Argon National Laboratory, Env Ass. Henriksen T, Maillie D Radiation and health. Hrichi H, Baccouche S, Belgaied J Evaluation of radiological impacts of tenorm in the tunisian petroleum industry. Misdaq MA, Elharti A A new method for evaluating alpha- and beta-dose rates in various drinking water samples.
9. Uranium, thorium, and their daughters - Very Short Introductions
Misdaq MA, Ouabi H, Merzouki A Analysis of radon, uranium and thorium in potable waters: dose to adult members of the moroccan urban population. Guogang J, Jing J Determination of radium isotope environmental samples by gamma spectrometry, liquid scintillation counting and alpha spectrometry: a review of analytical methodology. Misdaq MA, Satif C A new calculational method adapted to the experimental conditions for determining thorium and uranium contents in geological samples. Misdaq MA, AitNouh F, Bourzik W The influence of the soil and plant natures and pollution on the radon and thoron alpha-activities inside various herbal infusions by using solid state nuclear track detectors.
ICRP Dose coefficients for intakes of radionuclides by workers. ICRP Publication Annals of the ICRP 24 4. These four chains of consecutive parent and daughter nuclei begin and end among elements with atomic numbers higher than 81, which is the atomic weight of thallium; the members of each set are genetically related by alpha and beta decay.
Three of the sets, the thorium series , uranium series , and actinium series , called natural or classical series, are headed by naturally occurring species of unstable nuclei that have half-lives comparable to the age of the elements. By these three radioactive series had been fully delineated. The fourth set, the neptunium series , is headed by neptunium, which has a half-life of 2,, years. Its members are produced artificially by nuclear reactions and do not occur naturally; all their half-lives are short compared with the age of the elements.
Because the two pertinent decay processes result either in no change or in a change of four units in the mass number , the mass numbers of all the members of each series are divisible by four, with a constant remainder.
The thorium series begins with thorium and ends with the stable nuclide lead The neptunium series is named for its longest-lived member, neptunium; it ends with bismuth The uranium series begins with uranium and ends with lead The actinium series, named for its first-discovered member, actinium, begins with uranium and ends with lead Alpha decay , symbolized by a larger arrow in the accompanying diagrams, involves the ejection from an unstable nucleus of a particle composed of two protons and two neutrons.
Thus alpha emission lowers the atomic number number of protons by two units, the neutron number by two units, and the mass number total of neutrons and protons by four units.
Uranium decays by alpha emission into thorium, which itself decays by beta emission to protactinium, which decays by beta emission to uranium, and so on. After several more alpha and beta decays, the series ends with the stable isotope lead Uranium emits alpha particles which are less penetrating than other forms of radiation, and weak gamma rays As long as it remains outside the body, uranium poses little health hazard mainly from the gamma-rays.
If inhaled or ingested, however, its radioactivity poses increased risks of lung cancer and bone cancer. Uranium is also chemically toxic at high concentrations and can cause damage to internal organs, notably the kidneys. Animal studies suggest that uranium may affect reproduction, the developing fetus,  and increase the risk of leukemia and soft tissue cancers.
The property of uranium important for nuclear weapons and nuclear power is its ability to fission, or split into two lighter fragments when bombarded with neutrons releasing energy in the process. Of the naturally-occuring uranium isotopes, only uranium can sustain a chain reaction— a reaction in which each fission produces enough neutrons to trigger another, so that the fission process is maintained without any external source of neutrons.
Traditionally, uranium has been extracted from open-pits and underground mines. In the past decade, alternative techniques such in-situ leach mining, in which solutions are injected into underground deposits to dissolve uranium, have become more widely used. Most mines in the U. The milling refining process extracts uranium oxide U 3 O 8 from ore to form yellowcake, a yellow or brown powder that contains about 90 percent uranium oxide.
In-situ leach mining leaves the unusable portion in the ground, it does not generate this form of waste. The total volume of mill tailings generated in the U.
NIOSHTIC-2 Publications Search
Moreover, the half-lives of the principal radioactive components of mill tailings, thorium and radium are long, being about 75, years and 1, years respectively. The most serious health hazard associated with uranium mining is lung cancer due to inhaling uranium decay products.
- Uranium's Daughters: Transmutation | Uranium: Twisting the Dragon's Tail | PBS LearningMedia.
- The Early Evolutionary History of Planktonic Foraminifera.
- A long Radioactive Lineage;
- Fat: A Cultural History of Obesity.
Uranium mill tailings contain radioactive materials, notably radium, and heavy metals e. Mining and milling operations in the U. For example, nearly one third of all mill tailings from abandoned mill operations are on lands of the Navajo nation alone.
Others continue to suffer the effects of land and water contamination due to seepage and spills from tailings piles. Uranium is generally used in reactors in the form of uranium dioxide UO 2 or uranium metal; nuclear weapons use the metallic form. Production of uranium dioxide or metal requires chemical processing of yellowcake. Further, most civilian and many military reactors require uranium that has a higher proportion of uranium than present in natural uranium.
Related Uranium Daughter
Copyright 2019 - All Right Reserved