Broader Approach agreement

Overview

The Broader Approach (BA) agreement is a strategic partnership in the field of fusion energy research between Japan and the European Atomic Energy Community (Euratom). Formally signed in 2007, the agreement established a framework for collaborative projects intended to accelerate progress towards a demonstration fusion power plant (DEMO). The BA runs in parallel with the ITER project and was a key component of the international negotiations that led to ITER being sited in Cadarache, France. In exchange for Europe hosting ITER, Japan hosts the facilities for the Broader Approach projects.

The collaboration focuses on three main areas, each with a dedicated project:

JT-60SA: A large, advanced superconducting tokamak in Naka, Japan, designed to support ITER operations and explore advanced plasma scenarios for future power plants.
IFMIF/EVEDA: The Engineering Validation and Engineering Design Activities for the International Fusion Materials Irradiation Facility, located in Rokkasho, Japan. This project develops and validates the accelerator technology required for a future neutron source to test materials under fusion-relevant conditions.
IFERC: The International Fusion Energy Research Centre, also in Rokkasho, which includes a high-performance computing center for plasma simulations and a center for DEMO design and R&D coordination.

These projects address critical gaps in the path to commercial fusion energy that are complementary to ITER's primary mission of demonstrating a burning plasma.

Programmatic Structure and Goals

The Broader Approach is governed by a Steering Committee with equal representation from Japan and Euratom, which provides strategic direction and oversight. Each of the three projects is managed by a dedicated Project Committee. The implementation is carried out by Japan's National Institutes for Quantum Science and Technology (QST) and Europe's domestic agency, Fusion for Energy (F4E).

The agreement is structured around shared contributions. Japan provides the sites, buildings, and a significant portion of the staff and operational costs. Euratom contributes primarily through in-kind procurement of high-technology components manufactured by European industry and research institutions. This model fosters technological exchange and strengthens the industrial supply chains in both parties.

The specific goals of the core projects are:

JT-60SA (Joint Tokamak-60 Super Advanced): To contribute to the early realization of fusion energy by addressing key physics and engineering issues for ITER and DEMO. Its objectives include sustaining high-pressure plasmas for long durations, establishing steady-state, high-beta operational scenarios, and managing plasma-wall interactions with a divertor configuration relevant to DEMO.
IFMIF/EVEDA (International Fusion Materials Irradiation Facility / Engineering Validation and Engineering Design Activities): To validate the key technologies for a deuteron-lithium (d-Li) neutron source. This involves constructing and operating prototype linear accelerators (LIPAc) capable of producing a 9 MeV, 125 mA continuous wave deuteron beam. The ultimate goal is to provide the technical basis for constructing a full-scale IFMIF, which is essential for qualifying structural materials for DEMO and future power plants.
IFERC (International Fusion Energy Research Centre): To advance computational science and DEMO design. The Computational Simulation Centre (CSC) provides supercomputing resources (currently the JFRS-2, or "Roku-chan") for large-scale simulations of plasma behavior and fusion technologies. The DEMO Design and R&D Coordination Centre fosters joint studies on the conceptual design of a demonstration power plant, identifying and coordinating necessary research and development activities.

Historical Development

The concept of the Broader Approach emerged from the international negotiations for the ITER site in the early 2000s. After a competitive process between several international partners, the choice was narrowed to Cadarache, France (proposed by Europe) and Rokkasho, Japan. To ensure continued strong Japanese involvement and to leverage its extensive fusion research infrastructure, the parties negotiated a parallel package of joint projects to be hosted in Japan. This agreement was crucial for achieving consensus on the ITER site.

The Broader Approach agreement was signed in Tokyo on February 5, 2007, and entered into force on June 1, 2007, for an initial period of 10 years. The construction and commissioning of the various project components progressed steadily throughout this period.

Key milestones include:

2007: Agreement enters into force. Construction begins at the Naka and Rokkasho sites.
2012: The IFERC supercomputer (Helios) begins operation.
2013: Assembly of the JT-60SA tokamak begins.
2017: The initial 10-year term concludes. The agreement is extended for three years to December 2020 to complete construction activities.
2018: The LIPAc prototype accelerator at Rokkasho achieves its first deuteron beam.
2020: Commissioning of the JT-60SA tokamak is completed, and first plasma is achieved in October. The BA agreement is extended for a second time, to December 2025, to cover the operational phase of JT-60SA and continued R&D.
2023: JT-60SA achieves its first H-mode plasma, a critical operational regime for high-performance fusion devices. The IFERC supercomputer is upgraded to JFRS-2.

Current Status (as of 2026)

As of early 2026, the Broader Approach agreement is in its second extension phase, focusing on the exploitation of the completed facilities.

JT-60SA is in its operational phase. Following the achievement of the first plasma in 2020 and a successful initial experimental campaign, the device is undergoing planned upgrades and maintenance. The research program, jointly defined by Japanese and European scientists, is focused on integrated plasma scenario development for ITER and DEMO. Experiments are systematically exploring plasma confinement, stability, and power exhaust at parameters approaching those of a reactor.

