Office for Nuclear Regulation

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Mechanical Inspection of Reactor 4 period shutdown

Executive summary

Purpose of intervention

This was a planned inspection of EDF Energy Nuclear Generation Ltd’s (NGL’s) Hinkley Point B power station, undertaken as part of the planned intervention strategy for the Civil Nuclear Reactor Programme (CNRP) of the Office for Nuclear Regulation (ONR).

The work was carried out in line with the planned inspection programme contained in the Hinkley Point B Integrated Intervention Strategy (IIS).

Interventions Carried Out by ONR

A Control and Instrumentation (C&I) inspector and I (the nominated site inspector for Hinkley Point B) carried out a System Based Inspection (SBI) of the instrument air system and turbine over speed protection.

I carried out a compliance inspection on LC21 (commissioning), met with the internal regulator and held information gathering meetings with NGL.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

The instrument air system and turbine over speed protection was judged to meet the requirements of the safety case and was adequate.

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

The ONR team carried out a system based inspection of the instrument air system and concluded that:

I carried out a compliance inspection of LC21 (commissioning) on the new Nitrogen plant on site and concluded that good processes were in place to provide assurance that the commissioning and testing activities were being addressed.  Responsibilities within the project were understood and staff had been appointed into key roles.  Appropriate safety committees had been established and commissioning was in progress.  I assigned an IIS rating of - 2 (good) to this inspection.

I met with the site internal regulator to discuss recent events, on-going inspections and future intervention topics.  I held information gathering meetings with station staff on a range of topics including plant status, the recent failure of a section of Nitrogen pipework, the revision of the Technical Specification relating to the kerosene storage tanks and a number of site safety initiatives.

Conclusion of Intervention

From the evidence sampled during the SBI inspection against LCs 10, 23, 24, 27, and 28 for the instrument air and turbine overspeed protection, we consider that the requirements of the safety case have been adequately implemented at Hinkley Point B.

For LC21 (commissioning) I was satisfied that good processes were in place to provide assurance that the commissioning and testing activities on the site were being well managed. 

There are no findings from this inspection that could significantly undermine nuclear safety.