Office for Nuclear Regulation

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Heysham 1 - SBI05 - Seawater Systems

Executive summary

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) Heysham 1 (HYA) power station. The inspection was conducted in line with the inspection programme contained in the HYA SBI plan for 2017/18.

Interventions Carried Out by ONR

Two Office for Nuclear Regulation (ONR) specialist structural integrity inspectors, which for the purpose of this intervention report shall be referred to as "I", conducted a SBI on the Seawater Systems at HYA nuclear power station. Through examination of this system, I performed compliance inspections against the following licence conditions of the nuclear Site Licence (LC): LC 10: Training; LC23: Operating Rules; LC24: Operating Instructions; LC27: Safety Mechanisms, Devices and Circuits and LC28: Examination, Inspection, Maintenance and Testing. The inspection was based on sampling the implementation of the licensee's arrangements in place at Heysham 1 against each licence condition. Following discussion with the licensee I judged that compliance inspection against LC34: Leakage and Escape of Radioactive Material for the seawater systems was not applicable.

Explanation of Judgement if Safety System Not Judged to be Adequate

I selected the essential cooling water (ECW) system for sampling HYA's arrangements for managing seawater systems, based on its importance for providing cooling to nuclear safety significant systems. I judged that overall, the licensee demonstrated that the ECW was being operated and maintained in accordance with the requirements of the safety case.

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

LC 10 (Training) - I sampled a range of employee training records for individuals with responsibility for the safe operation, maintenance and overall management of the ECW system. 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) - I sampled the licensee's compliance with a number of key operating rules under the site Technical Specifications (TS). The inspection confirmed that the station has made and implemented arrangements to ensure that plant is not operated unless the TS provided to implement the limits and conditions derived from the safety case are satisfied. I judged LC23 aspects of the SBI to meet the legal requirements, with the licensee having identified, implemented and demonstrated compliance with operating rules derived from the safety case, warranting a rating of GREEN.

LC 24 (Operating Instructions) - I sampled a number of the associated plant operating instructions, to confirm that operations important to safety are carried out in accordance with written instructions. An appropriately clear link from the safety case through to operating instructions was evident. I found the operating instructions to be well presented, being in a systematic format and relevant to the tasks in hand. Accordingly, I judged that a rating of GREEN is appropriate.

LC 27 (Safety Mechanisms, Devices and Circuits) - The inspection examined records of Safety Mechanisms to establish how their availability is managed and good working order maintained. The licensee was able to provide evidence that the devices sampled were identified within the safety case, and appropriately maintained through arrangements based on documented procedures with defined acceptance criteria. The records sampled were completed satisfactorily. Therefore, I judged the LC27 aspects of the SBI to be GREEN.

LC 28 (Examination, Inspection, Maintenance and Testing (EIMT)) - The inspection examined the procedures and arrangements in place to ensure EIMT is carried out appropriately for the ECW and the associated pipework, valves and monitoring equipment. I examined the system health score card for the ECW and sampled further maintenance and testing activities, conducted in support of the station MS. I was content that these met the legal requirements; in regard to reports and reviews of maintenance and demonstrated control of the system EIMT requirements. A rating of GREEN was deemed appropriate for LC28.

LC 34 (Leakage and Escape of Radioactive Materials and Radioactive Waste) -Following discussion with the licensee and taking into consideration the operation and function of the ECW, I did not consider the ECW to be a relevant system for inspection under LC34, and therefore it was not considered further as part of this SBI.

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, I am satisfied that the licensee has met the legal requirements for the safe operation and maintenance of the ECW system, which meets the requirements of the safety case.

From the information gathered and evidence obtained during this intervention, I judge that no matters have been identified that are likely to have significant impact on nuclear safety at this time. Therefore, I consider that no additional regulatory action arising from this visit is necessary currently, and the interventions for HYA power station, set out in the integrated intervention strategy, should continue to be implemented as planned.