Office for Nuclear Regulation

Heysham 1 System Based Inspection of the  Data Processing and Control System

Executive summary

Purpose of Intervention

This was a planned inspection of EDF Energy Nuclear Generation Ltd’s (EDF NGL’s) Heysham 1 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 1 Integrated Intervention Strategy (IIS).

Interventions Carried Out by ONR

This intervention covered both safety and security. 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 security aspect of this intervention was conducted under the requirements of the Nuclear Industries Security Regulations (NISR) 2003 and considered if the requirements of the Security Case and Security Operating Procedures had been met, in particular to confirm the application of physical, administrative, procedural and technical security controls specific to the Data Processing and Control System.

The inspection was undertaken by two control and instrumentation (C&I) specialist inspectors, two human factors specialist inspectors and a specialist security inspector from the ONR Civil Nuclear Security and Safeguards division, Cyber Security and Information Assurance sub-division. 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 and NISR 2013. 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 and security case requirements.

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 the Safety System, including its security, Not Judged to be Adequate

From this inspection, we judged that overall the safety and security provisions applicable to the DPCS met the requirements of the safety and security cases respectively.

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

During the course of this SBI, it was found that Heysham 1 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.

When reviewing Technical Specification (Tech Spec) 3.1, we found that generally limits and conditions were clearly defined, however, we noted that the references to specific DPCS formats and / or group 2 alarms were absent from two sections of Table 3.1-3. In addition, we noted that an associated Station Operating Instruction lacked the level of detail that was evident in the ‘tech spec’. We placed and action on EDF NGL to review both the Tech Spec and the Station Operating Instructions in this regard.

We identified a shortfall in compliance with two of EDF NGL’s internal specifications regarding a) the periodicity of plant walkdowns, where we considered that the frequency of the walkdown was not sufficient. And b) the  ‘as found condition’ of equipment and / or components was not accurately recorded during maintenance. We requested that EDF NGL inform ONR why they were non-compliant and provide a plan to ensure they became and maintained compliance.

In addition, we identified that the Safety System Reviews were not identified on the maintenance schedule and were not undertaken at any specific interval, the last one on Reactor 2 being June 2018. ONR requested that EDF NGL provide and explanation as to why the Safety System Review is not on the maintenance schedule or undertaken on a scheduled basis, providing appropriate justification, or alternatively add this review to the maintenance schedule.

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, including significant improvements concerning security.

In summary, the SBI of the DPCS, inspected for Licence Conditions 10, 23, 24, 27 and 28, and, in addition, NISR 2013, 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, and NISR 2013, we consider that the DPCS met the requirements of the safety case and security case respectively.

There are no findings from this intervention that could significantly undermine nuclear safety or security at Heysham 1. At present, no additional regulatory action is needed over and above the planned interventions of Heysham 1 as set out in the Integrated Intervention Strategy.