Office for Nuclear Regulation

Rolls-Royce Submarines Limited (RRSL) – Inspection ID: 52442

Executive summary

Date(s) of inspection:

  • September 2023

Aim of inspection

This was a planned inspection to form a judgement on the adequacy of implementation of RRSL’s revised Contact Shop safety case, ensuring it reduces risks ALARP, specifically with respect to criticality safety.  Relevant Licence Conditions were:

  • 10 – Training
  • 12 – Duly authorised and other suitably qualified and experience persons
  • 23 – Operating rules
  • 24 – Operating instructions
  • 26 – Control and supervision of operations

RRSL’s revised Contact Shop safety case was controlled by a modification proposal submitted to ONR for a derived power agreement.  However, in accordance with PR-01299, ONR chose to undertake this post implementation review, rather than permission the modification.  This was on the basis of minimal operator-facing change to administrative or engineering controls.

Subject(s) of inspection

  • LC10 – Training – Rating: Green
  • LC12 – Duly authorised and other suitably qualified and experienced persons – Rating: Green
  • LC23 – Operating rules – Rating: Green
  • LC24 – Operating instructions – Rating: Green
  • LC26 – Control and supervision of operations – Rating: Green

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

As a result of the intervention, including consideration of material received prior to the inspection, as well as that determined during the inspection itself, ONR made the following judgements/observations against the relevant Licence Conditions (LC), based on the sample inspected.

LC10 – Training – The training packs had been well considered, with the changes to the case briefed out to operators through a toolbox talk (enhanced for Duly Authorised Persons).  The wider training approach had been underpinned by suitable training needs analysis.  Operators spoken to demonstrated a good level of understanding of the revised case in their areas. Pockets of potential improvement were identified by ONR, including the number of operators still requiring training (though they were planned in).

LC12 – Duly authorised persons (DAP) – The DAP interviewed displayed a good level of knowledge despite only being fairly recently appointed.  The appointment process appeared robust.  DAP daily and weekly checklists are not version controlled which could lead to divergence from the safety case over time.

LC23 – Operating rules – Limits and conditions identified in the case had been appropriately implemented.  Operators displayed good knowledge in relation to the Operational Working Limits in their areas.  Opportunities for improvement linked to change control of operator aids/signage in relation to limits and conditions were identified.

LC24 – Operating instructions – Technical Instructions held electronically and available at/near the point of work.  Some hard copy work instructions were noted as not being in date or the latest version, some had handwritten additions, suggesting an opportunity to improve ‘controlled copy’ process.

LC26 – Control and supervision of operations – We considered that DAP control and supervision is adequate, with check sheets and log books completed appropriately, and the handover process described clearly.


Based on the sample inspected, which was limited to implementation of the contact shop revised safety case, I rate the relevant LCs (10, 12, 23, 24, & 26) 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.”