ARIES Documents -- Meetings ArchiveARIES Conference Call, 19 July 2000
Farrokh Najmabadi has received several recommendations for the September meeting dates. The possible dates remain the four mentioned during the June meeting and in the notice of this conference call. Farrokh has to verify a few final arrangements and hopes to confirm the date by the end of this week.
Les Waganer suggested we select a date for the August conference call. A consensus was reached on Tuesday, 22 August. [Les Waganer has obtained a number of 314-232-3805 @ 9-11 PDT.]
L. Waganer noted that the draft June ARIES meeting minutes have been distributed. He is waiting until one more input is received and hopes to release the final version next week.
Farrokh has not formulated and distributed the draft ARIES-AT final report outline. He said he would send it out by the end of the week.
Target and Chamber Physics
Bob Peterson said that he had been talking with Andy Schmitt to obtain the target physics data to run the BUCKY code and determine x-ray and debris output (to include both spectra and magnitude). Results are expected in a week or two. The target design is the DD target with a gold coating and wetted plastic foam layer. Bob will also compare results with LLNL predictions and post the results on the UW web site.
[From a later discussion in the call] Wayne Meier said he has some preliminary gain curves and believes he will be able to generate gain curves for all the candidate laser target concepts. He said Debbie Callahan-Miller should also be able to supply the ID HI gain curves as a function of spot size and beam energy for the distributed radiator and the closely coupled radiator. Wayne will try to serve as the focal point for the gain curve generation.
Don Haynes is working on chamber opacity with a range of xenon pressures from zero to 1.0 torr. He will be determining the mechanical and heat loading on the first wall. After he assesses this range of variables is considered, he will investigate krypton as the attenuating gas.
Chamber Wall Engineering
Mark Tillack has been conferring with Jeff Brooks on the erosion and material transfer from the wall to colder surfaces. Dai-Kai Sze is also working with Jeff on this subject.
Chamber Nuclear Analysis
Laila El-Guebaly is working on the list of initial parameters to be supplied to all the people working on nuclear analyses and those receiving the results. It will be sent out in a week for comment.
No action reported.
Mark Tillack has met with GA to establish an R&D plan to develop and protect final optics. This mostly pertained to laser optics, but it was recommended that the investigation be expanded to HI.
Target Fabrication, Injection, and Tracking
Ken Schultz informed the group that Roger Bangerter would like for us to consider a HI direct drive target in the dry wall chamber. He plans to meet with Roger to obtain the necessary data. Ken mentioned that he thought the laser and HI DD target performance, spectra, and debris would be similar; but Wayne Meier thought the converter materials cause a significant difference. Bob Peterson volunteered to evaluate the HI DD target data in his analyses.
Simon Yu asked if all target and driver options are to be assessed for all chamber concepts. Farrokh Najmabadi affirmed all options should be kept open for assessment. Simon noted that it is not just the influence of the targets, but subsystems, such as the final optics, may have a significant influence on the chamber concept assessment results.
Dan Goodin reported discussions with NRL to determine potential target improvements. He is working with the target designers to evaluate the delivery and survivability of the target. A principal goal is to eliminate or significantly reduce the chamber gas. Polymer thicknesses from 1 micron up to 5 microns provide no significant reduction in the heat transfer to the DT ice. However, polymer thicknesses of 100 microns or more could provide thermal improvement. Both the radiation effect from the wall and the convective heating from the chamber gas are being evaluated. The current results indicate that a number of changes would be required for survival of the NRL radiation-preheated target to survive in the chamber. These changes are: (a) the gas must be essentially removed, (b) the chamber wall must be operated approximately 200°C cooler, and (c) a target surface reflectance of 98% in the IR must be obtained. The feasibility of fabricating such a gold layer to obtain this reflectance (98%) is being tested.
Dan also said that he is assessing protection schemes for the DD targets, including the precursor frozen gas pellet and the sacrificial injection tube that Igor proposed at the ARIES June meeting. Preliminary results indicate significant heating within the tube, similar to heating without a tube. Laila noted that Igor Sviatoslavsky is working on an improved, cooled version and will soon send that definition to Dan and other interested people.
Art Nobile said they were working on the ID target fabrication processes. The necessary processes are understood for the capsule and need to be scaled up to production capabilities. A flow sheet code is being used to simulate the production processes.
