RA-3 and RA-6. Argentine radioisotope research and production reactors

Argentina currently has two reactors for research and production of radioisotopes: the RA-3 at the Ezeiza Atomic Centre, and the RA-6 at the Bariloche Atomic Centre.

Although they are essentially radioisotope producers, they are also used in other applications such as semiconductor production, nuclear fuel testing, gem irradiation to increase their commercial value, neutron radiography, irradiation for industry, mining, environment, agriculture and hydrology, scientific research and technological development, analysis by activation or neutron diffraction system.


Inaugurated in 1967, it is the largest producer of radioisotopes in Argentina. It is an open tank reactor designed and built entirely by the National Atomic Energy Commission (CNEA) with an initial power of 0.5 MW. It was later increased to 5 MW and doubled in 2003 (to 10 MW) in order to meet national and international demand.

The RA-3 operates continuously four days a week to cover the demand for radioisotopes for medical, industrial and agricultural use. Molybdenum-99 is the radioisotope produced in this reactor in the largest quantities. It decays to technetium-99m which is used in most nuclear medicine studies throughout the world for imaging of various organs such as the heart, brain, lungs, liver, spleen, kidney, gall bladder and bone marrow.

The main activity of the RA-3 is the manufacture of radioisotopes for medical diagnosis and treatment. In addition to molybdenum-99, the facility produces iodine-131, chromium-51, phosphorus-32 and lutetium-177. These products are incorporated into various drugs that are used to detect cardiac, gastrointestinal, respiratory and oncological conditions, among others.

In addition, the RA-3 has been used throughout its more than 50 years of operation in activities such as the qualification of nuclear fuels, the study of materials, the irradiation of samples for neutron activation analysis, tests of the BNCT technique (Boron Neutron Capture Therapy, an experimental phase therapy against cancer), rock thermochronology studies for the oil industry or the training of qualified personnel to operate other nuclear facilities.


The RA-6, also designed and built entirely in Argentina, was inaugurated in 1982 by the National Atomic Energy Commission (CNEA) as a result of the international initiative to reduce enriched uranium in research reactors.

Since then, a series of structural modifications have been made, so that the new reactor, whose core currently operates with low-enriched uranium, has been operational since 2009.

The RA-6 was originally intended as a training tool for nuclear engineering students at the Balseiro Institute. However, its applications have expanded with the extension of its training function to students from other careers, its use for research and development in reactor physics and nuclear engineering, neutron activation analysis, neutron radiography, instrumentation and control tests, and materials irradiation, among others.

In 2016, the RA-6 joined the "Internet Reactor Laboratory" initiative proposed by the International Atomic Energy Agency (IAEA). This new web-based teaching and training platform allows students from Latin American universities that do not have reactors of this type to attend classes in reactor physics and participate in virtual experiences.

In summary, the main lines of work of this reactor are:

  • Teaching and Training: its teaching staff and infrastructure have turned the RA-6 into an emblematic academic facility in the country that not only provides teaching and training services to students of Nuclear Engineering at the Balseriro Institute but also to other institutions in Argentina and around the world.
  • Neutron Activation Analysis Laboratory: applications of nuclear techniques in environmental studies are developed.
  • Neutrography: the neutrons from the RA-6 are used to generate images of the interior of various objects, which cannot be visualised by X-ray radiography. This technique is used in various fields such as hydrogen storage technology, the manufacture of industrial devices and the study of the origin of fossils and archaeological artefacts.
  • BNCT or Boron Neutron Capture Therapy for the treatment of oncological diseases: the first application was made in October 2003 and since then significant progress has been made towards clinical implementation.
  • Instantaneous Gamma Neutron Activation Analysis: this technique is used to determine the chemical elements present in small samples from the gamma radiation they emit instantaneously while activated by a neutron beam from the reactor.
  • Neutron diffraction: neutrons from the RA-6 are used to measure crystalline textures and analyse residual stresses in various materials, obtaining information at the atomic level. It is used to study the quality and strength of parts in the nuclear, automotive and aerospace industries.
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