Hinkley Point B - SBI 22 inspection
- Site: Hinkley Point B
- IR number: 18-194
- Date: January 2019
- LC numbers: 10, 23, 24, 27, 28, 34
Purpose of Intervention
The main purpose of this intervention was to conduct a system based inspection (SBI) of EDF Energy Nuclear Generation Ltd.’s (NGL) Hinkley Point B Power Station (HPB) in relation to the CO2 storage and distribution system.
This intervention was undertaken as part of a series of planned interventions that are listed in the Hinkley Point B Integrated Intervention Strategy 2018/2019. The inspections were undertaken by the ONR nominated site inspector and two ONR nuclear specialist inspectors for structural integrity, which for the purpose of this intervention report shall be referred to as “I”.
Interventions Carried Out by ONR
I performed a safety case informed SBI of the CO2 storage and distribution system. Through examination of these systems, compliance inspections were performed against the following Licence Conditions (LC):
- LC10 (Training);
- LC23 (Operating Rules);
- LC24 (Operating Instructions);
- LC27 (Safety Mechanisms and Devices);
- LC28 (Examination, Inspection, Maintenance and Testing); and
- LC34 (Leakage and Escape of Radioactive Material and Radioactive Waste).
The objective of the inspection was to determine whether the licensee’s arrangements were adequately implemented and in accordance with the systems’ safety case requirements. These inspections were informed through the review of the station safety report (including supporting documents and references), discussion with station specialists, plant inspection and sampling of electronic documents and records. During normal operations, the CO2 plant provides a supply of CO2 to the reactors and various fuel route facilities to maintain reactor pressure and to facilitate fuel route operations. During fault conditions, the CO2 plant is part of an overall line of protection for various reactor and fuel route faults.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Explanation of Judgement if Safety System Not Judged to be Adequate
From the system based inspection, I judge that overall the CO2 storage and distribution system meets the requirements of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Based on the areas sampled during this system based inspection, I consider that Hinkley Point B has implemented suitable arrangements to ensure that the CO2 storage and distribution system is maintained and operated in accordance with the safety case and the station’s arrangements.
In summary, the outcome of the SBI of the system was as follows:
- I was satisfied, on the basis of discussions with a range of relevant staff, that Hinkley Point B has implemented its arrangements for training staff with responsibilities for the specific operation and maintenance of the system. I consider that, based on the evidence seen during this intervention, that an inspection rating of ‘Green – no formal action’ is appropriate for LC10.
- I was satisfied that the safety case limits and conditions have been identified and where necessary have been incorporated into technical specifications. I consider that, based on the evidence seen during this intervention, that an inspection rating of ‘Green – no formal action’ is appropriate for LC23.
- I was satisfied that operating instructions were in place to support plant operations. I consider that, based on the evidence seen during this intervention, that an inspection rating of ‘Green – no formal action’ is appropriate for LC24.
- I was satisfied that suitable and sufficient safety mechanisms, devices and circuits (LC27) were connected and in working order with identified operating limits and condition’s to meet the requirements of the safety case. I consider that, based on the evidence seen during this intervention, that an inspection rating of ‘Green – no formal action’ is appropriate for LC27.
- I have observed that the system was maintained appropriately meeting requirements of LC28 and on that basis have assigned an IIS rating of ‘Green – no formal action’ against the LC28 element of this system based inspection.
- I was satisfied that the systems were appropriately meeting requirements of LC34 and on that basis have assigned an IIS rating of ‘Green – no formal action’ against the LC34 element of this system based inspection.
Conclusion of Intervention
After considering all the evidence examined during the sample inspection undertaken against LCs 10, 23, 24, 27, 28 and 34 I judged that the requirements of the safety case have been adequately implemented at Hinkley Point B, with a rating of ‘Green – no formal action’ assigned against licence conditions 10, 23, 24, 27, 28 and 34.
There were no findings from this inspection that could significantly undermine nuclear safety. However, during my inspection following two minor shortfalls were identified:
- NGL were unable to demonstrate the link between the specified maintenance intervals for the CO2 distribution pipework and the safety case requirement. I have therefore raised a Level 4 regulation issue (6983) to address this shortfall and have requested that NGL demonstrate how the safety case reliability requirements for the CO2 distribution pipework and CO2 storage vessel safety valves are supported by the maintenance programmes. In areas sampled, I consider that inspections beyond those specified in the maintenance schedule requirements are currently being undertaken for the distribution pipework and so am therefore content that there appears to be no immediate risk to nuclear safety since appropriate inspections have been undertaken.
- The CO2 system owner ‘post and training’ profile requires the engineer to act as a subject matter expert in plant areas as designated, however, NGL were unable to explain how this requirement was demonstrated in the training of new personnel in this role. Subsequent enquiries following my inspection has identified that this particular issue has previously been captured under Regulatory Issue 6494 by an ONR Leadership for Management of Safety Inspector requesting the fleet-wide development and implementation of a system handover pack standard (with Stations and Group Heads involved) together with an associated framework to demonstrate System Engineers are suitably qualified and experienced for their systems. Currently, NGL commitments to address this action are ongoing with anticipated completed date of June 2019. Consequently, I consider that no further action is warranted in this instance.