No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Application of radiotracer methods for troubleshooting and diagnostic in some industrial facilities: NDT perspective
Abstract
Radiotracer method is principally carried out by injection a small amount of radioactive materials as radiotracer at inlet and measures its concentration at outlet of the system being investigated. In modern sense, radiotracer is categorized belong to the group of non-destructive (NDT) methods because it does not disrupt the system. Coventional NDT techniques focus on static examination, whereas radiotracer technique concerns with flow dynamics of liquid and solid in industrial facilities and environment. It is therefore that radiotracer technique is complementary to the other NDT ones. Injection of radiotracer produces residence time distribution (RTD) curves which represent spent time of injected radioisotope particles in the system. When the RTD curves are then used for further analyzing, some information related to the performance of the system could be obtained. In this paper, some applications of radiotracer techniques either for troubleshooting or for diagnostic in some industrial facilities are highlighted. The discussion will focus on radiotracer in single phase and multiphase flow. The state of the art of radiotracer technique is that it is just applied when the system under investigation is being in operation and radiation detection is carried out from outside of the system. To our experience, successful application of radiotracer technique is strongly depending on good preparation, radiotracer selections stages and mode of measurement.
ResearchGate has not been able to resolve any citations for this publication.
Measurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10” outside diameter and contains dry vapor at a pressure of 8 kg/cm² and a temperature of 170 oC. Krypton-85 gas isotope (⁸⁵Kr) has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD) in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT) shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m²/s, calculated from the axial dispersion model.
Received: 21 November 2013; Revised: 16 May 2014; Accepted: 23 May 2014
Weight of mercury in electrolytic cell of soda industry is usually measured gravimetrically, which is typical labor work in character. Error sources of the gravimetric method might have come from the fact that some mercury's are usually trapped in the cell due to complicated structure of electrolytic cell. This cause unknown errors. In addition, formation of amalgam at the cathode may cause a further uncertainty in the measurement. Total error from gravimetric method is 4% on average. Radiotracer dilution method provides advantages either for simplification of procedure and reduction of measurement error. In this experiment radioisotope mercury 203 Hg, which was prepared in nuclear reactor was used to examine 13 of 14 electrolytic cells of soda plant. Each electrolytic cell was designed containing approximately 700 kg inactive mercury. Before injection, the radioisotope mercury was mixed with non radioisotope mercury in a bath to obtain a suitable injection aliquots and standard references. Calibration curve, which was derived from two stage dilution processes taken from standard references, was used to examine degree of mixing between radioisotope and non radioisotope mercury and it was also used in weight calculation of non radioisotope mercury in electrolytic cell. Injection was carried out simply by pouring the injection aliquots into the flowing mercury at the inlet side of the cell. Mercury samples from the cells were extracted at regular time intervals and filled into vials for counting. This was done for the primary conformation of the completeness of mixing of the tracer with the non radioisotope mercury in each cell. When complete mixing is achieved, the unknown quantity of mercury in each cell was calculated based on mass balance principle. From the calculation the weight of mercury in each electrolytic cell was not the same and maximum error of measurement obtained from this method is 2.48 %. Compared to gravimetrically error mentioned above, it was clear that radiotracer dilution method gives better result in terms of higher accuracy and simpler procedure in measurement of the weight of mercury in electrolytic cells. Above all, this method is very suitable to be implemented in soda industry.
Radiotracer signal analysis and recognition still represents challenges in industrial and environmental applications especially in Residence Time Distribution (RTD) measurement. This paper presents a development for the RTD signal recognition method that is based on power density spectrum (PDS). In this development, the features are extracted from the signals and / or from their Higher-Orders Statistics (Bispectrum and Trispectrum) instead of PDS. The Higher-Orders Statistics (HOS) are estimated using direct, indirect and parametric estimations. The recognition results are analyzed and compared for different HOS estimation in order to select the best HOS estimation method for the purpose of RTD signal recognition. The Artificial Neural Networks (ANNs) are used for training and testing of the proposed method. The proposed method is tested using RTD signals obtained from the measurements carried out using radiotracer technique. The simulation results show that the parametric estimation of the Trispectrum gives the higher recognition rate and is the most reliable for the RTD signal recognition.
