Petition to extend JET beyond 2023

Contact the author of the petition

Update on JET petition: EU response

2024-05-18 19:03:08

Dear JET petition supporters,                  SmallJETphoenix3.png

     We haven't been in touch for quite a while, but we haven't been idle. On April 18, 2023, we sent letters to the European Commissioners that we thought would have an interest in changing the decision to close down JET.

     Letters were sent to (follow links to be redirected to each letter):

  • Mr. M. Šefčovič, Executive Vice-President for the European Green Deal, Interinstitutional Relations and Foresight
  • Monsieur Th. Breton, Commissaire Européen en charge du marché intérieur, de l'industrie, de l'entrepreneuriat et des PME
  • Ms. K. Simson, European Commissioner for Energy
  • Ms. I. Ivanova, European Commissioner for Innovation, Research, Culture, Education and Youth  

    A reply came from Ms. Rosalinde van der Vlies, Clean Planet Director in the European Commission, RTD C  

    Basically, we are being told again and again that the decision was already made, and JET now belongs to the UK. The new ingredient is that now we are informed that “the Commission is already implementing an ambitious fusion energy roadmap, to which its entire fusion budget is allocated. This includes contributions to ITER, the Broader Approach activities with Japan (and specifically the exploitation of JT60-SA) and the construction of IFMIF/DONES in Spain, and support to the EUROfusion co-funded partnership through the Euratom Research and Training Programme. In this context, therefore, the Commission cannot continue to support JET exploitation.”

    They confuse “cannot” with “will not”. Our message on the contrary is very clear: JET is presently the best tool for fusion expertise development, while its termination is a threat to the whole international fusion programme. The UKAEA would be willing to consider continuing operation with external funding. We are dismayed that they bluntly ignore those important messages in our carefully written letters. We would regret having to conclude that possibly we have been too polite, but we have the impression that this is indeed the case.

      We now ask you, petition supporters, to let us know what you think we should do next. We plan to send a robust but diplomatic reply to the letter of Ms. van der Vlies this week (20-25th May 2024), maybe with von der Leyen in cc. We are aware that with elections around the corner in both UK and EU, it’s difficult to get the attention of people further up the ladder. Maybe in the next letter we should aim for the top? A letter to both von der Leyen and Sunak, copies to the press? If so we would need UK and EU citizens willing to sign such letter as individuals, publicly. Until now we kept our efforts on the EU side, although we are aware of some individual initiatives within the UK. 

      Additionally we are working on the EPS poster proposing a future JET research programme. If you want to contribute to that please let us know what content you can provide (text, figures, references). The abstract can be found here   

The JET Petition Team



Urgent: help with signatures for letter to EU Commissioners

2024-04-17 11:36:05

Dear JET extension petition supporters,

Sorry for the long silence. We have been drafting a letter to be sent to EU Commissioners, above the level of those who have replied to us so far (DG). We think the letter would be better received if it had some notable signatures.

In the letter we describe the value of JET to the EU fusion programme and ask that the decision to terminate its operation be reviewed. We note that JET can still be saved (confirmed this Monday), but only with full funding from outside the UK.

We would like to have a number of signatures from EU fusion experts at the bottom of the letter. We know that some EU labs have explicitly told people not to sign such a letter. We are aware of a level of pessimism in the community but we think it is important we at least try to do the right thing.

If you want to help, please get in touch with us and we'll send you the draft. Send an email to 

                    jet.petition.2023 at 

as soon as possible. We must send the letter this week, ahead of some important meetings of the EU.

The JET petition team, JETforFusionSmallJETphoenix2.png


An update on JET: EPS abstract

2024-02-12 18:25:22

Dear supporters of the petition to extend JET operation,

As you may have seen in earlier announcements, we still have a way to go to achieve our goal. 

We have decided to submit an abstract to the 50th EPS Conference on Plasma Physics, describing a potential JET research programme. You can find the text below.

If you would like to contribute to develop the poster please get in touch.

Potential research programme for JET

E.R. Solano1, J.Ongena2, JET petition supporters*

1Laboratorio Nacional de Fusion, CIEMAT, Madrid, Spain; 2Laboratory for Plasma Physics, LPP-ERM/KMS, Brussels, Belgium;*Petition to extend JET beyond 2023

We present a potential staged research programme for the JET facilities, focusing on JET’s unique capabilities, with a 10 year horizon. Stages A, B, C consist of short experimental campaigns, to enable maintenance of the facilities in between campaigns (sorely needed), to maintain and develop team know-how and to prepare the significant upgrades for Stage D. Select experiments from early stages can be developed in later stages.

