Office for Nuclear Regulation

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Level 4 Fuel, Core and Criticality Meeting

Executive summary

Purpose of intervention

This intervention was one of an ongoing series of level 4 meetings with Nuclear New Build Generating Company (NNB GenCo) in the area of fuel and core design and criticality. The meeting's purpose was to maintain the Office for Nuclear Regulation (ONR) oversight of the licensee's (i.e. NNB GenCo) progress with the development of a robust safety case for the proposed fuel and core designs for the two Hinkley Point C (HPC) reactors, including the criticality safety aspects of all ex-core fuel handling and storage operations. In addition the meeting allows ONR to monitor the licensee's progress in the closure of relevant Generic Design Assessment (GDA) findings.

Interventions Carried Out by ONR

The intervention was a planned intervention under the currently extant intervention project record and was carried out under Licence Condition (LC) 23 ("operating rules"), as the focus of this intervention is on the licensee's progress in developing of its safety case in these important technical areas. My intervention was conducted via a face-to-face meeting with key NNB GenCo staff (the licensee's own internal regulator and an inspector from the Environment Agency also attended the meeting). The licensee provided a series of good quality presentations and discussions were then held around these presentations.

Explanation of Judgement if Safety System Not Judged to be Adequate


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

The standards I have used to judge the licensee's work to date, in the fuel and core and criticality areas, are those defined by ONR's Safety Assessment Principles (SAP) and in particular SAPs ERC.1 - ERC.4 and ECR.1 and ECR.2. From the information presented by the licensee at the meeting I judge that:

In my opinion the licensee is able to evidence ongoing adequate execution of its intelligent customer (IC) role in these technical areas.

Progress with production of Resolution Plans (RP) for GDA findings was discussed and although few RPs have been produced to date in the fuel/core/criticality areas and little work is planned for the rest of 2014, I am broadly content with the position given the nature of the findings, the information required to close them and the back end loading of the technical areas.

A detailed discussion was held on secondary neutron sources (whether or not these will be used at HPC), which provided some useful background as to why the RP had been quite scant for this GDA finding (i.e. as the RP references a 'Commitment Plan' which is a lot more detailed). I judge that adequate progress is being made with respect to this GDA finding.

An update was provided on fuel and core design and on the status of the fuel contracts and I am content that work in this area is at an acceptable position.

The licensee presented a detailed discussion of its potential future reload safety case strategy. The work being undertaken by the licensee in this area appears to me to be both proactive and pragmatic and the licensee is trying to work towards reload safety cases that drastically reduce the production time for this safety case in comparison to Sizewell B (SZB), whilst recognising that it will remove some flexibility with respect to future core design. Good use is being made of French and other international operating experience (OpEx) - noting that the French approach does not permit flexibility in core design - in pursuing the goals in this area. Whilst quite a lot of work remains to be done, the work to date appears promising and the licensee was able to highlight the work remaining. It is hoped that for the UK EPR the safety case strategy will not unduly compromise the desired flexibility in core design.

In the criticality safety area of the HPC design, the licensee has struggled a little in identifying a single point of contact within the Responsible Designer (RD) organisation in France. This difficulty appears to have been largely resolved and a specification of the full scope of the criticality analysis work required of the RD has now been produced and presented. Work should hence accelerate in this area in the near future.

Conclusion of Intervention

As has been the case for all level 4 meetings to date in these technical areas, the licensee's presentations were of a good quality and the meeting was conducted in a very open and transparent manner. I was given ample opportunity to ask questions of the licensee and was given what I judged to be thorough answers to the questions. The licensee continues to make good progress across the technical areas under consideration and the work appears to be being adequately integrated into the project safety case deliverables (although I note some work is ongoing in this area). The focus on the execution of the intelligent customer role appears good and in my opinion the licensee was also able to evidence some good proactive work for the future in the fuel and core area.

After a somewhat slower start, I judge that the licensee now has a good grasp as to what it requires of its overall fuel route criticality safety case and I expect work in this area to begin to accelerate.