Sizewell B - SBI03 and 06 - Mid Cycle Review
- Site: Sizewell B
- IR number: 16-257
- Date: March 2017
- LC numbers: 10, 23, 24, 27, 28, 34
Purpose of intervention
The main purpose of this intervention was to undertake a system based inspection (SBI) at EdF Energy Nuclear Generation Ltd's (EdF NGL) Sizewell B (SZB) power station. The system inspected combined system 03 - Reactor Coolant System - RCS (System BB) and system 06 - Emergency Boration System - EBS (System BR). The inspection was conducted in line with the inspection programme contained in the SZB SBI plan for 2016/17.
Interventions Carried Out by ONR
The ONR Site Inspector and two specialist inspectors, referred to as "we" within this report, conducted a SBI of System 03 and 06 (RCS and EBS) at SZB nuclear power station. Through examination of this system, we performed compliance inspections against the following licence conditions of the Nuclear Site Licence i.e. LC 10: Training; LC23: Operating Rules; LC24: Operating Instructions; LC27: Safety Mechanisms, Devices and Circuits; LC28: Examination, Inspection, Maintenance and Testing and LC34: Leakage and Escape of Radioactive Material. The inspection was based on sampling the implementation of the arrangements in place at the station against each licence condition.
During this intervention the Site Inspector also continued hand over to the succeeding Site Inspector, with a Mid-Cycle Review also undertaken.
Explanation of Judgement if Safety System Not Judged to be Adequate
From the inspection we judged that overall the RCS and EBS system met the requirements of the safety case and are adequate.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
- LC 10 (Training) - For this part of the inspection we chose to sample a range of operator training material relevant to the EBS and RCS. For all of the training material reviewed it was evident that a comprehensive structured approach was in place, clearly linking the roles and responsibilities with the training material. The SAP records were viewed to observe the training profiles of the individuals. It was noted and reported back to NGL that there two minor concerns, one which was dealt with before leaving site and the other is already known as a fleetwide issue and is being dealt with separately. From the totality of the evidence gathered during the SBI, I consider that an ONR inspection rating of GREEN is appropriate for LC10.
- LC 23 (Operating Rules) - We sampled the licensee's compliance with a number of key EBS and RCS operating rules, under its Technical Specifications (TS). The inspection confirmed that station has made and implemented arrangements to ensure that plant is not operated unless TS provided to implement the limits and conditions derived from the safety case are satisfied. We judged LC23 aspects of the SBI to be adequate, with Station having identified, implemented and demonstrating compliance with operating rules derived from the safety case, warranting a rating of GREEN.
- LC 24 (Operating Instructions) - During this part of the inspection we sampled a number of the associated station and plant operating instructions, to confirm that operations important to safety are carried out in accordance with written instructions. This included a sample relating to the EBS and RCS TS surveillance requirements. An appropriately clear line of sight from TS at a high level in the safety case through to operating instructions was evident. We found the operating instructions to be well presented, being in a systematic format and relevant to the tasks in hand. Accordingly, we judged that a rating of GREEN is appropriate.
- LC 27 (Safety Mechanisms, Devices and Circuits) - The inspection reviewed records of Safety Mechanisms to establish how their availability is managed and good working order maintained. The station were able to provide adequate evidence that the devices sampled were maintained and available in line with safety case requirements, based on documented procedures and defined acceptance criteria. The records sampled were completed satisfactorily. Therefore, we judged the LC27 aspects of the SBI to be GREEN.
- LC 28 (Examination, Inspection, Maintenance and Testing) - The inspection reviewed the procedures and arrangements in place to ensure Examination, Inspection, Maintenance and Testing (EIMT) is carried out appropriately for the EBS and RCS. We reviewed the SHIP/FLAIR system for an overall picture of system health and sampled further into maintenance and testing activities. We were content that these represented adequate arrangements; in regard to reports and reviews of maintenance and demonstrated adequate control of the system EMIT requirements. A rating of GREEN was deemed appropriate for LC28.
- LC 34 (Leakage and Escape of Radioactive Materials and Radioactive Waste) -This aspect of the inspection considered the Station arrangements for control of leakage and escape of radioactive material or waste. We sampled arrangements for control of leaks on the EBS and RCS systems and found them to be in line with expectations. Some areas for improvement have been identified by station and this was supported by ONR. A rating of GREEN was judged to be appropriate.
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
After considering all the evidence examined during the inspection, we considered that the Reactor Coolant System and Emergency Boration System met the requirements of the safety case.
From the information gathered and evidence obtained during this intervention a minor area for improvement was raised with the licensee in regards to training, which is covered by the current ONR fleet wide level 3 issue. However, no matters were been identified that are likely to have significant impact on nuclear safety on the station at this time. Therefore we consider that no additional regulatory action arising from this visit is necessary currently, and the interventions for SZB power station, set out in the integrated intervention strategy, should continue to be implemented as planned.