- Site: Dungeness B
- IR number: 22-046
- Date: June 2022
- LC numbers: 28
Executive summary
Purpose of Intervention
The purpose of this intervention was to carry out a licence condition compliance inspection at EDF Energy Nuclear Generation Limited’s Dungeness B power station in line with the planned inspection programme contained in the Dungeness B Integrated Intervention Strategy for 2022/23. This intervention is in support of the ONR decision to permission Dungeness B’s Initial Defuelling Safety Case.
Interventions Carried Out by ONR
ONR Mechanical Engineering Inspectors carried out inspections against the requirements of Licence Condition 28: examination, inspection, maintenance and testing to inform the ONR decision relating to the issue of a licence instrument for the consent to commence defuelling operations (Licence Condition 22).
I took a sample of the nuclear safety significant activities being undertaken during the Statutory Maintenance Outage on Reactor 21, as outlined in the Dungeness B Maintenance Schedule. This was prior to the submission of the Initial Defuelling Safety Case.
The intervention included examination, inspection, maintenance and testing of the:
- gas circulators,
- vessel cooling,
- CO2 safety relief valves,
- fuelling machine, and
- details of the end of generation plant preservation and maintenance schedule suspension process.
Explanation of Judgement if Safety System Not Judged to be Adequate
This intervention was not a System/Structure Based Inspection hence no judgement of the safety system was made.
Key Findings, Inspector’s Opinions and Reasons for Judgements Made
Based on my sampling, I am satisfied from a mechanical engineering perspective that during the Dungeness B Reactor 21 2022 (019) Statutory Maintenance Outage; examination, inspection, maintenance and testing associated with the:
- gas circulators,
- vessel cooling,
- CO2 safety relief valves, and
- fuelling machine,
- is performed in accordance with the requirements of the Dungeness B Maintenance Schedule. In addition, I am satisfied that the end of generation plant preservation and maintenance schedule suspension process is being adequately controlled, in line with the requirements of the safety case.
Conclusion of Intervention
Based on my sampling undertaken as part of this intervention, I am satisfied that the Licence Condition 28 arrangements and implementation is adequate with no significant shortfalls. I therefore give this intervention an Integrated Intervention Strategy rating of GREEN.
The findings of this inspection will be considered during the assessment of the Dungeness Initial Defuelling Safety Case.