A metallographic and fractographic study of outside-in cracking caused by power ramp tests

Shimada, Sachio; Etoh, E.; Hayashi, Hiroshi; Tukuta, Y.

doi:10.1016/j.jnucmat.2004.01.022

Cited by 70 publications

(25 citation statements)

References 7 publications

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“…Outside-in type cracking in high burnup BWR fuels arising in power ramp tests is attributed to hydride embrittlement in the outermost region of the cladding [1]. One possible explanation is that, during power transients, hydrogen that had accumulated in the region of the Zr liner diffused toward tube's cooler outside region, resulting in radial hydride growth under the stress orientation mechanism.…”

Section: Thermal Diffusion Of Hydrogen In Power Ramp Conditionmentioning

confidence: 99%

“…To simulate an actual power ramp test [1], a model calculation was conducted using the following conditions: BWR fuel rod of 8 Â 8 size (0.86 mm cladding thickness, 0.09 mm Zr liner thickness); initial average hydrogen content of 3 at.% (335 ppm); a preconditioning power level of 200 W/cm for 15 h; terminal power at ramp test of 428 W/cm; circumferential stress at ramp test of 300 MPa. Unfortunately, since the present model cannot reproduce exactly an initial distribution of hydride in the cladding, a similar distribution was made by trial and error.…”

Section: Thermal Diffusion Of Hydrogen In Power Ramp Conditionmentioning

confidence: 99%

“…Hydride-related embrittlement of fuel cladding and structural material made of Zr alloys is one of the most important issues limiting light water reactor fuel performance at high burnup; for example, the outside-in type cracking in high burnup BWR cladding arising at power ramp tests [1]. When considering hydride behavior in Zr alloys, the terminal solid solubility (TSS) of hydrogen for hydride dissolution (TSSD) and hydride precipitation (TSSP) is a prime factor, and for further detailed quantitative analyses, a mechanistic and microscopic model containing TSS data is needed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The terminal solid solubility of hydrogen in irradiated Zircaloy-2 and microscopic modeling of hydride behavior

Une

Ishimoto

Etoh

et al. 2009

Journal of Nuclear Materials

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Section: Thermal Diffusion Of Hydrogen In Power Ramp Conditionmentioning

confidence: 99%

Section: Thermal Diffusion Of Hydrogen In Power Ramp Conditionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The terminal solid solubility of hydrogen in irradiated Zircaloy-2 and microscopic modeling of hydride behavior

Une

Ishimoto

Etoh

et al. 2009

Journal of Nuclear Materials

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“…1) Water quality changes in reactor coolant systems, such as hydrogen addition or noble metal injection to the coolant as a remedy for stress corrosion cracking of reactor component materials, are thought to also accelerate the hydrogen pickup of zirconium alloy. The terminal solid solubility of hydrogen in zirconium at room temperature is low, 2) and zirconium hydride may precipitate, degrading the mechanical properties of the fuel bundle component materials.…”

Section: Introductionmentioning

confidence: 99%

Interpretation of Acoustic Parameters Obtained by EMAR Measurement for Non-destructive Hydrogen Concentration Measurement in Zr Alloy

Nakatsuka¹,

Uchida²,

Miyazaki

et al. 2007

J. Nucl. Sci. Technol.

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An obvious quantitative relation between hydrogen concentrations in zirconium alloy and acoustic anisotropy parameters obtained by the electromagnetic acoustic resonance (EMAR) method was reported. To elucidate the mechanism, the acoustic parameters were calculated based on the elastic theory and the equation of motion. The acoustic parameters obtained by the EMAR method were interpreted quantitatively using the anisotropic elastic constants of the specimen, and values calculated from texture data for non-hydrogen charged specimens showed good agreement with those obtained by the EMAR method. Calculated temperature dependence of the acoustic anisotropy for the non-hydrogen charged specimen also agreed well with that by the EMAR method.The consistencies demonstrated that the absolute values of the acoustic parameters for non-hydrogen charged specimens can be calculated from both the texture data of (0002) pole figure and the elastic constants of the specimen. Hydrogen addition up to approximately 650 ppm was found not to change the original (0002) pole figure and, correspondingly, no hydrogen concentration dependence of the acoustic parameters was obtained from the calculation. These results implied that the zirconium hydride itself played an important role for the change in the acoustic parameters of the hydrogen charged specimens, and the importance of obtaining the information on the elastic constants of the zirconium hydride was pointed out.

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“…1) Because of the low terminal solid solubility of hydrogen in zirconium 2) and the low ductility of precipitated zirconium hydride, 3) the accumulated hydride tends to degrade the mechanical properties of the zirconium alloy in a fuel bundle. Thus, knowledge of the amount of the hydride precipitated in the zirconium alloy is presumably important for the evaluation of the integrity of nuclear fuel assembly components made of zirconium alloys.…”

Section: Introductionmentioning

confidence: 99%

Annealing Study on Neutron Irradiation Effects in Resonance Frequencies of Zircaloy Plates by EMAR Method

Nakatsuka¹,

Uchida²,

Miyazaki

et al. 2007

Journal of Nuclear Science and Technology

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To develop the nondestructive hydrogen concentration measurement method for the irradiated zirconium alloy, the effect of neutron irradiation damage on acoustic properties obtained by the electromagnetic acoustic resonance (EMAR) method was investigated through annealing tests. It is confirmed that the recovery of irradiation damage begins at a lower annealing temperature than that in unirradiated coldworked materials. Unirradiated recrystallization-annealed materials did not show any change in acoustic properties or hardness during the additional RX annealing at 580 C, whereas the acoustic anisotropy (Áf) of the as-cold-worked unirradiated specimen was significantly increased. Four-cycle irradiation clearly decreased the shear wave velocity of the specimen by 1% compared to the RX-annealed specimen. In comparison with the wave velocity change, the acoustic parameters defined in this study are found to be less sensitive to irradiation damage. From the annealing study of the as-irradiated specimens to the RX condition, it is concluded that the absolute value of (Áf) increases by 0.1% and the frequency ratio (fl/fr) by about 0.006 as a result of the damage induced by the four-cycle irradiation in BWRs. These values are applicable to the relationships between the acoustic parameters and hydrogen concentrations of unirradiated materials as the correction factors to compensate the effects of irradiation damage.

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A metallographic and fractographic study of outside-in cracking caused by power ramp tests

Cited by 70 publications

References 7 publications

The terminal solid solubility of hydrogen in irradiated Zircaloy-2 and microscopic modeling of hydride behavior

The terminal solid solubility of hydrogen in irradiated Zircaloy-2 and microscopic modeling of hydride behavior

Interpretation of Acoustic Parameters Obtained by EMAR Measurement for Non-destructive Hydrogen Concentration Measurement in Zr Alloy

Annealing Study on Neutron Irradiation Effects in Resonance Frequencies of Zircaloy Plates by EMAR Method

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