Date(s) of inspection:
- November 2022
Aim of inspection
Sellafield Ltd has requested ONR agreement to commence the Pile Fuel Storage Pond (PFSP) Diving Pilot. This involves the introduction of a specialist team of diving contractors, Underwater Construction Corporation (UCC), into PFSP bays 11 and 12.
Sellafield Ltd has already undertaken significant clearance of bays 11 and 12 of PFSP using a range of techniques including remotely operated vehicles and operators using long reach tooling stood at the bay edge and have now reached a point where alternative methods are required to remove the remaining fixed items, clear debris and sludge from difficult areas of the floor to allow the project to proceed.
Sellafield Ltd has identified an option of deploying divers in the pond. Recognising the novel nature of this work, Sellafield Ltd requested permission to trial the deployment of divers in Bays 11 and 12 only.
The purpose of the inspection was to inspect Sellafield Ltd’s implementation of the Plant Modification Proposal (PMP) for the PFSP diving pilot in bays 11 and 12 which has been made under Licence Condition (LC) 22 arrangements. In particular, to gain confidence that the safety case is understood by the licensee and that the people, plant and processes will be in place prior to deployment of the divers. The findings of the inspection will be used to inform the decision in response to Sellafield Ltd’s request for ONR agreement to commence the PFSP diving pilot in bays 11 and 12 (ONR-SDFW-PAR-22-002). This intervention is in accordance with ONR’s strategy to ensure delivery of activities and key enablers to support safe and secure risk and hazard reduction in the Sellafield legacy ponds.
Subject(s) of inspection
- LC 22 - Modification or experiment on existing plant - Rating - Green
Key findings, inspector's opinions and reasons for judgement made
Based on the evidence sampled during this intervention several outstanding issues were identified in the following areas which need to be rectified prior to commencement of the diving:
- Safety Case Documentation - several documents are still in draft status or currently being developed.
- Training and briefings of key personnel (PFSP Duly Authorised Persons (DAPs) and Safe Systems Controllers (SSCs), Health Physics and Surveillance (HP&S) and UCC dive team) is ongoing therefore incomplete.
- Facility readiness: shielded dive stands were not available on plant, and substantiation of their safety function had not been completed.
- Sellafield Limited readiness governance process has yet to be completed.
- Several actions remain outstanding from the internal oversight function (Nuclear Intelligence and Internal Oversight (NI&IO)) review.
Although there were several aspects requiring completion, Sellafield Ltd. demonstrated that that these were being adequately controlled and managed through the Plant Modification Proposal (PMP) and the project implementation plan.
There was a clear 'golden thread' from the safety case through to substantiation of safety measures and their inclusion on the engineering schedule and operational clearance certificate / operating instructions. The requirements for commissioning engineered safety measures were appropriately captured in the commissioning test definition document with evidence of completion of the tests documented in commissioning worksheets.
From the evidence sampled we identified a number of areas where Sellafield Ltd. demonstrated good practice; at the same time we provided some observations regarding some areas for minor improvement. I gained confidence in Sellafield Ltd.’s ability to safely implement the proposal to commence the diving pilot in PFSP Bays 11 and 12 in the near future. Commencement is dependent on ONR Agreement.
I consider, noting the ONR guidance on inspection ratings, that the inspection merited an inspection rating of Green (no formal action) for implementation of its LC 22 arrangements.
I will use the findings of the inspection to inform ONR’s assessment of Sellafield Ltd.’s request for Agreement to commence the diving pilot in PFSP Bays 11 and 12.
Conclusion
UCC are a notified contractor and member of the Association of Diving Contractors with considerable experience in nuclear diving in the UK and overseas and are familiar with the UK’s Diving at Work Regulations 1997 and relevant statutory provisions.
The project documentation, diving project plan, method statements, risks assessments and emergency arrangements appear to be suitable and sufficient. There is a process for reviewing and revising these documents as necessary. A suitable permit to work system and management of change procedure is in place to address any requirements for deviation from the agreed methodology or systems of work.
A review of the competencies of the diving team suggests that those taking apart have the required qualifications, knowledge, skills and experience. With the exception of a few outstanding medical certificates of fitness to dive there are no concerns with the competencies of the diving team. There appears to be sufficient people with suitable competence to conduct the diving operation safely.
The diving plant appears suitable and sufficient. Uniquely to this project much of the plant is new and will be replaced due to contamination controls well before its required servicing date. In addition, due to the short duration of the pilot project, many items will not require servicing or recertification before the end of the project. Of the plant that will require serving there appears to be in place a suitable planned maintenance system.
The client for the project, SL, have in place a competent diving technical authority to advise them on diving matters. The diving technical authority will be involved with monitoring and reviewing the project as it proceeds.
HSE specialists stated that they are content that there are no significant reasons why the diving project so should not proceed as planned, notwithstanding the few, simple actions listed below which should be addressed. From a perspective of the diving operations HSE are content for SL to be granted a licence instrument by ONR for the pilot project.
From the evidence sampled we identified a number of areas where Sellafield Ltd. demonstrated good practice; at the same time we provided some observations regarding some areas for minor improvement. I gained confidence in Sellafield Ltd.’s ability to safely implement the proposal to commence the diving pilot in PFSP Bays 11 and 12 in the near future. Commencement is dependent ONR Agreement.
It was not possible to gather sufficient evidence during the inspection close RI-11123.
I consider, noting the ONR guidance on inspection ratings, that the inspection merited an inspection rating of Green (no formal action) for implementation of its LC22 arrangements.
I will use the findings of the inspection to inform ONR’s assessment of Sellafield Ltd.’s request for Agreement to commence the diving pilot in PFSP Bays 11 and 12.