PROGRESS ON PLUTONIUM CONSOLIDATION, STORAGE AND DISPOSITION March 2019 BACKGROUND OVERVIEW OF THE MANAGEMENT AND This paper provides an update on the NDA’s DISPOSITION OF PLUTONIUM IN THE UK progress on developing and implementing the UK’s plutonium management strategy in line with One of the most complex challenges facing the UK government policy. NDA in dealing with the UK’s nuclear legacy is the management and, ultimately, disposition of the This work covers three distinct areas of focus: inventory of separated plutonium held in the UK Consolidation, Safe and Secure Storage and (ref.1). The inventory has arisen from large-scale Disposition. reprocessing of spent fuel from both UK Magnox • Consolidation: and AGR power stations but also from overseas The NDA has taken the strategic decision to energy utilities under historical commercial consolidate the Dounreay plutonium inventory agreements. at Sellafield, the UK’s centre of excellence for plutonium management, where it can be The safe and secure management of civil better managed, and enable progress towards separated plutonium is a UK government priority. decommissioning and remediation of the Continued, indefinite, long-term storage leaves Dounreay site. a burden of security risks and proliferation sensitivities for future generations to manage. • Safe and Secure Storage: The UK government, working with the NDA, The NDA is ensuring the continued safe and aims to identify a solution that puts the UK’s civil secure storage of plutonium in the UK by plutonium beyond reach. This could be reuse as repacking the material for placement in a suite Mixed Oxide Fuel (MOX) in nuclear reactors or of modern stores, allowing time to develop as an immobilised product. This would put the and implement the right long-term disposition material in a form which both reduces the long- solution. term security burden during storage and ensures it is suitable for disposal in a Geological Disposal • Disposition: Facility (GDF). Implementing a long-term solution The NDA is supporting the UK government in for plutonium is essential to dealing with the UK’s the development of a long-term disposition nuclear legacy. solution to put separated plutonium beyond reach. 2 PLUTONIUM MANAGEMENT AND DISPOSITION PROGRAMME Objective: Ensure all separated plutonium is stored on one site, in a small number of facilities where it can be better CONSOLIDATION managed Activities: Transfer all of our plutonium stocks to Sellafield Objective: Ensure the safe and secure storage of SAFE AND plutonium in stores with enhanced resilience measures SECURE Activities: Repack and retreat plutonium packages to allow STORAGE time to implement the right long-term solution Objective: Support government in developing a long-term DISPOSITION: solution to put separated plutonium beyond reach THE LONG-TERM SOLUTION Activities: Work with government, developers and technology suppliers on reuse and immobilisation options The inventory of plutonium in the UK has arisen from the large-scale reprocessing of spent fuel. Reprocessing separates spent fuel into uranium, plutonium and waste products. 3 4 CONSOLIDATION THE CONSOLIDATION OF THE UK’S and the IAEA. Following the UK’s exit from CIVIL SEPARATED PLUTONIUM INVENTORY the European Union, the ONR will take over AT SELLAFIELD responsibility for ensuring UK compliance with these agreements (ref.3 and ref.4). Reprocessing separates spent nuclear fuel into uranium, plutonium and waste products. Following engagement and consultation in The end of spent nuclear fuel reprocessing 2012, the NDA took the decision to transfer at Sellafield began with the completion of the the plutonium inventory currently held at THORP reprocessing programme in 2018 Dounreay to Sellafield (ref.5). This means that and will be followed by the closure of Magnox all significant stocks will ultimately be stored reprocessing in 2020. The NDA will hold an at Sellafield, the UK’s centre of excellence inventory of around 140 tonnes of separated for plutonium management. It also enables plutonium by the time reprocessing finishes progress towards the decommissioning and (ref.2). Nearly all of this is held at Sellafield, remediation of the Dounreay site. with a relatively small amount at Dounreay. About 23 tonnes is foreign-owned, largely but The NDA initially proposed construction of a not exclusively by Japanese utilities, and is specialised facility at Dounreay to package managed under long-term contracts. materials for transport to Sellafield. Recently, under a modified approach, material is Due to the radioactive and fissile nature of instead being shipped directly to Sellafield, for the material, plutonium handling and storage treatment and repackaging, before transfer requires specialised facilities and