TPWJ, 2015, #1, 49-54 pages
EVALUATION OF OPERABILITY OF WWR-M REACTOR PRIMARY CIRCUIT PIPING WITH WELDED JOINT DEFECTS
Journal The Paton Welding Journal
Publisher International Association «Welding»
ISSN 0957-798X (print)
Issue № 1, 2015 (January)
O.V. Makhnenko, A.S. Milenin And G.Yu. Saprykina
E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: email@example.com
Evaluation of load-carrying capacity of critical welded piping elements based on the results of technical diagnostics of their state is an important stage of a package of measures to confirm their operability and remaining safe operating life. In particular, in the case of detection of various defects of material discontinuity, it is necessary to perform static strength analysis of the piping and analysis of its strength factor correspondence to design requirements. If it is confirmed that the detected defects only slightly lower the piping load-carrying capacity, it can be allowed to operate in precised modes of force and corrosion impact. It is proposed to apply ductile fracture criterion based on multidimensional finite-element analysis of elastoplastic strain development. Admissibility of crack-like defects is substantiated by brittle-ductile fracture criteria. The case of an aluminium piping element of WWR-M research reactor primary circuit with detected multiple discontinuities of the weld (gas pores, nonmetallic inclusions) was used to show the sequence and main principles of analysis of defective piping load-carrying capacity. Community of the proposed methodological approaches allows their application at confirmation of operability of critical piping and pressure vessels from aluminium alloys and high-strength steels. 14 Ref., 1 Table, 7 Figures.
aluminium piping, defect admissibility, mathematical modeling, brittle-ductile fracture, stress-strain state, numerical evaluation, load-carrying capacity
1. (1991) PNAE G-7-023-90: Equipment and pipelines of nuclear power plants. Aluminium alloy welded joints. Rules of control. Moscow: Energoatomizdat.
2. (1991) PNAE G-7-010-89: Equipment and pipelines of nuclear power plants. Welded joints and deposits. Rules of control. Moscow: Energoatomizdat.
3. (1987) PNAE G-7-002-86: Norms of strength analysis of equipment and piping of nuclear power plants. Moscow: Energoatomizdat.
4. Makhnenko, V.I. (1976) Calculation methods for the study of kinetics of welding stresses and strains. Kiev: Naukova Dumka.
5. Makhnenko, V.I., Velikoivanenko, E.A., Pochinok, V.E. et al. (1999) Numerical methods for the prediction of welding stresses and distortions. In: Welding and Surfacing Rev., Vol. 13. Amsterdam: Harwood Acad. Publ.
6. Makhnenko, V.I., Kasatkin, O.G., Velikoivanenko, E.A. et al. (1998) Calculated-experimental study of welding stresses in the zone of circumferential butts of pipelines DU-300 of ChNPP-3 KMPTs. In: Proc. of 5th Int. Conf. on Problems of Materials Science in Design, Manufacturing and Service of Nuclear Power Plant Equipment (Pushkin, Russia, 1998), Vol.2, 53-66. St.-Petersburg: FGUP TsNII KM Prometej.
7. Makhnenko, V.I. (2013) Problems of examination of modern critical welded structures. The Paton Welding J., 5, 21-28.
8. Karzov, G.P., Margolin, B.Z., Shvetsova, V.A. (1993) Physical-mechanical modeling of fracture processes. St.-Petersburg: Politekhnika.
9. Procedural recommendations MR-125-01-90: Calculation of stress intensity factors and section weakening for defects in welded joints. Kiev.
10. Zvezdin, Yu.I., Rivkin, E.Yu., Vasilchenko, G.S. et al. (1990) Application of data of nondestructive testing in strength analysis. Tyazh. Mashinostroenie, 3, 12-14.
11. Procedural recommendations MR-125-02-95: Rules for plotting design diagrams and determination of parameters of loading of structural elements with detected defects. Moscow: NPO TsNIITMASh.
12. Ovchinnikov, A.V., Zubchenko, A.S. (2010) Interpolation formulae of calculation of stress intensity factors for pressure vessels and pipelines. In: Problemy of nuclear science and engineering. Series Safety assurance of NPP. Issue 27: Reactor plants with WWER. Problems of strength, 58-70.
13. Milne, L., Ainsworth, R.A., Dowling A.R. et al. (1988) Assessment of the integrity of structure containing defects. Int. J. Pressure Vessels and Piping, 32(1-4), 3-104. https://doi.org/10.1016/0308-0161(88)90071-3
14. Makhnenko, V.I. (2006) Residual safe operating life of welded joints and sub-assemblies of modern structures. Kiev: Naukova Dumka.