Skip to main content Accessibility help
×
Home

Determination of residual stresses around blisters in Zr-2.5%Nb pressure tubes

  • Javier R. Santisteban (a1), Axel Steuwer (a2), Gladys Domizzi (a3) and Matthew J. Peel (a4)

Abstract

We have used synchrotron X-ray diffraction experiments to measure the strain field introduced by a hydride blister grown on a section of a pressure tube from a CANDU nuclear reactor. After charging the tube section with a homogeneous hydrogen concentration of 300 wt ppm, the blister was produced by creating a small cold spot on its surface (∼200 °C), while the bulk was kept at a temperature of 338 °C over a period of 1008 h. The blister studied here is ellipsoidal in shape, with its long axis along the tube axial direction. The experiments were performed on the wiggler beam line ID15 at the European Synchrotron Radiation Facility (ESRF) using a polychromatic beam of high-energy X-rays (60 to 300 keV). Unlike conventional X-ray diffraction, in this mode the scattering angle is fixed and the diffracted beam is discriminated on the basis of the photon energy. The results show that the blister is composed by two crystallographic phases (δ-ZrH and α-Zr), with volume fractions varying with position. The maximum stresses appear at the blister-matrix interfaces. Near the tube outer surface, we found large compressive stresses of (−450±90) MPa along the blister long axis, and tensile stresses (+320±90) MPa along the tube hoop direction. The main uncertainty in these stresses results from the uncertainty in the elastic constants of the hydride phase. Large strains and broad peaks were observed for this phase, which were explained by a rather low Young’s modulus (35 GPa) for the hydride. The results are compared with finite element simulations found in the literature.

Copyright

References

Hide All
Barraclough, K. G. and Beevers, C. J. (1970). “Some observations on the phase transformations in zirconium hydrides,” J. Nucl. Mater.JNUMAM 34, 125134.10.1016/0022-3115(70)90112-1
Carr, D. G., Ripley, M. I., Holden, T. M., Brown, D. W., and Vogel, S. C. (2004). “Residual stress measurements in a zircaloy-4 weld by neutron diffraction,” Acta Mater.ACMAFD 52, 40834091.10.1016/j.actamat.2004.05.021
Domizzi, G., Enrique, R. A., Ovejero-García, J., and Buscaglia, G. C. (1996). “Blister growth in zirconium alloys: Experimentation and modeling,” J. Nucl. Mater.JNUMAM 229, 3647.10.1016/0022-3115(95)00204-9
Ells, C. E. (1968). “Hydride precipitates in zirconium alloys (A review),” J. Nucl. Mater.JNUMAM 28, 129151.10.1016/0022-3115(68)90021-4
Field, G. J., Dunn, J. T., and Cheadle, B. A. (1985). “Analysis of the pressure tube failure at pickering NGS ‘A’ unit 2 nuclear systems department,” Can. Metall. Q.CAMQAU 24, 181188.
Kerr, M., Daymond, M. R., Holt, R. A., and Almer, J. D. (2008). “Strain evolution of zirconium hydride embedded in a zircaloy-2 matrix,” J. Nucl. Mater.JNUMAM 380, 7075.10.1016/j.jnucmat.2008.07.004
Perovic, V., Weatherly, G. C., and Simpson, C. J. (1983). “Hydride precipitation in α/β zirconium alloys,” Acta Metall.AMETAR 31, 13811391.10.1016/0001-6160(83)90008-1
Pierron, O. N., Koss, D. A., Motta, A. T., and Chan, K. S. (2003). “The influence of hydride blisters on the fracture of zircaloy-4,” J. Nucl. Mater.JNUMAM 322, 2135.10.1016/S0022-3115(03)00299-X
Puls, M. P., Shi, S. -Q., and Rabier, J. (2005). “Experimental studies of mechanical properties of solid zirconium hydrides,” J. Nucl. Mater.JNUMAM 336, 7380.10.1016/j.jnucmat.2004.08.016
Singh, R. N., Kishore, R., Sinha, T. K., Banerjee, S., and Kashyap, B. P. (2003). “Stress field estimation around a semi-constrained inclusion and its validation by interpreting hydride platelet orientation around a blister in a Zr-2.5Nb alloy,” Mater. Sci. Eng., AMSAPE3 339, 1728.10.1016/S0921-5093(02)00115-6
Steuwer, A., Santisteban, J. R., Preuss, M., Peel, J., Buslaps, T., and Harada, M. (2009). “Evidence of stress-induced hydrogen ordering in zirconium hydrides,” Acta Mater.ACMAFD 57, 145152.10.1016/j.actamat.2008.08.061
Wallace, A. C. (1987). “Numerical analysis of zirconium hydride blisters in CANDU reactor pressure tubes,” 9th International Conference on Structural Mechanics in Reactor Technology, pp. 8792.
Zuzek, J., Abriata, P., San-Martin, A., and Manchester, F. D. (1990). “The H-Zr (hydrogen-zirconium) system,” Bull. Alloy Phase DiagramsBAPDDW 11, 385395.10.1007/BF02843318

Keywords

Determination of residual stresses around blisters in Zr-2.5%Nb pressure tubes

  • Javier R. Santisteban (a1), Axel Steuwer (a2), Gladys Domizzi (a3) and Matthew J. Peel (a4)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.