f. le guern dust&tritium pwi am frascati 27-29 oct 2008 dust and tritium management

F. Le Guern Dust&Tritium PWI AM Frascati 27-29 Oct 2008

DUST AND TRITIUM DUST AND TRITIUM MANAGEMENTMANAGEMENT


OUTLINEOUTLINE

INTRODUCTION INTRODUCTION

SAFETY AND OPERATION CONSTRAINTS ON ITERSAFETY AND OPERATION CONSTRAINTS ON ITER DUST INVENTORYDUST INVENTORY

TRITIUM INVENTORYTRITIUM INVENTORY

RECOMMENDATIONS FOR 2009 PROGRAMMESRECOMMENDATIONS FOR 2009 PROGRAMMES

CONCLUSIONCONCLUSION

DUST AND TRITIUM MANAGEMENTDUST AND TRITIUM MANAGEMENT


of ? slides


• 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 in-vessel dust and tritium inventory measurement

techniquestechniques• in-vessel detritiation and dust removal techniques in-vessel detritiation and dust removal techniques

Propose objectives for an R&D program Propose objectives for an R&D program

Introduction (1/2)


of ? slides


Decision to gather European experts including PWI Decision to gather European experts including PWI TFLs, JET TF_FT and JET TF_D TFLsTFLs, JET TF_FT and JET TF_D TFLs

Members P. CoadG. CounsellJ. FurlanC. Grisolia F. Le GuernD. MaisonnierA. MurariV. PhilippsS. RosanvallonJ. RothE. Tsitrone

UKAEA-Deputy Task Force Leader Fusion Technology-JETF4EF4ECEA-Task Force Leader Fusion Technology-JET EFDA EFDAENEA-Task Force Leader Diagnostics-JETFZJ-JET ILW Project ScientistCEA-Project Leader on DustIPP- Task Force Leader Plasma Wall InteractionCEA-Deputy Task Force Leader Plasma Wall Interaction

Introduction (2/2)


of ? slides

DUST AND TRITIUM MANAGEMENTDUST 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*: - 1000 Kg of dust in the VV- 1000 Kg of dust in the VV- 880 g of tritium in the VV- 880 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”):- limits defined for “hot dusts’’(1000 kg: “cold dusts”):

6 Kg of W6 Kg of W6 Kg of Be6 Kg of Be6 Kg of C6 Kg of C

ITER procedure: removal of dust every 16 months by vacuum cleaning (not yet in ITER 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 replacementbaseline) 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


of ? slides


• Dust inventory:Dust inventory:

Current ITER assumptions: Current ITER assumptions: - Steady state + ELMs (<0.5 MJ/m- Steady state + ELMs (<0.5 MJ/m22))75 g/disharge75 g/disharge- Disruption: 5Kg/disruption (1 disruption every 66 - Disruption: 5Kg/disruption (1 disruption every 66

discharges)discharges) more than 5000 discharges before reaching the “cold more than 5000 discharges before reaching the “cold

dust” safety limitdust” safety limit

Group comments:Group comments:-It seems difficult to guarantee ELMs energy <0.5 MJ/m-It seems difficult to guarantee ELMs energy <0.5 MJ/m22

(see Russian experiments*)(see Russian experiments*)-1 disruption every 66 discharges looks optimistic-1 disruption every 66 discharges looks optimistic-Issue of “hot dust” not sufficiently addressed -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


of ? slides


• 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 It is necessary to define, test and assess method(s) to remove dust during maintenance phases.during maintenance phases.

Due to uncertainties (mainly on mitigation of ELMs), it is recommended Due to uncertainties (mainly on mitigation of ELMs), it is recommended to develop, test and assess methods to measure erosion in the VV. In 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 this way it will be possible, based on estimates of the relationship between erosion and dust accumulation, to decide whether or not to between erosion and dust accumulation, to decide whether or not to proceed with dust removal before the foreseen maintenance.proceed with dust removal before the foreseen maintenance.


of ? slides


• General recommendations for dust (2/2):General recommendations for dust (2/2):

The group considered that measuring low quantities of dusts spread over large The group considered that measuring low quantities of dusts spread over large surfaces, at high temperature and in a nuclear fusion environment is very 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 demanding and stressed the need 1) to carry out an exhaustive review of potential low quantity dust measurement techniques,2) to investigate possible potential low quantity dust measurement techniques,2) to investigate possible cleaning techniques in order to guarantee that the divertor region(PFCs surface) cleaning techniques in order to guarantee that the divertor region(PFCs surface) is almost “dust free” during operation of the machine.is almost “dust free” during operation of the machine.

