الفهرس 
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Abstract
Uranium is the fuel for about 1000 nuclear reactors of various kinds that exist in the world. These reactors produce electricity, nuclear and thermo nuclear weapons, In addition to the natural uranium, uranium is discharged into the environment due to mining activities, using special military weapons and liquid and gaseous effluents from nuclear facilities.
In the radiochemical equilibrium, it consists of the isotopes 234U, 235U and 238U with the natural activity ratio of 1:0.0462:1, corresponding to amass ratio of 0.0054:0.711:99.2836 percent.
All of these three nuclides are alpha-emitters. from nuclear facilities, additional amounts of uranium are discharged into the environment. In effluents from nuclear facilities ,the ratios of uranium isotopes differ very much .To be able to compare them with that from natural background,
Study of natural radiation background and exposure of human beings are of great importance, not only for practical reasons but also for radiological impact of nuclear activities , It is necessary to determine the baseline of natural radiation and radioactivity so as to distinguish man- made contamination in time and take appropriate measures to protect the environment. Secondly, the accumulation of information on natural radiation is of great value for drawing up rules and regulations on radiation protection standards. Thirdly, natural radiation is the source of exposure of human being: studies of the dose from natural radiation and its effects on health could advance the understanding of radiation damage. Lastly, some natural radionuclides are trace elements, which play important roles in the fields of meteorology, hydrology, geology and astronomy
The main objective of the present study is to determine the uranium isotopes 234U, 235U,238U in the different samples matrices in the environment by using destructive assay alpha spectrometry and non destructive assay gamma spectrometry.