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Sample records for ahwr-the indian thorium

  1. Indian advanced heavy water reactor for thorium utilisation and nuclear data requirements and status

    International Nuclear Information System (INIS)

    BARC is embarking on thorium utilisation program in a concerted and consistent manner to achieve all round capabilities in the entire Thorium cycle under the Advanced Heavy Water Reactor (AHWR) development program. Upgrading our nuclear data capability for thorium cycle is one of the main tasks of this program. This paper gives a brief overview of the physics design features of the AHWR. The basic starting point of the analysis has been the lattice simulation of the fuel cluster employing the WIMS-D4 code package with 1986 version of 69 group library. For the analysis of thorium cycle, the present multi group version contains the three major isotopes viz., 232Th, 233U and 233Pa. To correctly evaluate the fuel cycle we require many more isotopes of the Th burnup chain. With the help of NDS, IAEA, many other isotopes of interest in AHWR, actinides in the thorium burnup chain, burnable absorbers, etc., were generated. Some of them were added to the WIMS-D4 library and the results are discussed. The WIMS-D4 library is also being updated as part of the IAEA coordinated research project on Final Stage of WLUP with international cooperation. India is also taking part in CRP. The evaluation of AHWR lattice with this new library is presented. Some comments regarding the fission product data being used in WIMS libraries are given, which are tuned to U-Pu cycles. The measurements for 233U are rather old. Measurements in high energies are also very sparse. More attention by nuclear data community is required in this regard as well. India has also begun a modest program to assess the ADS concepts, with the aim of employing thermal reactor systems, such as AHWR. A one way coupled booster reactor concept is being analysed with available code systems and nuclear data. A brief summary of this concept is also being discussed in this paper. A general survey on the quality of the evaluated nuclear data of the major and minor isotopes of thorium cycle is also given. A major

  2. Thorium

    Science.gov (United States)

    Wickleder, Mathias S.; Fourest, Blandine; Dorhout, Peter K.

    In 1815 Berzelius analyzed a rare mineral from the Falun district. He assumed that the mineral contained a new element, which he named thorium after the ancient Scandinavian god of thunder and weather, Thor (Weeks and Leicester, 1968).

  3. Thorium

    International Nuclear Information System (INIS)

    General mineralogical-geochemical and analytical characteristics of thorium are presented. It is stressed that the main trend in the development of analytical methods for determining Th in mineral raw material is the use of physical methods of the analysis. To separate Th from RE, Zr, U being its permanent companions, precipitation, extraction and ion exchange are used. Principal methods of geologic samples dissolution are considered. Some techniques of radiometric, emanation, (by thoron), neutron activation, fluorescence X-ray spectral, spectrographic, gravimetric, photometric (with arsenazo 3) thorium determinations are described

  4. Utilisation of thorium in reactors

    Science.gov (United States)

    Anantharaman, K.; Shivakumar, V.; Saha, D.

    2008-12-01

    India's nuclear programme envisages a large-scale utilisation of thorium, as it has limited deposits of uranium but vast deposits of thorium. The large-scale utilisation of thorium requires the adoption of closed fuel cycle. The stable nature of thoria and the radiological issues associated with thoria poses challenges in the adoption of a closed fuel cycle. A thorium fuel based Advanced Heavy Water Reactor (AHWR) is being planned to provide impetus to development of technologies for the closed thorium fuel cycle. Thoria fuel has been loaded in Indian reactors and test irradiations have been carried out with (Th-Pu) MOX fuel. Irradiated thorium assemblies have been reprocessed and the separated 233U fuel has been used for test reactor KAMINI. The paper highlights the Indian experience with the use of thorium and brings out various issues associated with the thorium cycle.

  5. Thorium 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The Roskill report on thorium gives facts and figures on the occurrence, production, consumption and end-uses and international trade. Thorium deposits, resources and the production of thorium minerals are reviewed. International trade statistics are given. (author).

  6. Scientometric dimensions of thorium research in India

    OpenAIRE

    Kademani, B. S.; Vijai, Kumar; Anil, Sagar; Anil, Kumar; Lalit, Mohan; Surwase, Ganesh

    2006-01-01

    This paper attempts to provide detailed quantitative analysis of Indian contributions on thorium in terms of publications output as per International Nuclear information System database during 1970-2004. A total of 2399 papers were published by the Indian scientists in the field of thorium. There were only nine publications in 1970. Thereafter, a steady growth was observed except for the period 1983-1985. The highest papers (188) were! published in the year 2000. USA with 8049 (28.05 per c...

  7. PRODUCTION OF THORIUM FLUORIDE

    Science.gov (United States)

    Zachariasen, W.H.

    1959-08-11

    A process is presented for producing anhydrous thorium fluoride comprising the step of contacting a saturated aqueous solution of thorium nitrate with an aqueous solution of hydrofluoric acid having a concentration of about 45 to 50% by weight at a temperature above 70 deg C whereby anhydrous thorium fluoride precipitates.

  8. Uranium and thorium

    International Nuclear Information System (INIS)

    Present article is devoted to uranium and thorium content in fluorite. In order to obtain the comprehensive view on uranium and thorium distribution in fluorite 100 fluorite samples of various geologic deposits and ores of Kazakhstan, Uzbekistan, Tajikistan and some geologic deposits of Russia were studied. The uranium and thorium content in fluorite of geologic deposits of various mineralogical and genetic type was defined.

  9. Thorium Energy Futures

    OpenAIRE

    Peggs, S.; Horak, W.; Roser, T.; Ashley, V.B.; Ashworth, R.F.; Barlow, Roger; Cywinski, R.; Seviour, Rebecca; Biarrotte, J.-L.; Henderson, S.; Hutton, A; Kelly, J; Lindroos, M.; McIntyre, P. M.; Norlin, A.

    2012-01-01

    The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than...

  10. Thorium Energy Futures

    Energy Technology Data Exchange (ETDEWEB)

    Peggs, Stephen; Roser, Thomas; Parks, G; Lindroos, Mats; Seviour, Rebecca; Henderson, Stuart; Barlow, R; Cywinski, R; Biarrote, J -L; Norlin, A; Ashley, V; Ashworth, R; Hutton, Andrew; Owen, H; McIntyre, Peter

    2012-07-01

    The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options - liquid or solid, with or without an accelerator - can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice.

  11. Thorium in human tissues

    International Nuclear Information System (INIS)

    The human tissue contents of natural alpha-emitting isotopes of thorium (228Th, 230Th, and 232Th) were determined in six sets of samples from Colorado and two lung samples from New York. Lung, lymph nodes from lung, liver, kidney, spleen, and bone were obtained at autopsy, and radiochemical analyses were made. Thorium-230 and 232Th are distributed similarly in the body, with major amounts present in bone (60%), followed by lung (20%) and lymph nodes (6%). Concentration decreased in the order lymph nodes > lung > bone > liver, kidney, and spleen. Thorium-228 is found primarily in bone (95%), and concentration decreases in the order lymph nodes > bone > lung > liver, kidney, and spleen. For all isotopes the median ratio of concentration in lymph nodes to lung was about 15. Thorium-230 was significantly increased in lung and skeleton samples from an underground hard-rock miner

  12. Thorium ore deposits

    International Nuclear Information System (INIS)

    The main occurences of the thorium minerals of the Argentine Republic which have not been exploited, due to their reduced volume, are described. The thoriferous deposits have three genetic types: pegmatitic, hydrothermal and detritic, being the most common minerals: monazite, thorite and thorogummite. The most important thorium accumulations are located in Salta, being of less importance those of Cordoba, Jujuy and San Juan. (M.E.L.)

  13. Thorium utilization in power reactors

    International Nuclear Information System (INIS)

    In this work the recent (prior to Aug, 1976) literature on thorium utilization is reviewed briefly and the available information is updated. After reviewing the nuclear properties relevant to the thorium fuel cycle we describe briefly the reactor systems that have been proposed using thorium as a fertile material. (author)

  14. PLUTONIUM-THORIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  15. Determination of uranium and thorium in monazite bearing sand by gamma ray spectrometry

    International Nuclear Information System (INIS)

    Monazite is one of the most important natural geological mineral due to the presence of heavy metals, rare earth and natural radioactive elements. Monazite is also an important ore for thorium, lanthanum, and cerium. It is very important to assess the concentration of uranium and thorium in various monazite samples observed in Indian coasts and their relative abundance. In addition to thorium, availability of uranium in monazite is also of interest because of an alternate source for the uranium fuel cycle operation going on in our country. The relative abundance of uranium in monazite bearing sands can be represented by the activity ratio of uranium to thorium in the samples. In the present study an attempt has been made to estimate the activity ratios of uranium to thorium in some of the monazite bearing beach sands collected from our coastal regions by using high resolution gamma ray spectrometry techniques

  16. Thorium is an ultimate source of energy

    OpenAIRE

    Kim, HungGeun; Lee, Sangcheol

    2013-01-01

    This article is written for readers to help the understanding of thorium as an alternative source of nuclear energy. Thorium (Thorium) can be applied for reactor fuels and thorium energy development such as ADSR; Accelerator Driven Subcritical Reactor. This particle explains the thorium as a possible choice to replace of uranium to supply enormous energy could be the energy source. A Korean article published in "Science Times" in South Korea. The article is based on an interview ...

  17. Energy from thorium—An Indian perspective

    Indian Academy of Sciences (India)

    Umasankari Kannan; P D Krishnani

    2013-10-01

    Nuclear energy as a sustainable resource in India has been very clearly formulated in the three stage nuclear programme. The role of thorium as a potential fuel in the third stage of this programme has also been elucidated. With this aim there have been pioneering research efforts in all aspects of the thorium fuel cycle. Thorium being fertile and not accompanied by the fissile species requires the use of a fissile topping. There have been several studies in India on the use of thorium in different reactor systems from thermal to intermediate and fast spectrum, molten salt reactors, high temperature reactors, compact nuclear power packs and even Subcritical systems. In this paper, we present some of the research studies on use of thorium in thermal reactor systems. We give an overview of the neutronic properties of thorium and the bred fissile material and then proceed to show the performance potential in different reactor systems. We also present the innovative Indian reactor designs which utilize thorium, namely the Advanced Heavy Water Reactor (AHWR) and the Indian High Temperature Reactors.

  18. Sustainability: role of thorium

    International Nuclear Information System (INIS)

    The task to renew the world's energy infrastructure, where fossil fuels account for 80% of supply, is enormous. The two carbon neutral energy sources - renewable and nuclear - should be the base of the world's future energy mix. Nuclear, however, suffers from a bad public opinion and lack of government support in many parts of the world. We can conclude that the world needs an 'on demand' energy source that is affordable, clean, safe and scalable. Thorium energy could be that energy source. It is the most energy dense solution we know, fitting well to the modular and size-constrained requirements of an urbanizing world. No part of society can create a sustainable world on their own and markets are too slow to drive transformational changes. We need new partnerships between governments, business, civil society and academia where each part is delivering on their specific responsibilities and roles

  19. Thorium nuclear fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Tae Yoon; Do, Jae Bum; Choi, Yoon Dong; Park, Kyoung Kyum; Choi, In Kyu; Lee, Jae Won; Song, Woong Sup; Kim, Heong Woo

    1998-03-01

    Since thorium produces relatively small amount of TRU elements after irradiation in the reactor, it is considered one of possible media to mix with the elements to be transmuted. Both solid and molten-salt thorium fuel cycles were investigated. Transmutation concepts being studied involved fast breeder reactor, accelerator-driven subcritical reactor, and energy amplifier with thorium. Long-lived radionuclides, especially TRU elements, could be separated from spent fuel by a pyrochemical process which is evaluated to be proliferation resistance. Pyrochemical processes of IFR, MSRE and ATW were reviewed and evaluated in detail, regarding technological feasibility, compatibility of thorium with TRU, proliferation resistance, their economy and safety. (author). 26 refs., 22 figs

  20. Speeding-up Thorium decay

    CERN Document Server

    Cardone, F; Petrucci, A

    2007-01-01

    We show that cavitation of a solution of thorium-228 in water induces its transformation at a rate 10000 times faster than the natural radioactive decay would do. This result agrees with the alteration of the secular equilibrium of thorium-234 obtained by a Russian team via explosion of titanium foils in water and solutions. These evidences further support some preliminary clues for the possibility of piezonuclear reactions (namely nuclear reactions induced by pressure waves) obtained in the last ten years.

  1. Advanced nuclear reactor systems - an Indian perspective

    International Nuclear Information System (INIS)

    The Indian nuclear power programme envisages use of closed nuclear fuel cycle and thorium utilisation as its mainstay for its sustainable growth. The current levels of deployment of nuclear energy in India need to be multiplied nearly hundred fold to reach levels of electricity generation that would facilitate the country to achieve energy independence as well as a developed status. The Indian thorium based nuclear energy systems are being developed to achieve sustainability in respect of fuel resource along with enhanced safety and reduced waste generation. Advanced Heavy Water Reactor and its variants have been designed to meet these objectives. The Indian High Temperature Reactor programme also envisages use of thorium-based fuel with advanced levels of passive safety features. (author)

  2. Determination of thorium in plutonium-thorium oxides and carbides

    International Nuclear Information System (INIS)

    Thorium is determined in (PuTh)C and (PuTh)O2 by complexometric titration with ethylenediaminetetraacetic acid (EDTA) following separation on anion-exchange resin. Carbides are first oxidized by ignition in air at about 8000C. Oxide or oxidized carbide samples are dissolved in acids by the sealed-reflux technique or by heating in beakers. The plutonium is selectively sorbed from the 12M hydrochloric acid solution of the fuel on a Bio-Rad AG1-X2 anion-exchange resin column, and the eluted thorium is titrated with EDTA using xylenol orange as the indicator. The average recovery of thorium in 20 samples is 99.98% with a relative standard deviation of 0.07%

  3. Thorium Energy for the World

    CERN Document Server

    Revol, Jean-Pierre; Bourquin, Maurice; Kadi, Yacine; Lillestol, Egil; De Mestral, Jean-Christophe; Samec, Karel

    2016-01-01

    The Thorium Energy Conference (ThEC13) gathered some of the world’s leading experts on thorium technologies to review the possibility of destroying nuclear waste in the short term, and replacing the uranium fuel cycle in nuclear systems with the thorium fuel cycle in the long term. The latter would provide abundant, reliable and safe energy with no CO2 production, no air pollution, and minimal waste production. The participants, representatives of 30 countries, included Carlo Rubbia, Nobel Prize Laureate in physics and inventor of the Energy Amplifier; Jack Steinberger, Nobel Prize Laureate in physics; Hans Blix, former Director General of the International Atomic Energy Agency (IAEA); Rolf Heuer, Director General of CERN; Pascal Couchepin, former President of the Swiss Confederation; and Claude Haegi, President of the FEDRE, to name just a few. The ThEC13 proceedings are a source of reference on the use of thorium for energy generation. They offer detailed technical reviews of the status of thorium energy ...

  4. The economics of thorium fuel cycles

    International Nuclear Information System (INIS)

    The individual cost components and the total fuel cycle costs for natural uranium and thorium fuel cycles are discussed. The thorium cycles are initiated by using either enriched uranium or plutonium. Subsequent thorium cycles utilize recycled uranium-233 and, where necessary, either uranium-235 or plutonium as topping. A calculation is performed to establish the economic conditions under which thorium cycles are economically attractive. (auth)

  5. Role of thorium in ensuring long term energy security to India

    International Nuclear Information System (INIS)

    Role of nuclear power in ensuring energy security to the world is inevitable due to a) dwindling fossil fuel resources and b) need for minimising green house gas emission that poses the risk of global climate change. India, keeping in mind its limited uranium and vast thorium resources, is pursuing a three stage nuclear power programme. The first stage is based on reactors that use uranium as fuel. It comprises of the indigenous Pressurised Heavy Water Reactors using natural uranium as fuel and light water reactors that employ enriched uranium as fuel and are to be set up in technical collaboration with other countries. The second stage is based on fast breeder reactors that employ plutonium derived from reprocessing of spent fuel from the first stage reactors. The third stage envisages reactors which will employ thorium based fuel after its irradiation in the second stage reactors. This programme is sequential in nature and has an ultimate objective of securing long term energy security to India through judicial use of its thorium resources. Thorium based reactors offer advantages in terms of better neutronic characteristics of thorium, it being better fertile host for plutonium disposition and better thermo-mechanical properties and slower fuel deterioration of thorium oxide. It is planned to introduce thorium in the Indian Nuclear Power Programme after sufficient (about 200 GWe) capacity build-up in the second stage. DAE is a global leader in the development of the entire thorium fuel cycle. It has a mature technology for extraction of thorium and preparation of thoria pellets. It has long back carried out irradiation of thoria pellets in its research reactors and also in PHWRs, post irradiation examination and reprocessing of irradiated thoria, fabrication of 233U based fuel. It has KAMINI - the world's only operating reactor employing 233U as fuel. An Advanced Heavy Water Reactor (AHWR) has been designed as a technology demonstrator for large scale utilisation

  6. Assessment of Thorium Analysis Methods

    International Nuclear Information System (INIS)

    The Assessment of thorium analytical methods for mixture power fuel consisting of titrimetry, X-ray flouresence spectrometry, UV-VIS spectrometry, alpha spectrometry, emission spectrography, polarography, chromatography (HPLC) and neutron activation were carried out. It can be concluded that analytical methods which have high accuracy (deviation standard < 3%) were; titrimetry neutron activation analysis and UV-VIS spectrometry; whereas with low accuracy method (deviation standard 3-10%) were; alpha spectrometry and emission spectrography. Ore samples can be analyzed by X-ray flourescnce spectrometry, neutron activation analysis, UV-VIS spectrometry, emission spectrography, chromatography and alpha spectometry. Concentrated samples can be analyzed by X-ray flourescence spectrometry; simulation samples can be analyzed by titrimetry, polarography and UV-VIS spectrometry, and samples of thorium as minor constituent can be analyzed by neutron activation analysis and alpha spectrometry. Thorium purity (impurities element in thorium samples) can be analyzed by emission spectography. Considering interference aspects, in general analytical methods without molecule reaction are better than those involving molecule reactions (author). 19 refs., 1 tabs

  7. Thorium in occupationally exposed men.

    Energy Technology Data Exchange (ETDEWEB)

    Stehney, A. F.

    1999-02-24

    Higher than environmental levels of {sup 232}Th have been found in autopsy samples of lungs and other organs from four former employees of a thorium refinery. Working periods of the subjects ranged from 3 to 24 years, and times from end of work to death ranged from 6 to 31 years. Examination of the distribution of thorium among the organs revealed poor agreement with the distribution calculated from the dosimetric models in Publication 30 of the International Commission on Radioprotection (ICRP). Concentrations in the lungs relative to pulmonary lymph nodes, bone or liver were much higher than calculated from the model for class Y thorium and the exposure histories of the workers. Much better agreement was found with more recently proposed models in Publications 68 and 69 of the ICRP. Radiation doses estimated from the amounts of thorium in the autopsy samples were compatible with health studies that found no significant difference in mortality from that of the general population of men in the US.

  8. Radiological significance of thorium processing in manufacturing

    International Nuclear Information System (INIS)

    The study of thorium processing in manufacturing comprised monitoring programs at a plant where thorium dioxide was in use and another where the use of thorium nitrate had been discontinued. The measurements of the solubility in simulated lung fluid proved that both materials belonged in the Y Class with dissolution half-times greater than 500 days. Bioassay measurements of 20 subjects from both facilities proved that in vitro monitoring methods, urine, feces, hair and nails analysis were not sufficient indicators of thorium uptake. In vivo monitoring by phoswich and large sodium iodide detectors were proven to be good methods of determining thorium lung burdens. The thoron in breath technique was shown to have a lower limit of sensitivity than lung counting, however, due to lack of information regarding the thoron escape rate from the thorium particles in the lungs the method is not as accurate as lung counting. Two subjects at the thorium dioxide facility had lung burdens of 21+- 16 Bq and 29+- 24 Bq Th232 and one at the thorium nitrate facility had a lung burden of 37+- 13 Bq. Improvements in the procedures and use of a glove box were among the recommendations to reduce the inhalation of thorium by workers at the thorium dioxide facility. Decontamination of several rooms at the thorium nitrate facility and sealing of the walls and floors were recommended in order to reduce the escape of thoron gas into the room air. The risk to non Atomic Radiation Workers was primarily due to thoron daughters in air while gamma radiation and thorium in air were less important. Conversely, at the thorium dioxide facility the inhalation of thorium in air was the most significant exposure pathway

  9. Abundant thorium as an alternative nuclear fuel

    International Nuclear Information System (INIS)

    It has long been known that thorium-232 is a fertile radioactive material that can produce energy in nuclear reactors for conversion to electricity. Thorium-232 is well suited to a variety of reactor types including molten fluoride salt designs, heavy water CANDU configurations, and helium-cooled TRISO-fueled systems. Among contentious commercial nuclear power issues are the questions of what to do with long-lived radioactive waste and how to minimize weapon proliferation dangers. The substitution of thorium for uranium as fuel in nuclear reactors has significant potential for minimizing both problems. Thorium is three times more abundant in nature than uranium. Whereas uranium has to be imported, there is enough thorium in the United States alone to provide adequate grid power for many centuries. A well-designed thorium reactor could produce electricity less expensively than a next-generation coal-fired plant or a current-generation uranium-fueled nuclear reactor. Importantly, thorium reactors produce substantially less long-lived radioactive waste than uranium reactors. Thorium-fueled reactors with molten salt configurations and very high temperature thorium-based TRISO-fueled reactors are both recommended for priority Generation IV funding in the 2030 time frame. - Highlights: • Thorium is an abundant nuclear fuel that is well suited to three advanced reactor configurations. • Important thorium reactor configurations include molten salt, CANDU, and TRISO systems. • Thorium has important nuclear waste disposal advantages relative to pressurized water reactors. • Thorium as a nuclear fuel has important advantages relative to weapon non-proliferation

  10. Impact of Thorium Capture Cross Section Uncertainty on the Thorium Utilized ADS Reactivity Calculation

    OpenAIRE

    Thanh Mai Vu; Takanori Kitada

    2014-01-01

    Recently, the researches on fast neutron spectrum system utilized thorium fuel are widely conducted. However, the recent thorium cross section libraries are limited compared to uranium cross section libraries. The impact of thorium cross section uncertainty on thorium fuel utilized accelerator driven system (ADS) reactivity calculation is estimated in this study. The uncertainty of the keff caused by 232Th capture cross section of JENDL-4.0 is about 1.3%. The uncertainty of JENDL-4.0 is neede...

