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I.Tiseanu, T. Craciunescu and team EURATOM-MEdC, National Institute for Lasers, Plasma and Radiation Physics NILPRP, Bucharest, Romania

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Presentation on theme: "I.Tiseanu, T. Craciunescu and team EURATOM-MEdC, National Institute for Lasers, Plasma and Radiation Physics NILPRP, Bucharest, Romania"— Presentation transcript:

1 I.Tiseanu, T. Craciunescu and team EURATOM-MEdC, National Institute for Lasers, Plasma and Radiation Physics NILPRP, Bucharest, Romania SEWG meeting on Gas balance and fuel retention, July 2010 WP10-PWI /MEdC/BS/PS X-ray micro-tomography studies on CFC samples for porosity network characterization

2 X-RAY MICROTOMOGRAPHY for IFMIF IFMIF HFTM miniaturized specimens and irradiation capsule X-RAY MICROTOMOGRAPHY for JET/ITER ITER- Compressed pebble bed ITER- Welded Steel Pipe with Cu cables ITER like Nb3Sn superconducting wires MgB2 superconducting wires JET reference CFC materials: DMS780 / NB31 NDT inspection of tungsten coating uniformity NDT inspection of CFC / Cu/CuCrZr interfaces INFLPR experience in X-ray microCT for NDT inspection of fusion materials

3 UPGRADED: INFLPR X-RAY nano-CT FACILITY X-ray source – kV –Focus spot < 0.8 m Detector –a-Si flat panel –1210 x 1216 pixels – 0.1 x 0.1 mm 2 Six-axis, high precision manipulator Magnification factor 2000 Resolution benchmark: JIMA Mask (< 0.4 µm) Recently, the X-ray tube has been upgraded to state of the art nanofocus 225 kVp. Gold foil spiral (foil thickness – 5 µm) Micro Resolution Chart for X-ray µm

4 Cross-section through the X-ray microtomography reconstruction and corresponding picture of the irradiation capsule, shown as a CAD model Tomographic cross-section illustrating the gap (lack of thermal contact) between the heater coil and the groove channel. Tungsten wire Heater clad Groove Details are clearly visible as, for example, the heater tube (1 mm diameter) with interior tungsten wire (100 m diameter). X-ray transmission micro- tomography inspection of non- irradiated HFTM capsule (designed and manufactured at FZK) The absolute error of geometrical measurements is sufficient for the assessment of the structural integrity of the irradiation capsule and for the geometry description of the thermal- hydraulic modeling. I. Tiseanu, M. Simon, T. Craciunescu, B. N. Mandache, Volker Heinzel, E. Stratmanns, S. P. Simakov, D. Leichtle. Assessment of the structural integrity of a prototypical instrumented IFMIF high flux test module rig by fully 3D X-ray microtomography. Fusion Engineering and Design, 82, p. 2608–2614, 2007.

5 samples with similar composition and even larger dimensions than the HFTM rig braze by nickel based filler metals used to high temperature base metals as in the HFTM rig. ITHEX experimental facility (FZK) dedicated to thermal-hydraulic investigations concerning mini-channel geometries as applied in IFMIF. several mini-channel test sections are investigated in order to optimize the HFTM helium cooling technology. the mini-channel test sections can be heated by electrical heaters and are instrumented with thermocouples to measure the temperature distribution. Brazing quality assessment 30 mm Brazing structure Thermocouples and heater wires

6 WP10-PWI /MEdC/BS/PS X-ray micro-tomography studies CFC samples for porosity network characterization Participation at DITS project - post mortem analysis by providing high resolution tomography measurements on CFC samples Qualification of the initial porosity of the new CFC ITER reference material NB41 Porosity characterization of tungsten coated CFC samples