Stage A, using the existing JET configuration in Deuterium plasmas as is. Obvious candidates are experiments not executed or finished in earlier campaigns due to tight deadlines. Just to mention a few: develop Ne and Ar Baseline seeded plasmas; test ITER-relevant plasma and tokamak control tools; investigate operation without cryopump to mimic ITER’s particle balance; test/validation of EFCC models for ELM control; continue Negative Triangularity work; develop QH-mode plasmas; investigate pellet fuelling in hot pedestal with pacing pellets; optimize the Hybrid scenario (raise δ), investigate L-H transition, etc…

Stage B would include minor upgrades, diagnostic recovery and enhancements: new pressure gauges, develop α-particle diagnostics for ITER (with B + 4He γ-ray reactions).

Stage C (optional), T and/or DT short campaigns: specifically, test T RF heating schemes for ITER; explore 3He minority ICRH in D plasmas and 2nd harmonic T heating in DT and T plasmas (as in ITER). Selected experiments from earlier stages may continue here.

Stage D, with a W wall, Boronization, 10 MW of ECRH: 170GHz gyrotrons, as in STEP and ITER. Development and validation of scenarios in the new ITER-relevant domain; tests of ELM control/mitigation/suppression; investigation of EC, IC, NBI, a-heating synergies towards higher performance scenarios with Te=Ti (optionally with controlled seeding); investigate Ti clamping as function of ratio of e and ion heating. Aim for steady Q = 1 with D-NBI injection into a T plasma, combined with ICRH and ECRH. Mitigating operational risks for ITER necessitates both targeted experiments and the training of the next generation of scientists, technicians, and engineers in a large fusion facility. An extended operation of the Joint European Torus (JET) is the ideal vehicle for such studies.

The JET Petition Team



Response from the European Union

2023-12-22 08:09:58

On 30/11/2023 we received the following response from the EU, signed by Marc Lemaître, Director-General for Research & Innovation and  Ditte Juul-Jørgensen, Director-General for Energy.

We are grateful that our petition has merited their attention. Unfortunately the petition organisers were quite busy with the last few experiments at JET and only now did we find the time to post this announcement. We hope to reply to all authorities during the next few weeks.

Dear petitioners,

We would like to thank you for your petition to extend the Joint European Torus (JET)
facilities beyond 2023.

The history of JET is a continuous series of success stories. It is a testimony to the vision and competence of the European fusion community that proposed, designed, and financed the facility back in the 1970’s, and operated it for the last 40 years, despite many technical, administrative and political difficulties.

Following the decision to install an ‘ITER-like wall’ 14 years ago financed by Europe, JET has been devoted 100% to support ITER. The ITER design is evolving, and the world fusion community must continue to support design changes. Extending the operation of JET to validate the latest ITER design evolution, in particular a full tungsten wall and a dominant electron cyclotron heating, would require about ten years and about €1 billion, as explained by Prof. I. Chapman in his answer to you. Moreover, as recalled by Prof. A. Fasoli and T. Donné in their answer, EUROfusion proposed in 2016 an internationalisation of JET that would have secured its future. This proposal did not garner the international community's support, and Europe alone cannot continue to provide the required support.

Euratom has a significant program for fusion R&D beyond JET. The knowledge acquired during the last 40 years, the availability of more recent machines, and the appearance of new stakeholders in the fusion landscape, among others, have led Euratom and its many
international partners to plan future activities without JET. Indeed, given the present situation, the resources required for another major upgrade of JET and its exploitation can be invested in other relevant scientific programs. For the EU, these are all specified in the Euratom work
programmes. Beyond ITER, which requires significant resources, Euratom programs foresee the support for the construction of new facilities in Europe, namely DONES and DTT, the scientific exploitation of existing and newly commissioned fusion devices, in particular JT60-
SA, developed in collaboration with Japan, the official inauguration of which is scheduled on 1 December later this year, and the setting up of a public-private partnership to join forces with the private sector.

Lastly, we would like to recall that the United Kingdom withdrew from the European Union and Euratom in 2020 and has recently decided not to join forces Europe’s efforts to develop fusion, particularly in support of ITER.

Despite this challenging political context, the EU has ensured financial support to JET until 31 October 2021 to complete the DTE2 experiments. Since that date, the responsibility and ownership for JET rest entirely with the United Kingdom.
We hope the above clarifies our position on the matters raised in your petition.
Yours sincerely,
Marc Lemaître 
Director-General for Research & Innovation
Ditte Juul-Jørgensen,
Director-General for Energy


Reply of Tony Donné and Ambrogio Fasoli, EUROfusion, to letter from petition representatives. Received 03/11/2023.

