Examination of deposited layers composition on the tokamak T11-M Dis - charge chamber constructional elements after two-year operation with lithium limiter

Full text of publication follows: The results of the surface analysis of internal structural elements of the T11-M tokamak discharge chamber after two-year operation with lithium limiter are presented [1,2]. The surface condition of the discharge chamber molybdic wall and an internal steel surface of the diagnostic ports have been investigated. X-ray microanalysis of the deposited layers on the first wall surface has shown, that deposited layer includes M0 in the main and a small amount of Cu. In a composition of deposited layer on the diagnostic ports surface, except the above-named elements, there is Fe in a small amount. Because of the instrumental restrictions of this method of analysis, an opportunity of detection of the lithium traces has missed. X-ray diffractometer analysis of the deposited layers on the first wall surface has detected a mixture of several phases. The main phase is Li2CO3, one third from all deposited substance is Li2MoO4, there is also LiOH-H2O phase. The deposited layer on the diagnostic ports surface consists of LiOH-H2O phase in the main, there is also Li2CO3 phase. The results of X-ray analysis of a dust probe from the B4C coated graphite limiter surface have not detected whatever extra phases, except a crystalline boron carbide phase. [1] V.B. Lazarev, E.A. Azizov et al., Compatibility of the Lithium Capillary Limiter with Plasma in T-11M, 26. EPS Conf. on Contr. Fusion Plasma Physics, ECA, vol. 231, pp. 845-848, 1999; [2] V.A. Evtikhin, I.E. Lyublinski, A.V. Vertkov et al., Technology Aspects of Lithium Capillary pore Systems Application in Tokamak Device, SOFT-21 (Madrid), A-37, 2000. (authors)