Executive summary
Date(s) of inspection:
- September 2023
Aim of inspection
The aim of the Torness Boiler Feed System (BFS) system based inspection (SBI) was to confirm that the:
BFS is able to meet the nuclear safety functional requirements defined in the station’s safety case.
BFS arrangements in relation to the following Licence Conditions (LCs), which are applicable provisions of the Energy Act 2013, are being correctly implemented:
- LC10: Training.
- LC23: Operating Rules.
- LC24: Operating Instructions.
- LC27: Safety Mechanisms, Devices and Circuits (SMDCs).
- LC28: Examination, Inspection, Maintenance and Testing (EIMT).
- LC34: Leakage and Escape of Radioactive Material and Radioactive Waste.
This was achieved through a sample based inspection of associated arrangements, a plant walkdown, and discussions with various stakeholders, (e.g. operators, maintainers, engineers, and training administrators).
This inspection was performed in line with ONR’s guidance requirements, which are described in our technical inspection guides (TIGs). These can be found at: www.onr.org.uk/operational/tech_insp_guides/index.htm.
Subject(s) of inspection
- LC10 – Training – Rating: Green
- LC23 – Operating rules – Rating: Green
- LC24 – Operating instructions – 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
- Overall Inspection Rating – Rating: Green
Key findings, inspector’s opinions and reasons for judgement made
The key findings of our SBI of the Torness BFS are:
LC 10 – Training: We examined the training records of a number of personnel involved with the oversight, maintenance, and operation of the BFS and judged that they were suitably qualified and experienced personnel (SQEP). We also reviewed BFS training material and found its scope to be appropriate and its contents to be informative. We also provided advice that was intended to enhance the effectiveness of system handover documents (SHDs). We therefore assigned an inspection rating of Green (no formal action) for LC 10.
LC 23 – Operating rules: We reviewed the technical specifications (Tech Specs) and corresponding commentaries that are associated with the BFS and discussed their application with a senior operator. As a result, we judged that the Tech Specs and commentaries were clear and logical, and straightforward for operations personnel to follow. We also confirmed that the associated surveillance requirements were being undertaken as required. We therefore judged that compliance was being achieved with the BFS operating rules specified in the safety case. We therefore assigned an inspection rating of Green (no formal action) for LC 23.
LC 24 – Operating instructions: We examined the main station operating instructions (SOIs) associated with the BFS and discussed their application with a senior operator. As a result, we judged that adequate operating instructions were in place to support BFS operations. We therefore assigned an inspection rating of Green (no formal action) for LC 24.
LC 27 – SMDCs: We reviewed several engineering, operating, and maintenance documents, undertook a plant walkdown and spoke to a number of stakeholders. As a result, we considered that the BFS was correctly connected and in working order. We also considered that BFS configuration was being adequately controlled and that sufficient numbers of spares were available. We also provided advice that was intended to ensure that the effectiveness of established arrangements was maintained and that the rationale behind work deferral decisions is adequately recorded. We therefore assigned an inspection rating of Green (no formal action) for LC 27.
LC 28 – EIMT: We reviewed a number of BFS maintenance work instructions (WIs), and associated work order cards (WOCs) and checksheets. As a result, we considered that, on the whole, the associated maintenance tasks had been adequately defined and that the WOCs and associated checksheets had been appropriately completed. We did identify a small number of areas where improvements could be made, which we raised with Torness, and will follow them up as part of normal regulatory business. We also found that each of the sampled maintenance tasks had been completed in line with the periodicity specified in the maintenance schedule. During the plant walkdown we identified shortfalls in the control of foreign material exclusion (FME) and redundant cable management within the make-up water treatment plant (MUWTP) control room programmable logic controller (PLC) cubicle and raised a level 4 (L4) Regulatory Issue (RI) (RI-11732) to ensure that these shortfalls are adequately addressed. It should be noted that we did not consider that the shortfalls presented an immediate or significant risk to nuclear safety. We therefore judged that the BFS was being adequately examined, inspected, maintained, and tested. We therefore assigned an inspection rating of Green (no formal action) for LC 28.
LC 34 – Leakage and escape of radioactive material and radioactive waste: It should be noted that we chose to include LC 34 within the scope of the SBI on the basis that there was a potential for reactor gas to enter the BFS via a boiler tube breach. Based on discussions with key stakeholders we considered that adequate arrangements were in place to identify and rectify any such leaks. We therefore assigned an inspection rating of Green (no formal action) for LC 28.
Conclusion
From the evidence sampled during this SBI against LC 10, 23, 24, 27, 28 and 34, we judged that the BFS was able to fulfil its safety duties (safety functional requirements) in line with the safety case.
There are no findings from this intervention that could significantly undermine nuclear safety at Torness. At present, no additional regulatory action is needed over and above the planned interventions at Torness, which will continue as planned.
We therefore judged the overall inspection rating for the SBI to be Green (no formal action).