This was a planned inspection at EDF Nuclear Generation Limited's Heysham 1 Power Station, undertaken as part of the planned intervention strategy for the Civil Nuclear Reactor Programme.
The key intervention carried out by the nominated site inspector was a licence condition (LC) compliance inspection of LC28, examination, inspection, maintenance and testing.
The nominated site inspector reviewed the company LC28 procedures and subsequent compliance against the relevant ONR guidance document. Although the maintenance procedures covered a number of key maintenance aspects, a number of areas for improvement were raised with the Licensee. These related to the easy identification and interaction of these numerous procedures, guidance on sentencing of maintenance tasks to the LC28 maintenance arrangements and guidance for determining the maintenance periodicity to ensure that the safety case requirements are met.
A number of maintenance items have been deferred into their tolerance band and are close to the tolerance limit or have had their periodicity extended by engineering change. This combined with the number of instances where equipment has failed shortly after maintenance, or has been returned to service in the incorrect configuration, indicates that the station are not operating at the expected standard for compliance with LC28. Consequently this intervention against LC28 was rated as below standard.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
ONR has raised similar concerns with maintenance in the past and, although improvements were initially made to reduce the number of maintenance items in their tolerance bands, the number of items has started to rise again. In light of this, I will be writing to the Licensee seeking a recovery plan to deliver the necessary improvements. ONR will then monitor this plan to ensure that the necessary improvements are achieved in a timely manner.