ARIES Documents -- Meetings ArchiveARIES Conference Call, 31 March 2010
Documented by L. Waganer
Mark Tillack noted that the "Edge Plasma Physics and Plasma Material Interactions in the Fusion Power Plant Regime" will be held on 20-21 May 2010 at the UC San Diego. The agenda is very full and it is anticipated there will be excellent attendance (about 30 people have pre-registered) both from the US and abroad including ITER staff. Rob Goldston intended to come, but has a conflict and Jon Menard will come instead. Mark said that it is possible to have the ARIES meeting earlier that same week and save travel expenses.
Per Mark Tillack, Farrokh Najmabadi had said that we need to have an ARIES project meeting sometime in May, preferable on the East Coast to accommodate DOE attendees, perhaps at PPPL. Farrokh suggested scheduling the meeting sometime in the first week of May. The group also mentioned if DOE were not planning on attending, having the meeting earlier in the week of the Town Meeting would save travel expenses. Les Waganer was to set up a Doodle poll to canvas the team on potential dates in May (this has been done). It was stressed we need to present progress since the December meeting. [Note: The ARIES meeting is now scheduled for 19 May 2010 at UCSD.]
Mark Tillack discussed the results of the January 28, 2010 meeting with Al Opdenaker, Ed Synakowski and some members of the OFES staff to discuss ARIES budget and future plans. Initially, the meeting was to have only been with Al and Ed, but that morning, the meeting was expanded to include the OFES staff, so the presentation was adjusted accordingly. The ARIES personnel attending were Farrokh Najmabadi, Mark Tillack and Laila El-Guebaly. The meeting was intended to be about an hour, but Ed was very interested and the meeting extended beyond the scheduled time. Mark said he would distribute the presented slides to the team. The planned work scope seemed appropriate. There was some DOE interest in the ARIES team helping to plan and develop the next machine between ITER and Demo, but this was quite indefinite.
ARIES Technical Efforts
Lane Carlson has been completing the systems code work started by Zoran Dragojlovic and has started running representative cases and compiling data (very large data sets) to be analyzed. He is concentrating on how to display the data in meaningful ways to analyze the results and parameter scans. He has succeeded in running the code on the PPPL (computer) cluster, which allows a faster run time with more data sets. Mark noted he was interested in plasma elongation as a significant parameter. We might consider 2.0 or 2.2, as well as allowable heat flux on the divertor, perhaps in excess of 10MW/2. Chuck Kessel is interested in radiated power fraction, particularly in the heat flux distribution. Another possible interesting parameter is the peak magnetic field at the TF magnets. Chuck Kessel suggested we might want to increase the current density in the TF coils as this might lead to a new magnet design. We might consider high temperature superconductors, but this is a new "ballgame". Dale Meade noted that we must assess the neutron damage to the superconductors as determined by the cumulative shielding capabilities. Laila El-Guebaly noted the HTS conductors need more shielding to have a lifetime comparable to that of the low temperature superconductors.
Laila El-Guebaly is moving from the inboard neutron streaming assessment to that for the outboard region. She has some outboard shielding design solutions to be evaluated and is considering constructing a 3-D model as the CAD drawing is not available yet. UW has a set of codes to evaluate the biological dose after shutdown. This is an important parameter for consideration during maintenance. The UW methodology was applied to ARIES-CS and compared to the approximate Contact Dose approach. A report was recently published as a UWFDM-1375.
Chuck Kessel did not have anything significant to report except he and Lane Carlson are working well together on the systems code and case simulations.
Xueren Wang has been working on the first wall design concentrating on the armor solution. His design solutions include consideration for fabrication as well as 2-D FEM analyses on time-dependent transient conditions during rapid plasma shutdown (both cold and warm scenarios). He provided some of his findings at the recent US/Japan Reactor Design Workshop.
Mark Tillack mentioned the UCSD group is considering the divertor T-tube optimization and how the tubes can be fabricated with the transition from tungsten to steel.
John Sheffield, who just joined the ARIES team, noted that charge-exchange erosion is a very important consideration and is quite critical in choosing in-vessel materials and configurations. To keep this erosion under control, the edge temperatures near a boundary need to be kept low. The reason is that, for hydrogen, the charge exchange cross section is 2-3 times the ionization cross section for T < 100 eV. Consequently, any neutral (particle) will have a high probability of charge-exchanging and hitting the wall with an energy up to 100 eV. This simple point assumes Te = Ti.
Somebody mentioned that it would be appropriate to consolidate this information and analyses into a paper for publishing in the FED journal.
Goldston noted that he thought the pilot plant he discussed in the December ARIES meeting could do the Demo mission to demonstrate the production of electricity with fusion energy.
Les Waganer and Tom Weaver noted they either have no budget or a very limited budget and they are waiting new funding to increase their technical contributions.