  11. Thorium fuel cycle - Potential benefits and challenges

    International Nuclear Information System (INIS)

    There has been significant interest among Member States in developing advanced and innovative technologies for safe, proliferation resistant and economically efficient nuclear fuel cycles, while minimizing waste and environmental impacts. This publication provides an insight into the reasons for renewed interest in the thorium fuel cycle, different implementation scenarios and options for the thorium cycle and an update of the information base on thorium fuels and fuel cycles. The present TECDOC focuses on the upcoming thorium based reactors, current information base, front and back end issues, including manufacturing and reprocessing of thorium fuels and waste management, proliferation-resistance and economic issues. The concluding chapter summarizes future prospects and recommendations pertaining to thorium fuels and fuel cycles

  12. Antineutrino Monitoring of Thorium Reactors

    CERN Document Server

    Akindele, Oluwatomi A; Norman, Eric B

    2015-01-01

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuels types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring.Thorium molten salt reactors (MSR) breed U-233, that if diverted constitute an IAEA direct use material. The antineutrino spectrum from the fission of U-233 has been determined, the feasibility of detecting the diversion of a significant quantity, 8 kg of U-233, within the IAEA timeliness goal of 30 days has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario at a 25 meter standoff by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos. It was found that the diversion of a signifi...

  13. Thorium and the Third Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dukert, Joseph M.

    1970-01-01

    This booklet discusses energy sources for nuclear power plants. Uranium-235 by itself will not be able to handle the energy needs. The two man-made supplements that can be used for nuclear power plants energy sources are plutonium and uranium-233. Uranium-233 is an isotope that appears as a result of radioactive decay after neutrons have been absorbed in thorium-232. This uranium-233 is called the third fuel.

  14. Health effects of industrial exposure to thorium

    International Nuclear Information System (INIS)

    The objective of this project is to determine the health effects of industrial exposure to thorium and the long-term pattern of deposition of inhaled thorium and its daughter products in human tissues. We obtained the study populations from employment records of the Lindsay Chemical Company and its corporate successors. The company was primarily engaged in the extraction of thorium and rare earth chemicals from monazite ores and in the production of thorium-impregnated mantles for gas lamps. From all available records, which date back to 1925, we have identified 3542 male and 1040 female employees. 1 ref

  15. Thorium-U Recycle Facility (7930)

    Data.gov (United States)

    Federal Laboratory Consortium — The Thorium-U Recycle Facility (7930), along with the Transuranic Processing Facility (7920). comprise the Radiochemical Engineering Development Complex. 7930 is a...

  16. Electrostatic Radionuclide Separation: A New Version of Rutherford's "Thorium Cow".

    Science.gov (United States)

    Eiswirth, Marcus; And Others

    1982-01-01

    Describes three experiments (also useful as demonstrations) using a "thorium cow," a device which concentrates the daughter products from thorium compounds by precipitation on a charged electrode. (JN)

  17. Studies on the preparation of thorium metal sponge from thorium oxalate

    International Nuclear Information System (INIS)

    The results of investigations carried out on the production of high purity thorium metal sponge, starting with thorium oxalate are presented. The flow sheet includes chlorination of thorium oxalate, purification of raw thorium tetrachloride, magnesium reduction of anhydrous thorium tetrachloride, slag metal separation, vacuum distillation for removal of residual MgCl2 and excess magnesium, and consolidation of the metal sponge. Studies have been carried out to investigate the optimum chlorination efficiency and chlorine utilization attainable using different chlorinating agents, and to compare the quality of the sponge obtained with single and double distilled chloride. The overall process efficiency under optimum conditions was 81%. The thorium metal button, prepared from the sponge by arc-melting, analysed : O2 - 847, N2 - 20, C - 179, Mg - 100, Fe - 49, Ni<50, Al - 11, Cr - 7 (expressed in parts per million parts of thorium). The button could be further purified by electron beam melting to improve its ductility. (author)

  18. Utilization of thorium in power reactors

    International Nuclear Information System (INIS)

    The IAEA convened a Panel on the utilization of thorium in power reactors from 14 to 18 June 1965. 45 scientists from 14 countries and two international organizations took part in it. The proceedings of the Panel include 23 survey papers and brief reviews which stress the importance of utilizing thorium. A separate abstract was prepared for each of these papers. Refs, tabs, figs

  19. Thorium and health: state of the art

    International Nuclear Information System (INIS)

    This report reviews data available in the literature on the subject: 'thorium and health'. Thorium is a natural radioactive element of the actinide series. It is widely distributed in the earth's crust and 99% is found as isotope thorium-232. Its various uses are explained by its chemical, physical, and nuclear properties. As a potential nuclear fuel, thorium is still in demonstration in pilot scale reactors. But thorium has already multiple and sometimes unknown industrial uses. Some mass market products are concerned like light bulb. This raises the issue of wastes, and of exposures of workers and public. Environmental exposure via food and drink of the general population is low, where as workers can be exposed to significant doses, especially during ore extraction. Data on bio-monitoring of workers and biokinetic of thorium, in particular those provided by ICRP, are gathered here. Studies on health effects and toxicity of thorium are scarce and mostly old, except outcomes of its previous medical use. Studies on other forms of thorium should be undertaken to provide substantial data on its toxicity. Concerning treatment, Ca-DTPA is the recommended drug even if its efficacy is moderate. LiHOPO molecule shows interesting results in animals, and further research on chelating agents is needed. (authors)

  20. Philosophy of future ready thorium reactor designs

    International Nuclear Information System (INIS)

    Due to modest uranium reserves and abundant thorium resources, thorium fuel cycle and thorium based reactors are very important to India. Over a period of time India has developed expertise in all aspects of thorium utilisation starting from mining, metal extraction, fuel fabrication, irradiation in reactors, reprocessing, and recycling the recovered 233U. In-line with the maturing of these technologies, development of innovative and advanced reactors is being pursued. India is developing technologies for thorium based reactors in many configurations, from light water cooled designs to high temperature liquid metal and molten salt cooled options. A research reactor, KAMINI, based on 233U was commissioned at Indira Gandhi Centre for Atomic Research (IGCAR) in Kalpakkam in 1996. This is the only reactor in the world currently operating with 233U based fuel. Advanced Heavy Water Reactor (AHWR) aims at technology development for industrial scale thorium utilisation. Thorium is also planned to be used in the High Temperature Reactors, which hold promise of producing hydrogen as an alternate energy carrier for transport applications, thus ensuring long term energy security. For long-term sustainability, it is envisaged to take full advantage of the unique characteristics of 233U - thorium fuel cycle, through development and deployment of advanced nuclear energy systems, such as molten salt breeder reactors and accelerator-driven sub-critical systems

  1. Possible types of breeders with thorium cycle

    International Nuclear Information System (INIS)

    Neutronics calculations of simplified homogeneous reactor models show the possibility that metal-fueled LMFBRs and coated particle fueled gas cooled reactors achieve reactor doubling times of around 10 years with the thorium cycle. Three concepts of gas-cooled thorium cycle breeders are discused. (Author)

  2. Possible types of breeders with thorium cycle

    International Nuclear Information System (INIS)

    Neutronics calculations of simplified homogeneous reactor models show the possibility that metal-fueled LMFBRs and coated particle fueled gas cooled reactors achieve doubling times of around 10 years with the thorium cycle. Three concepts of gas-cooled thorium cycle breeders are discussed. (Author)

  3. Thorium: physicochemistry, pathophysiology, risks and prevention

    International Nuclear Information System (INIS)

    A contrast medium containing radioactive thorium (Thorotrast) was widely used in many countries from 1928 to 1950. This compound is associated with the occurrence after several decades of malignant tumors, in particular of the liver. Such tumors are still reported occasionally. The colloidal granules of metallic thorium accumulated in target organs (liver, kidney), subjecting them to high levels of alpha radiation. The reticular deposits of thorium granules can be seen clearly on roentgenograms and should be looked for routinely in patients with a history of injection of a contrast medium before 1950. Removal of the deposits in asymptomatic patients can be beneficial. Thorotrast-associated cancers have received little media coverage, in contrast with a recent case in a scrap metal merchant who took apart the wreck of a Mirage F1 plane with thorium-magnesium alloy parts. The risks related to exposure to thorium and preventive strategies are discussed. (author). 20 refs., 4 tabs

  4. Thorium isotopes in human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Stehney, A.F.; Lucas, H.F.

    1991-12-31

    Concentrations of {sup 232}Th and activity ratios of {sup 228}Th to {sup 232}Th and {sup 230}Th to {sup 232}Th were determined in autopsy samples from five former employees of a thorium refinery. The ranges of {sup 232}Th activity concentrations (mBq g{sup {minus}1}) were 0.17--94 in lungs, 3.9--1210 in pulmonary lymph nodes, 0.14--1.19 in bones, 0.015--0.68 in liver, 0.97--5.8 in spleen, and 0.009--0.068 in kidneys. These concentrations are 10 to 1000 times greater than have been reported for persons not occupationally exposed to Th. In most of the samples, the ratios of {sup 230}Th to {sup 232}Th and {sup 228}Th to {sup 232}Th activity at death of the subject were 0.1--0.2 and 0.2--0.4, respectively. Thorium-228 to {sup 228}Ra activity ratios ({plus_minus} standard errors) of 0.86 {plus_minus} 0.11 in lungs and 1.18 {plus_minus} 0.13 in lymph nodes of one subject were obtained by calculation from ratios of {sup 228}Th to {sup 232}Th.

  5. Pressurized water reactor thorium fuel cycle studies

    International Nuclear Information System (INIS)

    The use of a thorium fuel cycle in a PWR is studied. The thorium has no fissile isotope and a fissile nuclide must be added to the thorium fuel. This nuclide can be uranium 235, plutonium 239 or uranium 233. In this work we have kept the fuel assembly geometry and the control rod system of an usual PWR. Cell calculations showed that the moderation ratio of an usual PWR can be used with uranium 235 and plutonium 239 fuels. But this moderation ratio must be decreased and accordingly the pumping power must be increased in the case of a uranium 233 fuel. The three fuels can be controlled with soluble boron. The power distribution inside an assembly agrees with the safety rules and the worth of the control rods is sufficient. To be interesting the thorium fuels must be recycled. Because the activity and the residual power are higher for a thorium fuel than for a uranium fuel the shielding of the shipping casks and storage pools must be increased. The Uranium 235-Thorium fuel is the best even if it needs expensive enrichment work. With this type of fuel more natural uranium is saved. The thorium fuel would become very interesting if we observe again in the future an increase of the uranium cost

  6. Impact of Thorium Capture Cross Section Uncertainty on the Thorium Utilized ADS Reactivity Calculation

    Directory of Open Access Journals (Sweden)

    Thanh Mai Vu

    2014-01-01

    Full Text Available Recently, the researches on fast neutron spectrum system utilized thorium fuel are widely conducted. However, the recent thorium cross section libraries are limited compared to uranium cross section libraries. The impact of thorium cross section uncertainty on thorium fuel utilized accelerator driven system (ADS reactivity calculation is estimated in this study. The uncertainty of the keff caused by 232Th capture cross section of JENDL-4.0 is about 1.3%. The uncertainty of JENDL-4.0 is needed to be enhanced to provide more reliable results on reactivity calculation for the fast system. The impact of uncertainty of  232Th capture cross section of ENDF/B-VII is small (0.1%. Therefore, it will cause no significant impact of the thorium cross section library on the thorium utilized ADS design calculation.

  7. Method of separating thorium from plutonium

    Science.gov (United States)

    Clifton, D.G.; Blum, T.W.

    A method of chemically separating plutonium from thorium is claimed. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  8. Nuclear power from thorium - different approaches

    International Nuclear Information System (INIS)

    The importance of thorium for sustainability of nuclear power has been recognized way back in 1950's. High abundance in nature, a higher neutron yield per fission over a wide range of neutron energy (in the thermal and epithermal range), single valency of thorium which leads to higher stabilities of it's compounds and much reduced production of long lived radioactive waste in the Th-233U fuel cycle have made thorium a very attractive source material for generation of nuclear energy. The thorium based fuel cycle is associated with the generation of 232U. Some of the daughter products of 232U have short half-lives and emit strong gamma rays. Therefore, 233U related activities such as fuel fabrication and subsequent fuel handling would need shielding and remote access. The first part of the paper will summarize the basic advantages and associated problems with the operation of thorium fuel cycle. Thorium being a fertile material, it's utilization in the power generation program requires judicious adoption of appropriate fuel cycles. Different approaches for thorium utilization in solid fuelled, molten salt and accelerator driven subcritical reactor and their merits and demerits will be discussed. The scientific issues connected with thorium in heavy water and light water reactors have been examined in terms of in-situ burning of 233U, saving in uranium, Pu generation, enhancement of burn up, and reprocessing challenges. Based on the analyses it has been argued that for a country such as India where the fissile inventory is not large and the policy of closed fuel cycle is adopted, an early introduction of thorium can only reduce uranium consumption to a limited extent. However, for gaining experience in thorium fuel cycle and for evaluating performance of thorium based fuel experimental irradiation of such fuels of different compositions are in progress. Molten salt reactors are quite promising for Th-233U fuel cycles both from safety and fissile

  9. Thorium utilization in Candu reactors

    International Nuclear Information System (INIS)

    In this study, means of thorium utilization in a CANDU reactor are considered. A once through thorium-DUPIC cycle is analyzed in detail. CANDU has the best neutron economy among the commercially available power reactors, which makes it suitable for many different fuel cycle options. A review of the available fuel cycles is also done in the scope of this study to select an economically viable cycle which does not impose profound changes in the neutronic properties of the core that require remodeling of core and related systems. To create a good model ot the CANDU core for the necessary calculations, the steady state properties of CANDU reactor are analyzed. It is assumed that approximation ot refueling as moving the bundles at a constant velocity is valid. This approximation leads to a corollary; The average cross sections of two adjacent bidirectionally refueled channels are independent of axial location. This is also veritied. A result of this corollary the CANDU core can be modeled only in radial direction in cylindirical geometry. The steady state CANDU core model is prepared using the actual power values and these values are sought in the results. The control systems which effect the neutron flux shape are introduced into the model later in the form of additional absorption cross section and lower diffusion coefficient. The results are in good agreement with the actual values. Several different thorium-DUPIC fuel bundle configurations are considered and the one with 12 Th02 elements in the third ring is found to have similar burnup dependent cross-sections and location infinite multiplication factors. Using the model created, the bundle is tested also in the tull core model and it is tound that this bundle configuration complies with the current refueling scheme. That is, no changes are necessary in the refuelind rate or the control systems. A higher conversion ratio of 0.82 is attained, while the excess reactivity of the core is found to decrease by 0.01 Ak

  10. Thorium based fuel for AHWR

    International Nuclear Information System (INIS)

    Advanced Heavy Water Reactor (AHWR) is a 300 MWe, thoria fuel based, vertical pressure tube type reactor designed at BARC. It is heavy water moderated and boiling light water cooled reactor that has been designed for hundred years of plant life. The reactor design has evolved from the presently operating PHWRs and BWRs in India. AHWR has extensive deployment of passive safety features for its operation and accident mitigation at par with the present international standards and provides a robust design against external as well as internal threats. The physics design ensures inherent safety characteristics of the reactor. Heat removal from the core under both normal full power operating condition as well as shutdown condition is by natural circulation of water coolant. The physical characteristics of Thoria based fuel offer potential for high performance in reactor and slower fuel deterioration. With inherent feature of fuel cycle flexibility, a variety of fuel-types could be used in AHWR for generating power efficiently. AHWR-Pu version makes use of (Th-Pu) MOX and (Th-233U) MOX fuel in the closed fuel cycle mode. The adoption of the closed thorium fuel cycle on an industrial scale is for the first time and is important in view of very little global experience. The experience generated on the various fuel cycle activities will be useful in utilisation of the large thoria reserves as envisaged in India's three-stage nuclear power programme. This paper provides an overview of the various design aspects of the thorium based fuel for AHWR and its associated developmental activities. (author)

  11. The environmental behaviour of uranium and thorium

    International Nuclear Information System (INIS)

    Uranium and thorium have had many uses in the past, and their present and potential use as nuclear fuels in energy production is very significant. Both elements, and their daughter products, are of environmental interest because they may have effects from the time of mining to the time of ultimate disposal of used nuclear fuel. To assess the impact on the environment of man's use and disposal of uranium and thorium, we must know the physical, chemical and biological behaviour of these elements. This report summarizes the literature, updating and extending earlier reviews pertaining to uranium and thorium. The radiological properties, chemistry, forms of occurrence in nature, soil interactions, as well as distribution coefficients and mode of transport are discussed for both elements. In addition, uranium and thorium concentrations in plants, plant transfer coefficients, concentrations in soil organisms and methods of detection are summarized. (auth)

  12. Nuclear physics: Elusive transition spotted in thorium

    Science.gov (United States)

    Safronova, Marianna

    2016-05-01

    The highly precise atomic clocks used in science and technology are based on electronic transitions in atoms. The discovery of a nuclear transition in thorium-229 raises hopes of making nuclear clocks a reality. See Article p.47

  13. Thorium exposure in a niobium mine

    International Nuclear Information System (INIS)

    The workers involved in the mineral process to obtain Nb-Fe alloy are exposure to thorium. Internal contamination with radioactive materials is a common problem. This is caused by presence of U and Th and their natural decay series associated with the mine ore. The examples are the workers at the niobium mine located in the state of Goias. Twenty mine workers were evaluated using in vitro bioassay techniques. Samples of urine and feces from occupationally exposed mine workers were analyzed for thorium isotopes. The fecal samples corresponding to one complete excretion and urine sample corresponding to a 24 hours collection were analyzed using alpha spectrometry. The results of thorium excretion (feces) have shown that in all the samples the 228 Th excretions in high than 232 Th. Thorium concentration in all the urine samples were below limit of detection that is approximately 1 mBq/l. (author). 3 refs., 1 fig., 1 tab

  14. Measurement of lymphoblastogenic activity from thorium workers

    International Nuclear Information System (INIS)

    Mitogenic stimulation of peripheral blood lymphocyte cultures obtained from 36 thorium workers was studied to determine whether the response of these cells was affected by the individuals' occupational exposure to alpha irradiation. The standard assay involved incubating 2 x 105 lymphocytes per test well 72 hours in the presence of phytohemagglutinin (PHA), concanavalin A (Con A) or pokeweed mitogen (PWM). The results showed that there was a significant decrease in lymphocyte responsiveness of former thorium workers grouped by decade of life when compared with controls of the same decade of life for each mitogen tested with the exceptions of PHA in the 41-50 age group and PWM in the 51-60 age group. We are unable to correlate the decreased response observed with the measured body burdens, external gamma exposure, or thoron exhalation rates in these thorium cases. However, other occupational exposures (i.e., various chemicals used in processing thorium) cannot be eliminated as a possible cause. (author)

  15. Self-Sustaining Thorium Boiling Water Reactors

    OpenAIRE

    Ehud Greenspan; Jasmina Vujic; Francesco Ganda; Arias, Francisco J.

    2012-01-01

    A thorium-fueled water-cooled reactor core design approach that features a radially uniform composition of fuel rods in stationary fuel assembly and is fuel-self-sustaining is described. This core design concept is similar to the Reduced moderation Boiling Water Reactor (RBWR) proposed by Hitachi to fit within an ABWR pressure vessel, with the following exceptions: use of thorium instead of depleted uranium for the fertile fuel; elimination of the internal blanket; and elimination of absorber...

