- Site: Sizewell B
- IR number: 21-088
- Date: October 2021
- LC numbers: 28
Executive summary
Purpose of Intervention
The purpose of this intervention was to conduct an ageing management inspection of EDF Energy Nuclear Generation Limited (EDF NGL) Sizewell B (SZB) power station. In 2021-22, the Office for Nuclear Regulation (ONR) is carrying out a Chief Nuclear Inspector’s (CNI) themed inspection on the management of ageing assets. This comprises a series of inspections across nuclear site Licensees, the purpose of which is to seek evidence of sustainable programmes for the management of ageing assets against four themes: monitoring of ageing, organisational capability, obsolescence, and ongoing investment. This inspection was conducted between 5th and 7th October 2021 and covered themes one and three, monitoring of ageing and obsolescence. The implementation of ageing management arrangements for both security and safety were inspected.
Interventions Carried Out by ONR
An ageing management inspection was performed and rated against Licence Condition 28 (LC28) Examination, Inspection, Maintenance and Testing. Preventative maintenance was prioritised for examination during the inspection. The purpose of LC28 is to ensure that the licensee makes and implements adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety. Ageing management arrangements are included within the scope of arrangements necessary to demonstrate compliance with LC28.
Plant walkdowns of the following systems were conducted during the inspection:
- The Condensate Storage Transfer System
- Reactor Protection System
- Perimeter Intruder Detection System
The focus of the inspection was to establish if EDF NGL’s arrangements are adequately implemented to detect the onset of equipment degradation, and also to quantify the extant material condition and the rate of ageing of safety and security significant plant. The inspection sampled EDF NGL’s arrangements for ageing management and their implementation for the systems under consideration. The inspection included discussions with various responsible members of EDF NGL staff. Principally, this included system engineers, senior management, and Independent Nuclear Assurance Inspectors.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Overall, it was concluded that the arrangements for ageing management had been adequately implemented in line with ONR’s expectations and good examples of proactive ageing management of plant were provided.
During the course of the inspection, areas of potential improvement were explored, however no formal regulatory issues were identified. The Control and Instrumentation Ageing and Obsolescence training had been delivered on initial roll out. However, this item of training had not been recorded on the Sizewell B training matrix, and hence repeat occurrences had not been scheduled. The Licensee immediately raised a training request to address this omission, and hence I judged that no further regulatory intervention was necessary with respect to this matter.
EDF NGL demonstrated implementation of proactive obsolescence management arrangements, including long term support contracts and the implementation of propriety tools. These arrangements have wide coverage across the systems and facilitate access to industry wide knowledge, thereby enabling changes in the supply chain to be managed in a controlled way. I judge proactive obsolescence management at SZB to be an area of good practice.
SZB has retained and maintained the original equipment qualification cabinets for the primary protection system. These cabinets allow ageing mechanisms to be observed and understood; identify whether there are cliff edge effects beyond design life; and enable component testing and staff training. I judge that the retention and maintenance of these qualification cabinets is an area of good practice.
Conclusion of Intervention
I judged from the evidence sampled that EDF NGL are effectively monitoring ageing and managing obsolescence of SZB power station. I have therefore assigned an inspection rating of Green (no formal action) against LC28.