ARIES Documents -- Meetings ArchiveARIES Conference Call, 11 July 2001
Documented by L. Waganer
Farrokh Najmabadi discussed the date for the next ARIES meeting as being associated with a High Average Power Laser Workshop to be held in LLNL. The dates for both meetings have not been coordinated or set, but the dates will likely be in October 2001.
Les Waganer prompted the group to set a date for the next conference call. It was established as 15 August 2001 (Wednesday). Les will arrange for a conference call number.
Abstracts for the upcoming SOFE conference need to be submitted ASAP.
Ron Miller said he and Rene Raffray are defining the overlapping parameter space regions that offer viable design and operating solutions for the HI and laser IFE systems. Ron and Rene have been modeling the driver power requirements with supplied net driver efficiencies (HI is 30% and KrF is 7%) and a fixed recirculating power fraction. The assumed thermal conversion efficiency is 55%. The resultant net electrical power will not be at the desired 1000 MWe, but the results can be scaled upward to the desired output by changing the repetition rate. The target performance is being used at the ìkneeî of the gain curves, above which the performance slowly improves. Ron said most of his data is on the ARIES web and he will add all the contentious data as well for examination..
Chamber Wall Engineering
Rene Raffray completed (and distributed to the team) a set of drywall chamber design parameters, materials, designs, and operating conditions for the DD and ID targets on an Excel spreadsheet. Rene noted he had difficulty to satisfy the SiC/SiC temperature limit of 1000ƒC due to the high heat flux on the chamber wall (~ 2 MW/m2) and corresponding high DT through the wall. As noted earlier, the most likely parameter to change to achieve the desired net power is the repetition rate, but that exacerbates the heat flux problem. The other option is to increase the chamber radius, perhaps from the 4.5 m range up to something around 5.5 m. Rene mentioned a relationship between chamber radius to thermal cycle efficiency (maximum coolant temperature). Les Waganer suggested another option is to use multiple chambers to lower the effective repetition rate and the chamber radius (although this might not be most economic approach).
Ron Petzoldt noted that a larger (5.5 m) chamber radius would require lowering the wall temperature from 1000ƒC to about 950ƒC to avoid excessive target heating.
Laila El-Guebaly relayed information from Don Haynes and Bob Peterson that they are documenting the dry wall chamber physics results and doing calculations for the point design. They hope hoped to send these results to Rene for use by the end of the week (20 July 2001)
Chamber Nuclear AnalysisLaila El-Guebaly has been documenting the nuclear analysis and results for the dry wall design. She sent the nuclear data for the point design to Rene. Data includes tritium breeding ratios, nuclear wall loading, and FW volumetric heating.
Drivers and Beam TransportSimon Yu told the group that he had been working with Tom Brown of PPPL to define the vacuum pumping systems for the final focus region (sizing system parameters, location of pumps, sensitivity to size of pump port openings). The initial results indicate the prior assumed port channels should be reduced from 5 cm radius to 2 cm radius to achieve a more reasonable solution.
Final Focus Element ProtectionTK Mau has been investigating the combination of Spinel applied over SiC, proposed by El-Guebaly at the June ARIES meeting. However, the combination of Spinel/SiC is predicted to have a reflectivity around 90% while it is desired to have 98-99% reflectivity. Replacement of SiC with CC raised the reflectivity up to 92%, which is not enough of an improvement. TK will now address alternative solutions, such as Spinel over Al and a liquid coating. [Suggestion by Les. Could you consider Spinel over a thin Al coating and a thicker SiC base? This combines good reflectivity of Al and then neutron resistance of SiC.]
Off Normal Event AssessmentDon Steiner noted that Ken Schultz led a tour of a small ARIES group through GAís target production facility after the June ARIES meeting. This provided an insight as to direction toward commercial production and how much is to be accomplished to ultimately achieve a high quality, high quantity production facility (no negatives intended, just that there is a lot left to be done.) Don Steiner emphasized that he and the team are trying to estimate the frequency of the off-normal events and the consequences. Dave Petti and Lee Cadwallader are organizing a fact-finding trip to Micron chip factory to infer the quality processes and data that might be related to commercial target production. GA wanted to be involved in this meeting - Dave noted they are involved in the process. Ron Miller is pursuing the quality of the process of minting coins.