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Compact unit producer of the radiotracer CH3 82Br for measurement of flow rate appluing the transiente of time method
No full textDiverse industries, that work with transports of gaseous materials, meet diverse problems by losses in leaks,
obstructions and corrosions, for resolve such problems, exist to technical of radiotracer that have as advantage
huge, to the possibility of will be performed interventions in operational units without the need of stop the line
or change of material transported. For gaseous material transport systems, chose the radiotracer gaseous methyl bromide, CH3 82Br. However, the only impediment is in relation to the strict norms of protection radiological for the manipulation of radioactive gaseous products. For it solve that difficulty, was built a compact unit applied in the production of the radioactive gas, where the synthesis of the radiotracer was realized in the same place of test, being utilized as main reagent the salt radiated of bromide of potassium, K82Br. The synthesis of the gas CH3 82Br was realized in the compact unit that was connected to a system of ducts (fint = 6,4 ± 0,05 mm) built in the laboratory. Two NaI 2” x 2” scintillation detectors were positioned to the long of the pipeline, with a distance between the two detectors of the 1200 ± 12 cm and the flow rate was fixed in 7,5 l/min. The analysis of the displacement of the radiotracer was realized through the application of the transient of time method, whose utilization permitted to do calculations for the measurement of flow rate, and also identify problems such as: leaks, obstructions and corrosions
Radioative materials transportation main routes in Brasil Radiaction Protection aspects about Radioactive Materiasl Trasnportation
No full textThe heavy transportation in Brazil is generally done by highways. The radioactive material transportation
follow this same rule. Whenever a radioactive material is carried by the road, by the sea or by the air, in some
cases, a kind of combination of those transportation ways, the transport manager has to create a Transportation Plan and submit it to CNEN. Only after CNEN´s approval, the transportation can be done. The plan must have the main action on Radiation Protection, giving responsabilities and showing all the directing that will be take. Although, the brazilian´s highways are not in good conditions, one could say that some of them are not good enough fot any kind of transportation. But we are facing radioactive material use increase but the hospitals and industries, that the reason it´s much more commun that kind of tansportation nowadays. So, because of that, a special attetion by the governments must be provide to those activities. This paper goal is to show the real condictions of some importants highways in Brazil in a radioactive protection´s perpective and give some suggestions to adjust some of those roads to this new reality
Application Of Integrated Optimization To The Control Room Air-Conditioning System Of The Angra I Nuclear Power Plant
Get PDFExperience gained on systems design, operation, and maintenance, with increasing degree of complexity, and the growth of computational processing capacity, allow the development and the application of integrated optimization techniques, which take into account the interaction of all involved phases in systems operation. Such a broad approach, which describes in an integrated way the related factors, from the structure conception to maintenance policies, makes the problem more complex. Generally, the original problem is cast into a simpler one, by imposing some degree of linearity, which allows for a more conventional treatment. However, as long as the description of some parameters is allowed to undergo modifications, the resulting model becomes less realistic. In this work, a mathematical model to be used in integrated optimization of systems performance, which treats the original problem without performing any transformation, is applied to the Control Room Air- Conditioning and Ventilating System (ACS) of the Angra I Nuclear Power Plant. The optimization process treats, in a simultaneous and integrated way, design modifications, system and components availability, redundancy allocation, maintenances/tests scheduling and costs. In a first step, the problem is presented, briefly describing the system design and explaining the options of structure modifications. After that, the optimization is performed, giving as result the final optimal system structure with the respective maintenances/tests scheduling for all components. Genetic algorithms were used as the solutions search tool. The results show the applicability of the integrated optimization to real safety systems, verifying its validation as an instrument of systems optimization and performance analysis
Modelling of stratified gas–liquid two-phase flow in horizontal circular pipes
