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ARIES Conference Call, 19 April 2005

Documented by L. Waganer

(ANL) -
(Boeing) Waganer
(DOE) -
(FPA) -
(FZK) Ihli (Thomas)
(GA) Turnbull
(GT) Abdel-Khalik
(INL) Merrill
(MIT) -
(NYU) Garabedian
(ORNL) Lyon
(RPI) Steiner
(UCSD) Mau, Najmabadi, Raffray, Wang
(UW) El-Gububaly, Martin


The next ARIES meeting is scheduled to be held at the University of Wisconsin Madison, on Tuesday, 14 June (all day) and a half day, Wednesday, 15 June 2005. Laila El-Guebaly has arranged for a block of rooms and a discounted room rate at the Doubletree Hotel. Please contact the hotel before the negotiated rate expires on May 12. Laila needs to know who will be attending the meeting and if you will be attending the group dinner. Please forward your electronic presentations to Dennis before June 10.

Les Waganer said there would be another conference call in about a month.


The question arose about the status of the ARIES-CS design basis for the September Meeting involving the fusion community that will be held at PPPL. Farrokh said that he wanted to present all the options and their analyses and results at the meeting. Do not narrow the choices before the meeting. The intent is to evaluate the study results to date and utilize the meeting to converge on a design solution or the pathway to a solution.

Compact Stellarator Reactor Physics Basis

Assessment of New QAS and QH configurations Long-Poe Ku said that he had found some very attractive MHH2 two-field period configurations with good physics conditions, namely, low alpha losses of around 2%, good coil configurations, and good separation of coils from the plasma surface. After a little more development, he will forward his cases to Jim Lyon to incorporate into the systems code. Long-Poe Ku should send the preliminary coil center-to-plasma distance to Laila to begin her analyses.

Long-Poe has been working on several improved 3-field period cases that have good flux conditions, higher aspect ratio, beta around 5%, and attractive alpha losses. He will also provide Jim one of these cases to evaluate. It was suggested that Long-Poe send his cases to Arthur Grossman for evaluation, but it was decided to wait until the configuration is more definitive.

Divertor heat load analysis T.K. Mau has been working to develop a simple transport model for the SOL plasma parameters at the target and the LCMS. Hayden McGuinness has succeeded in upgrading the GOURDON code on parallel processors on the Seaborg/IBM platform. He and Art Grossman have also made progress on implementing a Monte Carlo cross-field diffusion model into field line tracing. When completed, this will help evaluate the heat load distribution on the first wall or divertor. There is still some unresolved discrepancy between two versions of the GOURDON code (parallelized and un-parallelized) using the NCSX-based configuration as a test case. The overall intent is to use these tools to locate and size the divertor plates and determine the heat load.

There was discussion about the magnitude of the particle heat flux and the neutron wall load. At present, the magnitude is unknown, but it is thought that a peak heat flux of 10 MW/m2 would be an acceptable limit for the divertor. For preliminary calculations, Laila would like to obtain an estimate of the divertor plate coverage as a fraction of the first wall area. T.K. has provided such an estimate to be ~10%.

Compact Stellarator Integrated Systems Assessment

Systems Code Analysis Jim Lyon is working on the systems code to correct the errors he has uncovered. He requested again for the team to send him any data that may be in error. Laila said she would be evaluating the data and sending Jim her assessment. Jim is concerned about the coil aspect ratio. He had been assuming it was a square cross-section as is the NCSX design. Long Poe said that generally a square aspect ratio (= 1) would be a good assumption for most configurations. He would alert Jim if the aspect ratio significantly differed. Jim also needs data on the shield design for the modular replacement scheme.

Compact Stellarator Reactor Engineering Assessment

Divertor Assessment and Design Approach Don Steiner reported Arthur Grossman and Hayden McGuinness have been working together on the transport model to help predict the heat and particle load on the area where the divertor will be placed.

Power Core Engineering Rene Raffray asked Jim Lyon to send him the specific information Jim needs for the systems code analysis. Rene said the Engineering Group is concentrating on the divertor design and physics basis. They are also working on the dual-cooled blanket with Siegfried Malang. The two maintenance concepts continue to be refined.

Divertor Design Basis Thomas Ihli is developing the T-shaped divertor for the ARIES-CS design that evolved from the EU divertor design. He is presently concentrating on the transition section and the manifolds and plumbing arrangements.

Blanket and Shield Laila El-Guebaly has estimated a helium to LiPb heat load of 42% to 58%. She is assuming the helium pumping power is no greater than 5% of the net electric power. She will assess the impact of the divertor system on the overall breeding assuming the divertor covers about 10% of the FW area and the penetrations about 1%.

She is also working on the decay heat analysis of the LiPb coolant. She will commence work with the UW group on the 3-D neutronics analysis as the student who is scheduled to do this work is leaving shortly. She will also check the results of the systems code.

Decay Heat Carl Martin affirmed he is working on the blanket and shield LOCA/LOFA calculations using the decay heat data from Laila.