7 Determination of Focus spot size by: Micro Resolution Chart for X-ray µm X-ray source target material Four different types of transmission targets have been tested: 1.the standard W target on aluminum window 2.thin W target on beryllium window 3. thin Mo target on beryllium window 4.W target on diamond window. X-ray source target material Four different types of transmission targets have been tested: 1.the standard W target on aluminum window 2.thin W target on beryllium window 3. thin Mo target on beryllium window 4.W target on diamond window. High resolution tomography on CFC materials Optimization of competing CT parameters: -Focus size as small as possible; -X-ray intensity as large as possible; -Energy spectra optimized for best absorption contrast; -High magnification for macroscopic samples. Optimization of competing CT parameters: -Focus size as small as possible; -X-ray intensity as large as possible; -Energy spectra optimized for best absorption contrast; -High magnification for macroscopic samples.

8 Sample size: 10x10 mm 2 Sample size: 4x4 mm 2 Space resolution: 2.5 µm High resolution digital radiography CFC-DMS780 CFC-NB31 Sample size: 2x2x6 mm 3 CFC-NB11

9 CFC NB31: High resolution tomography Sample size: 4x4x4 mm 3 Voxel resolution 2.5 µm 5 µm 14 µm Offset tomography The main challenge is posed by the required micron range of the spatial resolution for rather macroscopic samples.

10 CFC: High resolution tomography Sample size: 4x4x4 mm 3 Voxel resolution: 6 µm CFC-NB31 CFC-DMS780 Morphology differences

11 The detailed 3D morphology representation of statistically relevant volumes of CFC (up to 5x5x5 mm 3 ) materials was used in order to: evaluate the porosity factor; detect possible materials defects like non-homogeneity or high Z dust inclusions. Central panel: an axial cross section on a NB31 CFC sample (voxel resolution 6.6 µm); Left panel: a cut through the main fiber direction along dotted red line; Right panel: the longitudinal cross section along the green solid line. One notes a distinctive feature of NB31- the tiny fibers (needling) somewhat randomly distributed and going perpendicularly to the main fiber direction. Central panel: an axial cross section on a NB31 CFC sample (voxel resolution 6.6 µm); Left panel: a cut through the main fiber direction along dotted red line; Right panel: the longitudinal cross section along the green solid line. One notes a distinctive feature of NB31- the tiny fibers (needling) somewhat randomly distributed and going perpendicularly to the main fiber direction. Morphology of the CFC sample by High resolution tomography

12 CFC NB31: 6 µm/voxel; porosity factor 8.05%CFC DMS780: 6 µm/voxel; porosity factor 9.41% Quantitative evaluation of the CFC porosity factor A procedure for a quantitative evaluation of the sample porosity factor has been introduced and tested. For example for CFC NB31 and CFC DMS780 we obtained porosity factors of 8-10%; in good agreement with the manufacturer specifications

13 Q4-C and Q3-C Two sort of CFC: NB11-92 and NB11-98 Deuterium Inventory in Tore Supra (DITS) post mortem analysis sample cutting plan finger no tile no quarte r partweight in gDeposit typeCfc typeSerial number 543C0.0367erosionN11-92S C0.0347erosionN11-92S C0.0315thickN11-92S C0.033thickN11-92S C0.0387thin, shadowedN11-92S C0.0359thin, shadowedN11-92S C0.0388thin, shadowedN11-92S C0.0341thin, shadowedN11-92S C0.0366erosionN11-98S C0.0403erosionN11-98S524 Cu & porosity Only Cu porosity

14 Deuterium Inventory in Tore Supra (DITS) post mortem analysis Overview experiment Cu brazed CFC NB11: - pattern of Cu filaments along the fiber interspaces Cu brazed CFC NB11: - pattern of Cu filaments along the fiber interspaces Sample size: 2x2x6 mm 3 Sample: CFC NB11 F10 T20 Q3/4 P C CT parameters U=60kV, I=175 µA Target: W Focus spot size: <2.0 µm Voxel resolution: 8.0 µm Overview experiment Overview experiment

