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RESULTS
The major result is a laboratory equipped by performance techniques of investigation and analysis, capable to provide data of good quality on nuclear fuel and materials irradiated in the Cernavoda NPP CANDU reactors and in the dedicated experiments such as LOCA (Loss of Coolant Accident), RIA (Reactivity Insertion Accident) and Power Ramping performed in the SCN TRIGA material testing reactor.
The Optical Microscopy is one of the most important post-irradiation examination techniques to provide detailed information on microstructural features of the nuclear reactor fuel. It allows to observe the fuel and cladding structure, pellet-cladding gap, outer and inner oxide layer thickness and cladding thickness. An image analyzer is available to evaluate pore size and UO2 grain size. The features and orientation of the hydride precipitates in the cladding can be observed.
Leica TELATOM 4 Remote Controlled lnverted Widefield Metallographic Microscope for Radioactive Materials
Basic Parameters:
- Resolution: 0,3 µm for working distance of 1,6 m;
- Magnification range: from 8x to 2500x;
- Motorized sextuple nosepiece;
- Plan EPI objectives: 2,5x/0,075; 5x/0,10; 10x/0,20 IK; 20x/0,40 IK; 50x/0,80 IK; 100x/0,95 IK;
- Plan Apo objective: 1x/0,03;
- Motorized scanning stage:
- Stepping motors for x-y movements (range 40 x 40 mm) and focus-movement. The position is indicated in 1µm steps;
- Stage rotation is 200°, driven by a servo system, with digital position indication in 0.1° steps;
- Motorized superstage: 360° rotation, with digital position indication in 0.5° steps;
- Maximum diameter of specimen: 60 mm;
- Binocular viewing tube with a pair of widefield eyepieces WP 10x;
- Automatic 35 mm camera and the large format camera 9 x 12 cm;
- Motorized magnification changer: 0.8x - 1x - 1.25x - 2.5x;
- Filter insert with turret with green interference filter, UV barrier filter and 3 neutral filters (0.2%, 1.6%, 12.5%);
- Fully automatic system for image acquisition and analysis, including:
- X,Y, Z motor control board and autofocus control board;
- Colour digital camera;
- Station PC, monitor LCD;
- Software for image analysis to investigate the microstructural features of the metallic and ceramic materials. Measurement of grain size according to ASTM standards.
Examination Techniques:
- Brightfield;
- Oblique illumination;
- Polarized light with +/- 90° rotatable polarizer and analyser;
- NORMARSKI differential interference contrast (DIC).
Applications:
- Grain size and distribution;
- Phase segregation and identification;
- Inclusion content;
- Porosity measurements;
- Corrosion susceptibility (oxide layer thickness and cladding thickness);
- Features and orientation of the hydride precipitates in the cladding;
- Pellet-cladding gap;
- Failure analysis;
- Integrity evaluation of the welds, brazes etc.
The Scanning Electron Microscopy (SEM) is best suited for examination of fracture surfaces for both fuel and cladding and structural materials. For cladding and structural materials the fracture surface is normally created by mechanical testing. A sample of irradiated ceramic fuel can be fractured to be examined by SEM. The fracture will normally contain significant intergranular areas which enable to study the grain boundary porosity and fission product precipitates. The structure of the zirconium oxide layer and the features of the zirconium hydride can be also examined by SEM.
TESCAN MIRA II LMU CS Schottky Field Emission Variable Pressure Scanning Electron Microscope
Basic Parameters:
- Resolution in high vacuum mode with SE detector:
- 1,2 nm at 30 kV
- 1,5 nm at 15 kV
- 2,5 nm at 3 kV
- 4,5 nm at 1 kV
- Resolution in low vacuum mode with SE detector:
- 1,5 nm at 30 kV
- 3,0 nm at 3 kV
- Resolution in high/low vacuum mode with BSE detector:
- Chamber working vacuum in high vacuum mode: < 1 x 10-3 Pa
- Chamber working vacuum in low vacuum mode: 7 ÷ 150 Pa
- Magnification: 4x to 1 000 000x
- Accelerating voltage: 200 V to 30 kV in 10 V steps
- Electron gun: High brightness Schottky emitter
- Probe current: 2 pA to 100 nA
- Specimen chamber:
- Number of ports: 11 ports with optimized geometry for EDS, WDS, EBSD
- Chamber suspension: pneumatic with compressed air
- Internal diameter: 230 mm
- Door width: 148 mm
- Specimen stage:
- Type: compucentric
- 5 axis fully motorized stage:
- X = 80 mm (40 mm to +40 mm), Y = 60 mm (30 mm to +30 mm), Z = 47 mm
- Rotation: 360° continuous
- Tilt: -750 to +500 from working distance of 15 mm
- Specimen height: maximum 60 mm
- Detectors:
- SE detector (SED) equipped by an YAG (Yttrium Aluminium Garnet) scintillation crystal
- Retractable BSE detector (BSED) equipped by an YAG (Yttrium Aluminium Garnet) scintillation crystal with high sensitivity and high atomic number resolution (0,1)
- Fully automatic system for image acquisition and analysis, including:
- Station PC, monitor LCD, colour printer;
- Software for image acquisition, archiving, processing and analysis.
Applications:
- Topographic analysis: the surface features of a material, its texture; direct relation between these features and material properties (hardness etc.);
- Morphologic analysis: the shape and size of the particles making up the material; direct relation between these structures and material properties (ductility, strength etc.);
- Identification and evaluation of microstructure on sample surface, fission gas porosity at grain boundary, fission product precipitates, zirconium oxide layer structure, zirconium hydride features;
- Failure analysis;
- Identification of inclusions or contaminants;
- Non-metallic and non-conductive materials can be examined without coating or sample preparation.
DYNA DM1007 Milling Machine with Numerical Process Control Systemfor Preparation of Radioactive Samples
Basic Parameters:
- X, Y, Z axis travel: 250 x 175 x 250 mm;
- Table size: 450 x 180 mm;
- Table working area: 250 x 175 mm;
- Maximum table load: 60 kg;
- Maximum X, Y, Z axis travel speed: 5/5/5 m/min.;
- Cutting feed rate: 0 ÷ 5000 mm/min.;
- Manual feed rate: 0 ÷ 5000 mm/min.;
- Spindle rotate speed: 60 ÷ 10000 rpm;
- Spindle nose to table distance: 95 ÷ 350 mm;
- Spindle taper: ISO 30;
- Number of tools: 6;
- Automatic tool changer;
- Tool holder: tip BT-30;
- Maximal tool diameter: 50 mm;
- Maximal tool length: 150 mm;
- Maximal tool weight: 2 kg;
- Control: Dyna PCIII;
- Simultaneous X, Y, Z axis control;
- Positioning precision: 0,001 mm;
- Feed rate range: 0,001 mm;
- Software SurfCAM 2 Axis SE.
Applications:
- Preparation of radioactive samples for mechanical testings: zirconium alloys samples, stainless steel samples etc., from CANDU reactor pressure tube, CANDU fuel cladding and other component parts of nuclear reactor;
- Precise cutting of radioactive samples from metallic and ceramic materials.
Last update: 14.09.2009
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