Executive summary
Purpose of Intervention
The purpose of this intervention was to undertake compliance inspections at EDF Energy Nuclear Generation Limited’s Sizewell B power station, in line with the planned inspection programme contained in Sizewell B’s Integrated Intervention Strategy (IIS) for 2020/21.
Interventions Carried Out by ONR
This systems based inspection examined evidence to determine compliance against five key Licence Conditions (LCs), selected to help determine whether the safety case requirements of the system concerned are adequately implemented, and safety systems and structures are fit for purpose and will fulfil their safety functional requirements . The licence conditions assessed were: Licence Condition 10 (Training), Licence Condition 23 (Operating Rules), Licence Condition 24 (Operating Instructions), Licence Condition 27 (Safety Mechanisms, Devices and Circuits), Licence Condition 28 (Examination, Inspection, Maintenance and Testing).
It was judged that Licence Condition 34 (Leakage and Escape of Radioactive Materials) was not applicable to the systems under consideration for this inspection.
The nominated site inspector, a Mechanical Engineering specialist inspector, a Mechanical nuclear associate and a Control and Instrumentation specialist inspector conducted a remote System Based Inspection (SBI) of system 09, Fuel Route systems. Throughout this intervention record “I” refers to all the ONR Inspectors identified above. The areas sampled were the following fuel route systems:
- Reactor Building Polar Crane
- Pond Fuel Handling Machine
- Fuel Building Crane
The inspection comprised discussions with the licensee staff remotely and a desktop review of the licensee’s records and other associated safety documentation.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Explanation of Judgement if Safety System Not Judged to be Adequate
Not applicable
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the areas sampled and the evidence I examined during this inspection; I consider that the licensee has adequately implemented the safety case claims relating to the Fuel Route Systems. I am content that the areas of the system I sampled are inspected, maintained, and operated in accordance with the safety case. I identified areas of improvement which I did not consider prejudice to overall nuclear safety. The ratings I have assigned for each of the Licence Conditions are detailed below.
LC 10 (Training) – I examined the training records for individuals involved in the operation, maintenance, inspection and testing of the Pond Fuel Handling Machine and Fuel Building Crane. I identified a shortfall in the completeness of training records for an individual. The licensee was unable to provide the appropriate record, however through discussion and additional evidence, I judged that the personnel undertaking and supervising these activities were suitably qualified and experienced. I have raised a regulatory issue to resolve the shortfall identified.
I did not consider this to be a significant shortfall and the evidence presented was adequate in demonstrating individuals were Suitably Qualified and Experienced (SQEP). I therefore assigned a rating of Green (No formal action) for License Condition 10 compliance.
LC 23 (Operating Rules) – I sampled limits and conditions identified in the safety case for the Polar Crane, Pond Fuel Handling Machine and Fuel Building Crane, to ensure operating rules identified in the safety case were clearly identified and complied with at all times via appropriate surveillances.
From my sample, I judge that the Licensee has an adequate process in place for identifying and implementing the operating rules to demonstrate the safety of and operation of the Fuel Route systems. The licensee was able to demonstrate compliance with their operating rules. I judged therefore that a rating of Green (No formal action) is appropriate for this licence condition.
LC 24 (Operating Instructions) – I examined completed Operating Instructions used for carrying out interlock testing on the Pond Fuel Handling Machine and for testing safety functions of the Polar Crane. I confirmed that operations had been carried out as stipulated in the Operating Instructions. I consider that the Licensee has adequate arrangements in place for the production and implementation of Operating Instructions.
I noted some areas for improvement in the clarity and adequacy for some sections of the Operating Instructions sampled. I did not consider these findings where significant to overall nuclear safety and don’t intend on following up outside of normal regulatory business. However, I did raise these as observations with the Licensee for consideration of potential improvements. I therefore judge that a rating of Green (no formal action) is appropriate for this licence condition, License Condition 24.
LC 27 (Safety Mechanisms, Devices and Circuits) – I reviewed the maintenance and test records associated with safety mechanisms on the Polar Crane and Fuel Building Crane. Though not able to physically view the plant, I consider the licensee adequately demonstrated that Safety Devices Mechanisms and Circuits were connected and in good working order. The key safety mechanisms devices and circuits were clearly identified, and adequate periodic inspection and testing to confirm plant condition and availability was being undertaken in accordance with the licensee’s arrangements. I judged therefore, that a rating of Green (No formal action) was appropriate for License Condition 27.
LC 28 (Examination, Inspection, Maintenance and Testing) – I sampled the licensee’s maintenance arrangements through reviewing records and discussions with the system engineer. I examined the interlock schedules, completed work order cards and the associated maintenance and inspection procedures, and confirmed that the licensee’s requirements were being implemented adequately.
Overall, I judge that the licensee is undertaking examination, inspection, maintenance and testing in accordance with the specified arrangements and frequencies. I am content that the evidence sampled demonstrated adequate implementation of arrangements. Therefore, I judge that a rating of Green (no formal action) to be appropriate for licence condition 28.
Conclusion of Intervention
Based on my sample, I consider that the Fuel Route (System 09) met the requirements of the safety case, with areas for improvement noted. The inspection findings were shared and accepted by the licensee during the feedback session. I shared regulatory observations and recommendations with the licensee which I don’t intend on following up formally. I also raised a regulatory issue to resolve the shortfall identified.
I consider that the licensee adequately demonstrated ownership and implementation of its safety case. In addition, it demonstrated an adequate understanding of its arrangements to ensure and maintain the safety of its Fuel Route systems.