50 years ago, exactly on 18 December 1974 at 0.17 a.m., the MARIA reactor was activated for the first time. It is a reactor "made in Poland" - it was built exclusively with the efforts of Polish specialists. MARIA is still in operation today and is currently the only operational nuclear reactor in Poland. MARIA is used to irradiate isotopes essential for saving human life and to produce new materials for various sectors of the industry. Physical research is carried out here and personnel are trained for the nuclear and radiological protection industries.

"On 17-18 December, the first critical experiment was conducted at the MARIA reactor. This experiment initiated the physical operation of the reactor. After the introduction of 6 fuel sections containing highly enriched uranium into the reactor core, a self-sustaining fission chain reaction was achieved and a steady-state level of neutron flux in the reactor was recorded. A novelty, in comparison to the previously carried out critical experiments on the EWA, ANNA, MARYLA and AGATA reactors (author's note: which were also built in Świerk), was the use of a digital machine for uranium fuel loading control, working in the ‘on-line’ system and coupled to the reactor sensors with the use of CAMAC-type equipment".

The construction of MARIA was modelled on the Soviet MR reactor. The idea based on the above-mentioned device was expanded to include the addition of horizontal and vertical channels, which greatly enriched the research and production capabilities of the new reactor. Nuclear materials: fuel, beryllium, graphite and aluminium alloy pipes and plates were purchased in the USSR, but the vast majority of the structures, systems and systems were made by Polish plants and factories and by IBJ (now NCBJ) employees. Fifteen companies mainly from Warsaw and Upper Silesia worked on the construction, employing a total of around 2,000 people, a third of whom were employees of the Nuclear Research Institute in Świerk.

Today, MARIA is a major global producer of iodine-131 used in the diagnosis and treatment of thyroid diseases. The reactor's operation covers 100 per cent of Poland's demand for this substance. MARIA also meets about 10-20 per cent of global demand for molybdenum-99, which is used in cancer diagnosis and therapy. One week of its operation helps 100,000 patients worldwide!

MARIA produces, among others, molybdenum-99, iodine-131, lutetium-177, phosphorus-32, samarium-153, cobalt-60 and holmium-166. These are radioisotopes used in cancer diagnostics and therapy, which form the basis of preparations exported under the POLATOM brand to more than 80 countries worldwide.

The reactor has an operating licence valid until 31.03.2025.

In 2023, MARIA was included in the Nuclear Research Reactor Modernisation Programme (Resolution of the Council of Ministers No. 108/2023 of 20 June 2023), the aim of which is to extend the period of its safe operation, at least until 2050.

On 12 December this year, after a long wait, the National Centre for Nuclear Research received a positive decision on the allocation of funding for the maintenance costs of the scientific and research apparatus/research station (SPUB) titled. ‘MARIA nuclear reactor with technical infrastructure and safety measures’.

The allocated funds are predominantly intended to cover the cost of purchasing nuclear fuel. This decision allows us to look somewhat more optimistically at the financial situation of the reactor and NCBJ in the coming year.

1. The first activation of the reactor in the presence of government authorities took place in July 1974, this was a so-called technological start-up - a media event
2. Ciekawostka** The critical experiment (first activation) started on 17 December 1974 and ended on 18 December 1974, at 0:17.

The quote originates from Rezonans, pismo Instytutu Badań Jądrowych nr 12 (59) grudzień 1974.