Devonport Royal Dockyard Ltd (DRDL), the company which runs the Devonport naval base on behalf of the Ministry of Defence, has applied to the Environment Agency for permission to increase the quantity of radioactive carbon released into the atmosphere from operations at the dockyard.
DRDL say that the increase is needed to allow the refit of HMS Vanguard to proceed to schedule. HMS Vanguard, a nuclear-powered and nuclear-armed Trident submarine, is currently undergoing an unscheduled second refit at Devonport. The refit was ordered following the discovery of a radioactive leak in a test reactor at the Naval Reactor Test Establishment at Dounreay, and was deemed necessary as a precaution to ensure that the reactor in Vanguard – the oldest submarine in the Trident fleet – did not develop a similar defect.
The radioactive carbon (C-14) is released during primary circuit decontamination operations, during which radioactive products which have accumulated in the nuclear steam raising plant associated with the reactor are removed. During a previous refit for the submarine HMS Vigilant, quarterly notification levels for C-14 releases (above which DRDL is obliged to notify the Environment Agency) were exceeded, and DRDL considers that the increase in discharge limits is necessary to prevent this from happening again.
The application proposes to increase the permitted annual limit for atmospheric
discharges of C-14 from Devonport Dockyard from 43 to 66 Giga Becquerels – an
increase of over 50%. C-14 would be released directly to the atmosphere. DRDL considers that this is the best available technique for dealing with C-14, as abatement techniques “are costly and require high energy consumption”.
Because of its relatively long half-life and disposition to organically bind to cell constituents, ionising radiation from C-14 can cause cell damage with corresponding impacts on human health, and the radiation dose commitment and the dose rate from C-14 are significant.
The Environment Agency has undertaken public consultation on the DRDL application and is currently considering the results of consultation before coming to a decision.
Nuclear Information Service has written to the Environment Agency to object to the proposal, and a copy of our submission is available to download here: