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Review of Wall Conditioning and Wall Materials for Fusion Research Devices

Published online by Cambridge University Press:  29 November 2013

Robert A. Langley
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Wall materials for fusion research must meet stringent requirements. The purity of a fusion plasma is critical to obtaining meaningful results during fusion plasma experiments. The concentration of impurity ions in the plasma must be kept low because impurities result in radiative losses that at best decrease the efficiency of the plasma “burn” and at worst prevent ignition completely. Radiative losses scale with the effective charge, Z, of the plasma. Radiative losses due to bremsstrahlung are proportional to Z2; those due to recombination are proportional to Z4. Figure 1 shows the impurity concentration above which ignition cannot be achieved as a function of impurity atomic number for an experimental power reactor. The advantage of using a low-Z material as the first wall of a fusion machine (i.e., as the plasma-facing material) is evident.

The major plasma impurities observed in most experiments are oxygen, carbon, and first-wall material. These impurities are introduced into the plasma by many mechanisms, including outgassing, desorption, chemical interaction, sputtering, and evaporation. Chemical and physical interactions between the first wall and the energetic hydrogenic ions produced in the plasma are important factors in impurity production. (Here “hydrogen” refers to hydrogen and its isotopes, deuterium and tritium.)

The energy contained in the plasma can be quite large (many megajoules) and can interact with the first wall on a short rime-scale (e.g., a millisecond). It is possible that no material will prove suitable for all operational scenarios. Therefore, the burden of reducing the plasma/first-wall interaction to an acceptable level rests on both plasma and materials scientists.

Type
Materials for Vacuum
Information
MRS Bulletin , Volume 15 , Issue 7 , July 1990 , pp. 42 - 46
Copyright
Copyright © Materials Research Society 1990

