Office for Nuclear Regulation

Nuclear Fuel Production Plant Raynesway – Inspection ID: 52447

Date(s) of inspection

  • November 2023

Executive summary

Aim of inspection

In compliance with licence condition 11 (emergency arrangements), clause 5, Rolls-Royce Submarines Limited (RRSL) undertakes an emergency arrangements demonstration exercise on an annual basis.  This was a planned intervention to evaluate the adequacy of implementation of RRSL’s LC11 arrangements through observation of an end-to-end test, DERVENTIO II.

Subject(s) of inspection

  • LC11 – Emergency arrangements – Rating: Green

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

A team of five ONR inspectors observed RRSL’s emergency demonstration exercise ‘DERVENTIO II’, making observations in the Emergency Control Centre (tactical), Bronze Command (operational), contact muster area, and technical cell, as well as observations of the deployed teams.

Based on ONR’s observations of the Level 1 aspects of the demonstration exercise on the day, the principal learning point for RRSL is in ensuring that the emergency services can be deployed quickly onto the site in the event that they are required.  In my opinion, the length of time (approximately 100 minutes) that it took to rescue the individual involved in the simulated road traffic collision would have presented a significant challenge to the safety and welfare of that individual.  That issue aside, the remainder of the demonstration was delivered well.  Command and control dynamics in both silver and bronze commands were positive, as was the performance of the deployed teams and the decontamination and casualty handling aspects of the exercise.

ONR sent a letter to RRSL following the exercise with detailed observations from all aspects of the exercise to aid in RRSL’s continuous improvement.


I judge that this was an adequate demonstration of RRSL’s emergency arrangements, and therefore rate the 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.”

I have raised a level 4 regulatory issue (RI-11823) that aims to ensure that RRSL engages fully with the emergency services to provide adequate information about the site (including facilities, hazards and their context) to all responding personnel,  and to develop an agreed briefing structure that will lead to the prompt deployment of those personnel on site.  This issue has been discussed and agreed with RRSL’s Resilience Manager.