Planned inspection of Dungeness B power station
- Site: Dungeness B
- IR number: 17-110
- Date: October 2017
- LC numbers: 10, 23, 24, 27, 28
Purpose of Intervention
This was a planned inspection of EDF Energy Nuclear Generation Ltd's (NGL's) Dungeness B power station, undertaken as part of the planned intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR).
The work was carried out in-line with the planned inspection programme contained in the Dungeness B Integrated Intervention Strategy (IIS).
Interventions Carried Out by ONR
During this intervention, the following key activities were undertaken:
- System based inspection (SBI) of the electrical systems, including Transformers, Grid Systems and Main Electrical System.
- Routine engagement with the Station's Independent Nuclear Assurance team.
- Attendance at the Dungeness Site Stakeholder Group.
- Routine engagement on station performance and events.
I the nominated site inspector was supported by two ONR electrical specialist inspectors in undertaking an SBI on the Dungeness B Electrical - Transformers, Grid Systems and Main Electrical System.
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
From our inspection, we judged that the electrical systems, including Transformers, Grid Systems and Main Electrical System can fulfil the safety functional requirements of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the SBI of the Electrical systems, including Transformers, Grid Systems and Main Electrical System, we concluded that:
- LC 10 (Training) - We examined the training records of a number of personnel involved in operations and maintenance activities associated with the electrical systems. We judged that the personnel undertaking these operations and maintenance activities were suitably qualified and experienced. We therefore assigned a rating of Green (no formal action) for LC 10 compliance.
- LC 23 (Operating Rules) - The technical specifications adequately specified the limits and conditions of operation (LCO) reflecting those specified in the safety case. In addition, the surveillance records and compliance check sheets demonstrated that the technical specifications were adhered to during operations. We therefore assigned a rating of Green (no formal action) for LC 23.
- LC 24 (Operating Instructions) - We examined a number of station operating instructions (SOIs) and maintenance instructions (MIs). We found a number of quality issues with the maintenance instructions sampled. However, we recognise that there is currently a programme of work improving the standard of MIs, evidence of an enhanced MI was provided during the intervention. We therefore assigned a rating of Green (no formal action) for LC 24.
- LC 27 (Safety Mechanisms, Devices and Circuits) - The electrical systems, including Transformers, Grid Systems and Main Electrical System were considered as safety related systems. We examined and confirmed that they were adequately maintained and tested on a regular basis. We judged that a rating of Green (no formal action) was appropriate for LC 27.
- LC 28 (Examination, Inspection, Maintenance and Testing) - We examined a number of maintenance schedule items and work order cards. We confirmed that the periodicity of maintenance activities was appropriate and judged that the electrical system plant and equipment was being adequately maintained. We therefore assigned an IIS rating of Green (no formal action) to this LC 28. Notwithstanding this, we found minor compliance shortfalls with a small number of maintenance records where team leaders signatures were missing and delays in the capturing the completed record with the stations asset management system. A regulatory issue has been raised to monitor progress to address these shortfalls.
- LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) - The electrical systems, including Transformers, Grid Systems and Main Electrical System do not contain radioactive material and therefore LC34 was not considered as part of this inspection.
I followed up on a number of ONR reported events and discussed operational performance. No significant safety concerns were raised and I confirmed that the station was taking appropriate action.
I attended the Dungeness Site Stakeholder Group Meeting and presented the ONR quarterly report for Dungeness B. No significant queries were raised to ONR.
Conclusion of Intervention
After considering all of the evidence presented by NGL we concluded that the arrangements and their implementation, associated with the electrical systems (including Transformers, Grid Systems and Main Electrical System) met the requirements of the safety case and were adequate. An IIS rating of Green (no formal action) is considered to be appropriate for the system based inspection and a single regulatory issue has been raised relating to full and accurate maintenance records.
There are no findings from the interventions that could significantly undermine nuclear safety.