ARIES Documents -- Meetings ArchiveARIES Conference Call, 29 September 2011
Documented by L. Waganer
Les Waganer affirmed the next ARIES meeting will be on October 13-14, Thursday and Friday at the Hilton Washington DC North/Gaithersburg Hotel, 620 Perry Parkway, Gaithersburg, MD conference room TBD. Al Opdenaker has made arrangements for reasonable room rates of $149/night - ask for "Systems Studies" at 301-977-8900 (direct) or 1-800-445-8667.
Several people might participate in the October meeting via phone, including Arthur Rowcliffe, Marv Rensink and perhaps Tom Weaver. Les Waganer mentioned that a speaker phone will be provided by Al Opdenaker and the normal conference call in number will be used for the project meeting.
ARIES Project Direction
Farrokh Najmabadi emphasized the need to finalize the design point for the aggressive physics/aggressive (SiC blanket) technology case. Les Waganer asked if the conservative physics/aggressive technology case would also be finalized at the meeting and Farrokh said the number one priority would be on the aggressive physics/aggressive technology, but the conservative physics database is being developed and may soon be ready for issue.
ARIES Technical Efforts
Tom Weaver reported that I-Li Lu (of Boeing) has been populating the reliability prediction model of the ARIES-ACT outer divertor with parameters provided by Tom. The intent is to model the effects of ELMs using the baseline energy flux.
Dale Meade asked where the ARIES-ACT baseline strawman could be found. Mark Tillack said the April 2011 strawmen are located on the ARIES home page website, Systems Runs - Strawmen.
Minami Yoda noted that the GT group is carrying out experiments with helium on the finger-type divertor and will be reporting their initial results in the October meeting.
Tom Rognlien said that they have been working on the divertor region modeling handling the existing divertor heat load model. The results are indicating an excessive heat load (~ 25 MW/m2) for this preliminary divertor case. This should not be considered as a final case; rather they are trying to make sure the model is correctly modeling the physical conditions. They have added a diagnostic algorithm in the code to indicate the heat load on the dome. Mark Tillack asked what inclination the plates were to the separatrix field lines and Tom R. thought it was about 25° and noted that reducing the angle would indeed reduce the heat load, but the plasma might become non-steady state. ITER currently has their divertor at a small angle to the separatrix field lines. Tom and Marv are also investigating other impurity species and levels to mitigate the heat load. This topic will be extensively discussed at the October project meeting. After the divertor region physics are better understood, optimization of the heat loads can commence.
Lane Carlson said that he had issued the SiC strawman in April 2011 and has been working to complete the DCLL module to enable the completion of the companion DCLL strawman. He has also been working with Mark Tillack on the improvement of the power balance and documentation. It has been difficult to validate all the power balances in the plant and make sure they are properly documented (e.g. naming nomenclature).
Xueren Wang has been working on the ARIES-ACT power core configuration design with Mark Tillack and Siegfried Malang. Xueren is basing the design on the ACT-1b aggressive physics case of June 8, 2011, which essentially has the same physics as the April 2011 ACT-1 case. Specific geometry definitions were provided by Chuck Kessel. Xueren presented two design options, differing in either LiPb or helium coolant in the IB and OB shields. Xueren provided more design details on the LiPb option including plumbing routings. The second option remains in work. There was a question about a possible conflict between the ARIES-AT TF structural cap and the vacuum ducts. The ARIES-AT CAD drawings indicate a cutout in the cap for the vacuum duct; see ARIES-AT Fusion Power Core drawings. However, this cutout may not have been analyzed. It was suggested to provide a viewgraph of the structural cap issues and remaining analysis to confirm structural approach at the October meeting.
Mark Tillack noted that a lot of design and analysis effort is underway to minimize the MHD pressure losses in the manifolds and piping. Mark presented several CAD drawings of LiPb headers and piping arrangements to help reduce the flow velocity and resultant MHD pressure losses. See the links to the drawings in the ARIES Document archive of meetings and calls, Sept 29, 2011 Conference Call. This topic will be presented and discussed at the October meeting. Siegfried will compare this one with his original concept.
Laila El-Guebaly mentioned that the exit temperature of the LiPb will likely be reduced from 1100°C to 1000°C, which, along with the use of helium to cool the shield and divertor, will then reduce the thermal conversion efficiency below 60%. The shield helium coolant loop will be utilized to preheat the He coolant of the divertor. Laila will not have any results to present at the meeting, but the technical decisions at the meeting will enable Laila to begin to analyze the new baseline cases and issue a new radial build.
Jake Blanchard has been updating the fracture mechanics analysis to provide a higher fidelity result than the 2D analysis. The 3-D analysis looks better. He did a literature review for the tungsten of the divertor and ran some preliminary ANSYS analyses. Also, he has been reviewing the ITER VV mechanical loads for applicability to the ARIES vacuum vessel loads analysis.
Laila El-Guebaly has been working on her action items. She has begun defining the SiC radial build for the aggressive technology baseline, but she is awaiting some final decisions from the October meeting. She has documented some of her analysis and results for the 3-D TBR and VV activation and will post them on the University of Wisconsin-Madison web site. She noted that there is some analytical evidence of the SiC flow channel insert may degrade in the likely neutron environment of a tokamak power plant. The alumina insert material may be acceptable - Laila is following up on this latter point. Arthur Rowcliffe noted that there is a lot of irradiation testing on ceramics for use in fusion reactors.