All Themes Chits 02.001 intrator tom 6/08/2009 10:54 Theme 02 the level of discussion thus far (through thrust 2, and what I have seen from thrust docs) is mired in mind numbing detail. The only one that seems close to ready to be massaged into a document that the layman could comprehend, is the RFP one. The science is mingled with the engineering, which is logical. However the excitement needs more effective advocacy. 01.001 Peebles Tony 6/08/2009 11:04 Theme 01 The "Diagnostic Table" is too positive for existing devices - it seems to imply there are very few needs and that measurements are accurate. This is generally not the case on existing devices. I understand the need to provide contrast with the future. Howevr, I think the readiness box needs to be ALL yellow. However, I agree that the "Major Gaps" are in ITER and follow-up DEMO. 02.002 Peebles Tony 6/08/2009 11:05 Theme 02 The "Diagnostic Table" is too positive for existing devices - it seems to imply there are very few needs and that measurements are accurate. This is generally not the case on existing devices. I understand the need to provide contrast with the future. However, I think the readiness box needs to be ALL yellow. However, I agree that the "Major Gaps" are in ITER and follow-up DEMO. 01.002 Buttery Richard 6/08/2009 11:05 Theme 01 Consideration should be given to narrow proposed priority topics for US from "can do" to "should do" 01.003 Taylor Tony 6/08/2009 11:06 Theme 01 The Theme presentations were organized around the Panels. There are a number of issues that were presented as HIGH PRIORITY or HIGH IMPACT from the panesl that are missing from the thrusts. The question is are these missing from the thrusts as a result of priority decisions, or, as a result of unintended omission? There was significant discussion on the panels. How much discussion has there been on the themes? In particular in Theme 1, there was a panel on confinement issues and an panel on scenarios and heating and current drive. I understand that thrust 4 was to cover the high priority items from these two panels. The thrust seems NOT to include issues on confinement. 02.003 Buttery Richard 6/08/2009 11:07 Theme 02 Given US consensus that an extra facility(s) is needed before DEMO can be built, the priority of this week should be to agree that the US should proceed with this, and start to scope out the optimum set of missions for this facility. 04.001 Buttery Richard 6/08/2009 11:07 Theme 04 Given US consensus that an extra facility(s) is needed before DEMO can be built, the priority of this week should be to agree that the US should proceed with this, and start to scope out the optimum set of missions for this facility. 03.001 Buttery Richard 6/08/2009 11:07 Theme 03 Given US consensus that an extra facility(s) is needed before DEMO can be built, the priority of this week should be to agree that the US should proceed with this, and start to scope out the optimum set of missions for this facility. 02.004 Morley Neil 6/08/2009 11:10 Theme 02 A quick note in response to Ron Stambaugh's comment about linkages to theme 4, here are some ideas we have identified you may wish to consider. 1. Does the presence of tritium breeding blanket systems with significant ferromagnetic material, and 70 cm depth of moving, highly conducting liquid metal with it own error field generation affect plasma control by impacting placement of coils and sensors and field penetration times? 2. Do the design of plasma diagnostics systems for nuclear environment need accurate neutron transport simulation capabilities? 3. The need to meet tritium self sufficiency requirements for a system depend on many plasma issues like tritium burn fraction, recycling behavior, fueling efficiency, and placement and materials in plasma fueling/heating/control. Are we in danger of developing plasma operation modes and plasma control schemes that invalidate tritium self-sufficiency and power extraction functions including needed reliability and maintainabi 03.002 Buttery Richard 6/08/2009 11:12 Theme 03 Given US consensus that an extra facility(s) is needed before DEMO can be built, the priority of this week should be to agree that the US should proceed with this, and start to scope out the optimum set of missions for this facility. 02.005 Taylor Tony 6/08/2009 11:19 Theme 02 TOPIC Inclusion of key issues from "Panels" in the thrust. There are a number of items in the theme presentations that are presented as important, but do not show up in the thrusts (which have been presented as combining key issues from severl panels) Key question: Are the omissions a result of priority choice or a consequence of unintended omission in the combination. Specific question: Theme II presentation highlighted a need for electron heating from both RF and EC. In thrust 4, the need for developing EC and strong need for electron heating at the relevant colisonality and beta is totally missing. I think this is an oversight. 