Nuclear power officials said the activists were in the outer perimeters of the nuclear power stations and posed no security threat.
STOCKHOLM, Sweden—Swedish police arrested four activists on after they spent 28 hours hiding in the grounds of a nuclear power station in southwestern Sweden.
Greenpeace said two other anti-nuclear protesters were still hiding at another plant on the eastern coast.
Nuclear power officials said the activists were in the outer perimeters of the nuclear power stations and posed no security threat. The campaigners say they were trying to highlight what they say is poor safety at Swedish nuclear sites.
The four demonstrators were among some 20 people who entered the Ringhals reactor site on Tuesday morning by breaking chains on an outer perimeter gate. Fifty others scaled the outer fences of the Forsmark reactor site, Greenpeace said. Most of the activists were detained soon after illegally entering the enclosures, the environmental group said.
“We still have two guys at the Forsmark site who have not been found,” Greenpeace spokeswoman Birgitte Lesanner said. “It just goes to show how bad the security is.”
She said some activists cycled into the fenced-off outer perimeter of one of the plants, and that recent European Union stress tests on nuclear facilities should have paid more attention to securing access to the plants. “People can just go in, like we did on bikes,” she said.
Nuclear power officials maintain that the campaigners did not pose a safety risk by entering the low-security area.
“It’s an industrial area like any other industrial area with a fence. It’s a big area, 50-60 hectares (120-150 acres) with some buildings, warehouses, lots of trees and unused land,” Ringhals spokesman Gosta Larsen said. “It’s prohibited to stay inside the private area without a permit, but they did not compromise security at all.”
The activists did not enter the high-security zone—the closely monitored area where the reactors are situated, surrounded by multiple fences, alarms and gate guards.
Sweden has 10 nuclear reactors providing about half of the country’s electricity. They are located at the country’s three power plants: Ringhals, Forsmark and Oskarshamn.
Its nuclear industry has come under fire for the lack of safety precautions. In June, a small amount of explosives was found on a forklift at the Ringhals plant but officials were unable to say how it got there.
Last year, a fire broke out in a Ringhals reactor after staff had left a vacuum cleaner in the containment building.
In 2010, Greenpeace activists broke into the Forsmark power plant site by climbing a fence and staged a demonstration.