The MARIA research reactor, Poland’s sole nuclear reactor, is of the channel-pool type and operates on uranium fuel enriched below 20% in 235U. The reactor utilizes water for moderation and a beryllium matrix that surrounds the fuel elements, with the core encased by a graphite reflector. With a capacity to reach a thermal power of 30 MW, MARIA's biological shield is comprised of water and heavy concrete, and features distinct cooling systems for the fuel channels and pool.

Within the reactor core are designated positions for target material irradiation. Additionally, MARIA is equipped with an apparatus for irradiation in the fast neutron spectrum, which serves purposes such as research into construction materials for fusion reactors, and has thermostatic probes that can withstand up to 1000°C internally.

Horizontal neutron beams emanate from the core to an experimental hall, facilitating material sample scanning, crystal structure analysis, excitation studies, and the mapping of impurity distributions. A dedicated beam, connected to the intra-core epithermal neutron converter, is earmarked for future radiobiological research and nuclear medicine applications.

In terms of radioisotope production, MARIA chiefly generates molybdenum-99, iodine-131, lutetium-177, phosphorus-32, samarium-153, cobalt-60, and holmium-166. These radioisotopes are the byproducts of nuclear transformations in target materials that are housed in specialized containers within the reactor core’s horizontal channels. Neutron bombardment instigates nuclear transformations, rendering most new nuclei unstable and resulting in decays that emit radiation useful for diagnostic and therapeutic applications. MARIA is one of the main global producers of molybdenum-99, a highly sought-after radioisotope in nuclear medicine, and meets about a third of the global demand for iodine-131, widely used for thyroid gland diagnosis and treatment. Moreover, MARIA is among the few facilities worldwide where microspheres containing holmium are irradiated to produce holmium-166 for palliative therapy in liver cancer treatment.

MARIA research reactor

The Regional Laboratory of Neutronography makes use of the  horizontal beams, and the physical hall is undergoing modernization eventually to accommodate cutting-edge equipment accessible to global scientists. The neutron diffractometers to be installed will facilitate the study of materials’ structures, including the arrangement of magnetic moments in crystal lattices. Upcoming installations include a neutron diffractometer in a flat cone configuration, a testing station with a diffractometer for internal stress analysis in technical structures, standard diffractometers for observing neutrons scattered at varying angles in the horizontal plane, and a neutron radiography station for observing water movement within porous systems during absorption or drying, which is invaluable for examining archaeological or historical artifacts.

The neutrons produced by MARIA are indispensable in the manufacturing of radiopharmaceuticals, and for contributions to nuclear medicine, scientific research, new materials studies, and industrial applications.