Managing nuclear materials and spent fuels

We need to ensure the safe, secure and cost-effective lifecycle management of nuclear materials and spent fuels.

The NDA inventory of spent nuclear fuels is diverse and consists of large quantities of Magnox and oxide fuels, with smaller quantities of non-standard fuel types which we refer to as ‘exotic fuels’.

We are contractually committed to receive and manage all spent fuel arising from the seven EDF Energy AGR power stations in England and Scotland.

The UK holds large stocks of civil uranium and plutonium, much of which is managed by NDA.

Some of the nuclear material managed by NDA on behalf of customers is foreign-owned and remains the responsibility of its owners.

For UK owned plutonium the current government policy is safe and secure storage.


In 2011, informed by our strategic options work, the UK government proposed a preliminary policy view to pursue re-use of UK civil separated plutonium as Mixed Oxide fuel (MOX). This would see the vast majority of UK plutonium converted into fuel for use in civil nuclear reactors. Any remaining plutonium unsuitable for conversion into MOX would be immobilised and treated as waste for disposal.

The NDA undertook further work between 2011 and 2013. This focused on continuing to examine reuse of plutonium as MOX and an assessment of alternative reuse proposals (in CANDU or PRISM reactors) offered by two other technology vendors. This work culminated in revised advice to DECC in June 2013 and publication of a position paper in January 2014. The latest update on this work was published in March 2019.

NDA has continued to work with government to develop reuse options along with immobilisation as an alternative approach. Further work is needed to establish conditions so that a decision to implement a preferred option can be confidently made at the right time.

Only when government is confident that its preferred option could be implemented safely and securely, in way that is affordable, deliverable, and offers value for money, will it be in a position to proceed.


The current strategy is for uranic materials to be safely and securely stored indefinitely in existing (or replacement as required) facilities.

Owing to the diverse nature of our uranics inventory there is no single preferred management option for the whole inventory; the preferred option will need to be determined on a group-by-group basis.

The management options are:

  • continued safe and secure storage
  • sale to a third party for recycling and reuse
  • conditioning to an appropriate form for disposal

Continued storage does not provide an end point for this material. Uranics having commercial value be returned to the fuel cycle through sale to a third party.

Work is underway to define how uranic material with no foreseeable resale value could be disposed of to a Geological Disposal Facility (GDF) or an alternative facility.

Magnox fuels

The successful completion of defueling at Wylfa power station in September 2019 marked a hugely significant milestone in the NDA mission. The last of the NDA’s 26 Magnox reactors has now been defueled and the fuel transferred to Sellafield. The transfer of spent fuel to Sellafield for reprocessing results in a significant reduction in radioactivity and hazard at the reactor sites.

Our strategy is to reprocess all spent Magnox fuel in line with the Magnox Operating Programme (MOP9). Reprocessing is considered by the NDA and Sellafield Ltd to be the most underpinned and cost effective approach for spent Magnox fuel and has regulatory support.

The end of reprocessing is a landmark event for the NDA group. It brings to an end nearly 70 years of plutonium production and heralds the transition of the Sellafield Ltd business to clean-up, decommissioning and remediation. Sellafield Ltd expects the reprocessing of spent Magnox fuel to be completed by the end of 2020 and is planning on this basis. However, given the age of the facilities involved, there is a risk that plant under-performance or failure may prevent some of the fuel from being reprocessed during the predicted operational life of the existing facilities.

To address this risk, in our 2016 Strategy we explained that we would work with Sellafield Ltd on options so that any remaining fuel can be safely and cost effectively managed. We also highlighted that technologies to manage spent Magnox fuels are being developed as part of the programme to manage materials held within the legacy ponds at Sellafield.

Since then, Sellafield Ltd has built a new waste and spent fuel store, the Interim Storage Facility (ISF), which has been specially designed to hold containers of wastes and fuels recovered from the legacy ponds. Over the coming years, and subject to regulatory approvals, the wastes and fuels retrieved from the legacy ponds will be transferred into self-shielded boxes and into the new ISF. Following a period of interim storage, the wastes and fuels in the ISF are expected to be conditioned and disposed of to a Geological Disposal Facility (GDF).

Based on work recently completed by Sellafield Ltd, we have sufficient confidence that the same approach could potentially be used to manage any remnant spent Magnox fuel that it is not practicable to reprocess. Therefore, we have now adopted the use of self-shielded boxes as the contingency option for remnant spent Magnox fuel, with its implementation subject to regulatory requirements and permissioning.

Oxide fuels

In our previous Strategy we committed to undertake a study to determine how much spent fuel we should reprocess in THORP and how we should manage any remaining fuels including future arisings of AGR spent fuel.

We concluded that the delivery of the current strategy – to reprocess the contracted amount of spent fuel in THORP – remains the most viable and cost-effective option and confirmed our position in 2012. Following the closure of THORP in 2018 we plan to place the remaining AGR fuel into interim storage pending conditioning and disposal to a Geological Disposal Facility.

Exotic fuels

Exotic fuels are being transferred to Sellafield for management. Where possible the fuels will be treated using existing facilities, for example Dounreay Fast Reactor (DFR) fuel is being reprocessed alongside Magnox. Fuels which cannot be treated alongside other material will be safely and securely stored pending development of final disposition options.

Updates to this page

Published 8 April 2015
Last updated 30 September 2019 + show all updates
  1. Revised introductory text related to Magnox Spent Fuel.

  2. The latest update on plutonium was published in March 2019.

  3. First published.