Stockholm, Dec 8 (IANS): One of Sweden's nuclear reactors will operate at a rate of around 50 per cent this weekend, at a time when electricity prices are unusually high and some of the country's other reactors are also off-grid.

"Reactor 3 at the Ringhals nuclear power plant will run at half its output for two days from the early hours of Saturday, December 10," Anna Wallrud, Deputy Press Manager at Ringhals, told Xinhua on Wednesday, "This is done to check, and potentially fix, its generators."

The fault occurred in one of the generators, which must be investigated. Between 4 a.m. on December 10 and 12 midnight on December 11, the reactor will deliver 537 megawatts (MW), about half its usual 1,074 MW output, the company said.

"General Electric, which is our supplier, has alerted us to a generic fault that can be present in this type of construction. In this case, it is a precautionary measure necessary to prevent a longer stoppage in the future," Wallrud told Xinhua.

Wednesday's announcement means that three of Sweden's six nuclear reactors will simultaneously be idle or run at a lower output, Xinhua news agency reported.

Ringhals 4, the sister reactor of Ringhals 3, was taken off-grid for repairs in August and is scheduled for restart in late February.

Starting from Friday, December 9, reactor 3 at the Oskarshamn nuclear power plant will be disconnected for nine days to fix a faulty generator.

When the Oskarshamn stoppage was announced last week, Magnus Genrup, Head of the Department of Energy Sciences at Lund University, told Dagens Nyheter (DN) newspaper that it exposed the vulnerability of Sweden's energy system.

"This shows that we have no margins anymore, and that is serious," he said.

According to the Swedish Radiation Safety Authority, several nuclear reactors were decommissioned between 2017 and 2020, widening the gap in electricity prices between different regions.

Recently, prices in the south have peaked at around 8 Swedish kronor (nearly 77 US cents) per kWh.

According to Statistics Sweden, electricity prices increased by an average of 25.6 per cent in October compared to the same month last year. (1 Swedish krona = 0.096 US dollar)