ARIES Documents -- Meetings ArchiveARIES E Meeting, 7 September 1999
Documented by L. Waganer
The dates of the next ARIES meeting were selected to be 1 December starting at 1:00 p.m. through noon of 3 December (Wednesday through Friday). Separate meetings for the physics and engineering groups will be held on Wednesday afternoon. The next project e-meeting will be held on 7 October at 9:00 to 12:00 PDT. Les Waganer will obtain a conference call number and Mark Tillack will handle the Web inputs. It was also suggested that the Engineering group hold a short meeting at the October SOFE meeting - L. Waganer offered to inquire about room availability.
Bill Dove noted there are no indications as to wording or funding contained in the current fusion budget bill. There is talk of a continuing resolution. DOE has prepared budget cases for several scenarios. He suggested that we might have either the same or slightly lower budget for the Advanced Design Studies group. There is a lot of interest in transitioning most of the engineering team over to assess the engineering of IFE concepts. Stay tuned for the final budget amount and direction. .
Neutron Source Study
Don Steiner summarized the work accomplished and the near-term actions to be accomplished on the Neutron Source Study. Les Waganer is to write up the tentative applications, the evaluation process, and the selection of the applications to be studied in more detail. Ron Miller is comparing several fusion options; namely, a driven subcritical plutonium reactor to burn plutonium and produce energy and a transmutation reactor for nuclear waste. (This will be compared to the accelerator approach.) For the plutonium reactor, Ron is adapting the ARIES-ST database to create a baseline for comparison. This baseline will be a physically smaller machine with higher neutron multiplication and lower wall loading for the nominal 1000 MWe output. The problem is this approach extrapolates the existing systems code modeling to the limit. Ron is contacting team members to verify the extrapolated data. He is hoping to publish a strawman shortly for consideration and evaluation. C. Kessel questioned the extrapolation of the systems code physics database to such an application.
Mark Tillack is assembling technical data on the ATW to be used in a comparison between fusion and accelerator approaches. He has found four blanket concepts in the accelerator and fission communities for use in this comparison study, two of which were mentioned: GA has a MHTGR (Modular High Temperature Gas-cooled Reactor?) approach and Cheng has an MHD approach. Mark is also hoping to publish the data table shortly.
Plasma Physics (Advanced ARIES-RS)
Chuck Kessel has been focusing on stability studies on plasma elongation and triangularity. Specific topics being investigated were the location of the stability shells, use of tungsten conductive shells for vertical stability, design of the control coils, and impact of these factors on plasma beta. Laila proposed to move the W vertical shell closer to the plasma and place it between the two outboard blanket segments to improve the physics (higher elongation and higher beta). The range of elongation values being considered are from the present 1.8 up to 3.0 with an aspect ratio of 4. Over this range, the beta normally peaks around an elongation of 2.4. Above an aspect ratio of 4, the conductive wall location is more critical. One favorable case he evaluated was an elongation of 2.4, betaN of 7.1, plasma current of 21.8 MA, and a beta of 14%.
TK Mau is evaluating the RF current drive system requirements for the ARIES-AT. He has been concentrating on the effect of the plasma edge density on the current drive system. DIII-D had some experience on operating different current drive (CD) systems with a non-zero edge density. TK is trying to determine a scaling law to predict current drive power and efficiency for various classes of CD systems.
Laila El-Guebaly noted she is defining the design basis for the ARIES-AT, but continues to need critical data to complete the basis. The SiC burnup limit has been nominally defined as 3%, but this limit should be affirmed as the best approximation given current database (action: Mike Billone.) There are two inboard shield candidates for consideration: a high performance design using tungsten carbide filler and a more typical, all ferritic steel design. The WC-based shield/VV is 15 cm thinner than the FS-based shield/VV Les Waganer is to develop a cost estimate for these two approaches. UW has recently included the "clearance index" for all isotopes (received form D. Petti) in the ALARA activation code. The clearance index will be computed for all the in-vessel components of ARIES-AT.
Rene Raffray reported a convergence of the blanket and coolant approaches being proposed by UCSD and UW. The use of helium in the FW and blanket should be avoided to eliminate pressurization of the blanket by high-pressure helium. A new LiPb-cooled first wall is being evaluated as a possible alternative. The net thermal conversion efficiency for both He-cooled and LiPb-cooled FW approaches is similar.
Mark Tillack is working on a liquid metal divertor similar to that proposed by ALPS. Rich Mattas and Jeff Brooks of ANL are advising Mark on the ARIES divertor design. The upper divertor is difficult to design with a liquid metal; therefore, the plasma probably would be biased to have most of the particle and heat flux on the lower divertor, with a more conventional, lower capability approach on the upper divertor region.