Office for Nuclear Regulation

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MSC13 - Manufacturing Assurance - Start of Manufacturing - Fuel Handling Equipment

Executive summary

Purpose of Intervention

The purpose of this intervention was to assess NNB Generation Company (HPC) Limited’s (NNB GenCo) implementation of its arrangements for carrying out engineering readiness reviews on equipment design packages prior to the release of the start of manufacturing hold point for that equipment.

Interventions Carried Out by ONR

ONR carried out a Licence Condition 17 ‘Management Systems’ intervention related to the release of the start of manufacture hold point for Fuel Handling Equipment. License Condition 17 requires the licensee, within its management systems, to make and implement adequate quality management arrangements for all activities that may affect safety. This includes procurement, design, construction, manufacture and commissioning.

The intervention was carried out by observing the readiness review via Skype after which a follow up meeting was held to discuss observations and raise questions.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

The review was conducted in a professional manner with an atmosphere that encouraged open discussion of technical and project matters. The NNB GenCo Project Manager was not seen to be exerting undue pressure on the other attendees to approve the items on the review checklist. The attendees appeared to be knowledgeable in their respective areas and understood the objectives of the review.

Early in the review NNB GenCo concluded that aspects of the Spent Fuel Mast Bridge design package were not in a sufficiently mature state to warrant further consideration at this point in time. As such, the review proceeded with NNB GenCo considering only the Refuelling Machine. I consider the decision taken by NNB GenCo shows conservative decision making and provides assurance that equipment is not being rushed through the start of manufacture process.

┬áThe status of welding data books for the Refuelling Machine, Spent Fuel Mast Bridge and a pending modification affecting the refuelling machine hoist drum were discussed. NNB GenCo concluded that these items related to specific manufacturing steps and their resolution should not prevent the overall release for start of manufacture subject to hold points being added to the manufacturer’s quality plan for the start of welding and machining of the hoist drum. I consider this to be a pragmatic and acceptable approach which will ensure that start of manufacture is not delayed unnecessarily.

The Quality Management Lead or a representative did not attend the review even though consideration of the adequacy of the quality arrangements is a key aspect of the design package review. NNB GenCo’s guidance documents do not mandate the attendance of specific stakeholders; I will follow up this observation with ONR’s quality inspectors.

I am satisfied that adequate consideration was given to design stability by consideration of open points, status of current modifications, risk of future modifications, status of interfacing design packages, variations and exemption requests.

ONR is particularly interested in establishing that the safety case requirements are appropriately reflected in procurement documentation such that equipment will be designed / manufactured to fulfil these requirements. This was not specifically covered during the review as it is understood to be addressed prior to the placing of contracts. Consideration will be given to a future intervention to sample the relevant parts of the procurement specification for a sample of nuclear significant equipment to gain confidence that the safety case requirements are in fact reflected.

ONR identified a number of areas where further information is required; however provision of the information is not linked to NNB GenCo’s release of the design packages and will be followed up through routine nuclear island topic stream engagements.

The review concluded that the design packages presented were not sufficiently mature for the start of manufacturing of either the Refuelling Machine or the Spent Fuel Mast Bridge. As such, further review will be undertaken by NNB GenCo prior to releasing the start of manufacture hold points.

Conclusion of Intervention

Overall, I am satisfied that NNB GenCo’s implementation of its arrangements for the release of the start of manufacture design packages was adequate. Observing the review provided assurance that the start of manufacture hold point would not be released for the Refuelling Machine and Spent Fuel Mast Bridge until the requirements of the review checklist have been met.

Based on the observations, discussions and evidence from NNB GenCo leading up to and during the review, I consider NNB GenCo’s implementation of its LC17 arrangements for the release of start of manufacture design packages for the Refuelling Machine and Spent Fuel Mast Bridge to be GREEN (no formal action required).