Executive summary
Date(s) of inspection:
Aim of inspection
The aim of the inspection is to consider Dounreay’s nuclear ventilation systems to confirm that their conditions and operations are in line with established relevant good practice. The inspection will also seek to confirm that ventilation projects undertaken at Dounreay are being conducted in line with expectations.
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
A team of ONR inspectors including fault analysis and mechanical specialist inspectors conducted a systems-based inspection, focusing on the ventilation systems within Dounreay’s Fuel Cycle Area (FCA), using the guidance in ONR-INSP-GD-059 Issue 8.2. This included detailed consideration of the main FCA ventilation systems (D1209) and the D2670 facility ventilation systems; as well as consideration of projects to design and install a new ventilation system at Dounreay Cementation Plant Store Extension 2 and the D1203 facility ventilation upgrade project.
The dutyholder representatives presented a summary of the FCA ventilation systems, including a system overview highlighting the safety, environmental, and operational claims made on the system, and the improvements made since commencement of operation of the system in 2009. I found the dutyholder’s team competent, able to explain how the safety case had been implemented, and able to readily answer questions relating to their arrangements. I could link the protection systems designated within the safety case through the engineering schedule to those on plant. I also saw evidence that safety case requirements were specified in maintenance practices / instructions. I therefore rated LC23/24 as GREEN (No Formal Action).
Evidence was provided that safety equipment was available and subject to an appropriate Examination, Inspection, Maintenance and Testing regime. There was evidence provided that asset condition was being monitored and that where environmental conditions had resulted in asset degradation, action had been taken to modify the system to better manage the associated environment. I therefore rated LC27/28 as GREEN (No Formal Action)
During this inspection, the dutyholder demonstrated the measures in place to control leakage and escape of radioactive material from redundant ductwork, as well as the control and monitoring of filtration on the ventilation systems. Based on the sample inspected I judge that the dutyholder has adequately demonstrated relevant good practice, in accordance with LC34. I therefore rated this aspect of the inspection as GREEN
I examined the training system that the dutyholder maintains, and I found clear evidence that the dutyholder has systematically identified the competencies required for performing roles related to the ventilation systems inspected. I sampled the training records for an operator, a mechanical supervisor, and an operational manager; based on the sample inspected I judge that the dutyholder has adequately demonstrated relevant good practice, in accordance with LC10. I therefore rate LC10 as GREEN (No Formal Action).
The inspection sampled two ventilation projects on the site: Dounreay Cementation Plant Store Extension 2 and the D1203 facility ventilation upgrade project. Both these projects appear well managed and employing appropriate standards.
Conclusion
This was a wide-ranging review of multiple facilities at differing points in their respective lifecycles, and the inspection outcome was made easier by the preparedness and openness of the dutyholder representatives. I have made my regulatory judgement against each of the Licence Conditions (LCs) covered by ONR guidance (ONR-INSP-GD-059 Issue 8.2). Each aspect of this systems-based inspection was rated as GREEN, and my overall judgement for this inspection is GREEN (No Formal Action).