Office for Nuclear Regulation

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Inspection of Radio Frequency Interference Testing of the TA7 Governor Room Control Panels

Executive summary

Purpose of intervention

The absence of an electromagnetic interference (EMI)/radio frequency interference (RFI) hazard safety case for all seven advanced gas-cooled reactor (AGR) power stations is a shortfall against modern standards. To address this shortfall an AGR generic EMI/RFI hazard safety case is being developed by the licensee (EDF Nuclear Generation Limited (NGL)) to encompass all relevant power stations.

Hinkley Point B (HPB) power station is designated as the lead station in the EMI/RFI hazard safety case paper of principle (Ref. 6.1). This intervention examines the first phase of RFI testing being undertaken at HPB, which will be used as a template for the rest of the AGR stations.

The process for the qualification of equipment is outlined in the paper of principle (Ref. 6.1). Step 14 of Phase 5 of Ref. 6.1 requires that equipment without satisfactory qualification evidence to the functional safety levels specified in the EMI/RFI equipment qualification testing requirements (Ref. 6.2), should undergo RFI testing to enable NGL to complete its evaluation and determine fitness for purpose in the context of EMI/RFI hazards.

Interventions carried out by ONR

This intervention forms a part of a series of Level 4 meetings and inspections as defined in intervention project record NGL-052 (Ref. 6.5) to assess progress being made by NGL in the production of a generic AGR stations EMI/RFI hazard safety case.

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

I am content that the RFI susceptibility test procedure provides adequate test coverage to assess the extent of the hazard posed to existing equipment without satisfactory qualification.

This is the first stage of RFI testing to support implementation of the generic EMI/RFI hazard safety case and, as such, NGL have agreed to formally document the risk assessment process, the scope of RFI testing and the decision process adopted when sanctioning RFI testing results.

Conclusion of intervention

I am satisfied that the RFI susceptibility test procedure provides adequate test coverage to assess the extent of the hazard posed to existing equipment without satisfactory qualification.

Further development of NGL's testing methodology, risk assessment process, scope of RFI testing and sanctioning of RFI testing results will be examined during routine Level 4 meetings and inspections to ensure the generic AGR stations EMI/RFI hazard safety case is fit for purpose.

Recommendations

No recommendation arose from this inspection.