PSI - Issue 13

Peter Trampus / Procedia Structural Integrity 13 (2018) 2083–2088 P. Trampus / Structural Integrity Procedia 00 (2018) 000 – 000

2088

6

KI Point 1 KI Point 6 KIc Point 1

(MPa  m)

K I values for the deepest (1) and near interface point (6) of a 23 mm deep crack (a/c=14/42 mm) vs K IC tangent curve

100

90

80

70

60

50

40

30

20

10

0

60 80 100 120 140 160 180 200 220 240 260 280 (°C)

0

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40

Fig. 3. K I and K Ic values: deepest point (1) and point nearest to the cladding-base metal boundary (6), during the transient LB LOCA.

T k allow value for a component was defined as the minimum of T k allow values calculated in various circumferential sectors of the RPVs. The allowable service life ( τ allow ) of a component is the maximum lifetime τ – measured in service years – for which T k ( τ ) ≤ T k allow . The allowable service life of an RPV is the minimum of τ allow values defined for components selected for fracture mechanics analyses. The results based on fracture mechanics analyses admit more than 60 years of operation for the allowable lifetime of RPVs 1 to 4 at Paks NPP. Acknowledgements The author would like to thank Messrs. G. Bona, J. Elter and S. Ratkai from Paks NPP, T. Fekete, F. Gillemot and A. Kereszturi from Centre for Energy Research, Hungarian Academy of Sciences, and Ms. E. M. Zsolnay from Institute for Nuclear Techniques, Budapest University of Technology and Economics, for their invaluable contribution to this work. ASTM E185-16, 2016. Standard Practice for Design of Programs for Light-Water Moderated Nuclear Power Reactor Vessels, ASTM International, West Conshohocken, PA Ballesteros, A. et al, 2003. Assessment of irradiation conditions in WWER-440 (213) RPV surveillance location (COBRA Project), In: Proc. Int. Seminar Networking for Effective R&D, Petten, Report EUR 20984 EN ENIQ Guideline, 2007. European Methodology for Qualification of Non-Destructive Testing (third issue), EUR 17299 EN, Luxembourg IAEA-EBP-WWER-08, 2006. Guidelines on Pressurized Thermal Shock Analysis for WWER Nuclear Power Plants (Rev. 1), IAEA, Vienna IAEA TECDOC 1627, 2010. Pressurized Thermal Shock in Nuclear Power Plants: Good Practices for Assessment, , IAEA, Vienna Marie, S., Chapuliot, S., 2008. Improvement of the calculation of the stress intensity factor for underclad and trough-clad defects in a reactor pressure vessel subjected to pressurized thermal shock. Int. J. Pressure Vessels and Piping 85, 517-531. References