Office for Nuclear Regulation

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Sellafield - LC35 inspection in Decommissioning Division

Executive summary

Purpose of intervention

This intervention was to inspect the arrangements for compliance with Licence Condition 35 (Decommissioning) within Sellafield Ltd's Decommissioning Division.

Inspection of Licence Condition (LC) compliance at nuclear licensed sites is an important part of ONR's activities. ONR's Sellafield Programme has defined a programme of system inspections and LC compliance inspections which focus on those plants and activities where the risk or hazards are most significant. This LC compliance inspection forms part of that programme and is identified on the Sellafield PP3 Inspection plan which covers the Decommissioning Division.

Interventions Carried Out by ONR

I carried out an inspection of the arrangements for Decommissioning in the Sellafield Decommissioning Division through office based examination of procedures, documents and interviews with staff. Licence Condition 35 (LC35) requires the licensee to make and implement adequate arrangements for the decommissioning of any plant or process which may affect safety, and to make arrangements for the production and implementation of decommissioning programmes for each plant. This inspection was carried out in accordance with ONR's inspection guidance for LC35 as defined in NS-INSP-GD-035. In addition I reviewed the development of Sellafield Ltd arrangements and strategies to determine how these align with the expectations defined in ONR's guidance.

Explanation of Judgement if Safety System Not Judged to be Adequate

N/A - This was not a Safety Systems inspection.

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

I was satisfied that those aspects of Sellafield Ltd (SL) decommissioning arrangements sampled during this inspection meet the requirements of Licence Condition 35.

I reviewed the SL Decommissioning Strategy and Decommissioning Integrated Strategic Plan (DISP). These plans have been developed with visibility and input from ONR, the Environment Agency (EA) and the Nuclear Decommissioning Authority (NDA) and align to the high level strategies agreed with these key stakeholders. SL adequately demonstrated how these key documents connect together and both underpin the approach used to prioritise the decommissioning programmes for the site, and support SL's Performance Plan (PP14).

I reviewed the arrangements and governance for Key Decommissioning Milestones (KDMs), and saw how these are managed for each work stream. I considered the governance of these to be adequate. It was encouraging to see that SL has now aligned the KDMs to the Cardinal Milestones agreed with NDA to form a single common set of decommissioning milestones aligned with the expectations of all key stakeholders.

SL is applying significant effort to the development of Post Operations Clean Out (POCO) procedures to ensure that, following operations, plants are handed over for decommissioning in a clearly defined and suitable condition for further decommissioning. Whilst these are still evolving as more experience is gained across site, I consider the development of these arrangements to be a positive step which should prevent current operational plants on the site from encountering the same difficulties in decommissioning as some of the legacy plants.

SL stated an expectation that there will normally be a 30 year deferral period following POCO for many plants, but could not articulate the basis for this being a reasonable planning assumption. I challenged how this fits with the policy that decommissioning should be carried out as soon as reasonably practicable (taking relevant factors into account), and where deferral is proposed that this should be rigorously justified. SL confirmed they comply with this policy, and 30 years is only used as a basis assumption and a starting point for more detailed planning.

I discussed the arrangements for the provision of safety cases to justify safety during decommissioning, and SL confirmed that these arrangements are being improved to be more suitable for decommissioning. The revised arrangements will clarify the safety case expectations and approaches to be used throughout POCO and onto the completion of decommissioning. One proposal SL is considering is that the POCO safety case is based on the operational safety case (with modifications), and that a separate decommissioning safety case will take over once POCO is complete. I considered this a reasonable proposal.

I identified a potential gap in SL's arrangements for the provision of suitable decommissioning programmes for each plant. SL stated that documentation exists for each facility which it believes is adequate for the stage in its lifecycle, but that this may not necessarily align to the terminology or format prescribed in ONR's Technical Inspection Guide. SL agreed to review ONR's suite of guidance for decommissioning, to identify the significance of this potential gap and propose a plan to address any shortfalls.

Conclusion of Intervention

Overall, I judged compliance with Licence Condition 35 to be adequate, as arrangements were demonstrated to be in place for the decommissioning of plants or processes which may affect safety. Although some aspects of the arrangements are still being developed to deliver improvements which support the Sellafield plan, I judged the overall arrangements to adequately meet the requirements of LC35. Three minor actions were identified which are detailed in the report. The development of the arrangements and follow up of agreed actions will form part of routine regulatory business.