Office for Nuclear Regulation

Oxygen Inspection readiness inspection - Human Factors

Executive summary

Purpose of Intervention

The purpose of this inspection was to assess the readiness of EDF Heysham 1 and BOC personnel to commence blended oxygen / carbon dioxide injection at the Heysham 1 site.  The purpose of this activity is remove carbon deposits on the fuel and thus reduce fuel failure rates. The intervention scope was limited to Human Factors (HF). 

The inspection was undertaken on the 3rd October 2019 and is the final inspection of a series of multi-disciplinary inspections undertaken to inform ONR’s permissioning of this activity.  It follows two previous HF inspections: a factory acceptance test inspection performed at BOC and a previous readiness inspection at Heysham 1 which included HF elements.

Interventions Carried Out by ONR

The scope of the inspection is summarised below. 

Explanation of Judgement if Safety System Not Judged to be Adequate


Key Findings, Inspector's Opinions and Reasons for Judgements Made

The key findings from this inspection comprise:

Conclusion of Intervention

To conclude, I judge that EDF and BOC have demonstrated that the risk from Human Error appears suitably controlled so far as is reasonably practicable. EDF will consider implementing the identified enhancements to the procedures and pre-job brief for future injection activities. These enhancements will be tracked by EDF’s internal regulator.


I have made three minor recommendations are made to enhance the usability of the operational procedures and the efficacy of the pre-job briefs for any potential future injection campaigns. These recommendations do not impact on the current campaign.