Office for Nuclear Regulation

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Spent Fuel Management - Thermal Oxide Reprocessing Plant compliance inspection

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 Sub Division.  In accordance with that strategy, compliance inspections were undertaken in February 2020at the Thermal Oxide Reprocessing Plant (THORP) against Licence Conditions (LC) 32 (Accumulation of radioactive waste) and LC 35 (Decommissioning).

The purpose of this planned inspection was for ONR to determine the adequacy of THORP’s implementation of the licensee’s formal arrangements for compliance with LC 32 and LC 35.

Interventions Carried Out by ONR

On 6 and 7 February 2020, I carried out two one-day licence condition compliance inspections of THORP.  The inspections comprised discussions with SL staff, reviews of plant records and other documentation and a plant inspection (LC32 only).  I was supported by the THORP Site Inspector, another Nuclear Liabilities Regulation (NLR) specialist inspector and a Nuclear Safety Inspector seconded from the Ministry of Defence.  This was a joint inspection with the Environment Agency (EA).  A member of SL’s Nuclear Intelligence and Independent Oversight (NI&IO) team also participated in the inspections.

The primary requirement of LC 32 is for the licensee to make and implement adequate arrangements to minimise, so far as is reasonably practicable, the rate of production and total amount of radioactive waste accumulated, and for recording the waste.

The primary requirements of LC 35 are for the licensee to make and implement adequate arrangements for the decommissioning of any plant or process that may affect safety, to make arrangements for the production and implementation of decommissioning programmes and to divide the decommissioning into stages.

As part of my preparation for the delivery of this intervention, the following ONR technical inspection guidance documentation was used:

Explanation of Judgement if Safety System Not Judged to be Adequate

This was not a system based inspection, and therefore no judgement has been made of the adequacy of implementation of any part of the safety case.

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

Prior to the inspection, I undertook a review of the relevant Sellafield procedures against the ONR guidance documents for LC 32 and LC 35.  From the areas sampled, I did not identify any significant shortfalls in the licensee’s formal arrangements for compliance with the licence conditions that would prompt an inspection of these arrangements earlier than currently planned.

During my LC 32 inspection, I sampled documentary evidence that supported the management of wastes arising on plant both as a result of ongoing activities and legacy waste/redundant equipment that will be required to be removed prior to the end of Post Operational Clean Out (POCO).  Additionally, I undertook a plant inspection to confirm the scope and extent of accumulated wastes on plant and to establish if the licensee is adequately managing the accumulation and safe storage.  I observed some discrepancies in the implementation of local arrangements for temporary laydown areas; the licensee agreed that the arrangements could be improved.  I judge this to be a minor shortfall that does not represent a significant reduction in safety and have therefore judged it proportionate to raise a Regulatory Issue to oversee progress on the improvement actions.

On the basis of the evidence sampled at the time of this inspection, I judged that the licensee has adequately implemented its arrangements for compliance with LC 32 (Accumulation of radioactive waste) at THORP.  I therefore consider that the required standard was met and an inspection rating of Green (No Formal Action) is merited.

During my LC 35 inspection, I sampled documentary evidence relating to progress with preparation and delivery of POCO activities.  I observed that the licensee has taken proactive steps to improve its arrangements based on learning from experience at THORP as the facility approaches the start of POCO.

On the basis of the evidence sampled at the time of this inspection, I judged that the licensee has adequately implemented its arrangements for compliance with LC 35 (Decommissioning).  I therefore consider that the required standard was met and an inspection rating of Green (No Formal Action) is merited.

Conclusion of Intervention

From the evidence gathered during this intervention, I do not consider there to be any matters that have the potential to impact significantly on nuclear safety.

At present, no additional regulatory action is needed over and above the planned interventions within THORP at the Sellafield Nuclear Licenced Site as set out in the Integrated Intervention Strategy, which will continue as planned.  I have raised a Level 4 Regulatory Issue to monitor progress with revising the local arrangements for control of temporary laydown areas.