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Radioesterilização de documentos históricos: um estudo da contribuição na degradação de papel e tintas de impressão
Get PDFA exposição controlada à radiação gama é um processo físico que pode ser utilizado na
preservação e recuperação de documentos históricos. Dependendo das características
intrínsecas do material a ser tratado, é necessário pesquisar e estabelecer, de tempos em
tempos, a taxa de dose e a dose total mais adequada, as condições para eliminar ou reduzir o
risco biológico, o equipamento e sua logística, os aspectos econômicos e outros impactos
causados pela radiação no material a ser tratado. As referências indicam que por meio da
pesquisa é possível consolidar o conhecimento a respeito da radiação gama emitida por fontes
de 137Cs ou 60Co de maneira a remover completamente ou reduzir drasticamente infestações
por insetos e biodeterioração por microrganismos. Nesse trabalho foram utilizados dois
irradiadores: um irradiador de pesquisa tipo cavidade com fonte de 137Cs pertencente ao
Instituto de Defesa Química, Biológica, Radiológica e Nuclear do Exercito Brasileiro; e um
irradiador de pesquisa marca MDS Nordion, com fonte de 60Co pertencente ao Laboratório de
Instrumentação Nuclear da Universidade Federal do Rio de Janeiro. O código MCNPX foi
usado para calcular a distribuição de dose em ambos os irradiadores. Tanto as amostras de
papel irradiadas, quanto às não irradiadas foram submetidas a envelhecimento térmico seco e
exposição à radiação ultravioleta, possibilitando a comparação entre diferentes tipos de
envelhecimento. Os resultados dos testes de resistência mecânica e de medição de cor indicam
que, com a dose total adequada, o tratamento por exposição à radiação gama não altera as
propriedades físicas ou mecânicas do papel e tintas de impressão de maneira significativa.
Dessa maneira, é possível concluir que apesar da complexidade do procedimento de
irradiação de documentos históricos, que demanda um estudo detalhado com vistas a
assegurar sua aplicação segura, esta é economicamente interessante quando o equipamento se
encontra disponível sendo ambientalmente mais segura do que o uso de pesticidas químicos
IMPROVEMENT OF RADIATION DOSE ESTIMATION DUE TO NUCLEAR ACCIDENTS USING DEEP NEURAL NETWORK AND GPU
Get PDFRecently, the use of mobile devices has been proposed for dose assessment during nuclear accidents. The idea is to support field teams, providing an approximated estimation of the dose distribution map in the vicinity of the nuclear power plant (NPP), without needing to be connected to the NPP systems. In order to provide such stand-alone execution, the use of artificial neural networks (ANN) has been proposed in substitution of the
complex and time consuming physical models executed by the atmospheric dispersion radionuclide (ADR)
system. One limitation observed on such approach is the very time-consuming training of the ANNs. Moreover,
if the number of input parameters increases the performance of standard ANNs, like Multilayer-Perceptron
(MLP) with backpropagation training, is affected leading to unreasonable training time. To improve learning,
allowing better dose estimations, more complex ANN architectures are required. ANNs with many layers
(much more than a typical number of layers), referred to as Deep Neural Networks (DNN), for example, have
demonstrating to achieve better results. On the other hand, the training of such ANNs is very much slow. In
order to allow the use of such DNNs in a reasonable training time, a parallel programming solution, using
Graphic Processing Units (GPU) and Computing Unified Device Architecture (CUDA) is proposed. This work
focuses on the study of computational technologies for improvement of the ANNs to be used in the mobile
application, as well as their training algorithms
Use of Virtual Reality for the development of a Nuclear Waste Repository for Training
Get PDFIn Brazil the highest amount of waste generated is low and medium level of radiation. Its management and final destination is important for society and the solution, proposed by the government, involves the construction of a National Repository for Radioactive Waste. Using Virtual Reality (VR), this article aims to develop an interactive virtual model of the repository to assist in the study, evaluation, training of personnel and planning of the installation to be implemented. The method was divided into four steps. The first, called "Requirements Specification and Survey", aimed at acquiring information about the terrain and future buildings of the installation in the real world. The next step, known as "Modeling the Environment" is the construction of the virtual environment itself according to the specifications of the previous method. The third, called "Functionality Implementation" consists of inserting functionalities into the system, such as performing some tasks present in the repository. Finally, the last step is the interactive virtual model of the national repository for radioactive waste, with this tool users can study, evaluate and train conditions/situations of the installation. In conclusion, the results have shown that the tool presented in this work is a possible application of the VR for dissemination and training in nuclear installations. Using this tool, users can visualize and plan strategies to be carried out in a repository, without interrupting the operation of the installation. It can be used for training and operations simulations, aiming to improve the processes without exposing the operators to the radiation
The synthesis of radioactive polymeric microspheres for spect imaging during embolization procedures
Get PDFVascular embolization is an important clinical procedure, frequently used to reduce the size of a tumor, to
facilitate the removal of a tumor during surgery or to define a treatment of tumor malformation. In addition, imaging is an important component for the evaluation and care of patients undergoing vascular embolization.
