Office for Nuclear Regulation

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Revised building crane Safety Case and East End crane permissioning readiness review

Executive summary

Purpose of Intervention

The MSSS is a legacy facility on the Sellafield site that was built in the 1960’s to store Intermediate Level Waste under water and is currently assessed as the highest risk nuclear facility in the Nuclear Decommissioning Authority estates. In order to reduce this risk, Sellafield Ltd. has commenced a programme of work to retrieve the waste and store it in more modern/acceptable containment. Lifting operations within the Magnox Swarf Storage Silo plant are required to enable waste retrieval operations.

Currently the Magnox Swarf Storage Silo has one operational electric overhead travelling crane that does not have the required capacity to meet the demands of the retrievals schedule. Sellafield Ltd. recently installed an additional crane and has raised a modification to implement a revised crane case for the operation of the existing west end crane and new east end crane. The licensee requires ONR’s permission to implement this modification and bring the new east end crane into service.

The purpose of the intervention, which was undertaken on 21 and 22 August 2018, was to inspect Sellafield Ltd.’s readiness to implement its revised building crane safety case and bring the new crane into operation along with the existing crane. The findings of this intervention will be used to inform ONR’s regulatory decision to permission the activities.

Interventions Carried Out by ONR

Licence Condition (LC) 22: ‘Modification or experiment on existing plant’ requires the licensee to make and implement adequate arrangements to control any modification or experiment carried out on any part of the existing plant or processes which may affect safety.¬† ONR’s Technical Inspection Guide (TIG) for LC 22 contains guidance on assessing the adequacy of the arrangements and their implementation.

This inspection focussed on Sellafield Ltd’s implementation of its LC 22 arrangements and safety case relating to the aforementioned modification. The objective was to confirm that the activities associated with the modification have been successfully completed in accordance with the safety case and relevant arrangements, or adequate progress has been made to give regulatory confidence for ONR to subsequently permission implementation of the revised crane safety case for the operation of the existing west end crane and new east end crane in Magnox Swarf Storage Silo.

During this readiness review, I was supported by the ONR Mechanical Engineering and Human Factors specialists, and accompanied by the licensee’s Nuclear Independent Oversight function. ¬†This inspection comprised discussion with licensee staff and examination of documentation and records. No plant inspection took place on this occasion as the inspectors were sufficiently informed about this modification from previous interventions into the Magnox Swarf Storage Silo.

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system was inspected during this intervention.

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

Sellafield Ltd. confirmed that commissioning of the new east end crane has commenced but is currently paused due to the need to schedule time within the MSSS plant to install power onto the new crane to complete this commissioning. Consequently the licensee has not yet been able to prove some safety systems on the new east end crane. This is a pre-requisite before ONR considers issue of any permission.

Resulting from this readiness inspection, Sellafield Ltd. has identified outstanding matters that it needs to complete in order to demonstrate it is sufficiently advanced for ONR to permission implementation of the revised building crane safety case.

Sellafield Ltd. is aware of the remaining work required and I have raised a Regulatory Issue containing eight actions that require Sellafield Ltd to provide evidence that the east end crane has been successfully commissioned, maintenance instructions have been finalised and to provide additional information concerning operating arrangements. Sellafield Ltd is aware that it needs to complete these actions before ONR considers permissioning SL’s implementation of its revised crane case for the operation of the existing west end crane and new east end crane.

ONR requested the licensee to supply a schedule of activities to resolve these actions and the Sellafield Ltd’s Nuclear Independent Oversight function has been tasked with witnessing commissioning and confirming to ONR that the east end crane powered commissioning has been correctly been carried out and documented. ONR will sample safety mechanism commissioning and will review the finalised commissioning reports. I will continue to engage with Sellafield Ltd. to monitor completion of these actions. Consequently I do not consider that any further readiness review is required.

Conclusion of Intervention

LC22 requires that the licensee shall make and implement adequate arrangements to control any modification or experiment carried out on any part of the existing plant or processes which may affect safety.

My intervention confirmed that Sellafield Ltd. had made progress towards readiness for ONR’s permission for this modification, however as the east end crane commissioning has not been completed, Sellafield Ltd. is not ready to fully implement the modification at this time. Therefore ONR is unable to issue of any permission to Sellafield Ltd. For the implementation of its revised crane case for the operation of the existing west end crane and new east end crane. Consequently I have raised a new regulatory issue that contains eight actions were that have been accepted by Sellafield Ltd. Despite this finding, I was content that Sellafield Ltd. had followed its arrangements for LC22 and therefore I rate this inspection as green.