ARIES Project Conference Call

12 November 1997

Documented by L. Waganer



Participants:
(DOE) -
(UCSD) Mau, Miller
(PPPL) Jardin
(GA) -
(UW) El-Guebaly, Khater
(FPA) --
(RPI) Steiner
(ANL) -
(Boeing) Waganer

Administrative

Les Waganer noted that the 22 October conference call minutes have been distributed and M. Tillack will post them on the Web site shortly (done 11/12). The next conference call is scheduled for 3 December 1997.

L. Waganer is assembling the 9th Progress Report and should distribute the draft shortly. M. Tillack will be collecting the ARIES SOFE papers for distribution as a package.

Ron Miller noted that Ian Cook intends to issue in December a formal announcement for the IAEA Technical Committee Meeting on Fusion Power Plant Design to be held in Culham in March 1998. The 13th ANS Topical Meeting on the Technology of Fusion Energy is scheduled for June 1998 with summaries due on 9 January. Please review these suggested topics for these meetings with discussion during the December conference call:

ARIES-ST Power Plant OverviewNajmabadi
Summary of Plasma Physics Operating RegimesJardin
Proposed ST Current Drive OptionsMau
Evolution of ST Designs from Experiments to Power PlantsStambaugh
Economics and Performance of an ST Power PlantMiller
Overview of ST EngineeringTillack
An ST Configuration for Improved MaintenanceWang
ST Center Column Design OptionsReiersen
ST First Wall and Blanket EngineeringSze
Neutronic Performance of ST Blanket Options El-Guebaly
3-D Neutronics Study for an ST Power Plant El-Guebaly
Necessity of Inboard Shield for Center Post Protection of ST Power Plants El-Guebaly/Khater
Safety Issues for ST Power Plants Khater
LOCA Analysis for ST Power Plants Mogahed
Innovative ST Divertor ApproachesTillack
Review of Alternate Fusion ApplicationsWaganer

Plasma Physics

Steve Jardin noted that work is progressing in two areas. The vertical stability codes are having difficulty converging on stable solutions. The TEQ code, developed at LLNL, cannot converge on LAR solutions. The Nova-W code might converge, but the code has problems running and the developer is no longer at PPPL. He has been contacted to return to help debug the code. The third code is the TSC code which does converge, but requires a very long time to reach stable solutions. The problem is not perceived to be the physics, rather it is the convergence algorithms within the codes and the initializing data selection. The aspect ratios susceptible to poor convergence are across the spectrum of data being considered.

PPPL is determining the plasma stability limits when no conducting wall is present. The beta limits in these cases are anticipated to be low. But these cases should be examined to determine the impact of having or not having the conducting wall. Ron Miller agreed to evaluate such cases with the ASC code to quantify the effect. Input data will be provided after the upcoming APS meeting.

TK Mau has completed his two SOFE papers on ST current drive options. He is presently preparing his paper on High Harmonic Fast Wave Systems for NSTX and ARIES-ST for the APS meeting next week. He is still strong on the capability of NB to provide on-axis CD. Laila asked if TK would recommend an outboard wall coverage for RF systems, but he felt it was premature at this point (resolution is scheduled for the January meeting). However, he did think that the 1% of the outboard surface area assumed by Laila was inadequate. [Mark, for the strawman, perhaps we should bump up the allocation somewhat?]

Engineering

Nuclear Parameters and Radial Build - Earlier this week, Laila El-Guebaly provided the team with a summary of the ARIES-ST nuclear parameters for all the materials employed in the power core and the assumed radial build. Laila highlighted the assertion of Sze and Malang that the LiPb/FS/SiC/He outboard blanket is limited to 5 MW/m2 (peak) [note: the latest strawman has the peak wall loading of 8 MW/m2]. R. Miller questioned why the limiting wall load was reduced from previous designs, but L. El-Guebaly, et al replied that the more capable wall and blanket approaches previously employed were based on a lithium/vanadium design. The choice of LiPb/FS/SiC/He was determined for safety reasons coupled with the selection of water in the center post (and elimination of lithium as a blanket coolant). If we, within our group, are questioning our rationale and findings, we must clearly document the reasons, rationale, and findings because this finding will be questioned by the fusion community at large.

Center Post - Don Steiner mentioned that W. Reiersen has been fully occupied by K-Star activities and has not been able to work on ARIES-ST design.

Configuration and Maintenance - Ron Miller noted that X. Wang and F. Najmabadi documented the recommended ARIES-ST vertical maintenance approach in their SOFE paper.

Safety Studies (LOCA) - H. Khater reported that E. Mogahed has completed a LOCA analysis which updated the heat transfer mechanism from the inboard shield to the copper centerpost. Previously it was purely radiative. He modified the code to add a conduction term equivalent to 1% steel conductivity. The results for 2.5 MW/m2 average inboard neutron wall loading are:

Initial TemperatureRadiation Transport Conduction TransportMaximum Temperature
500oYes0%900o
500oYes1% of Steel650o
300oYes0%870o
300oYes1% of Steel 450o

Systems Studies

Ron Miller informed the group that W. Reiersen provided the breakout of the heat loads assumed on the K-Star reactor for comparison with the ARIES-ST strawman. C. Bathke also sent the LANL POPCON code to Ron for use in the systems analysis work. Ron is working on verifying the joule losses in the centerpost and revising the centerpost and divertor regions to better model the evolving engineering design. He also has been corresponding with Dr. Seki on a task to model or evaluate the socio-economics for fusion power systems.

Alternate Applications

Les Waganer has just completed a draft of an article for the ANS-FED Newsletter explaining the Alternate Applications study scope, candidate products, assessment methodology, and preliminary results. In early December he is to confer with Dr. Terry Bahill of the University of Arizona who is the author of the Decision Analysis book reviewed in the September PPPL meeting. The purpose of the meeting is to help refine the assessment methodology.