Office for Nuclear Regulation

Devonshire Dock Complex (Barrow) – Inspection ID: 52443

Executive summary

Date(s) of inspection:

  • August 2023

Aim of inspection

This was a planned inspection to evaluate the adequacy of BAE Systems Marine Limited’s (BAESML) arrangements for Licence Condition (LC) 26 (Control and Supervision of Operations) and their implementation, with a particular focus on the control of work on energised systems, utilising the “Ripout” process.  This inspection was informed by a small number of events that have occurred on energised systems over the past year.

The intervention was conducted on-site by the ONR nominated site inspector for BAESML, as a joint inspection with the Defence Nuclear Safety Regulator.  In determining LC26 adequacy, relevant good practice from ONR-INSP-GD-026 revision 6 was used.

Subject(s) of inspection

  • LC26 – Control and supervision of operations – Rating: Green

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

Although the Ripout process was demonstrably well understood by all Test & Commissioning personnel spoken to, I found that the arrangements do not lend themselves to an easy understanding of the process, and I consider that a review of them would provide a benefit to the organisation by capturing corporate knowledge efficiently.

A recent Independent Nuclear Assurance (INA) surveillance on control of work identified a number of observations/recommendations, notably around risk assessment deployment/understanding, effectiveness of pre job briefs and a lack of dedicated team leaders on shift.  This aspect of the intervention suggests potential issues with control of work exist more widely, and BAESML should ensure that INAs findings are addressed in a timely manner.

A walkdown of a randomly selected Ripout aboard Agamemnon (Astute boat 6), revealed no issues with labelling or valve positioning, and the accompanying Senior Commissioning Engineer demonstrated an excellent working knowledge of the Ripout process.

I reviewed two investigation reports, relating to potential failures in the Ripout process.  I considered that one investigation (noting it was still in process) had not included the full circumstances of the event within its scope, and recommended that this was addressed. The findings in that investigation report again suggested potential issues with control of work exist more widely.  The other investigation captured suitable learning, which when implemented, should prevent a reoccurrence.

Future improvements in the Ripout process were discussed and were viewed as positive steps.

I consider a further LC26 control of work compliance inspection focusing on the workface implementation of work planning and setting to work within the Devonshire Dock Hall is necessary.


Based on the sample inspected (focused on the Ripout process), I rate the LC26 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.”

However, I note underlying issues with BAESML’s general control of work (evidenced by the INA surveillance findings and the preliminary findings of the level 1 investigation into the removal of the accumulator), which suggest a further LC26 control of work compliance inspection focusing on the workface implementation of work planning and setting to work within the Devonshire Dock Hall is necessary.