History of Materials Research: Six decades of operation of the IEA-R1 nuclear research reactor.


The IEA-R1, the first nuclear reactor in Brazil and the first research reactor in Latin America, completed 60 years of uninterrupted operation. This was commemorated with an international workshop on the use of research reactors. The event was held from November 28 to December 1 2017 in the city of São Paulo, in the auditorium of the Nuclear and Energy Research Institute (IPEN), located on the main campus of the University of São Paulo (USP). According to the organizers, about 300 people from different countries participated in the event.

IEA-R1 is well known in Brazil for producing radioactive isotopes that are used in medicine, industry and agriculture, partially meeting the national needs. Examples are Iodine-131, produced in IEA-R1 since 1959 and used in the diagnosis and treatment of thyroid cancer, and Samarium-153, used as a palliative tool to treat pain in bone metastases.

In addition to providing these elements to hospitals, industries and other entities, the IEA-R1 has been used, since the beginning, in research in several areas, including the Materials area. This research filed uses beams of free neutron (neutrons that were separated from the nuclei of the atoms), generated in the nucleus of the reactor through the nuclear fission process. The interaction of the neutrons with the samples provides unique information on the structure and composition of the materials.

According to Frederico Genezini and Rajendra Narain Saxena, IPEN researchers and current and former manager of the Research Reactor Center (CRPq), respectively, neutrons have a very specific feature of interacting with matter. It is possible, through scattering, to carry out studies of crystalline structures, and since the neutron has a magnetic moment, it is also used to study the magnetic properties of materials.

IEA-R1.
IEA-R1.

Located at IPEN, the reactor is formed by a 9-meter deep pool of deep blue waters. This color is originated by the so-called Cherenkov effect, in which charged particles (in this case, ions generated by nuclear fission) cross the medium (in this case, water) at a higher speed than light in that medium, emitting the flashy blue radiation. The pool water is contained by 1 to 3 meter thick walls constructed of very hard concrete. The bottom of the pool houses the reactor core, in which uranium is bombarded with neutrons, generating nuclear fission reactions. As a result, the nuclei of the uranium atoms are divided into two, while two or three neutrons and a large amount of energy are released (that very strong energy that holds the protons and neutrons together in the nucleus of the atom). While in the nuclear plants the released energy is harnessed, in the research reactors the most important product is the neutrons, the reason why the reactor components aim at preserving the free neutrons.

Water and concrete around the core perform important safety functions that prevent harmful levels of radiation from passing into the vicinity of the pool, where researchers, the team responsible for the reactor and the visitors circulate (about 2,000 people visit the IEA-R1 every year).

The process of producing uranium for IEA-R1 is completely carried out in Brazil. The ore is extracted and processed in the state of Bahia, enriched to a little less than 20% at the Navy Technological Center in Iperó (São Paulo state), and finally packed inside the “fuel elements”, which are then placed in the core of the reactor. Brazil belongs to the group of only 12 countries that can enrich uranium.

Neutrons to investigate matter

Around the pool – at the bottom, the IEA-R1 reactor has 12 experimental stations, in which neutron beams extracted from the reactor are available to be used in conjunction with several experimental techniques.

According to Genezini and Saxena, at present only three of the stations have equipment installed: the high-resolution neutron diffractometer, real-time neutron imaging systems, and the experimental system for boron neutron capture therapy (BNCT). However, other stations are available – on demand – for the installation of instruments. The first two facilities are very useful for studying materials, and have advantages over equivalent equipment that uses X-rays instead of neutrons. According to Genezini and Saxena, the diffractometer allows studying crystallographic structures of materials that an X-ray diffractometer cannot always observe, besides the study of magnetic structures.

“While X-rays interact with matter through electromagnetic forces, neutrons basically interact via nuclear forces,” explains Reynaldo Pugliesi, an IPEN researcher responsible for neutron imaging equipment, designed and built at IPEN and installed in one of the IEA-R1 stations. For example, a sample of 1 cm2 analyzed at this experimental station can receive about 8 million neutrons per second.

Neutron imaging provides, without destroying or damaging the samples, two or three dimension images (the latter called neutron tomography) of details that would otherwise be imperceptible to the human eye. In particular, hydrogen-rich materials (such as oil, water, adhesives and rubbers) are particularly well captured in neutron imaging, even when encapsulated in metals such as steel, aluminum and lead. In fact, the neutrons can penetrate several inches into the metals and reveal what’s inside them. Also in this regard, neutron imaging is complementary to X-ray imaging: while neutrons reveal light materials that are behind heavy materials (such as a crepe tape inside an aluminum frame), X-rays reveal heavy materials behind lightweight materials (such as the bones in the hand).

