Office for Nuclear Regulation

Annual Review of Safety (ARoS) and LC21 (Commissioning) compliance inspection

Executive summary

Purpose of Intervention

The purposes of this intervention were to attend a series of meetings covering the Annual Review of Safety (ARoS) and carry out a Licence Condition (LC)21 (Commissioning) compliance inspection on the station’s newly installed Nitrogen injection system, at EDF Energy Nuclear Generation Ltd’s (NGL) Dungeness B Power Station (DNB).  This intervention was undertaken as part of a series of planned interventions that are listed in the DNB Integrated Intervention Strategy 2020/2021. 

Interventions Carried Out by ONR

As nominated Site Inspector, along with the Delivery Lead (Engineering) for operating reactors, I attended the DNB ARoS meeting covering the period for the 1 April 2019 to the 31 March 2020.  The ARoS was conducted in accordance with EDF Energy’s internal process and was compatible with ONR guidance document NS-INSP-GD-058.

In addition, the site inspector also undertook an LC21 (Commissioning) compliance inspection on the station’s newly installed Nitrogen injection system. The inspection was supported by a ONR project inspector.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not Applicable – no system-based inspections were completed during this intervention.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

The ARoS was conducted over two half days. The first half day consisted of a plant walk down of the following areas, followed by a review meeting:

ONR feedback to the station was that the pace of physical changes at the station was significant, with many of the trench covers having been replaced since the completion of some of the event recovery work replacing corroded pipelines and supports. The station has also invested in training of its personnel notably, but not limited to, a new corrosion training room and an additional simulator desk. The station is currently the only one in the fleet to have duel simulators, which further enhances the training of the operators.

Overall, it was concluded that it had been a challenging year for the site given the COVID 19 Pandemic restrictions as well as pressing forward with the station’s delivery of key investment projects.

My LC21 compliance inspection identified that there has been limited inactive commissioning undertaken by DNB, however, it was acknowledged that there will be future inactive commissioning that will be carried out prior to active commissioning. Essentially the contractor BOC has undertaken a functionality test of the new Nitrogen Injection System (NIS) to ensure the installed equipment is fully functional. However, I was able to sample several areas where early inactive commissioning activities had taken place.  Based on the areas examined I considered that the LC21 Compliance inspection warranted a Green rating. However, ONR will revisit the station in 2021 to undertake a further LC21 compliance inspection prior to Active Commissioning which will also enable a regulatory hold point to be released.

During my station visit I held routine engagement meetings with the Station Director TSSM and Plant Manager to discuss my compliance inspection findings and other routine station matters. I also followed up a regulatory issues with the station’s Quality Management Group Head.

Conclusion of Intervention

The ARoS meeting was very positive and overall, it was concluded that it had been a challenging year for the site given the COVID 19 Pandemic restrictions as well as pressing forward with the station’s delivery of key investment projects.

In conclusion to my compliance inspection, I stated during our feedback to the station that ONR would undertake a further LC21 compliance inspection prior to Active Commissioning to enable release ONR’s hold point. From the areas I was able to sample which I considered part of the station’s early inactive commissioning process, I considered that the LC21 compliance inspection warranted a GREEN rating.