EDF Energy – Nuclear Generation Ltd – Hinkley Point B Planned Intervention
- Site: Hinkley Point B
- IR number: 15-093
- Date: October 2015
- 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) Hinkley Point B power station, undertaken as part of the planned intervention strategy for the Civil Nuclear Reactor Programme (CNRP) of the Office for Nuclear Regulation (ONR).
The work was carried out in line with the planned inspection programme contained in the Hinkley Point B Integrated Intervention Strategy (IIS).
Interventions Carried Out by ONR
I (the nominated site inspector for Hinkley Point B) with an inspection team from NGL’s Independent Nuclear Assurance (INA) carried out a System Based Inspection (SBI) on the Heating and Ventilation (H&V) systems, specifically the Central Control Room (CCR) ventilation system and the Contaminated Ventilation Extract System (CVES).
I also discussed progress with the new diverse shutdown and hold down system with station staff.
Explanation of Judgement if Safety System Not Judged to be Adequate
This system based inspection judged that the arrangements and their implementation, associated with H&V system, met the requirements of the safety case and are deemed adequate.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the system based inspection on the H&V system I concluded that:
- LC 10 (Training) – I examined the role profile and training records for a sample of the personnel involved in the maintenance and testing of the H&V systems. The evidence identified the training requirements for each role profile and I found that all necessary training was in date. I therefore assigned an IIS rating of 3 (adequate) to this inspection.
- LC 23 (Operating Rules) – I was satisfied that the limits and conditions contained in the Technical and Environmental Specifications met the relevant requirements of the existing safety case. A number of potential enhancements to the operating rules were identified and discussed with the site. Overall, I considered that the safety case was adequately represented on the plant and within the associated plant documentation and I therefore assigned an IIS rating of 3 (adequate) to this part of the inspection.
- LC 24 (Operating Instructions) – I reviewed a number of instructions including Station Operating Instructions, maintenance instructions and plant operating instructions. The supplied documentation was of a satisfactory quality and followed the standard formatting and layout. The Station personnel demonstrated a sound understanding of the equipment and the maintenance requirements. I therefore assigned an IIS rating of 3 (adequate) to this inspection.
- LC 27 (Safety Mechanisms, Devices and Circuits) – I judged that the CCR ventilation system incident dampers had safety significance and were required to close on demand to preserve the tenability of the CCR. I considered that the documentation accurately reflected the as-built plant and that the plant was being regularly monitored, inspected and maintained. I therefore assigned an IIS rating of 3 (adequate) to this inspection.
- LC 28 (Examination, Inspection, Maintenance and Testing) – I reviewed the maintenance work instructions and work orders for the CCR ventilation and CVES. I also reviewed the information technology systems that had been developed to plan, track, execute, record the results and derive trends/system health statistics. I concluded that the CCR ventilation and CVES systems were well maintained with adequate systems in place to document the maintenance requirements. I therefore assigned an IIS rating of 3 (adequate) to this inspection.
- LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) – I discussed LC34 issues and reviewed relevant information including recent station performance metrics on environmental safety, the LC34 leak schedule (which contained two defects on the CVES system) and an event from earlier in the year when irradiated fuel was handled at the buffer store whilst a centrifugal fan was unavailable. Overall I was satisfied that aspects of the CVES relating to leakage and escape of radioactive material and radioactive waste were being managed in an appropriate manner and I therefore assigned an IIS rating of 3 (adequate) to this inspection.
Overall, I concluded that the arrangements and their implementation on the H&V systems met the requirements of the safety case and were deemed to be adequate.
I discussed progress with the new diverse shutdown and hold down systems on site and was pleased to note that the new Nitrogen hold down system had now entered full operation and that 21 out of 24 of the Super Articulated Control Rods had been loaded.
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
There were 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 of Hinkley Point B power station as set out in the Integrated Intervention Strategy, which will continue as planned.