Executive summary
Date(s) of inspection: August 2022
Aim of inspection
In support of plans for End of Generation (EOG) at HNB and HPB, EDF has submitted two safety cases to ONR:
- NP/SC 7781 Shutdown Reactor Defuelling Case
- NP/SC 7786 Fuel Handling Defuelling Case
The associated ONR decision records (Shutdown and Defuel) notes that Human Factors aspects of these cases require assessment to support its permissioning of the associated activities. The planned activities included compliance inspections to be completed at HNB and HPB, considering aspects of LC23 and LC24 impacted by the proposed modifications. In support of this, a compliance inspection was completed in June / July 2021 at HNB was completed and is captured in a Licence Conditions 23 and 24 Compliance Inspection Report. This inspection aims to complete similar activities at HPB.
The purpose of the intervention is to inspect EDF’s proposals for, and progress to date, implementation of the EOG safety cases. Given the many similarities between EDF’s extant activities and those required to support EOG, the inspection will consider EDFs extant arrangements, the delta between generation / EOG activities and the step EDF is taking to manage / close such deltas to ensure risks remain ALARP.
Subject(s) of inspection
- LC23 - Operating rules - Rating: Green
- LC24 - Operating instructions - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
The purpose of this intervention was to conduct an Inspection of EDF Energy Nuclear Generation Ltd’s (NGL) at Hinkley Point B (HPB) Power Station. This intervention was undertaken as part of a series of planned interventions that are listed in the HPB Integrated Intervention Strategy.
The intervention was carried out by ONR’s Nominated Site Inspector for HPB and a Human Factors Specialist Inspector over the period 22nd August 2022 until the 28th October 2022, and was rated against Licence Condition 23 (Operating Rules) and Licence Condition 24 (Operating Instructions).
In support of plans for End of Generation (EOG) at HNB and HPB, EDF has submitted two safety cases to ONR:
- NP/SC 7781 Shutdown Reactor Defuelling Case
- NP/SC 7786 Fuel Handling Defuelling Case
The associated ONR decision records (Shutdown and Defuel) note that Human Factors aspects of these cases require assessment to support its permissioning of the associated activities. The planned activities included compliance inspections to be completed at (Hunterston B) HNB and HPB, considering aspects of LC23 and LC24 impacted by the proposed modifications. In support of this, a compliance inspection was completed in June / July 2021 at HNB was completed and is captured in a Licence Conditions 23 and 24 Compliance Inspection Report. This inspection aimed to complete similar activities at HPB.
The purpose of the intervention was to inspect EDF’s proposals for, and progress to date, implementation of the EOG safety cases. Given the many similarities between EDF’s extant activities and those required to support EOG, the inspection will consider EDFs extant arrangements, the delta between generation / EOG activities and the step EDF is taking to manage / close such deltas to ensure risks remain As Low as Reasonably Practical (ALARP).
A discussion with relevant technical staff was held, a follow up virtual (via Teams) inspection was performed, and a subsequent additional inspection was completed with a plant walkdown with an experienced operator and included discussions with various responsible members of EDF NGL staff and task sequence observations. A further review of documents provided was completed.
The SOIs are not yet finalised and are continuing to evolve. In particular, Fuel Free Verification (FFV) Station Operating Instructions (SOIs) are in development and it was noted that this could impact on the ability of the station to demonstrate FFV. In addition, a thorough review of station level documentation has not yet been completed and this poses a risk that all critical tasks are not well captured and communicated for the operators.
A sample review of station level documentation was performed. It was noted that some of the paperwork related to FFV had not been completed. This included the final parts of the overview document and the FFV aspects of the overarching quality plan. The demonstration of the FFV aspects of the documentation is a key part of the early defuelling work and therefore it was my expectation that this would have been resolved at the time of the inspection.
Overall, the operational staff appeared familiar with the instructions and equipment being used for defuelling. There were some indications that any training carried out on the general risks and changes from defuelling may not have been fully effective. Most of these indications are anecdotal, and a further LC12 inspection has been scheduled for further information.
A rating of Green was assigned for LC23, with two recommendations raised. A rating of Green was assigned for LC24, with four recommendations. There were no findings from this inspection that could significantly undermine nuclear safety.
Conclusion
A rating of Green was assigned for LC23, with two recommendations raised. A rating of Green was assigned for LC24, with four recommendations raised. There were no findings from this inspection that could significantly undermine nuclear safety.