Office for Nuclear Regulation

Sellafield - LC 22 inspection of AGR Fuel Interim Storage at TR&S pond

Executive summary

Purpose of Intervention

This intervention, conducted at the Sellafield Limited (SL) licensed site in Cumbria, was undertaken as part of the 2018/19 Objective 4 Plan Task Sheet, to support the ONR permissioning decision for Advanced Gas Reactor (AGR) Spent Fuel Interim Storage.

Interventions Carried Out by ONR

I conducted a Licence Condition (LC) 22 (“Modification or Experiment on Existing Plant”) readiness inspection focused on the licensee’s arrangements for the implementation of its AGR Interim Storage (ASTOP) safety case at the Thermal Oxide Reprocessing Plant (THORP) Receipt and Storage (TR&S) fuel pond at Sellafield Ltd’s nuclear licensed site. This inspection was conducted to inform ONR’s judgement regarding the adequacy of the licensee’s arrangements for implementation of its safety case to support the upcoming permissioning decision for interim storage of spent AGR fuel.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

No matters were identified requiring immediate regulatory attention during the conduct of the inspection.

I sampled the licensee’s arrangements for implementing the safety case, with focus on the clearance certificate, operational arrangements, pH dosing systems, the 63c fuel storage rack, asset care and maintenance arrangements, the status of key safety documentation, and the internal control mechanisms in place to enable the safe commencement of interim fuel storage. SL was able to demonstrate that it had a clear understanding of the impact of the modifications to plant, processes, and people to support the commencement of the ASTOP safety case.

As the safety case is not going to be adopted until early 2019, a number of the documents / arrangements sampled were at the draft stage. I therefore also reviewed the licensee’s processes for completing these and was content that they are appropriate to implement the safety case elements based on the above sample.   

From my discussions with the licensee and examination of the relevant safety documentation, I am content that the licensee has derived learning from plant operating experience, previous events and industrial standards.  I judge the licensee’s arrangements to be adequate for successful implementation of the safety case, applying relevant good practice.

Based on the evidence sampled I am satisfied that the licensee has robust arrangements in place to manage the process of implementing the ASTOP safety case.

Conclusion of Intervention

Overall, I am satisfied that SL has appropriate arrangements to enable it to commence interim storage of spent AGR fuel in the TR&S pond. This inspection has demonstrated that SL has appropriate arrangements in place for implementing its safety case through the clearance certificate, to maintain the plant in a safe condition, to increase the pH in the pond to 11.4, implement the operation of the 63c rack, and internal hold points with independent oversight from the internal regulator.  I therefore consider, noting the ONR guidance on inspection ratings, that an inspection rating of Green (no formal action required) is merited here.