Neutron tomography: inspection of a restoration made in a ceramic vessel to check the degree of perfection of the work.
Neutron tomography: inspection of a restoration made in a ceramic vessel to check the degree of perfection of the work.

The IEA-R1 is open to the scientific and business community through collaborations with CRPq researchers. “In this model we have many examples of institutions and companies that have used the IEA-R1 neutron beams and other instruments in the CRPq laboratories for measurements,” says Genezini. According to him, other models are not possible because there are no technicians dedicated to each instrument. “However, this model has proven to be inefficient and we are investing in instrumentation and regulations to make neutron beam equipment more accessible to people outside the organization,” concludes the CRPq manager.

History

The origins of the IEA-R1 nuclear reactor date back to the mid-1950s, when the United States, under President Dwight Eisenhower, launched the “Atoms for Peace” program, which disseminated and encouraged worldwide the peaceful use of nuclear technology. In this context, Brazil and the United States signed agreements aimed at the discovery and research of uranium in Brazil and the development and use in Brazil of radioactive isotopes for agriculture and industry. For this, it was necessary to have a nuclear reactor in the national territory.

Thus, in August 1956, the Brazilian government decreed the creation of the Institute of Atomic Energy (IEA), which would later be called IPEN, to supervise the construction and operation of the IEA-R1. The construction was carried out by the US company The Babcock & Wilcox Company, accompanied by a Brazilian team led by the first director of the IEA-R1, the Brazilian nuclear physicist Marcelo Damy de Souza Santos, also the founder of the IEA. In August 1957, the construction of the reactor was completed and, on September 16 of that same year, the reactor reached the necessary conditions to start operating. The inauguration ceremony of the IEA-R1 was held on January 25, 1958, with the presence of President Juscelino Kubitschek and the State Governor of São Paulo Jânio Quadros.

With the IEA-R1, Brazil was able to develop national knowledge to produce nuclear fuel, neutron research instruments and radioisotopes that have been used in health, agriculture and in various industries. The reactor was also used to produce, through the neutron-induced transmutation technique, semiconductors for electronic components that were exported. In addition, it was used to train reactor operators and to conduct academic work. According to Genezini and Saxena, more than 250 doctoral theses and master’s dissertations were defended during this period in the areas of Nuclear Physics and Condensed Matter, and more than a thousand scientific articles were published in indexed journals.

In the near future…

Another chapter in the history of research reactors in Brazil is being written. The Brazilian Multipurpose Reactor (RMB), a more modern nuclear reactor with 30 MW of power (versus 5 MW of IEA-R1) is underway. In conjunction with its experimental stations, the RMB will be a national laboratory open to the community for research and for production of radioisotopes, installed on a 2 million m2 site in Iperó (SP).

According to José Augusto Perrotta, technical coordinator of RMB, the reactor is still in the design phase. The conceptual and basic projects have already been completed, and the detailed project is being executed. In addition, the IBAMA (Brazilian Institute of Environment and Renewable Natural Resources) license has been issued, as well as the site license of CNEN. However, the initial timeline was affected by problems related to financial resources. “The Ministry of Science, Technology, Innovations and Communications did not release the resources in 2017,” says Perrota. “The project continued with only the resources designated in 2014. Every year without resources is a year behind schedule!” he laments.

 

More info

Brazilian Multipurpose Reactor: a national laboratory of neutrons for the Materials research community.


Building of the reactor and labs.

At the end of September 2015, in the context of the XIV SBPMat Meeting, around 40 researchers of the Materials field participated in a symposium about the Brazilian Multipurpose Reactor (RMB), a project that has been developed by the Brazilian National Nuclear Energy Commission (CNEN) and that, when inaugurated in Iperó (SP), will add an important research tool to the current facilities that Brazil has.

As a matter of fact, the RMB will provide beams of neutrons that, when interacting with samples and with the mediation of several experimental techniques, will be able to provide unique information about the structure of the materials. For such, the RMB project envisions the construction of a series of laboratories with diffractometer equipment (of high resolution, of high intensity, Laue, of residual tension); small angle scattering; analysis of prompt gamma; triple-axis spectrometry and neutrongraphy, among other techniques. This research infrastructure must comprise a laboratory open to the scientific community and working day and night, more than 300 days a year: the Brazilian National Laboratory of Neutrons.

