using 316SS for the coil structure. It seems this will be acceptable. He is also using both NbTi (grade 1 only) and Nb3Sn as superconductor.