2383 research outputs found
Sort by
Flow measurements in hydrotransport units using gamma scattering and cross-correlation techniques
Get PDFThe proposal of this research was to develop a methodology using gamma radiation and cross-correlation
techniques to measure the speed of ore pellets in a hydrotansport duct. An experimental unit was designed and built to be used in a two-phase flows transport simulation It was used to measure the velocity of the solid
pellets. The flowmeter system consists in two independent systems, each one composed by a NaI (1x1”)
scintillators detector- 241Am gamma source, installed outside the tube, both systems were located in the same
vertical plane and separated by 18.0 cm. As pellets, were produced a variety of specimens with different
compositions in order to verify the methodology. Using this flowmeter was possible to calculate the solid phase
velocity
Multi-criteria model to support decision-making for the remediation of urban areas
Get PDFUnder the environmental modeling Project of radioecology research area of IRD (CNEN), several tools have been developed to support post-emergency activities. Currently, a multi-criteria model is in development with the aim of supporting decision-making processes under the radiological protection point of view. At this stage, we are focusing on the decontamination of urban areas. The model includes five calculation modules: (i) averted doses to the public due to remediation procedures; (ii) occupational exposure of remediation workers; (iii) properties of the wastes generated by a remediation procedure; (iv) classification of each procedure for a specific urban scenario based on previously calculated quantities; and, (v) multi-criteria rank calculation. The classification of procedures is based on two types of criteria previously defined, both also included as input data of the model. The first type, called Subjective Criteria, is based on experts’ opinions collected through questionnaires. The second type, called Technical Criteria, is calculated according to the outputs of the three first modules of the program. The output of the model is a rank order list indicating the priority of procedures to use for each different type of urban environment. The use of results based on criteria and methods developed previously to the occurrence of a contamination event intends not only to provide an input to decision-making processes but also to improve public confidence on authorities responsible for the remediation decisions
Study of transient heat transfer in a fuel rod 3D, in a situation of unplanned shutdown of A PWR
Get PDFThe study, in situations involving accidents, of heat transfer in fuel rods is of known importance, since it can be
used to predict the temperature limits in designing a nuclear reactor, to assist in making more efficient fuel rods,
and to increase the knowledge about the behavior of the reactor’s components, a crucial aspect for safety
analysis. This study was conducted using as parameter the fuel rod that has the highest average power in a
typical PWR reactor. For this, we developed a program (Fuel_Rod_3D) in Fortran language using the Finite
Elements Method (FEM) for the discretization of a fuel rod and coolant channel, in order to study the temperature distribution in both the fuel rod and the coolant channel. Transient parameters were coupled to the
heat transfer equations in order to obtain details of the behavior of the rod and the channel, which allows the
analysis of the temperature distribution and its change over time. This work aims to present a study case of an
accident where there is a lack of energy in the reactor’s coolant pumps and in the diesel engines, resulting in an unplanned shutdown of the reactor. In order to achieve the intended goal, the present work was divided as
follows: a short introduction about heat transfer, including the equations concerning the fuel rod and the energy
equation in the channel, an explanation about how the verification of the Fuel_Rod_3D program was made, andthe analysis of the results
Use of Wiki Software for the Knowledge Management at the IEN
Get PDFThanks to the broad availability of internet access and the development of browser-based web applications
known as "wikis" (Hawaiian word for "quick, fast"), it became possible for internet users to participate on big
collaborative encyclopedic projects. The best example is Wikipedia, an online encyclopedia based on
MediaWiki that receives contributions from internet users around the world. In this context, the word "wiki"
usually refers to the wiki software itself, and/or the collection of hypertext documents managed by it. Wiki
software allows creating, editing and managing online-shared documents, which become available immediately
after they are created/edited. With such capabilities, wikis can also be used within organizations as tools to
allow its employees to collaborate in the construction of a common knowledge base containing information
relevant to the organization. In such context, the wiki becomes a tool for knowledge management. This article
describes the implementation of the WikiIEN, which is based on MediaWiki, as a tool for knowledge management at the IEN – Instituto de Engenharia Nuclear. This tool aims to improve the sharing of information
among institute researchers, thorough a dynamic common knowledge base that can be on-line updated. In the
article are presented the logical and computational structure of the wiki created for deposit of the knowledge
generated at the IEN
Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network
Get PDFThe volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase’s densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a (137Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose
I0006 - Fita Betacam
No full textDimensão: 9,5x15,5 cm (fita) / 11x17 cm (caixa)Fita betacam, da marca Sony. Contém vídeos de argonauta, válvulas / água, sódio e reator. --- Informações retiradas da etiqueta do objeto, a fita não foi assistida
I0082 - Imagem da construção do Ciclotron
No full textDimensão: 8,8x12,6 cmFoto colorida do início da estrutura para a construção do Ciclotron Compacto de Energia Variável, no Instituto de Engenharia Nuclear, na Ilha do Fundão, Rio de Janeiro
I0095 - Imagem do Ciclotron
No full textDimensão: 8,8x12,6 cmFoto colorida da vista geral do prédio do Ciclotron Compacto de Energia Variável, no Instituto de Engenharia Nuclear, na Ilha do Fundão, Rio de Janeiro
I0103 - Imagem do Ciclotron
No full textDimensão: 18,4x24 cmFoto P&B da vista da R.F. e do Ciclotron Compacto de Energia Variável, no Instituto de Engenharia Nuclear, na Ilha do Fundão, Rio de Janeiro
I0107 - Imagem do Ciclotron
No full textDimensão: 8,8x12,6 cmFoto colorida com vista central do ímã distribuidor do Ciclotron Compacto de Energia Variável, no Instituto de Engenharia Nuclear, na Ilha do Fundão, Rio de Janeiro