Office for Nuclear Regulation

Hinkley Point C - Licence condition 19 compliance inspection CD15 - Pre Cast Concrete

Executive summary

Purpose of Intervention

In accordance with the Office for Nuclear Regulation’s (ONR’s) Hinkley Point C Construction Inspection Plan, ONR performs a series of planned compliance inspections of identified licence conditions. This is to ensure that the licensee, NNB Generation Company (HPC) Ltd (NNB GenCo), is adequately developing and implementing its licence condition compliance arrangements in a manner that is commensurate with the stage of the project under consideration.

This intervention was an inspection carried out to assess NNB GenCo’s compliance with licence condition 19 (LC19); Construction or Installation of New Plant. LC19 requires that where the licensee proposes to construct or install any new plant, which may affect safety, the licensee makes and implements adequate arrangements to control the construction or installation.

This intervention was led by the inspector responsible for ONR’s civil engineering construction assurance (CECA) and sought to assess NNB GenCo’s application of relevant good practice in the area of pre-cast concrete construction in the permanent works.

Interventions Carried Out by ONR

This intervention sought to assess NNB GenCo’s application of relevant good practice in the area of construction planning for the precasting activities for the nuclear island structures of both Unit 1 and Unit 2. This was a formally rated intervention.

The nuclear island structures have been designed to act monolithically. The introduction of precasting for elements of superstructure introduces risks to structural performance allied principally to the connections between elements. Such risks are known in the industry. Noting the intrinsic advantages of precasting, ONR takes a proportionate regulatory interest in such a proposal.

The purpose of this intervention was to enable ONR to gain oversight of the construction planning activities for the following purposes:

The physical precasting operations covered by this intervention had not commenced at the time of this intervention. The principal emphasis of the intervention was on the application of relevant good practice in the management and planning of construction operations. No physical inspection was carried out at site.

Explanation of Judgement if Safety System Not Judged to be Adequate

This section is not applicable as this was not a safety system inspection.

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

The intervention was well managed and NNB GenCo planned for attendance by the appropriate personnel. Responses to questioning were forthcoming, informative and provided me with confidence that the planned operations were being adequately managed, with due consideration of the risks involved.

Overall, I was satisfied that the licensee’s current arrangements in relation to the planning of implementation of precast concrete construction. A small number of actions were raised aimed at clarifying certain points of interest identified during the intervention. These are judged not to be of sufficient seriousness to affect the intervention rating and as such, do not warrant the raising of an associated regulatory issue.

Conclusion of Intervention

On the basis of the evidence sampled, I was satisfied that the proposed arrangements met relevant good practice. I judge that an inspection rating of GREEN (No formal action) is appropriate for this intervention. No level 4 regulatory issues were raised.