Reactor Infrastructure Centre (RIC) is part of "Jožef Stefan" Institute (JSI). Main purpose of the centre is operation of TRIGA Mark II research reactor for the needs of JSI and other research groups.

Reactor TRIGA Mark II is designed for:

T raining in reactor operation and technology,
R esearch with neutrons and
I sotope production. It was built by
G eneral
A tomics, a well known US nuclear company.

Reactor TRIGA Mark II was built by Jožef Stefan Institute in 1966. The reactor was delivered by GA, the reactor tank and body were built by Slovenian companies. In 1991  it was reconstructed and equipped for pulse operation.

The reactor has accu50mulated  years of continuous operation without any failure of major equipment or any event violating safety standards.

Technical conditions of the reactor allow for at least 10 years more operation. It is planed that the reactor will operate at least until 2026.

RIC is in organizational sense an infrastructure centre established and financed by the Ministry of Higher Education, Science and Technology and managed by Jožef Stefan Institute, like several other centres responsible for operating and maintaining large research equipment (e.g. accelerators, etc).

RIC is, however, in regulatory sense, a nuclear installation operated by Jožef Stefan Institute. Its operation is regulated by several national and international nuclear laws, regulations   and standards.

Their enforcement is regularly controlled by national and international bodies:

Slovenian Nuclear Safety Administration
Health Inspectorate of the Republic of Slovenia
International Atomic Energy Agency

Reactor building, reactor site and its surroundings are subject to permanent and systematic radiation monitoring performed by IJS Radiation Protection Group. Results of the monitoring are reported to Slovenian Nuclear Safety Administration and published in  their annual report on nuclear and radiological safety.

In 35 years there has been no release of radioactivity into environment (in atmosphere or  in water) exceeding limiting values prescribed by the law.

The cornerstones of TRIGA reactor nuclear safety are:

inherently safe design
qualified, experienced and devoted personnel
operation and maintenance subject to IJS and internal QA.

All questions related to nuclear safety are treated in detail in Safety Analysis Report.

Reactor generates approximately 50 liters of low and intermediate radioactive waste per year. It is  stored in the central storage for low and intermediate level waste located at the location of the reactor  centre and operated by the Agency for Nuclear Waste (ARAO).

219 spent fuel elements accumulated in operation since 1966 have been shipped for final disposal to USA in 1999. Presently, there are no spent fuel elements (highly radioactive waste) on the location of  the Reactor Centre.


Our main achievements

The reactor has been playing important role in developing nuclear technology and safety culture in Slovenia. It is  one of a few centres of modern technology in the country. Its international cooperation and reputation are important for promotion of Jožef Stefan Institute, Slovenian science and Slovenia in the world.

Practical benefits can be divided into three categories like the purpose of the reactor: training, research and isotope production.

Isotope production


  • practically all nuclear professionals in Slovenia started their career or attended practical training courses at TRIGA reactor (including all professors of nuclear engineering and reactor physics at Ljubljana and Maribor University, as well as directors and key personnel of NPP Krsko, Slovenian Nuclear Safety Administration and Agency for Radioactive Waste) .
  • all NPP Krsko reactor operators and other technical staff pass training courses on TRIGA reactor.
  • the reactor is used in regular laboratory exercises for graduate and post graduate students of physics and nuclear engineering at Faculty of Mathematics and Physics, Ljubljana University.
  • On-the-job training for IAEA trainees from developing counties (in average 2 per year) is important for promotion of IJS and Slovenian science.
  • Reactor has been used in several international training courses reactor is open to the visitors, more than 500 per year, mainly schools.


  • reactor has been used in research work published in approx. 300 scientific papers and more than 600 published conference reports.
  • more than 20 Ph. D. research works, more than 30 M. Sc. degree works and more than 100 Diploma works have been performed using the reactor.

Isotope production

  • total number of patients treated with radio-isotopes produced in the reactor is more than 50.000 (mainly radioactive technetium).
  • 10-20 industrial sealed sources per year (mainly cobalt), in total several hundred.
  • several special radioactive sources (e.g. radioactive sodium in soluble compound for turbine testing in Krsko NPP).

Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Phone: (01) 477 39 00, Fax: (01) 251 93 85