Date(s) of inspection:
- August 2023
Aim of inspection
The purpose of this inspection was to enable ONR to form a view on the claims made within the safety cases associated with the electrical and back-up systems under the control of the Highly Active Liquor Evaporation and Storage (HALES) facility and verify that the key equipment is available and adequately maintained.
Subject(s) of inspection
- LC10 – Training – Rating: Not rated
- LC23 – Operating rules – Rating: Not rated
- 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: Not rated
- 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 Electrical and Back-up systems. ONR’s System Based Inspection process usually examines evidence to determine compliance against six key licence conditions (LCs) 10, 23, 24, 27, 28 and 34. This SBI has been reduced to three LCs- LC24, 27 & 28 following learning from the SBI on electrical systems at High Level Waste Plant (HLWP). In the HLWP inspection for LC10 the subject matter experts are the same people for both HALES and HLWP, for LC23 there were no direct safety case claims made on the electrical systems and for LC34 the electrical systems where found to be not sufficiently relevant to the leakage and escape of radioactive material or waste. LC 24, 27 and 28 were selected for this inspection in view of their relevance to ensuring nuclear safety. Focussing on just these three LCs was deemed proportional and helped reduce the resource burden on both ONR and Licensee.
For Licence Condition 24, the safety case makes no direct safety claims for the provision of electrical power to the plant but HALES recognises that the loss of electrical power is an initiating event for several faults. I targeted my inspection on the relevant emergency instructions for the loss of power and the maintenance instructions associated with the electrical boards, diesel generators and UPS batteries. I was satisfied that the instructions followed a detailed step wise format containing the relevant steps to meet the safety requirements. Based on the evidence sampled I judge that an inspection rating of Green (no formal action required) is merited against Licence Conditions 24.
For Licence Condition 27 and 28, I targeted my inspection on a sample of the electrical boards, diesel generators and UPS batteries associated with the electrical supply and undertook a review of the maintenance records and system health reports. On the basis of the maintenance records sampled and the plant inspection of the electrical systems, I was satisfied that the electrical system is being adequately maintained and is in adequate condition. For the system health reports (SHR) sampled, a shortfall was identified as there was no Reliability Engineer assigned to the electrical system and the SHR was not being kept up to date. This shortfall has previously been identified in the 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, 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.
From the areas sampled, I provided some regulatory advice but did not identify any shortfalls in the implementation of the licensee’s arrangements which would necessitate a further inspection of the electrical systems earlier than currently planned.
Based upon the areas sampled I judge that the safety functions associated with the electrical and back-up systems (which support the relevant claims in the safety case) under the control of the HALES have been adequately implemented.
From the evidence sampled during the inspection, I judge that Sellafield Ltd has adequately implemented the safety function of the electrical and back-up system (which support the relevant claims in the safety case) and that the formal arrangements for LCs 24, 27 and 28 are being adequately implemented. For LCs 24, 27 and 28 an inspection rating of Green (no formal action) is merited.