Office for Nuclear Regulation

Return to Service Readiness and LC11(6) (Emergency arrangements) inspections

Executive summary

Purpose of Intervention

This intervention record covers a readiness inspection performed as part of an ONR Operating Facilities Division (OFD) initiative to inspect EDF Energy Nuclear Generation Ltd’s (NGL) Dungeness B (DNB) nuclear power station’s readiness to return to service as a result of it’s extended outage. The extended outage of both rectors is as a result of the station’s on-going event recoveries, regarding corrosion, steam main cracking and its boiler tube safety case.

A return to service readiness inspection (RTS) inspection was undertake in January 2020, however the extent of recovery activities extended beyond the station’s planned start-up date. The reactors have been shut down for over two years, this planned ONR inspection was to further to build regulatory confidence in the Licensee’s ability to adequately conduct those activities which will ensure safe operation of the reactors at power. The Inspection was to determine, via sampling, the adequacy of the stations return to service preparations since ONR’s last inspection. 

Interventions Carried Out by ONR

The inspection was undertaken by ONR Mechanical, Structural Integrity and the Nominated Site Inspector over the period 15th to 20th November 2020. The inspection was jointly undertaken with the station’s own internal regulatory assurance team (INA).

During this inspection, the site inspector also undertook an LC11 (6) (Emergency arrangements) inspection of a shift training exercise and followed up on regulatory issues.

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable, no system-based inspection was undertaken.

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

RTS inspection Findings

This ONR inspection were designed to complement the INA Readiness Surveillance activities as well as facilitating joint working in areas of mutual interest. The INA Readiness Surveillance was a positive with findings and actions which ONR support.

Overall, ONR found that Dungeness B have continued to maintain those areas that were identified as positive  findings from the previous January 2020 inspection and made significant progress in other areas where new issues had been identified as a result of the extended period of shutdown.

For the LC28 compliance inspection, the inspector judged that the Licensee was adequately implementing its arrangements.  They therefore had confidence in Dungeness B’s ability to return to service following the extended outage subject to satisfactory completion of all routine Examination, Maintenance, Inspection and Testing (EMIT), plant preservation EMIT, specific return to service EMIT and outstanding regulatory milestones. An inspection rating: of GREEN for the LC 28 compliance inspection (No Formal Action)– was considered appropriate.

The inspector identified a shortfall in the development of a robust plant preservation plan. Considering this, the inspector has raised a Level 4 regulatory issue to track the station’s progress in addressing it prior to the station’s return to service of both reactors.

For the LC26 compliance inspection, the site inspector found no new issues that undermine confidence in the station’s readiness for return to service, challenges remain within the licensee’s oversight arrangements in some areas of its contract partner’s work activities. Many of the areas sampled and individuals spoken to, provided good evidence that the station had progressed since the January 2020 RTS inspection. The station’s initiatives that have been implemented e.g. maintenance standards, professional to the core expectations and leaders in the field to name a few  appear to be delivering in the areas sampled however, the station needs to sustain this drive and deliver on its performance improvement plan activities.   An inspection rating: of GREEN for the LC 26 compliance inspection (No Formal Action)– was considered appropriate.

LC11(6) Compliance Inspection findings

The site inspector observed a shift training exercise which facilitated the station’s emergency responders to practice and develop their skills.  The site inspector’s main observations of the training exercise were that the scenario facilitated all players to practice their role responsibilities. Given the COVID 19 station arrangements, the Emergency Preparedness Engineer made good arrangements to keep teams socially distant with the use of additional facilities with the separation of teams. The use of the umpires also helped drive the exercise was notable who offering enough guidance without compromising the training benefit in unnecessary prompts or hints. The site inspector considered that this was a good training exercise which warranted a GREEN rating under LC11(6).

Conclusions of Intervention

Based on ONR sampling, overall, the scope of station’s readiness programme and level of engagement were encouraging, particularly in the Operations Department. The RTS intervention has resulted in green ratings against LC26 and 28. There were some minor shortfalls noted against expectations particularly in the development and delivery of plant preservation actions and contract partner oversight.

For the LC11(6) compliance inspection, the inspector identified no significant issues and warranted a GREEN rating (no further regulatory action required)