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Summary
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1.
Vacuum Vessel Schedule Risks
We are making progress in coming to closure on the critical vacuum
vessel design decisions:
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We
will likely retain the current vacuum vessel segmentation scheme. The
alternatives have too many unknowns for this stage of the design,
consequently high risk to the design schedule. We expect to confirm this
decision at next SIT.
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This
week, Art Brooks will tweak the vacuum vessel shell geometry to try to
increase plasma-wall spacing within the existing segmentation and
assembly constraints.
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On
350 C bake, we will try to wrap up the decision by next SIT, but the way
things appear to be heading is:
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The
tube attachment issue can be resolved by eliminating the requirement
to cool the vessel. If they only have to heat the vessel (a slow
process), mechanical attachments (clips) can be used, avoiding the
need for high-temperature epoxy or welding. Electrical heaters need
to be installed on the ports. The program risk is that the cooldown
time for 12 MW plasma pulses my be longer than 15 mins. The benefits
are increased plasma-wall space and reduced operational costs and
risk due to thinner PFCs that do not need a separate cooling loop,
except possibly for local hot spots such as divertor plates.
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The
thermal expansion issue is probably limited to port interferences
requiring some modifications of the port ducts, but currently
thought to be workable. The homework still needs to be finished on
this issue. ACTION: Goranson.
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The
thermal cycling of the vacuum vessel at ~400 C is thought not to be
a feasibility issue but could be prohibitively costly. ACTION:
Goranson to follow up with suppliers.
The
goal is to resolve the 350C bakeout issues this week and decide at the
next SIT.
2. Modular Coil Schedule Risks
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CAD
modeling of the MCWF is making progress and, it is hoped, will be
resolved this week. The T. Brown approach is working well. The
Williamson approach is still being pursued. The Hargrove approach has
been dropped. Hargrove is working on “tool solids” modeling needed
by J.P. Pattern. It is anticipated that the Brown approach will be
able to model all three MCWF’s, without interferences. This has not
been demonstrated yet but it is hoped to be completed this week.
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Structural
analysis remains an issue, but resources have recently been added to the
global modeling task (H.M. Fan) and we expect to make progress with
simpler approaches in parallel, and have a story by the FDR. The plan
for documenting all needed load cases still needs to be fleshed out and
incorporated in the WAFs. ACTION: Williamson.
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In
a separate discussion, Williamson advocated making fuller use of the
prototyping activities to develop the process for accurately winding the
coils. Multiple metrology approaches may need to be tested to determine
the best approach for use in coil production. ACTION: Williamson follow
up with metrology and coil winding groups to ensure needed tools are
being procured and to develop the plan.
3. Technical Risks
Wayne led a discussion of critical technical issues and updated a
tracking list which has been developed. Highlights not already covered:
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We
do not yet have an adequate R&D plan to develop the reference
material properties and design criteria, and resolving cure strain
inconsistencies. ACTION: Brad, develop the SOW for the R&D program.
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We
need the magnitude of field arrors from structural steel around the
machine. ACTION: Wayne follow up with Brooks and Strickler to determine
responsibility.
4. CD-2 preparations
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The
Change Control Board met on 12/8 to review changes to the GRD. A
handfull of issues requiring follow-up was identified and assigned. It
is expected that the GRD changes will be approved before the holidays.
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The
PDR, PBR, and EIR disposition plans are out for review and response by
the WBS managers by Friday, Dec. 12. ACTION: Neilson follow up.
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The
ECP documenting changes from the PDR baseline to the CD2 baseline will
incorporate review responses and any changes to the DOE funding profile.
Project-initiated changes resulting from the WAF planning and updating
processes will, as a rule, not be incorporated into this ECP but swept
up at the next Lehman review. Exceptions will be considered
case-by-case. They may entail calls on contingency.
5. Next SIT Meeting: Monday, December 15, 2003 at 1:00 p.m.
(Note special time.)
Summary by:
Hutch Neilson
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