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New reactor for Trident may be built at Dounreay

The Scottish Campaign for Nuclear Disarmament has revealed
that Government plans to replace the Trident nuclear weapon
system could result in a new nuclear reactor being built at Dounreay,
Rear Admiral Matthews, who is heading the programme to replace
Trident, has said that a new design of reactor will be required
for the new submarines.  Rolls Royce have indicated that this
will use a substantially different process than earlier submarine
reactors.  This means that a land-based prototype will be required. 
The prototypes for both of the earlier Naval reactors, PWR1 and
PWR2 were both built at HMS Vulcan, Dounreay.   The PWR2
prototype is operational today and is due to close in 2014. 

Nick Harvey, Liberal Democrat Defence Spokesperson, put down

a written question to Des Browne asking if the MoD were planning

to design a new reactor for the new Trident submarines.  On

13 June 2007 Des Browne replied saying:


“Decisions on whether or not to develop a replacement for PWR2

have not yet been taken.” (1)


However Rear Admiral Matthews, Director General Nuclear, said in

April in the MoD magazine Preview that the Future Submarine programme

will involve “the design of a new generation of nuclear power plant”. (2)


Submarine reactors are designed and built by Rolls Royce Marine.  In January 2007 one member of staff was moved

to work on concept studies for a new generation nuclear propulsion plant. The job description for a position at

Rolls Royce, advertised in February 2007, also refers to work on the new reactor. (3)


In November 2006 Steve Ludham, the President of Nuclear Business at Rolls Royce, appeared before the House

of Commons Defence Committee.  He argued that a new reactor should be produced.  This new plant would be

“passive”.  It would be able to function without relying on coolant pumps. (4)  The current PWR2 reactors on

British submarines cannot operate without coolant pumps.  Mr Ludham argued that this innovation would make

the reactor safer.  However the main motivation behind this design change is that it makes a submarine quieter.


Natural circulation was first used by the US Navy in the S5G reactor on USS Narwhal.  As a result Narwal was

the quietest submarine of its day.  Derivatives from the S5G design have been installed on US Trident submarines. 

The US Navy has not supplied the UK with information on this type of reactor.  The new proposal would be a

Rolls Royce design.


As the new reactor would be substantially different from the current design, a land-based prototype would be

required.  This prototype would be functioning around 4 years before the first submarine reactor was operational. 

This would give a target date of 2018, 4 years before Contractors Sea Trials of the first of the new submarines

which are planned to replace Trident.


British submarines have been powered by two types of reactor, PWR1 and PWR2.  In each case before the reactor

was built into any submarine it was first tested in a prototype at HMS Vulcan.  This is an MoD facility, operated

by Rolls Royce, at Dounreay. The current contract for HMS Vulcan runs until 2014, after which it is assumed that

the PWR2 prototype will be decommissioned.


It appears that the MoD are preparing to design a new reactor for the new Trident submarine.  A final decision

may not yet have been made on this.  A new reactor will need a land-based prototype.  It is not clear if this

will be at Dounreay, but it is the most obvious site.


The first experimental reactors were built at Dounreay because the authorities were worried about the effect
of a nuclear disaster.  Caithness was considered to be a suitably remote location for dangerous nuclear trials. 
The prototype reactor for the new Trident submarines will use an novel design.

John Ainslie, Scottish CND Coordinator said


“If there was a major accident then a large part of the North of Scotland could be contaminated. 
The majority of Scots oppose the construction of new nuclear plants.  The MoD should scrap their plan 
for new Trident submarines and with it the prospect of building a new reactor at Dounreay.”

(1) Hansard 13 June 2007

(2) Preview, MoD, April 2007, page 15.  http://www.mod.uk/NR/rdonlyres/34EC9779-7366-4081-A128-62B7C84E6820/0/200704_Preview_April07.pdf

(3) Job advert for Materials Engineer at Rolls Royce,  www.iom3.org/materialsworld/feb07/5feb07.htm

(4) The Future of the UKÂ’s Strategic Nuclear Deterrent: the Manufacturing and Skills Base, House of Commons Defence Committee, HC 59, 12 December 2006.  Evidence page 8.

Scottish CND 19 August 2007

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