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References

1.Langley, R.A. and Prevender, T.S., Thin Solid Films 45 (1977) p. 235.CrossRefGoogle Scholar
2. Decontam is a nonflammable nontoxic, nonhazardous, biodegradable liquid available from Electronic Space Products International.Google Scholar
3.Dylla, H.F., J. Vac. Sci. Technol. A 6 (1988) p. 1276.CrossRefGoogle Scholar
4.Grunze, M., Ruppender, H., and Elshazly, O., J. Vac. Sci. Technol. A 6 (1988) p. 1266.CrossRefGoogle Scholar
5.LaMarche, P.H.et al., to be presented at the 16th Symposium on Fusion Technology, London, September 3-7,1990, proceedings to be published.Google Scholar
6.Dylla, H.F.et al., to be presented at the 9th Conference on Plasma-Surface Interactions, Bournemouth, England, May 20-25, 1990, proceedings to be published in J. Nucl. Mater.Google Scholar
7.O'Hanlon, J.F., A User's Guide to Vacuum Technology (Wiley, New York, 1980) p. 132 and 294.Google Scholar
8.Surface Conditioning of Vacuum Systems, edited by Langley, R. A. (AIP Conf. Proc. 199, New York, 1990).Google Scholar
9.Wells, E.R. and Postma, H., in Transactions of the National Symposium on Vacuum Technology (Macmillan, New York, 1962) p. 266.Google Scholar
10.Clausing, R.E., Transactions of the National Symposium on Vacuum Technology (Macmillan, New York, 1961) p. 345.Google Scholar
11.Simpkins, J.E., Blanchard, W.R., Dylla, H.F., and LaMarche, P.H., J. Nucl. Mater. 145-147 (1987) p. 348.CrossRefGoogle Scholar
12.Winter, J., Waelbroeck, F., and Wienhold, P., in Fusion Technology: Proceedings of the 12th Symposium, Jülich, 1982.Google Scholar
13.Sakamoto, Y.et al., J. Nucl. Mater. 93 & 94 (1980) p. 333.CrossRefGoogle Scholar
14.Oren, L. and Taylor, R.J., Nucl. Fusion 17 (1977) p. 1143.CrossRefGoogle Scholar
15.LaMarche, P.H.et al., J. Nucl Mater. 145–147 (1987) p. 781.CrossRefGoogle Scholar
16.Dylla, H.F.et al., J. Nucl Mater. 145–147 (1987) p. 48.CrossRefGoogle Scholar
17.Waelbroeck, F., Vacuum 39 (1989) p. 821.CrossRefGoogle Scholar
18.Langley, R.A., in Surface Conditioning of Vacuum Systems, edited by Langley, R.A. (AIP Conf. Proc. 199, New York, 1990).Google Scholar
19.Pontau, A.E. and Morse, D.H., J. Nucl. Mater. 141–143 (1986) p. 124.CrossRefGoogle Scholar
20.Dylla, H.F.et al., J. Nucl. Mater. 155–157 (1988) p. 15.CrossRefGoogle Scholar
21.ITER Concept Definition, Vol. 2, ITER Documentation Series, No. 3 (IAEA, Vienna, 1989) p. 288.Google Scholar
22. See, for example, Reference 21, p. 530–540.Google Scholar
23.Langley, R.A.et al., J. Nucl. Mater. 85 & 86 (1979) p. 215.CrossRefGoogle Scholar
24.Cecchi, J.L. and Knize, R.J., J. Vac. Sci. Technol. A 2 (1984) p. 1214.CrossRefGoogle Scholar
25.Langley, R.A., in Proc. IEEE 13th Symp. on Fusion Engineering, Vol. 1 (IEEE, New York, 1990) p. 522.Google Scholar
26.Ulrickson, M.et al., J. Nucl. Mater., accepted for publication.Google Scholar
27.Rebut, P.H.et al., in Proc. IEEE 13th Symp. on Fusion Engineering, Vol. 1 (IEEE, New York, 1990) p. 227.Google Scholar
28.Davis, M.J., Langley, R.A., and Prevender, T.S., Sandia National Laboratories Report SAND77-1027 (1977).Google Scholar
29.Langley, R.A. and Donhowe, J.M., J. Nucl. Mater. 63 (1976) p. 521.CrossRefGoogle Scholar
30.Mioduszewski, P.K.et al., Nucl. Fusion 26 (1986) p. 1171.CrossRefGoogle Scholar
31.Dietz, K.H.et al., in Proc. IEEE 13th Symp. on Fusion Engineering, Vol. 1 (IEEE, New York, 1990) p. 517.Google Scholar
32.Winter, J.et al., in Surface Conditioning of Vacuum Systems, edited by Langley, R.A. (AIP Conf. Proc. 199, New York, 1990).Google Scholar
33.Simpkins, J.E., Mioduszewski, P., and Stratton, L.W., J. Nucl. Mater. 111 & 112 (1982) p. 827.CrossRefGoogle Scholar
34.Dylla, H.F.et al., J. Vac. Sci. Technol. A 4 (1986) p. 1753.CrossRefGoogle Scholar
35.Murakami, M., Oak Ridge National Laboratory, private communication (February 1990).Google Scholar
36.Hackmann, J. and Uhlenbusch, J., Nucl. Fusion 24 (1984) p. 641.CrossRefGoogle Scholar
37.Bessenrodt-Weberpals, A.M., Hackmann, J., Neiswand, C., and Uhlenbusch, J., J. Nucl. Mater. 162–164 (1988) p. 432.Google Scholar
38.Langley, R.A., England, A.C., Edmonds, P.H., Hogan, J.T., and Neilson, G.H., Nucl. Fusion 26 (1986) p. 1243.CrossRefGoogle Scholar
39.Langley, R.A., Emerson, L.C., Whitley, J.B., and Mullendore, A.W., J. Nucl. Mater. 93 & 94 (1980) p. 479.CrossRefGoogle Scholar
40.Ulrickson, M.et al., J. Nucl. Mater. 133 & 134 (1985) p. 253.CrossRefGoogle Scholar
41.Winter, J., J. Nucl. Mater. 145–147 (1987) p. 131.CrossRefGoogle Scholar
42.Winter, J., J. Vac. Set. Technol. A 5 (1987) p. 2286.CrossRefGoogle Scholar
43.Langley, R.A., J. Nucl. Mater. 162–164 (1989) p. 1030.CrossRefGoogle Scholar
44.Jackson, G.L., Taylor, T.S., Peterson, P.I., and Taylor, P.L., in Surface Conditioning of Vacuum Systems, edited by Langley, R.A. (AIP Conf. Proc. 199, New York, 1990) p. 39.Google Scholar
45.Langley, R.A., Blewer, R.S., and Roth, J., J. Nucl. Mater. 76 & 77 (1978) p. 313.CrossRefGoogle Scholar
46.ITER Concept Definition, Vol. 2, ITER Documentation Series, No. 3 (IAEA, Vienna, 1989) p. 290.Google Scholar
47.Cohen, S.A., “Summary of Workshop on Innovative Technologies for Impurity Control,” January 11-12, 1990, to be published in Fusion Technol. (1990).Google Scholar