• NUCLEAR REGULATORY COMMISSION

    Some of the sites formerly used for processing thorium and uranium are known today to be contaminated with residual radioactive materials. Some are currently covered by URC licenses. Others were once licensed, but the licenses to possess and use material have expired.

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  • 16 Big Thorium Reactor Pros and Cons –

    A thorium reactor is a form of nuclear energy, proposed for use as a molten salt reactor. It is fueled by the uranium233 isotope that is taken from the element thorium. Thorium is weakly radioactive, has a high melting point, and is available with more abundance than uranium as an element.

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  • Effective Radium Contents of Some Ores and Dose Rates

    From Eq. (7) the thorium to uranium ratio is given by : R= ((p(l) S(l)/A(l)J23. (8) The critical angles (Įc) of the CR39 and LR115 detectors depend on the alphaparticle energy and the residual thickness of the detector. For the optimum track contrast, the present etch track conditions are :

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  • The First Thorium Salt Reactors in Over 40 Years Were Just ...

    Aug 25, 2017· Thorium doesn't – its isotope Th232 requires another source of neutrons to bombard its nucleus, at which point it transmutes into an isotope of uranium called U233. A significant advantage of using thorium over uranium is it doesn't produce the same kinds of heavy isotopes, meaning its waste is considerably less toxic over long time scales.

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  • Derivation of Guidelines for Uranium Residual Radioactive ...

    remaining residual radioactive materials at the site. The primary radionuclides of concern in these remaining materials are expected to be radium226 and, to a lesser extent, natural uranium and thoriuim. The DOE has established generic cleanup guidelines for radium and thorium in

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  • SOIL DECOMMISSIONING PLAN New Mexico

    Soil Decommissioning Plan USA, CANADA, UK AND WORLDWIDE LIST OF ACRONYMS AND ABBREVIATIONS (CONT'D) RESRAD RESidual RADiation dose modeling software RoC Radionuclide of Concern RSO Radiation Safety Officer Th thorium TEDE Total Effective Dose Equivalent U uranium yr year

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  • Samples Containing Thorium or Uranium

    Thoriumbearing minerals are widespread, but generally in small amounts. Monazite is the principal source of Th. Uranium is estimated to be present in the earth's crust at about 4 ppm and occurs combined with silicates, phosphates, and zirconates.

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  • HEALTH ENVIRONMENTAL PROTECTION STANDARDS FOR .

    Uranium Processing Sites § Applicability. This subpart applies to the control of residual radioactive material at designated processing or depository sites under section 108 of the Uranium Mill Tailings Radiation Control Act of 1978 (henceforth designated "the Act"), and to restoration of such sites following any use of subsurface

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  • Thorium Geology and Mineralogy of Occurrences

    limestone averages about 2 ppm. Shale contains 1015 ppm Th; small amounts of thorium may adsorb to clay particles during weathering. Bauxite contains up to 50 ppm; this material is typically the residual weathering of alkali rocks. Although it will be demonstrated below that thorium reserves are associated with phosphorusenriched rocks,

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  • Is thorium a cleaner, safer and cheaper alternative to ...

    Jul 12, 2016· Residual materials from thoriumbased nuclear power lose their radioactivity faster than residual materials from uraniumbased nuclear fuels. In the short term, however, thorium's residual materials emit stronger radiation and this increases the cost of the immediate handling.

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  • CARBONATITE DEPOSITS (MODEL 10; Singer, 1986a)

    Most carbonatite deposits are likely to be mined on a large scale in open pit mines. Potential impacts include radioactivity from uranium and (or) thorium in waste rock or sediment; dust from mining activities; acid and (or) metalcontaminated drainage from pyriterich carbonatites; and possible water contamination from spillage or leakage

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  • Introduction Thorium Energy

    The element thorium was discovered in 1828. More than a 100 years later, in 1941, its potential as an energy source was proved. Thorium is estimated to be three to four times more abundant than uranium in the Earth's crust and it is one of the most energy dense elements found in nature.

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  • Uranium Radiation Properties

    Uranium mill tailings are the residual waste from the process of uranium extraction from the uranium ore. Since only uranium is extracted, all other members of the uranium decay chains remain in the tailings at their original activities.

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  • Questions and Answers from the EPA Radionuclides Rule ...

    Ion exchange is effective for uranium removal in the pH range of Ion exchange at pH for uranium removal was tested in a Chimney Hill, TX pilot study and was found to be equally effective as pH 8, for 27,000 BV run lengths. It is not necessary to adjust the pH to

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  • URANIUM / THORIUM

    Potassium is measured directly from the 1460 keV gammaray photons emitted by K40, whereas uranium and thorium are measured indirectly from gammaray photons emitted by daughter products (Bi 214 for uranium and Tl 208 for thorium).

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  • Use of Thorium for Transmutation of Plutonium and Minor ...

    production of Pu from uranium in the fuel reduces the effectiveness of Pu destruction. In order to accelerate Pu and MA destruction, the amount of uranium loaded into the core must be minimised. Two options seem to be promising in that respect – fertilefree and thorium based fuels.

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  • Radiotoxicity and Residual Energy Release of Spent Uranium ...

    A computational comparison is made of the radiotoxicity and residual energy release of spent uranium–plutonium and thorium–uranium nuclear fuel during longterm storage. The contribution of the most significant nuclides, whose primary extraction and transmutation make it possible to decrease energy release and radiotoxicity of the remaining stored wastes, is determined. 2 figures, 4 references.

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  • Uranium Radiation Properties

    Uranium mill tailings are the residual waste from the process of uranium extraction from the uranium ore. Since only uranium is extracted, all other members of the uranium decay chains remain in the tailings at their original activities.

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  • Thorium – Helian Unbound

    Thorium by itself cannot power a nuclear reactor. It must first be converted into the isotope uranium 233 via absorption of a neutron. Natural uranium, on the other hand, can be used directly in reactors, because percent of it consists of the fissile isotope uranium 235.

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  • SYSTEMS FOR CLASSIFICATION OF LOWLEVEL .

    under a license from NRC, while residual radioactive material is waste material present at inactive uranium processing sites designated in the Act. Residual Radioactive Material (UMTRCA SiteSpecific, Inactive Uranium or Thorium Mills) "Residual radioactive material" is .

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