Date(s) of inspection:
- January 2023
Aim of inspection
System based inspections (SBIs) are an essential element of ONR’s overall intervention on a nuclear site and consist of a series of inspections which are intended to establish that the basic elements of a site/facility safety case as implemented in Safety Systems, Structures and Components are fit for purpose, and that they will fulfil their safety functional requirements.
This System Based Inspection:
To determine whether the safety systems, structures and components associated with the provision of CO2 Processing and Blowdown (including Bypass Gas Plant, Auxiliary Boilers and O2/COS and Injection) and CO2 Storage and Distribution and associated support systems including:
- Tanks + Lines – Storage limits / fire protection / extreme weather protection / Corrosion
- KPIs and availability
- Adequacy of implementation of the licensee’s arrangements.
can adequately fulfil their safety duties (safety functional requirements), in line with claims made within the safety case.
Subject(s) of inspection
- LC 10 – Training – Rating: GREEN
- LC 23 – Operating rules – Rating: GREEN
- LC 24 – Operating instructions – Rating: GREEN
- LC 27 – Safety mechanisms, devices and circuits – Rating: GREEN
- LC 28 – Examination, inspection, maintenance and testing – Rating: GREEN
- LC 34 – Leakage and escape of radioactive material and radioactive waste – Rating: GREEN
- Overall Inspection Rating – Rating: GREEN
Key findings, inspector’s opinions and reasons for judgement made
I examined evidence of the training undertaken by the individuals and was able to gain confidence that all the individuals sampled were suitably qualified and experienced for the sample activities examined.
I confirmed that verification of the Site Safety Report requirements were incorporated in the surveillance checks identified through compliance with relevant Technical Specifications. In addition, the requirements were noted in the System Handover Document.
I confirmed through examination of ‘Check List for per shift, per day and per week TS Surveillances’ (PIOI 92300/Z043), which the centre desk engineer performs as part of the TS surveillances, detailed the checks as defined in the Technical Specifications, thus confirming the requirements of the Site Safety Report were being observed. In addition, I confirmed that CO2 stock levels were checked and confirmed through completion of daily log.
I identified a minor shortfall in that the continuous use procedure (PIOI 92300/Z043, Check List for per shift, per day and per week TS Surveillances) was being used as reference use, and have raised a level 4 regulatory issue in view of this (RI11255).
Operability/Availability of Valve 900/901 is tested however, weakness in demonstration of adequacy of maintenance regime was identified. In view of this a Level 4 Regulatory issue was raised.
I judged the sampled Work Instructions for each of the sampled maintenance activities were adequately completed (annotated, signed and dated)
I judged that the licensees discharge monitoring spreadsheet adequately enabled adequate trending and control of discharges from the site
Site Licence Condition 10 –Training – ONR Inspection Rating Green (No Formal Action):
I am content that the arrangements for LC10 are adequate and implemented appropriately in line with the licensee’s arrangements. Based on the evidence sampled during this inspection, I judge an inspection rating of Green (no formal action) is appropriate for LC 10.
Site Licence Condition 23 – Operating Rules – ONR Inspection Rating Green (No Formal Action):
Overall, I judged that a clear line of sign was evident from SSR to TSs and that the requirements of the SSC were appropriately being observed. I therefore judged that the LC23 aspects of the SBI to be adequate. Based on the evidence sampled during this inspection, I judge an inspection rating of Green (no formal action) is appropriate for LC 23.
Site Licence Condition 24 – Operating Instructions – ONR Inspection Rating Green (No Formal Action):
Overall, from my sample I judged that the licensee’s operations effecting safety were carried out in accordance with written instructions. I identified a minor shortfall in that a continuous use procedure (PIOI 92300/Z043) was being used as reference use, and have raised a level 4 regulatory issue RI11255 to influence improvements in PQU&A for TS surveillance checks, and to examine extent of condition. I therefore judged overall that the LC24 aspects of the SBI to be adequate, subject to closure of RI 11255. Based on the evidence sampled during this inspection, I judge an inspection rating of Green (no formal action) is appropriate for LC 24.
Site Licence Condition 27 – Safety Mechanism Devices and Circuits – ONR Inspection Rating Green (No Formal Action):
Although I identified a minor shortfall in compliance relating to TS 5.2.1 I judge that the surveillance requirements of TS 5.2.1 were complied, ensuring that the SSR is complied with and that suitable and sufficient safety mechanisms, devices and circuits are properly connected and in good working order.
From this, I was satisfied that these aspects are sufficient for the purposes of LC27 and therefore consider a green rating (no formal action) is appropriate for LC 27.
Site Licence Condition 28 – Examination, Inspection, Maintenance and Testing – ONR Inspection Rating Green (No Formal Action):
Based on the above and together with the general visible condition of the plant inspected during my plant walkdown, I was satisfied that adequate examination, maintenance, inspection, and testing had been carried out in line with maintenance schedule requirements. I consider that the Level 4 issue already raised would capture the shortfall identified as part of this LC28 Inspection. Therefore, I judge an IIS rating of green is appropriate for LC28.
Site Licence Condition 34 – Leakage and Escape of Radioactive Material and Radioactive Waste – ONR Inspection Rating Green (No Formal Action):
Based on the above, I was satisfied that adequate measures have been taken to prevent the leakage and escape of radioactive material from the CO2 storage and distribution system.
Therefore, I judge an IIS rating of green is appropriate for LC34.