7.9 Summary
129
In a fusion reactor, H injected in PFM with energy gives additional processes. They
appear as, reflection, damage formation including blistering, reemission of atoms and
molecules, diffusion and trapping and influence of damages on them like radiation
enhanced diffusion, super-permeation, and so on. In addition, mixture of D and T
as fusion fuel brings isotope effects in these processes, owing to their large mass
difference, which is not easy to study because handling such large amount of T used
in a reactor or even in ITER is impossible in any laboratories at present. Therefore,
results obtained for H and D should be extrapolated to D and T.
In this chapter, above mentioned fundamental processes are introduced with a
little detail, for foreseeing or understanding what the hydrogen recycling in a reactor
likely to be. Although simulation would help this, the processes are so synergistic
that the present simulation is hard to cover all important processes.
References
1. M. Shimada, R.A. Pitts, Wall conditioning on ITER. J. Nucl. Mater. 415, S1013–S1016 (2011)
2. T. Tanabe, Interactions of Hydrogen with Fusion Reactor Materials, National Research Nuclear
(University MEPhI, Moscow, 2019). ISBN 978-5-7262-2632-3
3. T. Nakao, Chapter 4, Burning Plasma, in Tritium: Fuel for Fusion Reactors, ed. by T. Tanabe
(Springer Japan, 2017), pp. 73–92, ISBN 978-4-431-56458-4
4. A. Kallenbach, M. Bernert, R. Dux et al., Impurity seeding for tokamak power exhaust: from
present devices via ITER to DEMO. Plasma Phys. Control. Fusion 55, 124041 (2013)
5. T. Tanabe, Tritium fuel cycle in ITER and DEMO: issues in handling large amount of fuel. J.
Nucl. Mater. 438, S19–S26 (2013)
6. T. Tanabe, Review of hydrogen retention in tungsten, Phys. Scr. T159(12), 014044 (2014)
7. T. Tanabe, Surface barrier for tritium permeation. Fusion Technol. 28, 1278–1283 (1995)
8. T. Tabata, R. Ito, Y. Itikawa, et al., Data on the backscattering coefficient of light ions from solids,
Rep. IPPJ-AM-18 (1981), (R. Ito, T. Tabata, T. Itoh, Data ow the backscattering coefficients
of light ions from solids (A Revision) Rep. IPPJ AM-41, 1985)
9. J. Roth, A. Kirschner, W. Bohmeyer et al., Flux dependence of carbon erosion and implication
for ITER. J. Nucl. Mater. 337–339, 970 (2005)
10. J.W. Davis, A A. Haasz, Reemission of deuterium atoms from Mo, Ta and W during D + -
irradiation, J. Nucl. Mater. 223, 312–315 (1995)
11. J.W. Davis, A.A. Haasz, Reemission and thermal desorption of D°, D2 and CD4 from graphite.
J. Nucl. Mater. 220–222, 832–835 (1995)
12. P. Franzen, E. Vietzke, A.A. Haasz et al., Atomic re-emission of hydrogen from pure and
boronized graphites at temperatures above 1000 K. J. Nucl. Mater. 196–198, 967–971 (1992)
13. A. Pospieszczyk, P. Mertens, G. Sergienko et al., In situ measurement and modeling of hydrogen
recycling and transport processes–the role of molecules. J. Nucl. Mater. 266–269, 138–145
(1999)
14. T. Tanabe, H. Hirano, S. Imoto, Re-emission and thermal desorption of deuterium implanted
in Ni near room temperature, J. Nucl. Mater. 151, 38–47 (1987)
15. T. Tanabe, Y. Furuyama, S. Imoto, Reemission and permeation of deuterium implanted into
metals. J. Nucl. Mater. 122&123, 1563–1567 (1984)
16. M. Yamawaki, N. Chitose, V. Bandurko et al., Impact of surface phenomena in metals on
hydrogen isotope permeation. Fusion Eng. Design 28, 125–130 (1995)
17. N. Enomoto, S. Muto, T. Tanabe et al., Grazing-incidence electron microscopy of surface
blisters in single-and polycrystalline tungsten formed by H+, D+ and He+ irradiation. J. Nucl.
