M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
In-situ neutron radiography investigations of the hydrogen absorption of zirconium
alloys during steam oxidation
M. van den Berg, M. GroßeInstitute for Materials Research 1
Karlsruhe Institute of Technology, Germany
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ContentIntroductionHydrogen determination by means of neutron radiography
•Experimental setup – INRRO
•Data processing
Hydrogen uptake by Zirconium alloys/Results•Temperature dependence of Hydrogen total neutron cross section in ZrH2
•In-situ steam oxidation experiment in Zry-4
•Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Summary and Conclusions
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ContentIntroductionHydrogen determination by means of neutron radiography
•Experimental setup – INRRO
•Data processing
Hydrogen uptake by zirconium alloys/Results•Temperature dependence of Hydrogen total neutron cross section in ZrH2
•In-situ steam oxidation experiment in Zry-4
•Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Summary and Conclusions
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Context
Possible dangers and accidents in nuclear fission reactors
Loss Of Coolant Accidents (LOCA)
Re-flooding the reactor core with water or steam
Severe Fuel rod Damage (SFD)
Rod temperature rises quickly, Core dries out
Introduction
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Reaction between hot nuclear fuel rod cladding and steam:
2 H2O + Zr + 2VO(2+) + 4e- → ZrO2 + 4p+ 4e-
4p+ + 4e- → 2·x H2↑ + 4(1-x) Habs
change of the time dependence of H release
embrittlement of the cladding material
risk of hydrogen detonation
Introduction
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Currently the following two topics are being investigated
•The hydrogen absorption of zirconium alloys during steam oxidation
•The temperature dependence of Σ of hydrogen solute in β-zirconium
Introduction
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ContentIntroductionHydrogen determination by means of neutron radiography
•Experimental setup – INRRO
•Data processing
Hydrogen uptake by zirconium alloys/Results•Temperature dependence of Hydrogen total neutron cross section in ZrH2
•In-situ steam oxidation experiment in Zry-4
•Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Summary and Conclusions
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Hydrogen determination by means of neutron radiography
X-ray radiography neutron radiography
Objects
with small total cross section have a high transmission (bright),
with high total cross section have a low transmission (dark)
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Hydrogen determination by means of neutron radiography
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.00
1
2
3
4
5
6 CCD camera without filter CCD camera with Be-filter Image Plate
Σ [c
m-1]
H/Zr ratio
Dependence of total macroscopic neutron cross section on hydrogen concentration and on oxide layer thickness
0 100 200 300 400 500 600
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
Σ tota
l [cm
-1]
oxide layer thickness [µm]
samples wereoxidized in Ar/O2
samples wereannealed in Ar/H2
Calibration
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
In
I
In-situ NeutronenRadiographieReaktionsOfen
Air lock
beam windowsample
Nb resistance
heater
H2O cooling
neutronbeam
neutron camera system
Gas
and
ste
am
flow
con
trolle
r Off-gas
Hydrogen determination by means of neutron radiography
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Hydrogen determination by means of neutron radiography
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Hydrogen determination by means of neutron radiography
xeIIT Σ−==0 x
T)ln(−=Σ
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ContentIntroductionHydrogen determination by means of neutron radiography
•Experimental setup – INRRO
•Data processing
Hydrogen uptake by Zirconium alloys/Results•Temperature dependence of Hydrogen total neutron cross section in ZrH2
•In-situ steam oxidation experiment in Zry-4
•Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Summary and Conclusions
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Temperature dependence of Hydrogen total neutron cross section in ZrH2
Hydrogen uptake by Zirconium alloys/Results
Hydrogen absorption at 1000°C with 2,4 and 8 g/h
Sigma
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
0 20 40 60 80 100 120 140
Measurement (20s/frame)
Sig
ma
Sigma
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
In-situ steam oxidation experiment in Zircaloy 4
Hydrogen uptake by Zirconium alloys/Results
Steam oxidation in Zry-4 at 1000°C
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Hydrogen uptake by Zirconium alloys/Results
Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Hydrogen diffusion at 900°C Hydrogen diffusion at 550°C
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ContentIntroductionHydrogen determination by means of neutron radiography
•Experimental setup – INRRO
•Data processing
Hydrogen uptake by Zirconium alloys/Results•Temperature dependence of Hydrogen total neutron cross section in ZrH2
•Oxygen absorption by pre-oxidized Zry-4 alloys
•Diffusion of hydrogen in an oxygen coated Zry-4 cylinder
Summary and Conclusions
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
Summary and ConclusionsNeutron radiography is a powerful tool for a fast, non-destructive, and
quantitative determination of the hydrogen content in zirconium alloys with high lateral resolution (< 30 µm). In-situ investigations are possible.
The hydrogen uptake at the beginning of steam oxidation is very fast. After about 600s the maximal hydrogen concentrations seems to bereached.
M. van den Berg, In-situ Experimente in der material forschung, Karlsruhe, 19. Jan. 2010
ThanksThanks
KIT IMF 1:KIT IMF 1:In particular In particular M. GroM. Großße and M. Steinbre and M. Steinbrüückck
PSI:PSI:The The NNeutron eutron IImaging and maging and AActivation ctivation GGroup roup NIAGNIAG in particular in particular E. Lehmann and A. Kaestner E. Lehmann and A. Kaestner
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