Thrust 12 12.001 Jarboe Tom 6/08/2009 11:29 Thrust 12 Needs a comment, on the first page, on theme 12s relation to 9, 10, and 11 as Mike explained in his talk. 12.002 Hill David 6/09/2009 10:07 Thrust 12 This thrust seems to overlap nearly completely with core-edge coupling part of thrust 8. The combination of these two thrusts seems to imply that two separate experiments are needed, both with high confinement neutron-producing cores (either by short pulse DT or longer pulse DD operation) and appropriate PFCs. Is this what we mean? 12.003 Hill David 6/09/2009 13:38 Thrust 12 With regard to long-pulse component reliability, there has been a lot of mention of experience from Tore Supra regarding development of hot spots and ultimate component failures. As I recall, these were due to undetected defects in fabrication, rather than unexpected heat flux. These undetected defects came to light only gradually, perhaps due to gradual delamination of components. Such failures were attributed to inadequate pre-installation qualification. Thus, it would seem that off-line testing/qualification is more relevant than testing in tokamaks. 12.004 Callis Richard 6/09/2009 13:44 Thrust 12 How do you account for edge Alpha affects on PFCs if you do not run in DT? 12.005 Marmar Earl 6/09/2009 13:48 Thrust 12 Liquid lithium is mentioned as a possible plasma facing material. However, in the stated temperature range (500 to 1000 C), the vapor pressure of Li is very high (around 50 torr at 1000 C). Is liquid Li a credible option for the proposed facility (and by extension for DEMO or a reactor)? 12.006 Hill David 6/09/2009 13:53 Thrust 12 Won't the integrated testing require a high confinement core plasma? Is this compatible with hydrogen operation? Won't it have to have same kinds of ELMs and edge pedestal and core transport as high confinement plasmas in order to validate the integrated operation? If so, won't this mean DD operation and subsequent neutron activation? Are there agreed upon (but fusion power proponents) possible solutions that will be tested? If not, does it make sense to begin design of such a facility now? 12.007 Taylor Tony 6/09/2009 13:54 Thrust 12 CLARIFICATION I understand that the facility called for here is primarily a "integration" facility. New materials and there properties will be developed in 10, optimial configurations will be developed in 11, and ELM suppression will be perfected in 2. Do these other activities precede thrust 12 - Does 12 need to wait on these other tasks? 12.008 Buttery Richard 6/09/2009 15:36 Thrust 12 Absence of DT option seems puzzling. Logic of previous thrusts is that dpa may change the materials properties, therefore it seems odd to start by ruling out any kind of D-T phase – particularly when the device will need remote handling. Surely should retain an option on some kind of DT phase? Your argument seemed to be about need for shielding for high fluence operation could be constraining. But even in D-D you will need R-H, and machine will make T as well, which needs handling. 12.009 Buttery Richard 6/09/2009 15:37 Thrust 12 Please define how far this thrust goes beyond what can be achieved in Asian devices (up to 100s, metal walls). How crucial is the extra bit. 12.010 Navratil Jerry 6/10/2009 08:44 Thrust 12 This 'integration' thrust assumes that PMI effects are separable from effects of nuclear damage - but data shown in presentations of Thrust 10 and 11 indicate this is not correct. The surface and material characteristics of the PFCs are strongly affected by neutron damage. 12.011 Garofalo Andrea 6/10/2009 09:52 Thrust 12 Thorough integrated testing would seem to require testing the effects of DEMO-level neutron damage, therefore requiring operation with a high performance DT core. Then, this thrust looks a lot like the first stage of a Thrust 8 facility. Flexibility and ease of maintenance already must be included in a Thrust 8 facility design. The perturbation to Thrust 8 from including Thrust 12 seems minimal. 12.012 Meade Dale 6/10/2009 11:19 Thrust 12 The terms Demo-relevant, Demo-like are used to describe the regimes of interest for this thrust. What is meant by Demo-like? It seems that only the power density is Demo-like. There are numerous other important physical variables: pedestal temperature and temperature, scrape-off temperature and density, scrape-off width and length, collisionality at the pedestal and in the scrape-off, geometry and mirror ratio in the scrape-off for parallel transport, fuel species mix, etc. Are these additional parameters Demo-like? Demo-like for the edge core coupling implies a Demo-like core – are the ρ∗, ν∗ and β in the core similar to Demo? 12.013 Meade Dale 6/10/2009 11:23 Thrust 12 The term high performance is used to characterize the plasma condition needed to address this thrust. High performance has two parts – high confinement (ntau for high Q) and high power density(beta^2B^4). Are both needed to address this thrust? 12.014 Peng Martin 6/10/2009 15:43 Thrust 12 This chit is put in now, as suggested by the leaders of the Thrust 12 discussion. Thrust 12 should have adequate clarity regarding the uncertainties of success of an integrated PFC solution obtained using a DD toroidal facility, when it is operated in a full fusion nuclear environment for the first time. Examples of potential or likely failure include: The synergistic radiation induced interactions of combined materials in a PFC under expected full operating conditions, which is identified in thrust 14 as a critical research contribution enabled by thrust 13. Thus, a worthy PFC, be it born of thrust 12 or other research thrusts, will have to be tested and its likely failure mechanisms discovered and understood, solutions developed (or re-developed), and re-tested in a full environment. 12.015 Peng Martin 6/10/2009 16:06 Thrust 12 Thrust 12 needs to be clear regarding the research capabilities required to carry out the research promised. An example: Thrust 12 promises the capability of delivering 10^6 s accumulated plasma operaton under high heat flux toroidal integrated high confinement conditions. It therefore require a divertor that are proven to survive 10^6 s total operation while handling a peak heat flux of 10 MW/m2 or higher, to begin the promised research in thrust 12. Thrust 12 therefore needs to be clear about requiring such divertor solutions, as an example, perhaps born of other thrusts, to deliver on its promises.