Turbojet and turbofan engines, rocket motors, road vehicles, aircraft, pumps, compressors, and turbines are examples of machines which require a knowledge of fluid mechanics for their design. The aim of this undergraduate-level textbook is to introduce the physical concepts and conservation laws which underlie the subject of fluid mechanics and show how they can be applied to practical engineering problems. The first ten chapters are concerned with fluid properties, dimensional analysis, the pressure variation in a fluid at rest (hydrostatics) and the associated forces on submerged surfaces, the relationship between pressure and velocity in the absence of viscosity, and fluid flow through straight pipes and bends. The examples used to illustrate the application of this introductory material include the calculation of rocket-motor thrust, jet-engine thrust, the reaction force required to restrain a pipe bend or junction, and the power generated by a hydraulic turbine. Compressible-gas flow is then dealt with, including flow through nozzles, normal and oblique shock waves, centred expansion fans, pipe flow with friction or wall heating, and flow through axial-flow turbomachinery blading. The fundamental Navier-Stokes equations are then derived from first principles, and examples given of their application to pipe and channel flows and to boundary layers. The final chapter is concerned with turbulent flow. Throughout the book the importance of dimensions and dimensional analysis is stressed. A historical perspective is provided by an appendix which gives brief biographical information about those engineers and scientists whose names are associated with key developments in fluid mechanics.
The radioactive tracer technique was used to evaluate the liquid and solid (fine and coarse) transport in two industrial semi-autogenous grinding (SAG) mills. The residence time distribution (RTD), along with the mean residence times, was obtained. The residence times for the liquid and fine solid were equivalent, approximately 2 min, which implies non-significant segregation in this size class. The residence time for coarse solids was approximately 4 min. The RTD was modelled by N perfectly mixed tanks in series, in which the number of equivalent mixers was approximately 2 for liquid and fine solids and approximately 3 for the coarse solids. The coarse particles required additional time to pass the grate discharge restriction, which also favoured the mixing.
The present paper describes measurement of flow rates of cooling water in two large diameter pipelines in a thermal power plant using radiotracer dilution method. The objectives of the measurements were to validate the pumping efficiencies of the Vertical Turbine (VT) pumps used for pumping sea water through the pipelines and also calibrate the installed flow meters. Iodine-131 in the form of sodium iodide dissolved in aqueous solution was employed as radiotracer for flow rate measurements. The measurements were carried out at two different pumping units (Unit-1 and Unit-2) with single as well as with simultaneous operation of the two different, but identical pumps. The measured flow rates in Unit-1 and Unit-2 were found to be 15.4 ± 0.46 m³/s and 14.1 ± 0.43 m³/s, respectively with operation of a single VT pump. Whereas the measured flow rates in Unit-1 and Unit-2 were found to be 27.5 ± 0.82 m³/s and 24.55 ± 0.78 m³/s with simultaneous operation of the two identical VT pumps. The measured pumping efficiency of each individual pump was found to be quite close to the theoretically predicted pumping efficiency, i.e. 15 m³/s. The measured flow rates were also found to be quite different from the flow rates shown by the installed flow meters.
An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation.
Copyright © 2014 Elsevier Ltd. All rights reserved.
The concepts of Danckwerts about the degrees of mixing and segregation are extended to the case of a continuous flow system with an arbitrary but known residence time distribution. For this purpose a life-expectation distribution is defined in addition to the age distribution. Further, a condition of maximum mixedness (minimum segregation) is defined for such a system. This condition, and the condition of complete segregation introduced by Danckwerts, are two opposite extremes. When the system is a reactor in which a chemical reaction of an arbitrary order takes place, the conversion can be calculated for both cases; thus two limits are obtained between which the conversion must lie.
