Radyoaktif izleme tekniği ile kaçak tayini

Kakaç, Hakan
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Enerji Enstitüsü
Bu tez çalışmasında iki farklı deney düzeneği kurularak, bir kapalı boru sisteminde, sistemde meydana gelen kaçak ve kaçak yerinin bulunması farklı izleme teknikleri kullanılarak incelenmiş ve teknikler arası bir mukayeseye gidilmiştir. Deneyin birinci bölümünde küvet içine bir bora sistemi yerleştirilerek boru cidarında delikler açılmıştır. Borunun üst tarafı toprak ile örtülerek sistemde meydana gelen sızıntının ( Kaçağın ) yeri farklı üç teknik kullanılarak ( Radyoaktif İzleme Tekniği, Görsel izleme tekniği ve Nem İzleme Tekniği ) sızıntının olduğu bölgenin tesbitine gidilerek, bu üç izleme tekniği birbirleri ile kıyaslanmıştır. Deneyin ikinci aşamasında bir akrilik boru hattı kurularak, bu boru hatundan çeşitli debilerde kaçak yapıtırılmış ve kaçak debisine bağlı olarak sistemden geçen sayım miktarları ölçülmüştür. Alınan sayımlar yardımı ile sisteme ait kalibrasyon eğrileri hazırlanmıştır. Sonuçlar radyoaktif izleme tekniği çerçevesinde incelenmiş ve bu teknikle ileri ve hassas sonuçlara ulaşışabileceği gösterilmiştir.
Radioisotopes are playing a more and more important rote in industry. The idea of using tracers ( chemicals, dyes,.etc. ) in the investigation of complex physical phonomena has always attracted the attention of scientists and engineers. Despite the extensive use of this method, there have been few efforte to define it or to clearly enunciate its principles. Significant technological and economic results have been obtained by using radioactive tracers in machine constructions, chemistry, food production, building and other branch of industry. When radioactive isotopes became available it was immediately recognized that they offered an almost ideal solution to trcaer selection. Extensive experience has ben gathered all over the world in the application of radioactive tracers in industry. The application of radiotracer techniques to engineering research is primarily limited only by the imagination and resourcefulness of the experimenter. The radiotracer has probably been responsible for a good part of the general interest in tracing methods within the last 25 years. The tracer method provides information about a system or a part system that often could not be otherwise determined. The tracer method is independent of the distinguishable property used to identify the tracer. VI There are different advantages to the application of radioactive isotopes as a tracer. - Their amount can be determined quantitatively with high sensitivity even in low concentrations. -Chemical labelling is possible, - The isotopes can be detected through the wall of the tube or reactor. - The data of field measurements can be obtained in a computer - compatible form. -It is a simple method. - The detection of a radiotracer is unambiguous if proper detection methods are used. - The minute quantity of tracer required does not introduce density changes. On the other hand, there are different disadvantages to the application of radioactive isotopes as a tracer. - It is essential to ensure the radiation protection of both the experimenters their environment, - Special personal qualification is required for work with radioactice isotopes. When a tracer study is planned, the selection of method should be preceed by a careful consideration of the advalages and disadvantages. When several radiotracers are available, several factors should be considered before a choice is made; -Cost; -Half- life, -Radiations emitted, both type and energy, -Radiation hazard - Availability. vu A radioisotope tracer must represent the behaviour of the material to be traced. When the radioisotope is part of the molecules of the material this conditions is fulfilled. The isotope for labelling should be adapted to the nature of the process and the properties of the material to be studied. A suitable radioisotope tracer may be used to follow the path and rate of movement of the labelled substance under investigation. In any industry, good plant performance and avoidance of shutdown, especially in continuous processes, are of special importance, radiotracer techniques are now available to provide speedly solutions to many plant and process problems., starting from malfunctions in specific components to poor overall plant performance. In many cases, technological parameters are not directly measurable but are functionally tied up with the data obtained from tracer experiment. The tracer method usually involves the use of the tracer to label, or make easily identifiable, a specific phase or part of the system, called the tracer material.The radioisotope or radiotracer is the most universal and practical tracer. The radiotracer has been responsible for a good part of the general interest in tracing methods within the last 25 years. Radiotracer techniques have been used for leak detection. Applications of leak detection can be grouped as detection of leak place and determination of leak quantity. In all sections of industry great importance attaches to research on the detection of leakage in various types of pipe. One of these research projects involving the use of radioactive tracers is that relating to the detection of leaks from the underground piping systems. Especially ; Oil piping systems and water piping systems. VUl The most suitable method for this purpose is the radioactive tracer method. If there is a leak, part of the radiotracer will leave the pipeline with the leaking fluid and be absorbed in the soil around leak. A radiation detector on the surface of the ground above pipeline will indicate the presence of activity and therefore the presence and location of the leak. A particularly important factor is that the work of detecting lekage sites has absolutely no effect on the normal course of production in the plant as a whole or in its individual sectors. In this MSC, thesis, leak place detection experiments will be done for the different flow rates. For these purposes, experiments sets established separately. It is planned that the comperative studies with a conventional techniques. So the comperative evaluation can be done. In the experiments Na - 24 will be used as a radiotracer. Sodium - 24 will be used in sodium carbonate compound and it will be irradiated in İ.T.Ü. TRIGA MARK II Training and Research Reactor. Results of experiments which will be having for the different flow rates for determination of leak quantiyt are given comperativaly and their sensitivity rates. In this thesis, experiments on determination of the place of the leakage has been done pipeline. At the beginnig of the experiment,For this purpose, an acrylic pipe line has placed on the a bath-tub surface. Acrylic pipe line had holed for lekage and then burried in the soil. Then the experiments has been done with radioisotope and dye tracers. At the second part of the experiment, a lekage point has been created with the same diameter acrylic pipe line. Then the leakage ratio in the minute is calculated. For the dye tracer applications, Sodium Carbonate was used. Because, it has white colour which has good contrast on the soil. Furthermore relative humidty determination has been done for the conventional tracer application. Moreover, humidity tracers are seen on the soil like as dye tracer. IX So, four different techniques have been applied for determination of leakage place experiments. These are, radioactive tracer technique, relative humidity evaluation., humidity tracers and dye tracers techniques. The results of these are compared each other and has been shown that the most sensitive techniques is radiotracer technique.
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Sosyal Bilimler Enstitüsü, 1997
Anahtar kelimeler
Kaçak tayini, Nükleer enerji, Radyoaktif izleyiciler, Leak detection, Nuclear energy, Radioactive tracers