Office for Nuclear Regulation

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Sizewell B Planned Intervention

Executive summary

Purpose of intervention

The primary purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at EDF Nuclear Generation Limited's (EDF NGL) Sizewell B (SZB) power station in line with the planned inspection programme contained in the Sizewell B Integrated Intervention Strategy (IIS). This compliance inspection was carried out by the ONR Nominated Site Inspector and ONR Control and Instrumentation (C&I) Specialist Inspectors.

Interventions Carried Out by ONR

I undertook a safety case informed System Based Inspection [SBI-28] of the Internal Core Neutron Flux monitoring system, External Core Neutron Flux and Nitrogen (N16) monitoring system, and the Reactor Vessel Level Indication System (RVLIS). This inspection sampled compliance against several licence conditions, namely: LC10 (training), LC23 (operating rules), LC24 (operating instructions), LC27 (safety mechanisms, devices and circuits), LC28 (examination, maintenance, inspection and testing) and LC 34 (leakage and escape of radioactive material and radioactive waste). The objective of this inspection was to determine whether the licensee's arrangements for plant operational limits, plant maintenance schedules, staff training requirements and inspection plans were adequate in accordance with safety case requirements.

Explanation of Judgement if Safety System Not Judged to be Adequate

I judge that the implementation of the arrangements associated with the three systems meet the requirements of the safety case.

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

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

From the evidence sampled during this SBI-28 inspection against LCs 10, 23, 24, 27, 28 and 34, I consider that the Internal Core Neutron Flux monitoring system, External Core Neutron Flux and Nitrogen (N16) monitoring system, and the Reactor Vessel Level Indication System met the requirements of the safety case.

There are no findings from this inspection that could significantly undermine nuclear safety. At present, no additional regulatory action is needed over and above the planned interventions of Sizewell B power station as set out in the Integrated Intervention Strategy, which will continue as planned.