Office for Nuclear Regulation

Rolls-Royce Submarines Limited’s (RRSL) – Inspection ID: 50449

Date(s) of inspection:

  • October 2022

Aim of inspection

This was a planned intervention to evaluate the adequacy of implementation of Rolls-Royce Submarines Limited’s (RRSL) arrangements for licence condition 22 (modification or experiment on existing plant) at the Raynesway nuclear licensed sites.  RRSL has made significant improvements in its LC22 arrangements (and implementation) since late 2020.  The previous LC22 inspection focused on the arrangements themselves and resulted in a GREEN rating, as such this intervention sought to ensure that the improvements made to the arrangements have been embedded and are being implemented.

The intervention was conducted on-site by the ONR nominated site inspector for the Raynesway nuclear licensed sites, utilising relevant good practice from ONR-INSP-GD-022 revision 7.

Subject(s) of inspection

  • LC22 – Modification or experiment on existing plant – Rating – Green

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

RRSL has continued to make improvements to the LC22 arrangements over the past two years, moving from AMBER ratings in 2019 and early 2021 to a GREEN rating in late 2021.  This inspection found that those improved arrangements are being adequately implemented, leading to a position where RRSL is now fully aware of the scope of change on the site, both in flight and planned, through the use of the Change Sentencing Board (CSB).  Submissions to the CSB have increased significantly since the update and briefing of the new arrangements and the CSB is providing a sufficient level of challenge and governance to the modification process.  Modification forms examined on the day were completed in line with RRSL’s arrangements and met my regulatory expectations.

RRSL has continued to reduce the number of longstanding (2+ years) modifications and the remaining ‘non-capital build’ modifications are due to be closed in early 2023.  RRSL has adopted a positive culture in driving through the improvements in this area.


Based on the sample inspected, I rate the LC22 intervention as GREEN – ‘No Formal Action’.  This rating is in line with the established ONR guidance.

  • “Relevant good practice generally met, or minor shortfalls identified, when compared with appropriate benchmarks.”
  • “No significant shortfalls identified in the delivery of safety, safeguards or security functions.”