Office for Nuclear Regulation

Devonshire Dock Complex (Barrow) – Inspection ID: 52441

Executive summary

Date(s) of inspection:

June 2023

Aim of inspection

This was a planned intervention to evaluate the adequacy of the implementation arrangements for licence condition 22 (modification or experiment on existing plant) at BAE Systems Marine Limited (BAESML). BAESML undertakes changes in key nuclear safety case elements as the build stages of the submarines progress; correct configuration control through appropriate LC22 arrangements is important in ensuring nuclear safety is maintained.

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

Subject(s) of inspection

  • LC 22 – Modification or experiment on existing plant – Rating: GREEN

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

Based upon my sample, I judge that BAESML has a robust process in place for the categorisation and approval of site modifications, though its arrangements remain complex. BAESML has not been able to progress the update/simplification of the arrangements as quickly as hoped, however it has now engaged external resource to address this. In the meantime, BAESML continues to pursue practical efficiency improvements in the LC22 process, and these should be integrated into the arrangements as part of their expected update.

I do not have any significant concerns with the number of open Site Design Change Applications (SDCA), though I note that the number over three years old has increased by a third since the last inspection, and over a third of open applications are awaiting documentation to be closed out. I therefore encouraged BAESML to remain focused on the timely closeout of applications.

A sample of three completed SDCAs was taken, with no significant issues found, however I observed opportunities for improvement across all three forms in relation to the rigour used to complete the form. None of the findings in the inspection presented an immediate or direct risk to nuclear safety.


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.”

None of the findings in the inspection presented an immediate or direct risk to nuclear safety.