Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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LEAK-BEFORE-BREAK ANALYSIS OF THERMALLY AGED NUCLEAR PIPE UNDER DIFFERENT BENDING MOMENTS

  • LV, XUMING (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing) ;
  • LI, SHILEI (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing) ;
  • ZHANG, HAILONG (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing) ;
  • WANG, YANLI (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing) ;
  • WANG, ZHAOXI (CPI Nuclear Power Institute) ;
  • XUE, FEI (Suzhou Nuclear Power Research Institute) ;
  • WANG, XITAO (State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing)
  • Received : 2015.01.20
  • Accepted : 2015.05.16
  • Published : 2015.12.25
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Abstract

Cast duplex stainless steels are susceptible to thermal aging during long-term service at temperatures ranging from $280^{\circ}C$ to $450^{\circ}C$. To analyze the effect of thermal aging on leak-before-break (LBB) behavior, three-dimensional finite element analysis models were built for circumferentially cracked pipes. Based on the elasticeplastic fracture mechanics theory, the detectable leakage crack length calculation and J-integral stability assessment diagram approach were carried out under different bending moments. The LBB curves and LBB assessment diagrams for unaged and thermally aged pipes were constructed. The results show that the detectable leakage crack length for thermally aged pipes increases with increasing bending moments, whereas the critical crack length decreases. The ligament instability line and critical crack length line for thermally aged pipes move downward and to the left, respectively, and unsafe LBB assessment results will be produced if thermal aging is not considered. If the applied bending moment is increased, the degree of safety decreases in the LBB assessment.

