Date(s) of inspection:
- November 2022
Aim of inspection
The purpose of this inspection is to confirm that BAESML’s identification of safety mechanisms, devices and circuits (SMDCs) meets regulatory expectations. The regulators have made observations in previous system-based and operational readiness inspections regarding the identification of SMDCs in BAESML’s facility safety cases, in particular that not all items meeting the definition of a SMDC had been identified as such in the safety case. The aim of the inspection is to give the regulators confidence that BAESML has made improvements to the process for identifying SMDCs and that there is evidence that this is now being implemented appropriately. Compliance will be judged against ONR’s Technical Inspection Guide for LC27.
Subject(s) of inspection
- LC27 – Safety mechanisms, devices and circuits – Rating: Green
Key findings, inspector’s opinions and reasons for judgement made
I carried out an inspection of BAESML’s arrangements for compliance with LC 27 Safety Mechanism, Devices and Circuits (SMDCs). The focus was on the identification and implementation of SMDCs in the site safety case documentation. The inspection was carried out jointly with the Defence Nuclear Safety Regulator.
I considered BAESML’s processes and guidance for the identification of SMDCs and sought evidence that these had been adequately implemented in a recently completed site safety case.
I found that there was a clear definition of an SMDC and that personnel had a sound understanding of what this meant in practice. I saw evidence that BAESML is now applying a systematic process to identify SMDCs in its site safety cases and that this is being reflected in documents which implement the safety case, such as operating instructions. This addresses a key observation from previous inspections.
There is further work required to ensure that the identification of systems as SMDCs is fully reflected in maintenance procedures. However from the evidence sampled I was satisfied that there are adequate controls in place to ensure that the identified SMDCs are connected and in good working order.
There is still work to do to apply the process across all of the site safety cases, but I am satisfied that there is a programme to complete this as safety cases become ‘live’ to support the rolling programme of nuclear activities.
Overall, I was satisfied that BAESML has in place, and is following, an adequate process for identifying SMDCs in its site safety cases and that from my sample the requirements for SMDCs are being implemented. I rated the inspection as Green (no formal action).
I provided advice/observations on four aspects which BAESML should consider as potential improvements/clarifications to its arrangements. I was content for these to be progressed by BAESML alongside its own learning.
From evidence of the identification and implementation of SMDCs in a recent safety case, I considered that BAESML has made tangible progress in this area since previous inspections.
I was satisfied that BAESML had a clear definition of what an SMDC is, which was broadly consistent with that in ONR’s guidance to inspectors. Personnel had a sound understanding of what this meant in practice. The supporting documentation for a recent safety case demonstrated to me that, using the definition, there was a systematic process for identifying SMDCs. Whilst I consider there are areas that would benefit from further clarity, I am content that BAESML will take learning from the initial application of its process and consider further improvements as required.
Overall, I saw sufficient evidence of the ‘golden thread’ which links the identified SMDCs, through the site safety case into the documents which implement the safety case. BAESML recognises the need for further improvements, for example for SMDC requirements to be explicitly reflected in maintenance schedules. However, for the safety case considered in my sample, my judgement is that there are adequate controls in place to ensure that the identified SMDCs are connected and in good working order.
Overall, my judgement was that BAESML has in place, and is following, an adequate process for identifying SMDCs in its site safety cases and that from my sample the requirements for SMDCs are being implemented. I rated the inspection as Green (no formal action).
There is still work to do complete the process across all of the site safety cases, but I am satisfied that there is a programme to complete this as safety cases become ‘live’ to support future nuclear activities.