No 1 V. Philipps, SEWG Fuel retention, July 2010, Garching Joint TEXTOR, MAGNUM and PISCES experiments on retention in W and mixed W/C system V. Philipps, M. Zlobinski FZJ Jülich 1.D retention in bulk W, W coatings and mixed W/C systems under TEXTOR edge conditions, comparison with pure graphite samples under identical conditions Te ( eV), shifted Maxwellian energy distribution D eV 2-4 % C, 1-2 % O: 280 – 700eV (C 3+, O 3+) Flux range: x /m 2 s Fluence: 5 – 10 x /m 2 2. W samples exposed in RF plasma (TOMAS) and GDC (PADOS) 3. Retention under Magnum (PILOT) exposure conditions Also: exploration of spot laser desorption versus normal TDS (for TEXTOR apllication)

No 2 V. Philipps, SEWG Fuel retention, July 2010, Garching W Mo C LCFS (46cm) Erosion dominated Deposition dominated Plasma near edge, highest D-fluence Far SOL, deposition dominated Polycrstalline Mo, W, high purity, (Good Fellow), EK98 graphite No annealing Previous exposures of bulk W, Mo and C in TEXTOR Decreasing flux λ F 1.2 cm

No 3 V. Philipps, SEWG Fuel retention, July 2010, Garching Tangential view, WI light Hα light side view Spectroscopic side view observations

No 4 V. Philipps, SEWG Fuel retention, July 2010, Garching Retention in polished bulk W, Mo and EK98 graphite from upper exposed edge ( slow TDS) Fluence : D/m 2 (from mapped edge diagnostic (under revision) 550K < Tmax < 650 K (limiter preheated to 550 K) Unpublished TDS 24 months after exposure, storage in air

No 5 V. Philipps, SEWG Fuel retention, July 2010, Garching MIT ITPA workshop and report

No 6 V. Philipps, SEWG Fuel retention, July 2010, Garching D retention in JET W-coatings Recent retention measurements on W coated JET samples CMSII W layers with interlayer of Mo (2-3 µm) before exposure parallel orientation, µm, before exposure Samples : From C. Ruset Romania ASSOCIATION EURATOM / MEdC CFC (DMS780) without coating as reference CFC with µm and with µm W layer exposed under identical plasma conditions fibre orientations: parallel and perpendicular

No 7 V. Philipps, SEWG Fuel retention, July 2010, Garching Side view: Top view: tokamak outside (LFS) I E Limiter configuration toroidal radial poloidal toroidal ion drift side electron drift side W layer: µm W layer: µm uncoated CFC W layer: µm W layer: µm fibre orientation: perpendicular parallel perp LCFS 4-6

No 8 V. Philipps, SEWG Fuel retention, July 2010, Garching Exposure in TEXTOR Surface temperature: T start (TC data) : C T rise during shot: C (spot pyrometer on limiter tip) T max < 500K ohmic discharges 355 kA, = / m 3, 43 shots 0.5 cm behind LCFS (6 shots 1.3 cm behind= 215 plasma second, 172 flattop Fluence estimation: Hα light integration He beam edge diagnostic Temperature excursion with heat flux model I E Top View 0.5 – 1 x D/m 2 ( to be improved)

No 9 V. Philipps, SEWG Fuel retention, July 2010, Garching IE Limiter after exposure erosion dominated zone deposition dominated zone with layer formation TDS LID TDS Laser desorption

No 10 V. Philipps, SEWG Fuel retention, July 2010, Garching LID-QMS Spectra for Graphite QMS-Delta-Signal / V QMS Signal / V m/q / amu/e before laser pulse after laser pulse desorption spectrum = after – before H2 D2 C CH4 CD4 CO CO2 DN2 HD H2O U in V number of atoms via calibration factor ALT 2/29 tile: – inside TEXTOR QMS thick deposition D/m H/m D/m H/m D/m H/m D/m H/m D/m H/m 2

No 11 V. Philipps, SEWG Fuel retention, July 2010, Garching Heating of a Quartz tube form outside Lock system to introduce samples without breaking vacuum Vacuum < mbar Background heating measurement before and after TDS TDS measurements

No 12 V. Philipps, SEWG Fuel retention, July 2010, Garching R= similar shots Spot pyrometer on the graphite samples 2D IR camera in parallel Light reflection

No 13 V. Philipps, SEWG Fuel retention, July 2010, Garching TDS on JET W samples 1: μm 2: 10-15μm Perp fiber 1.3 K/sec Storage of samples in vacuum TDS 3 weeks after exposure μm μm 1: D/m2 2: D/m2

No 14 V. Philipps, SEWG Fuel retention, July 2010, Garching Present data, W on JET CFC D/m 2 Previous data fine grain graphite EK D/m 2 For comparison : retention in C ( EK98, JET Dunlop CFC ) A.Kreter et al 2x D/m2 Retention on upper edge

No 15 V. Philipps, SEWG Fuel retention, July 2010, Garching Comparison W bulk and W JET layer: 6-8 times more D in W JET layers Different exposure temperatures (about 150 C) Different waiting times until TDS Different surface structure

No 16 V. Philipps, SEWG Fuel retention, July 2010, Garching

No 17 V. Philipps, SEWG Fuel retention, July 2010, Garching