Select Committee on Defence Written Evidence

Supplementary memorandum from Professor Richard L Garwin

  These brief comments respond to those aspects of the Ministry of Defence Testimony of 6 February 2007 that bear on my written evidence and oral testimony of 23 January 2007.  I have been authorized to write on behalf of my colleagues, Philip Coyle, Ted Postol, and Frank von Hippel.

  In response to our statement that the Vanguard class SSBN could well have its operational life extended by 15 years, as was the case with the US Ohio class, the MoD refers to the various systems that would have to be maintained and perhaps replaced if this life extension were to be achieved, and they summarize with the assertion that "the evidence that we have suggests that it would be poor value for money." Before the MoD can reach a conclusion (going beyond "suggests"), there should be a breakdown of costs by subsystem, and a discounted-present-value analysis of the options of new construction vs. life extension, as we indicated in our written evidence. There should be an explicit discount rate for the comparison of the alternatives.

  Defence Minister has rejected the observation that the reduced at-sea hours for Vanguard in comparison with the Ohio-class should make an operational life of 45 years easier to achieve because "The critical time from the point of view of when we measure the life of a boat is from when the reactors first go critical. My understanding is that you may well be able to bring the boat in but you cannot switch the reactor off and there are other parts of the system which will age no matter whether the boat is at sea or not, . . . " Detailed description of the maintenance cycle of the Trident submarines has been provided by the US Navy[125] in an article describing the 200th dry-docking of an Ohio-class SSBN at the Intermediate Maintenance Facility, Bangor, Maine. These refits, taking 18-22 days are "designed to be incremental overhauls, conducted approximately three times a year for each TRIDENT boat." The reactor does not operate while the SSBN is in dry-dock.

  Adding to the confusion is that Rear Admiral Andrew Mathews either misspoke or that the transcript understandably erred in recording his statement as "The difference with the Americans is of course that they are generating two or three hulls from 14 ..." Perhaps he said or meant to say "... they are generating two of three hulls from 14 ..."

  In fact, the overall at-sea rate of the US Trident is 66%. Roughly 10% of the entire fleet is in refurbishment (one year out of 10) and the remainder is on a normal operating schedule (73% at-sea rate for operational SSBNs). The typical deployment schedule is at-sea for roughly 78 days, and in-port for 28. During the 28 day "refit" period (18-22 of these days may be in dry-dock) the crew that completed its at-sea operations works with the second crew to prepare the ship for its next 78-day second-crew tour.

  I do not know the corresponding numbers for Vanguard.

  Rear Admiral Mathews identified "things like cables" as components that age at similar rate whether the SSBN is operating or is in maintenance, but it is clear that many do not, among those most of those listed by Defence Minister as problematical for life extension: "replacement of some of the systems critical to submarine operations, such as external hydraulic systems, elements of the control systems (plane and the rudder), sonar systems, electrical systems (including the main battery) and refurbishment or replacement of elements of the nuclear propulsion system."

  So far as non-operational deployments are concerned, such as "training," these can and should be minimized and at the same time the quality of training and evaluation much improved by the aggressive use of simulators. A Vanguard simulator should have, of course, the same human interface as the submarine, but it would be a "virtual Vanguard" that responds to commands and manipulations as the real SSBN should, but can readily be put into conditions that would be impractical or dangerous for the real ship. Such a capable simulator is no minor matter, but it is of great value.

  I close by restating our judgment that the MoD has not communicated sufficient information for the Defence Committee to judge the merits of its case to commit to a renewal of the Vanguard fleet, and our recommendation that more work be done on the substance and cost of a 15-year life extension program, in preparation for an informed decision next year. It would be most helpful to the Committee's work (and to the MoD itself) to have an in-depth technical review of the issue by an outside expert panel.

 19 February 2007

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