Thermal-hydraulic and neutronic experimental research in the TRIGA reactor of Brazil

A 100 kW TRIGA Mark I research reactor has been functioning since 1960 at the Nuclear Technology Development Center (CDTN), Belo Horizonte, Brazil. The reactor was installed for research, manpower training and production of radioisotopes to be used in industry, agriculture and medical treatment. The IPR-R1 TRIGA is a pool type reactor cooled by natural circulation of light water and an open surface. TRIGA reactors, developed by General Atomics (GA), are the most widely used research reactors in the world and they are characterized by inherent safety. The IPR-R1 was designed to operate at 30 kW steady-state power and 100 kW power for limited periods, namely four hours a day, two days a week. The reactor could not meet the increasing demand for operation with natural circulation alone. The forced cooling system was built in the 70s and the power was upgraded to 100 kW. Recently the core configuration and instrumentation were upgraded again to 250 kW at steady state. This paper describes some results of experiments that have been carried out in the IPR-R1 reactor in recent years with the aim of evaluating the behavior of some thermal-hydraulic and neutronic operational parameters. The research project meets the recommendations of the IAEA for safety, modernization and development of strategic plan for research reactors utilization. This work is in line with the strategic objectives of Brazil, which aims to design and construct the Brazilian Multipurpose research Reactor (RMB).