TRIDENT submariners were guilty of a “prolonged and repeated failure” which resulted in 20 workers being exposed to radiation at the Faslane nuclear base, according to an internal investigation by the Ministry of Defence (MoD). The damning indictment is published in MoD documents seen

by the Sunday Herald that also

expose a series of radiation blunders

on Trident submarines docked at the Clyde naval port.

They reveal how safety procedures were flouted when visitors were not given radiation badges, a contaminated sponge was taken from a submarine, and another worker was irradiated. The documents, just released a full two years after a Freedom of Information request, conclude that submariners showed a “lack of understanding of the magnitude of the hazards”.

The revelations have prompted alarm from experts and politicians, who are demanding a major overhaul of safety at Faslane. Campaigners have lambasted the MoD for “sticking two fingers up at nuclear safety laws”.

Prospect, the trade union representing Faslane engineers, promised to support workers worried about radiation poisoning. “Our thoughts and concerns are with those staff and members who have been exposed to increased radiation doses through no fault of their own,” said the union’s negotiations officer, Richard Hardy.

“Any incident which involves exposure to radiation is of concern and we will work to ensure any lessons learned are taken forward as a matter of urgency and also to ensure that staffing and knowledge levels within this critical facility are maintained at the appropriate level.”

MoD reports on four radiation incidents on Trident submarines at Faslane in 2012 and 2013 have been released by the UK Government’s Office for Nuclear Regulation under FoI law. The documents have been heavily redacted at the MoD’s request to keep the submarines names, some radiation measurements and other details secret.

On August 16 and 17, 2012 workers with an MoD contractor were repairing a large leaking tank on a Trident submarine moored at Faslane. What they didn’t know was that for more than 24 hours the submarine reactor nearby was being operated and exposing 20 of them to potentially hazardous radiation.

According to an MoD investigation, the workers’ team leader specifically queried whether radiation controls in the tank were adequate. But he was “incorrectly reassured” by naval officials that doses were within acceptable limits. “There was a prolonged and repeated failure of the ship’s staff to understand and control the radiological hazard that they were creating,” concluded the MoD report.

Naval staff showed a “lack of understanding of the magnitude of the hazards present when operating a reactor”, it said. An initial survey carried out by a trainee had given a “false indication” of radiation levels in the tank.

“Employees were within the tank for more than 24 hours with no controlled area established, no approved dosimetry and no other radiological control in place,” the report said.

Naval safety briefings to workers were “reported to be cursory or non-existent”, it added. There was “major concern” about misinformation on reactor power levels and “poor communication”.

The MoD’s investigation was hampered by the fact that submariners involved couldn’t be interviewed. They set sail on stealth patrol of the oceans with Trident nuclear weapons immediately after the incident.

Another mishap occurred on December 23, 2013 when a worker was irradiated by opening grilles to inspect a submarine tank. On April 25, 2012 a training team visiting a submarine were not issued with radiation badges as they should have been, and on February 14, 2013 a sailor working on a submarine mistakenly returned to his office with a contaminated “sponge bung”.

Fred Dawson, a retired MoD senior radiation expert, told the Sunday Herald that the August 2012 incident “highlights significant shortcomings in the management arrangements which led to personnel receiving avoidable and significant doses of radiation”.

The independent nuclear consultant, John Large, thought that civilian workers had been “badly let down” by a series of naval errors. “I daren’t imagine the outcome if a similar incident occurred while the boat was on patrol,” he said. “To have allowed these workers to have entered a tank connected to the nuclear reactor while it was under operation was daredevilry and an absolute disregard of the safety protocols.”

The SNP’s defence spokesman at Westminster, Brendan O’Hara MP, accused the MoD of “a very poor approach to radiation safety” at Faslane. “These incidents and how they were subsequently handled, pose real and serious questions about nuclear safety procedures at the base,” he said.

The MoD reports were obtained by the Nuclear Information Service, a campaign group that opposes nuclear weapons. “The navy is acting as a law unto itself and sticking two fingers up at nuclear safety laws designed to protect its personnel,” said the group’s Peter Burt.

The MoD stressed that safety at Faslane was of paramount importance. “None of the events in this report caused harm to any member of staff or public,” said a spokeswoman.

“Investigations were carried out and measures put in place to prevent such incidents from occurring again. We continue to conduct rigorous monitoring as part of our commitment to maintain the highest standards.”