Furthermore, keeping in mind that the development of such a technique is very 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 challenging, it is also recommended to proceed in parallel with the assessment of explosion mitigation methods (inert gas injection) and possible design of explosion mitigation methods (inert gas injection) and possible design enhancements to limit air ingress or to improve the sustainability of the VV to enhancements to limit air ingress or to improve the sustainability of the VV to the transient peak pressure (mechanical design of the vessel itself) (the transient peak pressure (mechanical design of the vessel itself) ( covered covered

by F4E).by F4E).


of ? slides


• Tritium inventory:Tritium inventory:

Estimations* based on: Estimations* based on:

- Databases (wall fluxes, erosion/deposition rates, saturation level - Databases (wall fluxes, erosion/deposition rates, saturation level versus material(C, Be, W))versus material(C, Be, W))

- Code calculations (D+T fluxes, transport codes)- Code calculations (D+T fluxes, transport codes)

Safety tritium limit could be reached after a few hundred shots (mix: C, Safety tritium limit could be reached after a few hundred shots (mix: C, Be,W)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 ELMs

- potential non-mitigated disruptions- potential non-mitigated disruptions

*Recent Analysis of Key Plasma Wall Interactions Issues for ITER, J. Roth et al, PSI 18 Toledo, May 2008


of ? slides


• General recommendations for tritium:General recommendations for tritium:

Studies on development of ITER scenarios in view of minimising tritium Studies on development of ITER scenarios in view of minimising tritium trapping (e.g DD sequence at the end of each DT pulse) trapping (e.g DD sequence at the end of each DT pulse)

Define, test and assess method/s to detritiate between and during the Define, test and assess method/s to detritiate between and during the foreseen maintenance phases.foreseen maintenance phases.

Develop methods to measure the fuel retention already in the non Develop methods to measure the fuel retention already in the non activated phase globally by gas balance and to analyse locally and activated phase globally by gas balance and to analyse locally and time resolved the amount and distribution of retained fuel (tritium) in time resolved the amount and distribution of retained fuel (tritium) in

the VV during , in between shots or during nights/weekends.the VV during , in between shots or during nights/weekends.


11of ? slides


• Recommendations for 2009 programmes:Recommendations for 2009 programmes:

Selection of relevant techniques (Pro&Cons analysis) according to the Selection of relevant techniques (Pro&Cons analysis) according to the following criteria: following criteria:

- Performances, level of assessment- Performances, level of assessment- Relevancy with respect to ITER constraints- Relevancy with respect to ITER constraints

The goal in 2009 is to perform feasibility studies in order to assess the The goal in 2009 is to perform feasibility studies in order to assess the possibility to implement those relevant techniques on ITERpossibility to implement those relevant techniques on ITER

In case of positive outcome an R&D proposal based on a project In case of positive outcome an R&D proposal based on a project oriented approach shall be providedoriented approach shall be provided


12of ? slides


DUST INVENTORY

Recommendation 2009 Ressources

IVVS system: assessment of possible enhancements in view of significantly improving the depth resolution of net erosion measurements

1.5 ppy 30 k€ for hardware

DEM system: to perform a review of possible laser-based techniques which could be employed together with a detailed feasibility study for the possible integration on ITER

1.5 ppy

To check the possibility to include markers (coupled with spectroscopy measurements) in the divertor PFCs

0.5 ppy

To perform a feasibility study in order to check a potential port-plug application of the Speckle interferometry on ITER


To review the spectroscopy diagnostics foreseen on ITER to check their adequacy for erosion measurements ( including marker erosion detection)

0.5 ppy

To review all possible measurement methods and propose an R&D program to allow the measurement of small quantities spread on a large surface

0.5 ppy

TOTAL 6 ppy+60 k€ for hardware


13of ? slides


DUST REMOVAL


Fluid based technique: to perform an impact study (PFCs deconditioning, drying and reconditioning procedures, wastes...)

