Office for Nuclear Regulation

Heysham 2 - SBI02 Inspection

Executive summary

Purpose of Intervention

This was a planned inspection of EDF Energy Nuclear Generation Ltd’s (NGL’s) Heysham 2 power station, undertaken as part of the planned intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR).

The work was carried out in-line with the planned inspection programme contained in the Heysham 2 Integrated Intervention Strategy (IIS).

Interventions Carried Out by ONR

We performed a safety case informed System Based Inspection (SBI) of the Data Processing and Control System (DPCS) against its safety function. The function of DPCS is to provide prompts for operator action (i.e. protection) in conjunction with separate hard wired alarms and indications; and to ensure that in normal operation the plant remains within the operating envelope of the reactor. Through examination of the system, a compliance inspection was performed against the following License Conditions (LCs) which are applicable provisions of the Energy Act 2013 (Note: LC34 (Leakage and escape of radioactive material and radioactive waste) which is usually considered during a SBI was not considered applicable to this intervention.)

The inspection was undertaken by a control and instrumentation (C&I) specialist inspector and two human factors specialist inspectors. For training purposes a C&I specialist nuclear associate also participated in the inspection. The inspection was based on discussions with staff, a plant walkdown, and sampling of documentation of the implementation of the licensee’s arrangements against the LCs. The objective of the inspection was to determine whether the licensee’s arrangements were adequately implemented and in accordance with the system’s safety case requirements.

In conjunction with the inspection against the LCs mentioned above, an inspection of the physical, procedural and technical security controls of the DPCS was undertaken by a specialist security inspector from the ONR Civil Nuclear Security division. The details of this inspection are captured in a separate intervention record (ONR-CNS-IR-18-034).

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 this inspection, we judged that overall the safety provisions applicable to the DPCS met the requirements of the safety case.

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

In general, during the course of this SBI, it was found that Heysham 2 has adequate arrangements in place to ensure that the DPCS is inspected, maintained, and, as necessary, operated in accordance with the safety case. The arrangements examined complied with the licensee’s legal duties based on the areas sampled during the inspection.

We observed a shortfall in the clarity of the safety role of the DPCS with different documents providing disparate and in some cases contradictory statements on the role of the DPCS. We placed actions on the licensee to clarify the safety role of the DPCS and the interactions and connections it has with other systems. Additionally, an action was placed on the licensee regarding the provision of explicit acceptance criteria required to ensure operating rule compliance. We placed a further action on the licensee to review and update the asset management system such that accurate data is captured regarding DPCS spares. These actions resulted in a level 4 regulatory issue being captured within the ONR Issues tracking database. This will be monitored as part of routine regulatory business.

During the plant walkdown, we noted that the housekeeping arrangements met our standards and expectations. We further noted the high quality of recent upkeep work relating to the DPCS room, where the quality of housekeeping exceeded expected standards.

In summary, the SBI of the DPCS, inspected for Licence Conditions 10, 23, 24, 27 and 28, is rated as Green on the basis that relevant good practice was met and identified deficiencies in compliance arrangements were of minor nuclear significance.

Conclusion of Intervention

After considering the evidence examined during the sample inspection undertaken against Licence Conditions 10, 23, 24, 27 and 28, we consider that the DPCS met the requirements of the safety case.

There are no findings from this intervention that could significantly undermine nuclear safety at Heysham 2. At present, no additional regulatory action is needed over and above the planned interventions of Heysham 2 as set out in the Integrated Intervention Strategy.