Executive summary
Date(s) of inspection:
July 2025
Aim of inspection
To judge the adequacy of DRDL’s implementation of its arrangements made under LC 19 for construction of the 10 Dock caisson. LC 19 (Construction or installation of new plant) includes the requirement for the licensee to make and implement adequate arrangements to satisfy the requirements of the condition. ONR will sample evidence of DRDL’s implementation of its arrangements made under these conditions.
Subject(s) of inspection
- LC19 - Construction or installation of new plant - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
DRDL is undertaking an extensive upgrade of the 10 Dock facility to support Deep Maintenance Periods (DMPs) of Astute Class (A-Class) submarines. This includes significant modifications to the Water Retaining Boundary (WRB) including construction of a new caisson, which is being undertaken in advance of the more complex WRB upgrades. Whilst there is no formal regulatory hold point on commencement of the caisson construction, there is a future hold point on commencement of the WRB upgrades. This inspection judged the adequacy of DRDL's compliance with implementation of its arrangements for Licence Condition (LC) 19 for construction of the caisson including consideration of ill-conceit or execution of the works. Its purpose is gain assurance of DRDL's ability to implement the quality and safety case requirements for the water retaining boundary (WRB) and inform the future regulatory decision on implementation of the Pre-Construction Safety Report for construction for the reconstruction of 10 dock.
Conclusion
The inspection was undertaken and rated against published guidance on regulatory expectations, as described in ONR's technical inspection guides NS-INSP-GD-019 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 19 requirements.