Office for Nuclear Regulation

Capenhurst TMF Project - Tails De-conversion Plant (TDP) readiness inspection

Executive summary

Purpose of Intervention

This was the main readiness review and inspection in support of ONR issuing an agreement to commence active commissioning of the Tails De-conversion Plant (TDP) that forms part the Tails Management Facility (TMF) at the URENCO UK Ltd nuclear licensed site. 

Interventions Carried Out by ONR

The by-product of uranium enrichment is depleted uranium hexafluoride, known as “Hex Tails”.  A new facility, the Tails Management Facility, has been constructed on the URENCO UK Ltd’s Capenhurst site to convert tails to a chemical form more suitable for long-term storage.  The TMF will be operated by, Urenco ChemPlants Ltd (UCP), a tenant on the Capenhurst site, but owned by the parent company URENCO.

This inspection was carried out by a small team of inspectors to determine the adequacy of implementation of the safety case claims in respect of the TDP, and is part of an ongoing programme of inspections and assessment of UCP’s readiness to commence active commissioning of the TDP, which is subject to an ONR regulatory hold-point.  ONR examined evidence to determine compliance against seven Licence Conditions (LCs).  These LCs were selected in view of their importance to nuclear safety and in providing a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.

ONR assessed compliance against the following LCs:

The inspection examined the applicable safety case claims, through a combination of document reviews, discussions with plant operators, internal nuclear assurance and plant inspections to determine compliance against the selected LCs.

The focus of this inspection was to ascertain whether the licensee’s and tenant’s licence condition arrangements would deliver nuclear safety when implemented and to ascertain whether further inspection(s) may be required prior to giving regulatory permission to commence active commissioning of the TDP.

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

From the areas targeted and the evidence examined during the inspection, ONR considers that UCP is adequately implementing those safety case claims that relate to the TDP.  However, there were some aspects identified by UCP that have implications for the active commissioning schedule, for which the root causes have not yet been identified.  ONR will monitor the progress with these identified shortfalls as part of its interactions leading up to issuing agreement to commence active commissioning and beyond.  There are also a number of minor observations made during the inspection for the licensee and the tenant to consider.

Conclusion of Intervention

From the evidence sampled during this inspection, it was judged that there were no matters that have a significant adverse impact on nuclear safety. The inspection findings were shared and accepted by UUK and UCP as part of post-inspection feedback. ONR considers UCP adequately demonstrated ownership and implementation of the TDP safety case to ensure and maintain nuclear safety.

ONR’s conclusion from the findings of the inspection is that the implementation of the TDP safety case is adequate so far.  However further inspection(s) that are required will seek confirmatory evidence that sufficient progress has been made in the areas described in the report prior to ONR giving agreement to commence active commissioning.