02.006 Berk Herb 6/08/2009 11:19 Theme 02 Amanda, What I was trying to get across with my question was that I felt that your presentation was not really addressing the issues of working for a Demo, but instead a presentation that would work well for the TTF transport meeting that focuses on our continued need to refine and expand our knowledge of the dynamics of plasma transport. Of course this issue is an essential for achieving Demo, but this issue is not new thrust of our program. Considering on how to go about achieving Demo is new and a concise summary of what we need to do as a program to achieve the knowledge is an issue that would be new. As I suggested I think it would be good to state with each of the issues what questions could be answered with existing experiments, what needs to be answered with ITER and what type of experiments we could build to answer the essential questions we need to know for building a Demo. 02.007 Berk 6/08/2009 11:20 Theme 02 Amanda, What I was trying to get across with my question was that I felt that your presentation was not really addressing the issues of working for a Demo, but instead a presentation that would work well for the TTF transport meeting that focuses on our continued need to refine and expand our knowledge of the dynamics of plasma transport. Of course this issue is an essential for achieving Demo, but this issue is not new thrust of our program. Considering on how to go about achieving Demo is new and a concise summary of what we need to do as a program to achieve the knowledge is an issue that would be new. As I suggested I think it would be good to state with each of the issues what questions could be answered with existing experiments, what needs to be answered with ITER and what type of experiments we could build to answer the essential questions we need to know for building a Demo. 03.003 wong Clement 6/08/2009 11:28 Theme 03 Based on Mike's presentation this morning: It would be appropriate to strengthen the identification on the unknowns on PFC surface material evolution and behavior from the DT products, namely alphas and neutrons. We know potential damages from alphas, like the W-blisters and W-fuzz, but this may be the tip of the iceberg. We have to get ourselves and the community to pay attention to these potential surface material damage contributors. We have to organize our modeling and experimental efforts accordingly. 03.004 Goldston Rob 6/08/2009 11:32 Theme 03 The integrated testing thrust is also parented by Theme 2. The issue of compatibility with the core plasma needs emphasis. In terms of additional pillars maybe the main one is the solution of off-normal events from Thrust 2. It should also be emphasized that the integrated testing needs to be done with long pulses, hot walls, and high power. 03.005 Goldston Rob 6/08/2009 11:32 Theme 03 The temperature limits for Li calculated in terms of evaporation rate does not take into account the probability that the evaporated Li gets into the plasma, and the impact on the plasma of the Li that does enter the plasma. Results from FTU and NSTX (and elsewhere) suggest that 400C may be too low a limit to set for liquid lithium. 03.006 Goldston Rob 6/08/2009 11:39 Theme 03 This was a very nice, high-level, understandable talk. Impressive job integrating this story together into an understandable overall picture. - Rob 03.007 Taylor Tony 6/08/2009 11:40 Theme 03 Topic Transient heat flux (ELMs) The last figure shows a diagram of the program progressing from present devices to demo. It was made clear during the presentation that the impulisive heat flux (from ELMs) is a much more serious problem than the steady state heat and particle flux. It was further stated that the "ITER solution" is not likely credible for DEMO. It is my opinion that if these statements correctly represent the tehnical status, then elimination or reduction of ELMs should be the major element of a thrust in this theme -- a new thrust or the key element in thrust 10 or thrust 11. 03.008 Wong Clement 6/08/2009 11:45 Theme 03 Mike emphasized the issue of quantifying the FW heat flux for ITER. ITER is now designing the FW blanket/shield at heat flux of 1-5 MW/m2, which is very different from the 0.5 MW/m2 that conceptual reactor designers have been using. Presently, the 5 MW/m2 for ITER at certain locations is from the parallel heat flux. We do have to understand much better on the contribution of blobs and parallel heat flux, which may not have been emphasized in our thrusts. The first wall heat removal for DEMO is very different from the divertor. Presently, we are optimizing our first wall design to ~0.5 MW/m2 with helium coolant and we are having problems already in balancing the temperature limit of <550 C for RAFS steel versus acceptable pumping power for the helium coolant. We will definitely degrade the reactor performance if a large section of the first wall will need to be designed for 1-5 MW/m2. The leads to the necessary emphasis of research needs in these areas in our thrust descriptions. 04.002 Goldston Rob 6/08/2009 11:54 Theme 04 As I understand the situation, a plasma which disrupts even once is incompatible with existing designs for breeding net tritium. The go / no go linkage to this issue needs much more emphasis in this discussion. Disruption elimination needs to be demonstrated in long-pulse high-duty-factor experiments to allow even CTF-level tests of blankets. 