(FT/P2-15) Main Results and Prospects of Lithium Capillary-Porous System Investigation as Tokamak Plasma Facing Material

I.E. Lyublinski1), M.L. Apicella2), E.A. Azizov3), V. Balakirev1), V.A. Evtikhin1), D.J. Ionov1), G. Mazzitelli2), S.V. Mirnov3), I.L. Tazhibaeva4), A.V. Vertkov1), V.A. Vershkov5)
1) Federal State Unitary Enterprise Red Star, Moscow, Russian Federation
2) Associazione Euroatom-ENEA sulla Fusione, C.R. Frascati, Roma, Itali
3) Troitsk Institute for Innovation and Fusion Research, Troitsk, Moscow Region, Russian Federation
4) Institute of Atomic Energy of National Nuclear Center, Kurchatov, Kazakhstan
5) Nuclear Fusion Institute RRC “Kurchatov Institute”, Moscow, Russian Federation

Abstract.  Concept of lithium fusion reactor has been offered in FEC-16 and lithium Capillary-Porous Systems (CPS) is the key element of its realization. Experiments in T-11M tokamak with lithium CPS based rail-type limiters have been started in 1998 for the purpose to prove the compatibility of lithium CPS with tokamak boundary plasma. Further stage was the beginning of liquid limiter tests in Italian tokamak FTU in 2005. The main reasons of this investigation were confirmation of CPS ability to lithium surface renewal and lithium confinement during normal plasma operation and in disruption, possibility for withstanding of high power flux on the limiter surface without damage in real tokamak condition with ohmic plasma heating mode and with additional heating. Litization effect on plasma discharge parameters of all metallic and carbon-free tokamak has been investigated. Experiments on inner-wall litization of graphite containing camera of T-10 tokamak with application of CPS based unit have been also started in 2006. All this experiments have allowed to solve the problems in MHD stability of liquid lithium film in tokamak conditions, study of lithium CPS compatibility with tokamak boundary plasma, demonstrate the positive lithium effect on plasma parameters and determine the next steps on further activity in this area. At the same time the promising results of experiments on the lithium CPS serviceability and possibility for withstanding of steady-state (up to 3 hours) high power flux ( 1 - 10MW/m2) and plasma disruption effect has been demonstrated. The progress in development of lithium technology allows deciding the problems in the development of projects of Steady-State Operating Lithium Limiters (SLL) for FTU and T-15, lithium divertor for tokamak KTM. The first stage of this activity is development and experimental study at power flux up to 10MW/m2 of the single-element prototype of SLL/divertor with systems for surface temperature stabilization in the range of 350 - 550o C and controllable lithium supply. SLL/divertor prototype structure, operating parameters and new tungsten-based CPS are presented. Safety analyses and critical aspects of prototype technology are considered. Investigations on structure material compatibility with lithium in DEMO-type tokamak conditions have allowed for proving the possibility of lithium application in fusion reactor.

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