Nowadays, during the embolization procedure, the radiologist uses the Angiography or Fluoroscopy (X-Ray
images) technique to estimate devascularization, since only pathological examinations are able to show the
exact location of the blockade and microspheres. SPECT imaging is widely used in Brazil and provides images
of superior quality to the mentioned techniques. Therefore, radioactive polymeric microspheres can be used as
radioembolization agents for SPECT imaging. This technique can improve the resolution of images and, consequently, the embolization procedure efficacy of uterine fibroids for example, by allowing the track of particles distribution in the veins and tumor, the homogeneity of this distribution and the end of the embolization procedure. In this work, we evaluate the copolymerization of 4-vinylphenol and vinyl acetate as a synthesis route for a new radioembolization agent. GPC analysis results showed that this comonomer presence improved the molar mass distribution. In addition, bulk polymerization tests and kinetic studies showed that the selected comonomer retards the reaction time, but does not decrease the conversion percentage. Indeed, this result points out the necessity of a comonomer chemical modification to improve yield results
Design of a collaborative virtual environment for training security agents in big events
Get PDFThis paper describes a design of a collaborative virtual environment (CVE) for training security agents in
big events. The CVE was modelled with Autodesk 3ds Max, while Unity 3D was used to create the terrain and implement the features that make up a virtual environment.
The Brazilian soccer stadium known as Maracana˜ and its surroundings were chosen as the real counterparts of the CVE. The usability of the CVE was evaluated through
simulations involving security agents dealing with threats related to suspects carrying radioactive material in big events. In order to perform these simulations, we use the same procedures used during 2014 FIFA World Cup and planned to be used in Rio 2016 Olympic Games. The main objective of this work is to verify the feasibility of designing a CVE and its usability for training security agents involved in big events issues. Results indicated that the proposed CVE has been successful concerning both, design and usability, besides of helping to improve the ability of each member of the security team on performing his duty
DEVELOPMENT OF A NEW GRAPHICAL INTERFACE FOR THE LABIHS SIMULATOR USING LABVIEW
Get PDFThe LABIHS (Human-System Interfaces Laboratory) compact nuclear power plant (NPP) simulator is, since 2002, operating at the Nuclear Engineering Institute (IEN), Brazil. Due to the processing power required by the simulator software and the hardware available at the time, the simulator was developed under a PA-RISC architecture server (HPC3700), using the HP-UX operating system. All mathematical modeling components
were written using the HP Fortran-77 programming language with a shared memory to exchange data from/to all simulator modules. In 2008, this hardware/software framework was discontinued, with customer support ceasing in 2013, what makes it difficult to maintain and expand. On the other hand, technological progress during this period enabled cheaper and more accessible computers, such as the PC (Personal Computer)
architecture, to have enough processing power to run the simulator framework. It turns out that the PA-RISC computer architecture is incompatible with the PC one. Thus, our work group has been working, for some years, to port the simulator to the PC architecture. Part of this effort includes completely rebuilding all the MMI (Man-
Machine Interface) using modern software tools and programming languages which are compatible with the PC architecture. In this work, we present two important steps for the NPP simulator migration from the obsolete architecture to the PC one. Firstly, we provide a new inter-process communication library which allows the data exchange between the NPP simulator currently running at the old PA-RISC architecture and other software
running on modern PCs. This step is important because it allows us to work on the new Graphical Interface while the older NPP simulator is still operating. Secondly, we present the all-new MMI for the LABIHS simulator, currently under development using LabVIEW software suit. We then provide a comparison between the original and the proposed MMI development process
TRANSIENT HEAT TRANSFER ANALYSIS UP TO DRYOUT IN 3D FUEL RODS UNDER UNIDEAL CONDITIONS THROUGH THE DEVELOPMENT OF A COMPUTER CODE
Get PDFIn this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the
computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent
the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases
for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the
computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent
the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases
for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the
computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent
the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases
for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric
NaI(Tl) detectors modeling in MCNP-X and Gate/Geant4 codes
Get PDFNaI (Tl) detectors are widely used in gamma-ray densitometry, but their modeling in Monte Carlo codes, such as MCNP-X and Gate/Geant4, needs a lot of work and does not yield comparable results with experimental
arrangements, possibly due to non-simulated physical phenomena, such as light transport within the scintillator.
Therefore, it is necessary a methodology that positively impacts the results of the simulations while maintaining
the real dimensions of the detectors and other objects to allow validating a modeling that matches up with the
experimental arrangement. Thus, the objective of this paper is to present the studies conducted with the MCNP-X and Gate/Geant4 codes, in which the comparisons of their results were satisfactory, showing that both can beused for the same purposes
Radiosterilization of historical documents: the potential effects of gamma irradiation on paper and printing inks
Get PDFThe controlled exposition to gamma radiation is a physical process which can be used for the preservation and
recovery of historical documents. Depending on the intrinsic characteristics of the material to be treated, it is
necessary to research and stablish, from time to time, the optimum dose rate and total dose, the conditions to
eliminate or reduce the biological threat, the equipment and its logistics, the economic aspects and any other
impact caused by radiation on the material to be treated. The references indicate that through research it is
possible to consolidate the knowledge about gamma radiation emitted from 60Co in order to completely remove or at least greatly reduce infestation by insects or biodeterioration microorganisms. On this work we have used a MDS Nordion self-contained 60Co research irradiator, model Gamacell Excel 220, at Postgraduate Institute of Engineering and Research Alberto Luiz Coimbra, in Rio de Janeiro Federal University. The analysis of the samples submitted to controlled thermal dry aging and to gamma radiation made possible to verify the differences between treated and untreated samples. The results of the chromatic measures
indicate that, with the optimum total dose, the gamma radiation treatment does not significantly alter the properties of paper or printing inks. This way, it is possible to conclude that even though the gamma irradiation of historical documents is a complex procedure which demands a detailed study in order to assure its safe application, it is environmentally safer than the use of chemical pesticides
Study of the application of virtual reality in programs training on nuclear technology
Get PDFThe activities developed in the units which organize the National Nuclear Energy Commission (CNEN) are present in various sectors of the Brazilian society, being them in medicine, industry, electricity generation, mining, and among the others. Based on the assumption that the employees are CNEN ́s mayor differential and the training programs play an important role in the process of organizational development, because they align the professionals with the strategies of the institution properly. Focusing on these matters, this master ́s thesis aimed to evaluate the training programs which are applied by CNEN, in order to propose and evaluate the use of the Virtual Reality (VR) expertise as a new method to be applied in the training programs. To accomplish this purpose, we performed two methodological approaches through questionnaires. And from the analysis of the results obtained, we could realize that there was no efficient training program which is systematically applied by CNEN, and the use of the RV technique improves the training programs in the understanding of themes whose assimilation is challengeable, such as those related to nuclear power. In this sense, for a better functional performance, the training programs adopted by CNEN must be structured so as to enable the development of each server ́s skills as well as abilities and, it is actually hoped that the virtual reality tools could be inserted in these programs to pursue only this purpose