FROM: Larry Stewart
SUBJECT: Minutes of the Feb 28 - March 3 PULSAR Project Meeting at UCSD
The seventh PULSAR Project meeting was held Feb. 28 - March 3 at UCSD. Technical interchange sessions on systems analysis, magnets, safety, physics, RAM and engineering were held on Feb. 28 - March 1. Summaries in each of the areas were presented to a review team on March 2. Remaining issues, review team advice and schedule constraints were factored into a plan for issuing the final strawmen on March 10 and completing the report draft by April 8.
The PULSAR work was reviewed by a committee consisting of John Davis (MDAC, chair), Ian Cook (AEA), Hiroshi Matsumoto (ITER JCT), Pete Politzer (GA) and Tom Shannon (FEDC). On March 2, we presented a project overview plus summaries on systems analysis, physics, magnets, engineering, safety/environmental and RAM. The committee responded with a presentation of comments and recommendations on March 3. An important message derived from their presentation is that we must do a better job of explaining what we have done. The committee will provide a written report.
REMAINING ISSUES & ACTION ITEMS
Magnet stresses: The baseline PF set results in 100 MPa stress on TF and further optimization will at best provide ~ 10% effects. Bromberg will look at reduced initial crack size to see if 75 MPa is acceptable. Najmabadi/Sharafat will send a divertor sketch to El-Guebaly so she can give corrected shield dimensions to Bathke. Bathke will then move the outer legs inward to the limit for our maintenance approach and will add TF thickness until the stress criteria is met.
Magnet costs: ASC magnet costs are important in determining our COE-optimized strawmen and these costs appear low when compared with ITER EDA. Bromberg will complete the comparison and look for possible reductions. Miller will review Bromberg recommendations and revise ASC as needed.
Divertor design: Wong is coordinating parallel tasks being done by most of the engineering team and requests all report inputs by March 20.
PULSAR II energy storage shield: John Davis says 10-25 appm neutron-induced He at the grain boundaries will weaken the V-structure at 700C. El-Guebaly will calculate helium production. Sager will see if the maximum temperature can be reduced to 650C. Hydriding and creep fatigue and will be discussed generically in the report.
Hybrid recharge: No hybrid recharge in the strawmen. Mau will write upwhat was done and what remains to be done. Ehst will use previous studies as a basis for discussing potential advantages.
AC vs DC: Bathke will make a choice based on ASC comparisons.
Pulse/steady state comparison: Use the credible PULSAR designs resulting from the resolution of the stress issue as described above. Compare subsystems with those of ARIES-I. For cost comparisons, Bathke will make only the few adjustments to ARIES-I needed to provide and equal basis, e.g., magnet current density. Bathke will send out a few adjusted ARIES-I trial cases for comment. Miller will determine if we have enough information for a story on the impact on availability. If not, availability will be done parametrically. For disruptions, we will apply the data base (assembled by Ehst) after extrapolation, i.e., we will be able to do a factor of 10 better.