Office for Nuclear Regulation

SBI19 – Heating and Ventilation

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at EDF Nuclear Generation Limited’s (NGL) Heysham 1 power station (HYA) power station in line with the inspection programme contained in the HYA Integrated Intervention Strategy (IIS) Plan for 2015/16. This compliance inspection and information exchange meetings was undertaken with NGL’s Independent Nuclear Assurance (INA). An ONR specialist mechanical engineering inspector supported the inspection providing regulatory input and challenge.

Interventions Carried Out by ONR

I undertook a safety case informed system-based inspection of the Heating and Ventilation (H&V) systems [SBI19] at HYA, with representatives of NGL’s INA. The inspection sampled compliance against several licence conditions, specifically LC10 (Training), LC23 (Operating Rules), LC24 (Operating Instructions), LC27 (Safety Mechanisms, Devices and Circuits), LC28 (Examination, Inspection, Maintenance and Testing - EIM&T) and LC34 (Leakage and Escape of Radioactive Material and Radioactive Waste).

Explanation of Judgement if Safety System Not Judged to be Adequate

Inspectors judged that the arrangements and their implementation, associated with H&V Systems, met the requirements of the safety case and are adequate.

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

In respect of LC10, training profiles and records of the system engineering were in-line with my expectations. On-going improvements and further specific training are being carried out. I therefore judge the LC10 element of this inspection to be adequate, warranting an associated IIS rating of 3 - Adequate.

In respect of LC23 I am satisfied that, based on the evidence sampled during this inspection, the implementation of relevant technical specifications, commentaries, and schedules were judged to be consistent with the claims presented within the HYA station safety case for the H&V and associated systems. An IIS rating of 3 – Adequate is therefore appropriate.

Based on the evidence sampled I am satisfied that operating instructions are of a good standard. Sampled documents clearly reflect the purpose and requirements of the safety case, provide clear guidance and instruction to operators on how to undertake the procedures covered. I therefore judge that an IIS rating of 2 – Good is appropriate for LC 24.

In respect of LC27, safety mechanisms, devices and circuits important to safety are well maintained and suitable surveillances are undertaken to ensure they are available. A single occurrence was identified on the central control room H&V system where a surveillance gap was identified; a condition report has been raised to address this gap. Suitable EIM&T activities are in place for the system, I therefore judge an IIS rating of 3 – Adequate remains appropriate.

For LC28, the licensee demonstrated adequate processes, procedures and records in place for safety mechanisms and the examination, inspection, maintenance and testing of plant which may affect safety. Several samples were taken and suitable records were produced for each sample. I judged the LC28 compliance element of this inspection to be adequate, warranting an associated IIS rating of 3 - Adequate.

In respect of LC34, the licensee demonstrated that arrangements required for containing and detecting leaks of radioactive materials and waste were not applicable with the heating and ventilation systems I sampled. I am therefore satisfied that for the purpose of this inspection, LC 34 is not applicable.

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

From the evidence sampled, witnessed and collected during the inspection against LCs 10, 23, 24, 27, and 28, I judge that, from a mechanical engineering perspective, overall the H&V system adequately fulfils the requirements of the safety case.  . I do not consider arrangements made under LC 34 to be applicable to the systems I sampled.

A number of minor observations were made as a result of this system-based inspection associated with the safety case operating rules, routine maintenance and long term asset management of the heating and ventilation systems sampled. These matters were raised by INA as opportunities for improvement and will be addressed as part of the licensee’s condition reporting and corrective action process.

Given that all observations made are of minor nuclear safety significance, I am content that they will be addressed by the licensee in accordance with their own corrective action programme arrangements. There are no findings from this inspection that could significantly undermine nuclear safety.