Office for Nuclear Regulation

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Inspection of post-implementation of the Essential Systems Outage Program (ESOP) Torness

Executive summary

Purpose of intervention

The purpose of the intervention was to undertake a post-implementation inspection of the essential systems outage program (ESOP) Torness risk monitor at Torness power station. This intervention also addresses my recommendation to undertake such an inspection, that resulted from my assessment of the licensee's case to implement ESOP Torness.

Interventions carried out by ONR

I carried out a joint inspection with EDF Energy Nuclear Generation Ltd's (NGL) internal regulator of ESOP Torness. I considered the adequacy of the arrangements for use of ESOP Torness against the requirements of Licence Condition 23 (Operating rules).

This intervention relates to ONR issues database issue number 1623.

Explanation of judgement if safety system not judged to be adequate

Not applicable as this intervention was not related to a safety system inspection.

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

Based on the overview of the use and experience of ESOP Torness provided by station, no significant areas of concern were identified, and indeed areas of good practice were highlighted.

I consider the Nuclear Safety Group's arrangements to review ESOP Torness assessments and provide advice for conflicts between deterministic and probabilistic assessments, single failures and no protection are adequate.

I have no cause for concern based on my review of a sample of ESOP Torness assessments for the first year of operation and discussion with station. There was good evidence of station being risk aware and actively trying to reduce the level of risk as low as reasonably practicable, which has increased since the implementation of ESOP Torness.

I consider the arrangements for managing ESOP Torness issues are adequate.

In terms of information security, access to the live database is controlled with the majority of users only having read access. Nuclear Safety Group approve the addition of extra users with write access. Based on the discussion, no issues relating to ESOP Torness security were identified.

The training relating to ESOP Torness provided prior to the implementation of ESOP Torness covered a sufficient range and number of station staff. Furthermore, I consider the ongoing training provision is adequate.

Station is making acceptable progress towards addressing all its post-implementation commitments.

I discussed the use of ESOP Torness with a representative from work planning and a representative from operations. Based on this discussion, it appears that ESOP Torness has been well received by station staff, staff are confident in the tool, it is actively being used to try to balance the risk profile and thereby reduce the level of risk as low as reasonably practicable, and it has raised awareness of the plant risk across the station. No issues with availability of ESOP Torness were identified.

Conclusion of intervention

Overall this was a positive intervention, with no areas of concern identified. The following positive aspects were identified:

I provided advice in a number of areas, although none of this was significant, which station will consider under normal business. I will continue to monitor NGL's progress in resolving the regulatory issue that captures the post-implementation commitments under normal regulatory business. Based on this intervention, no regulatory action is required.