SBI 28, Shutdown Systems - Control Rod System and LC4 Compliance Inspection
- Site: Heysham 2
- IR number: 17-130
- Date: October 2017
- LC numbers: 4
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 receipt of nuclear fuel
- the storage of new and irradiated fuel
- records relating to the receipt, storage and movement of new and irradiated fuel
- Heysham 2 compliance against its technical specification limits and conditions
- Inspection of the fuel storage facilities
The LC4 inspection undertaken utilised the following ONR guidance documents:
- LC4 - NS-INSP-GD-005 - Restrictions on nuclear matter on site
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:
- LC10 Training - a number of training records were sampled and examined from individuals identified during the control rod maintenance facility walkdown. All but one was found to be suitably qualified and experienced for the roles and tasks being undertaken. The one individual who was identified as not having completed one element of the identified training requirements for the role. However on investigation the individual was found to be booked to attend the appropriate training. The licensee commented that the particular training package was not considered critical to the role. I was content with station's explanation response and therefore considered an ONR inspection rating of Green to be appropriate.
- LC23 Operating Rules - Limits and conditions of operation were specified through station Technical Specifications. These ensure that under the specified conditions of operation, sufficient shutdown and holddown margin is achieved together with unavailability limits on control rods as required by the safety case. I was content with the evidence sampled that the licensee fulfils these requirements. I therefore judged that an inspection rating of Green was warranted
- LC24 Operating Instructions - I sampled and examined a number of operating instructions associated with the reactor shutdown margin and sensor rod testing. These were specified in a technical specification compliance schedule. I sampled a number of these and was content that operations were controlled in accordance with them. I therefore judged that an inspection rating of Green was warranted
- LC27 Safety Mechanisms, Devices and Circuits - the licensee demonstrated that appropriate checks were undertaken ensuring that operations were not undertaken unless an appropriate number of control rods and holddown margin had been determined. Insertion times of control rods were also regularly checked. I judged that this warranted an inspection rating of Green.
- LC28 Examination, Inspection, Maintenance and Testing - the licensee demonstrated that there are adequate processes, procedures and records in place for the examination, inspection, maintenance and testing of plant important to safety. The sampled documentation showed that suitable records had been produced for maintenance activities. During the plant walkdown, I observed a control rod drop test during which I noted a limitation with the testing instrumentation and the maintenance instruction requirements. In light of this I have raised a regulatory issue in order to follow the station's progress in resolving it. This is a minor issue and does not undermine nuclear safety. I have therefore judged that an inspection rating of Green was warranted
- For the LC4 compliance inspection, I examined the arrangements for management of nuclear fuel and organisational responsibilities are auditable and I identified a clear link from the company arrangements to the station's departmental instructions. I verified that these documents adequately cross-reference against other licence condition compliance arrangements that underpin Fuel Route movement activities including LC6 (Document records, authorities and certificates), LC17 (Management Systems), LC25 (Operational Records) and LC12 (Duly authorised and other suitably qualified and experienced persons).
- I identified a minor administrative non-compliance for the station's arrangements for LC12. No role profile associated with the work undertaken by the Operational Planning Engineer was available although the role profile was currently being developed by the station. I have therefore raised a regulatory issue in order to track the station's progress in regards to this. I have therefore rated the LC4 compliance inspection as Green.
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.