2023-11-07 12:48:00

Dear Dr. Hotchin, Dr. Solano, Dr. Sharapov, Dr. Lennholm, and Dr. Ongena,

Thank you for your email dated November 2, 2023, and for sharing the petition regarding the Joint European Torus (JET) facilities. We have carefully reviewed your letter and the voices of the 800+ fusion professionals advocating for the extension and upgrading of JET.

At EUROfusion, we deeply respect the passion and dedication to fusion research that these appeals represent. The Joint European Torus has indeed been instrumental in advancing our collective understanding and bringing us closer to the realization of sustainable fusion energy.

Given the current discourse on the future of JET, we believe it is important to share EUROfusion's positioning statement. This encapsulates our perspective, informed by extensive deliberations and assessments of the broader context of fusion research and the evolving needs of our scientific community. -----------------------------------------------------------------------------------------------------------------------------

EUROfusion's Positioning Statement on the Future of the Joint European Torus (JET)

In the dynamic and evolving landscape of fusion research, EUROfusion has consistently championed the pursuit of scientific advancement and international collaboration. The Joint European Torus (JET) has been a cornerstone of European fusion research, contributing invaluable insights and propelling the global community closer to the realization of sustainable fusion energy.

In 2016, recognizing the potential benefits of extending JET’s operational life in support of ITER, EUROfusion proposed an internationalization that would have secured its future. Regrettably, this proposal did not garner the necessary support of the international community at the time. Now, as we stand at a crossroads, we acknowledge the voices calling for JET's continued operation and deeply respect the passion and dedication to fusion research that these appeals represent.

However, we must also confront the present realities. Not only has the landscape of fusion research shifted significantly, but JET itself would require substantial investment for upgrades to continue operations—a process that would take years to complete. During this time, the facility would remain non-operational, delaying further research and advancements. Furthermore, the UKAEA has already initiated the decommissioning process of JET and reassigned its many researchers, technicians, and staff.

Given these factors, and our budgetary constraints, we must consider the broader portfolio of research facilities that also warrant support. With a future-oriented mindset, we need to look towards the future, not back to the past. This perspective is not a dismissal of JET's monumental contributions but an acknowledgment that the path to fusion energy requires us to adapt, innovate, and sometimes make difficult decisions.

Our focus now turns to ensuring that the legacy of JET is preserved. We are committed to safeguarding the wealth of knowledge and data accumulated, facilitating a seamless transition for the talented JET team, and continuing to drive fusion research forward through our existing and future initiatives.

EUROfusion remains steadfast in its mission to realise sustainable fusion energy. We are dedicated to fostering collaboration, supporting cutting-edge research, and advocating for policies that advance the fusion field. Together with our partners, we look to a future illuminated by the promise of fusion energy. -----------------------------------------------------------------------------------------------------------------------------

We understand that our perspective may not align with the desires expressed in the petition. However, please rest assured that our commitment to advancing fusion energy research and fostering international collaboration remains unwavering. We are dedicated to ensuring that the legacy of JET is preserved, and the expertise of its talented team is effectively integrated into future projects.

We are open to any further discussions or clarifications you might seek on this matter. Your insights and contributions to fusion research are invaluable, and we are committed to maintaining an open and constructive dialogue as we navigate this evolving landscape together.

Thank you once again for your dedication to the field of fusion energy and for initiating this important conversation.

Warm regards,    

Tony Donné – Programme Manager (CEO) EUROfusion and Ambrogio Fasoli – Chair and Programme Manager Elect of EUROfusion    


Update: dialog with UKAEA and EUROfusion. Includes message from Sir Ian Chapman, UKAEA CEO.

2023-11-06 15:20:20

Dear fusion leaders and authorities

We have now received a reply from Sir Ian Chapman, CEO of UKAEA. I attach it below. We have posted and re-sent the reply from Tony Donné, EUROfusion Leader, earlier, see Annoucement #3 on the petition web site .

From the point of view of this petition I would highlight Ian's statement "We are always open to potential collaborations, and if another partner brings forward a scientifically meritorious proposal with full finance, then we would discuss this, but we would need to receive such proposals very soon. "

We are grateful to Ian for opening up this opportunity. We note that also the letter from Tony Donné invites insights and contributions from the community. If any international fusion groups think there is merit to the proposal described in the petition, please inform Ian as soon as possible. Please keep us in copy.

