The Maria reactor is Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

's second research nuclear reactor

Nuclear reactor

A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...

 and the only one still in use. It is located at Świerk-Otwock

Otwock

Otwock is a town in central Poland, some southeast of Warsaw, with 42,765 inhabitants . It is situated on the right bank of Vistula River below the mouth of Swider River. Otwock is home to a unique architectural style called Swidermajer....

, near Warsaw and named in honor of Maria Skłodowska-Curie. It is the only reactor of Polish design.

Maria is a multifunctional research tool, with a notable application in production of radioisotopes, research with utilization of neutron beams, neutron therapy, and neutron activation analysis

Neutron activation analysis

In chemistry, neutron activation analysis is a nuclear process used for determining the concentrations of elements in a vast amount of materials. NAA allows discrete sampling of elements as it disregards the chemical form of a sample, and focuses solely on its nucleus. The method is based on...

. It operates about 4000 hours annually, usually in blocks of 100 hours.

Technical description

The technical details of the reactor are given in the reference.

Maria is a pool type reactor with a power of 20 to 30 MW (thermal). Despite it being a pool reactor, it contains channels (aluminum tubes) individually connected to the primary coolant. The water pool provides cooling for elements (e.g., fuel elements) that are not otherwise cooled, and also acts as radiation shielding. Maria uses enriched uranium

Enriched uranium

Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...

 as fuel (80% enrichment in ²³⁵U till year 1999; 36% since). The fuel elements and channels are vertical but arranged conically. Water and beryllium

Beryllium

Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...

 blocks serve as the moderator (70% and 30% of the moderation, respectively). Elements of boron carbide

Boron carbide

Boron carbide is an extremely hard boron–carbon ceramic material used in tank armor, bulletproof vests, and numerous industrial applications...

 sheathed in aluminum are utilized for control, compensation, and safety. The use of beryllium blocks results in a comparatively large fuel lattice pitch, and consequently large volume for payload targets. There is also a graphite

Graphite

The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...

 reflector

Neutron reflector

A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, and tungsten carbide, or other materials...

 (aluminum sheathed). Maria supplies a neutron flux

Neutron flux

The neutron flux is a quantity used in reactor physics corresponding to the total length travelled by all neutrons per unit time and volume . The neutron fluence is defined as the neutron flux integrated over a certain time period....

 of 4x10¹⁴ n/cm²s (thermal neutrons) and 2x10¹⁴ n/cm²s (fast neutrons). There are six horizontal channels for controlled use of neutron beams. There is also a window of lead-containing glass through which the core can be viewed. The reactor is housed in a sealed containment

Containment building

A containment building, in its most common usage, is a steel or reinforced concrete structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radiation to a maximum pressure in the range of 60 to 200 psi...

.

History

Construction began on June 16, 1970 and the reactor was activated on December 18, 1974. With the shutdown of the Ewa reactor

Ewa reactor

The Ewa Reactor was Poland's first research nuclear reactor. Its name is derived from the first letters of the Polish words: Eksperymentalny , Wodny , and Atomowy as a reference to the Eve Curie....

 in 1995 it became Poland's only research nuclear reactor.

Production of medical radioisotopes

In February 2010, it was announced that Maria will start producing medical isotopes, to help ease the isotope shortages due to shutdowns of the Canadian NRU reactor

National Research Universal Reactor

The National Research Universal reactor, located in Chalk River, Ontario, is one of Canada’s national science facilities. It is a multipurpose science facility that serves three main roles....

 and the Dutch Petten nuclear reactor

Petten nuclear reactor

The Petten nuclear reactors are nuclear research reactors in Petten, Netherlands. There are two reactors on the premises of the Petten research centre: a high flux reactor and a low flux reactor....

.