[en] The RA-6 is an open pool MTR type reactor with 500 Kw nominal power, using fuel elements enriched to 90 %. It was designed and constructed fully in Argentina and is owned and operated by the C.N.E.A. at the Bariloche Atomic Center. A design of the epithermal device was performed, analyzing different and relative sizes of the materials conforming the neutron filter to optimize the neutron spectrum and the absolute value of the epithermal flux at the beam port. This design was used also to make preliminary studies regarding the nuclear safety and solve potential licensing problems. A complete design of the internal filter was presented to the Regulatory Authority and after some feedback the filter was constructed and mounted. During this stage a very simple (without any geometry complexity) external port was used to test the free beam facility and to get a complete on phantom dosimetry. Using the previous results the new beam port was designed, built and mounted by november 1998. The final characterization of the facility was performed, obtaining a good agreement between calculated and measured values The irradiation room was designed and is being constructed to adequate the facility to irradiate patients. (author)

[en] The RA-10 is a new multipurpose research reactor that is under construction in Argentina. It is a 30 MW thermal power reactor and it is designed to achieve high performance neutrons production to fulfil the stakeholder’s requirements in compliance with stringent safety regulations. The principal objectives of the facility are to consolidate and increase the radioisotope production in order to cover future demands, to provide fuel and material testing irradiation facilities in order to support national technology development in this field, to offer new applications in the field of science and technology based on modern neutron techniques. The project is supported by the National Administration and is conducted by the National Atomic Energy Commission (CNEA). The construction stage was begun on 2016. Previously, the construction license and the environmental aptitude certificate were obtained, and a social perception study was performed. The first concrete was built on May 6 2017. The global advance of the project is 58%. The reactor is planned to be commissioned on 2022. From the feasibility study stage effort was focused on identified gaps related to management, reactor utilization, human resources development, stakeholder involvement and procurement. According to the chosen model for the project organization, responsibilities were assigned to in-house groups and external companies within the frame of a few main contracts and internal agreements. The project organization had to be adapted for this stage reinforcing capabilities related to coordination, integration and controlling. CNEA has updated the project management system with specific procedures, modifying the corresponding quality system for handling this stage. The contractor´s quality systems had to be reviewed and adapted. Specific schedules had to be integrated. The commitment with safety culture was reinforced by assuming that, beside the contractors’ participation, the responsibility for implementing the license relies on the operating organization. The main ongoing activities developed during this stage include the civil work construction, the industrial components manufacturing and mounting and the nuclear supplies and component provision, the development of the future operation team and the users´ involvement. Also, the future reactor exploitation is being addressed by an update of the Strategic Plan and the corresponding Business Case. The plant documentation elaboration and preoperational tests preparation are being developed. Regarding licensing, beside the upgrade of the Preliminary Safety Report and the commissioning preparation, the main objective is to assure and demonstrate that the licensee, and all safety and regulatory requirements, are correctly implemented. This paper describes the status of the project, considering the experience of the construction stage, for the different involved activities, with emphasis on their interactions and the application of control tools. (author)

[en] The RA-10 is a new multipurpose research reactor which has been decided to be built in Argentina in order to satisfy the increasing national and regional demands for radioisotopes. The RA-10 is a 30 MW thermal power open pool) facility with MTR (Material Testing Reactor) type fuel assemblies. A Surveillance Program is part of a more general Ageing Management Program and its objective is the assessment of the structural integrity of critical core materials components in order to ensure a safe and reliable long term operation. Neutron irradiation affects ductility, tensile and toughness properties of materials in general and might result in irradiation induced growth in Zirconium base structural materials. Ad-hoc surveillance programs have to be developed for research reactors considering the peculiarities of each design. in the present case, the most exposed critical components were firefly identified. Thereafter, the critical components were categorized in those that are replaceable or no replaceable along the expected life of the reactor: -The materials of interest. are Zircaloy-4, Zr-2.5 wt%Nb. The evaluation of the effects of irradiation is followed by periodically removing (2, 5, 10, 20, 30 and 40 years) capsules containing tensile, fracture toughness CT and small punch testing specimens representative of the different materials and thermomechanical conditions. Dosimeters are placed within the surveillance capsule and evaluated to determine the associated neutron fluence at the specific location within the vessel and time of extraction. Specimens will undergo post-irradiation testing in a hot cell facility to determine their mechanical properties (and dimensions). The obtained values will be compared with the original values and the predefined design limits to evaluate the operational margin of safety. In summary, the present paper describes the methodology of the implemented surveillance program, the test specimens, their locations and the tests to which they will be subjected. (author)

[en] Neutron radiography is a non-destructive test in which it is registered an image of the attenuation experienced by a collimated neutron beam while it passes through a sample. The image is generated by using a neutron-sensitive screen. The applications of this technique are wide, some of them include: services to industries, study of explosives, study of pieces belonging to cultural heritage and studies of the distribution of hydrogen. The actual neutron radiography facility is placed in the RA-6 reactor at the Centro Atomico Bariloche. Due to the reactor's nucleus change and the subsequent power raise, it has been necessary to redesign the facility. During the last year the pieces that constitute it had been designed and built. In April 2012 the facility has been mounted. The system employed is of on-line neutron radiographies. The maximum area of study is of 20 cm x 20 cm. The images obtained are registered by a CCD camera, whose maximum resolution is of 2776 x 2074 pixels and 65536 gray levels. In this work the initial steps towards characterization of the facility are presented, these include neutron fluxes and dose rates levels determinations. Also, in order to evaluate the functionality, images of several objects have been taken, as the one shown in Fig. 7. The results obtained reveal the good performance of the facility and its wide potential (author)