The degree of mixing was first proposed by Danckwerts and further discussed by Zwietering more than 50 years ago to measure mixing performance of a continuous flow system. Although the measure has been widely discussed in mixing literature, there has never been a method to compute its value for a general continuous flow. In this paper, a method is developed to compute this measure for a general steady continuous flow system for the first time. The method is based on the recently developed mean age theory. The governing equations for the mean age and higher moments of age are also derived for different types of tracer introduction other than pulse input in the current mean age theory.
The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fuel flexibility opening the possibility to reduce the nuclear stockpile producing energy from actual LWR irradiated fuel with an efficiency of 45–46%, either in the form of Hydrogen, electricity, or both.
The dispersion of soluble matter introduced into a slow stream of solvent in a capillary tube can be described by means of a virtual coefficient of diffusion (Taylor 1953a) which represents the combined action of variation of velocity over the cross-section of the tube and molecluar diffusion in a radial direction. The analogous problem of dispersion in turbulent flow can be solved in the same way. In that case the virtual coefficient of diffusion K is found to be 10\cdot 1av* or K = 7\cdot 14aU surd gamma . Here a is the radius of the pipe, U is the mean flow velocity, gamma is the resistance coefficient and v* 'friction velocity'. Experiments are described in which brine was injected into a straight 3/8 in. pipe and the conductivity recorded at a point downstream. The theoretical prediction was verified with both smooth and very rough pipes. A small amount of curvature was found to increase the dispersion greatly. When a fluid is forced into a pipe already full of another fluid with which it can mix, the interface spreads through a length S as it passes down the pipe. When the interface has moved through a distance X, theory leads to the formula S2 = 437aX(v*/U). Good agreement is found when this prediction is compared with experiments made in long pipe lines in America.
Thermal output in a nuclear power plant is verified by a calorimetric heat balance on the secondary system of the power plant. The calorimetry involves the precise measurement of the feed water flow rate which should be designed to have ±1:0% of uncertainty. However, the indication of feed water flow rate obtained by a differential pressure measurement across a venturi can be affected by instrument errors, fouling, or a poorly developed velocity profile. These factors can lead to an inaccurate mass flow rate and consequently, an inaccurate estimate of power. The purpose of this study is to develop verification methods with accuracy better than ±0:5% for high-precision flow measurement to be used for measuring feed water flow rate. Such an improvement saves electric power. For a typical Korean nuclear power plant of 1,000MW, 10MW would be potentially saved. This chemical tracer method is a testing process using a tracer, which can be applied to quantify losses in electrical output caused by incorrect measurement of feed water flow rate. This method has a good response to changes in the flow rate. An accuracy better than 0.5% is expected for feed water flow measurement, provided that the feed water system is stabilized during the test.
The rate of a homogeneous reaction depends on rate of encounter between reactant molecules. When the reaction mixture consists of two reactant streams flowing into a continuous reactor, or of earlier and later parts of a single stream, the average rate of reaction is in general dependent on the degree of mixing on the molecular scale. It cannot generally be predicted simply from the distribution of residence times.The author analyses the concept of “mixing on the molecular scale”, gives it a quantitative definition, and shows how it can be measured.Some illustrations of practical interest are given.The problem of a generalised treatment of imperfectly mixed homogeneous reactors is tentatively discussed.
The intellectual roots of residence time theory date back to 1908 and, thus, span the 100-year history of Industrial & Engineering Chemistry. The theory was created, developed, and extended by chemical engineers. It permeates chemical engineering in general and chemical reaction engineering in particular. It also has found widespread utility in the geosciences, environmental engineering, medicine, and biology. This paper provides an overview of the theory and gives some new results here and there.
