physics

Maria reactor

Maria reactor is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Maria reactor rather than just read about it. In short: The Maria reactor is Poland's second nuclear research reactor, commissioned in December 1974, and the only one still in use as of 2026. The first was the Ewa reactor (EWA), which was commissioned in June 1958 and dismantled by 2002.

Key takeaways

Maria reactor belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Maria reactor to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Maria reactor from memory before moving on to harder problems.

Reference excerpt

The Maria reactor is Poland's second nuclear research reactor, commissioned in December 1974, and the only one still in use as of 2026. The first was the Ewa reactor (EWA), which was commissioned in June 1958 and dismantled by 2002. It is run by the National Centre for Nuclear Research (NCBJ) at Świerk-Otwock, is located near Warsaw and is named in honour of Maria Skłodowska-Curie. It is the only reactor of Polish design. Research done with Maria includes the production of radioisotopes, research using neutron beams, neutron therapy, and neutron activation analysis. It operates for about 4,000 hours annually, usually in blocks of 100 hours.

Technical description The technical details of the reactor are given in the references. Maria is a pool-type reactor with a power of 30 MW (thermal). Despite 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 as fuel (80% enrichment in 235U till 1999, and 36% since). The fuel elements and channels are vertical but arranged conically. Water and beryllium blocks serve as the moderator (70% and 30% of the moderation, respectively). Elements of boron carbide sheathed in aluminum are utilized for control, compensation, and safety. The use of beryllium blocks permits a comparatively large fuel lattice pitch, and consequently large volume for payload targets. There is also a graphite reflector (aluminum sheathed). Maria supplies a neutron flux of 4 × 1014 n/cm2s (thermal neutrons) and 2 × 1014 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. Following preparation which started in 2004, Maria was converted to use low-enriched uranium (LEU) fuel by 2012.

History Construction began on 16 June 1970, and the reactor was activated on 18 December 1974. With the shutdown of the Ewa reactor in 1995 it became Poland's only research nuclear reactor. In 2015, Maria was relicensed for an additional ten years of operation, until 2025. On 1 April 2025, the Maria reactor was temporarily shut down due to the licence ending and was not expected to resume operations before the renewal of its licence (expected no earlier than 8 May 2025).

Production of medical radioisotopes In February 2010, it was announced that Maria would start producing medical isotopes in cooperation with Covidien, to help ease the isotope shortages due to shutdowns of the Canadian NRU reactor and the Dutch Petten nuclear reactor.

See also Anna reactor List of nuclear reactors

References

External links https://www.ncbj.gov.pl/en/maria-reactor

Illustrations

Worked examples

Example 1 — a first encounter with Maria reactor

Start with the simplest possible case. Write down what Maria reactor claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Maria reactor before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Maria reactor ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Maria reactor

In research: Maria reactor appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Maria reactor in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Maria reactor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Marie Curie, Neutron facilities, Nuclear research institutes, so understanding it makes those chapters shorter.
In everyday life: Look for Maria reactor outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Maria reactor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Maria reactor means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Maria reactor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Maria reactor in simple terms?

Why does Maria reactor matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Maria reactor?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Maria reactor.