1. 6 th EU PWI TF Meeting Madrid, Oct. 2007 1 Tritium Inventory in ITER: Laboratory data and extrapolation from tokamaks Th Loarer, J Roth, S Brezinsek, A Kirschner, M Mayer, R Neu, V Philipps, V Rohde, M Rubel and E Tsitrone Outline - How to extrapolate ? - Implantation - Codeposition Conclusion

2. 6 th EU PWI TF Meeting Madrid, Oct. 2007 2 Tritium Tritium Inventory Document the tritium co-deposition, implantation and diffusion properties for Be, C, W, including the dependence on substrate temperature and their contribution to the expected tritium inventory in ITER Be R. Doerner, M. Mayer, K. Schmid P. Coad C M. Mayer W. Jacob J. Roth V. Philipps W V. Alimov J. Roth M. Mayer Document and explain apparent differences in the results of Alcator C-Mod and ASDEX Upgrade / or dedicated laboratory experiments concerning the behaviour of high-Z PFCs J. Roth, V. Alimov (O.Ogorodnikova) G. Wright R. Neu Tritium Inventory in ITER: Laboratory data and extrapolation from tokamaks

3. 6 th EU PWI TF Meeting Madrid, Oct. 2007 3 Extrapolation from tokamak experience Two distinct forms of tritium retention 1 - A dynamic inventory (Short term retention) - Transient particle implantation over the whole vessel area. (Vary from 1 to 4 respectively for C and Be as observed on JET in limiter configuration.) This dynamic retention is more or less recovered in between the discharges in the actual tokamaks. 2 - A continuous growing inventory (depending on the material) - implantation (including diffusion and migration in depth) - co-deposition.

4. 6 th EU PWI TF Meeting Madrid, Oct. 2007 4 Implantation: Saturation or diffusion and trapping 1000 discharges: 70g T in CFC 2g T in Be 2g T in W Extrapolation from plasma scenario and laboratory data

5. 6 th EU PWI TF Meeting Madrid, Oct. 2007 5 Extrapolation from plasma scenario and laboratory data Co-deposition: Erosion and tritium concentration in deposits D/C D/Be D/W D (at. fraction)

6. 6 th EU PWI TF Meeting Madrid, Oct. 2007 6 Plasma scenario from Kukushkin et al.

7. 6 th EU PWI TF Meeting Madrid, Oct. 2007 7 Inventory for present material choice CFC in divertor dominates tritium retention Be co-deposition needs to be taken into account W controversial with US due to assumptions for wall fluxes

8. 6 th EU PWI TF Meeting Madrid, Oct. 2007 8 All-CFC reaches tritium limit in less than 25 discharges All-W eliminates tritium problem, but n- effects need to be considered Inventory for all-C and -W in ITER

9. 6 th EU PWI TF Meeting Madrid, Oct. 2007 9 n-irradiation creats additional traps for tritium in the bulk input parameter for diffusion/trapping codes Urgently Needed: Improvement in trapping and retention modelling Experimental investigations on n-irradiated materials Estimates on n-effect on inventory in W

10. 6 th EU PWI TF Meeting Madrid, Oct. 2007 10 One possible explanation are plasma impurities, largely B (~1 %), that are present in the C-Mod plasma and in the first 500 nm Mo tiles. Overall, in both high-Z devices the campaign integrated retention on D is small, much smaller than for carbon or boron co-deposition. Explain apparent differences in the results of Alcator C-Mod and ASDEX Upgrade Alcator C-mod, MoASDEX Upgrade, W Gas balance Variation between net outgassing and up to 50% retention, linear with number of discharges < 10% retention, (to be confirmed) Post- mortem 1 %< 0.2 % retention (to be confirmed) Modelling1-2 % retention, linear with number of discharges

11. 6 th EU PWI TF Meeting Madrid, Oct. 2007 11 Tritium Inventory in ITER: Laboratory data and extrapolation from tokamaks Draft report sent to ITER and US colleagues end of Aug. 2007 Final report submitted to ITER on Sept. 14, 2007