MYRRHA

MYRRHA
Name	MYRRHA
Location	Mol, Belgium
Status	Project
Reactor type	Accelerator-driven system
Fuel	Mixed oxide (MOX), Uranium, Thorium (research variants)
Coolant	Lead-Bismuth Eutectic
Electrical capacity	Research-scale (no dedicated grid output)
Owner	Belgian Nuclear Research Centre (SCK CEN)
Commissioning	Proposed 2028–2032 (subject to change)

MYRRHA

MYRRHA is a Belgian-led experimental nuclear system developed as an accelerator-driven subcritical reactor and multipurpose research facility. It is intended to combine a high-power proton accelerator, a spallation target, and a subcritical lead-bismuth cooled core to support research into nuclear transmutation, radioisotope production, and materials testing relevant to ITER, European Commission, and international nuclear programs. The project is coordinated by the Belgian Nuclear Research Centre and involves collaborations with national laboratories, universities, and industrial partners across Europe, United States, and Japan.

Overview

MYRRHA is conceived as a flexible research infrastructure integrating technologies from accelerator physics, reactor engineering, and nuclear fuel cycle studies. The central concept pairs a superconducting proton accelerator similar in lineage to projects like CERN accelerators and the European Spallation Source with a spallation target and a subcritical core concept rooted in studies from Los Alamos National Laboratory and the Oak Ridge National Laboratory. The facility is positioned to serve communities active in ITER materials testing, radiopharmaceutical companies like Siemens Healthineers and institutes such as Paul Scherrer Institute and Institut Laue–Langevin.

Design and technical specifications

The design couples a ~600 MeV to 1 GeV continuous-wave proton accelerator to a liquid metal spallation target and a fast-spectrum core cooled by lead-bismuth eutectic (LBE), drawing on coolant experience from Russian Navy submarine reactors and experimental reactors like BOR-60 and Phénix. The accelerator employs superconducting radio-frequency cavities similar to those used at DESY and FERMILAB and includes an injector lineage related to projects at GANIL and TRIUMF. The spallation target and proton beamline design reference technologies developed at PSI and RAL for neutron sources; the target interacts with a subcritical core concept influenced by proposals from CEA and the European Commission ADTF studies. Fuel options include mixed oxide (MOX) formulations with plutonium or enriched uranium, and proposed thorium-bearing lattices investigated by teams from INEEL and KTH Royal Institute of Technology.

Key technical parameters under development include proton energy, beam current, subcritical multiplication factor (keff safety margins used in IAEA guidance), thermal-hydraulic behavior of LBE informed by research at CNRS and TU Delft, and materials compatibility drawing on irradiation data from programs at SCK CEN and Karlsruhe Institute of Technology. Control and safety systems leverage digital instrumentation and control approaches developed for reactors such as EPR and research reactors like BR2.

Research and applications

MYRRHA is proposed to support transmutation of high-level radioactive waste, neutron irradiation for structural materials relevant to ITER and fusion blanket research, and production of medical isotopes used in nuclear medicine practiced at centers like Mayo Clinic and Memorial Sloan Kettering Cancer Center. The facility would enable experiments in fuel cycle research explored by institutions including OECD Nuclear Energy Agency member laboratories, enabling collaboration with European Organization for Nuclear Research (CERN) and pan-European consortia that include CEA and SCK CEN. Applied research domains include neutronics modeling using codes from OECD-NEA benchmarks, corrosion testing akin to studies at Imperial College London and Politecnico di Milano, and accelerator reliability research drawing on experience from LHC operations.

MYRRHA is also promoted as a production route for isotopes such as Actinium-225 and Lutetium-177, complementing production at cyclotron centers like National Cancer Institute facilities and radiochemistry programs at Ghent University.

Project history and timeline

The concept evolved from studies at SCK CEN in the 1990s and was formalized in European frameworks including projects under the European Commission Framework Programmes and collaborations with Euratom. Early design options considered sodium-cooled accelerator-driven systems examined by CEA and proposals from ENEA. MYRRHA milestones include preliminary design reviews with partners from European Spallation Source and industrial memoranda involving vendors from Areva (now Framatome) and suppliers who have worked on ITER components. National and international review panels, including experts from IAEA and OECD-NEA, have assessed safety, proliferation, and technical feasibility. Procurement, construction planning, and licensing engage Belgian authorities and stakeholders analogous to processes followed for reactors like Doel Nuclear Power Station and Tihange Nuclear Power Station.

Planned phases include a prototyping accelerator segment, installation of the main linac, commissioning of the spallation target, and progressive loading to full subcritical operation. Timelines have shifted in response to funding rounds, partner commitments, and lessons from large infrastructure projects such as ITER and European XFEL.

Safety, regulation, and environmental impact

Regulatory oversight follows Belgian nuclear regulatory frameworks comparable to licensing regimes applied at BR2 and coordinated with international standards from IAEA. Safety analyses address subcritical operation characteristics, decay heat removal in LBE circuits, and radiological protection for workers and the public with methodologies similar to those applied in assessments for EPR and research reactors evaluated by FANC (Federal Agency for Nuclear Control). Environmental impact studies consider potential releases, waste management pathways aligned with European Commission waste directives, and strategies for long-lived waste transmutation discussed within OECD-NEA forums. Public engagement and stakeholder consultation processes mirror approaches used in siting and permitting for large facilities like European Spallation Source and major research campuses.

Category:Research reactors Category:Belgium