Dungeness B - Planned Intervention
- Site: Dungeness B
- IR number: 16-227
- Date: February 2017
- LC numbers: 10, 23, 24, 27, 28, 34
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 Programme (OFP) 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 Carbon Dioxide (CO2) Processing and Blowdown System.
- Meeting with Independent Nuclear Assurance (INA) and plant walk-down.
- Several interactions on event and regulatory issue update.
- Teleconference on Superheater Header Inspection safety case.
Explanation of Judgement if Safety System Not Judged to be Adequate
From our inspection, we judged that the CO2 Processing and Blowdown System met the requirements of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the System Based Inspection on the CO2 Processing and Blowdown System we concluded that:
- LC 10 (Training) –The training records of a number of personnel involved in maintenance and inspection activities associated with the CO2 Processing and Blowdown System. We judged that the personnel undertaking these maintenance and inspection activities were suitably qualified and experienced. However, we found a number of essential training elements to be out of date for the system engineer and the operations team leaders. We therefore assigned a rating of Amber (seek improvement) for LC 10 compliance.
- LC 23 (Operating Rules) – The technical specification sampled 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 operating instructions and maintenance instructions. We judged these documents to be of an adequate standard and therefore assigned a rating of Green (no formal action) for LC 24.
- LC 27 (Safety Mechanisms, Devices and Circuits) – We examined an isolation valve and non-return valve considered to be safety mechanism with the system. We 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 instructions and work order cards. We confirmed that the periodicity of maintenance activities was appropriate and the maintenance instructions appropriately completed. However, we found the pre and blowdown iodine filters had not been maintained in line with the maintenance schedule. Due to this shortfall we have assigned an IIS rating of Amber (seek improvement) to this inspection. Remediation actions were agreed with EDF NGL and regulatory issues have been raised to track completion.
- LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) – Prevention and detection of leakage and escape within the system appeared to be well-managed, with no current leaks of active material. We therefore assigned a rating of Green (no formal action) for LC 34.
I followed up on a number of regulatory issues and a recent ONR reported event. No significant safety concerns were raised and I confirmed that the station was taking appropriate action.
The meeting to discuss the superheater header safety case was informative and no new information has been revealed through the development the case. The meeting provided an opportunity to discuss the permissioning process and raise any technical queries. Further engagement will be conducted as part of the permissioning process.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Conclusion of Intervention
The system based inspection resulted in areas of improvement being identified in response to compliance shortfalls relating to plant EIMT and training. Regulatory issues have been raised in order to seek improvement within areas of identified shortfalls. After considering all of the evidence presented by EDF NGL we concluded that the arrangements and their implementation, associated with the CO2 Processing and Blowdown System met the requirements of the safety case and were adequate. However, given shortfalls identified with respect of LC10 and LC28, an IIS rating of Amber (seek improvement) is considered to be appropriate for this intervention.
There are no findings from these interventions that could significantly undermine nuclear safety.