IFMIF/EVEDA has successfully completed its primary validation mission for the LIPAc accelerator. The prototype demonstrated stable operation of a 125 mA continuous wave deuteron beam at the required energy of 9 MeV, meeting the project's technical objectives. The results provide the necessary confidence to proceed with the engineering design of a full-scale materials irradiation facility. The focus has shifted to the design of a follow-on project, DONES (DEMO-Oriented Neutron Source), which will be built in Spain and will leverage the technologies validated by EVEDA.

IFERC continues to support the fusion community. The JFRS-2 supercomputer provides significant computational resources for complex modeling, including turbulence simulations and integrated modeling of fusion plasmas. The DEMO design activities are ongoing, with joint working groups refining conceptual designs and coordinating R&D on critical technologies like tritium breeding blankets.

Notable Implementations

The Broader Approach is implemented through a close collaboration between designated institutions:

/programs/qst (National Institutes for Quantum Science and Technology, Japan): As the Japanese domestic agency, QST is responsible for hosting and operating the BA facilities in Naka and Rokkasho. It provides the infrastructure, a majority of the personnel, and leads the execution of the projects on the ground.
/programs/fusion-for-energy (F4E, Europe): As the Euratom domestic agency for ITER and the Broader Approach, F4E manages the European contribution. This primarily involves procuring high-tech components from European industries and laboratories and seconding European staff to the project sites in Japan. F4E oversees a portfolio of contracts with hundreds of companies and research centers across Europe.

The collaboration extends beyond these two main bodies to include a wide network of universities, research institutes, and industrial partners in both Japan and Europe who contribute to the research programs and supply components.

Open Challenges

Despite its successes, the Broader Approach faces several challenges moving forward:

JT-60SA Exploitation: Maximizing the scientific return from JT-60SA requires sustained funding for operations, data analysis, and a robust scientific program. Coordinating research priorities between the large and diverse European and Japanese fusion communities to effectively support ITER and DEMO is a continuous logistical and scientific challenge.
Transition to a Materials Irradiation Facility: The successful validation of accelerator technology by IFMIF/EVEDA is a major step, but the ultimate goal of qualifying materials requires the construction of a full-scale neutron source. Securing the international consensus and funding for the next step, such as the DONES project in Spain, and ensuring a smooth transfer of knowledge from the BA activities are critical.
DEMO Design Divergence: While IFERC coordinates DEMO design activities, Japan and Europe have distinct national DEMO design concepts (e.g., JA-DEMO and EU-DEMO). A key challenge is to harmonize R&D efforts and find synergies between these designs to avoid duplication and maximize the impact of joint research.
Future of the Collaboration: The current BA agreement is set to conclude in December 2025. Negotiating the future framework for the Japan-Europe collaboration post-2025 is a priority. This will involve defining the scope of future joint work on JT-60SA operation, DEMO R&D, and other strategic areas in a way that continues to provide mutual benefit.

Outlook

The credible 5-15 year trajectory for the Broder Approach and its successor activities is centered on exploiting the world-class facilities it has created.

In the near term (2026-2030), the primary focus will be on the full scientific exploitation of JT-60SA. The device is expected to conduct high-power, long-pulse experiments to pioneer steady-state operational scenarios and test advanced divertor concepts, providing crucial data for the design of ITER's later operational phases and for DEMO. The collaboration framework beyond 2025 will likely be renewed to reflect this operational focus.

Over the medium term (2030-2035), the knowledge and technology from IFMIF/EVEDA will be directly incorporated into the construction and commissioning of a dedicated fusion neutron source like DONES. This will initiate the multi-year irradiation campaigns necessary to develop a database for nuclear-grade structural materials, a prerequisite for licensing any fusion power plant. Concurrently, the DEMO design activities at IFERC will mature, moving from conceptual to engineering design phases, heavily informed by results from both ITER and JT-60SA.

By 2040, the legacy of the Broader Approach will be evident in the operational maturity of ITER, the advanced engineering designs for DEMO in both Europe and Japan, and the existence of a dedicated facility for testing fusion materials. The agreement has established a model for bilateral, large-scale scientific collaboration that has significantly de-risked and accelerated the global fusion development timeline.

References

The Broader Approach agreement between the European Atomic Energy Community and the Government of Japan for the joint implementation of the broader approach activities in the field of fusion energy research — Official Journal of the European Union (2007)
JT-60SA: A key step towards ITER and DEMO — Fusion for Energy
The Broader Approach to Fusion — National Institutes for Quantum Science and Technology (QST)
Status of the Broader Approach projects — Nuclear Fusion (2022)
First plasma in the JT-60SA tokamak — ITER Organization (2020)
Validation of the IFMIF LIPAc prototype accelerator — Nuclear Materials and Energy (2021)
Decision (EU) 2020/2153 on the extension of the Agreement between the European Atomic Energy Community and the Government of Japan for the Joint Implementation of the Broader Approach Activities — Official Journal of the European Union (2020)
The International Fusion Energy Research Centre (IFERC) — Broader Approach Activities