The purpose of this intervention was to undertake a licence condition (LC) compliance inspection at EDF Energy Nuclear Generation Limited (NGL) Sizewell B Power Station, in line with the inspection programme contained in the Sizewell B integrated intervention strategy (IIS) for 2016/17. Specifically, this was part of a fleet-wide, corporate LC22 inspection.
As part of this intervention, we inspected NGL's LC22 arrangements for Modification or Experiment on Existing Plant, in accordance with ONR guide NS-INSP-GD-022 Revision 3. We focused on configuration control of plant in the process of being modified. The intervention was based upon a review of associated procedures and interrogation of various lists including open Category 1, 2 and 3 lists of modifications, safety case anomalies, defeat of interlocks and long term out of service plant and interviews with station staff. The intervention was undertaken jointly with the station's Independent Nuclear Assurance (INA) evaluator.
No safety system inspection was undertaken, hence this is not applicable.
From our inspection of the arrangements for the control of a modification, focusing on configuration control of plant being modified, we noted sufficient checks and balances within the procedures, electronic modification form and Asset Management System to allow for adequate configuration control.
We sampled how all the open modifications on the station are controlled. This showed that a number of key performance indicators are monitored, and review meetings are conducted. We did note a number of long standing modifications which appeared to be master or replicant modifications, which were essentially repeat modifications. These made identifying the real longer term active modifications more difficult. We also noted that several responsible engineers (RE's) were responsible for a considerable number of modifications. However, these are considered to be minor shortcomings with the oversight given to active modifications and support to RE's to progress modifications, being over and above NGL's corporate requirements.
The list of long term out of service plant showed that there was no long term out of service plant, which indicated that isolations were under control.
The station manage safety case anomalies differently to corporate arrangements, however from the sampling carried out we considered that these control arrangements were adequate.
There were no fuel route interlock defeats in place and a review of the associated management arrangements demonstrated that defeat of interlocks was under adequate control.
Based on our inspection, we judged that the implementation of the arrangements for LC22 reflect relevant good practice and have rated this intervention as Green.
Overall, we consider that the arrangements and their associated implementation for LC22 for the sample undertaken met with legal requirements; we have therefore rated this inspection as Green.
There are no findings from this inspection that could significantly undermine nuclear safety nor require a change to the planned interventions and inspections of Sizewell B.