- Site: Torness
- IR number: 21-155
- Date: February 2022
- LC numbers: 10, 23, 24, 27, 28, 34
Executive summary
Purpose of Intervention
The purpose of this intervention was to undertake compliance inspections at EDF Energy Nuclear Generation Limited’s Torness power station, in line with the planned inspection programme contained in the Torness Integrated Intervention Strategy (IIS) for 2021/22.
Interventions Carried Out by ONR
Systems based inspections examine evidence to determine compliance against six key Licence Conditions (LCs), selected to help determine whether the safety case requirements of the system concerned are adequately implemented, and safety systems and structures are fit for purpose and will fulfil their safety functional requirements. The six licence conditions assessed were: Licence Condition 10 (Training), Licence Condition 23 (Operating Rules), Licence Condition 24 (Operating Instructions), Licence Condition 27 (Safety Mechanisms, Devices and Circuits), Licence Condition 28 (Examination, Inspection, Maintenance and Testing) and Licence Condition 34 (Leakage and Escape of Radioactive Material and Radioactive Waste).
The nominated site inspector (part time) and mechanical engineering inspector conducted a System Based Inspection of the Heating and Ventilation systems.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the areas targeted and the evidence I sampled and examined during this inspection, I consider the licensee has adequately implemented the safety case claims related to the Heating and Ventilation Systems. I am content that the areas of the system I sampled are examined, inspected, maintained, tested and operated in accordance with the safety case. I identified a number of observations which I did not consider prejudice to overall safety.
The ratings I have assigned for each of the Licence Conditions are detailed below.
LC10 (Training)
I sampled and examined the training records of individuals involved in the examination, inspection, maintenance and testing of the Heating and Ventilation system. I judged that the individuals undertaking and supervising these tasks, including contractors, were suitably qualified and experienced.
For this part of my inspection I therefore judged that a rating of Green (no formal action) was appropriate for this licence condition, LC 10.
LC23 (Operating Rules)
I judged that the licensee adequately demonstrated that in respect of the sampled Heating and Ventilation system operations that may affect safety had an adequate safety case, demonstrating the safety of operations and identifying conditions and limits, which were identified in the station Technical Specifications.
For this part of my inspection therefore I judged a rating of Green (no formal action) to be appropriate for this licence condition, LC 23.
LC24 (Operating Rules)
I confirmed that the licensee has adequate arrangements in place for the production and implementation of Operating Instructions. The requirement to carry out the operating instructions was clearly stated and the licensee clearly demonstrated the link between these requirements and the safety case.
I therefore judged a rating of Green (no formal action) to be appropriate for this licence condition, LC 24.
LC27 (Safety Mechanisms, Devices and Circuits)
I judged the licensee was able to adequately demonstrate that where plant was required to be operated with suitable and sufficient safety mechanisms, devices and circuits, they were properly connected and in good working order. Adequate surveillance confirming plant condition and availability was being undertaken in accordance with the safety case.
I therefore judged that a rating of Green (no formal action) was appropriate for this licence condition, LC 27.
LC28 (Examination, Inspection, Maintenance and Testing)
Examination of the Heating and Ventilation dashboard identified that Physical Condition was a consistently underperforming area. It was identified that this was due to the system being very large resulting in a loss of sensitivity to individual improvements. I raised this as an observation.
I also identified that although ventilation cascade inspections were being done, they were not regularised and on the maintenance schedule. I raised this as an observation.
I judged the licensees arrangements to be adequate and raised the implementation of regular cascade inspections and system dashboard modifications as an observation for the site inspector to follow up as part of normal regulatory business.
I therefore judged that a rating of Green (no formal action) was appropriate for this licence condition, LC 28.
LC34 (Leakage and Escape of Radioactive Material)
I judged the licensee provided adequate evidence demonstrating HEPA filter efficiency was within prescribed limits and confirming that filter banks were appropriately limiting the spread of contamination to atmosphere.
I therefore judged that a rating of Green (no formal action) was appropriate for this licence condition, LC 34.
Plant Walkdown
As part of my inspection, I also undertook a plant walkdown. Generally, I considered housekeeping conditions to meet my expectations.
I noted that in several areas scaffold was being stored in non-allocated areas. I fed this observation back during my feedback. The licensee commented that this would be addressed and if areas were deemed too small, temporary barriers would be set up, I accepted this way forward.
I noted a high number of Defect Tags, most being dated last year. The licensee commented that due to the Covid pandemic, priority had been placed on defects with high safety significance. With the situation now stabilising, it was planned to address the remaining defects. I was content with this response.
I identified several cabinets which were noted as requiring to be locked but were open. The licensee responded that appropriate locks would be provided and it would ensure that no additional cabinet locks were missing. I was content with this way forward.
Conclusion of Intervention
Based on my sample, I consider that the Heating and Ventilation system met the requirements of the safety case. I identified a small number of observations that I consider it appropriate for the site inspector to follow 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 its Heating and Ventilation systems.