Explosive finale: energising EU-UK nuclear relations post-Brexit

When the UK finalized a trade and security agreement with the European Commission on 24 December last year, it left with a set of arrangements governing future energy cooperation.

Here, Dr David Lowry looks at the background and reveals one extraordinary condition that could terminate the nuclear component of the deal.

(CC BY 2.0, John Fielding)


An expert briefing by the House of Commons library in the UK Parliament set the context.

“On energy, although [EU] Member States remain ultimately responsible for security of energy supply to citizens, and for deciding their energy mix, the UK and EU energy sectors remain integrated through trade, legislation and interconnection of energy supply. Consequently, the future relationship between the UK and EU has the potential to affect the UK’s civil nuclear industry, including nuclear power and research, and the trade of electricity and gas through interconnectors. Additional areas that may be affected include the island of Ireland’s energy market, energy efficiency regulations, and general energy infrastructure through wider changes to trade and the movement of people.”

The British negotiating team set out its intended priorities in a document recently made public, in summary.

“The objectives of this Agreement are to recognise the [EU & UK] Parties’ respective commitments to combating climate change, to establish the bases on which the Parties shall trade natural gas, electricity and electricity interconnector capacity, to cooperate on trade in energy and to link their Emissions Trading Systems.”

“The UK’s future relationship with Euratom could have implications for the UK’s current nuclear operations, including fuel supply, waste management, cooperation with other nuclear states, and research..”

One of the complexities was the future arrangements for nuclear safeguards, which was addressed by a bilateral deal between the UK and European Commission, agreed in August 2018. Inter alia, it stated:

“ (…) This agreement is intended to replace an existing UK trilateral Voluntary Offer Agreement with the International Atomic Energy Agency (IAEA) and Euratom (the trilateral Voluntary Offer Agreement) (…). A key part of this programme has been to conclude a new bilateral agreement with the IAEA… signed on 7th June 2018 [which] provides the basis for the UK to continue to discharge its international non-proliferation and safeguards commitments…”

“As a nuclear­ weapons state, the UK has voluntarily accepted the application of IAEA safeguards subject to exclusion for national security reasons only. (emphasis added)

The Nuclear Safeguards Act 2018 provided the UK with the necessary primary legislation to ensure that the obligations in the voluntary offer agreement can be complied with.

Alongside the 1200-page Brexit trade and security agreement the UK and EU agreed a self-standing 18-page accord on nuclear co-operation, which is strong on outlining the importance of nuclear safeguards, peaceful uses of nuclear materials and  regulatory oversight.

There are several key sections dealing with nuclear materials, all of which are given a nuclear non-proliferation context by the preamble, includes the noting that the United Kingdom and all Member States of the Community participate in the Nuclear Suppliers Group;

The UK and EU agreed that “the objective of this Agreement is to provide a framework for cooperation between the Parties in the peaceful uses of nuclear energy on the basis of mutual benefit and reciprocity…the items subject to this Agreement shall only be used for peaceful purposes and shall not be used for any nuclear weapon or nuclear explosive device, nor for research on or development of any nuclear weapon or other nuclear explosive device or for any military purpose.”

The scope of nuclear cooperation] may take, but is not limited to, the following forms: the transfer of nuclear material…and exchange of information in areas of mutual interest, such as nuclear safeguards…

Article 6 cover Nuclear Safeguards, and explains that nuclear material subject to the  Agreement shall be subject to inter alia to  “the [UK] domestic safeguards system as implemented by the national competent authority”; and  to the IAEA safeguards pursuant to the United Kingdom‐IAEA Safeguards Agreement (INFCIRC/263).

Over 600 UK withdrawals of nuclear explosives from safeguards

The key thing to understand is what is permitted action under INFCIRC/263. Importantly, this Tripartite Agreement states at Article 14, headlined:


“If the United Kingdom intends to make any withdrawals of nuclear material from the scope of this Agreement for national security reasons in accordance with Article l(c), it shall give the Community and the Agency advance notice of such withdrawal. If any nuclear material becomes available for inclusion within the scope of this Agreement because its exclusion for national security reasons is no longer required, the United Kingdom shall inform the Community and the Agency thereof in accordance with Article 62(c).”

Nor was this provision a sleeping article, not applied by the UK, as the UK Government has stated in official disclosures that it has requested nuclear materials be removed from safeguards on more than 600 occasions since 14 August 1978, when the UK “voluntary” safeguards agreement entered into force.

Thus the new nuclear agreement between the UK and EU, allows the militarization of the entire 140,000 kilogramme stockpile of plutonium in store at Sellafield. For context, a nuclear warhead may be made with 5 kilogrammes.

Article 15 Administrative arrangements

  1. The Parties, through their respective competent authorities, shall establish administrative

arrangements to implement this Agreement effectively. Such arrangements shall include the

procedures necessary for the competent authorities to implement and administer this Agreement.

  1. Administrative arrangements established pursuant to this Article may be amended as

mutually determined in writing by the competent authorities.

  1. Administrative arrangements may provide for the exchange of inventory lists in respect of the

items subject to this Agreement.

  1. Administrative arrangements may set out the mechanisms for consultations between the

competent authorities.

  1. The accounting of nuclear material and nonnuclear material subject to this Agreement shall be based on fungibility (i.e. interchangeability) and the principles of proportionality and equivalence of nuclear material … as set out in the administrative arrangements established pursuant to this Article.

Then comes the most extraordinary Article in the entire agreement!

Article 22: Cessation of cooperation in case of serious breach. It states:

  1. In the event that:

(a) either Party or any Member State of the Community is in serious breach of any of the material obligations under Articles 1 [Objective], 5 [Items subject to this Agreement], 6 [Safeguards], 7 [Physical protection], 9 [Transfers, retransfers and facilitation of trade], 10 [Enrichment], 11 [Reprocessing] or 15 [Administrative arrangements], or any other obligations under this Agreement as may be mutually determined by the Parties in writing after consultations in the Joint Committee; or

(b) in particular, a nonnuclear weapon Member State of the Community detonates a nuclear explosive device, or a nuclear weapon Member State of the Community or the United Kingdom detonates a nuclear explosive device using any item subject to this Agreement, the other Party may, on giving written notification to that effect, suspend or terminate in whole or in part the cooperation under this Agreement.

(emphasis added)

In other words, the whole treaty can literally be blown up by a nuclear explosion!

The UK thus literally departed the EU with an atomic bang!


Guidance Published  24 December 2020

Nuclear Cooperation Agreements: implementation guidelines for operators from 2021


Technical guidance for nuclear operators on reporting requirements related to Nuclear Cooperation Agreements from 1 January 2021.

Brexit transition: new rules for 2021

The UK has left the EU. This page tells you the new rules from 1 January 2021.


Nuclear cooperation agreements between the United Kingdom and international partners: implementation guidelines for nuclear operators

PDF, 348KB, 21 pages

UK-Euratom nuclear cooperation agreement – notice

The Nuclear Safeguards (EU Exit) Regulations 2019





senior international research fellow at the Institute for Resource and Security Studies, Cambridge, Massachusetts USA

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