0.5 ppy

Photo-cleaning method: to quantify the gain when compared to simple vacuum cleaning

0.5 ppy

To assess the possibility (inc integration issues) of using a photo-cleaning method for removing the dusts deposited on the divertor surfaces

1.5 ppy

TOTAL 2.5 ppy


14of ? slides


TRITIUM INVENTORY


To perform a feasibility study (integration) on a port-plug based scanning laser system


To perform a feasibility study on a Remote Handle based scanning laser system




15of ? slides


TRITIUM REMOVAL


To evaluate the possibility to mitigate T retention by isotope exhange, e.g. of the efficiency of ending each DT pulse by a DD sequence

0.5 ppy

Bulk heating under oxidizing atmosphere: to quantify the technical and cost impact on the tritium plant and other systems

0.5 ppy

Divertor heating under vacuum: to perform a feasibility study 1 ppy Surface heating(photonic method): to perform a feasibility study envisaging a possible implementation on the IVVS carrier or a robotic arm system

1 ppy

Surface ablation: to perform a feasibility study on a Remote Handled application (including waste collection)

1 ppy 30 k€ for hardware



16of ? slides


• Conclusion (1/2):Conclusion (1/2):

Significant uncertainties on the predictions for dust Significant uncertainties on the predictions for dust production and tritium trapping in ITER identifiedproduction and tritium trapping in ITER identified

Potential techniques have been reviewed and the most Potential techniques have been reviewed and the most relevant selectedrelevant selected

It is proposed to perform feasibility studies in 2009. In It is proposed to perform feasibility studies in 2009. In case of positive outcome a detailed project proposal case of positive outcome a detailed project proposal shall be proposed.shall be proposed.


17of ? slides


• Conclusion (2/2):Conclusion (2/2):

Proposal recommended by EFDA-STAC (Brussels-Proposal recommended by EFDA-STAC (Brussels-25/09/2008)25/09/2008)

Programme proposal endorsed by EFDA steering Programme proposal endorsed by EFDA steering committee (JET-06/10/2008)committee (JET-06/10/2008)

Call for proposal is being launched after sharing of Call for proposal is being launched after sharing of tasks between F4E and EFDA.tasks between F4E and EFDA.


18of ? slides



19of ? slides

DUST AND TRITIUM MANAGEMENT DUST AND TRITIUM MANAGEMENT

Dust accumulation areas


20of ? slides


IVVS SCANNING HEAD

Optical fiber

Pout


21of ? slides



22of ? slides

DUST AND TRITIUM MANAGEMENTDUST AND TRITIUM MANAGEMENTDeadlines:

– Port plug mounted systems:Final design agreed among all stakeholders: end 2014

– Divertor cassette mounted systemsDelivery to ITER: end 2016

– In-Vessel mounted systemsDelivery to ITER: end 2014

– Adaptation or use of space on the IVVS systemFinal design agreed among all stakeholders: end 2016


23of ? slides


ELM

Disruption level, w > 2.2MJ/m2

CFC fibers erosion as a function of surface energy density

Ero

sio

n (

Hp

itch

-HP

AN),

m


24of ? slides


Laser beam

Scanning mirror

Possible design

Laser

5mmDivergence

60mm lensBeam expansion=10

60mm lensf=15m

Scanningmirror

Vacuum

Sphericalmirror

Divertor

Target

Edge mirrorC,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


25of ? slides


DEM system for ITER


26of ? slides


Galvanometric scan

Fiber for laser input


27of ? slides


f. le guern dust&tritium pwi am frascati 27-29 oct 2008 dust and tritium management

Documents

slides dust

removal of dust

tritium management slide

guern dusttritium pwi

iter slide

tritium management safety

tritium management decision

programmes conclusion