Status of the ITER Design Review: Needs from the Physics Community

1. Status of the ITER Design Review:Needs from the Physics Community D Campbell ITER International Organization Acknowledgements: G Janeschitz, P Thomas and many colleagues in the ITER IO and international fusion community who are contributing to the Design Review ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

2. Synopsis • Aim of the ITER Design Review • scope • implementation • status • Design Requirements and Physics Objectives WG • High priority issues • Relation to other Working Group activities • Summary ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

3. ITER Design Review The Design Review Process has the following essential objectives with respect to the 2001 design report: • Identify all systems that are not designed yet or are still in the conceptual stage. • Starting from the 2001 final design report, identify all systems that have integration or technical issues which need to or should be resolved before a procurement specification can be assembled. Identify the issues and a path forward for resolution. • Identify areas, concepts and technical designs where recent R&D results indicate a possible performance problem or an unacceptably high manufacturing cost. Identify issues and path for resolution • Identify areas, concepts and technical designs in which recent R&D results would benefit the design technically, schedule or cost-wise. • Prioritize open issues with respect to scope, schedule and cost impact and identify and implement solutions in the order of priority. In order to do this the integration group will provide a risk assessment document that will guide the risk assessment in terms of scope, schedule and cost, and assign a priority number. ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

4. Goals of the Design Review • First goal for 2007 is to create a new Baseline Design 2007 which: • Confirms or redefines the physics basis and requirements for the project • Is the basis for the procurement of the long lead items (Vacuum Vessel, Magnets, Buildings), • provides input for the Preliminary Safety Report • For components and systems which are procured at a later date or for issues with lower priority work will continue into the year 2008 • Second goal is to base the ITER design decisions also in detail on a broad basis by involving the worldwide fusion community (physics and engineering) • Fusion community and the Parties can take ownership of the project • Third goal is to broaden the knowledge basis into the parties which is essential for a successful procurement of the ITER components in kind • A significant part of technical coaching of industry and of the QA will rest with the Domestic Agencies (DAs) ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

5. Design Review is performed by 8 Working Groups~150 members WG-1 - Design Reqs. & Physics Objectives. Chair: P.Thomas; IO D.Campbell WG-2 - Safety and Licensing Chair: J-P Perves; IO J-P.Girard WG-3 - Site and Buildings Chair: C.Strawbridge; IO J.Sovka WG-4 - Magnets Chair: M.Huguet; IO N.Mitchell WG-5 - Vacuum Vessel Chair: Songtao Wu; IO K.Ioki WG-6 - Heating and Current Drive Chair: J.Jacquinot; IO A.Tanga WG-7 - Tritium Plant Chair: D.Murdoch; IO M.Glugla WG-8 - In-Vessel Components Chair: Igor Mazul; IO M.Pick/C.Lowry The membership consists of the leading experts of the fusion community in each party The groups have written manifestos explaining the scope of their work In order to solve issues, work packages have been agreed with the Parties based on the work plans established by the design review working groups ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

6. Role of Working Groups • The responsibility of the Working Groups is defined as: • To review the current design and impact of design changes since 2001. • To review existing and identify new issues to complete the procurement specifications. • To take corrective actions to resolve these issues, if possible within the resources of the working group. • For larger issues to propose the plan for corrective actions or inclusion in the risk portfolio. • To estimate impacts on cost, schedule, performance and estimate the amount of resources to complete the plan. • To regularly inform the ITER IO and PTs of progress • In some areas there is significant overlap between the activities of the WGs and co-ordination is maintained through several mechanisms (eg Design Review Interface Meetings). ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

7. ITER Issues • ~ 200 issues existed for several years but were, for various reasons, not solved, or rejected • Another ~ 250 were added by the Parties last autumn when the design review process started • Thus ~ 450 issue cards existed when the Design Review working groups were formed in December of 2006 and started work • At the moment there are 411 ongoing issues • 186 issues require consideration by more than one group ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

8. Condensation of High Priority Issues The high priority issues (including some the medium and low priority issues) have been condensed into fewer issues covering the same range of problems The total number is 65 compared to 411original issues ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

