Summary of SIT Meetings of 7/8, 7/15, and 7/23

Summary of SIT Meetings of Monday, July 8; Monday, July 15; and Tuesday July 23, 2002.

Since the CDR, the Project has accomplished some important tasks:
- Generated documentation for CD-1
- Re-organized engineering and project control for the next phase.
- Planned the work for the balance of FY-02 and gotten started.

For the last quarter of FY-02, the goals include establishing baselines, preparation of plans and WAFs for FY-03, and executing the remaining FY-02 technical work that has been planned. In this period, there appear to be two critical milestones:

1. Issue RFP for the modular coil mfg. development (9/27)
2. Update the modular coil geometry to a healed design (9/27)

Regarding #2, the M45h design is a candidate, but does not provide an adequate standoff distance between the plasma and the current inner wall for good divertor performance. The physics team has begun an effort to develop candidate designs which increase this distance by shifting the plasma away from the inner wall and toward the center of the VV. Two such designs were issued in early June (known as 1025 and c26a), but progress in healing them has been slow and is difficult to predict. An issue is difficulty in maintaining the edge surface quality in the healing process, which may be due to the proximity of the edge iota to the 6/9 resonance.

As a possible solution to the edge problem, new designs have been developed recently which reduce the edge iota to move it away from 6/9. L.-P. Ku has started trying to heal these.

A design known as "Z05", though not yet healed, is promising for improving the standoff distance and should be checked by Engineering for possible interferences and problems.
ACTION: Nelson / Williamson

So far, the coil designs have been constrained to stay with the CDR winding surface and vacuum vessel geometries. An observation by Mike is that these constraints, in particular the first-wall geometry, may be limiting the ability to come up with a design that has both adequate plasma-wall standoff and adequate iota margin against the 6/9 resonance (expected to be important for healing, but needs to be checked).

It may be necessary to vary the vacuum vessel and possibly the winding surface geometry in order to get a better solution.

ACTIONS:
MIKE: see whether pushing down the edge iota improves the healing process.

BRAD: Intensify effort to try to create more standoff by moving components (e.g., PFCs, ribs, VV wall, RF launcher, trim coils). Use the 2.5% "inflated" M45h equilibrium generated a few weeks ago.

Issues requiring decisions soon:

1. Allow coil designers more freedom in the winding surface and/or vacuum vessel and internal component geometries? Need above actions to determine what is useful and what are the engineering consequences. Decide in ~2 weeks.
BENEFIT: More freedom to come up with a satisfactory coil design should expedite resolution of deficiencies.
RISK: Cost and schedule impact of engineering re-design to ensure adequate assembly clearances.

2. Selection of baseline coil design for the project. Decide by end of September. Choose from healed candidates available at that time.

3. How much effort, if any, to devote to continuing to try to improve the coil design after baseline is adopted?
BENEFIT: Possibility of better physics performance.
RISK: Cost and schedule implications of making a fundamental change in the design several months into the project. 
Evaluate benefits and risks at the time of coil selection, and decide on future efforts then.

Next SIT Meeting: Tuesday, July 30, 2002, 11:00 a.m. EDT. Usual arrangements.

Please bring any corrections or comments to my attention.

Thanks to all,
Hutch

Please forward any questions or comments to mailto:reiersen@pppl.gov

Return to NCSX Engineering Home Page