  16. Thorium residuals in West Chicago, Illinois

    International Nuclear Information System (INIS)

    Lindsay and Company began operation of its west Chicago, Illinois, plant in 1931, processing thorium ores for thorium and rare earths. From that time until normal operations ceased in 1973, thorium residuals from the operation found their way offsite to Reed-Keppler City Park, the West Chicago Sewage Treatment Plant, and numerous other locations about the city and its environs. The present study located and identified such thorium residuals in the West Chicago area, a total of 75 epicenters having been found in addition to deposits at Reed-Keppler Park, the sewage-treatment plant, and down Kress Creek and the DuPage River. Deposits proved to be almost exclusively the dense, gray, insoluble particles of thorium-ore tailings from the process, which have been historically stored in two large piles in the site waste area. Epicenter locations and associated radiological parameters are given for the 75 locations, along with quantitative descriptions of the larger collections of material at the park, at the sewage-treatment plant, and on the banks of Kress Creek and the DuPage River. Not one of the areas of thorium residuals located outside security fences was found to violate the requirements of 10 CFR 20

  17. Technology assessment of near-term open-cycle thorium-fuelled nuclear energy systems

    International Nuclear Information System (INIS)

    As part of the RCUK-India civil nuclear research collaboration, British and Indian researchers have sought to determine the advantages, disadvantages, and viability of open-cycle thorium-uranium fuelled (Th-U-fuelled) nuclear energy systems. The research centred on fuel cycle modelling and life-cycle assessment of three Th-U-fuelled nuclear energy systems and compared these to a reference uranium-fuelled nuclear energy system, all operating with open nuclear fuel cycles. The results indicate that thorium-based fuels offers little benefit over conventional uranium fuelled approaches for open-cycle nuclear energy production. This paper provides an overview on the project and stresses over-arching conclusions. (author)

  18. Recovery of uranium and thorium from uranium-thorium mixture by extraction-stripping

    International Nuclear Information System (INIS)

    An experiment has been conducted for the recovery of uranium and thorium from uranium-thorium mixture by extraction-stripping method. Thorium is one of the fission products of irradiated uranium fuel. This experiment aims to recover both uranium and thorium to be fed back as fuel. The samples for the extraction-stripping of uranium-thorium was made by varying mixtures of uranium-thorium for simulation, i.e. 5% U, 10% U, 15% U, 20% U, and 25% U, with a variation of extractant TBP of 25%, 30%, 35%, 40%, 48%, 60%, and 70%, while the amount/percentage of kerosene used as a diluent was in adjustment with the TBP percentage used. The stripping of the extracted product was done by using hot water at a temperature of 70°C with variation of nitric acid. The experimental results shows that uranium content of 93.6924% was obtained by TBP/kerosene composition of 30%/70% and 92.0754% thorium was obtained for TBP/kerosene composition of 48%/52%. The stripping results show that 98.6392% of thorium was obtained for stripping using hot water at 60-70°C with 0.6 N acidity, while 88.9873% of uranium was recovered for acidity of 0.5 N. (author)

  19. Thorium research activities in Japan

    International Nuclear Information System (INIS)

    The nuclear energy policy in Japan is based on the Uranium-Plutonium fuel cycle with Light Water Reactors (LWR) and Fast Breeder Reactors (FBR). After the accident at Fukushima-Daiichi Nuclear Power Plant, the Japanese government recognizes the importance to ensure the flexibility for future nuclear power generation and then, it was specified in the latest Japanese strategic energy plan. Two research groups related to thorium fuelled nuclear systems and fuel cycle was set up in the Atomic Energy Society of Japan in 2013. One is a 'Research Committee on Nuclear Applications of Molten Salt'. The committee was established to discuss the current molten-salt technology including molten-salt cooled reactor, molten-salt fuelled reactor, accelerator driven system, fusion reactor blankets and dry reprocessing processes. Throughout two years discussion, the committee summarizes a current state of the art and issues of molten-salt application systems. Committee also discussed the handling technologies for molten-salt reactors especially in China and United Kingdom, issues of molten-salt application to fusion reactor, dry reprocessing of spent nuclear fuel, and non-nuclear application of molten-salt. Term of the committee will be extended for further research activities

  20. Competitive biosorption of thorium and uranium by actinomycetes

    International Nuclear Information System (INIS)

    The competitive biosorption of thorium and uranium by actinomycetes was examined. Of the actinomycetes tested, Streptomyces levoris showed the highest ability to sorb both thorium and uranium from aqueous systems. Thorium sorption was not affected by co-existed uranium, while uranium sorption was strongly hindered by co-existed thorium. The amounts of both thorium and uranium sorbed by Streptomyces levoris cells increased with an increase of the solution pH. Although the equilibrium isotherm of uranium biosorption is in similar manner as that of thorium biosorption, uranium was sorbed much faster than thorium. Biosorption isotherm of each metal ion could be well fitted by Langmuir isotherm taking the ionic charge of metal ions into account. The Langmuir isotherm for binary system did not explain completely the competitive biosorption of thorium and uranium by Streptomyces levoris. However, the results suggested that the ion species of both metals in the cells should be Th(OH)22+ and UO22+, respectively. (author)

  1. Vil løyse global energikrise med thorium

    CERN Multimedia

    Aure, Gyri

    2007-01-01

    A professor from Bergen claims thorium can contribute to save the world from a global energy crisis. He wants Norway to construct the first accelerator driven reactor in the world powered by thorium. (5 pages)

  2. Composition of hydroponic medium affects thorium uptake by tobacco plants.

    Science.gov (United States)

    Soudek, Petr; Kufner, Daniel; Petrová, Sárka; Mihaljevič, Martin; Vaněk, Tomáš

    2013-08-01

    The ability of thorium uptake as well as responses to heavy metal stress were tested in tobacco cultivar La Burley 21. Thorium was accumulated preferentially in the root system. The presence of citric, tartaric and oxalic acids in hydroponic medium increased thorium accumulation in all plant organs. On the other hand, the addition of diamines and polyamines, the important antioxidants in plants, resulted in decrease of thorium accumulation, especially in the root system. Negative correlation was found between putrescine concentration and thorium accumulation. Nevertheless, the most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium that caused more than 10-fold increase of thorium uptake in all plant parts. Accumulation and distribution of thorium was followed in six cultivars and 14 selected transformants. Cultivar La Barley 21 represented an average between the tested genotypes, having a very good distribution ratio between roots, stems and leaves.

  3. Moving towards sustainable thorium fuel cycles

    International Nuclear Information System (INIS)

    The CANDU reactor has an unsurpassed degree of fuel-cycle flexibility as a consequence of its fuel-channel design, excellent neutron economy, on-power refueling, and simple fuel bundle design. These features facilitate the introduction and full exploitation of thorium fuel cycles in CANDU reactors in an evolutionary fashion. Thoria (ThO2) based fuel offers both fuel performance and safety advantages over urania (UO2) based fuel, due its higher thermal conductivity which results in lower fuel-operating temperatures at similar linear element powers. Thoria fuel has demonstrated lower fission gas release than UO2 under similar operating powers during test irradiations. In addition, thoria has a higher melting point than urania and is far less reactive in hypothetical accident scenarios owing to the fact that it has only one oxidation state. This paper examines one possible strategy for the introduction of thorium fuel cycles into CANDU reactors. In the short term, the initial fissile material would be provided in a heterogeneous bundle of low-enriched uranium and thorium. The medium term scenario uses homogeneous Pu/Th bundles in the CANDU reactor, further increasing the energy derived from the thorium. In the long term, the full energy potential from thorium would be realized through the recycle of the U-233 in the used fuel. With U-233 recycle in CANDU reactors, plutonium would then only be required to top up the fissile content to achieve the desired burnup. (author)

  4. Raman Spectroscopy for Analysis of Thorium Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yin-Fong; Johnson, Timothy J.; Olsen, Khris B.

    2016-05-12

    The thorium fuel cycle is an alternative to the uranium fuel cycle in that when 232Th is irradiated with neutrons it is converted to 233U, another fissile isotope. There are several chemical forms of thorium which are used in the Th fuel cycle. Recently, Raman spectroscopy has become a very portable and facile analytical technique useful for many applications, including e.g. determining the chemical composition of different materials such as for thorium compounds. The technique continues to improve with the development of ever-more sensitive instrumentation and better software. Using a laboratory Fourier-transform (FT)-Raman spectrometer with a 785 nm wavelength laser, we were able to obtain Raman spectra from a series of thorium-bearing compounds of unknown origin. These spectra were compared to the spectra of in-stock-laboratory thorium compounds including ThO2, ThF4, Th(CO3)2 and Th(C2O4)2. The unknown spectra showed very good agreement to the known standards, demonstrating the applicability of Raman spectroscopy for detection and identification of these nuclear materials.

  5. Raman spectroscopy for analysis of thorium compounds

    Science.gov (United States)

    Su, Yin-Fong; Johnson, Timothy J.; Olsen, Khris B.

    2016-05-01

    The thorium fuel cycle is an alternative to the uranium fuel cycle in that when 232Th is irradiated with neutrons it is converted to 233U, another fissile isotope. There are several chemical forms of thorium which are used in the Th fuel cycle. Recently, Raman spectroscopy has become a very portable and facile analytical technique useful for many applications, including e.g. determining the chemical composition of different materials such as for thorium compounds. The technique continues to improve with the development of ever-more sensitive instrumentation and better software. Using a laboratory Fourier-transform (FT)-Raman spectrometer with a 785 nm wavelength laser, we were able to obtain Raman spectra from a series of thorium-bearing compounds of unknown origin. These spectra were compared to the spectra of in-stock-laboratory thorium compounds including e.g. ThO2, ThF4, Th(CO3)2 and Th(C2O4)2. The unknown spectra showed very good agreement to the known standards, demonstrating the applicability of Raman spectroscopy for detection and identification of these nuclear materials.

  6. Determination of boron spectrophotometry in thorium sulfate

    International Nuclear Information System (INIS)

    A procedure for the determination of microquantities of boron in nuclear grade thorium sulfate is described. The method is based on the extraction of BF-4 ion associated to monomethylthionine (MMT) in 1,2 - dichloroethane. The extraction of the colored BF-4-MMT complex does not allow the presence of sulfuric and phosphoric acids; other anions interfere seriously. This fact makes the dissolution of the thorium sulfate impracticable, since it is insoluble in both acids. On the other hand, the quantitative separation of thorium is mandatory, to avoid the precipitation of ThF4. To overcome this difficulty, the thorium sulfate is dissolved using a strong cationic ion exchanger, Th4+ being totally retained into the resin. Boron is then analysed in the effluent. The procedure allows the determination of 0.2 to 10.0 microgramas of B, with a maximum error of 10%. Thorium sulfate samples with contents of 0.2 to 2.0μg B/gTh have being analysed

  7. Thorium: Does Crustal Abundance Lead to Economic Availability?

    OpenAIRE

    Brett W. Jordan; Rod Eggert; Brent Dixon; Brett Carlsen

    2014-01-01

    Recently, interest in thorium's potential use in a nuclear fuel cycle has been renewed. Thorium is more abundant, at least on average, than uranium in the earth's crust and, therefore, could theoretically extend the use of nuclear energy technology beyond the economic limits of uranium resources. This paper provides an economic assessment of thorium availability by creating cumulative-availability and potential mining-industry cost curves, based on known thorium resources. These tools provide...

  8. Composition of hydroponic medium affects thorium uptake by tobacco plants

    OpenAIRE

    Soudek, P. (Petr); Kufner, D. (Daniel); Petrová, Š. (Šárka); Mihaljevič, M.; Vaněk, T. (Tomáš)

    2013-01-01

    The ability of thorium uptake as well as responses to heavy metal stress were tested in tobacco cultivar La Burley 21. Thorium was accumulated preferentially in the root system. The presence of citric, tartaric and oxalic acids in hydroponic medium increased thorium accumulation in all plant organs. On the other hand, the addition of diamines and polyamines, the important antioxidants in plants, resulted in decrease of thorium accumulation, especially in the root system. Negative correlation ...

  9. Research of the thorium purification at monazite refinement processes

    Science.gov (United States)

    Shagalov, V. V.; Sobolev, V. I.; Turinskaya, M. V.; Malin, A. V.

    2016-06-01

    This paper is aimed to the research of the thorium purification processes at monazite refinement processes. We have investigated different solution containing thorium with different mix of rare-earth elements. It was found that the application of cation resin is well- recommended if we want to reach the highest yields of thorium purification process.

  10. Thorium removal by different adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Metaxas, Michail; Kasselouri-Rigopoulou, Vasilia; Galiatsatou, Polymnia; Konstantopoulou, Cathrine; Oikonomou, Dimitrios

    2003-02-28

    The removal of radiotoxic Th{sup 4+} from aqueous solutions has been explored using two different groups of adsorptive materials (e.g. two activated carbons and four zeolites--two natural and two synthetic). The activated carbons were prepared from solvent extracted olive pulp (SEOP) and olive stone (OS) by a two-step physical activation method with steam. They were characterized by N{sub 2} at 77 K adsorption, Hg porosimetry and by determination of their iodine number. All carbons prepared are of the H-type (e.g. contain mainly basic surface oxides) confirmed by the results of the Boehm's method. The natural zeolites, clinoptilolite (NaCLI) and mordenite (NaMOR), were pretreated with Na{sup +} before the adsorption experiments, while the synthetic ones, NaX and NaA, were provided in their commercial sodium form. The natural zeolites, NaCLI and NaMOR, utilized 11.5 and 38.6% of the theoretical ion-exchange capacity, based on Al content, respectively, while NaX and NaA utilized 41.5 and 45.9%, respectively. The activated carbons showed better removal capability than NaCLI. NaMOR, showed comparable results to the carbon originated from OS, but lower removal capability than the carbon originated from SEOP. The synthetic zeolites showed the highest removal ability for thorium ions due to their increased ion-exchange capacity because of their cleaner and larger framework channels and their higher number of ion-exchange sites. The carbons adsorption capacity mainly depends on the content and nature of functional surface groups. The adsorption data were fitted to Langmuir and Freundlich models. The former achieved best fits and was further applied to obtain the respective Langmuir constant and maximum adsorption capacity for each system.

  11. Reprocessing in the thorium fuel cycle

    International Nuclear Information System (INIS)

    An overview of the authors personal view is presented on open questions in regard to still required research and development work for the thorium fuel cycle before its application in a technical-industrial scale may be tackled. For a better understanding, all stations of the back-end of the thorium fuel cycle are briefly illustrated and their special features discussed. They include storage and transportation measures, all steps of reprocessing, as well as the entire radioactive waste treatment. Knowledge gaps are, as far as they are obvious, identified and proposals put forward for additional worthwile investigations. (orig.)

  12. Natural thorium resources and recovery: Options and impacts

    Science.gov (United States)

    Ault, Timothy; Van Gosen, Bradley S.; Krahn, Steven; Croff, Allen

    2016-01-01

    This paper reviews the front end of the thorium fuel cycle, including the extent and variety of thorium deposits, the potential sources of thorium production, and the physical and chemical technologies required to isolate and purify thorium. Thorium is frequently found within rare earth element–bearing minerals that exist in diverse types of mineral deposits, often in conjunction with other minerals mined for their commercial value. It may be possible to recover substantial quantities of thorium as a by-product from active titanium, uranium, tin, iron, and rare earth mines. Incremental physical and chemical processing is required to obtain a purified thorium product from thorium minerals, but documented experience with these processes is extensive, and incorporating thorium recovery should not be overly challenging. The anticipated environmental impacts of by-product thorium recovery are small relative to those of uranium recovery since existing mining infrastructure utilization avoids the opening and operation of new mines and thorium recovery removes radionuclides from the mining tailings.

  13. Developmental activities related to thorium purification and metal production

    International Nuclear Information System (INIS)

    A new process for selective recovery of thorium and uranium from thorium cake of monazite origin has been developed, where the thorium cake was dissolved in nitric acid and separation of U(VI) was carried out using tris-2 ethyl hexyl phosphate (TEHP) diluted with n-paraffin. The recovery of Th(IV) from raffinate solution containing large amount of rare earths was carried out using 1M TiAP/n-paraffin as solvent. Finally, thorium from organic phase was stripped using 0.05 M HNO3 and precipitated as thorium oxalate. Based on experimental results, a process flow-sheet has been proposed for selective recovery of uranium and thorium from monazite. For pure Th-metal, lab scale process has already been developed at UED and recently using this metal NFG has produced 99% pure thorium foils for Physical Research Laboratory, Ahmedabad as per their request

  14. The chemistry of thorium in the hydrosphere and the geosphere. Chemie des Thoriums in der Hydro- und in der Geosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.

    1990-01-29

    Taking as a basis the knowledge of the migration of radionuclides in the geosphere, the author investigates the chemistry of thorium (a radioactive element found in larger quantities in the natural environment) in natural aqueous solutions. The thorium is analysed in the low concentration range in pure water, in ground water, and in the ground water/sediment system. The impact of the hydrolysis, complex formation and colloid formation on the sorption of thorium is explained, and thorium tracer techniques are discussed (methods, performance, activity measurements). The author presents results of experiments with molar thorium solutions, of paper chromatography analyses, and of scintillation counting analyses. (HWJ).

  15. Practical introduction of thorium fuel cycles

    International Nuclear Information System (INIS)

    The pracitcal introduction of throrium fuel cycles implies that thorium fuel cycles compete economically with uranium fuel cycles in economic nuclear power plants. In this study the reactor types under consideration are light water reactors (LWRs), heavy water reactors (HWRs), high-temperature gas-cooled reactors (HTGRs), and fast breeder reactors (FBRs). On the basis that once-through fuel cycles will be used almost exclusively for the next 20 or 25 years, introduction of economic thorium fuel cycles appears best accomplished by commercial introduction of HTGRs. As the price of natural uranium increases, along with commercialization of fuel recycle, there will be increasing incentive to utilize thorium fuel cycles in heavy water reactors and light water reactors as well as in HTGRs. After FBRs and fuel recycle are commercialized, use of thorium fuel cycles in the blanket of FBRs appears advantageous when fast breeder reactors and thermal reactors operate in a symbiosis mode (i.e., where 233U bred in the blanket of a fast breeder reactor is utilized as fissile fuel in thermal converter reactors)

  16. Europe's Indians.

    Science.gov (United States)

    Feest, Christian F.

    1990-01-01

    American Indians are regularly cited as models by and for Europeans. On closer examination, these "Indians" turn out to be a fictional assemblage fabricated over the past five centuries to serve specific cultural and emotional needs of its inventors. Studies changing representations of the Indian as used by European cultures. (AF)

  17. Candu reactors with thorium fuel cycles

    International Nuclear Information System (INIS)

    Over the last decade and a half AECL has established a strong record of delivering CANDU 6 nuclear power plants on time and at budget. Inherently flexible features of the CANDU type reactors, such as on-power fuelling, high neutron economy, fuel channel based heat transport system, simple fuel bundle configuration, two independent shut down systems, a cool moderator and a defence-in-depth based safety philosophy provides an evolutionary path to further improvements in design. The immediate milestone on this path is the Advanced CANDU ReactorTM** (ACRTM**), in the form of the ACR-1000TM**. This effort is being followed by the Super Critical Water Reactor (SCWR) design that will allow water-cooled reactors to attain high efficiencies by increasing the coolant temperature above 5500C. Adaptability of the CANDU design to different fuel cycles is another technology advantage that offers an additional avenue for design evolution. Thorium is one of the potential fuels for future reactors due to relative abundance, neutronics advantage as a fertile material in thermal reactors and proliferation resistance. The Thorium fuel cycle is also of interest to China, India, and Turkey due to local abundance that can ensure sustainable energy independence over the long term. AECL has performed an assessment of both CANDU 6 and ACR-1000 designs to identify systems, components, safety features and operational processes that may need to be modified to replace the NU or SEU fuel cycles with one based on Thorium. The paper reviews some of these requirements and the associated practical design solutions. These modifications can either be incorporated into the design prior to construction or, for currently operational reactors, during a refurbishment outage. In parallel with reactor modifications, various Thorium fuel cycles, either based on mixed bundles (homogeneous) or mixed channels (heterogeneous) have been assessed for technical and economic viability. Potential applications of a

  18. Safety and Regulatory Issues of the Thorium Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ade, Brian [ORNL; Worrall, Andrew [ORNL; Powers, Jeffrey [ORNL; Bowman, Steve [ORNL; Flanagan, George [ORNL; Gehin, Jess [ORNL

    2014-02-01

    Thorium has been widely considered an alternative to uranium fuel because of its relatively large natural abundance and its ability to breed fissile fuel (233U) from natural thorium (232Th). Possible scenarios for using thorium in the nuclear fuel cycle include use in different nuclear reactor types (light water, high temperature gas cooled, fast spectrum sodium, molten salt, etc.), advanced accelerator-driven systems, or even fission-fusion hybrid systems. The most likely near-term application of thorium in the United States is in currently operating light water reactors (LWRs). This use is primarily based on concepts that mix thorium with uranium (UO2 + ThO2), add fertile thorium (ThO2) fuel pins to LWR fuel assemblies, or use mixed plutonium and thorium (PuO2 + ThO2) fuel assemblies. The addition of thorium to currently operating LWRs would result in a number of different phenomenological impacts on the nuclear fuel. Thorium and its irradiation products have nuclear characteristics that are different from those of uranium. In addition, ThO2, alone or mixed with UO2 fuel, leads to different chemical and physical properties of the fuel. These aspects are key to reactor safety-related issues. The primary objectives of this report are to summarize historical, current, and proposed uses of thorium in nuclear reactors; provide some important properties of thorium fuel; perform qualitative and quantitative evaluations of both in-reactor and out-of-reactor safety issues and requirements specific to a thorium-based fuel cycle for current LWR reactor designs; and identify key knowledge gaps and technical issues that need to be addressed for the licensing of thorium LWR fuel in the United States.

