Sizewell B Planned Intervention
- Site: Sizewell B
- IR number: 16-024
- Date: May 2016
- LC numbers: 10, 23, 24, 27, 28, 34
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
- LC10 training - a sample of training records were reviewed 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. On the basis that relevant good practice was generally met and no deficiencies in compliance arrangements were identified this element of this inspection was given an inspection rating of green.
- LC23 and LC24 operating rules and instructions - 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 three systems. The licensee demonstrated adequate knowledge and understanding in the areas of the SSR and how they relate to the operating rules and instructions in place for the three systems. The LC23 and LC24 element of this inspection were rated as green.
- LC27 safety mechanisms - the licensee demonstrated that the safety mechanisms, devices and circuits associated with the three systems were clearly defined and well maintained, which was confirmed through a plant inspection. I judge the LC 27 element of this inspection to warrant an inspection rating of green.
- LC28 maintenance - 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. The documentation sampled showed that suitable records had been produced for maintenance activities. I judge the LC28 compliance element of this inspection to be rated green.
- LC34 leakage and escape - this was considered for the RVLIS. I judge that the system design and arrangements in place for detecting and monitoring potential leakage are adequate, warranting an associated rating of green.
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.