End in Sight for Vigilant

The Long Overhaul Period (Refuel) (LOP(R)) on HMS Vigilant – the third Vanguard class ballistic missile submarine (SSBN) refit and refuel to be undertaken by Babcock – is approaching the end of nearly three and a half years’ work at Devonport Royal Dockyard, following successful completion of a formal Pre-Sea Trials Inspection, which recognised the project’s ‘commendable performance’. 

A key feature of the over £300 million LOP(R), which has represented five years of activity including the planning phase, has been the successful implementation of new ways of working, designed to assure programme delivery, ensure product quality and maximise the submarine’s operational capability.  A ground-breaking contractual arrangement between Babcock and the MoD has supported close co-operation and joint working, greater transparency of information, focused attention on cost reduction while improving safety and quality standards, and incentivised achievement of the agreed schedule.

In addition to the new partnering approach, the LOP(R) has included a number of ‘firsts’, including the installation and commissioning of the Combined Oxygen Generation System, and a modification to the control rod drive mechanisms to further improve nuclear safety for the platform during maintenance periods.  Babcock has also undertaken structural survey work with a first-of-class use of leading-edge ultrasonic (phased array and time of flight diffraction) techniques to validate the hull for the submarine’s next commission.

Some 200 design alterations and additions (A&As) and class modifications have been incorporated in the LOP(R).  Significant changes have included an upgrade to the latest reactor core as used in Astute class submarines (fuelling the submarine for life), installation of improved chilled water plants and system, and a large number of upgrades to the tactical and strategic weapons systems, including sonar 2054 inboard replacement and subsequent integration.  Additionally, upgrades to the accommodation and mess areas have provided an opportunity to incorporate a state of the art entertainment system.

This major project has involved more than 2.3 million manhours, over 2,000 people, and more than 80 subcontracting companies.  Some 26,000 items of equipment have been removed from the submarine and overhauled.  More than 6,500 welds have been completed on board, of varying types from replacement of pressure hull plating to reactor primary circuit pipework.  32,000 litres of paint have been applied to the submarine, and some 400 systems have been tested by the Babcock commissioning teams.

HMS Vigilant arrived in Devonport in autumn 2008.  Refuelling was completed in November 2010 and flood-up in June 2011 after successful completion of steam machinery trials in dry dock.  Power Range Testing (PRT), where the new core achieves criticality for the first time, generating ‘nuclear steam’ to prove the propulsion plant and supporting sub-systems, is currently in progress.

Babcock project manager Phil Smith said: “The close working between Babcock and the MoD, Rolls-Royce and ship’s staff under a collaborative joint partnering team arrangement has been a key feature of this LOP(R), and has been central to the success of the project.  This has been a significant achievement by all, and is one to be proud of.  The team is now working hard to ensure the HMS Vigilant is ready to leave Devonport next month, capable of fulfilling her role well into the 21st century.” 

MoD Project Contract Manager Nick Febbrarro said: “As with any project of this size and complexity there have been many difficulties and challenges that have been overcome and significant project risks to manage.  The success that this LOP(R) has enjoyed is due to the close collaboration of many agencies and contractors, but particularly the joint project ethos that is dominant between MoD, Babcock, Rolls Royce and the Ship’s Company.”

HMS Vigilant will sail from Devonport next month for sea trials before officially returning to the fleet.  Babcock and MoD will be providing on-going support to the post-LOP(R) trials at sea and alongside at Faslane.

Source: Babcock International
Date: Feb 23, 2012