Nuclear Area

Reactores RA-6 y RA-8 de Argentina

The RA-8 Argentine Reactor's only mission was to test the fuel for the future CAREM Power Station.  RA-8 was designed and constructed by INVAP for the Argentine Nuclear Authority (CNEA) in Pilcaniyeu, Province of Río Negro, Argentina.  It was in operation from 1997 to 2001.  This kind of low power reactor is usually short-lived, since they go out of service once their mission is complete.  Though they are similar in design to open pool research reactors, their purpose is different: to test the quality of fuel elements and the core design in a physical scale model.

The RA-8 is an open pool, zero-power reactor.  It generates only 10 watts of thermal power, with a maximum of 100 in full operation.  With such low thermal emission, there is no need for a complex cooling system.  Natural convection of the pool water is enough to cool the core.  Fuel elements used by the RA-8 during its short life will activate the future CAREM station: low enriched uranium oxide in a zircaloy clad.

This material has a proportion of the U235 fissile isotope, which may be 1.8 to 3.4% of the total uranium inventory. CAREM control elements, silver, indium and cadmium plates intended to absorb neutron excess, were also tested in the RA-8.

The RA-6, inaugurated in 1982, was the first research reactor built by INVAP. Is is located in San Carlos de Bariloche, Rio Negro, on the premises of the Centro Atómico Bariloche (CAB) belonging to the Argentine Atomic Energy Commission (CNEA).  As an educational reactor, the RA-6 was part of the training of hundreds of Argentine and foreign professionals in the fields of physics, engineering, nuclear radiochemistry and materials science.   Besides, the reactor is used for research in different areas.  This open-pool research reactor, with a variable core arrangement, has a plain and versatile design and may function as a multipurpose unit.

For instance, in 2002 one of its bunkers was turned into a BNCT (Boron neutron capture therapy) facility, for the treatment of cancer.  The RA-6 is a multipurpose reactor (MPR), used for training and research, with a power output of 500 kW th, open pool, designed to use 20% enriched uranium fuel, and light water cooled. 

Toma exterior del RA-6 con nieveThe RA-6 is operated, maintained, reformed and repaired by its own operating personnel, which includes Nuclear Engineering and Physics students of the Balseiro Institute of Physics. The reactor building consists of two separate units, each constructed in compliance with seismic structural regulations which apply to the construction site.  One of the buildings houses the reactor while the other houses the ancillary systems, laboratories, classrooms and administrative facilities.

The starting point for RA6 was a basic design by the Reactor Design Department of CNEA. From that point on, INVAP was responsible for managing the construction of the reactor. INVAP designed and made key systems for the reactor, including all the components pertaining to the electronic control chains, both nuclear and conventional, the instrument bridge, the mechanics of the control rod movement, as well as the neutron and gamma detection systems. 

The RA-6 played a strategic role in boosting Argentina's exports in the nuclear area.  Foreign scientists that are now nuclear authorities in other countries - and therefore potential partners or buyers of Argentine technology - have been trained in its facilities. The installation, which was built according to schedule and on budget, was the first proof of INVAP's ability to design and implement complex projects.