Obtaining fissile material (i.e. high enriched uranium and plutonium) remains the greatest challenge to any new nuclear weapon programme. For more than 50 years, this recognition has underpinned both support for and opposition to the adoption of a binding international treaty banning the production of fissile materials for nuclear weapons or other nuclear explosive devices. Such a treaty, if effectively verified, would put a ceiling on the total amount of fissile material available for weapons and thereby deliver a number of important benefits:

• turn existing moratoria on the production of fissile material for nuclear weapons or other nuclear explosive devices announced by the US, Russia, UK and France into legally binding commitments
• place such a commitment on states that have not announced such a moratorium
• ensure verification arrangements were applied, eg. in the form of IAEA safeguards, to all enrichment and reprocessing facilities in nuclear weapons possessing states and on any fissile material they produced for peaceful purposes
• in the process put in place an essential building block towards an eventual global ban on nuclear weapons.

Negotiations of an FMCT

In May 2009, the Conference on Disarmament (CD) in Geneva agreed a Programme of Work which included a mandate for negotiations of a ‘non-discriminatory, multilateral and internationally and effectively verifiable treaty banning the production of fissile material for nuclear weapons or other nuclear explosive devices’.

The UK, along with other member states, continues to play a key role on this issue and fully supports the start of negotiations within the CD.

UK Activities on Fissile Material

The United Kingdom has already taken a number of practical steps in relation to fissile material:

• The UK (along with US, Russia and France) has declared a moratorium on the production of fissile material for nuclear weapons or other nuclear explosive devices.  

In the past the UK had produced high enriched uranium and plutonium for weapons purposes.  However, the UK announced in April 1995 that it had ceased the production of fissile material for nuclear weapons and other nuclear explosive devices. Accordingly, no such material has been produced since that date, though production of low enriched uranium and separated plutonium for civil purposes has continued.

• The UK has produced historical records of all our defence holdings of fissile material and placed stocks surplus to defence requirements under international safeguards.

In July 1998 the United Kingdom took the step of declaring the total size of the stocks of nuclear materials that it held outside international safeguards for national security purposes.  At the same time we announced that much of this stock was no longer required for defence purposes and that 4.4 tonnes of non-high enriched uranium would be placed under Euratom safeguards and made liable to inspection by the IAEA.

• We have also ceased exercising our right, as a Nuclear Weapon State, to withdraw fissile material from safeguarded stocks for nuclear weapons. Withdrawals are limited to small quantities of materials not suitable for weapons purposes and the details are made public. No material withdrawn from safeguards is used in nuclear weapons.