Office for Nuclear Regulation

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System Based Inspection, SBI-01, Civil Engineering - Buildings, Site Infrastructure and PCPV

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at Heysham 2 power station in line with the planned inspection programme contained in the Heysham 2 Intervention plan. The intervention was undertaken by the Office for Nuclear Regulation (ONR) nominated site inspector and two civil engineering assessors.

Interventions carried out by ONR

This intervention involved undertaking a safety case system based inspection of the key civil engineering structures, mainly the Pre-stressed Concrete Pressure Vessel (PCPV), the Pressure Vessel Cooling System (PVCS) and the fire barriers throughout the Reactor Building. Through examination of this system we performed compliance inspections against LC 12: Duly authorised and other suitably qualified and experienced persons; LC 23: Operating rules; LC 24: Operating instructions; LC 27: Safety mechanisms, devices and circuits; and LC28: Examination, inspection, maintenance and testing. Our inspections were based on sampling the implementation of the arrangements in place against each licence condition. I held pre- and post- inspection meetings with Heysham 2 management where the inspection agenda was discussed and the outcome of the inspection was communicated.

LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) was not applicable to the chosen structures and therefore it was not considered during the inspection.

Explanation of judgement if safety system not judged to be adequate.

This system based inspection judged that the civil engineering structures and systems (PCPV, PVCS, fire barriers and Charged Hall Crane) meet the requirements of the safety case and is adequate.

Key findings, Inspector's opinions and reasons for judgements made

From an LC12 perspective, the overview of the safety case by those involved from Nuclear Generation Limited (NGL) demonstrated that they were Suitably Qualified and Experienced Personnel (SQEP) in the areas of the safety case as well as the operating rules and instructions in place for the PCPV and PVCS systems inspected. The inspection of staff training records and profiles found a minor shortfall associated with a training course that was required for one individual. Station had previously identified this and had put in place measures to enrol the individual for the next available course. Station also provided a justification to support the experience and knowledge of the individual in relation to the role being performed. I consider the LC12 element of this inspection to be adequate, warranting an associated Integrated Intervention Strategy (IIS) rating of 3.

From an LC23 perspective, based on the evidence sampled during this inspection, the implementation of the technical specifications, commentaries, and schedules has been demonstrated to be consistent with the claims and arguments presented within the safety case for PCPV and PVCS systems inspected. I consider the LC23 element of this inspection to be adequate, warranting an associated IIS rating of 3.

From an LC24 perspective, based on the evidence sampled during this inspection, I was content that the provisions in place as required by the PCPV and PVCS safety case were adequately implemented at Heysham 2. The operating rules under LC23 have been implemented through station and plant operating instructions, which was confirmed by sampling documents and records during the inspection. I consider the LC24 element of this inspection to be adequate, warranting an associated IIS rating of 3.

From an LC27 perspective, based on the evidence associated with the thermocouples, vibrating wire strain gauges (VSWG) and PVCS sampled during this inspection, I consider that the LC27 element of this inspection to be adequate, warranting an associated IIS rating of 3.

Examination, inspection, maintenance and testing under LC28 involved sampling a number of maintenance tasks including completed records and check sheets as well as consideration of material condition as part of the plant inspection. I consider the LC28 element of this inspection to be adequate, warranting an associated IIS rating of 3. However removal of the rock anchor from the Maintenance Schedule (MS) has been identified as a shortfall, however, this has been captured by Station within a Condition Report in accordance with their arrangements. I am content that this matter can be addressed as part of normal regulatory business, hence no formal action is required.

The licence conditions were inspected against ONR's published guidance requirements (as described in our technical inspection guides).

Conclusion of intervention

After considering all the evidence witnessed during each of the sample inspections undertaken against LCs 12, 23, 24, 27 and 28 I consider that the civil structures subject to this system based inspection meet the requirements of the safety case and its' implementation is deemed adequate.

A number of observations were made as a result of this system based inspection, however, given that they are of minor nuclear safety significance, I am content that they be addressed by NGL in accordance with their own arrangements. NGL has raised two Condition Reports (CR870308 and CR871551) that capture the observations as a number of actions.

There are no findings from this inspection that could significantly undermine nuclear safety.