Applicability of risk-based maintenance strategy to a penstock

Abstract

The risk of brittle fracture of the penstock of the reversible pump turbine is recognized in an early stage of design. To reduce the cost of penstock construction one tunnel is accepted. The HSLA steel of 700 MPa yield stress, 47 mm thick, is selected for the most stressed penstock section. It was necessary to assure structural integrity of welded joints and the penstock structure by involving an appropriate maintenance and repair approach. Maintenance procedures are in continuous development, and the most promising probably is the risk-based approach, developed recently. Basic requirements of this approach are considered in the paper, and the possibility and convenience to apply them for the penstock is evaluated.

Rizik od krtog loma cevovoda reverzibilne turbine je ocenjen u ranoj fazi projektovanja. Da bi se smanjili troškovi izgradnje cevovoda prihvaćen je jedan tunel. Zbog toga je za najopterećeniji segment cevovoda izabran HSLA čelik, 700 MPa napona tečenja, debljine 47 mm. Bilo je potrebno i da se osigura integritet zavarenih spojeva i konstrukcije cevovoda uvođenjem odgovarajućeg pristupa za održavanje i opravke. Postupci održavanja se neprekidno razvijaju, a možda su najperspektivniji postupci zasnovani na riziku, razvijeni poslednjih godina. U radu su razmotreni osnovni zahtevi novih pristupa, i ocenjena je mogućnost i pogodnost njihove primene na cevovod.