No full textEste artigo relata investigação numérica e experimental do escoamento bifásico gás-líquido estratificados em tubos circulares horizontais. A média de Reynolds equações de Navier-Stokes (RANS) com o modelo de turbulência k-ω para um fluxo de duas fases gás-líquido estratificada totalmente desenvolvida são resolvidos utilizando o método do elemento finito. Uma superfície de interface lisa é assumido, sem considerar os efeitos das ondas interfaciais. A continuidade da tensão de corte através da interface é imposta com a continuidade da velocidade de ser automaticamente satisfeito pela formulação variacional. Para cada posição de interface dada e gradiente de pressão longitudinal, um circuito de iteração interior corre para resolver as equações não lineares. O esquema de Newton-Raphson é usado para resolver as equações transcendentes por uma iteração exterior para determinar a posição da interface do gradiente de pressão e para um dado par de caudais volumétricos. Favorável comparação dos resultados numéricos com resultados experimentais disponíveis indica que o modelo k-ω pode ser aplicado para a simulação numérica de escoamento de duas fases gás-líquido estratificado.This paper reports numerical and experimental investigation of stratified gas–liquid two-phase flow in horizontal circular pipes. The Reynolds averaged Navier–Stokes equations (RANS) with the k–ω turbulence model for a fully developed stratified gas–liquid two-phase flow are solved by using the finite element method. A smooth interface surface is assumed without considering the effects of the interfacial waves. The continuity of the shear stress across the interface is enforced with the continuity of the velocity being automatically satisfied by the variational formulation. For each given interface position and longitudinal pressure gradient, an inner iteration loop runs to solve the non-linear equations. The Newton–Raphson scheme is used to solve the transcendental equations by an outer iteration to determine the interface position and pressure gradient for a given pair of volumetric flow rates. Favorable comparison of the numerical results with available experimental results indicates that the k–ω model can be applied for the numerical simulation of stratified gas–liquid two-phase flow
METODOLOGIA PARA PROJETO DE INTERFACES E EQUIPAMENTOS NUCLEARES COM ABORDAGEM CENTRADA NOS USUÁRIOS E NA SUA ATIVIDADE
Get PDFThe design of a system based on users and their activity is a process
performed with a focus on people, the work and the available technology. The
involvement of users will particularly benefit from the development,
related to the intrinsic quality and acceptance of the system. This is the safest way
to ensure that the developed system meets the explicit and implicit requirements of
users, and thus be accepted by them. The main objective is to ensure the participation
future users throughout the development process, emphasizing the
application of ergonomic concepts, usability criteria, following the standards
ergonomic contained in the standards and human factors guides, optimize the efficiency of
interaction users equipment and increase operational reliability. The goal
This paper presents a methodology for interface design and
nuclear equipment, using an approach centering on users and their
activity.O projeto de um sistema centrado nos usuários e na sua atividade é um processo
realizado com foco nas pessoas, no trabalho realizado e na tecnologia disponível. O
envolvimento dos usuários deve trazer importantes benefícios para o desenvolvimento,
ligados à qualidade intrínseca e à aceitação do sistema. Esta é a forma mais segura
de garantir que o sistema desenvolvido atenda os requisitos explícitos e implícitos dos
usuários, e assim, seja por eles aceito. O objetivo principal é garantir a participação
dos futuros usuários durante todo o processo de desenvolvimento, enfatizar a
aplicação dos conceitos ergonômicos, critérios de usabilidade, seguindo os padrões
ergonômicos contidos nas normas e guias de fatores humanos, otimizar a eficiência da
interação usuários equipamento e aumentar a confiabilidade operacional. O objetivo
deste trabalho é apresentar uma metodologia para projeto de interfaces e
equipamentos nucleares, utilizando uma abordagem centrada nos usuários e na sua
atividade
Caracterização de uma matriz detectora cintiladora para aquisição de imagem 2D da região folicular da Glândula Tireóide por emissão radioativa usando simulação Monte Carlo
Get PDFThe image acquisition methods applied to nuclear medicine and radiobiology are a valuable research study for determination of thyroid anatomy to seek disorders associated to follicular cells. The Monte Carlo (MC) simulation has also been used in problems related to radiation detection in order to map medical images since the improvement of data processing compatible with personnel computers (PC). This work presents an innovative study to find out the adequate scintillation inorganic detector array that could be coupled to a specific light photo sensor, a charge coupled device (CCD) through a fiber optic plate in order to map the follicles of thyroid gland. The goal is to choose the type of detector that fits the application suggested here with spatial resolution of 10 m and good detector efficiency. The methodology results are useful to