For the time being we would like to separate the assessment of merit of the proposal from funding issues. We propose to install a W wall and gyrotrons at JET, and keep it alive for another ~10 years. We ask fusion leaders to inform Ian and ourselves of their views on this. Note the manty comments from petition subscribers: all support the proposal (894 signatures at the moment).

Ian is correct, we are describing a project likely to cost ~€100M/year for 10 years, although it can start with less. Gyrotrons, a W wall and dedicated personnel cost money.

Synergies with the UK and EUROfusion programmes may allow some funding from them, despite past decisions. But internationalization of JET may be key to unlock negotiations. And if private partners are interested, this could also prove to be very helpful.

First, let us agree on what would be desirable, beyond the present plans of UKAEA and EUROfusion.

Regards the JET petition team, jet dot petition dot 2023 at gmail dot com


From: Chapman, Ian T <>

Sent: Friday, November 3, 2023 3:02 PM

Subject: RE: Letter to Fusion Authorities, JET petition

Dear all

Thank you for your email and the passion that you clearly share for delivering fusion.

JET is a remarkable facility that has achieved remarkable things and demonstrated the benefit of many partners working together. Fusion would not be at the stage it is today without JET. ITER would not be happening, so many discoveries would not have been made, a generation of fusion experts would not have been trained and we would not have confidence to be moving forward with designs for fusion powerplants. JET has already operated for decades longer than originally anticipated due to the ingenuity and prescience of the team.

However, at the same time, we must plan for the future of fusion. Extending JET operations without upgrades would lead to only incremental science and therefore is not worth the substantial annual running costs of the facility. Enacting upgrades such as the ones you describe, whilst scientifically valuable, would take of order ten years to design, build, commission and then scientifically exploit. This would cost of order £1Bn as well as leading to greater decommissioning liability. These are costs that will not be borne by the UK government. The UK government’s fusion strategy is clear that we plan for decommissioning and repurposing of JET whilst at the same time substantially investing in the fusion sector through many new research facilities, a prototype powerplant programme and growth in the fusion industry. Cessation of JET operations is not a cause for despondency, but a transition towards an exciting future with many new facilities, research programmes and a clear mission to deliver fusion power.

In line with the government’s published fusion strategy (Towards Fusion Energy 2023: The next stage of the UK’s fusion energy strategy (, UKAEA will begin the decommissioning and repurposing of JET from 1st January 2024. We have already discussed extension of JET operations at length with our EUROfusion partners who agree that it is time to plan for a future without JET. Indeed, eight years ago we discussed major upgrades to JET with the international community, exactly as you propose, but at the time when decisions for major upgrades needed to be taken. Unfortunately, we could not secure agreement for enhancements with the international community and so it was eventually decided at the EUROfusion General Assembly (with the UK in agreement) to plan for the end of scientific operations in 2023. We are always open to potential collaborations, and if another partner brings forward a scientifically meritorious proposal with full finance, then we would discuss this, but we would need to receive such proposals very soon. In the meantime, we are focussed on planning for decommissioning, itself an exciting programme essential for the future of fusion, and as such we do not have any spare resource to work on alternative plans.

Regards Ian


Prof Sir Ian Chapman FRS FREng FInstP HonFNucl

Chief Executive Officer United Kingdom Atomic Energy Authority


JET petition in Physics World

2023-11-04 08:12:22


Letter to Fusion authorities, 2nd November 2023

2023-11-02 14:28:14

Esteemed international fusion leaders:

We write to you representing the fusion professionals that have signed the petition to enable the use of JET facilities for DT operations well beyond 2023, petition_to_extend_jet. The petition was launched on October 16th 2023, after the ITER talk at IAEA FEC describing ITER’s new plans: a tungsten wall and dominant electron cyclotron heating.  Such a dramatic ITER move changes the timeline of magnetic fusion significantly. The closure of JET in 2023 seems now premature as it would result in a skills’ shortage, and technological and scientific gaps: no equivalent fusion DT plant will be available for many years to come. Rather than closing JET at the end of 2023 and decommissioning it from 2024 (as presently planned by UKAEA), we propose the installation of a tungsten wall in JET and an ECRH system in JET,  as an international collaboration.

The signatories' comments emphasize that JET is one of the most valuable assets in present day fusion, largely from its irreplaceable DT capabilities. The fusion world would benefit from using the existing JET infrastructure and facilities as an international fusion facility, with DT capabilities, a W wall and ECRH. This would provide relevant and timely experimental data from a large machine and a testbed for technology, in support of ITER and future fusion reactors anywhere in the world.

