Fusion Scientists Seek to Save JET

October 18, 2023

Dear Fusion Colleagues,

Below you find a petition to form an international consortium to upgrade and extend the operation of the JET Facilities beyond 2023.

We invite you to sign this petition. We outline the scientific case to keep this unique multi-billion euro scientific infrastructure running, in support of ITER and fusion research in general for coming years.

Instructions on how to sign can be found after the petition text.

Petition to the the international fusion community, including UKAEA, EUROfusion, the ITER partners and other private or public parties involved in developing fusion as an energy source.

The JET facilities are unique in the world. JET has served as a test bed for new science and technology developments in support of ITER over the past decades. The dedication and expertise of the current JET team, JET's size, its metal wall, its unique tritium licence and facilities to operate D-T plasmas, its capability to characterise fusion born neutrons and alpha particles, all make JET an extremely valuable asset for the fusion community. Its potential for fusion research is far from exhausted as demonstrated by recent fusion energy records. Studies carried out with Tritium and Deuterium-Tritium plasmas are still ongoing and expected to continue to provide extremely valuable information for next step devices.

The current ITER re-baselining includes the installation of a full tungsten wall and increased ECRH power. In consequence, installing a full tungsten wall and an ECRH system at JET would mitigate risks for future ITER operations. Experimental open questions include, for instance, how to achieve fusion relevant ion temperatures (Ti > 10 keV) with dominant electron heating? how to optimise the transition to a high density regime with electron-ion equipartition? what is the impact of MeV-range alpha particles on plasma transport? how would boronization impact Tritium retention and plasma operation with a tungsten wall? would no-ELM regimes and/or impurity seeding work as a power exhaust solution for next step devices with a tungsten wall and divertor?

Refurbishing and upgrading JET such that it can operate until ITER (or other large-scale facilities) is ready would attract young talent to fusion, maintain and transfer essential know-how, and create and train an international team ready to optimise operations in next step devices. JET, an already operating facility, could provide essential information in a short time, to be adopted by future devices as they come online.

The closure of JET at the end of this year would therefore signify a serious scientific blow with a major negative impact on worldwide fusion research.

This is not the first time that JET's future has hung in the balance. Each time in the past, its unique characteristics have prompted fusion leaders to find new ways to make it fit for new challenges. Now is the time to take a bold step forward and start the international phase of JET. EUROfusion led such an effort in 2016. This could now be used as a starting point to develop a strong proposal. Circumstances have changed radically since then: ITER is redefining its plans, and the JET facilities now belong to UKAEA. Let us reconsider the internationalisation of the JET facilities to close the gap between medium-scale tokamaks and next-stage devices, complementing international on-going initiatives.

We, individual fusion researchers, call on UKAEA to invite the international fusion community to form a consortium to define a scientific case and develop a project for the renewal of JET. We call on Europe to join this effort and offer access to JET data to contributing consortium members. We call on all international fusion groups to join forces to make this visionary goal a reality.

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