Office for Nuclear Regulation

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Sizewell B Planned Intervention

Executive summary

Purpose of Intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at EDF Energy Nuclear Generation Ltd's (NGL's) Sizewell B power station, in line with the planned inspection programme of the Operating Facilities Operating Reactors sub-programme intervention plan for 2017/18.

Interventions Carried Out by ONR

I the nominated site inspector undertook a compliance inspection on Organisational Learning during which we measured compliance against the following Licence Condition:

Also during this intervention I:

Explanation of Judgement if Safety System Not Judged to be Adequate

No system inspection was undertaken during this intervention.

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

NGL is currently experiencing a loss of personnel from across the business to a nuclear utility in the United Arab Emirates (UAE). The most acute impact of this has been at Sizewell B through the loss of nine duly authorised persons in operations with the potential for further resignations (other staff are engaged through the recruitment process with the Emirates utility. There is currently no breach of minimum manning levels necessary to meet nuclear baseline requirements; but any further losses of duly authorised persons from operations have the potential, without appropriate contingencies in place, to challenge viability of ongoing commercial generation due to potential inability to meet the emergency scheme and minimum manning requirements.

At present, I am satisfied that this situation represents a reduction of contingency rather than a direct threat to nuclear safety. If the situation was to deteriorate the station's own arrangements under LC 12, 26 and 36 would result in a controlled reactor shutdown and subsequent defuelling. The station has entered event recovery and a fleet critical programme has been enacted to provide additional corporate support. The station presented an overview of the six workstreams that comprise the fleet critical programme.

A regulatory issue has been raised, which requires NGL to provide written briefings to ONR on a quarterly basis, detailing the status of its fleet critical programme for operations manning.

Working time and control of worker fatigue is governed by the NGL fleet wide arrangements and supporting working time risk assessment. The collective agreement between Nuclear Generation and the Trade Unions specifies conditions to ensure that Nuclear Generation employees' rights under the Working Time Regulations are protected while retaining flexibility allowed under the law to help meet operational variations in workload, such as statutory outages, and to accommodate controlled extended working by individuals.

I observed inconsistencies across departments at Sizewell B in the application of working time arrangements. In operations in particular the station's baseline rotas planned for the RO15 outage involve certain staff working at or close to the limits set out in the company arrangements without any formal requirement for a risk assessment to be undertaken. Furthermore, there is no requirement to undertake any formal risk assessment for staff, in particular those interfacing with nuclear significant plant, working up to thirteen consecutive twelve hour shifts.

Whilst not a compliance issue under working time regulations, this arrangement requires in my opinion further examination in terms of impact on worker fatigue in the context of nuclear safety. Investigations into certain incidents that have occurred elsewhere in the fleet in recent years have attributed worker fatigue to be a contributory factor during outages.

I have therefore raised a regulatory issue which requires the station to undertake a review of its planned working patterns for its staff for Reactor Outage15, in particular a discrete number of individuals working close to or at existing limits in its company arrangements.

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

I consider that, based on the evidence acquired during this intervention, that an inspection rating of Green is appropriate for LC 36 (Organisational Capability).