The number of radiation safety incidents at the Clyde naval base where the UK's Trident nuclear weapons submarines are based has risen by more than 50 per cent over a year, according to figures released by the Ministry of Defence.
105 nuclear safety events were recorded during the 2013-14 year at the Faslane submarine base and Coulport nuclear weapons store, which comprise HM Naval Base Clyde – up from 68 in 2012-13.
The majority of the incidents – 99 – related to the nuclear propulsion systems which power the Royal Navy's submarines, with a further six incidents recorded which involved nuclear weapons.
The figures were provided in response to Parliamentary Questions asked by Scottish National Party (SNP) MP Angus Robertson enquiring how many nuclear safety events there were at HMNB Clyde over each of the last six years.
The answer reveals that on two occasions safety arrangements at the Coulport nuclear weapons store were deliberately broken by management. Twice in 2009 a limit for the total number of annual lifts for a crane at the Coulport Explosives Handling Jetty was exceeded. The limit, imposed for safety reasons in order to guarantee the structural reliability of the crane, was first breached in February 2009. Following the breach a concession was granted to allow further lifts to take place – but the new limit was exceeded on 20 March 2009 “for operational support purposes”.
In another incident, which occurred on 17 August 2012, an “inadvertent radiation dose” was received by contractors who were working on a submarine tank. The incident was classified as a 'category B' incident – one of twelve such incidents that took place at the base over the last six years - meaning that it resulted in “actual or high potential for a contained release within building or submarine or unplanned exposure to radiation”, according to HMNB Clyde's nuclear safety event reporting definitions.
Other Category B incidents that took place over this period included removal of temporary shielding from a valve in a submarine reactor compartment without correct authorisation, shutting of steam valves designed to relieve pressure in reactors outside normal operating procedures, and a spill of water from a submarine reactor compartment when a freeze seal melted during valve maintenance work.
All twelve category B incidents listed related to naval nuclear propulsion systems, and none were recorded which involved nuclear weapons. No category A incidents - those with actual or high potential for radioactive release to the environment or over exposure to radiation – were recorded over the six year period.
The string of incidents raises concerns over standards of nuclear regulation at the Clyde nuclear base. Work undertaken by the Royal Navy at the base is regulated by the secretive Defence Nuclear Safety Regulator – an internal group within MoD – rather than the Office for Nuclear Regulation (ONR), which oversees civil nuclear regulations. Similar incidents which have occurred in the civilian sector have resulted in enforcement action and even prosecution by ONR, but no such action has been taken over accidents at the Clyde base.
Angus Robertson MP, Westminster leader and defence spokesperson for the SNP, described the figures as "totally shocking" and “unacceptable”.
"These figures indicate how widespread nuclear safety breaches are," he said. "We must have an absolute assurance from the MoD that safety concerns are given then highest priority."
Defence minister Philip Dunne said “None of the events in the reports caused any harm to the health of any member of staff on the Naval Base, or to any member of the public, and the severity of the reported events has remained at a very low level”.
The MoD has not given details of all the incidents which occurred over the six year period, but stressed that most of them were minor and did not endanger the health of workers or the public.