Not a happy time in the sub business.
Radioactive water leaks from nuclear submarine HMS Trafalgar
A British nuclear submarine leaked hundreds of litres of radioactive waste into a river, it has emerged.
Environment watchdogs are investigating the leak at Devonport, in Plymouth, from HMS Trafalgar in which 280 litres of contaminated water were spilled.
The Environment Agency threatened to prosecute the Ministry of Defence or Devonport Management Limited after a series of spills in 2005.
The water, which amounts to more than quarter of a ton, was being removed from the submarine's cooling system and pumped into an effluent tank on shore.
It contained low levels of the radioactive element tritium which were picked up as the water was used to cool the reactor on board the submarine.
The water drained into the River Tamar at Devonport because a hose leaked as the contaminated water was being transferred.
The water was due to be removed and either decontaminated or disposed of as low level nuclear waste.
The spill is the largest in 23 years but tests in the river have showed no signs of increased radiation and the Environment Agency says there is no risk to the public.
A nuclear expert criticised the Ministry of Defence for withholding details of the spill for four days after the accident early on Friday morning.
Nuclear consultant John Large said the leak represented a potential risk to workers at the dockyard and was a serious breach of safety procedures.
He said: "This is very serious because it means there has been a breakdown in nuclear safety protocols.
"The risk to the public is virtually zero but there was a risk to the workers who may have been exposed to this without being aware of it.
"They could have transferred it to other areas of the yard where nuclear safety controls are not in place on their shoes or clothing.
"Systems are in place to stop this sort of leak happening so the very fact that it did means that something has gone seriously wrong.
"There is an underlying problem of accountability and the Ministry of Defence have only described this incident a few days after it occurred."
Ian Avent from the Plymouth-based Campaign Against Nuclear Storage and Radiation said: "It is the worst accident I have heard of. It beggars beliefs it could have happened at all.
"We are lucky the consequences of all the incidents we have had in the dockyard have not been far, far worse. How long are we going to rely on the management being lucky?
"We are relying on their handling of these dangerous processes not just for our health and safety but for our lives.
"This does not inspire any confidence in them at all."
A spokesman for the Royal Navy said no-one had been hurt in the incident and the vessel's nuclear power plant was unaffected.
He said: "Shortly after midnight on the night of November 6/7, during a standard operation to transfer primary coolant from HMS Trafalgar to an effluent tank on the jetty, a hose ruptured, resulting in a leak of the coolant.
"A maximum of 280 litres of coolant were discharged from the hose onto the submarine casing, jetty and into the Hamoaze area of the river Tamar.
"As soon as the leak was discovered, the transfer was stopped, the area was quarantined, monitoring and sampling carried out and a clean-up operation completed.
"Initial sampling has not detected any radioactive contamination in the local environment.
"The environmental risk is assessed to be negligible and analysis of river water has not shown any detectable contamination.
"Investigations into the cause of the rupture are ongoing and will lead to remedial action as necessary to prevent this incident from re-occurring.
"This incident has not affected the submarine's programme."
A spokesman for the Environment Agency said: "Our role is to regulate the site to ensure the protection of people and the environment.
"We are certain there is no significant environmental impact, but we have taken our own samples for reassurance purposes and these are in addition to the monitoring carried out by the Ministry of Defence.
"We will investigate the circumstances of this unauthorised discharge and make sure that all necessary measures are taken to stop it happening again."