Farrokh Najmabadi noted that there were no significant administrative actions to
mention. Miller, Najmabadi, Tillack, and Waganer (and J. Davis) are planning to
attend and participate in the Fusion Power Associates Symposium, "Pathways to
Fusion Power", in Colorado during 27-29 August. The next meeting is still
scheduled for all day on both Thursday, Sept 25 and Friday, 26.
Les Waganer noted that effective 4 August, MDC will be merged with Boeing to
become The Boeing Company. Company letterheads, signs, logos, and E-mail
addresses will be changed (new addresses are firstname.lastname@example.org and
email@example.com) but little else is anticipated to change. [Let Waganer
know if the new Boeing mail system is causing you problems.]
PS, The new Boeing High Energy Systems Web page address is http://www.boeing.com/
assocproducts/hienergy/ in case you reference or link to it.
Steve Jardin did not participate in the call, but Ron Stambaugh gave a quick update
on GA activities. He noted that the PPPL and GA analyses and results seem to be
converging on a common basis. TK Mau is currently at PPPL to confer with Martin
Peng. Ron S. questioned if the modified coil locations have been assessed.
Specifically, would the maintenance schemes allow the PF coils to be closer and/or
the TF coils to be smaller? Could the PF coils be located inside the TF coils? Farrokh
had discussed these topics with Steve Jardin but the issue has not been fully
investigated or resolved. The present TF and PF coil configuration is somewhat of a
legacy item from the Reverse Shear (RS) design, and the new groundrules for an
ST/LAR configuration have not been fully or rigorously investigated. The coils
could be smaller and/or interleaved, depending on other factors such as the coil
connections, coil leads, and maintenance provisions. One difficulty is that the PF
coils will likely be S/C; and when inside the TF, the cooling of the coils and TF coil
connections are key issues. Steve had investigated some of these geometry effects,
but could not seem to achieve the triangularity required.
Ron Miller noted that JSOLVER could position the coils closer to the TF coils. The
outer cryostat (also a legacy from ARIES-RS) will be removed, with individual
cryostats around each PF coil. These effects need to be added to the codes.
Mark Tillack was on vacation but several others reported their status.
Blanket and Thermal Conversion - Dai-Kai Sze had several questions or
He questioned the feasibility of the water-cooled center column for a power-
producing reactor, especially considering the safety issue associated with a LOCA
and electrolysis with dissimilar materials. He noted that TFTR and JET have
abandoned the use of water in their magnets, but Doublet III continues to use
water-cooled magnets. He has talked to TFTR people who stated the reason for
disuse of water is the inability to stop leaks at the joints. Ron Stambaugh noted
that Doublet III has not had problems with excessive leakage. Pulsed loading is a
contributing factor which would be mitigated on a steady-state machine. Water
chemistry continues to be a difficult problem. Inorganic coolants would not be
usable in the high radiation environment. [No resolution - continue
Dai-Kai has been examining the LiPb coolant option proposed by Malang et al. The
difficulty is the inability to find a suitable heat exchanger design and material
combination that is compatible with the LiPb coolant. His suggestion was to
eliminate this option or to continue with this coolant option and state that there
will be a future breakthrough in HX design. The latter was not acceptable with the
group. [Tentatively assume that there is no present solution, but continue
investigation of this topic (see next paragraph).]
What blanket system should be used for the reference Systems Code case for the
September meeting? So there would be a definitive blanket/coolant system
available for use with the Systems Code, the Li/V blanket/coolant system will be
used. It will be similar to the ARIES-RS blanket/coolant system. However,
Farrokh wants Dai-Kai to continue to investigate and document the problems and
issues associated with the FS/LiPb blanket and cooling systems. These issues and
problems must be defined so that people who are proposing to use this system in
less ambitious applications will understand the reasons for our actions in the
power plant application.
Configuration and Maintenance - Farrokh Najmabadi reported that there
has been no progress on the maintenance and configuration task.
Safety Analyses - E. Mogahed has constructed a new model for the LOCA.
The busbar is assumed to be the ultimate heat sink and is located outside the main
power core (do not use the R-word). However he was not sure of the dimensions to
use. R. Miller and W. Reiersen will coordinate to determine suitable busbar
dimensions for E. Mogahed to use. Elsayed said his model is now using the wedge-
shaped center post design.
Hesham Khater noted that one of Mike Corradini's students at UW is working on
the safety analysis of the lithium and water reaction, which may be applicable to
future ARIES work. There is added capability being incorporated into their existing
code. In regard to a question raised by W. Reiersen at the Madison meeting,
Hesham said that the waste from an unshielded aluminum centerpost would be
acceptable under 10CFR rules, but the Fetter limits would result in a level of Al26
that is double the allowable limit for Class C disposal. If the centerpost is shielded,
the disposal of the aluminum centerpost would be acceptable and the shield would
be thinner than the one for copper (@ 30 cm).
High Heat Flux Components - No discussion.
Ron Miller stated that he and Chuck Kessel have conferred. Chuck generated a
EQDISK file for the A=1.6 regime. Ron has now developed systems code results for
aspect ratios of 1.25, 1.4, and 1.6, with the latter looking much more favorable. For
the 1.6 case, the current requirement is reduced, which makes most other data more
favorable. More space is available in the center column, a better recirculating power
fraction is obtained, and a smaller machine is forecasted. He will report the 1.6
strawman sometime in advance of the September ARIES meeting.
Ron turned on the availability subroutine in the systems code. Although the
maintenance data has not been validated, the preliminary results were generally
negative in the availability (and COE).
Dai-Kai noted that when we approach the 1.6 aspect ratio (or so), breeding only in
the outboard region may not be adequate and we have to start breeding on the
inboard side also. Ron agreed that this effect had not been included and will have to
be incorporated at a future time. However, both agreed the crossover point has not
Les Waganer reported that he incorporated into his alternate application database
some modifications from several suggested alternate weighting schemes resulting
from the Madison meeting presentation. The presentation was modified, based on
suggestions from Bill Dove and Farrokh Najmabadi, for use in the presentation to
DOE-Office of Fusion Energy Sciences, namely Anne Davies and others. The DOE
personnel generally agreed with the approach and results and suggested a more in-
depth investigation within the available budget. The essence of this presentation
will be given at the FPA symposium in August. Farrokh also gave the results of the
ARIES-RS study to a subset of the same DOE audience.