Located approximately 60km south of Göteborg, Sweden's second largest city, the Ringhals nuclear power plant features four reactors, which were commissioned between 1975 and 1983.
The work, which is part of a contract awarded earlier by Sweden’s Ringhals, involved replacement of a nozzle welds with an alloy of higher corrosion resistance at the 1034MW unit-3 reactor in order to its improve reliability.
Ringhals is jointly owned by Vattenfall with 70.4% stake and Sydkraft Nuclear Power 29.6% interest.
As part of the contract, MHI was responsible to perform technical assessment, verification tests, equipment manufacture, material procurement and replacement work at the Ringhals site.
During the plant’s approximately two months of planned outages, MHI increased the high-temperature and pressure corrosion resistance of six nozzle welds of the pressurizer through the replacement of the Alloy 600 nickel material with high chrome content Alloy 690 nickel material.
Ringhals project manager Roland Gabrielsson said: "MHI has performed very complicated work in a difficult environment in the reactor building. The work has been completed to the highest quality, on schedule and in a safe manner."
Installed in the primary PWR cooling equipment, the pressurizer is an important component that maintains the reactor system at a constant pressure, MHI said.
The nuclear project produces around 28TWh of power annually, accounting for 20% of the total electricity used in Sweden.
Image: The Ringhals nuclear power plant in southern Sweden. Photo: courtesy of User Tubaist on sv.wikipedia.
