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Steam turbine: alternative emergency drive for secure removal of residual heat from the reactor cores that use water as coolant after Fukushima
No full textSolution of the spatial kinetic equations using the expansion in pseudo-harmonics: case 2D
No full textThe application of the 3d transient computational fluid dynamics to the radionuclide dispersion
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Quantitative analysis or rare earths by x-ray fluorescence spectrometry
Get PDFRare earths ores and compounds are of growing importance to the worldwide industry. Its applications range from raw material to catalysts, manufacturing of electronics and even supermagnets. Therefore, the demand for quick and accurate quantitative analysis methods is continuously growing. Current quantification methods of rare earths involve the separation of these elements by ion exchange and liquid-liquid extraction prior to the analysis itself, processes both time and reagent consuming. In the present work, we propose a method that directly quantifies by XRF technique the following rare earths: La, Pr, Nd, Sm and Gd in a concentrated liquor whose matrix also contains Ca, Y, PO4, U and Th. We evaluated the analytical interference of each element present on the sample on X-rays spectrum. The studied samples are certified standards and the obtained results have been compared to EDTA titration results, an already well-stablished and widely trusted method. We also measured the matrix effect thus using a complex rare earths standard. Results show that quantification by XRF technique is as accurate as the results in dose titration with EDTA for the same elements, with the advantage of exempting the previous separation step from each rare earth and from other elements present in the matrix (such as U and Th)
Evaluation of management of communication in the actions of preparedness and response to nuclear and radiological emergencies
Get PDFThe use of practices involving the use of ionizing radiation in diverse areas of knowledge increases every day. This growth warning about the increased probability of accidents, radiological and nuclear emergencies, with possible consequences for the public, workers and the environment. Within this scenario, it is clear that studies and reassessments of the emergency response actions, receive proposals for continuous improvement. The achievement of the objectives of the response must be sustained by tactical, operational and logistics optimized processes. The articulation through communication between the teams involved in the response must be adaptable to each accident or emergency, respecting its size. The objective of this study is to perform an assessment on the management of communication in the actions of Preparedness and Response to Nuclear and Radiological Emergencies. This assessment is supported by best practices of the Incident Command System (ICS) and the Institute of Project Management (Project Management Institute - PMI). For this purpose, based on models referred were established performance indicators supported by the BSC (Balanced Scorecard). These indicators allowed to evaluate more objectively the performance of the communication processes associated with each phase of the response. The study resulted in the proposed model documents aiming to assist planning of communications exercises in preparation and response actions, supported and adapted the best practices of PMI. These methodologies were evaluated by real cases selected from radiological and nuclear emergencies published by the International Atomic Energy Agency (IAEA)
An experimental low-pressure facility to study boron transients in the pressurizer of an a integral modular nuclear reactor
Get PDFSmall and medium size modular reactors offer many advantages when compared with typical nuclear plants in various circumstances, such as offering greater simplicity of design, economy of mass production, and reducing siting costs. The integral configuration is characterized by having most of its components inside the pressure vessel, eliminating the probability of accidents. However, for this configuration there is no spray system for boron homogenization, which may cause power transients. Thus, it is necessary to investigate boron mixing. The Federal University of Pernambuco (UFPE), in a partnership with the Regional Center of Nuclear Sciences of Northeast (CRCN-NE) and the Nuclear Engineering Institute (IEN/CNEN-RJ), is developing a project that aims to analyze transients in a compact modular integral reactor. This analysis will be made by using the data obtained from one experimental bench that is mounted at CRCN-NE. A study accomplished in 2012 using a simplified bench (built in reduced scale with a test section manufactured with transparent acrylic) showed that it was possible to obtain preliminary experimental results for the boron homogenizing process
Use of individual protection equipment and collective in case of accident during the transport of radioactive product - class 7
Get PDFThe personal protective equipment (PPE) are devices used by professionals against potential radiological hazards that may threaten the health or safety in the event of an accident or incident during the transport of radioactive material. The collective protection equipment (CPE) devices are used in place of the accident in order to protect people and the environment from risks such as safety signs, among others. This work will be part of the new edition of the NBR 9735 - Set of equipment for emergencies in land transport of dangerous goods - edited by the Brazilian Association of Technical Standards / ABNT - National Standardization Forum which CNEN participates in the Study Committee - B16 namely, dangerous, accounting for Class 7 radioactive materials. The Standard 9735 establishes the minimum set of equipment for emergencies in inland transport of dangerous goods, consisting of protective equipment to be used by the driver and staff involved (if any) in the transport operations of transport units, equipment for signaling, isolation of the area of occurrence (fault, accident and / or emergency). Thus, we will present a set of individual and collective equipment that must accompany the carriage of Class 7 products to meet the radiological accident situations and also establish a training base for the driver as the use of them
Pressure drop calculation in a fuel element of a pool type reactor
Get PDFEven with the advances of hardware in computer sciences, sometimes it is necessary to simplify the simulation in order to optimize the results given the same calculation runtime. The object of this study is a thermodynamic analysis of the core of a pool type research reactor, focusing on natural circulation. Due to the high geometrical complexity of the core, the scale transfer process becomes an essential step to the thermodynamic study of the reactor. This process takes place by determining the effective equivalent properties obtained from a detailed simulation of the core and transferring them to a porous medium having a coarse mesh while preserving the overall characteristics. In this way, it will be able to obtain the quadratic resistance coefficient KQ by calculating the pressure drop inside the fuel element. To observe in detail the behavior of this flow, longitudinal and transversal cross sections will be made in different points, thereby observing the velocity and pressure distributions. The analysis will provide detailed data on the fluid flow between the fuel plates enabling the observation of possible critical points or undesired behavior. The whole analysis was made by using the commercial code ANSYS CFX ver. 12.1. This is study will provide data, as a first step to enable future simulations which will consider the entire reactor