Office for Nuclear Regulation

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EDF Energy Nuclear Generation Limited (NGL) 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 (NGL) Sizewell B (SZB) power station in line with the planned inspection programme contained in the Sizewell B Integrated Intervention Strategy (IIS). The compliance inspection and information exchange meetings were carried out by two Nominated Site Inspectors and observed by three International Nuclear Inspectors from the Swedish Radiation Safety Authority, United States Nuclear Regulatory Commission and Spanish Nuclear Safety Council. Independent Nuclear Assurance (INA) representatives attended as observers in line with the ONR/INA joint protocol agreed practice.

Interventions Carried Out by ONR

I undertook a safety case informed System Based Inspection [SBI-01] of the Main Steam System (MSS) and Steam Generator Blowdown System (SGBS). The inspection sampled compliance against several licence conditions. These were 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 the 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.

During this site visit I also had a meeting with the Licensee to discuss proposals for the forthcoming reactor outage and attended a public meeting of the Sizewell Stakeholder Sub Group to discuss the emergency plan.

Explanation of Judgement if Safety System Not Judged to be Adequate

I judge that the implementation of the arrangements associated with the MSS and SGBS, meet the requirements of the safety case and are adequate.

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

From an LC10 perspective, a sample of training records was performed to ascertain that those performing operations and maintenance on plant that affect safety were adequately trained and experienced to perform the task. I judged that these elements were in accordance with the associated training requirements. Therefore, I judge the LC10 element of this inspection to be adequate, warranting an associated Integrated Intervention Strategy (IIS) rating of 3 - Adequate.

From an LC23 and LC24 perspective, based on the evidence sampled during this inspection, the implementation of the technical specifications, commentaries, and schedules were judged to be consistent with the claims presented within the Sizewell B Station Safety Report (SSR) for the MSS and SGBS and associated systems. The licensee demonstrated adequate knowledge and understanding in the areas of the safety case and how they relate to the operating rules and instructions in place for the MSS and SGBS. I judge the LC23 and LC24 element of this inspection to be adequate, warranting an IIS rating of 3 - Adequate.

From an LC27 perspective, the licensee demonstrated control of alignment of plant through utilising plant locking and administrative arrangements, which were confirmed through the plant inspection. I judge the LC 27 element of this inspection to be adequate, warranting an IIS rating of 3 - Adequate.

From an LC28 perspective, the licensee demonstrated that there are adequate processes, procedures and records in place for the examination, inspection, maintenance and testing of plant important to safety. Several samples were taken and suitable records were produced for each sample. I judge the LC28 compliance element of this inspection to be adequate, warranting an associated IIS rating of 3 - Adequate.

From an LC34 perspective, the licensee demonstrated that containment is being appropriately maintained and that radioactive material and waste management is in compliance with the licensee's arrangements. I consider that the LC34 element of this inspection to be adequate, warranting an associated IIS rating of 3 - Adequate.

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 inspection against LCs 10, 23, 24, 27, 28 and 34, for the MSS and SGBS I consider that the requirements of the safety case have been adequately implemented at Sizewell B.

A number of observations were made as a result of this system based inspection, which will be addressed as part of the licensees own arrangements given that they are of low nuclear safety significance and they will be followed up as part of routine regulatory business. There are no findings from this inspection that could significantly undermine nuclear safety.