Brazil’s National Nuclear Energy Commission (CNEN – Comissào National de Energia Nuclear) is supporting the development of microreactors to reduce dependence on diesel generators by providing energy to small cities, hospitals, factories and isolated regions. CNEN will advance in the development of this technology through two of its technical-scientific units, the Institute of Energy and Nuclear Research (IPEN – Instituto de Pesquisas Energéticas e Nucleares) in Sao Paulo and the Institute of Nuclear Engineering (IEN – Instituto de Engenharia Nuclear) in Rio de Janeiro.
The project was approved by the Financier of Studies & Projects (Finep – Financiadora de Estudos e Projetos). IPEN will be responsible for research and development of basic materials for the microreactor and IEN will be in charge of the assembly of a subcritical unit – a reduced model of a nuclear reactor, in which there is no self-sustaining chain reaction.
IPEN will work on the development of materials for the microreactor, including for the moderator (beryllium oxide and graphite) and the control rods (boron carbide). The institute will work to enable the domestic production of these materials to ensure a stable and competitive supply. IPEN may also participate in the development of nuclear fuel, especially for larger diameter uranium dioxide (UO2).
According to researcher Jesualdo Luiz Rossi, from the Center for Materials Science and Technology at IPEN, the microreactor project focuses on the study of different moderators, including beryllium oxide, areas that the institute worked on in the past. “IPEN’s involvement with beryllium dates back to the 1960s and 1970s, when there were specific laboratories for handling this powder material, whose toxicity is high. However, this technical knowledge has been lost over time,” he explained.
The Institute saw this as an opportunity to revisit this technical area. This will entail the design and installation of a new laboratory with adequate infrastructure for the safe handling of toxic powders and their large-scale production. “The challenge is to start a new project, taking advantage of the experience gained in the past and moving forward into the future,” he said.
IEN will also pursue research begun in the 1970s, continuing the development of the subcritical unit. “IEN has been working on a subcritical unit project for many years and this was resumed in 2018,” said Francisco Jose de Oliveira Ferreira, head of the Nuclear Engineering Division at the Institute. “We already have several studies in this area, in addition to most of the equipment and components necessary for assembly of the unit.”
The challenge for IEN will be to test the behaviour of neutrons within the reactor and explore other aspects of reactor physics. Through experiments, the institute will seek to prove whether the theoretical calculations correspond to expectations. In addition, IEN will contribute to instrumentation, an area in which it has extensive experience. With updated calculations and the manufacture of fuels by Nuclear Industries of Brazil (INB – Indústrias Nucleares do Brasil), the next step will be feasibility tests.
The project, Development and testing of critical technologies applicable to nuclear microreactors, was awarded by the Finep More Innovation programme, in the category Renewable/Sustainable Energies: thematic line of technologies for energy generation from low carbon sources. The project has a budget of BRL50m ($8.8m) including BRL30m from Finep. The proposal is led by the companies Diamante Geração de Energia, INB and Terminus Pesquisa e Desenvolvimento em Energia.
In addition to CNEN, the project will involve several scientific and technological institutions, including: the Federal University of ABC (UFABC – Universidade Federal do ABC); Federal University of Santa Catarina (UFSC – Universidade Federal de Santa Catarina); Federal University of Minas Gerais (UFMG – Universidade Federal de Minas Gerais); Federal University of Ceara (UFC – Universidade Federal do Ceará); and National Institute of Telecommunications (Inatel – Instituto Nacional de Telecomunicações).
The project also receives support from the Nuclear Development Directorate of the Brazilian Navy (DDNM – Diretoria de Desenvolvimento Nuclear da Marinha do Brasil) and the Blue Amazon Defense Technologies (AMAZUL – Amazônia Azul Tecnologias de Defesa).
The project will last three years and will seek to validate the technical and sustainable feasibility of a low-power nuclear microreactor system to generate about 3 MWe in a 40-foot container, designed to be remotely operated/monitored for more than 10 years without the need for refuelling. CNEN noted: “Although there are different projects abroad, such as the microreactor that Westinghouse is developing in the United States for installation in Canada, there is still no consolidated technology in this area. The Canadian project, initially planned for 2027, has been postponed to 2029. In Brazil, the approach will be different: the project is not based on the adaptation of foreign technologies, but rather on the development of a totally national solution, based on scientific research and accumulated experience in the nuclear sector.”
Professor Joao Moreira from UFABC, the technical coordinator of the project, noted: “As yet, there is no microreactor operating in the world with established technology. We are developing something original, based on our technical and industrial competence, drawing on the experience of the Navy, IPEN and IEN nuclear programme.”
Adolfo Braid, project coordinator and director of Terminus, said IPEN will be able to expand its participation in the construction of the microreactor as new demands arise. “IPEN, with its nuclear tradition and historic collaboration with the Navy, will play an essential role in the project, especially in the supply chain.”
The project provides for the manufacture of critical components for the microreactor, including the core, reflector and control rods, as well as the passive heat transfer system, composed of heat pipes. The development of the microreactor safety and control system, instrumentation and remote monitoring/control are also planned to ensure the safety and operational efficiency of the reactor.
The heat pipes, which remove heat and thermally stabilise the reactor, will require innovative engineering solutions. Some of the science and technology institutions involved in the project are already working on the feasibility of this system, which will be essential for the reliability of the technology.
Currently, the project is at technology readiness level TRL 3 – the mathematical modelling phase and preliminary studies. The objective is to advance to TRL 6 in which the technology is demonstrated in a relevant environment, closer to practical application. TRLs are a method for estimating the maturity of technologies during the acquisition phase of a programme.
To achieve this goal, four Technology Development Units will be developed to enable essential testing, including operation at low power, critical reactivity measurements, and validation of the heat transfer system. In addition, a microreactor control and protection system will be implemented, consolidating the technology at a more advanced level and close to practical application.
CNEN said project management will be a challenge, especially due to the need to coordinate different universities and research institutes throughout the country. To ensure the efficient monitoring of activities, management software will be adopted, allowing the updating of tasks in real time and the optimisation of planning.
