Sellafield - Inspection ID: 53428 | Office for Nuclear Regulation

Executive summary

Date(s) of inspection: June 2024

Aim of inspection

To purpose of this inspection is to gain assurance that Analytical Services is ready to implement its safety case for the remediation of Lab 54/54A. This readiness inspection is part of the permission strategy (PR-01171) in response to Sellafield Limited's request for ONR's agreement to this activity.

Subject(s) of inspection

LC10 - Training - Rating: Green
LC12 - Duly authorised and other suitably qualified and experienced persons - Rating: Green
LC23 - Operating rules - Rating: Green
LC24 - Operating instructions - Rating: Green
LC28 - Examination, inspection, maintenance and testing - Rating: Green

Key findings, inspector's opinions and reasons for judgement made

Sellafield Ltd has applied to the Office for Nuclear Regulation (ONR) for agreement to remediate Lab 54/54A within the B229 Analytical Services facility. This inspection was undertaken to inform ONR’s decision on this agreement.

The inspection team undertook the intervention which comprised inspecting against five relevant licence conditions (LCs) (LC10 - Training, LC12 - Duly authorised and other suitably qualified and experienced persons, LC23 - Operating rules, LC24 - Operating instructions and LC28 - Examination, inspection, maintenance and testing). The inspection comprised of a plant walkdown, discussions with key personnel and the sampling of documentation related to this modification.

The inspection team found, from the evidence sampled, that Sellafield Ltd is in an advanced state of readiness. Engineered and operational safety measures identified in the safety case for the proposed activity have been incorporated into operational documentation, including task based risk assessments and operator instructions. Engineered safety systems and associated maintenance records were available. Operators were SQEP for the tasks and additional training against safety case requirements was evidenced. Radiological protection arrangements had been adequately incorporated into operational documentation, including local rules, pre-job brief documentation and operator instructions.

The inspection team considered that the Sellafield Ltd Nuclear Independent Oversight (NIO) function had undertaken a comprehensive Assessment of People, Plant and Procedures (APPP) process and that, from discussions, Sellafield Ltd provided assurance that there was a plan to close all significant findings.

Based upon the evidence gained during this targeted inspection, in support of ONR's permissioning of the activity to remediate Lab 54/54A, I judge that Sellafield Ltd has demonstrated its readiness to commence this activity. Sellafield Ltd has committed to closing out its own internal review actions, and the observations made by ONR during the inspection.

Conclusion

The purpose of this readiness inspection was to provide assurance that Sellafield Ltd have put in place the people, plant and procedures to safety commence the remediation of Lab 54/54A. In this regard, the inspection team made the following findings:

People - LC10 (Training) & LC 12 (Duly authorised and other suitably qualified and experienced persons)

Operator training is provided through a number of corporate training packages, both classroom and practical. A training matrix spreadsheet and minimum operational manning level document sampled demonstrated that more operators were trained for the task than were required. It was also noted that the team of operators had undertaken similar tasks on other labs.
Additional operator training has been delivered through a safety case training booklet to train operators against the safety case measures specific to this project. The contents of this training booklet will be reinforced during a training away day.
Sellafield Ltd provided evidence that it had carried out an emergency drill to test contingency arrangements to support operator training, which is considered good practice.

Plant - LC28 (Examination, inspection, maintenance and testing)

The most recent differential pressure testing results for the HEPA filters on both the B229 main ventilation system and the local 50 series ventilation systems were sampled. All results were within specified limits and showed no negative trend. The mechanical engineering inspector was content that this modification does not need to be complete prior to commencement of Lab 54/54A decommissioning activities.
The maintenance history for the extract fans for both ventilation systems were sampled. All maintenance was found to be in date and complete.
The main extract fans for the B229 main ventilation system are subject to a 4 weekly condition monitoring inspection by an external provider. The most recent of these was sampled and no points of concern were noted. The use of condition monitoring provides confidence that the main ventilation system can continue to provide its claimed functions despite its age.
Progress towards the closure of engineering shortfalls identified within the safety case submission was reviewed. All identified actions were confirmed to have been closed with the exception of the C5 containment leakage across the emergency access door. Through discussions, the inspection team were confident Sellafield Ltd had in place a plan to rectify this issue prior to the start of work. An action had been raised on the ALTAS system to address this shortfall.
Equipment in place to control and mitigate the risk of fire was sampled. During the plant walkdown, the inspection team considered there to be adequate fire extinguishers available around the entrance to Lab 54/54A and in adjacent rooms. Given the location of the fire annunciators and other constraints, including operators wearing air-fed suits and noise from the ventilation system, it was queried whether the fire alarm was audible. Shortly after the inspection Sellafield Ltd provided confirmation that an audibility test had taken place and audibility was found to be acceptable.
The positioning of activity in air samplers was reviewed during the plant walkdown and compared with the positioning stipulated within the safety case documentation. Activity in air samplers were present within the dressing/undressing area, the bagging out area and the adjoining C2 areas, consistent with safety case requirements.

Process - LC23 (Operating rules) and LC24 (Operating instructions)

The method statement sampled was clear, described the safety important tasks well and showed a golden thread through from the safety measures identified in the safety case. It was noted that this was not a continuous use procedure and instead hazards and protection measures would be reinforced prior to each task. This was considered pragmatic given PPE requirements and other conditions when undertaking the work.
The pre-job brief sampled was found to contain the operational measures identified in the safety case. This pre-job brief will be delivered prior to each entry to reinforce understanding of hazards and protection measures.
An Operational Schedule was sampled which linked safety case outputs (designated operational and engineered safety measures) with operational documentation. One required Operating Instruction was sampled and it was evident that linkage worked well and the rOI was present in the Method Statement.
The fire risk assessment for the work was sampled. The inspection team considered that the content addressed the key risks associated with fire associated with operations in Lab 54/54A, both in terms of life safety and nuclear fire safety.
The IRR17 Local Rules developed for the C5 and C3 areas were reviewed. They were found to contain the required information, including dosimetry, PPE/RPE and the main working instructions to ensure radiological protection in the areas.
During the plant walkdown the inspection team requested that Sellafield Ltd explain the procedure for operators exiting the C5 area. Sellafield Ltd confirmed that a procedure had been produced for this which included Health Physics Monitors and Safety Equipment Workers assisting the operator remove the air-fed suit. Reviewing the procedure, the team were content that it enabled good contamination control and radiological protection of operators and support staff.