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F. Le Guern Dust&Tritium PWI AM Frascati 27-29 Oct 2008 DUST AND TRITIUM MANAGEMENT.

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Presentation on theme: "F. Le Guern Dust&Tritium PWI AM Frascati 27-29 Oct 2008 DUST AND TRITIUM MANAGEMENT."— Presentation transcript:

1 F. Le Guern Dust&Tritium PWI AM Frascati Oct 2008 DUST AND TRITIUM MANAGEMENT

2 F. Le Guern Dust&Tritium PWI AM Frascati Oct 2008 OUTLINE INTRODUCTION SAFETY AND OPERATION CONSTRAINTS ON ITER DUST INVENTORY TRITIUM INVENTORY RECOMMENDATIONS FOR 2009 PROGRAMMES CONCLUSION DUST AND TRITIUM MANAGEMENT

3 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Combined request from F4E&EFDA managements:Combined request from F4E&EFDA managements: Establish the status of the R&D on: Establish the status of the R&D on: in-vessel dust and tritium inventory measurement techniquesin-vessel dust and tritium inventory measurement techniques in-vessel detritiation and dust removal techniquesin-vessel detritiation and dust removal techniques Propose objectives for an R&D program Propose objectives for an R&D program Introduction (1/2)

4 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Decision to gather European experts including PWI TFLs, JET TF_FT and JET TF_D TFLs Decision to gather European experts including PWI TFLs, JET TF_FT and JET TF_D TFLs MembersP. Coad G. Counsell J. Furlan C. Grisolia F. Le Guern D. Maisonnier A. Murari V. Philipps S. Rosanvallon J. Roth E. Tsitrone UKAEA-Deputy Task Force Leader Fusion Technology-JET F4E CEA-Task Force Leader Fusion Technology-JET EFDA ENEA-Task Force Leader Diagnostics-JET FZJ-JET ILW Project Scientist CEA-Project Leader on Dust IPP- Task Force Leader Plasma Wall Interaction CEA-Deputy Task Force Leader Plasma Wall Interaction Introduction (2/2)

5 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Safety and operation constraints on ITER:Safety and operation constraints on ITER: Safety limits defined in the RPRS report*: Safety limits defined in the RPRS report*: Kg of dust in the VV g of tritium in the VV Accident Analysis report**: risk of explosion of dust deposited on hot surfaces: Accident Analysis report**: risk of explosion of dust deposited on hot surfaces: - limits defined for hot dusts(1000 kg: cold dusts): 6 Kg of W 6 Kg of Be 6 Kg of C ITER procedure: removal of dust every 16 months by vacuum cleaning (not yet in ITER baseline) and RH vacuum cleaning every 3-4 years during divertor cassettes replacement ITER procedure: removal of dust every 16 months by vacuum cleaning (not yet in ITER baseline) and RH vacuum cleaning every 3-4 years during divertor cassettes replacement ITER deadlines: it is a urgent matter ITER deadlines: it is a urgent matter *RPrS: Note 7 of Files for request of creation authorization : Preliminary Safety Report. C.Gordon, 25/01/08 **Accident Analysis Report : ITER D 2DPVGT v1.0, N.Taylor, 26/05/08

6 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Dust inventory:Dust inventory: Current ITER assumptions: Current ITER assumptions: - Steady state + ELMs (<0.5 MJ/m 2 ) 75 g/disharge - Disruption: 5Kg/disruption (1 disruption every 66 discharges) more than 5000 discharges before reaching the cold dust safety limit more than 5000 discharges before reaching the cold dust safety limit Group comments: Group comments: -It seems difficult to guarantee ELMs energy <0.5 MJ/m 2 (see Russian experiments*) (see Russian experiments*) -1 disruption every 66 discharges looks optimistic -Issue of hot dust not sufficiently addressed *See Experimental study of PFCs erosion under ITER-like transient loads at plasma gun facility QSPA, N. Klimov et al., Oral Presentation, PSI conference, Toledo, May 2008

7 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT General recommendations for dust (1/2):General recommendations for dust (1/2): It is necessary to define, test and assess method(s) to remove dust during maintenance phases. It is necessary to define, test and assess method(s) to remove dust during maintenance phases. Due to uncertainties (mainly on mitigation of ELMs), it is recommended to develop, test and assess methods to measure erosion in the VV. In this way it will be possible, based on estimates of the relationship between erosion and dust accumulation, to decide whether or not to proceed with dust removal before the foreseen maintenance. Due to uncertainties (mainly on mitigation of ELMs), it is recommended to develop, test and assess methods to measure erosion in the VV. In this way it will be possible, based on estimates of the relationship between erosion and dust accumulation, to decide whether or not to proceed with dust removal before the foreseen maintenance.

