Nuclear fault cripples submarines

The Navy has belatedly decided to withdraw to port 12 of its 16 nuclear powered submarines. This decision came as a result of an inspection of the reactor on HMS Tireless which is in Gibraltar following a serious accident which it had at sea on 12th May.

Up until now the Navy has tried to play down the scale of the problem on Tireless. It was initially described as minute crack. However on 21 October the Junior Defence Minister John Spellar admitted that the problem was ten times greater:

"We originally thought we were dealing with cracks of about two millimetres, now we are talking about cracks of a few centimetres .."

The problem is in a weld which joins the narrow loop to the pressuriser with the larger main circuit. This is shown in two diagrams: diagram one, diagram two. The fact that the crack is larger is very significant. It means that it extends into the main primary circuit pipe itself.

The Gibraltar government appointed several independent nuclear experts to give them advice on the repair to Tireless. From their report it is apparent that the Navy have been aware for some time that the crack could have been larger than they were admitting. In the light of this they should have withdrawn all the submarines from service in May when the accident happened and not waited until now. It is interesting that over the summer most of the submarines were kept in port, with the exception of the two which are armed with cruise missiles, HMS Triumph and HMS Splendid. It would appear that, until now, the Navy's operational requirements were placed above the needs for safety.

The Ministry of Defence has said that this could be a generic defect which could affect all Swiftsure and Trafalgar class submarines. However they have claimed that it does not affect the Trident armed Vanguard class because they have a different reactor. This statement should not be taken at face value. The Trident submarines have a PWR2 reactor whereas the older submarines use the PWR1. However the PWR2 is a development from the PWR1 and probably incorporates a lot of the same basic design features. Although the Trident submarines are newer, the oldest of them, HMS Vanguard, was launched only one year after HMS Triumph, which has been ordered to return to port.

The current deployment of British nuclear submarines on 22 October 2000 is as follows:

HMS Sovereign, Faslane, withdrawn from service on 8 Sep 2000, because of a reactor defect found on HMS Sceptre at Rosyth in 1998.
HMS Superb, Faslane, withdrawn from service on 8 Sep 2000, as with Sovereign.
HMS Sceptre, Rosyth, completed a refit in July, but has not sailed to Faslane.
HMS Spartan, Rosyth, in refit since March 1999.
HMS Splendid, left Faslane for sea on 16 October, probably off the West coast of Scotland and recalled to Faslane on 21 October.
HMS Trafalgar, Devonport, due to go to sea for trials, probably related to conversion to cruise, but kept in port on 21 October.
HMS Turbulent, Devonport, due to go to sea but kept in port on 21 October.
HMS Tireless, Gibraltar, undergoing inspection prior to repair.
HMS Torbay, Devonport, in refit scheduled to end in Feb 2001.
HMS Trenchant, Devonport, in refit since March 2000.
HMS Talent, Devonport, undergoing maintenance following discovery of a major defect.
HMS Triumph, Mediterranean, recalled to Devonport from Toulon, France, on 21 October.
HMS Vanguard, Faslane, probably not armed with missiles, due to go into refit in 2002.
HMS Vigilant / HMS Victorious, one of these two is on a nuclear patrol, the other is at Faslane.
HMS Vengeance, Kings Bay, Georgia, US, loading missiles, due to be operational in 2001.