The nuclear reactors which power the Royal Navy's fleet of submarines do not meet civilian standards of safety according to secret documents released to the Scottish Campaign for Nuclear Disarmament under the Freedom of Information Act.

A report from the Defence Nuclear Safety Regulator to the Defence Board warns that the Navy's current pressurised water reactor design compares "poorly" with that of nuclear power stations, and that the reactors are "potentially vulnerable to a structural failure of the primary circuit".  This could cause "a release of highly radioactive fission products" and pose "a significant risk to life to those in close proximity and a public safety hazard out to 1.5km from the submarine."  A reactor failure could prevent a submerged submarine from surfacing, resulting in "multiple fatalities".

The current PWR2 reactor design is scheduled to be installed in the Navy's fleet of new Astute class submarines, which will remain in service for 20 years or more.  Debate over whether to use an existing reactor design or a new US-based design in replacements for the Vanguard Class Trident missile submarines is thought to be the main cause in the delay of an announcement on the 'Initial Gate' in the Trident replacement programme.

More details and a copy of the Defence Board report released under the Freedom of Information Act can be found here.