Office for Nuclear Regulation

Compliance inspection of LC25 and LC32 at MDF

Executive summary

Purpose of Intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee (Sellafield Limited (SL)) against a strategy defined by the ONR Sellafield, Decommissioning, Fuel and Waste (SDFW) Division. The planned inspection schedule for 2020/21, updated as a result of the COVID-19 Pandemic, identifies the Licence Conditions (LCs) that will be inspected during this period. The selection of Mixed Oxide Demonstration Facility (MDF) was driven by the inventory of nuclear materials stored, some in modern standards, well controlled storage, but some historic material (e.g. carbide fuel) with less certainty in the condition and inventory.

The purpose of this inspection was for ONR to determine the adequacy of the implementation of SL’s arrangements for compliance with LC25 (Operational records) and LC32 (Accumulation of radioactive waste) at MDF. 

Interventions Carried Out by ONR

The inspection was carried out against ONR’s expectations for LC25 and LC32. ONR sought sufficient evidence of compliance to allow an inspection rating to be allotted in each case.

Due to the current coronavirus (COVID-19) pandemic, the intervention followed a blended approach involving a mixture of remote engagement supplemented by an on-site inspection. The inspection was carried out in line with the ONR SDFW Division’s regulatory approach to the COVID-19 pandemic and relevant COVID-19 risk assessments.

The inspection began with a teleconference between the inspection team, representatives from MDF, the SL internal regulator, and the Environment Agency. This session was supported by evidence that had been requested in advance of the meeting. Further evidence was requested and provided by SL following this session prior to the final stage of this intervention, which was an on-site inspection of the facility. Regulatory judgements have been made based on the verbal answers provided, the observations made on the site visit and the sampling of evidence provided by SL.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable since this was not a System-Based Inspection.

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

No significant matters were identified that required immediate regulatory attention.

From LC25 perspective, we sampled documentary evidence of inventory records relevant to fissile material, glovebox and Low Level Waste (LLW), as well as maintenance and testing records. The records were readily accessible and available for inspection. We also observed that the SL staff involved understood the local arrangements in place.

SL recognised that there is a gap within the records for the fissile and glovebox inventories and to address this gap is currently developing a PCM safety case, as part of its overall improvements programme at MDF. Full implementation of the arrangements for LC25 at MDF is ongoing. The internal regulator has already an interest in this area (specifically to LC6 - Documents, records, authorities and certificates) who is to oversee completion of this during the next financial year.  We judged that the significance of the shortfall was minor and were content for SL to address through the work of their internal regulator.

We sampled implementation of the arrangements under LC32 “Accumulation of radioactive waste” through reviewing information relating to SL’s strategy for management of radioactive waste.  This included the ongoing work against current ONR Regulatory Issues, formal Hold Points and outcomes from the most recent Long Term Periodic Review (LTPR).

SL recognised that operational limitations within MDF had constrained their ability to carry out activities enabling full compliance with LC32. However, the facility is currently undertaking an improvement programme, with several parts delivered via Hold Points, which will also address this shortfall. The facility has already made significant improvements and these were recently reported in two compliance inspections in July and September 2020.  The extent of the compliance gap with LC32 is considered minor given the limited activities being performed within MDF. 

One minor shortfall (Level 4 Regulatory Issue) was identified against the implementation of arrangements for LC32 at MDF.

Conclusion of Intervention

On the basis of the sampled evidence and observations made during the site visit, the inspection team judged that MDF had achieved an adequate level of compliance with ONR’s expectations in respect of LC25 and LC32.

ONR identified one minor shortfall that was captured in Level 4 Regulatory Issue (the lowest level) that will be followed up as part of routine regulatory business.  No significant matters were identified that required immediate regulatory attention and hence an inspection rating of Green (no formal action) was merited for LC25 and LC32.