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Devonport Royal Dockyard - Inspection ID: 52839

Executive summary

Date(s) of inspection:

  • February 2024

Aim of inspection

To judge the adequacy of DRDL’s implementation of its arrangements made under Licence Condition (LC) 28 for readiness to commence Deep Maintenance Periods (DMP) for Vanguard class boats in 9 Dock and Base Maintenance Periods (BMP) for Astute Class boats in 15 Dock. LC 28 (Examination, inspection, maintenance and testing) includes the requirement for licensees to make and implement adequate arrangements to satisfy the requirements of the condition.

Subject(s) of inspection

  • LC28 - Examination, inspection, maintenance and testing - Rating: Green

Key findings, inspector's opinions and reasons for judgement made

The 9 and 15 Dock facilities on the Devonport Royal Dockyard site are currently subject to maintenance, refurbishment and upgrade works in preparation for readiness to commence Vanguard Deep Maintenance Periods (VDMP) and Astute Base Maintenance Periods (ABMP) respectively. The outages include civil engineering examination, maintenance, inspection and testing (EIM&T) and repair/upgrade works. Whilst there is no formal regulatory hold point on these engineering works there is a hold point on implementation of the new plant safety cases (PSCs) to commence VDMP and ABMP. This inspection judged the adequacy of Devonport Royal Dockyard Ltd's (DRDL) compliance with implementation of its EIM&T arrangements for Licence Condition (LC) 28 and therefore plant readiness to commence VDMP and ABMP in 9 and 15 Docks respectively. Its purpose was to gain assurance of DRDL's ability to implement the quality and safety case requirements for these works and inform the future regulatory decision on implementation of the PSCs.

The inspection was undertaken and rated against published guidance on regulatory expectations, as described in ONR's technical inspection guides NS-INSP-GD-028 and ONR-INSP-GD-064. Based on the evidence sampled at the time of the intervention against DRDL's arrangements and documentation, and regulatory guidance ONR judged that DRDL demonstrated adequate compliance with LC 28.


Based on the findings of the intervention, ONR considers that DRDL has implemented adequately its arrangements for compliance with LC 28, specifically that EMIT was carried out:

  • by suitably qualified and experienced persons; 
  • in accordance with schemes laid down in writing;
  • within the intervals specified in the plant maintenance schedule; 
  • under the control and supervision of a suitably qualified and experienced person appointed by the licensee for that purpose.
  • a signed and dated report of every completed EIM&T has been done.

It is therefore judged that an inspection rating of Green (No formal action) is merited, in accordance with ONR Guide ONR-INSP-GD-064, where relevant good practice was met when compared with appropriate benchmarks; legal duties were complied with; and, no safety shortfalls were identified in the delivery of safety functions.