Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지

DHC Characteristics of M11 Pressure Tube in Wolsong Unit 1

  • Published : 2000.02.01
Download PDF
⟨ Previous Next ⟩

Abstract

Delayed hydride cracking (DHC) velocity and threshold stress intensity factor for DHC ($K_{IH}$) tests in the radial direction on M11 pressure tube material in Wolsong unit 1 were carried out following the Atomic Energy Canada Limited (AECL) standard test procedure in order to identify the effect of undercooling on DHCV and to acquire the $K_{IH}$ data. The results showed that $K_{IH}$ 's were 8.8$\pm$0.8 MPa√m in the back offcut and 11.4$\pm$0.7 MPa√m in the front offcut. The fact that $K_{IH}$ in the front offcut is about 20% higher than that in the back offcut is attributed to the microstructural difference between the materials of the front and back ends. $K_{IH}$ 's in M11 pressure tube appeared to be higher than the values from the tubes made of double melted ingot reported earlier. This can be interpreted by the fact that very small amounts of Chlorine (Cl) and Phosphorus (P) are contained in the ingot and that the content of the harmful elements in the M11 pressure tube is equivalent to that made of a quadruple melting process. DHC velocities at 25$0^{\circ}C$ in the front offcut in the radial direction are measured to be 5~8$\times$10$^{-8}$ m/s. The results show that the prior thermal history change the DHC velocity significantly. This effect was confirmed by the experiment of undercooling prior to the DHC tests.DHC tests.

Keywords

References

  1. C. E. Coleman and J. F. R. Ambler, 'Susceptibility of Zirconium Alloys to Delayed Hydride Cracking' Zirconium in the nuclear industry, ASTM STP 633, pp. 589-607, (1977)
  2. S. Sagat, J. F. R. Ambler, and C. E. Coleman, 'Application of Acoustic Emission to Hydride Cracking' , AECL report, AECL-9258, (1986)
  3. C. E. Coleman, B. A. Cheadle, C. D. Cann, and J. R. Theaker, 'Development of Pressure Tubes with Service Life Greater than 30 Years', Zirconium in the Nuclear Industry, Eleventh International Symposium, ASTM STP 1295, pp. 884-898, (1996)
  4. S. S. Kim, S. C. Kwon, and Y. S. Kim, 'The Effects of Texture Variation on the DHC Behavior in Zr-2.5%Nb Plates' , J. Nucl. Mater. Vol. 273, pp. 52-59, (1999) https://doi.org/10.1016/S0022-3115(99)00017-3
  5. E. F. Ibrahim, and A. B. Cheadle, 'Development of Zirconium Alloys for Pressure Tube in CANDU Reactors' , Canadian Metallurgical Quarterly, Vol. 24, pp. 273-281, (1985)
  6. I. Aitchison and P. H. Davies, 'Role of Microsegragation in Fracture of Cold-Worked Zr-2.5%Nb Pressure Tubes' , J. Nucl. Mater. Vol. 203, pp. 206-220, (199) https://doi.org/10.1016/0022-3115(93)90377-B
  7. C. E. Coleman, 'Effect of Texture on Hydride Reorientation and Delayed and Delayed Hydrogen Cracking in Cold worked Zr2.5%Nb', Zirconium in the Nuclear Industry, Fifth Conference, ASTM STP 754, pp. 393-411, (1982)
  8. H. Huang, and W. J. Mills, 'Delayed Hydride Cracking Behavior for Zircaloy-2 Tubing' Metal. Transactions A 22A, pp. 2149-2060, (1991). https://doi.org/10.1007/BF02669872
  9. W. J. Mills, and F. H. Huang, 'Delayed Hydride Cracking Behavior for Zircaloy-2 Plate', Eng. Frac. Mech. 39, pp. 241-257, (1991) https://doi.org/10.1016/0013-7944(91)90040-8
  10. S. S. Kim, K. N. Choo, S. B. Ahn, S. C. Kwon, and Y. S. Kim, 'KIH in the Radial Textured pressure tube', Proceedings of the Korean Nuclear Society Spring Meeting, Seoul, Korea, May, pp. 93-98, (1998)
  11. S. S. Kim, K. N. Choo, S. B. Ahn, S. C. Kwon, and Y. S. Kim, The Texture Dependence of KIH in the Radial Direction in Zr-2.5%Nb pressure Tube Materials' , Proceedings of the Korean Nuclear Society Spring Meeting, Pohang, Korea, May, p 225, (1999) (paper number 243 on Proceeding of CD-ROM)
  12. S. Sagat, C. E. Coleman, M. Griffiths, and B. J. S. Wilkins, 'The Effect of Fluence and Irradiation Temperature on Delayed Hydride Cracking in Zr-2.5%Nb', Zirconium in the Nuclear Industry, Tenth International Symposium, ASTM STP 1245, pp. 35-61, (1994) https://doi.org/10.1520/STP15183S