Office for Nuclear Regulation

Rolls Royce Submarines Limited (RRSL) – Inspection ID: 50448

Executive summary

Date(s) of inspection:

  • October 2022

Aim of inspection

This was a planned intervention to evaluate the adequacy of Rolls-Royce Submarines Limited’s (RRSL) arrangements for licence condition 7 (Incidents on the site) at the Raynesway nuclear licensed sites.  RRSL has made significant improvements in its LC7 arrangements (and implementation) since late 2020; this intervention sought to gather sufficient evidence to close out the extant regulatory issue (R-10444) on the topic.

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-007 revision 6.1.  The intervention was focused on the three areas captured by the extant regulatory issue (10444); i.e. implementation of effectiveness reviews, implementation of proactive trending, and timeliness of investigation delivery.

Subject(s) of inspection

  • LC7 – Incidents on the site – Rating: Green

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

The LC7 arrangements have been improved significantly over the past two years, and I consider that they meet regulatory expectations.  In that period, RRSL has shown a positive response to the challenge presented by ONR with regard to the shortfalls in its arrangements.

Whilst effectiveness reviews are not yet conducted on a routine basis (as they are generally undertaken approximately six months after all other actions are closed), the process is embedded appropriately into the arrangements along with a clear expectation of how they will be conducted (i.e. goals defined well in advance of the review), and the software side for implementation is set up to accommodate the reviews when they take place.  This process will been examined in a future LC7 compliance inspection.

Investigation timeliness has improved significantly, with only five of the lowest level investigations outstanding, the oldest being approximately two months old. The quality of the investigations and the effectiveness of the associated actions are being maintained.  The latest investigation report received by ONR was open and self-critical and identified a useful set of recommendations and actions that ONR used as the basis for related enforcement action.

Software-side improvements enabling proactive trending are now in place and were demonstrated.  More time is required to build up a sufficient quantity of data to allow effective interpretation of the data; again this will be examined in a future LC7 compliance inspection.


Based on the sample inspected, I rate the LC7 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.”

Sufficient evidence has been gained to allow closure of RI-10444.