As indicated by its name, RMB will meet several goals. Besides providing beams of neutrons for scientific research, it will be used in irradiation tests of materials and fuels used in nuclear power plants for electricity generation and submarines propelled by nuclear reactors, for instance. The reactor will also have the important mission of producing radioisotopes and radioactive sources for health, industry, agriculture and environment, replacing imports and even generating exports.

Interview with the technical coordinator

To further explain the RMB project and, in particular, its applications in materials science and technology, we interviewed José Augusto Perrotta, technical coordinator of the RMB enterprise. Master in Nuclear Engineering by the Military Institute of Engineering (IME), and PhD in Nuclear Technology by the São Paulo University (USP), Perrotta works as technologist at CNEN since 1983.

SBPMat Newsletter:Briefly comment about all the possibilities that the future RMB will offer to the materials science and technology community. In what way the beams of neutrons can be used for research and development in this area?

Production and research nucleus.

José Perrotta: – RMB is an enterprise that has as its core part a nuclear multipurpose research reactor and several laboratories to perform research, services and products.

The reactor was conceived with a high flow of neutrons to:

i.        Produce radioisotopes in the quality and amount needed to Brazilian applications;

ii.        Have the ability to irradiate and test nuclear fuels used in the several applications and irradiation conditions within the Brazilian nuclear program;

iii.        Have the ability to irradiate materials with neutrons and check its performance under irradiation;

iv.        Have the possibility to irradiate samples to perform a chemical analysis via activation of neutrons;

v.        Extract beams of neutrons for research on materials structure in several application areas.

Regarding item (ii), the reactor is prepared to receive fuel samples and irradiation circuits that simulate the conditions of PWR reactors, that is, test fuels of the power reactors used or developed in the country.

Regarding item (iii), inside the reactor core there are two positions with high flow of neutrons for irradiations of materials. In these positions, samples can be placed in capsules with a controlled environment (temperature and medium of insertion of the sample). In these positions, samples of structural materials and samples of components of power reactors used in the country can be tested.

The reactor and the infrastructure of the reactor (pools, hot cells and transport shields) are designed to meet the two previous items (ii and iii).

A Post-Irradiation Analysis Laboratory is designed with hot cells and the entire infrastructure for mechanical, physical and microscopy analysis of the irradiated samples, both for the samples of irradiated fuels and for the structural materials.

Regarding item (iv), a laboratory of analysis by activation and radiochemistry is projected. The laboratory is connected to the reactor via pneumatic pipes that allow sending samples for irradiation in the reactor and bring them back to the laboratory for analysis. Several irradiation positions were defined in the reactor, varying the range of flow of neutrons in which the irradiations can be performed. The laboratory has hot cells to receive and handle the irradiated samples before their destination to the analysis equipment (radiochemistry or gamma spectrometry). The laboratory will be managed as a national laboratory, which will allow its use by the Brazilian scientific community.

Regarding item (v), the reactor is designed with a heavy water reflector tank that, mechanically, allows the extraction of beams of neutrons. These neutrons are thermal, and in order to obtain cold neutrons a small tank with deuterium at 19ºK (cold source) is designed. Thermal neutrons will be extracted in two positions and cold neutrons in two other. Each extraction tube may contain up to three neutrons guides. These guides will conduct the beam of neutrons for positions in a lobby of experiments at the building of the reactor, and in a building called neutron guides building. Scientific and technological equipment can be attached to the neutron guides for the analysis of the samples with the beam of neutrons. There is an additional thermal neutron extraction tube to make images with beam of neutrons (neutrongraphy). The experiments lobby in the reactor building and the guides building will form what we call “National Laboratory of Neutrons” (LNN).

SBPMat Newsletter: Will there be experimental stations for Materials Science and Technology, analogous to the Brazilian Synchrotron Light Laboratory (LNLS)? Which ones? Will they be open to the entire scientific community? Will they operate constantly while the reactor is working?

José Perrotta: – The neutrons lines, as mentioned, are five: three with thermal neutrons and two with cold neutrons. Four of the lines can have up to three guides. In these guides, the experimental instruments (or stations) will be placed.

The following stations might be available since the beginning of the operation of the National Laboratory of Neutrons

i.        Neutrons Guides Building.

  • For thermal neutrons: High Resolution Diffractometer; High Intensity Diffractometer; Laue Diffractometer; Residual Tension Diffractometer.
  • For cold neutrons: Small Angle Scattering; Prompt Gamma Analysis

ii.        Experiments Lobby in the Reactor Building.