Mater. 385, 606–614 (2009)
129
In a fusion reactor, H injected in PFM with energy gives additional processes. They
appear as, reflection, damage formation including blistering, reemission of atoms and
molecules, diffusion and trapping and influence of damages on them like radiation
enhanced diffusion, super-permeation, and so on. In addition, mixture of D and T
as fusion fuel brings isotope effects in these processes, owing to their large mass
difference, which is not easy to study because handling such large amount of T used
in a reactor or even in ITER is impossible in any laboratories at present. Therefore,
results obtained for H and D should be extrapolated to D and T.
In this chapter, above mentioned fundamental processes are introduced with a
little detail, for foreseeing or understanding what the hydrogen recycling in a reactor
likely to be. Although simulation would help this, the processes are so synergistic
that the present simulation is hard to cover all important processes.
References
1. M. Shimada, R.A. Pitts, Wall conditioning on ITER. J. Nucl. Mater. 415, S1013–S1016 (2011)
2. T. Tanabe, Interactions of Hydrogen with Fusion Reactor Materials, National Research Nuclear
(University MEPhI, Moscow, 2019). ISBN 978-5-7262-2632-3
3. T. Nakao, Chapter 4, Burning Plasma, in Tritium: Fuel for Fusion Reactors, ed. by T. Tanabe
(Springer Japan, 2017), pp. 73–92, ISBN 978-4-431-56458-4
4. A. Kallenbach, M. Bernert, R. Dux et al., Impurity seeding for tokamak power exhaust: from
present devices via ITER to DEMO. Plasma Phys. Control. Fusion 55, 124041 (2013)
5. T. Tanabe, Tritium fuel cycle in ITER and DEMO: issues in handling large amount of fuel. J.
Nucl. Mater. 438, S19–S26 (2013)
6. T. Tanabe, Review of hydrogen retention in tungsten, Phys. Scr. T159(12), 014044 (2014)
7. T. Tanabe, Surface barrier for tritium permeation. Fusion Technol. 28, 1278–1283 (1995)
8. T. Tabata, R. Ito, Y. Itikawa, et al., Data on the backscattering coefficient of light ions from solids,
Rep. IPPJ-AM-18 (1981), (R. Ito, T. Tabata, T. Itoh, Data ow the backscattering coefficients
of light ions from solids (A Revision) Rep. IPPJ AM-41, 1985)
9. J. Roth, A. Kirschner, W. Bohmeyer et al., Flux dependence of carbon erosion and implication
for ITER. J. Nucl. Mater. 337–339, 970 (2005)
10. J.W. Davis, A A. Haasz, Reemission of deuterium atoms from Mo, Ta and W during D + -
irradiation, J. Nucl. Mater. 223, 312–315 (1995)
11. J.W. Davis, A.A. Haasz, Reemission and thermal desorption of D°, D2 and CD4 from graphite.
J. Nucl. Mater. 220–222, 832–835 (1995)
12. P. Franzen, E. Vietzke, A.A. Haasz et al., Atomic re-emission of hydrogen from pure and
boronized graphites at temperatures above 1000 K. J. Nucl. Mater. 196–198, 967–971 (1992)
13. A. Pospieszczyk, P. Mertens, G. Sergienko et al., In situ measurement and modeling of hydrogen
recycling and transport processes–the role of molecules. J. Nucl. Mater. 266–269, 138–145
(1999)
14. T. Tanabe, H. Hirano, S. Imoto, Re-emission and thermal desorption of deuterium implanted
in Ni near room temperature, J. Nucl. Mater. 151, 38–47 (1987)
15. T. Tanabe, Y. Furuyama, S. Imoto, Reemission and permeation of deuterium implanted into
metals. J. Nucl. Mater. 122&123, 1563–1567 (1984)
16. M. Yamawaki, N. Chitose, V. Bandurko et al., Impact of surface phenomena in metals on
hydrogen isotope permeation. Fusion Eng. Design 28, 125–130 (1995)
17. N. Enomoto, S. Muto, T. Tanabe et al., Grazing-incidence electron microscopy of surface
blisters in single-and polycrystalline tungsten formed by H+, D+ and He+ irradiation. J. Nucl.
Mater. 385, 606–614 (2009)