UK Nuclear-Powered Submarines Banned From Visiting UK Commercial Ports: Reactor Problems Vindicate New Zealand’s Nuclear Propulsion Ban

By Commander Robert Green, Royal Navy (Ret'd)

28 May 2004

On 23 April 2004, sea trials of the UK nuclear-powered attack submarine (SSN) HMS Trafalgar were postponed for 24 hours after 11 crew members – including 3 out of the 4 specialist safety crew – refused to go to sea because of safety concerns. The submarine had just completed repairs after running aground off the Isle of Skye in November 2002. One sailor who refused to go to sea said 250 safety problems were still unresolved. Unusually, only one of the sailors was disciplined. This could be because the Royal Navy wants to avoid exacerbating morale problems in its nuclear submarine force caused by safety issues.

In other reports from reliable Royal Navy sources, serious doubts have emerged about the future viability of nuclear propulsion for UK submarines. Key factors include:

Shrinking of the shipbuilding and repair manpower base.


Nuclear Propulsion Problems.

UK SSN nuclear propulsion technical difficulties arose in about 1991 from cracks discovered in welds of the primary coolant loop within the nuclear plant’s steam generators (the aging Polaris nuclear-armed ballistic missile submarine force was also affected). Put simply, the welds were not strong enough to withstand the stresses placed on them, and repairs proved difficult and time-consuming.

When HMS Tireless discovered reactor coolant leaks in the Mediterranean nearly ten years later in May 2000, the Royal Navy judged them sufficiently serious not to risk steaming her back to the UK but to have them repaired in Gibraltar, causing protests and anxiety among the local population and in southern Spain until repairs were completed in April 2001. Further checks revealed that another six SSNs had the same defect. The US Navy had had similar problems in the 1980s with its 688 Class SSNs; but the US-UK special relationship had clearly not extended to sharing information on solving them.

One of the 11 concerned sailors in HMS Trafalgar reported that there were high radiation levels on the hull above the reactor compartment. This was probably linked to a known problem with the reserve control rods, which were not dropping as fast as they should in their key safety role of shutting down the reactor in the event of electrical failure.

In addition, a second reactor problem was discovered in HMS Sceptre in 2000, causing her refit to be extended by three years. In January 2002, the Ministry of Defence stated that “small original fabrication imperfections” had been found in the reactor pressure vessel. There was concern that another SSN of the same class, HMS Superb, could have the same serious defect, which probably required replacement of the pressure vessel.


UK Commercial Port Visits Banned

Concern about nuclear propulsion plant safety has always restricted the choice of UK ports which SSNs could visit. Both naval and commercial ports must provide a specific “Z berth” with a safety plan. Because of the reactor safety problems described above, the UK Nuclear Powered Warships Safety Committee was sufficiently worried to ban UK SSNs from foreign port visits in the early 1990s. Also, significantly, no UK SSN visited Southampton – which until 1989 had had a visit almost annually – between 1990-96, probably because of the reactor weld problem.

Currently, no SSN is allowed to visit any UK commercial port, where the only established Z berths now are in Liverpool and Southampton. Those in Cardiff and Hull have been closed, while Z berths in Swansea and Tilbury (London) proposed in 1989 still await approval. Indeed, SSNs are not permitted to enter the Pool of London, in Britain’s capital city, where all conventionally-powered warships smaller than aircraft-carriers traditionally berth. The fact that SSNs are not even cleared for Tilbury, at the mouth of the Thames, is an indicator of the potential hazard they pose.

In Southampton, since May 2001 the City Council has accepted that it could not cope with an accident and any associated compensation claims, and SSN visits are banned. It has produced a new contingency plan for the countermeasure zone around the Z berth, which is to be exercised next year, then evaluated before any SSN can use it. Meanwhile, Liverpool is off-limits awaiting resolution of a plan to distribute potassium iodate tablets to the local population as a precaution in the event of a nuclear disaster. The Department of Health states: “Stocks of potassium iodate tablets are held in the vicinity of all British nuclear reactors for immediate distribution in response to a nuclear accident involving the release of radioactive iodine. Further stocks of tablets are also held in case of overseas accidents…”.

Even in naval bases, safety concerns are being raised. For example, on 8 October 2003 the Portsmouth News reported that potassium iodate tablets had been issued to 80,000 people, including 34 schools, in Gosport – the home of the Submarine Service – and Portsmouth before the visit of the nuclear submarine HMS Torbay.


Implications for New Zealand

Soon after the 1992 Somers Report on the Safety of Nuclear-Powered Ships was published, classified UK contingency plans for a worst-case submarine reactor accident were leaked showing the need for evacuation to 10km. Since then, UK SSNs have had persisting nuclear propulsion safety problems, such that no British commercial port is prepared to accept its own SSNs and crew members are voicing concern. The New Zealand government is vindicated, therefore, in keeping its nuclear propulsion ban, which is not anti-American but pro-New Zealanders’ security.