ANA PAULA GIMENES TESSARO

ANA PAULA GIMENES TESSARO

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Antifragility and radioactive waste management
2021 - SMITH, RICARDO B.; TESSARO, ANA P.G.; MARUMO, JULIO T.; VICENTE, ROBERTO
It is not possible to quantify the future, since it is unknown to us. Mathematical models fail when the ambiguity of facts overrides them. Nevertheless, the traditional risk management, with its difficulty in predicting elements that challenge the linear thinking, has in recent years had a strong partner: Antifragility. Unlike disciplines that seek to mitigate the risks of the unpredictable, antifragility views uncertainty as desirable and necessary. It is a recent discipline that breaks the paradigm of always being more effective and efficient; instead, the focus is on the fragile points of an institution, and how to incorporate in it the ability to get stronger over time, as it is subject to stress. Decision making is ultimately a bet. And when it comes to strategic decisions, these are usually high-risk bets because they financially affect the organization, or even the safety of a group, a city, or a country. And the vast majority of decisions are increasingly being made in situations without the full picture of a defined causal model being available. In the case of the nuclear area, it is a field of intense control due to the risk of excessive radiological exposure, and as such it requires a rigorous and continuous risk management, including the management of radioactive waste which is produced in its most various fields of action. Based on this approach, this work seeks to analyze possible fragilities in the institutional, staff and technological areas of the Radioactive Waste Management Service of the Nuclear and Energy Research Institute, in the city of São Paulo, and therefore present potential solutions under the perspective of antifragility, aiming at improving the safety of the human being and the environment.
Knowledge management in the decommissioning of nuclear facilities in Brazil
2021 - SMITH, RICARDO B.; SALVETTI, TEREZA C.; TESSARO, ANA P.G.; MARUMO, JULIO T.; VICENTE, ROBERTO
In the second half of the twentieth century in Brazil, several nuclear facilities were built for the most varied objectives. The largest number of such facilities is at the Nuclear and Energy Research Institute in São Paulo (IPEN-CNEN/SP). For different reasons, some of these facilities had their projects finalized and were deactivated. Some of the equipment was then dismantled, but the respective nuclear and radioactive material remained isolated in the original sites awaiting the proper decommissioning procedures. The Celeste Project is an example of a facility where the nuclear material has been kept, and is subject to Argentine-Brazilian Agency for Accounting and Control of Nuclear Materials (ABACC) periodic inspections. Because of a number of interests, including financial and/or budgeting situations at the institutions, decades have passed without any further action, and the people who withhold information and knowledge about these facilities have already moved away from the area or are in the process of. Therefore, this work proposes an analysis about the knowledge management reflecting on the possible consequences for the decommissioning processes, in case of loss of the knowledge acquired.
Further analyses of the unburied Goiania accident packages
2021 - SMITH, RICARDO B.; TESSARO, ANA P.G.; ROLINDO, NATALIE C.; VICENTE, ROBERTO
In 1987, in the city of Goiania, Brazil, a derelict teletherapy machine was disassembled by scavengers and Cs-137 was released in the environment, unleashing the biggest radiological accident in Brazil. During the 15 days before the accident was acknowledged, some contaminated materials were sold and delivered to recycling factories in a few cities in the state of Sao Paulo, Brazil, in the form of metal scrap and recycled paper bales. The contaminated material was then collected, the metal scrap was conditioned in forty-three 200-liter drums, and the paper bales were stored in fifty 1.6 cubic meter steel boxes at the interim storage of the Nuclear and Energy Research Institute (IPEN), in the city of Sao Paulo, and there remained ever since. In 2017, 30 years later, initial analyses were performed at a sample of these boxes, checking for their activity, weight, and incongruences between the original values recorded at the time of collection and the measurement results 30 years later. The results indicated that none of the boxes checked were close to the clearance limit and that, without any sort of treatment, this radioactive waste should be stored for at least 150 years more. Visual inspection could not be performed at that time. Nowadays, some of the boxes were opened and samples from the contaminated material inside were taken for analysis. The main objective of this work is to report the results from the evaluation of the physical state of this material. After these analyses, the treatment options for volume reduction that were previously proposed were reviewed, and the method that best suits the current characteristics of the waste was chosen.
Opening the Goiânia accident unburied waste packages
2021 - TESSARO, ANA P.G.; GERALDO, BIANCA; SOUZA, DAIANE C.B. de; SMITH, RICARDO B.; VICENTE, ROBERTO
The year 2017 marks 30 years since the radiological accident in Goiânia, Brazil, which resulted from the leakage of Cs-137 from a teletherapy equipment. The contaminated material collected during the response to the accident was disposed of in Abadia de Goiás, about 20 km from Goiânia. However, in the initial 15-day period before the authorities were notified, contaminated paper bales and scrap metal were sold and transported to material recycling facilities in the State of São Paulo, one thousand kilometers away. These materials were later collected in steel boxes and drums, and stored in the intermediate waste storage facility of the Nuclear and Energy Research Institute - IPEN, in São Paulo. The objective of this paper is to describe the work performed to check the present condition of the paper bales waste boxes, reassess the reported Cs-137 activities, and evaluate possible treatment methods that can be applied to reduce the volume of waste. Prospective waste treatment methods are discussed.