9. WG1 Activity:Design Requirements and Physics Objectives Mandate: • Determine if the Design Requirements for ITER systems and subsystems are correct, adequate and complete • Where this is not the case, develop or propose solutions Working Procedure: • As a result of 2 extended workshops, WG1 has condensed the most critical issues within its remit to 12 high priority issues • In addition, 2 special sub-groups have been added to the WG1 scope: • Wall Conditioning • Measurements ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

10. High Priority Issues I • ITER Project Development Plan • Fusion performance sensitivity studies • Identify TF ripple requirements for the attainment of physics objectives • Review PID requirements for disruptions, VDEs and runaways • Choice of plasma facing components • Requirements for tritium breeding blanket in exploitation phase II ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

11. High Priority Issues II • Development of start-up scenarios • Assure required space reserved for RWM and ELM control windings • Impact of increased gas loads due to ELM pacing and disruption mitigation on pumping systems (impacts building size) • Ensure reliability of ITER systems - engineering practices, configuration control, and QA support to procurement • Assessment of the maintenance requirements inside the cryostat • Auxiliary heating and current drive ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

12. 1. An ITER Development Plan • Project Development Plan required by Design Review process to guide analysis of design requirements • Plan should consist of key elements determining structure of construction and operation programmes, eg: • Experimental programme plan for operational campaigns • Schedule of installation/ commissioning plans of equipment required to meet objectives  decision points for upgrades • Key licensing milestones • Commissioning and start-up plan for ITER • Plan for provision of services required for upgrades • Further development of “Construction, Commissioning and Operation Plan” required • To be led by ITER Team • contributions needed from each of Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

13. 2. Fusion performance sensitivity studies • Requirement is analyze sensitivity of ITER performance predictions to small variations in key parameters (Ip, B, ) • Design scenarios to be reviewed as a minimum • Several approaches to analysis should be pursued: • Spreadsheet scalings from baseline scenario • Analysis using calibrated 1-D transport models • Analysis using 1-D codes with 1st principles transport models • Operating space diagrams (eg POPCON) • Projections of advanced operating modes from current experiments • Analysis of more detailed implications of scenario variations • Strong interaction with Magnets WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

14. 3.TF ripple requirements • Assessment of acceptable level of TF ripple to ensure performance objectives met • Aspects which need to be reviewed include: • Present optimization of ferritic inserts for full field operation • Implications of enhanced ripple at half-field on ITER operational planning • Influence of field ripple due to TBMs • Several physics issues need to be considered: • TF ripple induced energetic particle losses • Impact of ripple on H-mode access, thermal confinement and plasma rotation • Interaction between redistribution of energetic particles due to mhd and enhanced losses due to ripple • Some interaction with Vessel & Interfaces WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

15. 4.Requirements for disruptions, VDEs and runaways • Disruptions and VDEs generate high thermal loads, large electromagnetic forces and potentially significant runaway electron beams • Specification of loads associated with disruptions/ VDEs should be reassessed in light of recent data/ analysis: • Impacts on mechanical design of tokamak structure • Influences PFC lifetime - could impact on choice of PFCs • Design implications of disruption mitigation system(s) need to be assessed • Particular attention needs to be given to mitigation of runaway electrons • Some interaction with In-vessel Components WG • Involvement of ITER plus several Parties required ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

16. 5. Choice of PFCs I • Present choice of PFCs should be reviewed in the light of ITER R&D results, progress in tokamak R&D and specific studies made to address: T-retention, disruption/ ELM effects etc • Issues with present design: • Limited experience with (uncoated) W in tokamaks • Tritium retention - both in C and in metals • Lack of demonstrated T-removal technique for ITER • Adequacy of existing bakeout capability to condition divertor tiles and remove tritium • Effect of impulsive heat loads (disruptions/ ELMs) • Need for protection from runaways - possibility of protection limiters? • Uncertainties in mixed material properties • Influx of W due to ICRF sheaths • A later exchange appears to imply a 7 year lead time and a substantial shut down time - may also imply design changes to facilitate exchange of first wall ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

