Vigilant Afloat - Major Milestone in LOP(R)

A major and visible milestone has been achieved in the Long Overhaul Period (Refuel) [LOP(R)] on Vanguard class ballistic missile submarine (SSBN) HMS Vigilant with the successful completion of flood-up today (16 June) - the first time the submarine has been afloat in over two and a half years, since dry docking in November 2008. The LOP(R) is being undertaken by Babcock at Devonport Royal Dockyard. The successful achievement of flood-up signals completion of some 80 per cent of the work programme on HMS Vigilant. Refuelling - a critical element of the three and a half year LOP(R) which dictates the overall programme duration - was successfully completed in November last year. This is supported by a major revalidation of all reactor systems and replacement of major equipment such as the main coolant pumps, reactor pressure vessel head and reactor instrumentation suite, and a significant commissioning programme. In addition, the LOP(R) has seen a significant number of upgrades to the tactical and strategic weapons systems, as well as a vital and substantial overhaul of the propulsion system including main engines, 700KW motor generators, refurbishment of the tailshaft, plus major external represervation work, and upgrades to the accommodation and mess areas. Since completion of refuelling last autumn, the Vigilant LOP(R) team has been focused on commissioning submarine systems and reinstating the submarine structure to provide water-tight integrity assurance in readiness for flood-up, involving a step change in vessel condition and a substantial programme of work. This has included completion of trim, bilge and ballast systems testing and operational handover of emergency breathing, communications, flood alarms and fire fighting systems to ship's staff to support emergency response while afloat. Steam machinery trials in dry dock have also been successfully completed, providing an early operational test of the propulsion systems (except turning the main shaft) and demonstrating the quality of workmanship with very few defects. Babcock Project Manager Phil Smith comments: "The significance of this milestone is huge, not just in terms of the programme, but in bringing together so many diverse groups of workers in a common cause. The submarine crew also had a vital part to play in the lead up, taking operational ownership of a number of systems. To have successfully achieved flood-up is a major milestone and highly visible demonstration of the excellent progress being made. Loop fill (filling the primary reactor circuit) follows closely in July, and our reactor production teams and reactor test team are driving hard for this milestone." He adds: "The partnering agreement1 between Babcock and the MoD has without doubt contributed to this latest success - the fact that we strive together as one for the common goal at the coalface is key. This is a highly complex and challenging programme, and the joint project team is now firmly committed to meeting the remaining challenges and achieving the key programme milestones efficiently and effectively, to ensure successful delivery of the project within the agreed contract acceptance date next year, representing optimum value for money for the MoD and Royal Navy." Flood-up will now be followed by a focus on final completion through a programme of reactor system testing and commissioning, and its integration with the propulsion systems through a series of 'Cold and Hot' operations (CHops). This will culminate in Power Range Testing (PRT) at the end of this year, where the new core achieves criticality for the first time, generating 'nuclear steam' to prove the propulsion plant and supporting sub-systems. HMS Vigilant will then sail from Devonport for sea trials in 2012. Commenting on this key milestone, MoD Project Contract Manager Nick Febbrarro said: "An important requirement for the MOD is that HMS Vigilant is completed to the programme timescale or earlier. This very important milestone in the drive to meet this requirement marks the culmination of a comprehensive work package to return submarine systems and equipment back to service and in accordance with design intent. Completion of this milestone is testament to the application of a highly skilled workforce and the significant investment in time and resources by all stakeholders. During the commissioning phase we have worked in close co-operation with Babcock and the Ship's Company and are now in the best possible shape to take the project forward into the final phase of the LOP(R) including reactor commissioning." HMS Vigilant is the third Vanguard class submarine to undergo a LOP(R) at Devonport. The project represents five years of activity (including the planning phase) and over GBP300 million to return the submarine to the fleet capable of fulfilling her role well into the 21st century. The massive project will involve more than 2.2 million manhours and a total of 2,000 personnel.
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Source: Babcock International
Date: Jun 17, 2011