Post on 25-Mar-2022
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Coated Particle Fuel Characterization Labfor the
Advanced Gas Reactor Fuel Developmentand Qualification Program
John HunnANS/GLOBAL 200318 November, 2003
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Purpose of Presentation
• Introduction to ORNL’s new coated particle fuelcharacterization effort
• Description of current capabilities• Demonstration of some of the measurements
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Fuel Kernel(UCO, UO2)
Coated Particle
Outer Pyrolytic Carbon
Silicon Carbide
Inner Pyrolytic Carbon
Porous Carbon Buffer
TRISO-Coated Particle Fuel
•• Kernels to be used atKernels to be used atORNL in AGR ProgramORNL in AGR Program
-- 500 500 mmm depleted UO2m depleted UO2
-- 350 350 mmm depleted UO2m depleted UO2
-- 350 350 mmm natural UCOm natural UCO
-- 350 350 mmm LE UCOm LE UCO
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Properties to Measure
KERNELSSize
ShapeDensity
Composition
BUFFERThicknessUniformity
DensityPorosityIPyC
ThicknessUniformity
DensityPorosity
MicrostructurePermeabilityAnisotropy
SiCThicknessUniformity
DensityGrain Size
MicrostructureFailure fraction
OPyCThicknessUniformity
DensityPorosity
MicrostructureAnisotropy
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
MaterialographyBackPot
Rotary polisher in Hood
HotPress
Mount
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Microscopy
AnalyticScope
StereoScope
Computer-controlled stage for automatic imaging
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
mic
rons
degrees
Kernel & Layer boundaries as distance from center
Kernel
Buffer
OPyCSiCIPyC
Measurement Buffer/IPyC/SiC/OPyC thickness
Technique Optical inspection of polished cross sections
Equipment
Hot mount pressRotoSystem for grinding and polishingCold mount vacuum impregnatorOptical microscope with reflected and transmitted light,digital camera, goniometer stage
Method
Using clear acrylic, mount 99 coated particles in a gridFine grind with 9 µm Allegro until kernels exposedBackpot with fluorescent epoxy to immobilize kernelsFine grind with 9 µm Allegro to near mid-planePolish with 3 µm Dac then 1 µm DacImage at 12.5x polished cross-section with reflectedbright field illumination and use transmitted light toilluminate mid-planeCapture 99 images using grid scanExtract info on coating thicknesses with Mat Lab
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Micron-resolution x-ray imaging test results1-2 mm resolution
Radiograph of 300mm diameter ZrO2 TRISO
~5 mm resolution
Imaging of this quality would beadequate for non-destructivemeasurement of coating thicknessand identifying coating defects
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Sphericity1.03±.011.01-1.08
Diameter509±4 µm502-522 µm
Sieved ZrO2 132 kernels measured
Measurement Kernel diameter and sphericity - Option 1 Kernel diameter and sphericity - Option 2
Technique Optical inspection of a random sample Measure each kernel with laser obscuration
EquipmentOptical microscope with transmitted light, digital camera,goniometer stage
Particle size analyzer with pneumatic particle transportsystem - under development
Method
Pour single layer of kernels in tray and cover with glassShadow image at 5x with transmitted lightCapture images using frame scanExtract radius R(N) for N= 1-360°Report mean, s.d., min, max, sphericity for each kernelReport mean, s.d., min, max of individual meansReport mean, s.d., min, max of sphericities
Suck up kernels into a 1.5x diameter ID tubePass kernels through a laser slitMeasure amount of light blocked by each kernelDisentrain kernels from air flow in a cyclone separator
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Measurement Kernel density
Technique Gas pycnometry and Hg porosimetry
Equipment
He pycnometerAnalytical balanceHg porosimeter
MethodRun standard measurement using pycnometerNeed to check if kernel porosity is significant
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
MercuryPorosimeterIn Hood
Measurement Buffer density
TechniqueMeasure buffer coated kernel and subtract out contribution ofkernel
EquipmentHg porosimeterParticle counter
Method
Count representative sample of kernelsMeasure weight and volume of kernelsCount representative sample of buffer coated kernelsMeasure weight and volume of buffer coated kernelsDensity of buffer = Diff. in av. weight / Diff. in av. Volume
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
SiC PyC
Measurement SiC density OPyC density
Technique Measure float density and check porosity Same
Equipment
Liquid gradient density columnTemperature controlled water bathPeristaltic pump with fill systemCalibrated reference floatsHg porosimeter Same
MethodBuild 3.1- 3.3 g/cc column with Bromoform andMethylene iodide
Build 1.7-2.1 g/cc column with Tetrachloroethyleneand Dibromoethylene
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Scanned at 4800 dpi
Measurement IPyC permeability SiC Defects
Technique U leaching by HCl Mercury intrusion
EquipmentHCl ready tube furnace20 µm resolution x-ray system
Muffle furnaceHg porosimeter20 µm resolution x-ray system
Method
Heat particles in HClMount particles in grid and seal with Kapton tapeX-ray particles and look for U in buffer
Burn back to SiC in air at 750-850°CExpose particles to Hg under pressureMount particles in grid and seal with Kapton tapeX-ray particles and look for Hg inside of SiC
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Measurement SiC grain size SiC grain size
Technique Relief polishing Wet chemical etch
Equipment Vibratory polisher
GlasswareHotplate/StirrerVoltage supply
Method
Prepare polished cross sections as for coating thicknessmeasurementRelief polish with .05 µm silicaImage with optical microscope
Electrolytic oxidation in potassium dichromate andphosphoramide solutionObserve different grain orientations by colorHF etch to remove oxideElectrolytic grain boundary etch in oxalic acidObserve grain size
Before relief polish After relief polish
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
New Ellipsometry Method for Measuring theCrystallographic Anisotropy of Pyrocarbon
Layer to Replace OPTAF
• More complete measurement of anisotropy• Higher resolution• Less sensitive to experimental error from specular
reflection• Able to measure anisotropy over the entire cross-
section
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Mueller-Stokes Description of Polarization
˜̃
˜˜˜
¯
ˆ
ÁÁÁÁÁ
Ë
Ê
-
-
-=
˜̃
˜˜˜
¯
ˆ
ÁÁÁÁÁ
Ë
Ê
=-
lcrc
oo
II
II
II
I
V
U
Q
I
4545
900S
˙˙˙˙
˚
˘
ÍÍÍÍ
Î
È
-
--=
443424
34332313
24232212
1312
0
01
mmm
mmmm
mmmm
mm
normalM
Stokes Vector: Mueller Matrix:
OPTAF only measured m12 => incomplete measurement
12)/(1
)/(1m
RR
RR
RR
RRN
sp
sp
ps
ps -=+
-=
+
-=
†
OPTAF =Rs
Rp
=1+ N1- N
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
IntensityDiattn |N|
(0.00 to 0.04)Retard |_| (0 to 0.1)
Circ. Diattn (0 to 0.05)
Preliminary results with coated particles
(0.00 to 0.08) (0.00 to 0.08) (0.00 to 0.05)
C3H6
C2H2:C3H6 ~1:1
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Intensity (0 – 1)
Beta (0.98 – 0.95)
Circ. Diattn. (0.02 - -0.02)
Retardation (-0.25 - -0.50)
Diattn. (0.40 – 0.65)
Princ. Angle (170° – 180°)
Highly Oriented Pyrolitic Graphite (10/03/03)