- Site: Heysham 2
- IR number: 21-173
- Date: March 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 Heysham 2 power station, in line with the planned inspection programme contained in the Heysham 2 Integrated Intervention Strategy (IIS) for 2021/22.
Interventions Carried Out by ONR
This was a Systems Based Inspection examining evidence to determine compliance against six key Licence Conditions, 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)
- Licence Condition 34 (Leakage and Escape of Radioactive Material and Radioactive Waste)
This intervention assessed the licensee’s safety case application for gas circulators. It was conducted by Mechanical Engineering inspectors supported by the nominated site inspector. Throughout this intervention record, “I” refers to all ONR inspectors.
The inspection involved:
- discussions with licensee staff;
- a review of licensee safety case documents; and
- walkdown of licensee facilities.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Explanation of Judgement if Safety System Not Judged to be Adequate
Not applicable.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From my inspection sample, I judge the licensee has demonstrated satisfactory implementation of its gas circulator 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 training records for individuals involved in gas circulator examination, inspection, maintenance and testing. I judge that training of these individuals is adequate. Hence, I assigned a Green (No formal action) rating for Licence Condition 10 compliance.
- Licence Condition 23 (Operating rules) – I sampled gas circulator safety case limits and conditions. I judge the operating rules were clearly identified and understood. Hence, I assigned a rating of Green (No formal action) for Licence Condition 23 compliance.
- Licence Condition 24 (Operating instructions) – I sampled gas circulator operating instructions. I judge the operating instructions were included in the licensees document management system. These identify the necessary checks and actions required in the interests of safety. Hence, I assigned a Green (No formal action) rating for Licence Condition 24 compliance.
- Licence Condition 27 (Safety devices, mechanisms and circuits) – I sampled gas circulator safety mechanisms, devices and circuits. I identified shortfalls with demonstration of non-return valve availability and safety classification. I captured this as a level 4 regulatory issue. This requires the licensee to identify non-return valves in the gas circulator system and demonstrate the adequacy of their safety classification. Although I considered the clarity of the safety claims made for the non-return valve merited further exploration, I judged that the licensee was compliant with their own arrangements and therefore considered a Green (No formal action) rating for Licence Condition 27 compliance.
- Licence Condition 28 (Examination, inspection, maintenance and testing) – I sampled the gas circulator plant maintenance schedule. I judge that examination, inspection, maintenance and testing activities were undertaken and supervised by suitably qualified and experienced people using schemes laid down in writing. Hence, I assigned a Green (No formal action) rating for Licence Condition 28.
- Licence Condition 34 (Leakage and escape of radioactive material and radioactive waste) – I sampled the monitoring and disposal of gas circulator waste. I judge that monitoring and disposal of gas circulator waste was adequate. Hence, I assigned a Green (No formal action) rating for Licence Condition 34 compliance.
Conclusion of Intervention
Based on my sampled inspection, I conclude that the licensee has demonstrated adequate gas circulator safety case understanding and implementation.
One level 4 regulatory issue was raised relating to non-return valve safety case claims.