Office for Nuclear Regulation

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Compliance Inspections at Hunterston A

Executive summary

Purpose of intervention

This report covers interventions carried out as part of ONR's regulation of operations undertaken at the Magnox Hunterston A (HNA) site.

Interventions Carried Out by ONR

Four planned Compliance Inspections were undertaken relating to Licence Condition (LC) 7 (Incidents on site), LC11 (Emergency arrangements), LC21 (Commissioning) and LC36 (Organisational capability) together with an Action/Issue review and a meeting with site Safety Representatives.

The licence conditions were inspected against ONR's published guidance requirements, as described in our technical inspection guides, which can be found at Office for Nuclear Regulation (ONR) Compliance inspection - Technical inspection guides. Further information on Integrated Intervention Strategy (IIS) ratings, is available at

Explanation of Judgement if Safety System Not Judged to be Adequate


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

HNA provided an overview of their Arrangements and recent performance against LC7 including their Improvement Plan put in place to address a Regulatory Issue identified from a previous intervention by ONR. Suitable progress has been made against Regulatory Issue 4401 to enable its closure. HNA informed ONR that the Apparent Cause Investigation route will be removed to improve identification of root causes.

HNA are moving from Emergency Response Arrangements governed by REPPIR to local Contingency Arrangements underpinned by a re-assessment of consequences following an Event. Two successful demonstration exercises were carried out and witnessed by ONR that demonstrated these Arrangements to be adequate.

The Compliance Inspection against LC21 identified that improvements are required to the execution and recording of commissioning tests and the handling of Design Changes resulting from commissioning activities. Active commissioning progression is contingent upon HNA satisfying ONR that Arrangements and their implementation are adequate.

Clarification is required regarding the Nuclear Baseline responsibilities assigned to Programmes and Sites within the revised Magnox operating model with reference to ONR guidance on licensee core and intelligent customer capabilities; NS-TAST-GD-049.

A planned intervention relating to action tracking and Issue management was undertaken as was a meeting with the Site Safety Representatives.

Conclusion of Intervention

I consider that No Formal Action (GREEN) is the appropriate rating for HNA compliance against LC7, LC11 and LC36.

I consider that Issue 4401 can now be closed.

ONR findings related to LC21 require that ONR demand improvement (RED). ONR will use the Enforcement Management Model to inform their response to HNA regarding these findings and appropriate Regulatory Issue(s) will accordingly be raised.