Office for Nuclear Regulation

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Torness - System Based Inspection - SBI 18 - Instrument Air and Turbine Overspeed Protection System

Executive summary

Purpose of intervention

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

The replacement of the tritiated effluent line was identified as an area of common interest to SEPA and ONR, and was therefore used as the basis for sampling during the course of this joint intervention.  

The joint inspection team was composed of SEPA’s nominated site inspector for Torness, ONR’s nominated site inspectors for Torness and Heysham 2, and an ONR inspector from the emergency preparedness and response programme.

Interventions Carried Out by ONR

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

We also held a routine update meeting with the licensee’s internal regulator.

Explanation of Judgement if Safety System Not Judged to be Adequate

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

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

Our LC14 inspection examined Torness’ arrangements for producing good quality, fit for purpose safety documentation, and sampled the station’s categorisation process to ensure that robust safety case review processes are applied to high hazard systems. We also examined Torness’ processes for ensuring that identified reviewers are suitably qualified and experienced, and are also independent of the safety case development process.

We tested the implementation of those arrangements on a significant recent project, and based on our inspection sample, we judge that Torness’ arrangements and the implementation of those arrangements meet the requirements of ONR LC14 inspection guidance. We have therefore given this inspection an IIS rating of 3 (adequate).

The plant walkdown and inspections against licence conditions 22, 26 and 28 were carried out jointly with SEPA’s nominated site inspector for Torness and with INA’s Regulatory Lead for Torness (plant walk down only). We examined Torness’ licence condition arrangements, and the implementation of those arrangements to the tritiated effluent line replacement project. We walked the full length of the tritiated effluent line, and examined the tented area where the construction and replacement of the effluent line will take place.

Given the collaboration of a number of different specialist companies and contract organisations, we challenged and tested Torness’ arrangements for maintaining adequate control and supervision for the duration of the replacement of the tritiated effluent line. We examined in particular Torness’ arrangements for quality control, for the isolation of lines whilst work is being undertaken, and for ensuring that troubleshooting experience gained by Torness’ Environmental Safety Group is effectively communicated to the project team for incorporation in the commissioning plans.

We examined a number of maintenance records related to items of equipment of environmental or nuclear safety significance selected during the plant walkdown, and we were satisfied that adequate examination, inspection, maintenance and testing is being carried out by Torness. We also noted that personnel interviewed were knowledgeable and familiar with the station’s arrangements.

ONR and SEPA jointly re-emphasised the environmental, nuclear safety and reputational importance of ensuring the successful replacement of the tritiated effluent line, with adequate quality control and isolation procedures in place for the construction of the new line.

Based on the areas sampled during the course of this joint ONR / SEPA inspection, we judge that Torness’ arrangements and the implementation of those arrangements meet the requirements of ONR LC22, 26 and 28 inspection guidance. We have therefore assigned IIS ratings of 3 (adequate) against the LC22, 26 and 28 elements of this inspection.

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 LC14, 22, 26 and 28 are adequate, and we judge that the outcome of the sample inspections undertaken meet expectations detailed within relevant ONR inspection guidance. We have therefore assigned a rating of 3 (adequate) for LC14, LC22, 26 and 28.