Office for Nuclear Regulation

Sizewell B LC22 inspection

Executive summary

Purpose of Intervention

This intervention was carried out to determine the adequacy of the EDF Energy Nuclear Generation Ltd (EDF NGL) execution of the invasive installation, test, commissioning and handover of the Westinghouse integrated system for centralised operation (WISCO 2) hardware and software.  These activities took place during Sizewell B (SZB) refuelling outage (RO) 16. The intervention forms part of the Office for Nuclear Regulation’s (ONR)’s intervention strategy for the WISCO-2 project (CM9 – 2018/380576).

Interventions Carried Out by ONR

This inspection was undertaken by three ONR control and instrumentation (C&I) nuclear safety inspectors with the objective of verifying the adequacy of the EDF NGL execution of the invasive installation, test, commissioning and handover of the WISCO-2 PCS and DCS hardware and software. This entailed sampling associated testing and commissioning documentation, undertaking plant walkdowns and holding discussions with relevant stakeholders in relation to Licence Condition (LC) 22 – Modifications or experiment on existing plant, which is an applicable provision of the Energy Act 2013.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

Our inspection of work associated with the invasive installation and testing of the WISCO-2 system during the RO16 outage found adequate implementation of the EDF NGL arrangements for these activities.

Two actions have been identified during the inspection which are required to be resolved prior to return to service of the reactor:

A further ten actions have been raised during the inspection, as identified in this record, to provide information regarding the security arrangements for equipment prior to its installation, the traceability of information within installation and test documentation, the resolution of test anomalies, and the documentation for tests not complete at the time of the inspection. None of these actions are required to be completed prior to the return to service of SZB following RO16.

Conclusion of Intervention

Notwithstanding the actions described above we consider that an inspection rating of Green is appropriate for compliance against LC22 in this instance on the basis that relevant good practice was generally met and any identified deficiencies in compliance arrangements were relatively minor.

It is recommended however, that support only be given for a Consent to allow SZB to return to normal operating service once the two actions associated with the WISCO-2 security case and penetration testing have been satisfactorily addressed.