Executive summary
Date(s) of inspection:
Aim of inspection
System based inspections (SBIs) are an essential element of ONR’s overall interventions on nuclear licensed sites. They are intended to establish that the basic elements of a site/facility safety case as implemented in safety systems and structures are fit for purpose and that they will fulfil their safety functional requirements. The aim of this inspection is to confirm that the fuel route (fuelling machine, buffer store, irradiated fuel dismantling facilities and vaults, fuel assemblies and plug unit maintenance facilities, ponds, flask handling and discharge facilities) can meet its safety case nuclear safety requirements and arrangements for the Licence Conditions (LCs) identified are being adequately implemented.
The inspection was in line with the planned inspection programme contained in the Dungeness B integrated inspection strategy for 2022/23.
Subject(s) of inspection
The chosen inspection sample included:
- 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
Key findings, inspector's opinions and reasons for judgement made
This intervention assessed the licensee’s safety case for the fuel route and focussed on the Irradiated Fuel Dismantling Facility. It was conducted by mechanical engineering, fault studies, control and instrumentation, and radiological protection inspectors. They were supported by the nominated site inspector. Throughout this intervention record, “I” refers to all ONR inspectors.
This inspection involved:
- discussions with licensee staff;
- a review of licensee safety case documents; and
- a walkdown of licensee facilities.
The inspection was informed by the Office for Nuclear Regulations technical guidance (
www.onr.org.uk/operational/tech_insp_guides/index.htm).
From my inspection sample, I judge that the licensee has adequately demonstrated implementation of its irradiated fuel dismantling facility safety case. I identified minor areas for improvement which I do not consider prejudice nuclear safety. The Licence Condition ratings are summarised below:
- Licence Condition 10 (Training) – I sampled on-the-job training and task performance evaluation guide for the fuel route technician on the irradiated fuel disposal facility. I sampled the process used to refresh and reskill operators and capture progress and records of training. I judge that training for operations within the irradiated fuel disposal cell is adequate. Hence, I assigned a Green (No formal action) rating for Licence Condition 10 compliance.
- Licence Condition 23 (Operating rules) – I sampled the irradiated fuel disposal facility safety case limits and conditions. I judge the operating rules were clearly identified in the station Technical Specifications, adequately linked to the safety case and were understood by operators. Hence, I assigned a rating of Green (No formal action) for Licence Condition 23 compliance.
- Licence Condition 24 (Operating instructions) – I sampled the irradiated fuel disposal facility fuel route operating instructions. I judge the operating instructions were clear and identified the necessary checks and actions required in the interests of safety. I found that these were adequately linked to the operating rules and that records showed compliance. Hence, I assigned a Green (No formal action) rating for Licence Condition 24 compliance.
- Licence Condition 27 (Safety devices, mechanisms and circuits) – I sampled the irradiated fuel disposal facility safety mechanisms, devices and circuits. I judge the licensee adequately demonstrated they were in good working order. I identified a minor shortfall in the testing regime for the breakdown hole ram weight sensing system and will follow resolution as part of normal regulatory business. Overall, for LC27 I judged that the licensee adequately demonstrated compliance with its arrangements. Hence, I assigned a Green (No formal action) rating for Licence Condition 27 compliance.
- Licence Condition 28 (Examination, inspection, maintenance and testing) – I sampled the irradiated fuel disposal facility examination, inspection, maintenance and testing. I judge the licensee demonstrated that it makes and implements adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of plant which may affect safety. I identified a minor shortfall in the use of uncalibrated equipment and will follow up the licensee’s actions as part of normal regulatory business. Overall, for LC28 I judged that the licensee adequately demonstrated compliance with its arrangements. Hence, I assigned a Green (No formal action) rating for Licence Condition 28 compliance.
- Licence Condition 34 (Leakage and escape of radioactive material and radioactive waste) – I sampled the licensee’s arrangements for detecting and preventing an escape of radioactive material in, or from the irradiated fuel dismantling facility. I judge that the licensee adequately demonstrated compliance with these arrangements. Hence, I assigned a Green (No formal action) rating for Licence Condition 34 compliance.
Conclusion
Based on my sample, I consider that the Irradiated Fuel Dismantling Facility met the requirements of the safety case. I identified a small number of observations that I consider it appropriate to be followed up as part of normal regulatory business. The inspection findings and observations were shared with and accepted by the licensee during the feedback session.
I consider the licensee adequately demonstrated ownership and implementation of its safety case. In addition, it demonstrated an adequate understanding of its arrangements to ensure and maintain the safety of the Irradiated Fuel Dismantling Facility.
My overall judgement is that the Irradiated Fuel Dismantling Facility adequately fulfils the requirements of the safety case.