Study of hydrogen isotope interaction with beryllium and carbon surfaces under their simultaneous exposure to stationary and powerful pulsed plasma

Formation of films on ITER first wall and divertor surfaces as a result of simultaneous interaction of H-isotopes with Be and C atoms was investigated in experiments simulating normal ITER operation and plasma disruptions. Under normal conditions, one can observe a continuous formation, growth and flaking of mixed Be+ C films. Their Be/C atomic ratio varies from 1/2 to 2 (Be2C). At high doses of deuteron irradiation (10(24) m(-2)) ratio D/(Be + C) approximate to 0.02-0.06. Under plasma disruption simulation, the D-concentration in mixed Be + C films is an order on magnitude smaller than under exposure to a stationary D-plasma. (C) 2004 Elsevier B.V. All rights reserved.