8 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT General recommendations for dust (2/2):General recommendations for dust (2/2): The group considered that measuring low quantities of dusts spread over large surfaces, at high temperature and in a nuclear fusion environment is very demanding and stressed the need 1) to carry out an exhaustive review of potential low quantity dust measurement techniques,2) to investigate possible cleaning techniques in order to guarantee that the divertor region(PFCs surface) is almost dust free during operation of the machine. The group considered that measuring low quantities of dusts spread over large surfaces, at high temperature and in a nuclear fusion environment is very demanding and stressed the need 1) to carry out an exhaustive review of potential low quantity dust measurement techniques,2) to investigate possible cleaning techniques in order to guarantee that the divertor region(PFCs surface) is almost dust free during operation of the machine. Furthermore, keeping in mind that the development of such a technique is very challenging, it is also recommended to proceed in parallel with the assessment of explosion mitigation methods (inert gas injection) and possible design enhancements to limit air ingress or to improve the sustainability of the VV to the transient peak pressure (mechanical design of the vessel itself) ( covered by F4E). Furthermore, keeping in mind that the development of such a technique is very challenging, it is also recommended to proceed in parallel with the assessment of explosion mitigation methods (inert gas injection) and possible design enhancements to limit air ingress or to improve the sustainability of the VV to the transient peak pressure (mechanical design of the vessel itself) ( covered by F4E).

9 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Tritium inventory:Tritium inventory: Estimations* based on: Estimations* based on: - Databases (wall fluxes, erosion/deposition rates, saturation level versus material(C, Be, W)) - Code calculations (D+T fluxes, transport codes) Safety tritium limit could be reached after a few hundred shots (mix: C, Be,W) Safety tritium limit could be reached after a few hundred shots (mix: C, Be,W) Group estimates that this approach is not conservative due to: Group estimates that this approach is not conservative due to: - potential non-mitigated ELMs - potential non-mitigated disruptions *Recent Analysis of Key Plasma Wall Interactions Issues for ITER, J. Roth et al, PSI 18 Toledo, May 2008

10 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT General recommendations for tritium:General recommendations for tritium: Studies on development of ITER scenarios in view of minimising tritium trapping (e.g DD sequence at the end of each DT pulse) Studies on development of ITER scenarios in view of minimising tritium trapping (e.g DD sequence at the end of each DT pulse) Define, test and assess method/s to detritiate between and during the foreseen maintenance phases. Define, test and assess method/s to detritiate between and during the foreseen maintenance phases. Develop methods to measure the fuel retention already in the non activated phase globally by gas balance and to analyse locally and time resolved the amount and distribution of retained fuel (tritium) in the VV during, in between shots or during nights/weekends. Develop methods to measure the fuel retention already in the non activated phase globally by gas balance and to analyse locally and time resolved the amount and distribution of retained fuel (tritium) in the VV during, in between shots or during nights/weekends.

11 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Recommendations for 2009 programmes:Recommendations for 2009 programmes: Selection of relevant techniques (Pro&Cons analysis) according to the following criteria: Selection of relevant techniques (Pro&Cons analysis) according to the following criteria: - Performances, level of assessment - Relevancy with respect to ITER constraints The goal in 2009 is to perform feasibility studies in order to assess the possibility to implement those relevant techniques on ITER The goal in 2009 is to perform feasibility studies in order to assess the possibility to implement those relevant techniques on ITER In case of positive outcome an R&D proposal based on a project oriented approach shall be provided In case of positive outcome an R&D proposal based on a project oriented approach shall be provided

12 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

13 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

14 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

15 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

16 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Conclusion (1/2):Conclusion (1/2): Significant uncertainties on the predictions for dust production and tritium trapping in ITER identified Significant uncertainties on the predictions for dust production and tritium trapping in ITER identified Potential techniques have been reviewed and the most relevant selected Potential techniques have been reviewed and the most relevant selected It is proposed to perform feasibility studies in In case of positive outcome a detailed project proposal shall be proposed. It is proposed to perform feasibility studies in In case of positive outcome a detailed project proposal shall be proposed.

17 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Conclusion (2/2):Conclusion (2/2): Proposal recommended by EFDA-STAC (Brussels- 25/09/2008) Proposal recommended by EFDA-STAC (Brussels- 25/09/2008) Programme proposal endorsed by EFDA steering committee (JET-06/10/2008) Programme proposal endorsed by EFDA steering committee (JET-06/10/2008) Call for proposal is being launched after sharing of tasks between F4E and EFDA. Call for proposal is being launched after sharing of tasks between F4E and EFDA.

18 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

19 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Dust accumulation areas

20 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT IVVS SCANNING HEAD Optical fiber P out

21 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT

22 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Deadlines: – Port plug mounted systems: Final design agreed among all stakeholders: end 2014 – Divertor cassette mounted systems Delivery to ITER: end 2016 – In-Vessel mounted systems Delivery to ITER: end 2014 – Adaptation or use of space on the IVVS system Final design agreed among all stakeholders: end 2016

23 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT ELM Disruption level, w > 2.2MJ/m 2 CFC fibers erosion as a function of surface energy density Erosion (H pitch -H PAN ), m

24 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Possible design Laser 5mm Divergence 60mmlens Beamexpansion=10 60mmlens f=15m Scanningmirror Vacuum Spherical mirror Divertor Target Edge mirror C,W, H light Laser beam from upper portplug or from midplane Detection from midplane or in line with laser Detection: lower inner wall, baffle and part of dome

25 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT DEM system for ITER

26 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT Galvanometric scan Fiber for laser input

27 F. Le Guern Dust&Tritium PWI AM Frascati Oct of ? slides DUST AND TRITIUM MANAGEMENT


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