Part 3
Projects & Landmarks
Energy / Landmark


Jules Horowitz Reactor

A high-flux facility for nuclear fuel and material performance, and for radioisotopes production


The Jules Horowitz Reactor (JHR) is a reference international user facility to observe and understand material and fuel behaviour in extreme nuclear environment with irradiation loops reproducing the operational condition of the different power reactor technologies. Its primary uses will be research into the performance of nuclear fuel at existing reactors, testing of materials used in reactors, testing designs for fuel for future reactors and the production of radioisotopes used in medicine.

The site preparation for the project began at the Cadarache Research Centre in 2007. The first concrete step for the reactor’s foundations was poured in 2009, and the central containment structure was completed with the addition of a 105-tonne dome in late 2013. JHR will be built and managed in the framework of an international cooperation between several organizations bound by a Consortium Agreement signed on March 2007 by partners from 9 countries. JHR is expected to be in operation in 2022.


The JHR is an experimental reactor facility. It is not intended to generate electrical power, but to provide scientific data concerning nuclear fuel and material behaviour under exposure to very high stresses – high neutron fluxes. The nuclear unit is composed of only one civil engineering structure supporting two zones with different containments: the Reactor Building (RB) and the Nuclear Auxiliary Building (NAB). The objective of this single structure is to contain all the radioactive materials in one place. The reactor is a pool type reactor with a maximum power output of approximately 100 megawatts. This power is dissipated via the primary and the secondary circuit to the external cold source during irradiation; the core, the primary circuit and experimental rigs, are completely enclosed in the RB. The Fission Product Laboratory will be settled in this area to be connected to several fuel loops either for low activity gas measurements (HTR) or high activity gas measurements (LWR rod plenum) or water measurements (LWR coolant) with gaseous chromatography and mass spectrometry.

The reactor pool is connected to several storage pool and hot cells located in the NAB through a water block. The experimental process will make use of two hot cells to manage experimental devices before and after the irradiation. Safety experiments are an important objective for JHR and require an alpha cell to manage devices with failed experimental fuel. A fourth hot cell will be dedicated to the transit of radioisotope for medical application and to the dry evacuation of used fuel. Three storage pools are dedicated respectively to spent fuel, experimental devices and mechanical components management. The reactor’s versatile modular design allows it to accommodate up to 20 simultaneous experiments. Its instrumentation allows previously unavailable real-time analysis to be performed.


JHR has a planned lifespan of around 50 years, and is designed to be adaptable for a variety of research uses by nuclear utilities, nuclear steam system suppliers, nuclear fuel manufacturers, research organisations and safety authorities. JHR will represent in Europe a unique experimental facility accessible to industry, research institutes, nuclear regulatory authorities and their technical supports.

JHR will be a key RI for the nuclear international community extending performances and assessing safety for nuclear power plants in doing so also strengthening technology credibility and public acceptance. In addition, it will be effective in training new generations of scientist and engineers in the strategic field of nuclear energy also guaranteeing the high level of expertise needed in the staff of power plants in all steps of their lifecycle, including operation and decommission. JHR will also ensure the production of radioelements for nuclear medicine and for non-nuclear industry.

legal status
political support
lead country
prospective member countries
The full list of research institutions involved must be found in the website of the RI
Roadmap Entry
Preparation Phase
Implementation/Construction Phase
Operation Start
estimated costs
capital value
1.800 M€
200 M€
100 M€
1.500 M€
Not Available

Cadarache Research Centre - CEA
Cadarache, France