Executive summary
Date(s) of inspection: September 2024
Aim of inspection
In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, each year ONR performs a series of planned inspections to seek assurance of compliance against selected licence conditions, targeted at those facilities with significant importance to nuclear safety. One such inspection was undertaken at Special Nuclear Materials Value Stream (SNM) South facilities within the Sellafield site in West Cumbria to sample evidence of implementation of Sellafield Limited's arrangements for compliance with Licence Condition (LC) 23 (Operating rules), 27 (Safety mechanisms, devices and circuits), 28 (Examination, inspection, maintenance and testing) and 34 (Leakage and escape of radioactive material and radioactive waste) specifically to SNM South Finishing Line 6 (FL6) and Thermal Oxide Reprocessing Plant (THORP) Product Store (TPS) ventilation systems, in order to inform a regulatory judgement regarding the licensee’s compliance with its legal duties under the nuclear site licence.
Subject(s) of inspection
- LC23 - Operating rules - Rating: Green
- LC27 - Safety mechanisms, devices and circuits - Rating: Green
- LC28 - Examination, inspection, maintenance and testing - Rating: Green
- LC34 - Leakage and escape of radioactive material and radioactive waste - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
The inspection was undertaken between 4 and 5 September 2024 by the Special Nuclear Materials (SNM) site inspector and supported by one mechanical engineering specialist inspector and one developing mechanical engineering inspector.
The inspection involved a planning phase and a site visit, which comprised discussions with Sellafield Limited personnel, a review of a targeted sample of Sellafield Limited’s documentation and a Finishing Line 6 (FL6) and Thermal Oxide Reprocessing Plant (THORP) Product Store (TPS) ventilation systems plant walkdown.
From a mixture of sampling records, discussions with Sellafield Limited personnel and a plant visit, I concluded the following:
No significant matters were identified that required immediate regulatory attention.
For LC23, I was satisfied that Sellafield Limited have adequately implemented the safety case limits and conditions, as specified within the current safety case, in relation to FL6 and TPS ventilation systems.
For LC27, I was satisfied that key Safety Mechanisms, Devices and Circuits (SMDC) had been identified in the safety case, could be located on plant and were properly connected and in good working order or good condition to deliver the safety function. One Level 4 (i.e. lowest level) regulatory issue has been raised to allow ONR to monitor progress in addressing the identified minor shortfall relevant to plant labelling of SMDSs (see RI-12211).
For LC28, I was satisfied that examination, inspection, maintenance and testing was being undertaken in an appropriate and timely manner.
For LC34, I was satisfied with the SMDSs in place, including their maintenance, in demonstrating compliance against leakage and escape of radioactive material and waste.
Regulatory advice on housekeeping was also provided.
Conclusion
No matters were identified as requiring immediate regulatory attention.
Based on the evidence sampled at the time of the inspection, I found that, on balance, SNM South is broadly compliant with the licensee’s corporate arrangements for LCs 23, 27, 28 and 34 specifically to FL6 and TPS ventilation systems. I therefore judge that SNM South has adequately implemented the licensee’s corporate arrangements made for compliance with the Nuclear Site Licence, with one minor shortfall identified in relation to LC27.
Taking all of the above into account, and noting the ONR guidance on inspection ratings, it is my opinion that, on balance, an inspection rating of Green (i.e. no formal action) for each of Licence Conditions 23, 27, 28 and 34 is appropriate.
One Level 4 (i.e. lowest level) regulatory issue has been raised to allow ONR to monitor progress in addressing the identified minor shortfall relevant to plant labelling of SMDSs.