Keywords

References

  1. H. Chung, Aging and life prediction of cast duplex stainless steel components, Int. J. Pres. Ves. Pip. 50 (1992) 179-213. https://doi.org/10.1016/0308-0161(92)90037-G
  2. C. Pareige, S. Novy, S. Saillet, P. Pareige, Study of phase transformation and mechanical properties evolution of duplex stainless steels after long term thermal ageing (> 20years), J. Nucl. Mater. 411 (2011) 90-96. https://doi.org/10.1016/j.jnucmat.2011.01.036
  3. S.L. Li, Y.L. Wang, H.L. Zhang, S.X. Li, K. Zheng, F. Xue, X.T. Wang, Microstructure evolution and impact fracture behaviors of Z3CN20-09M stainless steels after long-term thermal aging, J. Nucl. Mater. 433 (2013) 41-49. https://doi.org/10.1016/j.jnucmat.2012.09.004
  4. S. Bonnet, J. Bourgoin, J. Champredonde, D. Guttmann, M. Guttmann, Relationship between evolution of mechanical properties of various cast duplex stainless steels and metallurgical and aging parameters: outline of current EDF programmes, Mater. Sci. Technol. 6 (1990) 221-229. https://doi.org/10.1179/mst.1990.6.3.221
  5. N.S. Huh, Y.J. Kim, Y.J. Kim, Y.J. Yu, C.R. Pyo, Effect of nozzle geometry on leak-before-break analysis of pressurised piping, Eng. Fract. Mech. 68 (2001) 1709-1722. https://doi.org/10.1016/S0013-7944(01)00044-3
  6. M.L. Aggarwal, M.J. Kozluk, T.C. Lin, B.W. Manning, D.K. Vijay, A leak-before-break strategy for CANDU primary piping systems, Int. J. Pres. Ves. Pip. 25 (1986) 239-256. https://doi.org/10.1016/0308-0161(86)90102-X
  7. V.G. Ukadgaonker, R.S. Babu, Review of work related to 'leakbefore-break' assessment, Int. J. Pres. Ves. Pip. 69 (1996) 135-148. https://doi.org/10.1016/0308-0161(95)00124-7
  8. J. Chattopadhyay, B.K. Dutta, H.S. Kushwaha, Leak-beforebreak qualification of primary heat transport piping of 500 MWe Tarapur Atomic Power Plant, Int. J. Pres. Ves. Pip. 76 (1999) 221-243. https://doi.org/10.1016/S0308-0161(98)00134-3
  9. Y.J. Kim, Y.Z. Lee, N.S. Huh, C.R. Pyo, J.S. Yang, Development of modified piping evaluation diagram for leak-before-break application to Korean next generation reactor, Nucl. Eng. Des. 191 (1999) 135-145. https://doi.org/10.1016/S0029-5493(99)00136-3
  10. N. Gong, G.Z. Wang, F.Z. Xuan, S.T. Tu, Leak-before-break analysis of a dissimilar metal welded joint for connecting pipenozzle in nuclear power plants, Nucl. Eng. Des. 255 (2013) 1-8. https://doi.org/10.1016/j.nucengdes.2012.09.030
  11. L.Y. Du, G.Z. Wang, F.Z. Xuan, S.T. Tu, Effects of local mechanical and fracture properties on LBB behavior of a dissimilar metal welded joint in nuclear power plants, Nucl. Eng. Des. 265 (2013) 145-153. https://doi.org/10.1016/j.nucengdes.2013.07.028
  12. T. Wakai, H. Machida, S. Yoshida, Y. Xu, K. Tsukimori, Demonstration of leak-before-break in Japan Sodium cooled Fast Reactor (JSFR) pipes, Nucl. Eng. Des. 269 (2013) 88-96.
  13. Y. Tujikura, S. Urata, Fracture mechanics evaluation of cast duplex stainless steel after thermal aging, Nucl. Eng. Des. 191 (1999) 255-261. https://doi.org/10.1016/S0029-5493(99)00147-8
  14. S. Cicero, J. Setien, I. Gorrochategui, Assessment of thermal agingembrittlement in a cast stainless steel valve and its effect on the structural integrity, Nucl. Eng. Des. 239 (2009) 16-22. https://doi.org/10.1016/j.nucengdes.2008.09.009
  15. S.X. Li, H.L. Zhang, S.L. Li, Y.L. Wang, F. Xue, X.T. Wang, Probabilistic fracture mechanics analysis of thermally aged nuclear piping in a pressurized water reactor, Nucl. Eng. Des. 265 (2013) 611-618. https://doi.org/10.1016/j.nucengdes.2013.06.034
  16. X.M. Lv, S.L. Li, X.T. Wang, Y.L. Wang, Z.X. Wang, F. Xue, H.L. Zhang, Effect of thermal aging on the leak-before-break analysis of nuclear primary pipes, Nucl. Eng. Des. 280 (2014) 493-500. https://doi.org/10.1016/j.nucengdes.2014.10.012
  17. J.K. Sharples, A.M. Clayton, A leak-before-break assessment method for pressure vessels and some current unresolved issues, Int. J. Pres. Ves. Pip. 43 (1990) 317-327. https://doi.org/10.1016/0308-0161(90)90110-4
  18. G. Bartholome, R. Wellein, Leak-before-break behavior of nuclear piping systems, Theor. Appl. Fract. Mech. 23 (1995) 145-149. https://doi.org/10.1016/0167-8442(95)00015-7
  19. J. Xu, T. Chen, L. Yang, Two-phase critical discharge of initially saturated or subcooled water flowing in sharp-edged tubes at high pressure, J. Therm. Sci. 4 (1995) 193-199. https://doi.org/10.1007/BF02650828
  20. M.F. Kanninen, C.H. Popelar, Elasticeplastic fracture mechanics, in: Advance Fracture Mechanics, Oxford University Press, New York, 1985.
  21. S. Yang, Leak-before-break analysis for pickering 'A' unit 1 and unit 4 large diameter main steam line pipes, Nucl. Eng. Des. 240 (2010) 2589-2603. https://doi.org/10.1016/j.nucengdes.2010.06.040
  22. A. Zahoor, Ductile Fracture Handbook, in: Volume 1: Circumferential Through Wall Cracks, Electric Power Research Institute, Palo Alto, 1989. EPRI Report NP-6301-D.