Executive summary
Date(s) of inspection: January 2025
Aim of inspection
ONR Nuclear Safeguards Inspectors visited the EDF Sizewell B station on 14 and 15 January 2025 in order to conduct a nuclear safeguards compliance inspection. The purpose of this inspection was to seek evidence in support of EDF's compliance with The Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19).
ONR formed regulatory judgements and provided a rating in line with ONR’s inspection rating guidance of EDF's compliance against NSR19 Regulations 6, 7, 9, 10, 11, 12 and 18. To form effective regulatory judgements on EDF's compliance with the NSR19 Regulations listed, inspectors considered the ONR Guidance for the Assessment of Nuclear Material Accountancy, Control and Safeguards (ONMACS) and the expectations within. This inspection focussed particularly on Fundamental Safeguards Expectations (FSEs) 3, 6, 7, 8 and 9.
Subject(s) of inspection
- FSE 3 Competence Management - Rating: GREEN
- FSE 6 Measurement Programme and Control - Rating: GREEN
- FSE 7 Nuclear Material Tracking - Rating: AMBER
- FSE 8 Data Processing and Control - Rating: AMBER
- FSE 9 Material Balance - Rating: AMBER
- NSR19 Reg06 - Accountancy and control of qualifying nuclear material - Rating: AMBER
- NSR19 Reg07 - Accountancy and control plan - Rating: GREEN
- NSR19 Reg09 - Operation of an accountancy and control plan - Rating: GREEN
- NSR19 Reg10 - Operating records - Rating: AMBER
- NSR19 Reg11 - Accounting records - Rating: AMBER
- NSR19 Reg12 - Accounting reports - Rating: AMBER
- NSR19 Reg18 - Reporting of nuclear transformations - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
In accordance with the Office for Nuclear Regulation (ONR) Safeguards inspection and assessment plan 2024/25 for EDF, this inspection was performed to inspect EDF’s compliance with the requirements of the Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19).
This inspection sought to collect evidence of arrangements and their implementation to make judgements of compliance against the NSR19 Regulations 6, 7, 9, 10, 11, 12 and 18, and the ONR Nuclear Material Accountancy, Control, and Safeguards Assessment Principles (ONMACS) Fundamental Safeguards Expectations (FSEs) 3, 6, 7, 8 and 9.
The inspection targeted the operator’s arrangements and their implementation for qualifying nuclear material (QNM) accountancy and control, computer modelling for the generation of accountancy data, and competence management.
Based on the evidence sampled, plant walkdown and discussions I held with the key staff, I judge that EDF Sizewell B are implementing the arrangements described in their Accountancy and Control Plans (ACP) as required by NSR19 Regulations 7 and 9, and that the implementation of these arrangements are adequate to meet ONR expectations FSE 3 Competence Management and FSE 6 Measurement Programme and Control, and NSR19 Regulation 18 for the reporting of nuclear transformations. However, I identified significant shortfalls regarding the tracking, control and accountancy of non-fuel QNM, and significant shortfalls associated with Physical Inventory Taking (PIT) arrangements and records. I judge that these findings demonstrate significant shortfalls in compliance against NSR19 Regulations 6, 10, 11 and 12, and do not meet the expectations of FSEs 7, 8 and 9.
As a result of these shortfalls I raised two Level 3 Regulatory Issues. I raised a Regulatory Issue to conduct an extent of condition for unreported QNM across the EDF fleet to ensure the identification and accurate reporting of all QNM in line with the requirements of NSR19. I raised a Regulatory Issue to ensure adequate PIT arrangements are implemented at QSZB and QSZS and that an extent of condition report be conducted to understand whether this issue is present across the EDF fleet requiring a wider PIT arrangements review.
I raised Regulatory Advice against labelling of material and physical inventory verification procedures for an item of QNM.
I provided Regulatory Advice to implement quality assurance processes to ensure accountancy data is consistent between the nuclear material accountancy reports for a Material Balance Period (MBP) and identify the reason for any Material Unaccounted For (MUF).
Conclusion
Based on the sample inspected, I judge that EDF Sizewell B are implementing the arrangements described in their ACP and are compliant with NSR19 Regulations 7 and 9. I judge that EDF Sizewell B are implementing their arrangements for competence management and computer modelling for the generation of accountancy data in-line with regulatory expectations FSEs 3 and 6, and are compliant with NSR19 Regulation 18.
My findings against the sample inspected have identified significant shortfalls in compliance for the tracking, control and accountancy of non-fuel QNM, and PIT arrangements and records against NSR19 Regulations 6, 10, 11 and 12, and associated regulatory expectations FSEs 7, 8 and 9.
I have raised two Level 3 Regulatory Issues regarding the extent of condition for unreported QNM across the EDF fleet and the shortfalls in PIT arrangements.
Regulatory advice provided during this inspection will be followed up as part of routine regulation.
Upon consideration of the ONR guidance on inspection ratings and application of the EMM, I judge that a rating of AMBER (seek improvement) is appropriate and an Enforcement Letter will be produced.