The Paton Welding Journal, 2015, №01



2015 №01 (07)

DOI of Article 10.15407/tpwj2015.01.08

2015 №01 (01)

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The Paton Welding Journal, 2015, #1, 49-54 pages  

EVALUATION OF OPERABILITY OF WWR-M REACTOR PRIMARY CIRCUIT PIPING WITH WELDED JOINT DEFECTS

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: office@paton.kiev.ua
 
 
Abstract
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.
 
 
Keywords: aluminium piping, defect admissibility, mathematical modeling, brittle-ductile fracture, stress-strain state, numerical evaluation, load-carrying capacity
 
 
Received:                20.10.14
Published:               28.02.15
 
 
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