stringent to the modern Sellafield Product and Residue management arrangements. The independent Store (SPRS) for long-term storage. This avoids Office for Nuclear Regulation (ONR) is the requirement for a specialised facility at responsible for regulating nuclear safety and Dounreay and makes best use of the Sellafield security across the UK and its inspectors ensure expertise in managing plutonium. that site licensees (Sellafield Ltd and Dounreay Site Restoration Ltd) meet these stringent We consider that this new approach offers requirements. The plutonium inventory held by the best balance of safety and delivery and NDA is stored in line with the requirements of allows the packages to be treated where there the International Convention on the Physical is the greatest expertise and management Protection of Nuclear Materials. experience. Sellafield Ltd has already developed a number of facilities for handling The stored plutonium can only be used for this material and is in the process of further peaceful purposes, and is managed in strict developing these capabilities to enable the accordance with the UK’s voluntary International delivery of the mission. The NDA will prioritise Safeguards agreements with the International the management and treatment of these Atomic Energy Agency (IAEA) (ref.2). The materials when they are consolidated at inventory is closely monitored by EURATOM Sellafield. It will take several decades to implement a solution for plutonium. In the meantime, therefore, we have decided to consolidate all of the inventory on one site. 5 STORAGE UNDERPINNING LONG-TERM SAFE AND Store Retreatment Plant, abbreviated to SRP, this SECURE STORAGE facility will repackage, and where appropriate, retreat, all of the plutonium packages. Due to the size of the plutonium inventory, any Based on current estimates this facility is long-term disposition solution will take many expected to become operational in less than decades to implement. In the meantime, the 10 years and to operate for nearly 40 years. NDA strategy is continued storage in a suite of custom-built facilities that ensure its safety and The NDA has evaluated the need for the new security in line with regulatory requirements. repackaging plant, SRP, in the context of the long-term plutonium disposition options under There are a number of plutonium stores on the development and concluded that, irrespective Sellafield site. Over the past decade, materials of which option is chosen, this new capability is have continued to be retrieved from older stores required to ensure continued safe and secure and consolidated in more modern state-of-the storage. art facilities such as the Sellafield Product and Residue Store (SPRS). The aim is to transfer all MANAGEMENT OF LEGACY PLUTONIUM plutonium into the SPRS store and its extensions FACILITIES AND PACKAGES over the next few decades. To ensure that the plutonium packages can be safely stored in The first-generation plutonium plants and stores SPRS, they will be repackaged and, where at Sellafield were built in the 1950s to support appropriate, some plutonium will be treated to reprocessing operations. The NDA considers be made compatible with long-term storage. In some of the older plutonium facilities used for some cases treatment is necessary to remove manufacturing and storage to be amongst the contaminants which can reduce the lifetime of the highest hazards on the Sellafield site, comparable packages. with the legacy ponds and silos facilities (ref. 6 and 7). A major, new specialised facility to repackage materials is required to support this strategy. The condition of some of these plutonium facilities Known as the Sellafield Product and Residues and some of the packages held within, is such 6 STORAGE that urgent action is required to reduce the risk Due to the requirement to reduce risk, and to with them. ensure their continued safe management most of these containers will be repackaged in existing A programme of work was therefore instigated plants. When the new SRP plant becomes to retrieve these materials from older stores and available the contents of these containers will consolidate them in more modern stores, and is be treated and then repackaged into containers now largely complete. suitable for long-term storage in the modern SPRS store. A major programme of asset care has also been undertaken at these legacy facilities to This programme of work is receiving enhanced support operation until they can be taken out regulatory oversight, and Sellafield Ltd is working of service and decommissioned. Sellafield Ltd with the ONR to complete this work promptly. has introduced enhanced package inspections programmes and identified categories of containers, in particular some of the oldest ones, which