Heysham 1 System Based Inspection - SBI 08 - Short Break Supplies System
- Site: Heysham 1
- IR number: 17-190
- Date: December 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) Heysham 1 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 Heysham 1 Integrated Intervention Strategy (IIS).
Interventions Carried Out by ONR
During this intervention, the following key activities were undertaken:
- System Based Inspection (SBI) of the Short Break Supplies System
- Unit Auxiliary Transformer Trip - Information Gathering
Explanation of Judgement if Safety System Not Judged to be Adequate
From our inspection, ONR judged that the Short Break Supplies System met the requirements of the safety case and was adequate.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the System Based Inspection on the short break supplies system ONR concluded that:
- LC 10 (Training) - ONR examined the training records of a number of personnel involved in maintenance and inspection activities associated with the short break supplies system. ONR judged that the personnel undertaking these maintenance and inspection activities were suitably qualified and experienced. ONR therefore assigned a rating of Green (no formal action) for LC 10 compliance.
- LC 23 (Operating Rules) - The Technical Specifications inspected 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 inspected demonstrated that the Technical Specifications were complied with during operations. ONR therefore assigned a rating of Green (no formal action) for LC 23.
- LC 24 (Operating Instructions) - ONR examined a sample consisting of a station operating instruction (SOI) and several maintenance instructions (MIs). ONR 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) - The short break supplies system was considered to meet the definition of a safety mechanism, device or circuit. ONR examined several completed maintenance and test records relating to these systems and confirmed that they were adequately maintained and tested on a regular basis. ONR judged that a rating of Green (no formal action) was appropriate for LC 27.
- LC 28 (Examination, Inspection, Maintenance and Testing) - ONR examined several MIs and work order cards. ONR confirmed that the periodicity of maintenance activities was appropriate and the MIs check lists were appropriately completed. ONR requested clarity on the status and progress of the recommendations made within a Safety System Report for the system inspected. In response ONR has raised a regulatory issue in order to track progress. Otherwise, ONR judged that the short break supplies system plant and equipment was being adequately maintained. We therefore assigned an IIS rating of Green (no formal action) for LC 28.
- LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) - The short break supplies system does not contain radioactive material and therefore LC34 was not considered as part of this inspection.
For the information gathering intervention on the Unit Auxiliary Transformer trip, ONR were content, from an electrical engineering perspective, that station were continuing to work towards fully identifying and understanding the causes of this event and developing and implementing appropriate remediation strategies. ONR was also content with the station's immediate responses to prevent a recurrence.
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
From the evidence sampled during this SBI-08 inspection against LCs 10, 23, 24 and 28, ONR consider that the Short Break Supplies Systems met the requirements of the safety case.
For the information gathering intervention, ONR was content with the explanations, discussions and advice given and was content that there was no need for any regulatory action at this point.
There are no findings from this inspection that could significantly undermine nuclear safety. At present, no additional regulatory action is needed over and above the planned interventions at Heysham 1 Power Station as set out in the Integrated Intervention Strategy, which will continue as planned.