ARIES Documents -- Meetings ArchiveARIES Conference Call, 19 February 2013
Documented by L. Waganer
Previously, Mark Tillack posted a Doodle query about possible meeting dates late in May 2013. The team decided that the next project meeting will be held in the Washington DC area on Tuesday, May 21 (all day) and the half day of Wednesday, May 22, 2013. [Following the conference call, Les Waganer asked Al Opdenaker if he would agree to host the meeting in the DC area.]
The next ARIES conference call is scheduled for Tuesday, 19 March at the usual time.
Les Waganer said that he had integrated all the team comments on the draft minutes for the January project meeting and he would be sending out the final version the next day. [Done 2/13/13]
ARIES Technical Efforts
Materials - Arthur Rowcliffe said that he envisioned two approaches to document the materials issues with possible solutions: A) Have a stand-alone materials document that addresses the materials for all components or B) Create smaller material discussions for each major component, i.e., First Wall armor, Blanket structure, Structural Ring structure, Divertor structure and Vacuum Vessel structure. The team thought the smaller material discussions (1-2 pages each) integrated with those sections would be preferable. Related publications and documents could be referenced for more detailed, supportive technical information.
ACT-1 Final Report Technical Papers - As related to the prior discussion, Farrokh Najmabadi said that his list of paper titles is nearly complete, but he really needed the complete list of authors for each paper along with a brief synopsis of the topics to be discussed.
Systems Analysis - Mark Tillack mentioned that he would be on a business trip to Japan and China for about two weeks. The team should not expect any effort on the Systems Analysis task in the near future.
Laila El-Guebaly and Mark discussed whether the ARIES-CS DCLL radial build would be suitable as a starting point and they agreed it is reasonable, perhaps with a few minor changes. Laila presented at the January 2013 meeting an initial ACT-2 DCLL radial build, based on the ARIES-CS FW and blanket model. Laila mentioned an ARIES-CS first wall thickness of 3.8 cm He-cooled ferritic steel, but Mark thought that thickness would be excessive. Laila will investigate that first wall thickness and discuss it with Mark and the team for consideration. [Following the conference call, Mark examined the 3.8 cm FW and said it is a good start].
There was a discussion about when the preliminary ACT-2 baseline design values might be available and Mark said we should not expect such numbers until the May 2013 meeting. He and Chuck Kessel need to exercise the physics and engineering models before any credible design points can be determined.
Power Core Thermal Analysis with LOCA/LOFA - Laila and Carl Martin have been investigating several power core design variations to determine the inboard hot spot temperatures. Carl's reported result at the meeting was that the IB vacuum vessel reached 1150°C with the LOCA condition in the LT shield. If the WC filler of the IB LT shield is replaced with borated FS, the maximum structural FS would be lowered to 1080°C. Additionally, if the emissivity of the IB and OB first walls were changed from 0.2 to 0.9, the expected maximum structural temperature would drop to 950°C, which is below the 1050°C reusability limit for nano-clustered ODS FS. For this design to survive the worst case LOCA event, the IB SR, VV, and LT shield should be made of nano-clustered ODS FS. Laila asked if the inboard LiPb would be allowed to mix with the outboard LiPb. Mark responded the mix will take place in the outer coolant circuit. It was recommended that Carl Martin and Paul Humrickhouse discuss their models' groundrules to establish a common technical baseline.
Farrokh Najmabadi was also concerned that the 2D thermal analysis did not consider the cooling effects of the outboard vacuum vessel maintenance ports. Laila responded that in Carl's model the heat is removed by conduction and radiation from the outboard shield plug to port doors at 30°C. She will confirm with Carl on that issue. Carl is now working to integrate the afterheat input of the divertor into the LOCA analysis. Again, it was recommended the INL and UW analyses should be coordinated.
Laila reported that she will change the WC filler in the inboard low temperature shield to borated FS, which increases the inboard radial build by only 4 cm, and issue a revised IB radial build.
Power Core Safety Analysis - Paul Humrickhouse noted that he has revised the helium coolant system volume in his safety analysis per the January project action item. He is also analyzing the tritium retention in the vacuum vessel, with a new assessment of the vacuum vessel maintenance ports and cooled shield maintenance "inner doors".
Edge Modeling of Plasmas in Divertor Region - Marv Rensink reported new results on the plasma modeling with distributed impurities. Initally, they could not find any steady-state solutions, but with further investigation, they were able to find a few steady-state solutions. Perhaps with feedback control, steady-state plasma solutions can be maintained.
Power Core Design - Xueren Wang explained he has been collaborating with Chuck Kessel to locate and size the outer PF coils. Xueren has developed a new design for the PF coil system that is compatible with Chuck Kessel's analysis. The new outer PF coil is larger than the previous one. Additionally, the active feedback coil at midplane needs to be located closer to the plasma for improved performance.
Xueren has also been working on combining all the LH launchers and ICRF waveguides into a single sector as opposed to the previous design approach using two sectors.
Electro-Mechanical Analysis of Divertors - Jake Blanchard said that he had completed the draft of his final report section and would send it to Farrokh in the near future.
He noted that UW has incorporated the ANSYS model from UCSD that included the plasma chamber and the PF coils. He is conducting a more detailed EM analysis of a quenched plasma current that is transferred to the plasma chamber (power core) conducting elements.