The Royal Navy is investigating an incident in which a dummy torpedo was accidentally fired from a warship at a dockyard where nuclear powered submarines are berthed and maintained.
The accident took place in March 2014 when an unarmed Sting Ray torpedo used for testing was fired from HMS Argyll, one of the Navy's 'Duke' class Type 23 frigates, towards the nuclear licensed site within HM Naval Base Devonport in Plymouth.
According to the Navy the torpedo was “jettisoned unexpectedly” while system tests were underway during routine maintenance activities on board the warship.
Witnesses said the 9 foot missile flew around 200 yards through the air from a launch tube on the the starboard side of the frigate, ripped a hole in a wharfside security fence and collided with a storage container.
The Office for Nuclear Regulation (ONR) said that there we “no nuclear, radiological or conventional safety consequences” following the accident other than minor damage to the fence, which borders the nuclear licensed site at Devonport where submarines are berthed and maintained.
After the torpedo launch the Commander of the Base issued an embargo on all weapon testing at Devonport and the Ministry of Defence has commenced an investigation into the incident and safety management arrangements at the base. ONR and the Defence Nuclear Safety Regulator will determine whether enforcement action is necessary following the investigation.
In a statement on the accident the Royal Navy said:
"We can confirm an incident occurred on board HMS Argyll on March 12 at 3.24pm, while the ship was alongside at Devonport naval base in Plymouth."
"During a training exercise, an inert Test Variant Torpedo unexpectedly jettisoned onto the wharf. There was no explosion and no casualties.
"An investigation is now under way to determine the cause of the incident. The torpedo is not an explosive hazard.
"The specific details of the incident are subject to further investigation and it would be inappropriate to comment further.
"The result of the investigation will determine what actions will be necessary to avoid any repeat of this incident in the future.
"However, torpedo system test firing alongside in the naval base has been suspended subject to completion of the investigation."
The operators of the Devonport Dockyard, Devonport Royal Dockyard Ltd (DRDL), are also investigating a separate incident which occurred at the site in January 2014, when radioactive waste from nuclear-powered HMS Trenchant which had been placed in a temporary radioactive store was inadvertently transported off the nuclear licensed site. Details of the type and quantities of waste have not been disclosed.
The matter is being treated as a 'loss of control' of radioactive material, and arrangements for tracking and accounting for radioactive materials across the site have been reviewed following the incident. ONR and the Environment Agency will consider whether regulatory action is necessary in the light of the findings of the DRDL investigation.