  • Thermal Neutrons: Triple Axis Spectrometer; Neutrongraphy
The table shows the power of other research reactors worldwide. The Brazilian RMB will have a power of 30 MW. (Data provided by José Perrotta)

The RMB will bring to the country’s research community an important laboratory for utilization of neutrons beams. This laboratory, per its technical characteristics, is complementary to the Brazilian Synchrotron Light Laboratory (LNLS), which also has a large scale project, the Sirius. It is a proposal of the RMB enterprise that the National Laboratory of Neutrons is, like the LNLS, a national laboratory. This will facilitate the access of the Brazilian scientific society to the facility.

The functioning of the neutrons lines is related to the operation of the reactor. The reactor will operate 24 hours a day, in cycles of 25-28 days, in a way to achieve availability higher than 80% of the annual time (more than 300 days in full operation). The LNN can operate during all this time.

An important point is that the LNN will be operationally independent regarding the operation of the reactor, that is, the operation of the reactor offers the beam of neutrons and does not interfere in the operation of the LNN.

SBPMat Newsletter: From the point of view of materials science and technology, which would be the advantages of the future RMB regarding the other reactors currently existing in Brazil?

José Perrotta: – Brazil has four research nuclear reactors in operation. The oldest one, and also the one with higher power (5 MW), is the IEA-R1 reactor from the Institute for Nuclear and Energy Research (IPEN) in São Paulo, which was unveiled in 1957. Other two low power research reactors, the IPR-R1 reactor of the Center for Nuclear Technology Development (CDTN) in Belo Horizonte (100 kW) and the Argonauta reactor of the Institute for Nuclear Engineering (IEN) in Rio de Janeiro (500 W) were built in the 1960s. These three reactors, of North-American designs, were built inside the university campuses of USP, UFMG and UFRJ, respectively, and originated the main nuclear research institutes of the Brazilian National Nuclear Energy Commission (CNEN), which developed themselves in proportion of the size of the reactors and their applications. These reactors and the CNEN institutes growing around them were essential in the development and use of nuclear technology that we have in the country today, and in the formation of the associated human resources. The fourth research nuclear reactor, the IPEN/MB-01 at IPEN, is an installation of the critical unit type (100 W) and was built in the 1980s, already with national technology, aiming towards the autonomous development of technology for power nuclear reactors.

The RMB reactor´s power is 30 MW and has modern design and conception. The reactors existing today in the country do not have flow of neutrons to ensure commercial operation or adequate characteristics for a high level research. In addition to being a more modern installation, the flow of neutrons of the RMB is one order of magnitude higher than the IEA-R1, and has functions that are not met by this reactor today.  The other three reactors have really low flow of neutrons.

SBPMat Newsletter:Could you estimate when the RMB and its research laboratories would be launched?

The RMB enterprise can be carried out in a period of 6 to 7 years. In the current stage of development, this would occur in 2022, if the full resources for the project are made available. It is important to highlight that, besides the need for intensive financial resources for its execution, the enterprise requires environmental and nuclear licenses for its construction and operation, since it has nuclear and radioactive facilities. This implies additional times for its implementation.

Funders and partners in the development of the RMB

The execution of the RMB project occurs under the responsibility of the Brazilian National Nuclear Energy Commission (CNEN).

The enterprise is coordinated by the Research and Development Directory of CNEN and developed by its research institutes: Nuclear Energy Research Institute (IPEN), Nuclear Engineering Institute (IEN), Nuclear Technology Development Center (CDTN), Northeast Regional Center of Nuclear Sciences (CRCN-NE) and Radiological Protection and Dosimetry Institute (IRD).

Throughout the stages of development of the RMB, CNEN counts and will count on partnerships, as well as contracts of national and foreign companies. Some of the partners participating so far: Brazilian Navy and the São Paulo State government, in the concession of the land where the RMB will be placed; the Brazilian Navy Technology Center in São Paulo (CTMSP); the cooperation of CNEN with the National Atomic Energy Commission (CNEA) from Argentina, which develops in Argentina the research nuclear reactor RA-10, similar to RMB. Contracted companies: Argentine company INVAP, which designed the Australian OPAL research reactor, and Brazilian company Intertechne have developed the basic engineering design of the enterprise.

With an estimated cost of US$500 million, the RMB is sponsored by the Brazilian Federal Government through the Brazilian Ministry of Science, Technology and Innovation (MCTI).