Office for Nuclear Regulation

Licence Condition Compliance Inspections covering LC7, 21, 22

Executive summary

Purpose of intervention

The purpose of this intervention was to conduct Licence Condition (LC) compliance inspections at EDF Energy Nuclear Generation Limited’s Torness Power Station in accordance with the planned inspection programme contained in the Torness Integrated Intervention Strategy (IIS) for 2015/16.

This intervention was undertaken by two ONR inspectors, namely the outgoing and incoming Nominated Site Inspector, respectively, for Torness Power Station.

Interventions Carried Out by ONR

This intervention included compliance inspections against the following Licence Conditions (LCs):

The inspection undertaken utilised ONR guidance documents, NS-INSP-GD-007 Revision 2, NS-INSP-GD-021 Revision 3 and NS-INSP-GD-022 Revision 3, which require inspectors undertaking compliance inspections against LC7, LC21 and LC22 to consider both the arrangements that are in place together with their associated implementation.

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system inspection was undertaken, hence this is not applicable.

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

The LC7 inspection focussed on the arrangements for condition reporting of equipment shortfalls and the occurrence of adverse events on the site. This included a review of the approaches applied to their prioritisation and assignment for action, recording and trending to ensure that operational experience underpins continuous improvement activities. We also attended a Daily Screening Meeting to assess the process followed in the prioritisation and allocation of a range of condition reports to departments/groups for further investigation and, as necessary, corrective action.

We found that the arrangements for compliance with LC7 covered during this inspection provide an adequate demonstration of the approach taken to satisfy relevant expectations of ONR guidance. This sample inspection considered both the arrangements and their implementation including the processes applied to trending of condition reports.

The LC21 inspection was made against the licensee’s arrangements in terms of the management and control of commissioning activities that are applicable to safety-related plant and systems by suitably qualified and experienced personnel. This considered a sample of the activities associated with an ongoing project to enhance an electrical protection system at Torness in order to demonstrate the effectiveness of the commissioning arrangements, including project governance and the implementation of a commissioning test schedule and quality planning processes.

This inspection included a walkdown of the modifications implemented at an electrical cubicle in an Essential Supplies Building to implement a logic voting configuration to enhance the resilience of the protection system. This is considered to be a significant safety improvement in the capability of this system to withstand single failures that have previously resulted in spurious shutdown of a reactor at Torness.

Based on the sampling undertaken, we found that the implementation of the LC21 arrangements for the commissioning of safety-related systems to be effective.  The protection system enhancement project station has fully implemented the arrangements described in both station and corporate level specifications and procedures with the exception of fully updating all affected documents. A condition report was raised by station to address this minor shortfall and review the document backlog to ensure that all safety-related documentation is updated to reflect the modified configuration of the protection system.

The LC22 inspection focussed on the implementation of arrangements at Torness Power Station for modifications that are scheduled to be implemented as part of the forthcoming Reactor 2 2015 outage. This enabled a review to be carried out on a series of modifications in terms of their safety significance, the implications this may have on the provision of documentation to justify the safety of a proposed modification and its implementation during the outage and their current status.

Our inspection found that, with one exception all outage-related modifications had reached an approved stage status. It was established that work is now focussed on ensuring that other aspects of the modifications such as development of work instructions, completed drawings, operating and maintenance instructions are completed in a timely manner in advance of their implementation. During this inspection we also sampled the scope change process that enables additional work to be added to the outage programme only when the design is complete and funding is available for the modification to be implemented.

This inspection went on to consider the process of developing Engineering Changes (ECs) in response to incidents on site by reviewing the response to a recent event. The response involved use of a safety case anomalies process that resulted in the development of a nuclear safety requirements specification for a category 2 EC that is intended to be implemented during the forthcoming Reactor 2 outage. A nuclear safety requirements specification was determined to be necessary in this instance to outline the safety case approach and set out its claims and arguments. We found that there was a clear auditable trail from initial identification of a safety case anomaly through to the nuclear safety requirements specification and production of a suitably categorised EC that demonstrates how station implements its arrangements under LC22.

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

We are satisfied that the arrangements and their implementation at Torness for LC7, LC21 and LC22, respectively, are adequate and judge that the outcome of the sample inspections undertaken met expectations detailed within relevant ONR guidance.  I have therefore rated the respective LC7, LC21 and LC22 elements with an IIS rating of 3, adequate.

There are no findings from this inspection that could significantly undermine nuclear safety or which would result in changes to the planned interventions and inspections of Torness Power Station.