map a follicle image using gamma radiation emission. A source - detector simulation is performed by using a MCNP4B (Monte Carlo for Neutron Photon transport) general code considering different source energies, detector materials and geometries including pixel sizes and reflector types. The results demonstrate that by using MCNP4B code is possible to searching for useful parameters related to the systems used in nuclear medicine, specifically in radiobiology applied to endocrine physiology studies to acquiring thyroid follicles images.Os métodos de aquisição de imagem utilizados em medicina nuclear e na radiobiologia são valiosos na determinação da anatomia da glândula tireóide na busca de anormalidades associadas ao comportamento das células foliculares. A simulação baseada no método Monte Carlo (MC) também tem sido muito utilizada na solução de problemas relacionados à detecção da radiação visando o mapeamento de imagens médicas desde a evolução da capacidade de processamento dos computadores pessoais (PC). Este trabalho apresenta um estudo inovador para encontrar o tipo adequado de matriz cintiladora, que uma vez acoplada a um dispositivo CCD (Charge Coupled Device) através de uma placa de fibra ótica, pode ser aplicado no mapeamento de imagens de folículos da glândula tireóide. A metodologia utiliza a técnica de imageamento por emissão gama e a simulação MC, visando o desenvolvimento de um sistema capaz de obter uma imagem com resolução espacial de 10 m e boa eficiência do detector. A simulação do conjunto fonte-detector foi realizada por meio do programa MCNP4B (Monte Carlo para nêutron próton transporte) para diferentes energias, materiais detectores e geometrias, incluindo tamanho de “pixel” e tipos de materiais refletores. Os resultados alcançados mostram que utilizando o MCNP4B é possível estudar e avaliar parâmetros úteis relacionados aos sistemas utilizados em medicina nuclear, especificamente em radiobiologia aplicada a estudos da fisiologia endócrina no mapeamento de imagens de folículos tireoideanos
A polynomial analytical method for discretre ordinates problems in slab geometry
No full textIn this work we evaluate polynomials approaches to obtain transfer functions that appear in SGF auxiliary
equations (Green´s Functions) for one-group energy linearly anisotropic scattering Sn equations in onedimensional Cartesian geometry. We use Lagrange Polynomials for this task, and we compare the results
with standard SGF Method. This work appears as a preliminary investigation of a new proposal for the
handling leakage terms that come to light in the two transverse-integrated one-dimensional Sn equations
when we use the Exponential SGF Method (SGF-ExpN)
Assesment of array scintillation detector for follicle thyrioid 2D-image acquisition using Monte Carlo Simulation
No full textThis work presents an innovative study to find out the adequate scintillation inorganic detector array to be used coupled to a specific light photo sensor, a charge coupled device (CCD), through a fiber optic plate. The goal is to choose the type of detector that fits a 2-dimensional imaging acquisition of a cell thyroid tissue application with high resolution and detection efficiency in order to map a follicle image using gamma radiation emission. A point or volumetric source –detector simulation by using a MCNP4B general code, considering different source energies, detector materials and geometry including pixel sizes and reflector types was performed. In this study, simulations were performed for 7x7 and 127x127 arrays using CsI (TU) and BGO scintillation crystals with pixel size ranging from 1x1 cm2 to 10 x 10 µm2 and radiation thickness ranging from 1 mm to 10 mm. the effect of all these parameters was investigated to find the best source-detector system that result in an image with the best contrast details. The results, showed that it is possible to design a specific imaging system that allows searching for in-vitro studies, specifically in radiobiology applied to endocrine physiology
Pratical method of breast attenuation correction for cardiac spect
No full textThe breast attenuation effects on SPECT (Single Photon Emission Tomography) myocardium perfusion
procedures have been lately scope of continuous inquiry. The requested attenuation correction factors are
usually achieved by transmission analysis, making up the exposure of a standard external source to the SPECT, as a routine step. However, its high cost makes this methodology not fully available to the most of nuclear medicines services in Brazil and abroad. To overcome the problem, a new trend is presented in this work, implementing computational models to balance the breast attenuation effects on the left ventricle anterior wall, during myocardium perfusion scintigraphy procedures with SPECT. A neural network was put on in order to provide the attenuation correction indexes, based upon the following patients individual biotypes features: mass, age, height, chest and breast thicknesses, heart size, as well as the imparted activity intake levels