  19. Thorium and its future importance for nuclear energy generation

    Energy Technology Data Exchange (ETDEWEB)

    Lainetti, Paulo E.O., E-mail: lainetti@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Thorium was discovered in 1828 by the Swedish chemist Jons J. Berzelius. Despite some advantages over uranium for use in nuclear reactors, its main use, in the almost two centuries since its discovery, the use of thorium was restricted to use for gas mantles, especially in the early twentieth century. In the beginning of the Nuclear Era, many countries had interested on thorium, particularly during the 1950-1970 period. There are about 435 nuclear reactors in the world nowadays. They need more than 65.000 tons of uranium yearly. The future world energy needs will increase and, even if we assumed a conservative contribution of nuclear generation, it will be occur a significant increasing in the uranium prices, taking into account that uranium, as used in the present thermal reactors, is a finite resource. Thorium is nearly three times more abundant than uranium in the Earth's crust. Despite thorium is not a fissile material, {sup 232}Th can be converted to {sup 233}U (fissile) more efficiently than {sup 238}U to {sup 239}Pu. Besides this, since it is possible to convert thorium waste into nonradioactive elements, thorium is an environment-friendly alternative energy source. Thorium fuel cycle is also inherently resistant to proliferation. Some papers evaluate the thorium resources in Brazil over 1.200.000 metric t. Then, the thorium alternative must be seriously considered in Brazil for strategic reasons. In this paper a brief history of thorium is presented, besides a review of the world thorium utilization and a discussion about advantages and restrictions of thorium use. (author)

  20. Thorium: An energy source for the world of tomorrow

    Science.gov (United States)

    Revol, J.-P.

    2015-08-01

    To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy and to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered by some major developing countries as a key element of their energy strategy. However, developed countries do not seem to move fast enough in that direction, while global cooperation is highly desirable in this domain. Thorium is not fissile. Various possible ways of using thorium will be reviewed. However, an elegant option is to drive an "Accelerator Driven System (ADS)" with a proton accelerator, as suggested by Nobel Prize laureate Carlo Rubbia .

  1. Feasibility to produce uranium-233 from thorium in PHWR

    International Nuclear Information System (INIS)

    Uranium-233 is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. It is used as fuel in nuclear reactor. 233U is produced by irradiating thorium in fast reactor or thermal reactor. In this paper feasibility to produce 233U by irradiation of fuel bundles of thorium mixed with plutonium or irradiation of thorium bundles along with slightly enriched Uranium bundles in 220 MWe and 540 MWe PHWRs has been studied. Study shows that production of 233U is possible by irradiating few fuel bundles of PuTh or Thorium bundles along with SEU bundles without affecting the power operation and the safety related parameters. (author)

  2. Thorium: An energy source for the world of tomorrow

    Directory of Open Access Journals (Sweden)

    Revol J.-P.

    2015-01-01

    Full Text Available To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy and to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered by some major developing countries as a key element of their energy strategy. However, developed countries do not seem to move fast enough in that direction, while global cooperation is highly desirable in this domain. Thorium is not fissile. Various possible ways of using thorium will be reviewed. However, an elegant option is to drive an “Accelerator Driven System (ADS” with a proton accelerator, as suggested by Nobel Prize laureate Carlo Rubbia .

  3. Thorium: An energy source for the world of tomorrow ?

    CERN Document Server

    CERN. Geneva

    2014-01-01

    To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. The ThEC13 conference organized by iThEC at CERN last October has shown that thorium is seriously considered by developing countries as a key element of their energy strategy. Developed countries are also starting to move in the same direction. How thorium could make nuclear energy (based on thorium) acceptable to society will be discussed. Thorium can be used both to produce energy and to destroy nuclear waste. As thorium is not fissile, one elegant option is to use an accelerator, in so-called “Accelerator Driven Systems (ADS)”, as suggested by Carlo Rubbia. CERN’s important contributions to R&D on thorium related issues will be mentioned as well as the main areas where CERN could contribute to this field in the future.

  4. Computer simulations for thorium doped tungsten crystals

    Energy Technology Data Exchange (ETDEWEB)

    Eberhard, Bernd

    2009-07-17

    Tungsten has the highest melting point among all metals in the periodic table of elements. Furthermore, its equilibrium vapor pressure is by far the lowest at the temperature given. Thoria, ThO{sub 2}, as a particle dopant, results in a high temperature creep resistant material. Moreover, thorium covered tungsten surfaces show a drastically reduced electronic work function. This results in a tremendous reduction of tip temperatures of cathodes in discharge lamps, and, therefore, in dramatically reduced tungsten vapor pressures. Thorium sublimates at temperatures below those of a typical operating cathode. For proper operation, a diffusional flow of thorium atoms towards the surface has to be maintained. This atomic flux responds very sensitively on the local microstructure, as grain boundaries as well as dislocation cores offer ''short circuit paths'' for thorium atoms. In this work, we address some open issues of thoriated tungsten. A molecular dynamics scheme (MD) is used to derive static as well as dynamic material properties which have their common origin in the atomistic behavior of tungsten and thorium atoms. The interatomic interactions between thorium and tungsten atoms are described within the embedded atom model (EAM). So far, in literature no W-Th interaction potentials on this basis are described. As there is no alloying system known between thorium and tungsten, we have determined material data for the fitting of these potentials using ab-initio methods. This is accomplished using the full potential augmented plane wave method (FLAPW), to get hypothetical, i.e. not occurring in nature, ''alloy'' data of W-Th. In order to circumvent the limitations of classical (NVE) MD schemes, we eventually couple our model systems to external heat baths or volume reservoirs (NVT, NPT). For the NPT ensemble, we implemented a generalization of the variable cell method in combination with the Langevin piston, which results in a

  5. Uranium and thorium deposits of Northern Ontario

    International Nuclear Information System (INIS)

    This, the second edition of the uranium-thorium deposit inventory, describes briefly the deposits of uranium and/or thorium in northern Ontario, which for the purposes of this circular is defined as that part of Ontario lying north and west of the Grenville Front. The most significant of the deposits described are fossil placers lying at or near the base of the Middle Precambrian Huronian Supergroup. These include the producing and past-producing mines of the Elliot Lake - Agnew Lake area. Also included are the pitchblende veins spatially associated with Late Precambrian (Keweenawan) diabase dikes of the Theano Point - Montreal River area. Miscellaneous Early Precambrian pegmatite, pitchblende-coffinite-sulphide occurrences near the Middle-Early Precambrian unconformity fringing the Lake Superior basin, and disseminations in diabase, granitic rocks, alkalic complexes and breccias scattered throughout northern Ontario make up the rest of the occurrences

  6. Accelerator breeder with uranium, thorium target

    International Nuclear Information System (INIS)

    An accelerator breeder, that uses a low-enriched fuel as the target material, can produce substantial amounts of fissile material and electric power. A study of H2O- and D2O-cooled, UO2, U, (depleted U), or thorium indicates that U-metal fuel produces a good fissile production rate and electrical power of about 60% higher than UO2 fuel. Thorium fuel has the same order of magnitude as UO2 fuel for fissile-fuel production, but the generating electric power is substantially lower than in a UO2 reactor. Enriched UO2 fuel increases the generating electric power but not the fissile-material production rate. The Na-cooled breeder target has many advantages over the H2O-cooled breeder target

  7. Thorium fuel cycle study for PWR applications

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae Yong; Kim, Myung Hyun [Kyung Hee Univ., Seoul (Korea, Republic of)

    1997-12-31

    A nuclear design feasibility of thorium fueled high converting PWR was investigated. Two kinds of fuel design option were tested for the comparison with conventional UO{sub 2} fuel. The first one was an application of MHTGR pyro-carbon coated particle fuels. The other design was an application of MOX fuels as a ThO{sub 2}-PuO{sub 2} ceramic pellet. In the case of carbon-coated particle fuels, there was no benefit in nuclear design aspect because enrichment of U-235 was required over 5 w/o in order to match with the K-infinite of Ulchin-3/4 fuels. However, the use of thorium based plutonium fuels in PWR gave favorable aspects in nuclear design such as flatter K-infinite curve, lower M. T. C. and lower F. T. C. than that of UO{sub 2} fuel. (author). 6 refs., 3 tabs., 6 figs.

  8. Computer simulations for thorium doped tungsten crystals

    International Nuclear Information System (INIS)

    Tungsten has the highest melting point among all metals in the periodic table of elements. Furthermore, its equilibrium vapor pressure is by far the lowest at the temperature given. Thoria, ThO2, as a particle dopant, results in a high temperature creep resistant material. Moreover, thorium covered tungsten surfaces show a drastically reduced electronic work function. This results in a tremendous reduction of tip temperatures of cathodes in discharge lamps, and, therefore, in dramatically reduced tungsten vapor pressures. Thorium sublimates at temperatures below those of a typical operating cathode. For proper operation, a diffusional flow of thorium atoms towards the surface has to be maintained. This atomic flux responds very sensitively on the local microstructure, as grain boundaries as well as dislocation cores offer ''short circuit paths'' for thorium atoms. In this work, we address some open issues of thoriated tungsten. A molecular dynamics scheme (MD) is used to derive static as well as dynamic material properties which have their common origin in the atomistic behavior of tungsten and thorium atoms. The interatomic interactions between thorium and tungsten atoms are described within the embedded atom model (EAM). So far, in literature no W-Th interaction potentials on this basis are described. As there is no alloying system known between thorium and tungsten, we have determined material data for the fitting of these potentials using ab-initio methods. This is accomplished using the full potential augmented plane wave method (FLAPW), to get hypothetical, i.e. not occurring in nature, ''alloy'' data of W-Th. In order to circumvent the limitations of classical (NVE) MD schemes, we eventually couple our model systems to external heat baths or volume reservoirs (NVT, NPT). For the NPT ensemble, we implemented a generalization of the variable cell method in combination with the Langevin piston, which results in a set of Langevin equations, i.e. stochastic

  9. Thorium dioxide: properties and nuclear applications

    International Nuclear Information System (INIS)

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core

  10. Thorium dioxide: properties and nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Belle, J.; Berman, R.M. (eds.)

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

  11. Long term radiological impact of thorium extraction

    International Nuclear Information System (INIS)

    Thorium extraction produces a certain amount of radioactive wastes. Potential long term radiological impact of these residues has been calculated using the recent ICRP-68 ingestion dose factors in connection with the computing code DECAY, developed at Orsay and described in this work. This code solves the well known Bateman's equations which govern the time dependence of a set of coupled radioactive nuclei. Monazites will be very likely the minerals to be exploited first, in case of an extensive use of thorium as nuclear fuel. Because monazites contain uranium as well, mining residues will contain not only the descendants of 232Th and a certain proportion of non-extracted thorium (taken here to be 5%), but also this uranium, if left in the wastes for economical reasons. If no uranium would be present at all in the mineral, the potential radiotoxicity would strongly decrease in approximately 60 years, at the pace of the 5.8 years period of 228Ra, which becomes the longest-lived radionuclide of the 4n radioactive family in the residues. Moreover, there is no risk due to radon exhalation, because of the very short period of 220Rn. These significant differences between uranium and thorium mining have to be considered in view of some estimated long term real radiological impacts due to uranium residues, which could reach a value of the order of 1 mSv/year, the dose limit recommended for the public by the recent ICRP-60. (authors). 15 refs., 4 figs., 3 tabs., 43 appendices

  12. Remarks on the cavitation of Thorium-228

    CERN Document Server

    Cardone, F; Petrucci, A

    2010-01-01

    In this short note we would like to provide some useful remarks on our previous work about the piezonuclear decay of Thorium and in general about the methods and protocols that we used in the experiments on piezonuclear reactions. The purpose of these remarks is to highlight the critical points of the experiments and equipment in order to design future experiments that may obtain positive evidences or that can be as more comparable to previous ones as possible.

  13. Nitrite complexes of uranium and thorium.

    Science.gov (United States)

    Dulong, Florian; Pouessel, Jacky; Thuéry, Pierre; Berthet, Jean-Claude; Ephritikhine, Michel; Cantat, Thibault

    2013-03-25

    The first examples of inorganic nitrite complexes of the natural actinides are described, including the structures of the homoleptic thorium(IV) [PPh(4)](2)[Th(NO(2))(6)] and the uranyl(VI) [PPh(4)](2)[UO(2)(NO(2))(4)] complexes; the nitrite ligand can adopt two different coordination modes in the coordination sphere of the uranyl ion and is unstable towards reduction.

  14. A PWR Thorium Pin Cell Burnup Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Kevan Dean; Zhao, X.; Pilat, E. E; Hejzlar, P.

    2000-05-01

    As part of work to evaluate the potential benefits of using thorium in LWR fuel, a thorium fueled benchmark comparison was made in this study between state-of-the-art codes, MOCUP (MCNP4B + ORIGEN2), and CASMO-4 for burnup calculations. The MOCUP runs were done individually at MIT and INEEL, using the same model but with some differences in techniques and cross section libraries. Eigenvalue and isotope concentrations were compared on a PWR pin cell model up to high burnup. The eigenvalue comparison as a function of burnup is good: the maximum difference is within 2% and the average absolute difference less than 1%. The isotope concentration comparisons are better than a set of MOX fuel benchmarks and comparable to a set of uranium fuel benchmarks reported in the literature. The actinide and fission product data sources used in the MOCUP burnup calculations for a typical thorium fuel are documented. Reasons for code vs code differences are analyzed and discussed.

  15. Self-Sustaining Thorium Boiling Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Greenspan, Ehud [Univ. of California, Berkeley, CA (United States); Gorman, Phillip M. [Univ. of California, Berkeley, CA (United States); Bogetic, Sandra [Univ. of California, Berkeley, CA (United States); Seifried, Jeffrey E. [Univ. of California, Berkeley, CA (United States); Zhang, Guanheng [Univ. of California, Berkeley, CA (United States); Varela, Christopher R. [Univ. of California, Berkeley, CA (United States); Fratoni, Massimiliano [Univ. of California, Berkeley, CA (United States); Vijic, Jasmina J. [Univ. of California, Berkeley, CA (United States); Downar, Thomas [Univ. of Michigan, Ann Arbor, MI (United States); Hall, Andrew [Univ. of Michigan, Ann Arbor, MI (United States); Ward, Andrew [Univ. of Michigan, Ann Arbor, MI (United States); Jarrett, Michael [Univ. of Michigan, Ann Arbor, MI (United States); Wysocki, Aaron [Univ. of Michigan, Ann Arbor, MI (United States); Xu, Yunlin [Univ. of Michigan, Ann Arbor, MI (United States); Kazimi, Mujid [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Shirvan, Koroush [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Mieloszyk, Alexander [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Todosow, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, Nicolas [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, Lap [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-03-15

    The primary objectives of this project are to: Perform a pre-conceptual design of a core for an alternative to the Hitachi proposed fuel-self- sustaining RBWR-AC, to be referred to as a RBWR-Th. The use of thorium fuel is expected to assure negative void coefficient of reactivity (versus positive of the RBWR-AC) and improve reactor safety; Perform a pre-conceptual design of an alternative core to the Hitachi proposed LWR TRU transmuting RBWR-TB2, to be referred to as the RBWR-TR. In addition to improved safety, use of thorium for the fertile fuel is expected to improve the TRU transmutation effectiveness; Compare the RBWR-Th and RBWR-TR performance against that of the Hitachi RBWR core designs and sodium cooled fast reactor counterparts - the ARR and ABR; and, Perform a viability assessment of the thorium-based RBWR design concepts to be identified along with their associated fuel cycle, a technology gap analysis, and a technology development roadmap. A description of the work performed and of the results obtained is provided in this Overview Report and, in more detail, in the Attachments. The major findings of the study are summarized.

  16. Thorium: in search of a global solution

    CERN Multimedia

    Antonella Del Rosso

    2013-01-01

    Last week, an international conference held at CERN brought together the world’s main experts in the field of alternative nuclear technology for the first time to discuss the use of thorium for the production of energy and the destruction of nuclear waste. Among the different technologies presented and discussed at the conference was ADS (Accelerator-Driven Systems) which relies primarily on particle accelerators.   The conference Chair (far left), the organisers and some of the distinguished participants of the ThEC13 conference held at CERN from 27 to 31 October 2013. “CERN has always been interested in finding ways in which fundamental research can help to resolve the problems of society,” says Jean-Pierre Revol, a physicist at the ALICE experiment who recently retired from CERN and is President of iThEC, the international not-for-profit organisation which promotes research and development in the field of thorium and which organised the Thorium Energy 2013 (Th...

  17. Thorium in the workplace measurement intercomparison

    International Nuclear Information System (INIS)

    The monitoring of radionuclides in the nuclear industry has been recognized as the most straightforward way of assessing health and safety issues associated with the exposure of the workforce to potentially harmful radiation doses. Much of this is achieved by measurements in the workplace itself and by the bioassay and monitoring of workers in the industry. However, there also exists a significant 'non-nuclear' industry where workers are exposed to radioactive materials, for example where this involves thorium, which is made wide use of in the aerospace and other high technology industries. As such work involves the processing of thorium bearing materials, the workforce is potentially exposed to 232Th and its daughter nuclides. Thus, to monitor the workforce effectively, it is important to be able to measure both 232Th and the decay products of 232Th where they are in an unknown state of radioactive equilibrium and this is where monitoring laboratories may experience some difficulty. Accordingly, the Health and Safety Laboratory in the UK has organized a EC wide project on the monitoring of thorium in the 'non-nuclear' workplace; this project is currently ongoing. We report the results of the first intercomparison of this project involving two solutions of 232Th, one in radioactive equilibrium and one not in equilibrium with its daughters. The results are presented with some comments on how this intercomparison has progressed and how these first results will inform the rest of the project

  18. Self-Sustaining Thorium Boiling Water Reactors

    Directory of Open Access Journals (Sweden)

    Ehud Greenspan

    2012-10-01

    Full Text Available A thorium-fueled water-cooled reactor core design approach that features a radially uniform composition of fuel rods in stationary fuel assembly and is fuel-self-sustaining is described. This core design concept is similar to the Reduced moderation Boiling Water Reactor (RBWR proposed by Hitachi to fit within an ABWR pressure vessel, with the following exceptions: use of thorium instead of depleted uranium for the fertile fuel; elimination of the internal blanket; and elimination of absorbers from the axial reflectors, while increasing the length of the fissile zone. The preliminary analysis indicates that it is feasible to design such cores to be fuel-self-sustaining and to have a comfortably low peak linear heat generation rate when operating at the nominal ABWR power level of nearly 4000 MWth. However, the void reactivity feedback tends to be too negative, making it difficult to have sufficient shutdown reactivity margin at cold zero power condition. An addition of a small amount of plutonium from LWR used nuclear fuel was found effective in reducing the magnitude of the negative void reactivity effect and enables attaining adequate shutdown reactivity margin; it also flattens the axial power distribution. The resulting design concept offers an efficient incineration of the LWR generated plutonium in addition to effective utilization of thorium. Additional R&D is required in order to arrive at a reliable practical and safe design.

  19. Self-Sustaining Thorium Boiling Water Reactors

    International Nuclear Information System (INIS)

    The primary objectives of this project are to: Perform a pre-conceptual design of a core for an alternative to the Hitachi proposed fuel-self- sustaining RBWR-AC, to be referred to as a RBWR-Th. The use of thorium fuel is expected to assure negative void coefficient of reactivity (versus positive of the RBWR-AC) and improve reactor safety; Perform a pre-conceptual design of an alternative core to the Hitachi proposed LWR TRU transmuting RBWR-TB2, to be referred to as the RBWR-TR. In addition to improved safety, use of thorium for the fertile fuel is expected to improve the TRU transmutation effectiveness; Compare the RBWR-Th and RBWR-TR performance against that of the Hitachi RBWR core designs and sodium cooled fast reactor counterparts - the ARR and ABR; and, Perform a viability assessment of the thorium-based RBWR design concepts to be identified along with their associated fuel cycle, a technology gap analysis, and a technology development roadmap. A description of the work performed and of the results obtained is provided in this Overview Report and, in more detail, in the Attachments. The major findings of the study are summarized.

  20. Health status and body radioactivity of former thorium workers

    International Nuclear Information System (INIS)

    The objectives of the study are: (1) to assess possible health effects of employment in the thorium milling industry by comparison of mortality and morbidity characteristics of former thorium workers with those of suitable general populations; (2) to examine disease outcomes by estimated exposure levels of thorium and thoron daughter products for possible radiation-related effects; and (3) to determine the body distribution of inhaled thorium (and daughters) and rare earths in humans by radioactivity measurements in vivo and by analysis of autopsy samples. The principal end points for investigation are respiratory disease and cancers of lung, liver, bone, and bone marrow

  1. Thorium: An energy source for the world of tomorrow

    OpenAIRE

    Revol J.-P.

    2015-01-01

    To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy and to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered...

  2. Uranium and thorium in British arable crops and grass

    International Nuclear Information System (INIS)

    The uranium-238 and thorium-232 concentrations of 59 crop samples from ten locations in England have been determined using inductively coupled plasma-mass spectrometry. The samples were collected at harvesting time during the summer and autumn of 1988. The levels of uranium and thorium in the crops ranged from -1 for uranium and from -1 for thorium. A general increase in the uranium and the thorium concentration of the crops was observed as follows: root crop flesh 40K and about 20% due to 210Pb and 210Po. (author)

  3. Economics and utilization of thorium in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    1978-05-01

    Information on thorium utilization in power reactors is presented concerning the potential demand for nuclear power, the potential supply for nuclear power, economic performance of thorium under different recycle policies, ease of commercialization of the economically preferred cases, policy options to overcome institutional barriers, and policy options to overcome technological and regulatory barriers.

