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.


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.


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.


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People from our community: interview with Angelo Fernando Padilha.

Prof. Angelo Fernando Padilha (USP).
Prof. Angelo Fernando Padilha (USP).

Angelo Fernando Padilha was born on August 30, 1951 in Novo Horizonte, a small city in the state of São Paulo, Brazil. He attended primary school and the first years of high school in his native city, and when he was 16 years old he moved to São Carlos, some 170 km from Novo Horizonte, to enroll in a “scientific course” that covered the last three years of secondary education and that provided the student a more in depth education than the “classical course” in Mathematics, Physics, Chemistry and Biology.

In 1970, he enrolled in the just created undergraduate course in Materials Engineering at the Federal University of São Carlos (UFSCar). He graduated in 1974. The following year he participated in a specialization in Nuclear Science and Technology of the Brazilian National Nuclear Energy Commission (CNEN), offered at the Institute of Atomic Energy (IEA), currently the Nuclear and Energy Research Institute (IPEN), in the city of Sao Paulo. That same year he began working at IEA with research and development of materials for nuclear reactors. Also in 1975, Padilha began his master’s degree in Metallurgical Engineering at the University of São Paulo (USP), which he concluded in 1977 with the approval of his dissertation on recovery and recrystallization in aluminum alloy.

In 1978, still with the IEA, he began his PhD in Mechanical Engineering at the Universität Karlsruhe, now Karlsruher Institut für Technologie (KIT), Germany, obtaining a Doktor-Ingenieur diploma in 1981 after defending his thesis on precipitation in stainless steel, used in the fuel element of the German fast breeder reactor SNR-300. The following year, at the Max Planck Institut für Metallforschung in Stuttgart, Germany, Padilha participated in a three-month specialization in Materials Science in which he studied phase diagrams involving refractory metals.

From 1984 to 1986, in addition to his research activities at IPEN, he was professor in the undergraduate course in Metallurgical Engineering at the Mackenzie Presbyterian University, also in São Paulo.

From 1987 to 1988, he was a postdoctoral researcher at Ruhr Universität Bochum (RUB) in Germany.

In 1988, after 13 years working at IPEN, Angelo Padilha became a lecturer at the Department of Metallurgical and Materials Engineering at the Polytechnic School of the University of São Paulo (EPUSP). At the Polytechnic he became Adjunct Professor in 1989, and in 1993 he was approved as a Full Professor.

In 1993, he returned to RUB, Germany, for a specialization in duplex stainless steels. In 1998, he held a second postdoctoral fellowship at the University of Wales Swansea, now Swansea University, UK.

From July 2011 to November 2015, USP granted him a leave of absence to hold management positions in agencies linked to the Ministry of Science, Technology and Innovation (MCTI), currently Science, Technology, Innovations and Communications (MCTIC). During this period he was president of CNEN and of its deliberative commission, president of the National Fusion Network – RNF (created in 2006 to coordinate and expand nuclear fusion research in Brazil) and president of the board of directors of two nuclear companies linked to the MCTI , Nuclebras Heavy Equipment (NUCLEP) and Nuclear Industries of Brazil (INB). He was also a member of the sector funds coordination committee and from 2012 to 2014 he was a member of the technical-scientific council of the Brazilian Center for Research on Physics (CBPF).

He is the author of more than 100 papers published in indexed scientific journals and about twenty books and book chapters, such as the well-known in Brazil textbook “Materiais de Engenharia.” His academic work has approximately 2,800 citations, according to Google Scholar. He has supervised 25 master’s dissertations and 24 doctoral theses.

Throughout his professional career, Padilha received several awards from the Presidency of the Republic, the Brazilian Navy and the Brazilian Association of Metallurgy and Materials (ABM), among other entities.

Currently, Angelo Padilha is a full professor at EPUSP where he teaches undergraduate and graduate courses and carries out research on metals. He has been a full member of the Academy of Sciences of the State of São Paulo since 2012 and a senior level CNPq productivity grant holder (level awarded to active scientists in research and teaching of human resources who have been 1 A or B level for a minimum of 15 years). His h index is 27, according to Google Scholar.

Our interview with the researcher.

SBPMat Bulletin: Tell us what led you to study materials engineering in the first group of Materials Engineering in Latin America (UFSCar, 1970-1974) and then become a researcher in the field.

Angelo F. Padilha: I had already decided to be an engineer while in high school, but I was not sure about which engineering modality I would choose. After completing high school in my hometown (Novo Horizonte, SP), I went to São Carlos to begin the scientific course. São Carlos was fundamental for my academic background. The city offered everything a 16-year-old boy could wish for! In the student environment there was plenty of culture, debate and rebelliousness. I’m talking about the beginning of 1967. The worst period of the military regime that had started in 1964 was yet to come.

My aunt told me about the creation of a materials engineering course in São Carlos after reading an article or an interview by Professor Sérgio Mascarenhas in the city newspaper, which made an impression. It was the first time I had heard of this Engineering modality. The entrance examination aroused my curiosity as it was very different from the exams of that time. I did very well and later I enrolled. The first group of materials engineering at UFSCar consisted of 50 students: 2 girls and 48 boys. The university had been installed on a farm of more than 200 acres, not far from the city, and the initial facilities were adapted. It was a calm and warm environment. Today, I can better evaluate what that meant and I am convinced that the course as a whole was excellent. The course offered us a consistent and modern scientific basis. The experimental classes were of the highest quality I know of for an engineering course. Thanks to the scientific and technological base acquired during my five years at UFSCar, I was able to take full advantage of the master’s degree in metallurgical engineering at the Polytechnic School and then the PhD at the Faculty of Mechanical Engineering at the University of Karlsruhe. Many students in our class carried out postgraduate studies at top universities in Brazil and abroad.