15 Deuterium Inventory in Tore Supra (DITS) post mortem analysis Quantitative evaluation of the CFC porosity factor porosity factor ~12.5% Sample: CFC NB11 F10 T20 Q3/4 P C Sample: CFC NB11 F10 T20 Q3/4 P C CT parameters U=80 kV, I=150 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm CT parameters U=80 kV, I=150 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm Morphology: Bright regions: Cu Strong connectivity of the pores along main fiber direction Morphology: Bright regions: Cu Strong connectivity of the pores along main fiber direction

16 Deuterium Inventory in Tore Supra (DITS) post mortem analysis Investigation of the Cu heat sink region Sample: CFC NB11 F5 T9 Q3/4 P C CT parameters U=90kV, I=200 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75µm Morphology: o Strong connectivity of the pores along main fiber direction o Pores coated by Ti o Ti penetrated up to 1.6 mm ?role of Ti in D retention? Morphology: o Strong connectivity of the pores along main fiber direction o Pores coated by Ti o Ti penetrated up to 1.6 mm ?role of Ti in D retention?

17 Deuterium Inventory in Tore Supra (DITS) post mortem analysis Quantitative evaluation of the CFC porosity factor Sample: CFC NB11 F5 T9 Q3/4 P C Sample: CFC NB11 F5 T9 Q3/4 P C CT parameters U=75 kV, I=250 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm CT parameters U=75 kV, I=250 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm Morphology: Strong connectivity of the pores along main fiber direction Morphology: Strong connectivity of the pores along main fiber direction porosity factor ~10%

18 Sample: CFC NB11 F26 T16 Q3/4 P C Sample: CFC NB11 F26 T16 Q3/4 P C CT parameters U=95 kV, I=180 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm CT parameters U=95 kV, I=180 µA Target: Mo Focus spot size: <1.5 µm Voxel resolution: 2.75 µm Morphology: Metallic structures present in the gaps between the main fibers Bright regions: Cu Gray regions: Ti Morphology: Metallic structures present in the gaps between the main fibers Bright regions: Cu Gray regions: Ti Deuterium Inventory in Tore Supra (DITS) post mortem analysis Investigation of the Cu heat sink region

19 Sample: CFC NB11 F26 T16 Q3/4 P C Morphology: Metallic structures advance along main fiber direction interspaces up to 3 mm! Bright regions: Cu Gray regions: Ti CuTi X-ray µbeam fluorescence

20 Computer tomography (µCT) systems are configured to take many views of the object in order to build a 3-D model of its internal structure. For the NDT inspection of miniaturised samples the microtomography analysis is guaranteed for feature recognition down to a few tens of microns. 3-D tomographic reconstructions are obtained by a proprietary highly optimized computer code based on a modified Feldkamp algorithm. The microbeam fluorescence (µXRF) component is a configurable film thickness and composition measuring tool. Main components: optical X-ray beam collimation options, a PIN diode X-ray detector, motorized micrometric x-y-z stage for accurate sample positioning. Tomo-Analytic WP10-PWI /MEdC/PS - X-ray microbeam absorption/fluorescence method as a non-invasive solution for investigation of the erosion of W coatings on graphite/CFC

21 Conclusion and future work High resolution cone beam tomography has been optimized for CFC samples We would like to apply the method: on the new NB41 ITER reference CFC samples; on the tungsten coated CFC samples. We would like to apply the method: on the new NB41 ITER reference CFC samples; on the tungsten coated CFC samples. Current space resolution: ~ 2.5 µm Target ~ 1 µm ! A procedure for a quantitative evaluation of the sample porosity factor has been developed and applied on relevant CFC materials. The potential of multi-energy tomography techniques to improve the quality of the density resolution of the reconstructed images would be assessed. Activities on the microtomography characterization of the Tore Supra CFC samples have been initiated. Main focus: improve the accuracy of the porosity factor measurements! SEWG meeting on Gas balance and fuel retention, July 2010


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