  4. Strategy for the practical utilization of thorium fuel cycles

    International Nuclear Information System (INIS)

    There has been increasing interest in the utilization of thorium fuel cycles in nuclear power reactors for the past few years. This is due to a number of factors, the chief being the recent emphasis given to increasing the proliferation resistance of reactor fuel cycles and the thorium cycle characteristic that bred 233U can be denatured with 238U (further, a high radioactivity is associated with recycle 233U, which increases fuel diversion resistance). Another important factor influencing interest in thorium fuel cycles is the increasing cost of U3O8 ores leading to more emphasis being placed on obtaining higher fuel conversion ratios in thermal reactor systems, and the fact that thorium fuel cycles have higher fuel conversion ratios in thermal reactors than do uranium fuel cycles. Finally, there is increasing information which indicates that fast breeder reactors have significantly higher capital costs than do thermal reactors, such that there is an economic advantage in the long term to have combinations of fast breeder reactors and high-conversion thermal reactors operating together. Overall, it appears that the practical, early utilization of thorium fuel cycles in power reactors requires commercialization of HTGRs operating first on stowaway fuel cycles, followed by thorium fuel recycle. In the longer term, thorium utilization involves use of thorium blankets in fast breeder reactors, in combination with recycling the bred 233U to HTGRs (preferably), or to other thermal reactors

  5. Content of Transuranium Nuclide in Process of Irradiating Thorium

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Currently, sufficient nuclear fuel supply is most important problem with the nuclear power grow rapidly, so the use of thorium fuel is being put on the agenda. The applicability of thorium as a power reactor is based on a (n, γ) reaction on 232Th. The consequent nucleus, 233Th,

  6. Principal thorium resources in the United States

    Science.gov (United States)

    Staatz, Mortimer Hay; Armbrustmacher, T.J.; Olson, J.C.; Brownfield, I.K.; Brock, M.R.; Lemons, J.F.; Coppa, L.V.; Clingan, B.V.

    1979-01-01

    Resources were assessed for thorium in the higher grade and better known deposits in the United States in: (1) veins, (2) massive carbonatites, (3) stream placers of North and South Carolina, and (4) disseminated deposits. Thorium resources for the first three categories were divided into reserves and probable potential resources. Each of these then were separated into the following cost categories: (1) the amount of ThO2 producible at less than $15 per pound, (2) the amount producible at between $15 and $30 per pound, and (3) the amount producible at more than $50 per pound. The type of mining and milling needed at each deposit determines the capital, operating, and fixed costs of both mining and milling. Costs start with the clearing of land and are carried through to the final product, which for all deposits is ThO2. Capital costs of mining are affected most by the type of mining and the size of the mine. Those of milling are affected most by the kind of mill, its size, and whether or not extra circuits are needed for the separation of rare earths or some other byproduct. Veins, massive carbonatites, and stream placers of North and South Carolina have reserves of 188,000 short tons of ThO2 and probable potential resources of 505,000 tons of ThO2. Approximately half of the reserves and probable potential resources can be produced at less than $30 per pound of ThO2. Veins are the highest grade source in the United States and have total reserves of 142,000 tons of ThO2 and probable potential resources of 343,000 tons. About 90 percent of the reserves and 91 percent of the probable potential resources can be produced at less than $15 per pound of ThO2. Seven vein districts were evaluated: (1) Lemhi Pass, Mont.-Idaho, (2) Wet Mountains, Colo., (3) Powderhorn, Colo., (4) Hall Mountain, Idaho, (5) Diamond Creek, Idaho, (6) Bear Lodge Mountains, Wyo. and (7) Mountain Pass, Calif. Eighty-seven percent of the total reserves and probable potential resources are in the

  7. Determination of Thorium and Ruthenium in Diuranate by ICP-AES

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Qian-ci; TAO; Miao-miao; LUO; Zhong-yan; ZHAO; Li-fei; HAO; Xiao-juan

    2012-01-01

    <正>Thorium and ruthenium are important impurities that should be monitored in diuranate product. A method for determination of thorium and ruthenium in diuranate was established. Due to the complicated atomic lines of uranium, which have strict interference with that of thorium and ruthenium during determination by ICP-AES, thorium and ruthenium should be separated firstly from uranium matrix before measurement.

  8. An evaluation of once-through homogeneous thorium fuel cycle for light water reactors

    International Nuclear Information System (INIS)

    The other ways enhancing the economic potential of thorium fuel has been assessed ; the utilization of lower enriched uranium in thorium-uranium fuel, duplex thorium fuel concept, thorium utilization in the mixed core with uranium fuel assembly and thorium blanket utilization in the uranium core. The fuel economics of the proposed ways of thorium fuel increased compared to the previous homogeneous thorium fuel cycle. Compared to uranium fuel cycle, however, they do not show any economic incentives. From the view of proliferation resistance potential, thorium fuel option has the advantage to reduce the inventory of plutonium production. Any of proposed thorium options are less economical than uranium fuel option, the thorium fuel option has the potential to be utilized in the future for the sake of the effective consumption of excessive plutonium and the preparation against the using up of uranium resource

  9. Evolution of uranium and thorium minerals

    Science.gov (United States)

    Hazen, R. M.; Ewing, R. C.; Sverjensky, D. A.

    2009-12-01

    The origins and near-surface distributions of the approximately 250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (UO2), thorianite (ThO2) and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several weight percent Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides. Earth’s third phase of uranium mineral evolution, during which most known U minerals first precipitated from reactions of soluble uranyl (U6+O2)2+ complexes, followed the Great Oxidation Event (GOE) at ~2.2 Ga and thus was mediated indirectly by biologic activity. Most uraninite deposited during this phase was low in Th and precipitated from saline and oxidizing hydrothermal solutions (100 to 300°C) transporting (UO2)2+-chloride complexes. Examples include the unconformity- and vein-type U deposits (Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport of (UO2)2+ complexes in the upper crust may reflect the availability of CaSO4-bearing evaporites after the GOE. During this phase, most uranyl minerals would have been able to form in the O2-bearing near-surface environment for the first time through weathering processes. The fourth phase of uranium mineralization began approximately 400 million years ago, as the rise of land plants

  10. Thorium-based nuclear fuel: current status and perspectives

    International Nuclear Information System (INIS)

    Until the present time considerable efforts have already been made in the area of fabrication, utilization and reprocessing of Th-based fuels for different types of reactors, namely: by FRG and USA - for HTRs; FRG and Brazil, Italy - for LWRs; India - for HWRs and FBRs. Basic research of thorium fuels and thorium fuel cycles are also being undertaken by Australia, Canada, China, France, FRG, Romania, USSR and other countries. Main emphasis has been given to the utilization of thorium fuels in once-through nuclear fuel cycles, but in some projects closed thorium-uranium or thorium-plutonium fuel cycles are also considered. The purpose of the Technical Committee on the Utilization of Thorium-Based Nuclear Fuel: Current Status and Perspective was to review the world thorium resources, incentives for further exploration, obtained experience in the utilization of Th-based fuels in different types of reactors, basic research, fabrication and reprocessing of Th-based fuels. As a result of the panel discussion the recommendations on future Agency activities and list of major worldwide activities in the area of Th-based fuel were developed. A separate abstract was prepared for each of the 9 papers in this proceedings series

  11. Environmental control technology for mining, milling, and refining thorium

    Energy Technology Data Exchange (ETDEWEB)

    Weakley, S.A.; Blahnik, D.E.; Young, J.K.; Bloomster, C.H.

    1980-02-01

    The purpose of this report is to evaluate, in terms of cost and effectiveness, the various environmental control technologies that would be used to control the radioactive wastes generated in the mining, milling, and refining of thorium from domestic resources. The technologies, in order to be considered for study, had to reduce the radioactivity in the waste streams to meet Atomic Energy Commission (10 CFR 20) standards for natural thorium's maximum permissible concentration (MPC) in air and water. Further regulatory standards or licensing requirements, either federal, state, or local, were not examined. The availability and cost of producing thorium from domestic resources is addressed in a companion volume. The objectives of this study were: (1) to identify the major waste streams generated during the mining, milling, and refining of reactor-grade thorium oxide from domestic resources; and (2) to determine the cost and levels of control of existing and advanced environmental control technologies for these waste streams. Six potential domestic deposits of thorium oxide, in addition to stockpiled thorium sludges, are discussed in this report. A summary of the location and characteristics of the potential domestic thorium resources and the mining, milling, and refining processes that will be needed to produce reactor-grade thorium oxide is presented in Section 2. The wastes from existing and potential domestic thorium oxide mines, mills, and refineries are identified in Section 3. Section 3 also presents the state-of-the-art technology and the costs associated with controlling the wastes from the mines, mills, and refineries. In Section 4, the available environmental control technologies for mines, mills, and refineries are assessed. Section 5 presents the cost and effectiveness estimates for the various environmental control technologies applicable to the mine, mill, and refinery for each domestic resource.

  12. Environmental control technology for mining, milling, and refining thorium

    International Nuclear Information System (INIS)

    The purpose of this report is to evaluate, in terms of cost and effectiveness, the various environmental control technologies that would be used to control the radioactive wastes generated in the mining, milling, and refining of thorium from domestic resources. The technologies, in order to be considered for study, had to reduce the radioactivity in the waste streams to meet Atomic Energy Commission (10 CFR 20) standards for natural thorium's maximum permissible concentration (MPC) in air and water. Further regulatory standards or licensing requirements, either federal, state, or local, were not examined. The availability and cost of producing thorium from domestic resources is addressed in a companion volume. The objectives of this study were: (1) to identify the major waste streams generated during the mining, milling, and refining of reactor-grade thorium oxide from domestic resources; and (2) to determine the cost and levels of control of existing and advanced environmental control technologies for these waste streams. Six potential domestic deposits of thorium oxide, in addition to stockpiled thorium sludges, are discussed in this report. A summary of the location and characteristics of the potential domestic thorium resources and the mining, milling, and refining processes that will be needed to produce reactor-grade thorium oxide is presented in Section 2. The wastes from existing and potential domestic thorium oxide mines, mills, and refineries are identified in Section 3. Section 3 also presents the state-of-the-art technology and the costs associated with controlling the wastes from the mines, mills, and refineries. In Section 4, the available environmental control technologies for mines, mills, and refineries are assessed. Section 5 presents the cost and effectiveness estimates for the various environmental control technologies applicable to the mine, mill, and refinery for each domestic resource

  13. Radiological impact assessment for near surface disposal of thorium waste

    International Nuclear Information System (INIS)

    Thorium (232Th) itself is not fissile and so is not directly usable in a thermal neutron reactor. However, it is fertile and upon absorbing a neutron will transmute to uranium-233 (233U), which is a fissile fuel material. The thorium fuel fabrication may lead to low level waste comprising of 232Th. This waste may be disposed of in the Near Surface Disposal Facility (NSDF). The very low probability event of leaching of the waste may lead to contamination of the groundwater system. This paper deals with the estimation of the radiological impact of thorium waste disposal in NSDF through groundwater drinking pathway using the Multiple Area Source Model (MASOM). (author)

  14. Immobilization of thorium over fibroin by polyacrylonitrile (PAN)

    Energy Technology Data Exchange (ETDEWEB)

    Aslani, M.A.A.; Akyil, S.; Eral, M. [Ege Univ. Inst. of Nuclear Sciences, Bornova-Izmir (Turkey)

    1997-12-31

    This report describes a process for immobilization of thorium over fibroin, which was used as a bio-adsorbant, by polyacrylonitrile. The amounts of thorium in aqueous solutions which may be leached in various aqueous ambients were detected by a spectrophotometer. The results show that polyacrylonitrile processes are feasible to immobilize spent fibroins. The leachability of the materials immobilized with polyacrylonitrile can meet the requirements of storage and final disposal. The leachability of thorium ions from immobilized spent fibroin was rather low for 8 months.

  15. Bioaccumulation of uranium and thorium from the solution containing both elements using various microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Tsuruta, T. [Department of Applied Chemistry, Tohwa University, 1-1-1 Chikushigaoka, Fukuoka 815-8510 (Japan)]. E-mail: ttsuruta@tohwa-u.ac.jp

    2006-02-09

    The effects of proton, thorium and uranium on the bioaccumulation of thorium and uranium from the solution (pH 3.5) containing uranium and thorium using Streptomyces levoris cells were examined. The amount of thorium accumulated using the cells decreased by the pre-contact between the cells and the solution (pH 3.5) containing no metals, whereas that of uranium was almost unaffected by the treatment. The amount of thorium was almost unaffected by the existence of uranium. On the other hand, the amount of uranium accumulated was strongly affected by the thorium, especially thorium addition after uranium accumulation. The decrease of uranium accumulated by the addition of thorium after the accumulation of uranium was higher than that from the solution containing both elements. Therefore, the contribution of uranium-thorium exchange reaction was higher than that of competition reaction. Accordingly, proton-uranium-thorium exchange reaction was occurred in the accumulation of thorium from the solution containing thorium and uranium. The gram-positive bacteria, such as Micrococcus luteus, Arthrobacter nicotianae, Bacillus subtilis and B. megaterium, has a much higher separation factor as thorium/uranium than that of actinomycetes. These gram-positive bacterial strains can be used for the accumulation of thorium from the solution containing uranium and thorium.

  16. Indian Summer

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, E. [Sho-Ban High School, Fort Hall, ID (United States)

    1997-08-01

    This paper focuses on preserving and strengthening two resources culturally and socially important to the Shoshone-Bannock Indian Tribe on the Fort Hall Reservation in Idaho; their young people and the Pacific-Northwest Salmon. After learning that salmon were not returning in significant numbers to ancestral fishing waters at headwater spawning sites, tribal youth wanted to know why. As a result, the Indian Summer project was conceived to give Shoshone-Bannock High School students the opportunity to develop hands-on, workable solutions to improve future Indian fishing and help make the river healthy again. The project goals were to increase the number of fry introduced into the streams, teach the Shoshone-Bannock students how to use scientific methodologies, and get students, parents, community members, and Indian and non-Indian mentors excited about learning. The students chose an egg incubation experiment to help increase self-sustaining, natural production of steelhead trout, and formulated and carried out a three step plan to increase the hatch-rate of steelhead trout in Idaho waters. With the help of local companies, governmental agencies, scientists, and mentors students have been able to meet their project goals, and at the same time, have learned how to use scientific methods to solve real life problems, how to return what they have used to the water and land, and how to have fun and enjoy life while learning.

  17. OPTIMIZATION OF HETEROGENEOUS UTILIZATION OF THORIUM IN PWRS TO ENHANCE PROLIFERATION RESISTANCE AND REDUCE WASTE.

    Energy Technology Data Exchange (ETDEWEB)

    TODOSOW,M.; KAZIMI,M.

    2004-08-01

    Issues affecting the implementation, public perception and acceptance of nuclear power include: proliferation, radioactive waste, safety, and economics. The thorium cycle directly addresses the proliferation and waste issues, but optimization studies of core design and fuel management are needed to ensure that it fits within acceptable safety and economic margins. Typical pressurized water reactors, although loaded with uranium fuel, produce 225 to 275 kg of plutonium per gigawatt-year of operation. Although the spent fuel is highly radioactive, it nevertheless offers a potential proliferation pathway because the plutonium is relatively easy to separate, amounts to many critical masses, and does not present any significant intrinsic barrier to weapon assembly. Uranium 233, on the other hand, produced by the irradiation of thorium, although it too can be used in weapons, may be ''denatured'' by the addition of natural, depleted or low enriched uranium. Furthermore, it appears that the chemical behavior of thoria or thoria-urania fuel makes it a more stable medium for the geological disposal of the spent fuel. It is therefore particularly well suited for a once-through fuel cycle. The use of thorium as a fertile material in nuclear fuel has been of interest since the dawn of nuclear power technology due to its abundance and to potential neutronic advantages. Early projects include homogeneous mixtures of thorium and uranium oxides in the BORAX-IV, Indian Point I, and Elk River reactors, as well as heterogeneous mixtures in the Shippingport seed-blanket reactor. However these projects were developed under considerably different circumstances than those which prevail at present. The earlier applications preceded the current proscription, for non-proliferation purposes, of the use of uranium enriched to more than 20 w/o in {sup 235}U, and has in practice generally prohibited the use of uranium highly enriched in {sup 235}U. They were designed when

  18. Development of a methodology for the determination of americium and thorium by ICP-AES and their inter-element effect

    International Nuclear Information System (INIS)

    Due to the scarcity of good quality uranium resources, the growth of nuclear technology in India is dependent on the utilization of the vast thorium resources. Therefore, Advance Heavy Water Reactor is going to acquire significant role in the scenario of Indian nuclear technology, where (Th, Pu)O2 will be utilized as fuel in the outermost ring of the reactor core. This will lead to a complex matrix containing thorium as well as americium, which is formed due to β-decay of plutonium. The amount of americium is dependent on the burn up and the storage time of the Pu based fuels. In the present case, attempt was made to develop a method for the determination of americium as well as thorium by ICP-AES. Two emission lines of americium were identified and calibration curves were established for determination of americium. Though the detection limit of 283.236 nm line (5 ng mL-1) of americium was found to be better than that of 408.930 nm (11 ng mL-1), the former line is significantly interfered by large amount of thorium. Three analytical lines (i.e. 283.242, 283.730 and 401.913 nm) of thorium were identified and calibration curves were established along with their detection limits. It was observed that 283.242 and 401.913 nm line are having similar detection limits (18 and 13 ng mL-1, respectively) which are better than that of 283.730 nm (60 ng mL-1). This can be attributed to the high background of 283.273 nm channel of thorium. The spectral interference study revealed that even small amount of americium has significant contribution on 283.242 nm channel of thorium while the other two channels remain practically unaffected. Considering both these facts, spectral interference and analytical performance (detection limits and sensitivity), it was concluded that 401.913 nm line is the best analytical line out of the three lines for determination of thorium in presence of americium. (author)

  19. Biosorption of uranium, thorium and radium

    International Nuclear Information System (INIS)

    The present study provides a historical background of uranium ore processing, radium extraction, and thorium production; a summary of the development of environmental regulations relative to uranium mill tailing (UMT) management; and an overview of the major factors influencing the biosorption of radionuclides. In addition, kinetic and mass transfer parameters of uranium uptake from synthetic solutions and UMT effluents by calcium alginate beads were determined. Kinetic values vm and K for uranium biosorption were calculated to be 10.3 mg/L/min and 63 g bead/L, respectively. A mathematical expression was derived to determine the associated biosorption diffusion coefficient which was calculated to be 9.20 x 10-8 cm2/s. The importance of these findings as they relate to the literature are discussed

  20. Determination of Micro-amount Thorium in Quadrivalent Cation System

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Thorium is one of the impurity elements that need to be controlled strictly in nuclear products. Therefore, it’s useful to establish a method characterized with high sensitivity and selectivity. The sample

  1. Tables for determining lead, uranium, and thorium isotope ages

    Science.gov (United States)

    Schonfeld, E.

    1974-01-01

    Tables for determining lead, uranium, and thorium isotope ages are presented in the form of computer printouts. Decay constants, analytical expressions for the functions evaluated, and the precision of the calculations are briefly discussed.

