Office for Nuclear Regulation

Harwell – Inspection ID: 52181

Executive summary

Date(s) of inspection:

  • August 2023

Aim of inspection

In accordance with the Office for Nuclear Regulation (ONR) Integrated Inspection Strategy (IIS) 2023/24 for Magnox Ltd. Harwell. ONR Safeguards conducts Safeguards compliance inspections at the Harwell site. One such intervention was performed to inspect the site’s compliance with the requirements of the Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19) in relation to implementation of the Accountancy and Control Plan (ACP). For this intervention, the Material Balance Area (MBA) known as QHR1 was selected, and the inspection planned as an accountancy and control plan focused compliance inspection.

The purpose of an ACP compliance inspection was to review the implementation of the operator’s procedures as described within the ACP. The purpose of the accountancy inspection element was to ensure that the arrangements and procedures described in the ACP that form the system of Nuclear Material Accountancy Control and Safeguards (NMACS) were being implemented effectively at the facility. The purpose of this inspection was to gain evidence and enable ONR inspectors to make judgements on Magnox Harwell’s compliance with regulations 6, 7, 8, 9, 10, 11, 12, 14, and 15 in NSR19.

Subject(s) of inspection

  • FSE 10 Quality Assurance and Control for NMACS – Rating: Green
  • FSE 5 Reliability, Resilience and Sustainability – Rating: Green
  • FSE 7 Nuclear Material Tracking – Rating: Green
  • FSE 8 Data Processing and Control – Rating: Green
  • NSR19 Reg06 – Accountancy and control of qualifying nuclear material – Rating: Green
  • NSR19 Reg07 – Accountancy and control plan – Rating: Green
  • NSR19 Reg08 – Replacement, amendment and revocation of accountancy and control plan – Rating: Green
  • NSR19 Reg09 – Operation of an accountancy and control plan – Rating: Green
  • NSR19 Reg10 – Operating records – Rating: Green
  • NSR19 Reg11 – Accounting records – Rating: Green
  • NSR19 Reg12 – Accounting reports – Rating: Green
  • NSR19 Reg14 – Inventory change report – Rating: Green
  • NSR19 Reg15 – Material balance report and physical inventory listing – Rating: Green

Key findings, inspector’s opinions and reasons for judgement made

1. I conducted an ACP inspection, focussing on the MBA QHR1 at the nuclear licensed site. The inspection comprised of discussions with staff, demonstration of accountancy systems, reviews of associated procedures, operating and accounting records and a plant walkdown.

2. The inspection targeted two components. First, the operator’s ACP, and the effective implementation of the associated procedures. Second the operator’s procedures for accounting for Qualifying Nuclear Material (QNM) and retained waste (RW). This involved a demonstration of the associated accountancy supported by these procedures. A demonstration of the nuclear material accountancy (ATOM) system and review of traceability from operator records to the associated accountancy reports was provided.

3. This intervention was performed in line with ONR’s guidance (as described in the relevant technical inspection and assessment guides, which can be found on ONR’s website (

4. I identified no shortfalls as part of the inspection and based on the sample I inspected; I judge Magnox Harwell has adequately implemented the following elements:
An accountancy and control program for both QNM and retained waste as described within the ACP.

A system to track qualifying nuclear material and retained waste within QHR1. Based on the discussions with relevant staff, review of associated procedures, and review of accountancy records I judge that Magnox Harwell are adequately tracking nuclear material within QHR1 and are implementing the arrangements described in their ACP as required by NSR19 Regulations 6, 7, 8, 9, 10, 11, 12, 14, and 15.

5. I provided a single piece of regulatory advice, but this did not represent a shortfall against NSR19 requiring a new regulatory issue.

6. I raised two observations in relation to (a) an appropriate challenge raised by staff on plant as part of the plant walkdown and (b) correction of a reference in a procedure.


1.    Based on the sample inspected, I judge that  Harwell are adequately implementing their arrangements for tracking nuclear material, including retained waste, in line with their corporate ACP. The implementation of these arrangements is supporting the accountancy and control of QNM in-line with regulatory expectations and are compliant with NSR19 Regulations 6, 7, 8, 9, 10, 11, 12, 14 and 15.

2.    I identified no regulatory shortfalls as part of the inspection.

3.    Upon consideration of the ONR guidance on inspection ratings, I judge that a rating of GREEN (no formal action) is appropriate.