- Site: Hunterston B
- IR number: 20-051
- Date: October 2020
- LC numbers: 10, 23, 24, 27, 28, 34
Executive summary
Purpose of Intervention
The purpose of this intervention was to undertake a planned Licence Condition (LC) System Based Inspection (SBI) on the fuel route at EDF Energy Nuclear Generation Limited’s (NGL) Hunterston B (HNB) Power Station in preparation for end-of-generation (EoG), in line with the inspection programme contained in ONR’s Operational Facilities Division Intervention Strategy for 2020-21.
Interventions Carried Out by ONR
This SBI covered the HNB back-end fuel route (from removal of irradiated nuclear fuel from the reactor through to its preparation for dispatch off-site, as well as managing waste arising). This inspection covered the charge machine, the irradiated fuel dismantling facility, the pond and flask area, the fuel pond (civil structure), the pond water treatment plant and the debris voids.
This inspection was undertaken by ONR’s HNB site inspector, an end-of-generation project inspector and specialist inspectors from: fuel and core; mechanical engineering, and control & instrumentation.
During this intervention we examined HNB’s compliance with the following nuclear site Licence Conditions (LC), which are all applicable provisions of the Energy Act 2013:
- LC10 – Training;
- LC23 – Operating Rules;
- LC24 – Operating Instructions;
- LC27 – Safety Mechanisms, Devices and Circuits;
- LC28 – Examination, Inspection, Maintenance, and Testing; and
- LC34 – Leakage and Escape of Radioactive Materials and Radioactive Waste.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Explanation of Judgement if Safety System Not Judged to be Adequate
The Inspection identified several shortfalls in compliance with LC23 across the range of facilities inspected. The technical and environmental specifications did not, in some areas, adequately specify the limits and conditions of operation reflecting those specified in the safety case. There were also shortfalls in the living safety case document which did not accurately reflect the plant configuration.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
- LC 10 (Training) – We examined the training records of several personnel involved in operations and maintenance activities associated with the back-end fuel route. We judged that EDF NGL’s training arrangements for the personnel undertaking these activities had been implemented appropriately. We therefore assigned a rating of Green (no formal action) for LC10 compliance.
- LC 23 (Operating Rules) – The technical and environmental specifications did not, in some areas, adequately specify the limits and conditions of operation reflecting those specified in the safety case. We also noted shortfalls in the living safety case documentation which did not accurately reflect the plant configuration. We therefore assigned a rating of Amber (seek improvement) for LC23.
- LC 24 (Operating Instructions) – We examined a number of operating instructions associated with the back-end fuel route. We found some minor issues with the sampled instructions. Despite this we judged these documents to be of an adequate standard. Some procedural use and adherence issues were also identified, which we will follow up with the Licensee. Overall, we have assigned a rating of Green (no formal action) for LC24.
- LC 27 (Safety Mechanisms, Devices and Circuits) – Based on the areas sampled we were satisfied that suitable and sufficient safety mechanisms, devices and circuits are connected and in working order to meet the requirements of the safety case. Therefore, we have assigned a rating of Green (no formal action) for LC27.
- LC 28 (Examination, Inspection, Maintenance and Testing) – We examined a number of maintenance schedule items and work order cards. We confirmed that maintenance was being undertaken in line with the intervals as specified in the maintenance schedule. We identified several shortfalls, mainly related to the completion of work order cards. We did not consider these shortfalls posed any risk to nuclear safety as it was evident that the maintenance had been undertaken satisfactorily. We assigned a rating of Green (no formal action) for LC28 and we will follow up on the procedure use and adherence aspects for the completion of work order cards.
- LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) – Based on the records sampled and discussions held, we were satisfied that adequate arrangements had been implemented to ensure that radioactive material and radioactive waste is adequately contained, and that leaks would be detected. On that basis, a rating of Green (no formal action) against LC34 has been assigned.
Conclusion of Intervention
The back-end fuel route inspection was wide ranging and involved multiple parallel sessions and a range of ONR specialisms. HNB staff provided access to information and facilities in a timely fashion and supported the smooth running of the inspection. It was considered HNB staff were knowledgeable and general housekeeping standards on site were good.
Overall, we judged that the back-end fuel route systems were in line with the requirements of the safety case and were able to perform their safety functions as required. From the evidence sampled during this inspection, we did identify that, in some areas, the fuel route plant and systems did not meet regulatory expectations relating to LC23 implementation. As a result, ONR will write to the Licensee to seek improvement regarding LC23 compliance.
In addition, the procedural use and adherence shortfalls, identified under LC24 and LC28, will be followed up as part of regulatory interactions on the licensee’s development of a “Fuel Route Excellence” plan.