  2. Treatment of uranium and thorium bearing nitrate effluent

    International Nuclear Information System (INIS)

    Indigenously designed Advanced Heavy Water Reactor utilises (Th-LEU)O2 MOX as the fuel. During fabrication of MOX fuel, pellets not meeting the quality requirements will be recycled by wet processing for the recovery of uranium and thorium. The present study investigates the feasibility of various processes on the treatment of thorium bearing effluent arising from wet processing of reject MOX pellets. Process involving the reductive precipitation of uranium by sodium dithionite followed by adsorption of thorium onto inorganic sorbent, MST was developed and optimized. Reproducibility of the process under scale up conditions was also established. Under the optimized parameters, percentage removal obtained for uranium, thorium and radium was 99%, 97% and 98% respectively. (author)

  3. Uranium and thorium behavior at aluminium floating-zone refining

    International Nuclear Information System (INIS)

    Uranium and thorium behaviour during aluminium refining by crystallization from the melt is ascertained. Measurements of of uranium and thorium radioactive impurities content in high-purity aluminiumn samples using the surface α-activity method are carried out. The content of the given impurities happened to be less than 1 x 10-7 mass.%. Such purity satisfies the requirements to materials applied in the low background 71Ge detection system of gallium-germanium solar neutrino detector

  4. Method of synthesis of anhydrous thorium(IV) complexes

    Science.gov (United States)

    Kiplinger, Jaqueline L; Cantat, Thibault

    2013-04-30

    Method of producing anhydrous thorium(IV) tetrahalide complexes, utilizing Th(NO.sub.3).sub.4(H.sub.2O).sub.x, where x is at least 4, as a reagent; method of producing thorium-containing complexes utilizing ThCl.sub.4(DME).sub.2 as a precursor; method of producing purified ThCl.sub.4(ligand).sub.x compounds, where x is from 2 to 9; and novel compounds having the structures: ##STR00001##

  5. The use of thorium as an alternative nuclear fuel

    International Nuclear Information System (INIS)

    The use of thorium as an alternative or supplementary nuclear fuel is examined and compared with uranium. A description of various reactor types and their suitability to thorium fuel, and a description of various aspects of the fuel cycle from mining to waste disposal, are included. Comments are made on the safety and economics of each aspect of the fuel cycle and the extension of the lifetime of nuclear fuel

  6. Techno-economic assessment of thorium power in Canada

    International Nuclear Information System (INIS)

    Highlights: • Costs of replacing uranium in Canada’s nuclear reactors with thorium evaluated. • Results show a thorium plant to be more financially lucrative than a uranium plant. • Results were most sensitive to electricity price, then capital and decommissioning cost. • Abatement cost analysis showed nuclear power offers cost savings over fossil fuels. - Abstract: Thorium fission is a large yet relatively unexplored renewable energy source and could help feed increasing energy demands. An analysis was performed on the feasibility of replacing the uranium in Canada’s nuclear reactors with thorium. Thorium only exists as a fertile isotope, and so an external fissile source such as 235U, 233U, or 239Pu is required to stimulate the fission process. A uranium plant and a similar thorium-fuelled plant were compared over a 40 year operational life based on a comprehensive economic analysis. The results from the economic analysis were used to estimate the greenhouse gas (GHG) abatement cost compared to the coal and natural gas-based power. The economic analysis determined that a thorium plant is more financially lucrative in Canada than a uranium plant. An abatement cost assessment in relation to gas-fired and coal-fired power plants demonstrated that nuclear power offers a cost savings per tonne of CO2 equivalent greenhouse gas (GHG) when compared to both fossil fuel alternatives. From the values determined for a plant potentially fuelled on thorium, the abatement cost when compared to the coal-fired and gas-fired plants is −$10.4/tonne-CO2eq and −$15.7/tonne-CO2eq, respectively

  7. The indispensable role of thorium for creating a sustainable society

    International Nuclear Information System (INIS)

    Several approaches are required in parallel for constructing a sustainable society. One of them is to fight against global warming. The other one is to make this world nuclear weapon free. Nuclear power has been used for peaceful purpose because nuclear power produces electricity without emitting CO2. Nearly 15% of world electricity is produced by nuclear power. Through nuclear power plant has a possibility of severe accident such as Fukushima Daiichi, its advantage is still valuable for the world. President Obama's speech in Prague in 2009 brought a impact to the world to move toward the world without nuclear weapon. The remaining subject is how to treat dismantled fissionable materials. Existing nuclear power plants utilize uranium because only uranium contains natural occurring fissionable material, uranium-235. The spent uranium fuel contains fissionable plutonium-239. Thus, uranium fuel cycle always accompanies possibility of nuclear proliferation. Thorium plays an important role for both solving global warming and nuclear weapon. Fertile thorium can be used as nuclear fuel by support of fissionable plutonium-239 from spent uranium fuel or weapon head. Preliminary calculation indicates that the USA's and Russia's dismantle nuclear weapon enable to start more than 10 GWe of thorium nuclear power plants. In addition, plutonium-239 obtained from uranium fuel is available of 392 GWe of thorium nuclear power. Uranium-233 coming from thorium is also a fissionable but it is hard to be used for weapon because of its accompanied gamma-ray. Thorium itself is now obtained as by-product of rare-earth mining, which is used for high-tech products including photovoltaic cell, wind-mill, and hybrid-vehicle. However, thorium is not taken care adequately and becomes environmental hazard. Both to take care of environment, to support implementation of high-tech product and to make the world without nuclear weapon, a comprehensive role of thorium will be presented

  8. Material requirements for a thorium based nuclear fuel

    OpenAIRE

    Galiana Gonzalez, Bernat

    2010-01-01

    The increase in the energy consumption and the expected growth in the nuclear capacity make it necessary to look for alternative fuels to replace uranium. The fuel chosen, which was also considered in the early stages of nuclear energy, is thorium. Thorium has some characteristics that make it valuable as a fuel, like its abundance, the low radiotoxicity of the waste generated, the higher economy regarding its larger absorption cross-section and higher burnups and the prolifera...

  9. Estimating terrestrial uranium and thorium by antineutrino flux measurements

    OpenAIRE

    Dye, Stephen T.; Guillian, Eugene H.

    2008-01-01

    Uranium and thorium within the Earth produce a major portion of terrestrial heat along with a measurable flux of electron antineutrinos. These elements are key components in geophysical and geochemical models. Their quantity and distribution drive the dynamics, define the thermal history, and are a consequence of the differentiation of the Earth. Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations. This research report desc...

  10. Assessment of the thorium fuel cycle in power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Homan, F.J.; Allen, E.J.

    1977-01-01

    A study was conducted at Oak Ridge National Laboratory to evaluate the role of thorium fuel cycles in power reactors. Three thermal reactor systems were considered: Light Water Reactors (LWRs); High-Temperature Gas-Cooled Reactors (HTGRs); and Heavy Water Reactors (HWRs) of the Canadian Deuterium Uranium Reactor (CANDU) type; most of the effort was on these systems. A summary comparing thorium and uranium fuel cycles in Fast Breeder Reactors (FBRs) was also compiled.

  11. Separation of Protactinium from Neutron Irradiated Thorium Oxide

    International Nuclear Information System (INIS)

    The chemical separation of thorium and protactinium can be carried out by leaching most of the last one, about 95%, with aqueous HF from neutron irradiated thorium oxide. This leaching reaction la highly favored by the transformation reaction of the ThO2 material into ThF4. For both reactions, leaching and transformation, the reagents concentration, agitation speed and temperature influences were studied and the activation energies were found. (Author) 18 refs

  12. An assessment of once-through homogeneous thorium fuel economics for light water reactors

    International Nuclear Information System (INIS)

    The fuel economics of an once-through homogeneous thorium fuel concept for PWR was assessed by doing a detailed core analysis. In addition to this, the fuel economics assessment was also performed for two other ways enhancing the economic potential of thorium fuel; thorium utilization in the mixed core with uranium fuel assembly and Duplex thorium fuel concepts. As a results of fuel economics assessment, the thorium fuel cycle does not show any economic incentives in preference to uranium fuel cycle under the 18-months fuel cycle for PWR. However, the utilization of thorium is the mixed core with uranium fuel assembly and Duplex thorium fuel cycle and show superior fuel economics to uranium fuel under the longer fuel cycle scheme. The economic potential of once-through thorium fuel cycle is expected to be increased further by utilizing the Duplex thorium fuel in the mixed core with uranium fuel assembly

  13. A study of functions of 'the bank (thorium energy bank)'

    International Nuclear Information System (INIS)

    Several approaches are required in parallel for constructing a sustainable society. One of them is to fight against global warming. Nuclear power has been used for peaceful purpose because nuclear power produces electricity without emitting CO2. Though nuclear power plant has a possibility of severe accident such as the Fukushima Dai-ichi accident, its advantage is still valuable for the world. Thorium plays an important role for solving global warming. Fertile thorium can be used as nuclear fuel by support of fissionable plutonium-239 from spent uranium fuel. Plutonium-239 obtained from uranium fuel enables implementing 392 GWe of thorium nuclear power. Thorium itself is now obtained as a by-product of rare-earth mining, which is used for high-tech products including photovoltaic cell, wind-mill, and electric vehicle. However, thorium is not taken care of environmental hazard adequately so far. Both to take care of environment and to support implementation of high-tech product, and international framework of storage of thorium will be presented. (author)

  14. Determination of the total nitrate content of thorium nitrate solution with a selective electrode

    International Nuclear Information System (INIS)

    The nitrate content of thorium nitrate solutions is determined with a liquid membrane nitrate selective electrode utilizing the known addition method in 0.1 M potassium fluoride medium as ionic strength adjustor. It is studied the influence of pH and the presence of chloride, sulphate, phosphate, meta-silicate, thorium, rare earths, iron, titanium, uranium and zirconium at the same concentrations as for the aqueous feed solutions in the thorium purification process. The method is tested in synthetic samples and in samples proceeding from nitric dissolutions of thorium hidroxide and thorium oxicarbonate utilized as thorium concentrates to be purified

  15. Economics of large-scale thorium oxide production: assessment of domestic resources

    Energy Technology Data Exchange (ETDEWEB)

    Young, J.K.; Bloomster, C.H.; Enderlin, W.I.; Morgenstern, M.H.; Ballinger, M.Y.; Drost, M.K.; Weakley, S.A.

    1980-02-01

    The supply curve illustrates that sufficient amounts of thorium exist supply a domestic thorium-reactor economy. Most likely costs of production range from $3 to $60/lb ThO/sub 2/. Near-term thorium oxide resources include the stockpiles in Ohio, Maryland, and Tennessee and the thorite deposits at Hall Mountain, Idaho. Costs are under $10/lb thorium oxide. Longer term economic deposits include Wet Mountain, Colorado; Lemhi Pass, Idaho; and Palmer, Michigan. Most likely costs are under $20/lb thorium oxide. Long-term deposits include Bald Mountain, Wyoming; Bear Lodge, Wyoming; and Conway, New Hampshire. Costs approximately equal or exceed $50/lb thorium oxide.

  16. Thorium as an energy source. Opportunities for Norway

    International Nuclear Information System (INIS)

    Final Recommendations of the Thorium Report Committee: 1) No technology should be idolized or demonized. All carbon-dioxide (Co2) emission-free energy production technologies should be considered. The potential contribution of nuclear energy to a sustainable energy future should be recognized. 2) An investigation into the resources in the Fen Complex and other sites in Norway should be performed. It is essential to assess whether thorium in Norwegian rocks can be defined as an economical asset for the benefit of future generations. Furthermore, the application of new technologies for the extraction of thorium from the available mineral sources should be studied. 3) Testing of thorium fuel in the Halden Reactor should be encouraged, taking benefit of the well recognized nuclear fuel competence in Halden. 4) Norway should strengthen its participation in international collaborations by joining the EURATOM fission program and the GIF program on Generation IV reactors suitable for the use of thorium. 5) The development of an Accelerator Driven System (ADS) using thorium is not within the capability of Norway working alone. Joining the European effort in this field should be considered. Norwegian research groups should be encouraged to participate in relevant international projects, although these are currently focused on waste management. 6) Norway should bring its competence in waste management up to an international standard and collaboration with Sweden and Finland could be beneficial. 7) Norway should bring its competence with respect to dose assessment related to the thorium cycle up to an international standard. 8) Since the proliferation resistance of uranium-233 depends on the reactor and reprocessing technologies, this aspect will be of key concern should any thorium reactor be built in Norway. 9) Any new nuclear activities in Norway, e.g. thorium fuel cycles, would need strong international pooling of human resources, and in the case of thorium, a strong long

  17. Thorium as an energy source. Opportunities for Norway

    Energy Technology Data Exchange (ETDEWEB)

    2008-01-15

    Final Recommendations of the Thorium Report Committee: 1) No technology should be idolized or demonized. All carbon-dioxide (Co2) emission-free energy production technologies should be considered. The potential contribution of nuclear energy to a sustainable energy future should be recognized. 2) An investigation into the resources in the Fen Complex and other sites in Norway should be performed. It is essential to assess whether thorium in Norwegian rocks can be defined as an economical asset for the benefit of future generations. Furthermore, the application of new technologies for the extraction of thorium from the available mineral sources should be studied. 3) Testing of thorium fuel in the Halden Reactor should be encouraged, taking benefit of the well recognized nuclear fuel competence in Halden. 4) Norway should strengthen its participation in international collaborations by joining the EURATOM fission program and the GIF program on Generation IV reactors suitable for the use of thorium. 5) The development of an Accelerator Driven System (ADS) using thorium is not within the capability of Norway working alone. Joining the European effort in this field should be considered. Norwegian research groups should be encouraged to participate in relevant international projects, although these are currently focused on waste management. 6) Norway should bring its competence in waste management up to an international standard and collaboration with Sweden and Finland could be beneficial. 7) Norway should bring its competence with respect to dose assessment related to the thorium cycle up to an international standard. 8) Since the proliferation resistance of uranium-233 depends on the reactor and reprocessing technologies, this aspect will be of key concern should any thorium reactor be built in Norway. 9) Any new nuclear activities in Norway, e.g. thorium fuel cycles, would need strong international pooling of human resources, and in the case of thorium, a strong long

  18. The influence of different hydroponic conditions on thorium uptake by Brassica juncea var. foliosa.

    Science.gov (United States)

    Wang, Dingna; Zhou, Sai; Liu, Li; Du, Liang; Wang, Jianmei; Huang, Zhenling; Ma, Lijian; Ding, Songdong; Zhang, Dong; Wang, Ruibing; Jin, Yongdong; Xia, Chuanqin

    2015-05-01

    The effects of different hydroponic conditions (such as concentration of thorium (Th), pH, carbonate, phosphate, organic acids, and cations) on thorium uptake by Brassica juncea var. foliosa were evaluated. The results showed that acidic cultivation solutions enhanced thorium accumulation in the plants. Phosphate and carbonate inhibited thorium accumulation in plants, possibly due to the formation of Th(HPO4)(2+), Th(HPO4)2, or Th(OH)3CO3 (-) with Th(4+), which was disadvantageous for thorium uptake in the plants. Organic aids (citric acid, oxalic acid, lactic acid) inhibited thorium accumulation in roots and increased thorium content in the shoots, which suggested that the thorium-organic complexes did not remain in the roots and were beneficial for thorium transfer from the roots to the shoots. Among three cations (such as calcium ion (Ca(2+)), ferrous ion (Fe(2+)), and zinc ion (Zn(2+))) in hydroponic media, Zn(2+) had no significant influence on thorium accumulation in the roots, Fe(2+) inhibited thorium accumulation in the roots, and Ca(2+) was found to facilitate thorium accumulation in the roots to a certain extent. This research will help to further understand the mechanism of thorium uptake in plants.

  19. The influence of different hydroponic conditions on thorium uptake by Brassica juncea var. foliosa.

    Science.gov (United States)

    Wang, Dingna; Zhou, Sai; Liu, Li; Du, Liang; Wang, Jianmei; Huang, Zhenling; Ma, Lijian; Ding, Songdong; Zhang, Dong; Wang, Ruibing; Jin, Yongdong; Xia, Chuanqin

    2015-05-01

    The effects of different hydroponic conditions (such as concentration of thorium (Th), pH, carbonate, phosphate, organic acids, and cations) on thorium uptake by Brassica juncea var. foliosa were evaluated. The results showed that acidic cultivation solutions enhanced thorium accumulation in the plants. Phosphate and carbonate inhibited thorium accumulation in plants, possibly due to the formation of Th(HPO4)(2+), Th(HPO4)2, or Th(OH)3CO3 (-) with Th(4+), which was disadvantageous for thorium uptake in the plants. Organic aids (citric acid, oxalic acid, lactic acid) inhibited thorium accumulation in roots and increased thorium content in the shoots, which suggested that the thorium-organic complexes did not remain in the roots and were beneficial for thorium transfer from the roots to the shoots. Among three cations (such as calcium ion (Ca(2+)), ferrous ion (Fe(2+)), and zinc ion (Zn(2+))) in hydroponic media, Zn(2+) had no significant influence on thorium accumulation in the roots, Fe(2+) inhibited thorium accumulation in the roots, and Ca(2+) was found to facilitate thorium accumulation in the roots to a certain extent. This research will help to further understand the mechanism of thorium uptake in plants. PMID:25475618

  20. Thorium Nitrate Stockpile Drum Characterization Report

    International Nuclear Information System (INIS)

    Thorium nitrate (ThN) has been stored at depots for several decades and the Defense National Stockpile Center (DNSC) has evaluated options for its disposition. In support of this project, Oak Ridge National Laboratory (ORNL) has directed a characterization campaign for the ThN. The analytical results lead to the following conclusions: the ThN could be classified as LSA-1; the ThN does not contain hazardous contaminants at concentrations that would cause it to be categorized as a mixed waste if were declared to be a waste; the ThN is not required to be classfied as a Division 5.1 oxidizer per the US Dept. of Transportation definition; and, the disposal of the ThN would not be regulated by the Resource Conservation and Recovery Act and thus it could be accepted for disposal at the Nevada Test Site. This report disucsses the regulatory requirements involved with the packaging, transportation, and disposal of the ThN stockpile at the NTS. It also provides background information about the ThN stockpile, the current packaging configurations, and the current storage arrangements. The reader is also provided a description of the ThN and headspace gas sampling activities that wer conducted in 2002 and 2003 respectively. The basis for using ISO containers to transport and dispose of the ThN is discussed

  1. Study and suggestions on development of the thorium fuel cycle in China

    International Nuclear Information System (INIS)

    The features of thorium fuel cycle are analyzed and an overview of development of the thorium fuel cycle is carried out. On the basis of detailed analyses on potentials of utilizing thorium resources in all kinds of reactors, suggestions on development of the thorium fuel cycle in our country are put forward following the outlook of sustainable development of nuclear energy: (1) current reactors can't make full use of thorium resources from industrial viewpoints other than HTRs; (2) an advanced synergic fuel cycle of fast reactors and thermal reactors is suggested to utilize thorium resources; (3) more R and D efforts should be devoted on advanced and immature reactor technologies instead of the thorium utilization of these reactors; (4) currently much fundamental research work on the thorium utilization should be done. (authors)

  2. Ultra-long cycle SMART core design using thorium fuel

    International Nuclear Information System (INIS)

    A ultra-long cycle(5 years) SMART core design is examined using the thorium fuel. Most of design configurations of SMART core such as fuel loading pattern, control rod management strategy, and burnable absorber material remain unchanged but uranium fuel which is replaced with a homogeneous mixture of 20% enriched uranium and thorium. The number of burnable absorber pins of the thorium loaded SMART core was adjusted to control the excess reactivity during the cycle burnup. It was shown that mixing ratio of 40:60 of uranium fuel and thorium fuel is necessary to achieve a 5 year cycle length of SMART core. The results also show that the ultra-longer cycle SMART core satisfying all design constraints such as Fq less than 2.5, axial offset less than 0.3, keff less than 0.95 when refueling shutdown margin of 1% with most reactive control rod stuck, and ejected rod worth less than 250 pcm, are possible by using thorium fuel and absorber materials effectively

  3. Chelation therapy of thorium deposited in rat lung

    International Nuclear Information System (INIS)

    The effect of calcium diethylenetriaminepentaacetate (CaDTPA) and a siderophore analogue 3,4,3-LI(1,2-HOPO) on decorporation of small and large thorium masses (234Th 46 ng, 234Th 46 ng + 232Th 5 μg per rat) instilled into the lungs was studied. Along with repeated injections, chelating agents were administered continuously by mini-osmotic pumps over 14 d. Treatment with CaDTPA alone was partly successful in the decorporation of both thorium masses. Greater decorporation was achieved with 3,4,3-LI(1,2-HOPO) in pumps and CaDTPA in injections. In the whole body, lungs and skeleton, 23%, 24% and 24% of control radioactivity was found, respectively, for the small mass of thorium. When the large mass of thorium was instilled, only continuous infusion of 3,4,3-LI(1,2-HOPO) at low concentration efficiently prevented transfer of thorium to the skeleton (reduced to 9% of control). Both the whole body and lungs retained 50% of control radioactivity. (author)

  4. Uranium and thorium recovery in thorianite ore-preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotte, Joao V.M. [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil); Villegas, Raul A.S.; Fukuma, Henrique T., E-mail: rvillegas@cnen.gov.br, E-mail: htfukuma@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas

    2011-07-01

    This work presents the preliminary results of the studies aiming to develop a hydrometallurgical process to produce uranium and thorium concentrates from thorianite ore from Amapa State, Brazil. This process comprises two major parts: acid leaching and Th/U recovery using solvent extraction strategies. Thorianite ore has a typical composition of 60 - 70% of thorium, 8 - 10% lead and 7 - 10% uranium. Sulfuric acid leaching operational conditions were defined as follows: acid/ore ratio 7.5 t/t, ore size below 65 mesh (Tyler), 2 hours leaching time and temperature of 100 deg C. Leaching tests results showed that uranium and thorium recovery exceeded 95%, whereas 97% of lead ore content remained in the solid form. Uranium and thorium simultaneous solvent extraction is necessary due to high sulfate concentration in the liquor obtained from leaching, so the Primene JM-T primary anime was used for this extraction step. Aqueous raffinate from extraction containing sulfuric acid was recycled to the leaching step, reducing acid uptake around 60%, to achieve a net sulfuric acid consumption of 3 t/t of ore. Uranium and thorium simultaneous stripping was performed using sodium carbonate solution. In the aqueous stripped it was added sulfuric acid at pH 1.5, followed by a second solvent extraction step using the tertiary amine Alamine 336. The following stripping step was done with a solution of sodium chloride, resulting in a final solution of 23 g L-1 uranium. (author)

  5. Thorium reserves - potential for power generation, exploration and mining

    International Nuclear Information System (INIS)

    The estimated resources as on 31-03-2015 of natural uranium in India is about 1,86,000 tons compared to more than 9,60,000 tons of thorium oxide deposit. India has the world's largest deposits of thorium. The three stage Atomic Energy Program adopted by India for harnessing the nuclear energy is based on utilization of the scarcely available uranium in the country along with abundant availability of thorium, so that plutonium generated from utilization of natural uranium in power reactors using heavy water as moderator can be successfully used to breed fissile materials from thorium in most efficient manner in breeder reactors which are also capable to producing energy. Utilization of vast resources of available thorium by the breeder route will be a potential source of nuclear power for sustaining the growing energy requirement of India in long term. Thanks to the problems of greenhouse gas emissions and the depleting limited hydro-carbon resources of the country, nuclear power is likely to play a significant role in the energy production sector. The subject matter of the talk focuses on prospects and challenges in developing the process technologies of various value added products from monazite and myriad of applications in the above mentioned industry sectors which are ever evolving with time

  6. Up-gradation of technology for production of nuclear grade thorium oxide

    International Nuclear Information System (INIS)

    India with its large deposit of thorium and relatively modest deposit of uranium has drawn up its long term nuclear power generation programme based on utilisation of thorium. While the solvent extraction route presently being followed for processing of thorium is able to meet the ongoing demand for thorium for its utilisation in research programme reasonably well, the process needs to be further upgraded in view of more and more regulations on health and safety, operation and environmental impact

  7. Conceptual design of loop-in-tank type Indian molten salt breeder reactor concept

    International Nuclear Information System (INIS)

    The third stage of Indian nuclear power programme envisages use of thorium as fertile material with 233U, which is proposed to be obtained from reprocessing of spent fuel of Pu/Th based fast reactors in the later part of the second stage of the programme. In India, thorium based reactors have been designed in many configurations, from light water cooled designs to high temperature liquid metal and molten salt cooled options. Another option, which holds promise, is the molten salt-fuelled reactor, which can be configured to give significant breeding ratios. A crucial part for achieving reasonable breeding in such reactors is the need to reprocess the salt continuously, either online or in batch mode. India has recently started carrying out fundamental studies so as to arrive at a conceptual design of Indian Molten Salt Breeder Reactor (IMSBR). (author)

  8. 75 FR 71677 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2010-11-24

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... uranium and thorium processing site licensees for reimbursement under Title X of the Energy Policy Act of... requires DOE to reimburse eligible uranium and thorium licensees for certain costs of...