17. 5. Choice of PFCs II • Issue cards propose several variations of initial PFC mix • Operational implications for scientific programme to be evaluated • Strategy for subsequent exchange needs to be developed - likely possible only at 10-year intervals • DR&PO-WG contributions: • Evaluation of programmatic implications (ITER, DEMO) • Assessment of plasma performance with proposed PFC mix • Project development plan for qualifying tritium inventory, need for cleaning intervals, acceptable down-time etc • Review of bake-out requirements • Developing start-up scenario with heat load definitions • Evaluation of reliability of ELM control and disruption avoidance/ mitigation • Strong interaction with In-vessel Components WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

18. In-Vessel Components WG • WG8 analysis is at a more preliminary stage, due to its more recent establishment - it has identified following issues for its workprogramme: • Update loading conditions for FW – specifies requirements • Report on design problems for blanket system and ideas for resolution • Assessment of improved component alignment to mitigate problems • Poloidal limiter design concept • Requirements for Hot Cell, waste, RH – depends on recommendation of WG 1 • Modification of RH – first ideas and design concepts • Concept of radiative wall segments to improve exchangeability ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

19. 6. Requirement for tritium breeding blanket in phase II • ITER objectives require that option for breeding of tritium should be maintained via replacement of outboard shielding modules with T-breeding blanket modules during last 10 years of operation • DR&PO-WG should provide estimate of need for tritium breeding in ITER: • Based on ITER Project Development Plan • Reasonably conservative assumptions about external tritium supplies • Assessment of other tritium needs of programme, eg start-up of subsequent devices • Design implications of such a requirement would need to be handled by In-vessel Components WG - also possible interactions with Vessel & Interfaces WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

20. 7. Development of start-up scenarios • Plasma initiation and current rise phase needs to be optimized to ensure that required range of design scenarios can be established and that ITER can reach its primary goals • Physics issues: • Access to a range of operating scenarios • Compatibility of PFCs with required ramp-up scenarios • Required analysis: • Reviewing/ Agreeing range of ITER operating scenarios • Plasma transport simulations - resistive voltage drop/ flux penetration • Simulation of PF control system, power supplies, plasma equilibrium • Assessment of plasma vertical stability during start-up • Strong interaction with Magnets WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

21. 8. Assure space for RWM and ELM control windings • Additional coil set(s) may be required in ITER to correct error fields, suppress ELMs and stabilize resistive wall modes • Physics issues: • Effectiveness of proposed coil sets (including baseline set) for each purpose • Operational necessity and flexibility afforded by inclusion of control capability • Required analysis: • Analysis of performance of each coil set proposed for EFCC, ELM control and RWM control • Evaluation of machine space and coil performance requirements • Evaluation of implications for power supplies • Identification of any high priority diagnostic consequences • Interaction with Magnets, Vessel and In-Vessel Components WGs • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

22. 9. Impact of gas loads due to ELM pacing/ disruption mitigation on building design • Requirements for ELM pacing via pellet injection and disruption mitigation via massive gas injection might lead to a significant increase of pumping requirements to ensure operational reliability/ flexibility, with potential implications for tokamak building • Required analysis: • Estimate of gas loads implied by ELM pacing and disruption mitigation • Evaluation of implications for pumping and for operational reliability/ flexibility • Analysis of gas requirements for disruption mitigation/ runaway suppression (see also Issue 4) • Possible interactions with Tritium Plant and In-vessel Components WGs • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

23. 10. Ensuring reliability of ITER QA systems • Provision of management system for internal control of the design process is necessary • Actions required: • Use of recognized standard for internal management system, eg ISO 9001 (2000) • Establish system for classification of key requirements such as RH, tritium contamination/ inventory, safety critical equipment …eg identifcation of class 1 components should trigger defined approach to design, manufacture, monitoring and protection systems etc • Establish a process for execution, review and sign-off on design • Define design review procedures at several stages of design • Implement these procedures for existing designs • Define and implement clear heirarchy of project documentation • Reliability and availability assessment of major systems also required, perhaps on longer timescale • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