Essays on nuclear energy and radioactive waste management
2021 - TESSARO, ANA P.G.; GERALDO, BIANCA; SOUZA, DAIANE C.B. de; ROMERO, FERNANDA; BISURI, INDRANIL; MARUMO, JULIO T.; CHEBERLE, LUAN T.V.; SACHDEVA, MAHIMA; ROSA, MYCHELLE M.L.; ROLINDO, NATALIE C.; SMITH, RICARDO B.; VICENTE, ROBERTO; SALVETTI, TEREZA C.
Preliminary studies on electron beam irradiation as a treatment method of radioactive oil sludge
2021 - TESSARO, A.P.G.; VICENTE, R.; MARUMO, J.T.; TEIXEIRA, A.C.S.C.; ARAUJO, L.G.
Radiation-induced advanced oxidation processes have been proposed for the treatment of various types of wastes. However, electron beam technologies for the removal of recalcitrant compounds in petroleum wastes are still poorly understood. This work aims at evaluating the effects on the degradation of organic matter from oil sludge by electron beam irradiation. Characterization methods were employed to identify the chemical elements present in the waste. Radiometric analysis was performed to identify radionuclides and measure dose rates. Preliminary immobilization of the untreated waste with cement indicated resistance values very close to the minimum established in national regulation. To treat the waste, an electron beam accelerator, model Dynamitron II, with variable current up to 25 mA was employed and the irradiation doses ranged from 20 to 200 kGy. Solutions were prepared with an initial H2O2 concentration of 1.34 mol·L-1. The effects on the removal of total organic carbon are discussed.
Knowledge management in the decommissioning of nuclear facilities in Brazil
2020 - SMITH, R.B.; SALVETTI, T.C.; TESSARO, A.P.G.; MARUMO, J.T.; VICENTE, R.V.
In the second half of the twentieth century in Brazil, several nuclear facilities were built for the most varied objectives. The largest number of such facilities is at the Nuclear and Energy Research Institute in São Paulo (IPEN-CNEN/SP). For different reasons, some of these facilities had their projects finalized and were deactivated. Some of the equipment was then dismantled, but the respective nuclear and radioactive material remained isolated in the original sites waiting for the proper decommissioning procedures. The Celeste Project is an example of a facility where the nuclear material has been kept, and is subject to Argentine-Brazilian Agency for Accounting and Control of Nuclear Materials (ABACC) periodic inspections. Because of a number of interests, including financial and/or budgeting situations at the institutions, decades have passed without any further action; the people who originally worked there, and possessed information and knowledge about these facilities, have already moved away from the area, or are in the process of. Therefore, because of the absence of knowledge management techniques in force at the time of establishing and operating these installations, this work proposes an analysis about the possible consequences in case of loss of perhaps the only one remaining knowledge, the one from the people who designed those departments and worked there.
Desenvolvimento de métodos radiométricos para a caracterização de rejeitos radioativos
2015 - TESSARO, ANA P.G.
A aceitação de rejeitos radioativos em um repositório final depende, entre outras coisas, do conhecimento do inventário radioisotópico presente neles. Para obter essa informação, é necessário fazer a caracterização primária dos rejeitos de modo que a composição seja conhecida e oriente os passos seguintes da gestão. Os filtros cartucho que são utilizados no sistema de retratamento de água do reator de pesquisa IEA-R1 é um desses rejeitos. O IEA-R1 é um reator de pesquisa do tipo piscina, operando entre 2 e 5 MW, que utiliza a água como líquido de arrefecimento, moderador e blindagem biológica Além do seu uso em pesquisa, também é utilizado para produzir radioisótopos e irradiar amostras. Ele está localizado no Instituto de Pesquisas Energéticas e Nuclear, no campus da Universidade de São Paulo. Os filtros cartucho são utilizados para reter o material particulado em suspensão presente na água. Quando os filtros ficam saturados e são incapazes de manter o fluxo dentro dos limites estabelecidos, eles são substituídos e descartados como rejeito radioativo. Após um período de espera para o decaimento da atividade, são enviados para Gerência de Rejeitos Radioativos (GRR). O objetivo deste trabalho é apresentar os estudos realizados para determinar a atividade dos emissores gama presentes nos filtros cartucho. As atividades foram calculadas utilizando as taxas de dose medidas com detectores portáteis, as relações entre as taxas de emissão de fótons avaliadas por espectrometria gama, e o método de Point Kernel, que correlaciona a atividade de uma fonte com as taxas de dose a várias distâncias. O método descrito pode ser utilizado para determinar de modo rotineiro o inventário radioisotópico destes filtros, dispensando análises radioquímicas destrutivas, e a necessidade de calibração da geometria de medição.