Office for Nuclear Regulation

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SBI 28, Shutdown Systems - Control Rod System and LC4 Compliance Inspection

Executive summary

Purpose of Intervention

The purpose of this intervention was to conduct a system-based inspection (SBI) of the control rod shutdown system and to undertake a Licence Condition (LC) compliance inspection of LC4 (restrictions of nuclear matter on the site) at EDF Energy Nuclear Generation Ltd's Heysham 2 nuclear power station. The inspection was done as part of ONRs series of planned interventions as set out in the Heysham 2 integrated intervention strategy for 2017/18.

The inspection was undertaken by the nominated site inspector and was supported by a specialist mechanical engineering inspector. The inspection was also attended (one day only) by a specialist conventional health and safety inspector, who attended in order to gain regulatory experience of an operational reactor.

Interventions Carried Out by ONR

I, the nominated site inspector, carried out a safety case informed SBI of the control rod shutdown system. ONR's SBI examines evidence to determine compliance against six key licence conditions (LCs). The LCs have been selected to provide a structured approach to determine whether the safety case requirements of the system being inspected (in this case control rods) are adequately implemented. The license conditions are: LC10 (training), LC23 (operating rules), LC24 (operating instructions), LC27 (safety mechanisms, devices and circuits), LC28 (examination, maintenance, inspection and testing) and LC34 (leakage and escape of radioactive material and radioactive waste - for this SBI it was considered not applicable).

As part of this inspection, I also undertook a Licence Condition 4 compliance inspection relating to restrictions on nuclear matter on site. I sampled the station licence compliance arrangements and their implementation relating to:

The LC4 inspection undertaken utilised the following ONR guidance documents:

I also undertook an information exchange meeting with the Heysham 2 Independent Nuclear Assurance inspector as part of our quarterly progress update.

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

For the SBI, Heysham 2 nuclear power station demonstrated that it has arrangements in place to ensure that the control rod shutdown system is inspected, maintained and operated in accordance with its safety case. The following LC findings are provided:

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

Conclusion of Intervention

For the SBI element of my intervention, after considering all the evidence presented by the licensee, I consider from my sample examination that the arrangements and their implementation, associated with the control rod shutdown system met the requirements of the safety case. One ONR issue was raised, given that this is a minor non-compliance, I have rated this inspection as Green.

For the LC4 compliance element of my inspection one ONR issue was raised, given that this is a minor administrative non-compliance, I consider that a Green rating is warranted.

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