8.5 T-Related Issues on the In-Vessel T Inventory
157
In addition, one cannot detect T existing inside of solids deeper than a few μm from
their surfaces. The easy isotopic exchange of T with ubiquitous hydrogen in water
and hydrocarbons at materials surfaces can significantly affect the analysis and also
gives concerns in safety.
8.6 Summary
Main subjects of PMI are (1) power load to PFM, (2) hydrogen retention and recycling, (3) erosion and deposition and accompanied material transport, (4) their influence on plasma confinement. Compared to a fusion reactor, injecting hydrogen flux
to PFM in current tokamaks is far less. Accordingly, power load given by the fuel
particles was not high enough to give appreciable influences on hydrogen recycling,
erosion/deposition and their mutual relations, for example, fuel retention in deposits
and formation of dusts. Hence, first three subjects have been separately studied as
given in this chapter, while the fourth subject in the present tokamak is not so significant to allow systematic studies except dust formation and some changes in optical
emissions in front of PFM.
In PMI in a fusion reactor, first three subjects must be strongly correlated with each
other and large power load would change the appearance of PMI as suggested in the
text. Furthermore, fueling T requires additional considerations on T safety, fuel selfsufficiency, and neutron irradiation effects. This chapter summarizes observations
of PMI in current tokamaks with C-wall and metallic wall and suggests required
studied considering significant increase of power load, incident particle flux of fuels
to PFM and neutron effects.
References
1. A. Kreter, Reactor-relevant plasma-material interaction studies in linear plasma devices. Fusion
Sci. Technol. 59, 51–56 (2011)
2. J. Rapp, The challenges of plasma material interactions in nuclear fusion devices and potential
solutions. Fusion Sci. Technol. 72, 211–221 (2017)
3. R.A. Pitts, G. Arnoux, M. Beurskens et al., The impact of large ELMs on JET. J. Nucl. Mater.
390–391, 755–759 (2009)
4. A. Huber, G. Arnoux, M.N.A. Beurskens et al., Radiation loads onto plasma-facing components
of JET during transient events–experimental results and implications for ITER. J. Nucl. Mater.
415, S821–S827 (2011)
5. N. Den Harder, S. Brezinsek, T. Pütterich, et al., ELM-resolved divertor erosion in the JET
ITER-Like wall. Nucl. Fusion 56(9), 026014 (2016)
6. G. Arnoux, B. Bazylev, M. Lehnen, et al., Heat load measurements on the JET first wall during
disruptions, J. Nucl. Mater. 415, S817–S820 (2011)
7. V. Philipps, T. Tanabe, Y. Ueda et al., Molybdenum test limiter experiments in TEXTOR. Nucl.
Fusion 34, 1417–1429 (1994)
8. R. Dux, A. Herrmann, A. Kallenbach, Plasma surface interaction with tungsten in ASDEX
Upgrade. J. Nucl. Mater. 337–339, 852–856 (2005)
157
In addition, one cannot detect T existing inside of solids deeper than a few μm from
their surfaces. The easy isotopic exchange of T with ubiquitous hydrogen in water
and hydrocarbons at materials surfaces can significantly affect the analysis and also
gives concerns in safety.
8.6 Summary
Main subjects of PMI are (1) power load to PFM, (2) hydrogen retention and recycling, (3) erosion and deposition and accompanied material transport, (4) their influence on plasma confinement. Compared to a fusion reactor, injecting hydrogen flux
to PFM in current tokamaks is far less. Accordingly, power load given by the fuel
particles was not high enough to give appreciable influences on hydrogen recycling,
erosion/deposition and their mutual relations, for example, fuel retention in deposits
and formation of dusts. Hence, first three subjects have been separately studied as
given in this chapter, while the fourth subject in the present tokamak is not so significant to allow systematic studies except dust formation and some changes in optical
emissions in front of PFM.
In PMI in a fusion reactor, first three subjects must be strongly correlated with each
other and large power load would change the appearance of PMI as suggested in the
text. Furthermore, fueling T requires additional considerations on T safety, fuel selfsufficiency, and neutron irradiation effects. This chapter summarizes observations
of PMI in current tokamaks with C-wall and metallic wall and suggests required
studied considering significant increase of power load, incident particle flux of fuels
to PFM and neutron effects.
References
1. A. Kreter, Reactor-relevant plasma-material interaction studies in linear plasma devices. Fusion
Sci. Technol. 59, 51–56 (2011)
2. J. Rapp, The challenges of plasma material interactions in nuclear fusion devices and potential
solutions. Fusion Sci. Technol. 72, 211–221 (2017)
3. R.A. Pitts, G. Arnoux, M. Beurskens et al., The impact of large ELMs on JET. J. Nucl. Mater.
390–391, 755–759 (2009)
4. A. Huber, G. Arnoux, M.N.A. Beurskens et al., Radiation loads onto plasma-facing components
of JET during transient events–experimental results and implications for ITER. J. Nucl. Mater.
415, S821–S827 (2011)
5. N. Den Harder, S. Brezinsek, T. Pütterich, et al., ELM-resolved divertor erosion in the JET
ITER-Like wall. Nucl. Fusion 56(9), 026014 (2016)
6. G. Arnoux, B. Bazylev, M. Lehnen, et al., Heat load measurements on the JET first wall during
disruptions, J. Nucl. Mater. 415, S817–S820 (2011)
7. V. Philipps, T. Tanabe, Y. Ueda et al., Molybdenum test limiter experiments in TEXTOR. Nucl.
Fusion 34, 1417–1429 (1994)
8. R. Dux, A. Herrmann, A. Kallenbach, Plasma surface interaction with tungsten in ASDEX
Upgrade. J. Nucl. Mater. 337–339, 852–856 (2005)