ARIES Documents -- Meetings ArchiveARIES Conference Call, 13 January 2004
Documented by L. Waganer
Les Waganer said there are a few people have a conflict with the proposed date for the next meeting in San Diego during the first week of March. It turned out there is a serious conflict, so the following week is being considered. The Team decided to hold the next ARIES meeting in San Diego on Monday, 8 March (all day) and Tuesday, 9 March (morning only). This will allow participants to make flight connections Eastbound.
The next meeting is scheduled for June and Laila El-Guebaly graciously offered to host the meeting at the University of Wisconsin – Madison. The proposed week of June 7 through 11 does not work for Laila as she has a conflict that entire week. The following week is better for Laila, but there are several other conflicts. The better choices are Tues-Wed, 15-16 June or Wed-Thurs, 16-17 June, both with the second day only a half day for flight connections. Les Waganer will again poll the Team to determine the better of the dates.
Status of ARIES-CS Action Items Identified in December 2003 Meeting
Plasma and Coil Optimization - Long-Poe Ku said he had provided the code to T.K. Mau and the coil data to Laila El-Guebaly. He has been defining the alpha loss on the first wall. He established a thin (5 cm) pressure-less layer just outside the last plasma surface to determine the equilibrium conditions and alpha loss at that layer interface. As expected, the alpha loss values obtained were nearly identical to those associated with the plasma last closed surface.
He is also searching for different “attractive” plasma-coil configurations. As he mentioned in the December 2003 meeting, he is trying to avoid resonance-generated instabilities. He has found some combinations with good QA symmetry, but has not determined the coils. He will report on his findings at the March 2004 meeting.
He is working with Paul Garabedian to obtain consistent VMEC data for the two-field period configurations.
Physics Assessment of a Two-Field Period Reactor – Paul Garabedian considered the engineering data provided by Laila El-Guebaly. He is considering increasing the radius of the two-field period machine from 6 m to 7 m to ease the blanket thickness constraints and the maintenance accessibility. He has been examining older cases he assessed in the past and has found several that are worthy of reexamination for use in the ARIES-CS assessment as they have quite good coil configurations. Paul was anxious about the use of higher fields and the cost consequences of using high field magnets. Leslie Bromberg explained he presented relevant data that Paul could use and said that he and Paul would collaborate on Paul’s concerns and use of high field superconductors.
Superconducting Magnet Data – Leslie said he has been developing a spreadsheet of the low and higher temperature superconductors that might be of use to the CS machines. He still needs to develop performance and cost data on the magnet cyrosystems for the low and moderate temperature operating conditions. Upon completion he will send the data to the engineering and physics team.
Divertor Engineering – Said Abdel-Khalik stated that he and his team are looking at possible divertor designs that might be used in the CS design. He is using a MERLOT (Spelling?) to evaluate the concept performance. He is also considering liquid film divertor design approaches. The surface temperature limit is based on evaporation rate. The temperature gradient within the film is also a limiting condition. Film thickness is one critical parameter to be traded to optimize the design approach. With liquid films, the magnet field structure is important to the operation of these films. LLNL may help with the calculation of the distribution of the magnet fields in the divertor regions.
Don Steiner mentioned he has a new physics student that is involved in the design and performance of diverters in stellarators. He will see if the student can help our project in this area.
Power Core Engineering – René Raffray reported Xueren Wang has been generating 3-D structures for the CS coils defined for the three and two-field period coil geometries provided. He has also been providing additional fidelity on the blanket geometries where the blanket sectors are removed by sliding blanket modules in the toroidal direction. This improved fidelity will enable the determination if the blanket modules can be removed as they are presently configured or if they need to be sculpted to eliminate the interference.
René mentioned Said’s work on the divertor subsystem with several possible approaches to be investigated. The MERLOT code would be used to scope the approach capabilities.
René noted that Sigfried Malang is analyzing the ceramic breeder blanket to determine the failure modes of the helium coolant system to overpressurize the blanket wall causing a rupture and system breech. They may need to redesign the blanket to minimize or eliminate the overpressurization condition.
Neutronic Analysis – Laila El-Guebaly is working with Paul Garabedian to determine the potential breeding capability on the two-field period design. It is likely the TBR is low for the present design and will need to be increased to the normal design value. A solution may be to go to Flibe with Be or increase the effective blanket coverage (minimal or no shield-only regions).
Laila is starting the activation analysis for the CS reactor strawman conceptual approaches. She will evaluate the medium temperature superconductor suggested by Leslie Bromberg, probably MbB2 and compare the results to the low temperature superconductor case.