[en] A new multipurpose research reactor to replace RA-3 reactor has been decided to be built in Argentina to satisfy the increasing national and regional demands for radioisotopes. The project, supported by the National Administration, has started in 2010 and is planned to be operative in 2018. The expertise acquired in the country, in the design and licensing of nuclear reactors, encourage the National Atomic Energy Commission (CNEA) to face the challenge. INVAP S.E. is involved in the design and construction of the reactor facility and related installations, playing the role of main contractor. The RA-10 is a 30 MW thermal power reactor and is designed to achieve high performance neutrons production to fulfill the stakeholder's requirements in compliance with stringent safety regulations. The principal objectives of the facility are: to consolidate and increase the radioisotope production in order to cover future demands, to provide fuel and material testing irradiation facilities to support national technology development on this field, to offer new applications in the field of science and technology based on modern neutron techniques. The reactor is an open-pool facility with a compact core with MTR (Material Testing Reactor) low enriched uranium (LEU) fuel assemblies consisting of uranium silicide fuel plates, cladded in aluminum. Reactivity control is performed by hafnium plates. A heavy water reflector tank surrounds the core. It provides a high thermal neutron flux adequate to house irradiation facilities. A diverse and independent shutdown system is engineered through its drainage. The fundamental safety objective of the design is the radiological protection of the public, the personnel and the environment and consequently the design is based in three main principles: responsibility in safety management, defense-in-depth and safety features. Engineered Safety Features are provided which are capable of maintaining the reactor in a safe condition under all anticipated operational conditions and design basis event. (author)

[en] The reactor RA-6 NCT system was improved during the last year mainly in two aspects: the facility itself getting lower contamination factors and using better measurements techniques to obtain lower uncertainties in its characterization. In this job we show the different steps to get the source to be used in the treatment planning code representing the NCT facility. The first one was to compare the dosimetry in a water phantom between the calculation using the entire facility including core, filter and shields and a surface source at the end of the beam. The second one was to transform this particle by particle source in a distribution one regarding the minimum spatial, energy and angular resolution to get similar results. Finally we compare calculation and experimental values with and without the water phantom to adjust the distribution source. The results are discussed. (author)

[en] The RA-6 reactor at the Bariloche Atomic Centre was designed mainly as a teaching tool. During its almost 21 years, after the first criticality, it was used as a support for several graduate and post graduate careers at the Balseiro Institute, depending on the Argentine National Atomic Energy Commission and the Cuyo National University. Besides these tasks, a big work was done in research and development using the synergy produced by the close relationship between the students and researchers. Main characteristics of the reactor are described. An outline of use for teaching and training is given. Research activities resulting from appropriate personnel management and students' cooperation that allowed achieving different grades of development are described. (author)

[en] The RA-6 reactor, located at the Bariloche Atomic Centre, is owned and operated by the Argentinean National Atomic Energy Commission (CNEA) and was commissioned in October 1982. It is a 500 kW, MTR, open pool-type reactor with highly enriched fuel elements. The main goal of the present project is to upgrade the reactor power to 3 MW in order to improve current applications and to develop new ones. To achieve this objective, a new core with LEU fuel elements was developed. Based on previous experience in the certification of a similar fuel element originally designed for the OPAL reactor (Australia), the new design is based on low enriched (19.7%) uranium silicides, including burnable poisons. The proposed core configurations are focussed on installing in-core irradiation facilities as well as for maximizing the performance of the external beam tubes facilities. The reactor modifications include the primary cooling system, the secondary cooling system, the electrical system, the instrumentation system, the shielding of some external facilities, etc. Safety studies related to the project are being performed in order to obtain a new licence for the entire facility, not only because of the modifications but also to generate updated regulatory documents; including the safety analysis report, the code of practice, the operation manual, the maintenance manual, etc. The funds for the core conversion are being provided by the United States Department of Energy. (author)

[en] A hyperthermal beam has been developed at the RA-6 reactor Boron Neutron Capture Therapy (BNCT) facility in order to perform human clinical trials for the treatment of skin melanomas in extremities. Based on the previously developed epithermal beam, the objective was to modify it in order to improve its therapeutic gain for the treatment of skin melanomas up to 2 cm in depth. After finishing the beam set up and commissioning stage, a theoretical analysis of such beam performance has been completed, based on a clinical case of malignant melanoma in extremities. In spite of the complexity of the clinical case under review, results showed that only 4% of the tumour volume is under dosed in cases of mean blood ¹⁰B concentration values, even in the most unfavourable analysis. The overall results suggest that this BNCT facility is prepared to rigorously explore the clinical efficacy of the RA-6 beam and the BNCT treatment modality for peripheral melanomas. A special configuration was arranged for in vivo experiments with small animals like hamsters and mice. These experiments were successfully performed in order to analyze the potential of BNCT for the treatment of oral cancer in the hamster cheek pouch model and undifferentiated thyroid carcinoma. (author)

[en] In order to perform a beam-physical dosimetry characterization, fast neutron and gamma dose rates, and thermal neutron flux were measured along the central axis in a water-filled phantom in the RA-6 BNCT facility. Threshold activation detectors were also activated in a different approach to determine fast neutron dose. Comparison with MCNP4B calculation for the same geometry was made, in order to determine a surface source for Treatment Planning calculations. (author)