Executive summary
Date(s) of inspection:
- February 2025
Aim of inspection
System based inspections (SBIs) are an essential element of ONR’s overall intervention on a nuclear site and consist of a series of inspections which are intended to establish that the basic elements of a site/facility safety case as implemented in Safety Systems, Structures and Components are fit for purpose and that they will fulfil their safety functional requirements.
The aim of this inspection was to determine whether the Reactor Sea Water System (RSWS) can perform its safety duties (safety functional requirements), in line with claims made within the safety case. The RSWS is an important system as it provides a cooling function to the Rector support systems including the Pressure Vessel Cooling System and Circulator Auxiliary Cooling System, which were sampled during this inspection.
Subject(s) of inspection
- LC10 - Training - Rating: GREEN
- LC23 - Operating rules - Rating: GREEN
- LC24 - Operating instructions - Rating: GREEN
- LC27 - Safety mechanisms, devices and circuits - Rating: GREEN
- LC28 - Examination, inspection, maintenance and testing - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This inspection on EDF Torness' RSWS was carried out by a multidisciplinary team of ONR Specialist Inspectors to consider the adequacy of implementation of the licensee’s arrangements with regards to Licence Condition compliance and Corrosion Management.
During this system based inspection, I sampled the following to inform my judgement:
- Discussions with RSWS System Owners relating to training & development, a sample of completed training records and role profiles for Licence Condition 10;
- Enactment of the RSWS safety case through application of the Post-Trip Cooling Equipment Technical Specification to ensure Limits and Conditions of operation and plant availability are appropriately implemented for compliance with Licence Condition 23;
- Review of RSWS Operating Instructions and Post-Trip Cooling Equipment Surveillance Requirements, and their relation to the safety case as per Licence Condition 24;
- The plant walkdown of the RSWS and discussions with system owners relating to state of plant for Licence condition 27 and 28; and
- Review of completed maintenance activities on pumps and valves associated with the RSWS which included Work Order Cards, Maintenance Task management, and Plant Item Maintenance Instructions for compliance with Licence condition 28.
ONR inspectors challenged the 'as-found' condition of the reactor sea water system strainers and influenced improvements to be made to the leak management arrangements.
Conclusion
Based on my sample from this System Based Inspection, I conclude that:
Site Licence Condition 10 - Training
ONR Inspection Rating - GREEN (No formal Action)
I am content that EDF are managing the training of RSWS personnel in accordance with the expectations of LC10. I therefore consider an inspection rating of GREEN (No Formal Action) to be appropriate for Licence Condition 10.
Site Licence Condition 23 - Operating Rules
ONR Inspection Rating - GREEN (No formal Action)
I am content that EDF are operating the RSWS in alignment to the operating rules as defined in the safety case. Therefore I consider an inspection rating of GREEN (No Formal Action) to be appropriate for Licence Condition 23.
Site Licence Condition 24 - Operating Instructions
ONR Inspection Rating - GREEN (No formal Action)
I am content that EDF are operating the RSWS area in alignment to the operating instructions as defined in the safety case. Therefore I consider an inspection rating of GREEN (No Formal Action) to be appropriate for Licence Condition 24.
Site Licence Condition 27 - Safety Mechanisms, Devices and Circuits
ONR Inspection Rating - GREEN (No formal Action)
I am content that EDF are operating the Reactor Sea Water System area in alignment to the requirements of Licence Condition 27. Therefore I consider an inspection rating of GREEN (No Formal Action) to be appropriate for Licence Condition 27.
Site Licence Condition 28 - Examination, Maintenance, Inspection and Testing
ONR Inspection Rating - GREEN (No formal Action)
I am content that EDF are adequately maintaining the RSWS and consider that, after improvements to the leak management, EDF is maintaining the Reactor Sea Water System in alignment with the requirements of LC28. Therefore I consider an inspection rating of GREEN (No Formal Action) to be appropriate for Licence Condition 28.
Overall, from my sample of evidence in combination with the plant walkdown, I consider the RSWS is adequately delivering its safety functions.
Therefore, an overall GREEN rating for this system based inspection is considered appropriate. The intervention findings were shared with EDF as part of the normal inspection feedback process.