Ron Miller is assessing what can be salvaged from prior IFE system assessment codes from the Schaffer Corporation and The Boeing Company. Additionally, he is working with Steve Payne of LLNL to transform existing DPSSL models into something useful for the system code architecture. Ron anticipates bringing the code and analysis tools up to current state of the art.
Les said he has circulated for review a draft definition of the groundrules, architecture, system and subsystem options and subsystem parameters to be used to define and assess the system options. Ron then discussed the concept of design windows (multi-parameter space) to assess the more feasible system options and related parameter spaces. He also anticipates analyzing and reporting the system uncertainties.
Safety and Environmental Analysis
Dave Petti reported he has been talking with Jeff Latkowski about the oxidation of the carbon/carbon first wall surface on the dry wall chamber concept, ala Sombrero. They are trying to assess the accuracy of the simulation model.
Chuck Kessel told the group that when the feedback control system is used, the plasma does not require an induced plasma rotation for a stable plasma configuration. Ming Chu (sp?) of GA will confirm this conclusion.
Chuck also mentioned that he developed a plasma configuration that improves the off-axis RF current drive efficiency. The plasma profiles are shifted outboard and squeezed. But TK Mau noted this configuration is better but not exactly correct yet. The prior configuration was at 25% and this one achieved 6-10%. Chuck said he would develop one final configuration to obtain a better result.
TK Mau is working on the definition of the RF launchers. Meanwhile GA is determining the startup RF power requirements that will impact the size of the launchers.
[I may need some help getting this one right]. GA is working on modeling and analyzing the AT divertor. Rene mentioned that he attended a meeting at GA and left with the impression that the divertor was radiating an unacceptable amount of power to the local first wall. Farrokh noted that the divertor approach GA proposed in the June Madison meeting would not work and should not be considered. GA is now working on an argon-radiating mantle. There are also problems with the current approach. Farrokh took the initiative to have a meeting with Tom Petrie to agree upon divertor approach and guidelines.
Les Waganer mentioned that Laila had recommended a recessed weld joint for joining the field assembled vacuum vessel components on the spool assembly (inboard and divertor regions). This design is recessed to offer the weld sufficient protection to be rewelded within the nominal service life. Les is preparing an assessment of the fabrication and operational benefits of this approach and will send it to Laila for review and comment.
Les noted he soon would start the maintenance and availability assessment. Ron also noted that he could do the parametric evaluation independently of Les’ work.
Tom Brown said he was waiting to send ProEngineer models back to UCSD until they updated their ProEngineer to the latest, compatible version. However, UCSD will not soon upgrade their CAD software. PPPL will check with the supplier of ProEngineer to determine if UCSD can either use the PPPL software under an extended license agreement or if a translator is available.
Fred Dahlgren mentioned that he has been stiffening the outer TF coil cases to reduce deflections below limits. The width of the removed module is the main geometry constraint. After he has a suitable solution, he will finalize the TF and PF coil designs.
Laila El-Guebaly said she had posted on the UW web the revised radial build data sets that contained the new stabilizing and resistive wall mode shells. The blanket thicknesses changed only slightly. She noted Paul Wilson plans to finish the activation analyses by the end the week.
Dai-Kai Sze said that he had been talking to Ed Cheng about the processing of polonium. Laila mentioned that the Po and Bi inventories for the ARIES-AT design are posted on the UW web site. Dai-Kai hopes to complete the tritium inventory assessment by the end of the week.
Ron Miller discussed the ability to parametrically assess the impact of variable plant factors (availability). He has obtained the new radial build but has not incorporated it yet. Neither has he incorporated the new cost of the vacuum vessel. He is waiting for the new physics and the RF design and physics basis. Chuck Kessel noted the physics changes would be minimal.
Safety and Environmental Impact
Dave Petti said they are calculating the plant tritium inventory, especially the tritium tied up in plant materials. He is estimating about 150 grams of tritium would be co-deposited on cooler reactor surfaces. There are also about 100 grams in the SiC, but that tritium is bound more tightly and is not easily mobile or releasable. Laila has some relevant data about tritium contained in SiC from nuclear reactions and she will forward the data to Dave Petti.