Eight representatives from a Norweigan campaign group descended on Sellafield and demanded that the site halts any further “intake” of nuclear waste.
Campaigners from Neptune Network blocked a section of the Carlisle to Barrow railway line to the south of the Sellafield site, which is used for deliveries in and out of the site.
Cumbria Crack understands that the protestors agreed to move out of the way of oncoming trains.
They have carried out a number of actions against the facility since 2001.
“Neptune Network demands a halt in the reception of more nuclear waste at the plant,” one tweet by the group said.
Another said: “Neptune Network demands that the British authorities take action, and urges the Norwegian state and the Norwegian people to reinforce this message. Neptune Network demands a full stop in receiving nuclear waste now!”
Waste from the UK’s 11 nuclear facilities is managed and stored at Sellafield, which a spokesman for the site said was “essential to keeping those nuclear sites running and keeping the lights on”.
About 20 per cent of the UK’s electricity is generated by nuclear.
All waste is stored safely and securely, said the spokesman.
Sellafield said it worked with British Transport Police to ensure the protest ran safely.
“We’re aware of this pre-planned protest by the Neptune Network on public land close to the Sellafield site,” the Sellafield Ltd spokesman said.
“Our policing colleagues will ensure this activity takes place safely and without undue disruption to the public or our operations.
“We are proud of our environmental performance and our role in ensuring the UK manages its nuclear legacy safely and responsibly.
“Like every other day, we will be focusing on our purpose: creating a clean and safe environment for future generations.”
A spokeswoman for the British Transport Police said: “British Transport Police attended the line near Sellafield at 7am yesterday morning following reports of a demonstration near the tracks,” she said.
“Some services on the line were delayed and officers continued to patrol the area however no issues or incidents occurred.”