  9. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Science.gov (United States)

    2010-10-01

    ....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present... 49 Transportation 2 2010-10-01 2010-10-01 false Activity-mass relationships for uranium...

  10. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Science.gov (United States)

    2010-10-01

    ... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in... outer surface of the uranium or thorium is enclosed in an inactive sheath made of metal or other...

  11. 76 FR 30696 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-26

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... eligible active uranium and thorium processing site licensees for reimbursement under Title X of the Energy... requires DOE to reimburse eligible uranium and thorium licensees for certain costs of...

  12. 77 FR 3460 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2012-01-24

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... uranium and thorium processing site licensees for reimbursement under Title X of the Energy Policy Act of... requires DOE to reimburse eligible uranium and thorium licensees for certain costs of...

  13. 76 FR 24871 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-03

    ... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... from eligible active uranium and thorium processing site licensees for reimbursement under Title X of...). Title X requires DOE to reimburse eligible uranium and thorium licensees for certain costs...

  14. Technology of thorium concentrates purification and their transformation in pure nuclear products

    International Nuclear Information System (INIS)

    An experimental study for the purification of thorium concentrates by solvent extraction is presented. The product of purification is appropriate for utilization in the fabrication of nuclear reactor fuel elements. The experiments are carried out in a laboratory scale and the following operations are studied: dissolution, extraction-scrubbing, stripping-scrubbing, thorium oxalate precipitation, and thorium nitrate coagulation

  15. Adsorption of thorium from aqueous solutions by perlite.

    Science.gov (United States)

    Talip, Z; Eral, M; Hiçsönmez, U

    2009-02-01

    The use of expanded perlite for the adsorption of thorium from aqueous solution by batch technique is presented. The effects of particle size, pH of the solution, initial thorium concentration, shaking time, V/m ratio and temperature were determined. It was found that the adsorption capacity increases by the increase in the pH of the suspensions. The rate of thorium adsorption on expanded perlite was observed to be fast in the first hour of the reaction time. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models and the adsorption experiments conducted at 30 +/- 1 degrees C showed that the adsorption isotherms correlated well with the Langmuir model. From the adsorption data, thermodynamic parameters such as DeltaG(o), DeltaH(o) and DeltaS(o) were calculated as a function of temperature.

  16. Effect of the crystallinity on the leaching of thorium dioxide

    International Nuclear Information System (INIS)

    The effect of the precursor and temperature of calcination on the crystallinity and the dissolution of thorium dioxide has been studied. For a calcination temperature of 900 deg. C, the largest crystallite is obtained from the precipitation of thorium oxalate. The dissolution of crystallized ThO2 has been studied as a function of pH. High temperature crystallized ThO2 is less soluble by two order of magnitude than hydrous ThO2. We have pointed out a correlation between the crystallinity of the solid and its apparent leachability in acidic perchlorate solutions, resulting mainly in the thorium site concentration differences between solids. However, the normalized dissolution rate of crystallized ThO2 is independent on the way of synthesis of the solid. (authors)

  17. Feasibility and deployment strategy of water cooled thorium breeder reactor

    International Nuclear Information System (INIS)

    The author have studied water cooled thorium breeder reactor based on matured pressurized water reactor (PWR) plant technology for several years. Through these studies it is concluded that reduced moderated core by arranging fuel pins in a triangular tight lattice array with heavy water coolant in the primary loop by replacing original light water is appropriate for achieving sufficient breeding performance as sustainable fission system and high enough burn-up as an economical power plant. The heavy water cooled thorium reactor is feasible to be introduced by using Pu recovered from spent fuel of LWR, keeping continuity with current LWR infrastructure. This thorium reactor can be operated as sustainable energy supplier and also MA transmuter to realize future society with less long-lived nuclear waste

  18. Preparation of thorium oxide microspheres by internal gelation process

    International Nuclear Information System (INIS)

    Thorium oxide microspheres are used for the High Temperature Reactors (HTR) fuel element fabrication. One of the preparation methods is the internal gelation technique. This technique involves precipitation of hydrous thorium oxide via an hydrolytic process (internal gelation) by the dispersion of a stream of droplets of Th(NO3)4 . 4H2O solution containing an hydrolysable material. Urea is used for Th+4 complexation and hexamethylenetetramine (HMTA) for NH3 generation. The colloidal thorium is injected into a hot (95 + - 30C) oil column. The droplets are solidified as spheres by the action of in situ generated ammonia. The procedures for washing, drying, calcination and sintering of the microspheres are described as well as the physical and chemical characterization of the final product. (Author)

  19. Thorium as a Fuel for Accelerator Driven Subcritical Electronuclear Systems

    CERN Document Server

    Barashenkov, V S; Singh, V

    2000-01-01

    Neutron yield and energy production in a very large, practically infinite, uranium and thorium target-blocks irradiated by protons with energies in the range 0.1-2 GeV are studied by Monte Carlo method. Though the comparison of uranium and thorium targets shows that the neutron yield in the latter is 30-40 % less and the energy gain is approximatelly two times smaller, accelerator Driven subcritical Systems (ADS) with thorium fuel are very perspective at the bombarding energies higher than several hundreds MeV. An admixture of fissile elements U^{233}, U^{235}, Pu^{239} in the set-up gives larger neutron multiplication which in turn shows better energy amplification. It is argued that due to the practically complete burning of the fuel in such set-up there is no need of technology of conversion of the exhaust fuel.

  20. Host minerals for uranium and thorium in the Cape granite

    International Nuclear Information System (INIS)

    The uranium and thorium in Cape granite reside chiefly in trace minerals. The principle host minerals differ much from pluton to pluton. The large composite Khubus pluton in the Richterveld is composed of a central body of syenite surrounded by various types of granite. The granites are usually very low in dark minerals. According to autoradiographic results, the bulk of the uranium and thorium in the Khubus pluton is situated in the zircon, rather than in the sphene, apatite and fluorite. In many intrusives of the Cape granite suite most of the uranium is situated in a single host mineral such a zircon, xenotime, sphene or even uraninte. The most important thorium host mineral is monazite. The radio-element host mineral spectrum is unique for each different intrusive

  1. Estimating terrestrial uranium and thorium by antineutrino flux measurements.

    Science.gov (United States)

    Dye, Stephen T; Guillian, Eugene H

    2008-01-01

    Uranium and thorium within the Earth produce a major portion of terrestrial heat along with a measurable flux of electron antineutrinos. These elements are key components in geophysical and geochemical models. Their quantity and distribution drive the dynamics, define the thermal history, and are a consequence of the differentiation of the Earth. Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations. This article describes the methods and criteria to experimentally determine average concentrations of uranium and thorium in the continental crust and in the mantle by using site-specific measurements of the terrestrial antineutrino flux. Optimal, model-independent determinations involve significant exposures of antineutrino detectors remote from nuclear reactors at both a midcontinental and a midoceanic site. This would require major, new antineutrino detection projects. The results of such projects could yield a greatly improved understanding of the deep interior of the Earth.

  2. Estimating terrestrial uranium and thorium by antineutrino flux measurements

    CERN Document Server

    Dye, Stephen T

    2008-01-01

    Uranium and thorium within the Earth produce a major portion of terrestrial heat along with a measurable flux of electron antineutrinos. These elements are key components in geophysical and geochemical models. Their quantity and distribution drive the dynamics, define the thermal history, and are a consequence of the differentiation of the Earth. Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations. This research report describes the methods and criteria to experimentally determine average concentrations of uranium and thorium in the continental crust and in the mantle using site-specific measurements of the terrestrial antineutrino flux. Optimal, model-independent determinations involve significant exposures of antineutrino detectors remote from nuclear reactors at both a mid-continental and a mid-oceanic site. This would require major, new antineutrino detection projects. The results of such projects could yield a greatly improved understa...

  3. Thorium fueled high temperature gas cooled reactors. An assessment

    International Nuclear Information System (INIS)

    The use of thorium as a fertile fuel for the High Temperature Gas Cooled Reactor (HTR) instead of uranium has been reviewed. It has been concluded that the use of thorium might be beneficial to reduce the actinide waste production. To achieve a real advancement, the uranium of the spent fuel has to be recycled and the requested make-up fissile material for the fresh fuel has to be used in the form of highly-enriched uranium. A self-sustaining fuel cycle may be possible in the HTR of large core size, but this could reduce the inherent safety features of the design. (orig.)

  4. PROCESS FOR DECONTAMINATING THORIUM AND URANIUM WITH RESPECT TO RUTHENIUM

    Science.gov (United States)

    Meservey, A.A.; Rainey, R.H.

    1959-10-20

    The control of ruthenium extraction in solvent-extraction processing of neutron-irradiated thorium is presented. Ruthenium is rendered organic-insoluble by the provision of sulfite or bisulfite ions in the aqueous feed solution. As a result the ruthenium remains in the aqueous phase along with other fission product and protactinium values, thorium and uranium values being extracted into the organic phase. This process is particularly applicable to the use of a nitrate-ion-deficient aqueous feed solution and to the use of tributyl phosphate as the organic extractant.

  5. Thorium determination in water and biological materials by fission track

    International Nuclear Information System (INIS)

    As a segment of a research programme on the study of bioaccumulation of radionuclides, in animals and vegetables from Morro do Ferro, Pocos de Caldas, MG, a fission track method for the determination of low levels of thorium in environmental samples was developed as an alternative for alpha spectroscopy. The study was carried out in early alpha spectroscopy samples, containing high levels of 228 Th activity, which makes difficult the 232 Th determination. A dry way method for thorium evaluation was developed. Pieces of membrane filters, containing La F3 (Th), coupled to Makrofol detectors, were irradiated in the core of a research reactor, IEA-R1 (IPEN). (author)

  6. Introduction of Thorium in the Nuclear Fuel Cycle. Short- to long-term considerations

    International Nuclear Information System (INIS)

    Since the beginning of the nuclear era, significant scientific attention has been given to thorium's potential as a nuclear fuel. Although the thorium fuel cycle has never been fully developed, the opportunities and challenges that might arise from the use of thorium in the nuclear fuel cycle are still being studied in many countries and in the context of diverse international programmes around the world. This report provides a scientific assessment of thorium's potential role in nuclear energy both in the short to longer term, addressing diverse options, potential drivers and current impediments to be considered if thorium fuel cycles are to be pursued. (authors)

  7. Separation of thorium and uranium in nitric acid solution using silica based anion exchange resin.

    Science.gov (United States)

    Chen, Yanliang; Wei, Yuezhou; He, Linfeng; Tang, Fangdong

    2016-09-30

    To separate thorium and uranium in nitric acid solution using anion exchange process, a strong base silica-based anion exchange resin (SiPyR-N4) was synthesized. Batch experiments were conducted and the separation factor of thorium and uranium in 9M nitric acid was about 10. Ion exchange chromatography was applied to separate thorium and uranium in different ratios. Uranium could be eluted by 9M nitric acid and thorium was eluted by 0.1M nitric acid. It was proved that thorium and uranium can be separated and recovered successfully by this method.

  8. A review on the status of development in thorium-based nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Woo; Na, S. H.; Lee, Y. W.; Kim, H. S.; Kim, S. H.; Joung, C.Y

    2000-02-01

    Thorium as an alternative nuclear energy source had been widely investigated in the 1950s-1960s because it is more abundant than uranium, but the studies of thorium nuclear fuel cycle were discontinued by political and economic reasons in the 1970s. Recently, however, renewed interest was vested in thorium-based nuclear fuel cycle because it may generate less long-lived minor actinides and has a lower radiotoxicity of high level wastes after reprocessing compared with the thorium fuel cycle. In this state-of the art report, thorium-based nuclear cycle. In this state-of the art report, thorium-based nuclear fuel cycle and fuel fabrication processes developed so far with different reactor types are reviewed and analyzed to establish basic technologies of thorium fuel fabrication which could meet our situation. (author)

  9. An in-situ analysis and measurement of thorium-234, uranium isotopes in seawater

    Institute of Scientific and Technical Information of China (English)

    ZENG Xianzhang; QIU Manhua; YIN Mingduan; ZENG Wenyi; HE Jianhua; WAN Xueguo; CHEN Hengliang; LI Jing; TAN Baozeng

    2007-01-01

    A low-level β counting-α spectrum apparatus used for the detection of the β radiation of thorium-234 and α spectrum of thorium-228 simultaneously and an easy operating procedure for the enrichment, radiochemical separating, sampling and measurement of thorium-234 and uranium-238 in the ocean are developed based on the requirements of analyzing export productivity in the euphotic zone via thorium-234-uranium-238 radioactivity disequilibrium. The detecting efficiency both of β and α radiation is higher than 20%. The background of β radiation is less than 0.5 min-1, and the energy resolution of α detector is better than 1%. Total recycle ratio of thorium-234 is about 75%. Using the above apparatus and procedure, the radioactivities of dissolved thorium-234 and uranium-238, particle thorium-234 and uranium-238 in seawater of the South China Sea, the Southern Ocean and the Arctic Ocean were analyzed.

  10. A review on the status of development in thorium-based nuclear fuels

    International Nuclear Information System (INIS)

    Thorium as an alternative nuclear energy source had been widely investigated in the 1950s-1960s because it is more abundant than uranium, but the studies of thorium nuclear fuel cycle were discontinued by political and economic reasons in the 1970s. Recently, however, renewed interest was vested in thorium-based nuclear fuel cycle because it may generate less long-lived minor actinides and has a lower radiotoxicity of high level wastes after reprocessing compared with the thorium fuel cycle. In this state-of the art report, thorium-based nuclear cycle. In this state-of the art report, thorium-based nuclear fuel cycle and fuel fabrication processes developed so far with different reactor types are reviewed and analyzed to establish basic technologies of thorium fuel fabrication which could meet our situation. (author)

  11. Analytical Characterization of the Thorium Nitrate Stockpile

    Energy Technology Data Exchange (ETDEWEB)

    Mattus, CH

    2003-12-30

    For several years, Oak Ridge National Laboratory (ORNL) has been supporting the Defense Logistics Agency-Defense National Stockpile Center with stewardship of a thorium nitrate (ThN) stockpile. The effort for fiscal year 2002 was to prepare a sampling and analysis plan and to use the activities developed in the plan to characterize the ThN stockpile. The sampling was performed in June and July 2002 by RWE NUKEM with oversight by ORNL personnel. The analysis was performed by Southwest Research Institute of San Antonio, Texas, and data validation was performed by NFT, Inc., of Oak Ridge, Tennessee. Of the {approx} 21,000 drums in the stockpile, 99 were sampled and 53 were analyzed for total metals composition, radiological constituents (using alpha and gamma spectrometry), and oxidizing characteristics. Each lot at the Curtis Bay Depot was sampled. Several of the samples were also analyzed for density. The average density of the domestic ThN was found to be 1.89 {+-} 0.08 g/cm{sup 3}. The oxidizer test was performed following procedures issued by the United Nations in 1999. Test results indicated that none of the samples tested was a Division 5.1 oxidizer per Department of Transportation definition. The samples were analyzed for total metals following the U.S. Environmental Protection Agency methods SW-846-6010B and 6020 (EPA 2003) using a combination of inductively coupled plasma--atomic emission spectroscopy and inductively coupled plasma--mass spectroscopy techniques. The results were used to compare the composition of the eight Resource Conservation and Recovery Act metals present in the sample (arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver) to regulatory limits. None of the samples was found to be hazardous for toxicity characteristics. The radiological analyses confirmed, when possible, the results obtained by the inductively coupled plasma analyses. These results--combined with the historical process knowledge acquired on the material

  12. The Indian Wars Again?

    Science.gov (United States)

    Snipp, C. Matthew

    1991-01-01

    Explains history of federal-Indian relationship and changing tribal sovereignty rights. Describes treaty disputes and Indian-non-Indian conflicts in Washington, Wisconsin, and Oklahoma. Describes general nature of Indian alliances and support networks. Discusses possible roles for social scientists and social-science studies to mitigate Indian…

  13. KNOW YOUR NEVADA INDIANS.

    Science.gov (United States)

    POEHLMAN, CHARLES H.; AND OTHERS

    THIS PUBLICATION PRESENTS THE RESULTS OF A STUDY OF THE SOCIOCULTURAL BACKGROUNDS OF THE PAIUTE, WASHOE, AND SHOSHONE INDIANS OF NEVADA. INCLUDED ARE AN OUTLINE OF GENERAL PROBLEMS PERTAINING TO INDIAN EDUCATION, SOME DISTINCT CULTURAL DIFFERENCES BETWEEN THE DOMINANT NON-INDIAN SOCIETY AND THE INDIAN SOCIETY, AND THE PREHISTORIC ASPECTS OF THE…

  14. Design and evaluation of a thorium (IV) selective optode

    Energy Technology Data Exchange (ETDEWEB)

    Safavi, Afsaneh [Department of Chemistry, Faculty of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)]. E-mail: Afsaneh_safavi@yahoo.com; Sadeghi, Marzieh [Department of Chemistry, Faculty of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

    2006-05-17

    A novel optical sensor has been proposed for sensitive determination of thorium (IV) ion in aqueous solutions. The thorium sensing membrane was prepared by incorporating 4-(p-nitrophenyl azo)-pyrocatechol (NAP) as ionophore in the plasticized PVC membrane containing tributyl phosphate (TBP) as plasticizer. The membrane responds to thorium ion by changing color reversibly from yellow to red-brown in glycine buffer solution at pH 3.5. The proposed sensor displays a linear range of 8.66 x 10{sup -6}-2.00 x 10{sup -4} M with a limit of detection of 6 x 10{sup -6} M. The response time of the optode was about 8.8-12.5 min, depending on the concentration of Th (IV) ions. The selectivity of optode to Th (IV) ions in glycine buffer is good. The sensor can readily be regenerated by exposure to a solution mixture of sodium fluoride and 5-sulfosalicylic acid (dihydrate) (0.01 M each). The optode is fully reversible. The proposed optode was applied to the determination of thorium (IV) in environmental water samples.

  15. Transmutation of minor actinide using thorium fueled BWR core

    International Nuclear Information System (INIS)

    One of the methods to conduct transmutation of minor actinide is the use of BWR with thorium fuel. Thorium fuel has a specific behaviour of producing a little secondary minor actinides. Transmutation of minor actinide is done by loading it in the BWR with thorium fuel through two methods, namely close recycle and accumulation recycle. The calculation of minor actinide composition produced, weigh of minor actinide transmuted, and percentage of reminder transmutation was carried SRAC. The calculations were done to equivalent cell modeling from one fuel rod of BWR. The results show that minor actinide transmutation is more effective using thorium fuel than uranium fuel, through both close recycle and accumulation recycle. Minor actinide transmutation weight show that the same value for those recycle for 5th recycle. And most of all minor actinide produced from 5 unit BWR uranium fuel can transmuted in the 6th of close recycle. And, the minimal value of excess reactivity of the core is 12,15 % Δk/k, that is possible value for core operation

  16. Energy from thorium?! Reconnoitering a new possibility : FEA

    NARCIS (Netherlands)

    van Klinken, J

    1998-01-01

    The worldwide increasing energy consumption depends largely on fossil resources and is not sustainable. Section 1 starts with a reflection on this precarious situation as an introduction to a recently proposed possibility of a thorium-fueled sub-critical reactor driven by a proton accelerator. In co

  17. Discovery of the actinium, thorium, protactinium, and uranium isotopes

    CERN Document Server

    Fry, C

    2012-01-01

    Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  18. Controlled synthesis of thorium and uranium oxide nanocrystals.

