Executive summary
Date(s) of inspection: September 2024
Aim of inspection
The purpose of this inspection was to enable ONR to form a view on the claims made within the safety case on the Evaporator Delta (Evap D) ventilation system under the control of the Highly Active Liquor Evaporation and Storage (HALES) and verify that the key equipment is available and maintained.
The Environment Agency also assessed SL’s compliance with the applicable permit conditions.
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
- LC34 - Leakage and escape of radioactive material and radioactive waste - Rating: GREEN
- Overall Inspection Rating - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This Intervention Record (IR) captures key regulatory observations made during a planned system based inspection (SBI) of the Highly Active Liquor Evaporation and Storage (HALES) facility Evaporator D Ventilation systems. ONR’s System Based Inspection process examines evidence to determine compliance against six key licence conditions (LCs) 10, 23, 24, 27, 28 and 34.
For Licence Condition 10, I targeted the training of three HALES employees (maintenance engineers and team leads) who carried out maintenance on the C3/C5 gamma interlock systems and reviewed the qualification and experience of the HALES Evaporator D System Health Engineer. Overall, I judged that the required standard was met and an inspection rating of Green (no formal action) is appropriate against LC10.
For Licence Condition 23 and 24, I targeted the relevant Operating Rules (ORs), Referenced Operating Instructions (ROI), Operating Instructions (OI) and Emergency Instructions (EI) in connection with HALES Evaporator D ventilation system. Overall, I was satisfied that the safety case clearly identifies the fault sequences and that the operation and emergency instructions followed a detailed step wise format and contained the relevant steps to meet the safety case requirements. Based on the evidence sampled I judge that an inspection rating of Green (no formal action required) is merited against License Conditions 23 and 24.
For LC27, I targeted the relevant safety mechanisms identified within the Evaporator D ventilation system safety case. For LC28, I targeted the last completed maintenance of the preselected safety mechanisms and the System Health Reports (SHR) for the Evaporator D ventilation system. Overall, I judge that the HALES arrangements for maintenance and asset management of Evaporator D ventilation safety systems are adequate and was satisfied that the condition of the ventilation systems and its associated safety mechanisms. However for the SHR sampled a shortfall was identified as not all areas of the SHR were populated. This shortfall had been previously identified in a LC28 inspection carried out in April 2023 which was rated amber and a Level 3 Regulatory Issue was raised to address the shortfall. I am satisfied that no further action is required to address the shortfall in the SHR as this shortfall has previously been identified and a Regulatory Issue is in place to address it. Notwithstanding the shortfall in the SHR, overall based on the evidence sampled, I judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate against Licence Condition 27 and 28.
For LC34; from the information provided, I was satisfied that the appropriate measures were in place to prevent and manage the leakage and escape of radioactive material in connection with HALES ventilation system. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate against LC 34
From the areas sampled, I provided some regulatory advice and observations but did not identify any shortfalls in the implementation of the licensee’s arrangements for nuclear safety.
Based upon the areas sampled I judge that the safety functions associated with Evaporator D ventilation systems (which support the relevant claims in the safety case) under the control of the HALES have been adequately implemented.
Conclusion
From the evidence sampled during the inspection, I judge that HALES has adequately implemented the safety function of the Evaporator D ventilation systems and that the formal arrangements for LCs 10, 23, 24, 27, 28 and 34 are being adequately implemented. For LCs 10, 23, 24, 27, 28 and 34 an inspection rating of Green (no formal action) is merited.
Based upon the areas sampled I judge that the safety functions associated with Evaporator D ventilation systems (which support the relevant claims in the safety case) under the control of the HALES have been adequately implemented.