H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 1 Lithium Experiments in the NSTX Boundary Physics Program H.W.Kugel, M.Bell, R.Kaita, R.Majeski, C.H.Skinner, V.Soukhanovskii, D.Stotler (PPPL), R.Maingi (ORNL), T.Rognlien (LLNL), and M.Ulrickson (SANDIA). This work supported by US DOE Contract DE-AC02-76CH03073

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 2 TFTR demonstrated the benefit of lithium coating carbon limiter - Strong edge pumping (reduction of recycling) - Improvement in energy confinement (x2) Particle Control 1. Lithium Pellet Injection (FY’04) - Use large capacity and multiple pellet capability 2. Lithium Evaporator (Fy’05) - CDX-U developing modular e-beam evaporators - Use several evaporators to cover NSTX divertor regions - Benefit from CDX-U/LTX research to optimize substrate possible change from carbon PFCs in FY’07 Particle Control and Power Handling 3. Liquid Lithium Surface Module (FY’08) - Potential for both power and particle handling NSTX Lithium Experiments Will Focus on Particle Control (FY04) & Power Handling (FY08)

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 3 NSTX Lithium Pellet Injection FY’04 Injector being installed for operation in FY’04 - Lithium, boron, carbon, or micro-pellet ensembles - Controllable velocity ( m/s) with 8 pellets /shot - Large pellet mass capability (>10 mg) Li Pellet Injection Experiments - Make contact with lithium pellet database - Characterize lithium pellet behavior in ST’s

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 4 LTX R&D Facilitates NSTX Lithium Evaporator FY’05 E-beam sources Lithium-coated, heated, plasma-aligned first wall Solid lithium evaporation source Recirculating lithium limiter- Plasma Technology (used also as evaporation source) In LTX, e-beam system will deposit lithium on a W (or Mo) coated copper wall before every discharge Electron-beam deposition – Å coating applied between discharges –Dep rates of 1000 Å /40 sec. at 1 m radius demonstrated »NSTX relevant –Self contained, insertable version also under development »NSTX relevant –Wall temperature of ~250 o C will keep lithium coating molten Heat-conducting copper shell will reduce local temperature excursions –Limit evaporation

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 5 Implementation of NSTX Lithium Wall Coating System 1) Install e-beam probe for deposition over selected divertor & passive plate regions. 2) Start with Li deposition on existing graphite PFC’s. Deposit 1000Å of lithium and withdraw the e-beam probe. –Similar to the insertable Ti getters used in PDX, PBX-M, but time scale is different »Few 10’s of seconds for 1000Å coating »Cycle time is dominated by insertion/removal of e-beam. -Coat before every shot shots  0.1 mm accumulation 3) Later replace existing graphite PFC tiles with suitable PFC upgrade as required. Evaporator Probe Shown is an Upper Divertor Concept. Upper & Lower Divertor Concepts will be investigated.

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 6 Particle Pumping by Lithium Coatings Wall: –Area of passive plates is ~1.5 x 10 5 cm 2. –Volume of 1000Å coating: 1.5 cm 3 (~ 6 x atoms) – ~ 6 x particles in an NSTX discharge –Wall has the capacity to pump the discharge for many particle confinement times Divertor: –Area ~ 3.6 x 10 4 cm 2. –1.5 x atoms. –Less capacity. »Requires strike point sweeping to pump the divertor.

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 7 Liquid Lithium Surface Module Will Address Important Reactor Issues Development under aegis of ALIST group of VLT A potential solution for both power and particle handling -tantalizing possibilities for advanced regimes -Liquid Li tray in CDX-U dramatically reduced recycling Modules ~ 1 m 2 close to plasma Flow liquid Li at ~7-12 m/s to avoid evaporation at full power The design will be based on edge and MHD modeling of CDX-U,LTX, NSTX data Installation in FY’08 C.Eberele, ORNL

H. W. Kugel 45 th APS DPP Meeting Oct 27-31, 2003, Albuquerque, NM 8 Summary and Conclusions NSTX will begin lithium experiments with pellet injection, followed by lithium evaporation, and then operation with a liquid lithium surface module. Lithium Pellet Injection will characterize Li pellet behavior in ST’s (FY’04). Higher yield film deposition techniques will use a between-shot lithium evaporator to coat the passive plate and divertor tiles (FY05). A Liquid Lithium Surface Module (LLSM) will address active pumping and assist with power handling (FY’08). The design will be based on edge and MHD modeling of CDX-U,LTX, & NSTX data.