The petition has been signed by more than 800 fusion professionals in less than 3 weeks. We would highlight signatures from Paul-Henri Rebut, who built JET, Osamu Motojima, former Director of the ITER Organisation, and Jerome Pamela, former JET and EFDA Leader, amongst many others.

In consequence, representing the signatories, we address this letter to the relevant fusion authorities, with the following requests:

1.    We ask the UK, the EU and the ITER Organization to evaluate the benefits of upgrading and operating JET.

2.    We ask the UKAEA, current owner of the JET Facilities, to invite expressions of interest from the international fusion community.

3.    We ask the international fusion community, including the ITER partners, private companies and industry, to proactively inform the UK and the EU of their interest in joining such an endeavour, specifying what they might contribute: expertise, hardware, funding. Please send such expressions of interest and proposals to the CEO of UKAEA, Sir Ian Chapman, and to the EUROfusion Programme Managers Dr. Tony Donne (2023) and Dr. Ambrogio Fasoli (from 2024), adding authorities you find appropriate in copy. We would be grateful if a copy of such expressions of interest could be sent to jet.petition.2023 at gmail dot com

Yours sincerely,

Simon Hotchin, Tokamak Operations Manager, UK

Emilia R. Solano, JET scientist, Madrid, Spain

Sergei Sharapov, JET scientist, UK

Morten Lennholm, Senior Plasma Control Expert, STEP, UK

Jef Ongena, JET scientist, Brussels, Belgium

representing the signatories of the petition, all of whom signed as individual fusion professionals, not representing the views of any institution.

Attachments: Excel with signatures up to noon 2 Nov 2023, PDF with Letter and Recipient list.

Additional information can be found in the petition web page, https://www.petitions. net/petition_to_extend_jet




DG: Rafael Grossi 

Senior Advisor to DG: Diego Candano-Laris  



CEO: Sir Ian Chapman              

Board Chair: Lady Eithne Birt

Deputy CEO: Tim Bestwick


CEO:  P. Methven

Board Chair: David Gann



Director: Pietro Barabaschi

ITER Domestic agencies: please forward to suitable contacts within the countries you represent, if not already listed.

Chinese Domestic Agency: T Fang      

European Domestic Agency F4E

Director: Marc Lachaise

Board Chair:  Carlos Alejaldre


Project Director: Ujjwal Baruah

ITER Japan Domestic Agency:

              Head: M. Sujimoto

Deputy Head: T Inoue

ITER Korea:

Head: HG Lee

ITER-Russia Domestic Agency

Head Anatoli Krasilnikov

US ITER Project

Director: Kathy A McCarthy



Programme Manager (2023):  Tony Donné

Programme Manager (from 2024): Ambrogio Fasoli

EUROFUSION Heads of Research Units, added in bcc.

European Commission:

EURATOM Research Head: Elena Righi-Steele

DG ENER Commissioner: Kadri Simson

DG ENER DG : Juul-Joergens

DG ENER Deputy DG:  Massimo Garriba

DG RTD Commissioner: Iliana Ivanova 

DG RTD Director General: Marc Lemaitre         


USA contacts, DOE:

Associate Director Office of Science, Fusion Energy Sciences: JP Allain

Senior Advisor and Lead Fusion Coordinator: Scott C. Hsu


JET petition press release

2023-10-20 15:52:56
Fusion researchers from all over the world call on the UKAEA to invite the international fusion community to find a way to suitably upgrade JET and continue operations.

The UK and the world fusion programmes, including STEP and ITER, would greatly benefit from JET renewal: it would help maintain know-how and provide training opportunities for the next generation of fusion experts in the largest magnetic confinement fusion experiment in the world.

More than 500 experts have signed the petition in the last five days. P-H. Rebut, who built JET, is amongst the most notable supporters. Many of the signatories are attending the IAEA Fusion Energy Conference in the Queen Elizabeth Centre in London. It will close tomorrow at 5 pm.


Group photo this noon 12:30

2023-10-20 05:26:24

Dear supporters of the JET petition:

thank you very much for signing in such numbers. In 4 days we got more than 450 signatures! Not bad. But we need more to strengthen further our case. Do encourage your colleagues to sign this week, please.

For those of us who are at IAEA FEC, we propose to get together for a group photo tomorrow Friday at 12:30. We will meet at the ground floor of the Queen Elisabeth Convention Centre, near the door, on the side away from the cafe. If it's not raining we can move outside.

It would be wonderful if we could get a large enough group.

Beware we might release the photo to the media. 

We hope you'll join us!

See you tomorrow!




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