Office for Nuclear Regulation

Oldbury Nuclear Licensed Site Planned System Inspection and Meetings

Executive summary

Purpose of intervention

I undertook a system inspection of Oldbury’s fuel-free verification process against the safety case.   

I also discussed Oldbury’s progress with preparations for receiving and exporting IONSIVs from other Magnox nuclear licensed sites and progress with the transition plans for the move from defuelling to decommissioning.

Interventions Carried Out by ONR

Oldbury provided me with the safety case used to plan the fuel-free demonstration.  They explained to me how this safety case was in the main the one used throughout defuelling with minor modifications where appropriate for checking that no fuel was present in unusual positions within the reactors and the pond.  I witnessed a channel being emptied of fuel and what happened when an element was left in the channel.  I discussed Oldbury’s preparations for inspecting the bottom of the pond for fuel element debris.

During the visit I also discussed preparations for changing the management structure at Oldbury once the site is declared fuel free.

Explanation of Judgement if Safety System Not Judged to be Adequate

I judged the safety system for fuel-free verification to be adequate.

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

The people working to demonstrate Oldbury is fuel-free will be undertaking tasks in the same way as they did for defuelling the reactors.  As such I judge that there will be a minimal need for additional training.  I witnessed the way that the defuelling operating rules and operating instructions were applied to removing fuel from a channel.  As part of this work the defuelling team deliberately left a fuel element in the channel, so I was able to see how this was registered on the warning safety mechanisms and instrumentation and recorded on paper.  I did not specifically inspect against the maintenance schedule, but noted that the flask crane was to be taken out of service for its maintenance period the week after the inspection.  Part of the fuel-free verification process is to remove absorbers from fuel channels to ensure there is no fuel in them.  History had taught Oldbury that the absorbers may be covered in graphite dust.  To minimise the spread of this dust (and therefore potential leakage and escape) the reactors were to be placed under negative pressure and a special skirt fitted around the bottom of the defuelling machines. These findings provided me with evidence that the systems used to confirm the fuel free status of the site were adequately implementing the fuel-free safety case. 

My discussions on IONSIVs’ transfer to and export from Oldbury indicated that Oldbury was at an early stage in the process.  I reminded the staff of the need to comply with the relevant licence conditions during the work.

I found that Oldbury was well advanced in its planning for the site’s transition from a defuelling site to a decommissioning site.

Conclusion of Intervention

Oldbury demonstrated to me that they were minimising the risks to the public, workers and the environment in their preparations for and work on demonstrating the site will be fuel-free.