03.009 Peng Martin 6/08/2009 11:59 Theme 03 The theme description makes references to the need to carry out research in PMI in a full fusion nuclear environment, but says that one must first find integrated solutions in non-nuclear environment before testing the solutions in a full nuclear environment. This logic contains the weakness of a substantial likelihood that the non-nuclear solutions fails to function in a full nuclear environment. This logic is further not consistent with the statement in the Greenwald panel report regarding PMI, which included the condition of "under very high neutron fluence" in defining the R&D needs. The creation of a full fusion nuclear environment to enable the required full range of PMI research, including the partial non-nuclear solutions research, therefore should be a key element in the research thrusts included in Theme 3. 04.003 Goldston Rob 6/08/2009 12:05 Theme 04 I would be cautious about using Tore Supra as an example of disruption-free operation. In their recent attempt to make a long series of long-pulse discharges, they had to dial back the length of the long-pulse discharges because every one disrupted. They believe that this was because of overheating of C co-deposited layers, which may not exist in future devices, but as it stands, the T-S results do not demonstrate disruption-free operation. Quite the opposite. 01.004 Peng Martin 6/08/2009 13:14 Theme 01 Theme 4 presentation and write-up contain R&D goals, the success of which will depend very much on the success of disruption avoidance and mitigation research in Themes 1 and 2. This points to the need to raise the importance of, or at least clearly include, disruption avoidance and mitigation in some research thursts from Themes 1 and 2. 02.008 Peng Martin 6/08/2009 13:15 Theme 02 Theme 4 presentation and write-up contain R&D goals, the success of which will depend very much on the success of disruption avoidance and mitigation research in Themes 1 and 2. This points to the need to raise the importance of, or at least clearly include, disruption avoidance and mitigation in some research thursts from Themes 1 and 2. This is a duplicate chit to Theme 1. 05.001 intrator tom 6/08/2009 13:32 Theme 05 might be useful to add an FRC accomplishment as -- creation of high density (5e22m-3), high pressure (20-30 bar) frc plasmas 05.002 intrator tom 6/08/2009 13:58 Theme 05 just to amplify on the question on (paraphrased) "why bother spreading out our resources on tangents to mainstream approaches?" Especially since themes 1-4 call out physics and engineering, vs theme 5 that calls out configurations. response could include ... we need some game changers, and there is a long list (eg disruptions, magnet cost, simple geometry, lithium, no center stack, engineering simplicity and modularity that follows from simply connected, eases super conducting magnet implementation… ) 05.003 Milroy Richard 6/08/2009 14:00 Theme 05 On page 3 there is a summary of the FRC with four bullets. It should contain a bullet acknowleging the field-reversed-theta-pinch. I suggest that a bullet should be added at the top which reads something like: "High density, high temperature FRCs have been routinely formed in field reversed theta-pinch devices, over may years. 05.004 Jarboe Tom 6/08/2009 14:06 Theme 05 First spheromak bullet should not have"inductive" in it. 05.005 Sovinec Carl 6/08/2009 14:37 Theme 05 In 5.1.2 (Highlights), the first bullet for the spheromak needs clarification. The parameters that are listed have not been achieved simultaneously. What is meant by "steady-state inductive helicity injection?" Also, the 500 eV temperature is not a steady-state result. 05.006 Hsu Scott 6/08/2009 14:41 Theme 05 The language is too technical. At this point, the theme summary will be useful only for ourselves and OFES program managers. Thus, the impact will be very limited. If we aspire to achieve the impact of the BES documents (i.e., growth in the program and excitement beyond our own community), then our documents must be easily understood by any college educated person. Another comment is that the BES process did a good job of identifying engineering outcomes/deliverables (i.e., closed fuel cycle for advanced nuclear fission energy) and then working backwards to the discovery science that is needed. I do not think these connections are necessarily clear in our case. In fact, discovery science has not been emphasized enough. Ideally, the documents need to be rewritten, perhaps with the help of a professional science writer. We will be squandering the opportunity to achieve maximum impact if we take shortcuts now. These comments apply to all 5 themes. 02.009 Chan Vincent 6/08/2009 15:10 Theme 02 If this has not happened already, it would be very useful for this theme (and other themes as well) to do a risk assessment of the proposed tasks. What would be the consequence of not doing a task or skipping an incremental step in order to speed up the timescale to DEMO? Since DOE has specifically asked the ReNeW team not to prioritize the tasks, the risk assessment will be very helpful for DOE to make program decisions. 05.007 Hazeltine Richard 6/08/2009 16:01 Theme 05 The cube is a good idea, but I find the present form misleading. Putting all the non-stellarator dots on the floor ignores the wealth of experiments and extensive theory on symmetry breaking in tokamaks. A more accurate and instructive picture would show the tokamak dot far below the stellarator, but not quite on the floor. 