SBI 29 – Buildings, Structures and Infrastructure
- Site: Heysham 1
- IR number: 18-134
- Date: October 2018
- LC numbers: 10, 23, 24, 27, 28
Purpose of Intervention
The purpose of this intervention was to carry out a system based inspection at EDF Energy Nuclear Generation Limited’s (NGL’s) Heysham 1 power station in line with the planned inspection programme contained in the Heysham 1 Integrated Intervention Strategy (IIS) for 2018/19.
Interventions Carried Out by ONR
A civil engineering specialist inspector, assisted by the Heysham 1 nominated site inspector performed a system based inspection (SBI) of the Buildings, Structures and Infrastructure system to judge the system performance against its safety function. Through examination of this system and associated sub-systems, we performed compliance inspections against the following Licence Conditions (LCs):
- LC 10 – Training
- LC 23 – Operating rules
- LC 24 – Operating instructions
- LC 27 – Safety mechanisms, devices and circuits
- LC 28 – Examination, inspection, maintenance and testing
We considered that LC 34 (Leak and Escape of Radioactive Material and Radioactive Waste) was not applicable to the sampled system components.
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
From the areas sampled during this inspection, we judged that overall the Buildings, Structures and Infrastructure system met the requirements of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
With respect to the system based inspection the following judgements were made;
- LC 10 (Training) – We examined the training records for a sample of the personnel involved in the inspection of the system. We found that essential training was generally within date, with one anomaly found. Notwithstanding this point, we judged that compliance with LC 10 met ONR’s expectations and hence assigned an inspection rating of Green.
- LC 23 (Operating Rules) and LC 24 (Operating Instructions) – Based on the evidence sampled we concluded that suitable limits and conditions had been derived from the safety case, and are implemented through the technical specifications (operating rules) and station operating instructions. We were satisfied that suitable arrangements were in place to control the availability of systems structures and components qualified against external hazards and specifically, the buildings claimed in the hazards and seismic safety cases. We found that the sampled operating instructions clearly identified appropriate operator actions to be taken following receipt of warnings of significant high winds, following high wind or seismic events. We judged that compliance with LC 23 and LC 24 was consistent with ONR’s expectations and hence assigned an inspection rating of Green to both licence conditions.
- LC 27 (Safety Mechanisms, Devices and Circuits) – We sampled devices identified in the station’s maintenance schedule against safety case requirements. We confirmed that the seismic monitoring equipment was functional and available. We also confirmed that the non-return flap valves in the Turbine Hall flood barrier were available and met the requirements of the associated technical specification. We therefore considered that compliance with LC 27 met ONR’s expectations and hence assigned an inspection rating of Green.
- LC 28 (Examination, Inspection, Maintenance and Testing) – We sampled the inspection and maintenance requirements associated with a sample of the buildings, structures and infrastructure. Based on the evidence sampled and the plant walk-down we considered that inspections were being undertaken in line with the requirements of the maintenance schedule and that overall the system was in an acceptable condition. Although we did not identify any immediate threat to the integrity of the buildings, structures and infrastructure, we observed a number of areas where the condition of the structures can be improved. We were content that the station is aware of the defects in the structures and that it is implementing a significant plan of investment to address them in a timely manner. We identified a number of areas where further information was required to address our queries, but which was not available at the time of the inspection. Actions have been placed on the licensee to provide the required information. Overall, compliance with LC 28 was considered acceptable and therefore an inspection rating of Green was assigned.
A single ONR level 4 issue has been raised to capture the actions identified in this intervention report. Satisfactory close-out of the issue will be monitored by the ONR nominated site inspector as part of routine regulatory business.
Conclusion of Intervention
Following the system based inspection of the Buildings, Structures and Infrastructure system we judged that compliance with LC10, 23, 24, 27 and 28 met the expected standards and were rated as Green. Overall, we judged that the Buildings, Structures and Infrastructure system met the requirements of the safety case.
There were 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 Heysham 1 power station as set out in the integrated intervention strategy, which will continue as planned.