Concerning the radioisotope dilution method for determining the mercury amount in electrolytic cells in the soda industry, a simple and safe procedure with high accuracy was investigated. The procedure developed is based on the scrupulous supply by the Japan Atomic Energy Research Institute of the aliquots of radioactive mercury, i.e. 197Hg, precisely weighed and the standard reference sample accurately diluted. The intended purpose is achieved with the s.d. in the determination less than 1%
Contenido: Mecanismos de reacción y expresiones de velocidad; Termodinámica de reacciones químicas; Expresión de la velocidad de reacción; Reactores industriales y de laboratorio; Introducción al diseño de reactores basado en sistemas ideales; Reactores no isotérmicos; Mezcla de fluidos en reactores; Distribución del tiempo de residencia en reactores del flujo; Modelos en sistemas no ideales; Aplicación de programas computacionales en dinámica y mezcla de fluidos para reactores; Reacciones bioquímicas; Protección en la ingeniería de reactores químicos; Actualizaciones en diseño de reactores.
During the last few years, IBA started the development of an accelerator-based BNCT system. The accelerator is a Dynamitron built by RDI in USA and will produce a 20 mA proton beam at 2.8 MeV. Neutrons will be produced by the (7)Li(p,n)(7)Be nuclear reaction using a thin lithium target. The neutron energy spectrum will be tailored using a beam shaping assembly. This overview presents the current status of the system: after a description of every component, some design issues, solutions and experimental tests will be discussed.
[(131)I] isotope in different chemical compounds have been injected into 24in hydrocarbon transmission pipeline containing approximately 95% water, 3% crude oil, 2% gas and negligible solid material, respectively. The system is operated at the temperature around 70 degrees C enabling fluids flow is easier in the pipeline. The segment of measurement was chosen far from the junction point of the pipeline, therefore, it was reasonably to assume that the fluids in such multiphase system were separated distinctively. Expandable tubing of injector was used to ensure that the isotopes were injected at the proper place in the sense that [(131)I]Na isotope was injected into water layer and iodo-benzene, ([131])IC(6)H(5,) was injected into crude oil regime. The radiotracer selection was based on the compatibility of radiotracer with each of fluids under investigation. [(131)I]Na was used for measuring flow of water while iodo-benzene, ([131])IC(6)H(5,) was used for measuring flow of crude oil. Two scintillation detectors were used and they are put at the distances 80 and 100m, respectively, from injection point. The residence time distribution data were utilized for calculation water and crude oil flows. Several injections were conducted in the experiments. Although the crude oil density is lighter than the density of water, the result of measurement shows that the water flow is faster than the crude oil flow. As the system is water-dominated, water may act as carrier and the movement of crude oil is slowed due to friction between crude oil with water and crude oil with gas at top layer. Above of all, this result was able to give answer on the question why crude oil always arrives behind water as it is checked at gathering station. In addition, the flow patterns of the water in the pipeline calculated by Reynolds number and predicted by simple tank-in-series model is turbulence in character.
Handbook of offshore oil and gas operation (Gulf Prefessional Prublishing
- J G Speight
J. G. Speight, Handbook of offshore oil and gas operation (Gulf Prefessional Prublishing, Massachusette,
2015), cp 6.
Generators for Industrial Application (IAEA Radiation Technology Series No
- Radiotracer Iaea
IAEA, Radiotracer Generators for Industrial Application (IAEA Radiation Technology Series No. 5.
Vienna, 2013).
- K El Korchia
K. El Korchia et al, Appl. Rad. and Iso. 154, 1-8 (2019)
- R B Macmullin
- M Weber
R. B. MacMullin and M. Weber Jr, Trans. Am. Inst. Chem. Eng. 31, 409-458 (1935)
- R B Macmullin
- M Weber
R. B. MacMullin and M. Weber Jr, Chem. Metall. Eng. 42, 254 (1935)
- H J Kandiner
H. J. Kandiner, Chem. Eng. Progress. 44, 383 (1948)
Radiotracer residence time distribution method for industrial and environmental application
IAEA, Radiotracer residence time distribution method for industrial and environmental application,
Training Course Material, (Vienna, 2008)
- H Kasban
- O Zahran
- F E El-Samie
H. Kasban, O. Zahran and F.E. Abd El-Samie, J. Electron, Electr, Eng. 2, 284-292 (2010).
- Sugiharto
Sugiharto et al., Atom Indo. 36(2), 87-91 (2010).