05.008 Woodruff Simon 6/08/2009 16:33 Theme 05 Three comments: 1. We should strke a balance between presentation of theme 5 as 'game changing' and 'relevant'. While concept specific innovations may well solve outstanding issues in mainline concepts, the opportunity presented by renew is to make connections to the broad program. There are only few of us trying to make fusion work, and it will likely take all of us. 2. Context for renew was set by the FESAC TAP: some very insightful figures ilustrating eg iter era parameter goals for each concept can be found in the final report. 3. If we want to communicate with a wider audience, consider handing the draft we (scientists) produce to a non-scientist to edit. 03.010 nygren richard 6/08/2009 16:53 Theme 03 A. Add figure(s) in Chapter 3. There were several excellent figures in presentation. 03.011 nygren richard 6/08/2009 16:54 Theme 03 Specify in "links" which items share common concerns AND differentiate where the impetus or responsibility also of interest in this thrust is assumed to be covered preferentially in another thrust. 03.012 nygren richard 6/08/2009 16:55 Theme 03 Make clear where concern about neutron effects is liked to the need for integrated testing in an nuclear test stand or D/T facility. 05.009 Milroy Richard 6/08/2009 20:54 Theme 05 On page 39 there is an equation with n(Te+Ti) ~ Be2 /2… Here the 2 should be a superscript. On the same page there is a "1019", where the 19 should be superscript 05.010 Milroy Richard 6/08/2009 20:58 Theme 05 The first paragraph 5.2.4.3 on page 40, was changed from the last draft, and the last two sentences seem to have lost their meaning. I would suggest the following paragraph. (NOTE: I changed the word "colliding" to "merging".) FRC flux sustainment requires overcoming the ohmic losses associated with maintaining the diamagnetic toroidal currents. However, the cross-field resistivity η_perp is found to be anomalously high and needs to be decreased for sustainment at low power. Present experimental facilities are capable of studying some aspects of RMF and merging spheromaks, although the latter cannot presently study steady-state current drive. Unless the experiment used to study large-s is capable of current-drive and sustainment, a new experiment is needed to extend present work and fill this gap. 02.010 Temkin Richard 6/08/2009 22:10 Theme 02 I would not use the word “actuator” to describe the plasma control systems such as heating, fueling, etc. The word “actuator” is ordinarily used to describe “a mechanical device for moving or controlling a mechanism or system.” Using the word “actuator” will really confuse people, especially non-fusion people. I would replace “actuator” with the specific device or devices needed such as “heating and fueling systems.” I would make the replacement everywhere in the Theme write-up. 04.004 Neilson Hutch 6/08/2009 23:25 Theme 04 Under what conditions is a neutron irradiation facility like IFMIF or a LANSCE upgrade needed? It was not as clear as it should be, given its importance. 04.005 Cohen Sam 6/09/2009 11:31 Theme 04 Comment on the time line relating RAMI and fuel cycle: The efforts to bring tokamak-based fusion power to reality start today, with the ITER era. A 30-year-duration DEMO reactor phase would follow, to demonstrate reliable and safe operation at reactor-level power. The first multi-GW tokamak reactor will be ready for design, licensing, and construction in 2060. This power plant would start operations in 2070. The tritium fuel for one year’s operation would deplete all that is available in nuclear stockpiles, but since this reactor is expected to breed its own fuel, it would be self supporting. However, whence the T fuel for the additional 999 multi-GW fusion reactors proposed to provided a goodly fraction of the global electricity needs? If the first tokamak reactor bred only 10% more T than it needed, it would take 10 years to provide fuel for one more reactor. By this doubling process, it would take 100 years to fuel 1000 reactors. 2170? A late date. 05.011 Jarboe Tom 6/09/2009 13:39 Theme 05 Table at the end. #5 CT should have a 3. CTs make large contributions in efficient steady state current drive and CT injection fueling. On top of page 44. replace "The spheromaks ohmicly heated to e,peak > 20% before a strong pressure-driven instability occurred." with "The spheromaks ohmicly heated to e,peak > 20% before a pressure-driven interchange occurred, demonstrating ohmic heating to the beta limit. 02.011 Jarboe tom 6/09/2009 14:16 Theme 02 In a high-Q reactor with a high level of bootstrap current fraction, the external input power would be significantly reduced. As a result, precision fueling may be the only way to control the internal density (and hence the pressure) profile. This is clearly recognized and noted in the Greenwald panel report. Recognition of the need for advanced fueling systems is lacking at the higher levels of thrust 5 and it should be clearly noted in first thrust page, because unlike the other auxiliary systems (RF, RWM coils), there is no program at present in the area of advanced fueling. 05.012 Cohen Sam 6/10/2009 10:46 Theme 05 Place more emphasis on advanced fuels in CTs, to overcome some of the major materials issues caused by D-T burning and tritium breeding.