Interesting Facts about Uranium
Certain uranium minerals have been know to man since times immemorial. Legends were told about their inexplicable influence upon a man, and sometimes they received the relevant names: «Harmful stone», «Wolf stone». However, despite this, some uranium compounds were used as dyeing agents and moreover even in medicine in the form of radon baths (radon is a gaseous product of radium decay — a grandson of uranium. Radium in its turn was applied at a very early stage in medicine and scientific research). Some compounds of radioactive elements were used for military applications as early as in the First World War. They were mainly used in instrument engineering to manufacture fluorescent paints for gauge dials. The main consumer of fluorescent paints was the Navy.
In the economy depleted uranium is used to manufacture airplane compensation weights and radiation barriers for medical radiotherapeutic equipment. Depleted uranium, due to its unique properties, may be used to manufacture shipping containers for transportation of radioactive cargo and nuclear waste, and items of reliable biological shielding (for example, protective shields).
Highly sensitive devices based on radioactive isotopes allow to perform exploration of minerals. Radiation engineering develops devices whose operation is also based on the use of radioactive isotopes. These are used to give substances new properties, to receive information on qualitative and quantitative parameters of materials and products (for example, gamma-flaw detectors, gamma therapeutic devices, radioactive devices using the principles of tagged compounds for clinical use, isotopic needles, grains for injection into tissues and cavities of an organism, isotope injections etc.). Also, spontaneous uranium nuclear fission may be used to calculate the age of minerals (uranium isotopes are contained in many rocks). In geology, there is even a special term «uranium clock».
Uranium as an element was named after Uranus, the seventh farthest from the Sun giant planet, which had been discovered in 1781 by William Herschel not long before the discovery of uranium. Uranum translates from the Ancient Greek as the «Sky». In mythology Uranus is the god of the sky. One may say that Uranus the god, the farther of 45 children, in the scientist’s imagination was some sort of a «factory» producing offsprings. In nuclear engineering the role of such factory is played by the nuclear reactor — a true factory of new elements and isotopes of the periodic table (fission of atomic nucleus produces almost all elements with mass from 70 to 160.
1 kg of low-enriched uranium U-235 used to produce nuclear fuel upon full nuclear fission releases energy equivalent to burning of approximately 100 tons of high quality coal or 60 tons of oil.
Limits of ionizing radiation: 1 MSv per year for general population and 20 MSv per year on average for five years for persons working in a radiation environment (Radiation Safety Norms 99).
A human body always contains radioactive nuclides of the earth origin which arrive through respiratory system and digestive organs. Formation of internal irradiation dose is mostly accounted for by 40╩, 87Rb, and nuclides of 238U and 232Th fission chains. A man is used to living with natural background radioactive irradiation which amounts per year to 15 micro-roentgen per hour or 130 mRem (rem — is a biological Roentgen equivalent). The annual radiation exposure of population 5 times exceeds the background exposure which includes:
- 34% of medical examination and treatment;
- 22% of natural background;
- 43% of radon decay daughters;
- 0.7% of nuclear test results;
- 0.3% of results of operation of NPPs and other sources of thermal power.