Office for Nuclear Regulation

This website uses non-intrusive anonymous cookies to improve your user experience. You can visit our cookie privacy page for more information, including details on how to opt-out.

Heysham 2 Reactor 7 2015 Periodic Shutdown: Graphite Core Inspection

Executive summary

Purpose of intervention

Heysham 2 Reactor 7 began its periodic shutdown on 27th February 2015 as part of the licensee’s, EDF Nuclear Generation Limited’s, compliance with Licence Condition (LC) 30.  During the shutdown the licensee will perform examination, maintenance or testing of plant; in particular that required by the Maintenance Schedule which includes the graphite core.

Purpose of Intervention

I performed an intervention at Heysham 2 power station on 10th March 2015.  The purpose of the intervention was to inspect the adequacy of the licensee’s examinations and inspections of the graphite core and determine compliance with LC 28(1).

Interventions Carried Out by ONR

 I carried out the following interventions as part of my inspection:

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

The graphite inspection programme identifies 16 channels for visual inspection and dimensional measurement and one control rod channel for visual inspection.  5 of those channels have been scheduled for trepanning, 7 samples from 4 channels and a further 8 from the remaining channel.  I judge that if successful, this programme will satisfy the Maintenance Schedule requirements of 16 channel inspections, 1 control rod channel inspection and removal of 24 samples from the core.

Inspection of channel R27 had been completed at the time of my intervention and a small part circumferential defect had been observed.   This defect had been observed previously in 2008 and had not grown.  I judged that the defect was minor and did not challenge the safety case.

The graphite core inspection equipment had undergone inspection by an independent competent person and I judged the equipment was compliant with the Lifting Operations and Lifting Equipment Regulations 1998.  Improved maintenance and equipment configuration arrangements had been put in place to improve the reliability of the inspection equipment.  These arrangements appeared adequate.

Nuclear Generation Limited had provided a comprehensive programme of training in the use and operation of NICIE 2 graphite inspection equipment.  I spoke to a member of staff to confirm attendance at the training and inspected his training record.  Based on the conversation I had and the records provided, I judge that the member of staff had completed adequate training. 

Conclusion of Intervention

Based on the observations made during my intervention I am of the opinion that the licensee’s initial examinations and inspections of the graphite core were adequate.  I Have therefore allocated an IIS rating of 3.  I consider that the licensee had demonstrated compliance with LC 28(1).

At the time of the intervention, the schedule of graphite core inspections, as defined by the outage intent document, had not been completed.  When the inspection schedule has been completed to the satisfaction of the safety case requirements, an assessment report will consider whether the results are consistent with the graphite core safety case.

I recommend that the relevant project inspector, who will be writing the project assessment report, considers this forthcoming assessment report.  Its conclusion will help to inform their decision as to whether to recommend that Consent to return to service is granted.