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Delayed hydride cracking of Zr-2.5%Nb pressure tube material due to partially constrained precipitates

Murty, T. Narayana; Singh, R. N. LU and Ståhle, P. LU (2019) In Journal of Nuclear Materials 513. p.129-142
Abstract

Formation of partially constrained precipitates such as hydride blisters and oxide nodules have been reported on surfaces of Zr-alloy components of pressurised heavy water reactors and is associated with a large increase in volume. Such a change in volume imposes large stresses in the material surrounding the precipitate and may facilitate stable crack growth through delayed hydride cracking. In this work, the stress field of the partially constrained precipitates with different depth and aspect ratio has been computed using a finite element method. The computed stress field is used to predict the region in the matrix in which radial hydride is likely to form and fracture, by taking into consideration grain-size, texture and multi-axial... (More)

Formation of partially constrained precipitates such as hydride blisters and oxide nodules have been reported on surfaces of Zr-alloy components of pressurised heavy water reactors and is associated with a large increase in volume. Such a change in volume imposes large stresses in the material surrounding the precipitate and may facilitate stable crack growth through delayed hydride cracking. In this work, the stress field of the partially constrained precipitates with different depth and aspect ratio has been computed using a finite element method. The computed stress field is used to predict the region in the matrix in which radial hydride is likely to form and fracture, by taking into consideration grain-size, texture and multi-axial state of stress. For a hypothetical crack just below the precipitate, stress intensity factors are estimated using material properties for both unirradiated and irradiated pressure tube materials. The results are compared with the threshold stress intensity factors required for crack growth due to delayed hydride cracking.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Delayed hydride cracking, Finite element method, Hydride blister, Oxide nodule, Stress field, Zr-2.5%Nb alloy
in
Journal of Nuclear Materials
volume
513
pages
14 pages
publisher
Elsevier
external identifiers
  • scopus:85056153392
ISSN
0022-3115
DOI
10.1016/j.jnucmat.2018.10.040
language
English
LU publication?
yes
id
0b9eda04-3082-4642-a5c6-d5cf84df00a3
date added to LUP
2018-11-21 12:21:44
date last changed
2019-02-20 11:36:56
@article{0b9eda04-3082-4642-a5c6-d5cf84df00a3,
  abstract     = {<p>Formation of partially constrained precipitates such as hydride blisters and oxide nodules have been reported on surfaces of Zr-alloy components of pressurised heavy water reactors and is associated with a large increase in volume. Such a change in volume imposes large stresses in the material surrounding the precipitate and may facilitate stable crack growth through delayed hydride cracking. In this work, the stress field of the partially constrained precipitates with different depth and aspect ratio has been computed using a finite element method. The computed stress field is used to predict the region in the matrix in which radial hydride is likely to form and fracture, by taking into consideration grain-size, texture and multi-axial state of stress. For a hypothetical crack just below the precipitate, stress intensity factors are estimated using material properties for both unirradiated and irradiated pressure tube materials. The results are compared with the threshold stress intensity factors required for crack growth due to delayed hydride cracking.</p>},
  author       = {Murty, T. Narayana and Singh, R. N. and Ståhle, P.},
  issn         = {0022-3115},
  keyword      = {Delayed hydride cracking,Finite element method,Hydride blister,Oxide nodule,Stress field,Zr-2.5%Nb alloy},
  language     = {eng},
  pages        = {129--142},
  publisher    = {Elsevier},
  series       = {Journal of Nuclear Materials},
  title        = {Delayed hydride cracking of Zr-2.5%Nb pressure tube material due to partially constrained precipitates},
  url          = {http://dx.doi.org/10.1016/j.jnucmat.2018.10.040},
  volume       = {513},
  year         = {2019},
}