Brazilian Association of Nuclear Energy
Dec 12, 2019
Early Design Review of Angra 1 (0:29)
0:29-9:22 (Claudio Almedia reflects on his international nuclear education and how it prepared him for a design review of Brazil’s first nuclear plant, Angra 1)
Q: How did your start in nuclear begin?
A: Claudio Almeida was born in North Brazil, but moved South when he was still a baby. He received his degree in electrical engineering at the University of Rio Grande do Sul, taking an additional Introduction to Nuclear course in his final year of his studies. At the conclusion of this course, Claudio went to São Paulo to pursue his Master’s, the home of what is now IPEN, the Nuclear and Energy Research Institute. At this time, he was being trained as an operator of the research reactor. Claudio was selected as one of eight students to go to Rio de Janeiro to participate in the Special Master’s Program. After completing the program, Claudio was accepted to MIT, where he stayed for four years working on his PhD focused on simulation of kinetics problems in reactors. Once finished, he returned to Brazil, who had started construction of Angra 1 and signed a large technical agreement with Germany related to the transfer of technology for nuclear energy. This transfer included the whole fuel cycle, from mining to enrichment, fabrication, and reprocessing.
At this time, Brazil was growing at 12% a year and nuclear was an energy solution because the hydro plants in the South and East were exhausted and were very far away in the North. Increased nationalization was also a goal of the country, but a well-planned program was met with poor execution and an economics crisis. Claudio decided to stay at CNEN, the National Nuclear Energy Commission, which had created the first technical group to do a review and analysis in the license of the Angra 1 plant. This group, called Core Analysis Group, did an analysis on the core and other groups were developed later to analyze civil and mechanical engineering and instrumentation and controls. Claudio was put in charge of Mission Angra 1, the review and analysis of Angra 1 and, later on, the commissioning and inspection of the plant. When the director of the division of nuclear safety from IAEA came to Brazil, a technical cooperation project was proposed with the assistance of the Agency and U.S. Nuclear Regulatory Commission (NRC). Claudio went to the the NRC’s simulator to be trained to license new operators. The D2 steam generators had a vibration problem abroad, which affected plants across the world. Brazil decided to halt the commission of Angra 1 plant to wait for a technical solution, at which point Claudio moved to Vienna.
Analysis of Soviet-designed Reactors (9:22)
9:22-21:09 (How technical issues in Soviet-designed nuclear power plants were identified, analyzed, and corrected to improve plant performance)
Q: Tell me more about how these technical issues influenced what the industry did at that point moving forward.
A: Multiple power plants abroad had common vibration issues with the D2 steam generators. Sweden did some mock-ups and experiments, leading to Westinghouse discovering the problem and implementing it worldwide. The Krško Nuclear Power Plant, in what was then Yugoslavia, is a sister plant to Angra 1. In 1980, the plant requested assistance from the Agency who organized a group to go look at the plant. Claudio Almeida was invited to participate in this mission under the Division of Nuclear Safety at IAEA. He performed calculations for review and analysis of nuclear power plant designs, focusing on accident analysis. The idea was to put computer codes that do the moedling in the agency’s computer and make them available for people to come and do the calculations. However, this meant that only countries located close to Vienna would be able to use the computer; these neighboring countries all used Soviet-designed reactors. Claudio began to be involved with the design of Soviet reactors right at the beginning of the Cold War, making it very difficult to work on from a political point of view. He organized meetings between countries to exchange information on calculations and identifying problems and solutions of the plants. The Agency supported Hungary’s development of a VVER simulation facility, sharing equipment with Hungary in exchange for the test data.
Some of the VVER-440 technical troubles early on stemmed from a design that had a very limited design basis accident. These reactors had six loops, so the accumulator doesn’t inject at all the loops. If one loop breaks, where the accumulator is determines a different progression of the accident. The VVER-440 also doesn’t have containment and the pumps don’t have large flywheels, limiting the inertia of the pumps. After working on this project for seven years, Claudio began preparing to return to Brazil, but Chernobyl happened and the Soviet Union came to an end. From Chernobyl, Europe realized that an accident anywhere is an accident everywhere. Western Europe got scared and decided that it wasn’t sufficient just for their reactors to be safe; they wanted reactors across the border to be safe.
Ripple Effects of Chernobyl Across the Globe (21:09)
21:09-31:22 (Claudio explains how Chernobyl changed the international nuclear industry and how safety missions were conducted at VVER and RBMK sites)
Q: Tell me more about the safety evaluation of the VVER.
