Office for Nuclear Regulation

Hinkley Point B - Plant material condition

Executive summary

Purpose of Intervention

The purpose of this intervention was to conduct an inspection to establish the adequacy of arrangements implemented under the site corrosion management programme. The work was carried out as part of the Office for Nuclear Regulation (ONR) planned intervention task sheet TS027 – “Management of Corrosion - Concealed and Buried Systems” and task sheet TS023 – “Management of Storage Tanks and Vessels”.

I carried out this inspection accompanied by the ONR Hinkley Point B site inspector and two additional Inspectors within the Structural Integrity specialism. The inspection took place from the 9th to the 12th of July 2019, and involved discussions with a number of EDF Energy Nuclear Generation Limited’s (NGL) employees responsible for the operation and safety of the plant. A targeted plant walk down of the systems selected for sampling was also undertaken.

Interventions Carried Out by ONR

The primary aim of the inspection was to perform a review the adequacy of the licensee’s arrangements for managing plant material condition of storage tanks and buried pipework that are important for safety, against the requirements of licence condition (LC) 28 – Examination, Inspection, Maintenance and Testing (EIMT).

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

From the information that I have sampled I judge that the corrosion management programme at HPB is adequately managed and a good understanding of corrosion degradation could be demonstrated. Some good progress has been made at Station in addressing the corrosion issue and the current status appears to be in line with the NGL’s plans. 

There remain a number of outstanding corrosion related activities and these are planned to be completed during 2019.  This includes completion of CV3 and CV4 corrosion management tasks, implementation of appropriate maintenance schedules and training as well as the remediation of several systems. 

ONR’s sampling of the maintenance schedule related to the Auxiliary steam system and the diverse shutdown system appeared to show Pressure System Safety Regulation (PSSR) driven inspection requirements.  It was not evident how these ensured that the system complied with the safety case requirements and so adequately satisfied Licence Condition 28 requirements for Examination, Inspection, Maintenance and Testing.  

Conclusion of Intervention

I judge that, against the requirements of LC28, a rating of AMBER in accordance with ONR inspection rating guidance (CM9 2016/118606) is appropriate. This is based on the shortfalls identified in the systematic approach to the Maintenance Schedule related activities, which appeared to show a PSSR-led approach across the two sampled system.  Consequently, I have raised one Level 4 Regulatory Issue for the licensee to demonstrate the adequacy of its systems and processes to ensure nuclear safety.