Office for Nuclear Regulation

Hinkley Point B - Structural Integrity Inspection

Executive summary

Purpose of Intervention

This is a record of an intervention by the Office for Nuclear Regulation (ONR) at Hinkley Point B Power Station (HPB) during the 2018 Reactor 4 (R4) periodic shutdown. The purpose was to inspect work by the licensee, EDF Energy Nuclear Generation Limited, to comply with Licence Condition 28 (LC28), examination, inspection, maintenance and testing (EIMT).

Interventions Carried Out by ONR

I met with licensee staff and their contractors to examine compliance with Licence Condition 28. I concentrated on aspects of structural integrity that I judged important to nuclear safety.

I sampled aspects of the inspection programme undertaken during the periodic shutdown on the steam and feed systems and other safety related systems external to the reactor pressure vessel. NGL have previously produced a safety case to justify the deferral of vessel entry inspections at this outage, therefore no inspections took place on the metallic components internal to the reactor pressure vessel.

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

I found satisfactory progress of planned EIMT by the time of my visit. Of 410 components in the programme, 177 were not started, none in grinding, 28 in progress, eight in referral, none repaired and 197 complete.

I have of sampled aspects of the following:

I have found evidence of satisfactory EIMT for each of the above. Some notable findings are as follows:

During an outage assessment panel meeting I observed sentencing of inspection results and found these reasonable. I undertook a plant walkdown, from which no significant adverse findings resulted.


Based on evidence sampled, I conclude the licensee has performed adequate EIMT to satisfy LC28. I award an inspection rating of green, based on ONR guidance.

EIMT work planned by the licensee during the periodic shutdown was not complete by the end of my inspection. I will monitor further progress and provide my judgement regarding return to service in my assessment report.