Mitsubishi Heavy Industries Ltd (MHI) has held a ceremony at its Kobe works in Japan to mark completion of three of the nine replacement steam generators ordered by EDF. MHI was selected to supply the steam generators through an international bidding process and won the order jointly with long-standing collaborator Onet Technologies of Marseilles, which provides specialised after-sales service and maintenance for NPP facilities. MHI has been collaborating with Onet since 2002.
The steam generators – each about 21 metres high and weighing some 330 tonnes – are pressure-resistant vessels made with strong low-alloy steel (steel with not more than 5% alloying element). According to MHI, each steam generator contains more than 4,500 heat transfer tubes made of TT690 – a state-of-the-art nickel, chromium, and iron alloy, specially heat-treated for enhanced corrosion resistance. High machining accuracy is required in their manufacture - in the order of 0.01 mm.
To date, MHI has supplied 31 replacement steam generators for reactors in France, Belgium and the USA. These include 15 for EDF, which is replacing steam generators at its PWR plants that started operations in the 1980s as part of plans to extend the plants' operating periods beyond 40 years.
Image: MHI has held a ceremony at its Kobe works in Japan to mark completion of three of the nine replacement steam generators ordered by EDF for its nuclear plants in France, Belgium and the USA (courtesy of MHI)