24. 11. Assessment of maintenance requirements inside cryostat • Cryostat hosts series of components, mostly magnet-related, which might require maintenance • Required analysis: • Assess requirements for in-cryostat component accessibility - identify measures to prevent failure, redundancy measures etc • Assemble and evaluate documentation on radiation dosage levels and requirements for cryostat entry during operational phase - update if necessary to latest design status (eg shielding blankets) • Verify that components which might require intervention can be accessed and their design compatible with intervention/ access • Some interactions with Magnets WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

25. 12. Auxiliary Heating and Current Drive I • A series of issues related to design and performance of H&CD systems, exploitation in ITER scenarios and strategy for upgrades has been identified with potential implications for long-lead items • Issues identified: • Heat load capability of the ITER core - requires analysis of current design to assess capability for meeting performance goals and identification of all elements which might limit extension of ITER performance • Neutral beam energy, power and momentum - includes assessment of energy and current for full performance, strategy for ITER H-phase, controllability of beam power, diagnostic requirements: • Reduced energy/ higher current in 2 planned beamlines • Low energy injector on 3rd beamline for higher momentum input • Capability for variable beam voltage for initial operation • Real-time variation of the NBI power - power modulation (?) • NNBI performance requirements for MSE diagnostics ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

26. 12. Auxiliary Heating and Current Drive II • Issues identified: • Modifications to ECRH Equatorial Launcher for improved flexibility • Allocation of a specific port for Lower Hybrid Launcher • Strong interaction with Heating and Current Drive WG • Involvement of ITER plus several Parties ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

27. Heating and Current Drive Working Group • Overall H&CD Issues: • Potential change of start up set for H&CD  WG1 • Four upgrade Scenarios in PID difficult to plan for - recommend priority to only two • Neutral Beams: • Change of Beams to 500 keV energy – consequences on ports, VV, power • Beam ducts redesign including RH  WG5 • NBI readiness assessment – implications on start up set  WG1 • RF Systems: • Hot Cell Testbed for all 3 RF heating systems • Insufficient RF Installation and Commissioning Time (ICRF and ECRH) • ICRF Antenna Concept Choice (on schedule – selection underway) • ICRF Screen material (Low Z – Beryllium – difficulty with W) • ICRH discharge cleaning (difficulty with Glow), possibly also with LH • ECRH midplane port – current drive in both directions • ECRH Possible upgrade to ~2MW per gyrotron – consequences for waveguides • LH voluntary effort from parties supported by IO ? ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

28. 13. Wall conditioning • A specific sub-group on Wall Conditioning has been established to review ITER requirements and capabilities • The sub-group has identified the main elements which it should address in its work: • Ab-initio conditioning of vessel/ in-vessel components • Campaign and inter-shot conditioning • Disruption recovery • Dust removal • Difficulties with GDC in ITER environment • Need for RF systems to contribute • Work programme has been established and contributions from the Parties solicited ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

29. 14. Measurements Proposal from the US Party Leader – mandate of separate WG: • to review the choice of selected diagnostics, port allocation, and prioritization (space allocation) in the light of ITER measurement requirements; • to assess measurement capability of integrated system in relation to ITER measurement requirements (assuming reasonable success with design and any needed supporting R&D); • to consider changes that may be necessary due to possible changes in requirements and/or the machine design coming from the wider ITER design review; • to handle any diagnostic related issues that have been raised through the design review process that are not currently owned or being dealt with by one of the existing working groups. Outcome is an additional sub-group of WG1 – to report July • to meet once, for one week, with 1 member per Party • PT Leaders should appoint Party representatives • ITER IO to provide coordinator/secretary ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007

30. Summary The Design Review activity is addressing a series of key physics and engineering issues related to the finalization of the ITER Design • The timescale for the Design Review is set by the need to prepare new ITER baseline documentation by the end of 2007 • Many issues addressed in the Design Review were identified through the ITPA activity implemented in 2006. • The fusion community contributions to the analysis are largely being organized through the Participant Teams. • There is considerable scope for physics input to the process - it is clear that plasma modelling will play an important role in the analysis in many areas. • The physics community can have a major impact on the process by ensuring that state-of-the-art experimental, theoretical and modelling information is made available. ITPA CDB&M and TP Topical Group Meetings, Lausanne, 7-10 May 2007