Office for Nuclear Regulation

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Magnox Limited (MXL) - Winfrith - Planned Intervention

Executive summary

Purpose of intervention

This was a planned inspection at Magnox Limited’s (MXL’s) Winfrith site, undertaken as part of the planned intervention strategy for the Winfrith site for 2015/16.

Interventions Carried Out by ONR

A MXL compliance assessor, the outgoing and incoming ONR nuclear safety site inspectors for Winfrith and the ONR Civil Nuclear Security (CNS) site inspector for Winfrith undertook a “Work Control / Control and Supervision / Licence Condition 26 (LC26)” inspection.  The objectives of this inspection were to:

  1. Inspect MXL Harwell & Winfrith LC26 compliance arrangements.
  2. Review the status of an ONR issue relating to work control.
  3. Discuss the follow up of a control and supervision related incident.
  4. Inspect the implementation of LC26 compliance arrangements at both a licensee facility [the Steam Generating Heavy Water Reactor (SGHWR)] and a tenant facility [Tradebe Inutec (TI)].
  5. Undertake a joint ONR nuclear safety and ONR security inspection.
  6. Undertake a joint inspection with the licensee internal regulator.

The joint inspection with the licensee internal regulator formed part of the ONR Integrated Intervention Strategy (IIS) plan for Winfrith.

We undertook planned information gathering.  This consisted of a series of tours and discussions as part of the handover between the outgoing and incoming ONR nuclear safety site inspectors for Winfrith.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

In relation to LC26 arrangements, we noted improvements to Harwell and Winfrith arrangements for work done by MXL personnel or by contractors under the Control & Supervision (C&S) of MXL personnel.  We concluded that these arrangements were adequate and that adequate progress was being made relating to an ONR issue relating to work control.  We noted that LC26 arrangements do not link to any MXL C&S arrangements for operations by tenants on the Harwell or Winfrith nuclear licensed sites and raised an issue for MXL to consider how such a link could be made.

In relation to implementation of LC26 arrangements at SGHWR, some issues were identified relating to demonstrating competency of persons with C&S roles for a selected task.  These issues were resolved following the inspection.  An issue was raised for MXL to propose a way forward to ensure that permissioning of the most safety significant operations on Category 1 (the most safety significant) facilities at Harwell and Winfrith is by Duly Authorised Persons.

In relation to implementation of LC26 arrangements at TI, we considered that the relevant Tenant Safety Requirements (TSRs) placed on TI by MXL were adequate.  We also considered that the TI C&S arrangements put in place to meet these TSRs were adequate.  Finally, we considered implementation of TI C&S arrangements to be adequate for a selected task.

We noted a key insight from a work control independent assessment by the licensee internal regulator that the work control process is embedded across the organisation.

Taking all these factors into account we (outgoing and incoming ONR nuclear safety site inspectors for Winfrith) assigned an Integrated Intervention Strategy (IIS) rating of 3 (adequate) to LC26.

The joint inspection with the licensee internal regulator was considered to be effective.

In relation to the other activities undertaken in this intervention, no key findings arose.

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

From the evidence gathered during this intervention, no matters have been identified that are likely to have a significant impact on nuclear safety on the site at this time.  Therefore, no additional regulator action arising from this visit is considered necessary at this time.