Office for Nuclear Regulation

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Hinkley Point B planned Intervention

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake planned inspections at EDF Nuclear Generation Limited’s (NGL’s) Hinkley Point B power station in line with the planned inspection programme contained in the Hinkley Point B Integrated Intervention Strategy (IIS) for 2016/17. This was a joint inspection with the Environment Agency (EA).

Interventions Carried Out by ONR

We undertook a system based inspection of the solid and gaseous radwaste systems, during which we assessed compliance against the following licence conditions:

The nominated site inspector also undertook a number of engagements with the licensee representatives, which covered the following topics:

Explanation of Judgement if Safety System Not Judged to be Adequate

Based on the evidence sampled during this inspection, we judged that the solid and gaseous radwaste systems adequately meet the requirement of the safety case.

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

In relation to the system based inspection of the solid and gaseous radwaste systems, we made the following observations and judgements:

LC 10 - Training

We sampled the training materials and records for staff with direct responsibility for undertaking operations and maintenance activities on the system and found these to be suitable and sufficient. Based on the evidence sampled and interactions with station personnel, we judge that the requirements of LC10 have been met and thus, an IIS rating of Green is appropriate

LC 23 - Operating Rules

We identified limits and conditions in relation to the availability of the contaminated vent extract defined within the environmental specification (E1.2), and confirmed that these were reviewed on a daily basis where relevant.  The extant status of system availability stated in the daily operational focus meeting accurately reflected what was seen on the plant walk down.  We noted that there was some discrepancy between the temperature limits defined within the instructions for the irradiated fuel dismantling and desiccant vaults and the safety case documentation. Whilst we do not consider these discrepancies to have significant nuclear safety implications, a regulatory issue has been raised to monitor progress.   Based on the evidence sampled, we judge that the requirements of LC23 have been broadly met and an IIS rating of Green is appropriate.

LC 24 - Operating Instructions

We sampled the operating instruction associated with the change of contaminated filters and also discussed the filter changing operation with an operator. We judge that the requirements of LC24 have been broadly met and an IIS rating of Green is appropriate.

LC 27 - Safety Mechanisms, Devices & Circuits

As part of the plant walk down, we observed that the contaminated ventilation extract was available and in an acceptable condition.  We also sampled the maintenance activities of the interlocks associated with the irradiated fuel dismantling vault.  Based on the evidence sampled, we were satisfied that the contaminated ventilation extract and debris vault systems are being managed in such a way that the respective safety case claims are being met and that the systems are available and in a good working order. Accordingly, an IIS rating of green is considered appropriate.

LC 28 - Examination, Inspection, Maintenance and Testing

We sampled the maintenance records for the contaminated ventilation extract and two yearly inspection of the irradiated fuel dismantling vault.  Overall, we were satisfied from the activities sampled that examination, inspection, maintenance and testing is being undertaken in accordance with the maintenance schedule and to the right standard.  Accordingly, an IIS rating of green is considered appropriate.

LC 34 - leakage and escape of radioactive material and radioactive waste

We examined the actions from the recent LC34 assessment report which covered the solid and gaseous radioactive waste systems.  Priority 1 and 2 actions from the report were sampled and found to be adequately closed out.  Annual inspections to monitor for the presence of water had been completed. From the evidence sampled, we judged that compliance against LC34 was adequate and an IIS rating of green is appropriate.

Conclusion of Intervention

From the evidence gathered during the system based inspection of solid and gaseous radwaste systems, we allocated inspection ratings of ‘Green’ for LC 10, LC 23, LC 24, LC 27, LC 28 and LC 34.

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