A: The Agency started a special project to improve the safety of the VVER’s, supported by the European community. The EBRD (European Bank for Reconstruction and Development) created a large fund for the project. Claudio Almeida was hired by the project because he was the only person that worked on these reactors for seven years. The first thing done was a focused design review of the VVER-440 V230. Deficiencies were identified and a safety mission was called at each of the sites. The safety mission was a combination of the design review and operational review. Claudio’s first mission was at Bohunice in Slovakia, followed by Novovoronezh and Kola in Russia, and Kozloduy in Bulgaria. All the problems were connected to deficiencies in instrumentation and controls. Of the hundred deficiencies identified, all action items were ranked based on criticality of fixing the deficiencies.
The next step was the VVER-440 213, a more modern reactor design. The same safety analysis was completed. The next step was the 1000MW reactors in Russia and Ukraine, followed by a review of the RBMK’s. Lithuania had the largest RBMK’s at the time; these reactors were also in Russia and Ukraine. In spite of the recent accident, two of the reactors at Chernobyl were still operating and shut down much later on. Over time at the end of the Soviet Union, countries started to create lateral agreements with the U.S. and European communities and also divided themselves into other countries. The special project for Soviet-designed reactors became less important and Claudio decided to return to Brazil, where Angra 2 was finally being finished.
Claudio returned to CNEN and got involved with the safety convention. One of the consequences of Chernobyl was making sure all the reactors had the same level of safety. Immediately after Chernobyl, two international conventions were developed. One involved the notification of an accident, which the Soviets didn’t do during Chernobyl. The second involved assistance in case of accident, because some countries couldn’t cope with the aftermath of an accident. The Convention of Nuclear Safety was developed as part of the International Nuclear Safety Regime.
Brazil’s Current Nuclear Climate (31:22)
31:22-44:56 (A look at new nuclear organizations developed after Chernobyl and the current state of Brazil’s nuclear climate)
Q: What was the next phase of your career?
A: When Claudio Almedia returned to Brazil, Claudio served as an advisor to the Director of Nuclear Safety in CNEN. He was later invited to be an advisor to the President of CNEN on matters of safety. The International Nuclear Safety Regime involves three pillars: the binding safety conventions, the international accepted nuclear safety standards, and a system of peer review. When Claudio came to the Agency, the international standards were the NUSS (Nuclear Safety Standards) program. This was reorganized after Chernobyl because they realized much more detail was needed. The Commission for Nuclear Safety Standards was created with four committees: nuclear safety, radiation protection, waste, and transport. Each committee was responsible for developing their own standards. After Three Mile Island in the U.S., the Institute of Nuclear Power Operations (INPO) because the importance of nuclear operators was realized. After Chernobyl, the World Association of Nuclear Operators (WANO) was created, covering all countries. At the same time, the IAEA had the safety review missions and did review of the plants like WANO, but also reviewed seismic design, radiation protection, and transportation. The Agency also developed the IRRS (International Regulatory Review Service), which reviews the regulatory service of a country. Claudio participated in a mission in the United Arab Emirates during the start of construction, in Belgium, which has two regulatory bodies, and in Chile, which doesn’t have nuclear power plants, but has research reactors. The Agency documents and standards state they should be apply in a graded approach, meaning the requirements may be looked at and reconsidered based on the risk of a facility.
During Claudio’s time at CNEN, he got involved with the licensing of Angra 2 and the Navy’s lead-based nuclear reactor. With changes in government, Claudio decided to retire, but still got involved with some of the IAEA activities. He also got involved with the World Nuclear University (WNU), first as a lecturer, than later on as a mentor. Claudio took a two year break from everything nuclear, but got a call last year from ABEN. He was always involved with LAS-ANS, the Latin Amerian Section of the American Nuclear Society. Brazil has ten societies related to nuclear in Brazil, including physics, medicine, biophysics, and radiation protection. ABEN is the largest organization in scope, covering all the areas of energy, applications, and utilization. Nuclear energy is important to the world because consumption of energy will increase, especially in developing countries. Although there is very good progress in wind power and solar power, these plants have a problem of being intermittent. In Northeast Brazil, there is a good possibility of using wind power, but nuclear energy is needed as a base. In the rest of the world, China and India need power and are constructing several reactors. Many countries in Europe are also constructing new reactors. Everyone is relying on nuclear power for the base loads, with the advantage that the plants can be placed near the consumption centers without relying on nature to produce energy when it wants.