Budapest Research Reactor

The Budapest Research Reactor is one of the leading research infrastructures in Hungary and in Central-Europe. The major scientific activity at BRR is using neutron beams for neutron scattering investigations. We have more than 50 years of tradition in this field. BRR is a VVR-type (water-cooled, water-moderated reactor) of Soviet design and construction: it went critical on March 25, 1959. Originally, the reactor power was 2 MW, but it was upgraded to 5 MW in 1967. A second full-scale reactor refurbishment started in 1986, fully designed and performed by Hungarian companies. The project was supported by the International Atomic Energy Agency (IAEA) and the European Union. The reconstruction was completed by the end of 1990, but due to the political changes in the country, the license for reactor start-up was issued only in 1992. The reactor is being operated by the Centre for Energy Research (CER – one of the research centres of the Hungarian Academy of Sciences). In 1992, a consortium, named Budapest Neutron Centre (BNC), was formed with the participation of the neutron-research related laboratories on the KFKI campus. 


                                     KFKI Campus (with the reactor building chimney in middle)

BRR is a tank type reactor, moderated and cooled by light water. The reactor core is surrounded by a solid beryllium reflector. The main technical data of the reactor are: thermal power 10 MW; mean power density: 39.7 kW/litre; approx. maximum thermal flux: 2.1 × 1014 n/cm2s, maximum cooling water outlet temperature: 60oC.

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The reactor cycle is about 10 effective days, which is followed by a short break for a weekend. The Budapest Research Reactor is known for its reliable operation. About a 160 operational days per year are foreseen for the next years. However, the timetable is flexible accommodating the various requirements of the instrument developments.

Core conversion

Until 2009 the reactor was fuelled with Russian type VVR-SM fuel with 36% uranium enrichment (HEU), which later - due to the program of the core conversion - was changed to 20% enriched VVR-M2 type fuel (LEU), following the commitment to join the Russian Research Reactor Fuel Return (RRRFR) program. The geometric and thermo-hydraulic parameters of the new type of fuel elements are identical, whilst their nuclear features are similar to the previously used VVR-M and -M2 HEU fuel elements. In this way the core conversion scenario included both HEU and LEU fuels with gradually decreasing number of HEU fuel assemblies. During the core conversion 4 cycles with mixed HEU-LEU cores took place (over 8 months). Utilisation of HEU fuel was finished in 2012 and since then only LEU fuel has been in use. Due to the core conversion, no more than a 10% loss in neutron flux occured.