SBPMat Bulletin: From your perspective, what are your main contributions to the materials field? Please give us a brief description of the contributions you believe had the greatest or most outstanding impacts considering all aspects of your scientific activity.

Angelo F. Padilha: The materials area did a lot more for me than I did for it. I have never worked on the frontier of knowledge, nor have I sought scientific niches. I use modern scientific concepts and advanced experimental techniques to study, understand and perfect traditional and widely used materials such as steels and aluminum alloys. For example, my most read and cited paper (in co-authorship with Paulo Rangel Rios) is a review paper published in 2002, which discusses the microstructure of austenitic stainless steels; a material discovered in 1911 which is still widely used.

I consider writing technical books in Portuguese as a gratifying commitment. I published my first book on techniques of microstructural analysis, in co-authorship with Francisco Ambrózio Filho, in 1985. I am very grateful to see my books distributed throughout several libraries in the country. Although they are all very simple, they are read as well as cited.

I truly enjoy teaching, I have had hundreds, maybe thousands of students and have supervised dozens of students. To this day I am pleased to mentor students and to teach first-year materials science classes at Poli as well as more specific subjects in the final years of undergraduate and graduate studies. I believe the interaction with the industry is fundamental for a professor and researcher in the area of engineering. More than half of the work I did was in cooperation with the industry.

SBPMat Bulletin: Your trajectory in research and management in institutions of the nuclear energy segment is significant. From your perspective, what are the research materials challenges for the nuclear area?

Angelo F. Padilha: My first job as an engineer was in the nuclear area, in the Coordination of Materials Science and Technology (CCTM) of the Institute of Atomic Energy (IEA), now IPEN-CNEN. The group was created and headed by Professor Shigueo Watanabe. It consisted of about 50 people, nearly all solid-state physicists. My interaction with them was an important school for me.

The applications of nuclear technology include not only nuclear power generation, but also numerous applications in industry, medicine, agriculture, in addition to nuclear propulsion. For example, the number of people who have already benefited from the radioactive drugs produced at IPEN is comparable to the number of people who benefit from the electricity generated by the reactors installed in Angra dos Reis.

Almost all materials used in the construction of a nuclear reactor, a nuclear powered submarine, or a centrifuge for enriching uranium isotopes are materials that were not developed for these applications. In the 1950s, when Americans built the first nuclear-power generating reactor and the first nuclear-powered submarine, in terms of materials, they had to primarily develop uranium and zirconium technology. Hundreds of other materials crucial for the aforementioned applications were already available or only needed some adaptation.

On the other hand, nuclear technologies have some particular characteristics: i) they are dominated by few countries; ii) many of them cannot be purchased on the market; iii) there is little international cooperation, especially in sensitive nuclear technologies; iv) they are complex technologies and require a great deal of human and economic resources to be developed; v) they are generally mature technologies, mastered and perfected over decades. By mastering a mature technology a country can quickly turn it into geopolitical or economic advantage.

Over the last sixty years Brazil has built a nuclear program that can be classified as one of the ten or twelve most important on the planet. Additionally, we have large uranium reserves. From a materials point of view, we still depend on imports, which often encounter enormous obstacles. I believe the biggest challenges and opportunities in the area of materials for nuclear applications lie in national production, in adaptations and in improvements. Future innovations are more likely to be incremental than radical.

SBPMat Bulletin: Leave a message for our readers who are initiating their scientific careers.

Angelo F. Padilha: Go after a consistent scientific education, the rest will be a consequence. A researcher with a deep understanding of the fundamental disciplines such as thermodynamics, crystallography and phase transformation will always be welcome in any research group. Do not be discouraged when facing our gargantuan and tangled bureaucracy.

SBPMat Bulletin: Your name appears in the “interdisciplinary materials commission,” created at the end of 2000 to make possible the foundation of SBPMat. Could you share some recollections or comments about your participation in the creation this society?

Angelo F. Padilha: I believe SBPMat was created at the right time and with the right profile. I consider this to be the main reason for its enduring success. Overall, the “Interdisciplinary Materials Commission” contributed in some way; some more than others. I am certainly among the least contributors. I think the articulating ability of Guillermo Solórzano and the scientific leadership of Edgar Zanotto were decisive. I am proud to have participated in the creation of SBPMat.


Post-doc at IPEN (Brazil) on electroceramics with FAPESP scholarship.

A FAPESP Post-Doctorate Fellowship is available at the Center of Science and Technology of Materials (CCTM), Energy and Nuclear Research Institute, University of S. Paulo, Brazil. CCTM is a member of the Center for Development of Functional Materials, funded by FAPESP.

The candidate will take part on the research on “electric field-assisted sintering of electroceramics”, including experiments on flash sintering (details in (R. Muccillo e E.N.S. Muccillo, J. Eur. Ceram. Soc. 33,2014, p.515-520), X-ray diffraction, scanning electron and scanning probe microscopy, and electrochemical impedance spectroscopy.

The research work aims to provide data for modeling and for proposing physical-chemical mechanisms to explain the flash sintering phenomenon that produces dense ceramic bodies at temperatures lower than conventional, without the grain growth observed in conventionally sintered ceramics.

The interested candidates may send by e-mail a CV (max. 5 pages) with emphasis in their skill on the operation and interpretation of data on electrochemical impedance spectroscopy and sintering, attaching two recommendation letters from their previous supervisors, to Prof. Reginaldo Muccillo (muccillo@usp.br). Additional information may be obtained by sending e-mail to that address. The deadline for the application is November 15, 2016.

Travelling expenses for the selected candidate not living in S. Paulo will be covered by FAPESP.

Information on the fellowship is available in http://www.fapesp.br/en/postdoc.