    Science.gov (United States)

    Hudry, Damien; Apostolidis, Christos; Walter, Olaf; Gouder, Thomas; Courtois, Eglantine; Kübel, Christian; Meyer, Daniel

    2013-04-22

    Very little is known about the size and shape effects on the properties of actinide compounds. As a consequence, the controlled synthesis of well-defined actinide-based nanocrystals constitutes a fundamental step before studying their corresponding properties. In this paper, we report on the non-aqueous surfactant-assisted synthesis of thorium and uranium oxide nanocrystals. The final characteristics of thorium and uranium oxide nanocrystals can be easily tuned by controlling a few experimental parameters such as the nature of the actinide precursor and the composition of the organic system (e.g., the chemical nature of the surfactants and their relative concentrations). Additionally, the influence of these parameters on the outcome of the synthesis is highly dependent on the nature of the actinide element (thorium versus uranium). By using optimised experimental conditions, monodisperse isotropic uranium oxide nanocrystals with different sizes (4.5 and 10.7 nm) as well as branched nanocrystals (overall size ca. 5 nm), nanodots (ca. 4 nm) and nanorods (with ultra-small diameters of 1 nm) of thorium oxide were synthesised.

  19. Role of thorium in the industry advantage of atomic energy

    International Nuclear Information System (INIS)

    Based in the utilization of others fossil substances, such as plutonium and uranium 233, produzed through the thorium and natural uranium (238), it is discussed the relative merits of alternative processes: to produce U233 on Pu 239 to substitute the initial load of U235. (M.C.K.)

  20. Concentrations of uranium and thorium in bottled mineral waters

    International Nuclear Information System (INIS)

    Concentrations of uranium and thorium in commercial bottled mineral waters (81 domestic and 11 foreign products) have been analyzed using ICP-MS. Domestic bottled mineral waters exhibit very wide range of the uranium concentrations (0.1–3300 ng/L). However uranium concentrations of most samples were below 100 ng/L. There is no obvious correlation between the values of hardness and the uranium concentrations of the domestic bottled mineral waters. The uranium concentrations of foreign bottled mineral waters tended to be much higher than those of domestic ones (up to 4000 ng/L), and the values of hardness correlate roughly with the uranium concentration. It may be due to interactions between limestone and groundwater. Thorium concentrations of both domestic and foreign bottled mineral waters are typically less than 3.0 ng/L. Concentrations of uranium and thorium in bottled mineral waters were greatly lower than provisional guideline values defined by WHO. Therefore, it can be considered that there is no health risk chemically/radioactively induced by natural uranium and thorium in commercial mineral waters currently available in Japan, especially in Kyoto City. (author)

  1. Controlled synthesis of thorium and uranium oxide nano-crystals

    International Nuclear Information System (INIS)

    Very little is known about the size and shape effects on the properties of actinide compounds. As a consequence, the controlled synthesis of well-defined actinide-based nano-crystals constitutes a fundamental step before studying their corresponding properties. In this paper, we report on the non-aqueous surfactant-assisted synthesis of thorium and uranium oxide nano-crystals. The final characteristics of thorium and uranium oxide nano-crystals can be easily tuned by controlling a few experimental parameters such as the nature of the actinide precursor and the composition of the organic system (e.g., the chemical nature of the surfactants and their relative concentrations). Additionally, the influence of these parameters on the outcome of the synthesis is highly dependent on the nature of the actinide element (thorium versus uranium). By using optimised experimental conditions, monodisperse isotropic uranium oxide nano-crystals with different sizes (4.5 and 10.7 nm) as well as branched nano-crystals (overall size ca. 5 nm), nano-dots (ca. 4 nm) and nano-rods (with ultra-small diameters of 1 nm) of thorium oxide were synthesised. (authors)

  2. Helium on Venus - Implications for uranium and thorium

    Science.gov (United States)

    Prather, M. J.; Mcelroy, M. B.

    1983-01-01

    Helium is removed at an average rate of 10 to the 6th atoms per square centimeter per second from Venus's atmosphere by the solar wind following ionization above the plasmapause. The surface source of helium-4 on Venus is similar to that on earth, suggesting comparable abundances of crustal uranium and thorium.

  3. Helium on Venus: Implications for uranium and thorium

    OpenAIRE

    Prather, MJ; McElroy, MB

    1983-01-01

    Helium is removed at an average rate of 106 atoms per square centimeter per second from Venus's atmosphere by the solar wind following ionization above the plasmapause. The surface source of helium-4 on Venus is similar to that on Earth, suggesting comparable abundances of crustal uranium and thorium.

  4. Introducing advanced thorium-based fuel cycles in SA : an evolutionary approach / Maria Hendrina (Marina) du Toit

    OpenAIRE

    Du Toit, Maria Hendrina

    2013-01-01

    Past experience in several thorium fuelled research- and power reactors provides the basis and history of thorium. The material properties, fertile- and fissile isotope properties as well as the decay chain of thorium are discussed for purposes of evaluating thorium as a source of fuel. The different thorium-based fuel designs for PWR cores are discussed and resulting difficulties and solutions are outlined. The different options for each strategy are compared in terms of ad...

  5. Uranium- and thorium-bearing pegmatites of the United States

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.W.; Arengi, J.T.; Parrish, I.S.

    1980-04-01

    This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin. From an extensive literature survey and field examination of 44 pegmatite localities in the United States and Canada, the authors have compiled an index to about 300 uranium- and thorium-bearing pegmatites in the United States, maps giving location of these deposits, and an annotated bibliography to some of the most pertinent literature on the geology of pegmatites. Pegmatites form from late-state magma differentiates rich in volatile constituents with an attendant aqueous vapor phase. It is the presence of an aqueous phase which results in the development of the variable grain size which characterizes pegmatites. All pegmatites occur in areas of tectonic mobility involving crustal material usually along plate margins. Those pegmatites containing radioactive mineral species show, essentially, a similar distribution to those without radioactive minerals. Criteria such as tectonic setting, magma composition, host rock, and elemental indicators among others, all serve to help delineate areas more favorable for uranium- and thorium-bearing pegmatites. The most useful guide remains the radioactivity exhibited by uranium- and thorium-bearing pegmatites. Although pegmatites are frequently noted as favorable hosts for radioactive minerals, the general paucity and sporadic distribution of these minerals and inherent mining and milling difficulties negate the resource potential of pegmatites for uranium and thorium.

  6. Uranium- and thorium-bearing pegmatites of the United States

    International Nuclear Information System (INIS)

    This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin. From an extensive literature survey and field examination of 44 pegmatite localities in the United States and Canada, the authors have compiled an index to about 300 uranium- and thorium-bearing pegmatites in the United States, maps giving location of these deposits, and an annotated bibliography to some of the most pertinent literature on the geology of pegmatites. Pegmatites form from late-state magma differentiates rich in volatile constituents with an attendant aqueous vapor phase. It is the presence of an aqueous phase which results in the development of the variable grain size which characterizes pegmatites. All pegmatites occur in areas of tectonic mobility involving crustal material usually along plate margins. Those pegmatites containing radioactive mineral species show, essentially, a similar distribution to those without radioactive minerals. Criteria such as tectonic setting, magma composition, host rock, and elemental indicators among others, all serve to help delineate areas more favorable for uranium- and thorium-bearing pegmatites. The most useful guide remains the radioactivity exhibited by uranium- and thorium-bearing pegmatites. Although pegmatites are frequently noted as favorable hosts for radioactive minerals, the general paucity and sporadic distribution of these minerals and inherent mining and milling difficulties negate the resource potential of pegmatites for uranium and thorium

  7. Report on intercomparisons S-14, S-15, and S-16 of the determination of uranium and thorium in thorium ores

    International Nuclear Information System (INIS)

    Twenty-nine laboratories from 18 countries took part in this intercomparison, organized by the IAEA's Analytical Quality Control Service, to help laboratories engaged in this task to check the reliability of their results. An additional aim was to establish the concentrations of thorium and uranium in three large batches of thorium ores and certifying them as reference materials. The evaluation was based on 438 individual results (108 laboratory means) for thorium, and on 412 individual results (106 laboratory means) for uranium. The number of laboratory means per element and per sample varied from 34 to 38. The methods most frequently used in the determination of both elements were neutron activation analysis and radiometry. They were followed by spectrophotometry and X-ray fluorescence analysis for thorium and by fluorimetry, X-ray fluorescence analysis and spectrophotometry for uranium determination, respectively. The relative uncertainty of all computed overall medians which were used as the best estimations of true values, does not exceed +-10% and +-5% for the concentration values below and above 0.1%, respectively

  8. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    Directory of Open Access Journals (Sweden)

    P. V. Borisyuk

    2016-09-01

    Full Text Available In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  9. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    Science.gov (United States)

    Borisyuk, P. V.; Vasilyev, O. S.; Lebedinskii, Y. Y.; Krasavin, A. V.; Tkalya, E. V.; Troyan, V. I.; Habibulina, R. F.; Chubunova, E. V.; Yakovlev, V. P.

    2016-09-01

    In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  10. Accuracy of thorium cross section of JENDL-4.0 library in thorium based fuel core evaluation

    International Nuclear Information System (INIS)

    Highlights: ► Critical experiments on Th core were conducted to verify the accuracy of Th232 cross section of JENDL-4.0 library. ► Calculations are found to overestimate effective multiplication factor about (0.90 ± 0.01–0.99 ± 0.01)%. ► Comparison between measured and calculated Th sample worth reassures Th232 capture underestimation of JENDL-4.0 library. ► Th capture cross section is needed to be adjusted at thermal energy range to provide more reliable evaluation. - Abstract: Considering the importance of thorium data and concerning about the accuracy of Th232 cross section library, a series of experiments on thorium critical core with different neutron spectra has been implemented at Kyoto University Critical Assembly (KUCA). Reactivity worth of control rod and thorium sample was measured after the cores experimentally achieved critical state. In order to verify the accuracy of thorium cross section library, calculations of effective multiplication factor, control rod worth, reactivity worth of Th plates for the same core configurations were done by MVP code (Nagaya et al., 2005) using JENDL-4.0 library (Shibata et al., 2011). From the comparison between the measured and calculated results, the calculations are found to overestimate effective multiplication factor about (0.90 ± 0.01–0.99 ± 0.01)%. By comparing the measured Th sample worth with the calculated one, Th capture underestimation is reassured. Sensitive study on reactivity worth evaluation was conducted and it suggests that Th capture cross section is needed to be adjusted at thermal energy range to provide more reliable evaluation for thorium based fuel core design and safety calculation

  11. Mechanism of thorium biosorption by the cells of the soil fungal isolate Geotrichum sp. dwc-1

    International Nuclear Information System (INIS)

    In order to understand the impact of microorganisms on the fate of thorium in soils, we investigated the thorium biosorption behavior and the corresponding mechanisms by the cells of Geotrichum sp. dwc-1, one of the dominant species of fungal group isolated from 3.5 m depth soil layer in Southwest China. It was observed that fast thorium adsorption onto cells of G. sp. dwc-1 could take place, with a high distribution coefficient Kd (0.93 mL/mg) obtained, when Geotrichum sp. dwc-1and thorium concentrations were 5 g/L and 10 mg/L, respectively. The thorium biosorption behavior was dependent on the pH value, and the lower pH could disrupt cell membrane of G. sp. dwc-1. At pH 1, thorium was accumulated in the cytoplasmic region of the cells. When pH was higher than 1, thorium was adsorbed on the cell surface of G. sp. dwc-1, like in periplasmic region or in the outer membrane. FTIR study combined with biosorption experiments further indicated that the thorium distribution and binding behavior on cell surface were associated with amino, hydroxyl groups and phosphate or sulphur functional groups, and might also be governed by electrostatic interaction. Moreover, PIXE and EPBS showed that ion-exchange mechanism contributed to the thorium biosorption process, in which the tetravalent thorium ions replaced smaller counter-ions (K+, Ca2+ and Fe3+) occuring on the cell surface. (orig.)

  12. Influence of plant activity and phosphates on thorium bioavailability in soils from Baotou area, Inner Mongolia

    Energy Technology Data Exchange (ETDEWEB)

    Guo Pengran [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China); School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Jia Xiaoyu; Duan Taicheng; Xu Jingwei [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China); Chen Hangting, E-mail: guopengran@gmail.co [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China)

    2010-09-15

    Harm of thorium to living organisms is governed by its bioavailability. Thorium bioavailability in the soil-plant system of Baotou rare earth industrial area was studied using pot experiments of wheat and single extraction methods. The effects of wheat growth stage and phosphate on thorium bioavailability were also investigated. Based on extractabilities of various extraction methods (CaCl{sub 2}, NH{sub 4}NO{sub 3}, EDTA, HOAc) and correlation analysis of thorium uptake by wheat plant and extractable thorium, a mixture of 0.02 M EDTA + 0.5 M NH{sub 4}OAc (pH 4.6) was found suitable for evaluation of thorium bioavailability in Baotou soil, which could be predicted quantitatively by multiple regression models. Because of differences of wheat root activities, thorium bioavailability in rhizosphere soil was higher than in bulk soil at tillering stage, but the reverse occurred at jointing stage. Phosphate addition induced the mineralization of soluble thorium by forming stable thorium phosphate compounds, and reduced thorium bioavailability in soil.

  13. LWR First Recycle of TRU with Thorium Oxide for Transmutation and Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Andrea Alfonsi; Gilles Youinou; Sonat Sen

    2013-02-01

    Thorium has been considered as an option to uranium-based fuel, based on considerations of resource utilization (thorium is approximately three times more plentiful than uranium) and as a result of concerns about proliferation and waste management (e.g. reduced production of plutonium, etc.). Since the average composition of natural Thorium is dominated (100%) by the fertile isotope Th-232, Thorium is only useful as a resource for breeding new fissile materials, in this case U-233. Consequently a certain amount of fissile material must be present at the start-up of the reactor in order to guarantee its operation. The thorium fuel can be used in both once-through and recycle options, and in both fast and thermal spectrum systems. The present study has been aimed by the necessity of investigating the option of using reprocessed plutonium/TRU, from a once-through reference LEU scenario (50 GWd/ tIHM), mixed with natural thorium and the need of collect data (mass fractions, cross-sections etc.) for this particular fuel cycle scenario. As previously pointed out, the fissile plutonium is needed to guarantee the operation of the reactor. Four different scenarios have been considered: • Thorium – recycled Plutonium; • Thorium – recycled Plutonium/Neptunium; • Thorium – recycled Plutonium/Neptunium/Americium; • Thorium – recycled Transuranic. The calculations have been performed with SCALE6.1-TRITON.

  14. Conceptual design of Indian molten salt breeder reactor

    Indian Academy of Sciences (India)

    P K Vijayan; A Basak; I V Dulera; K K Vaze; S Basu; R K Sinha

    2015-09-01

    The third stage of Indian nuclear power programme envisages the use of thorium as the fertile material with 233U, which would be obtained from the operation of Pu/Th-based fast reactors in the later part of the second stage. Thorium-based reactors have been designed in many configurations, from light water-cooled designs to high-temperature liquid metal-cooled options. Another option, which holds promise, is the molten salt-fuelled reactor, which can be configured to give significant breeding ratios. A crucial part for achieving reasonable breeding in such reactors is the need to reprocess the salt continuously, either online or in batch mode. India has recently started carrying out fundamental studies so as to arrive at a conceptual design of Indian molten salt breeder reactor (IMSBR). Presently, various design options and possibilities are being studied from the point of view of reactor physics and thermal hydraulic design. In parallel, fundamental studies on natural circulation and corrosion behaviour of various molten salts have also been initiated.

  15. Thorium removal from aqueous solutions of Mexican erionite and X zeolite

    International Nuclear Information System (INIS)

    Thorium(IV) removal from aqueous solutions by erionite and X zeolite was investigated. The Th(IV) uptake at different thorium nitrate concentrations (from 0.25 to 25 mM) was evaluated. The thorium content in the aqueous solution was determined by neutron activation analysis. Th(IV) retained by zeolites was 1.7 and 3.7 meq/g for erionite and X zeolite. In order to explain the thorium sorption process in both zeolites, ion exchange mechanism was considered. It was found that thorium sorption behavior is strongly dependent of the type of zeolite, the separation factor for Mexican erionite was αTh(IV)Na(I) Th(IV)Na(I) ∼1, this value suggested an approximately ideal ion exchange behavior. The effect of pH on thorium sorption was also considered. (author)

  16. Biosorption of uranium and thorium by agro based biomass

    International Nuclear Information System (INIS)

    The use of low cost sorbent was investigated by evaluating the potential of three different agro based biomass designated biomass 1,11,111 respectively for the biosorption of uranium and thorium. Equilibrium and rate relationship were determined. The initial pH of the metal ion solution effected metal uptake capacity of the biomass and indicated a higher uptake of uranium in relation to thorium. Equilibrium, adsorption capacities was thus determined only for uranium and biomass III showed the highest uptake capacity. Biosorption of uranium was also studied in a packed bed continuous flow column. Metal bound could be eluted with O.2M NaHCO3. Reusability of the column was demonstrated over three cycles indicating the biosorption process for uranium removal is reversible without significant loss of binding efficiency. (author)

  17. Production and fabrication of thorium fuels at BARC

    International Nuclear Information System (INIS)

    Thorium oxide can be consolidated by conventional powder metallurgy technique of compaction and sintering. Thorium oxide is a difficult material to sinter and even at a sintering temperature of 2000degC, the density achievable is not > 80% T.D. Hence, activated sintering with the use of additives is resorted to for achieving densities > 90% T.D. Sinterability of thoria powders obtained from different compounds such as hydroxide, hydrocarbonate, tannate, oxalate etc. has been thoroughly investigated. The effect of different additives such as CaO, CaF2, MgO, Nb2O5 on the sinterability of thoria has been extensively studied. With the addition of 0.25% Nb2O5, sintering temperature can be brought down to as low as 1150deg-1200degC. High density thoria pellets have been fabricated for use in CIRUS, DHRUVA, FBTR, PHWRs and Experimental Fission/Fusion Hybrid Systems. (author). 6 refs., 8 figs

  18. First-principles study of point defects in thorium carbide

    Science.gov (United States)

    Pérez Daroca, D.; Jaroszewicz, S.; Llois, A. M.; Mosca, H. O.

    2014-11-01

    Thorium-based materials are currently being investigated in relation with their potential utilization in Generation-IV reactors as nuclear fuels. One of the most important issues to be studied is their behavior under irradiation. A first approach to this goal is the study of point defects. By means of first-principles calculations within the framework of density functional theory, we study the stability and formation energies of vacancies, interstitials and Frenkel pairs in thorium carbide. We find that C isolated vacancies are the most likely defects, while C interstitials are energetically favored as compared to Th ones. These kind of results for ThC, to the best authors' knowledge, have not been obtained previously, neither experimentally, nor theoretically. For this reason, we compare with results on other compounds with the same NaCl-type structure.

  19. Determination of dose equivalent and risk in thorium cycle

    International Nuclear Information System (INIS)

    In these report are presented the calculations of dose equivalent and risk, utilizing the dosimetric model described in publication 30 of the International Comission on Radiological Protection. This information was obtained by the workers of the thorium cycle, employed at the Praia and Santo Amaro Facilities, by assessing the quantity and concentration of thorium in the air. The samples and the number of measurements were established through design of experiments techniques, and the results were evaluated with the aid of variance analysis. The estimater of dose equivalent for internal and external radiation exposure and risk associated were compared with the maximum recommended limits. The results indicate the existence of operation areas whose values were above those limits, requiring so an improvement in the procedures and services in order to meet the requirements of the radiological protetion. (author)

  20. First-principles study of point defects in thorium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Daroca, D., E-mail: pdaroca@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, (1033) Buenos Aires (Argentina); Jaroszewicz, S. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Llois, A.M. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, (1033) Buenos Aires (Argentina); Mosca, H.O. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA, Av. General Paz 1499, (1650) San Martin, Buenos Aires (Argentina)

    2014-11-15

    Thorium-based materials are currently being investigated in relation with their potential utilization in Generation-IV reactors as nuclear fuels. One of the most important issues to be studied is their behavior under irradiation. A first approach to this goal is the study of point defects. By means of first-principles calculations within the framework of density functional theory, we study the stability and formation energies of vacancies, interstitials and Frenkel pairs in thorium carbide. We find that C isolated vacancies are the most likely defects, while C interstitials are energetically favored as compared to Th ones. These kind of results for ThC, to the best authors’ knowledge, have not been obtained previously, neither experimentally, nor theoretically. For this reason, we compare with results on other compounds with the same NaCl-type structure.

  1. Point defects in thorium nitride: A first-principles study

    Science.gov (United States)

    Pérez Daroca, D.; Llois, A. M.; Mosca, H. O.

    2016-11-01

    Thorium and its compounds (carbides and nitrides) are being investigated as possible materials to be used as nuclear fuels for Generation-IV reactors. As a first step in the research of these materials under irradiation, we study the formation energies and stability of point defects in thorium nitride by means of first-principles calculations within the framework of density functional theory. We focus on vacancies, interstitials, Frenkel pairs and Schottky defects. We found that N and Th vacancies have almost the same formation energy and that the most energetically favorable defects of all studied in this work are N interstitials. These kind of results for ThN, to the best authors' knowledge, have not been obtained previously, neither experimentally, nor theoretically.

  2. ISOLATION OF URANIUM(VI) AND THORIUM(IV) FROM AQUEOUS SOLUTIONS BY INORGANIC SORBENTS

    OpenAIRE

    Menchuk, V. V.; Perlova, N. A.

    2016-01-01

    Efficiency of use of a new sorbent on the basis of a silica gel at uranium and thorium isolation from their diluted aqueous solutions was investigated. It is shown that the investigated sorbent sorbs uranium and thorium better than a known sorbent (the silica gel). Influence of phases contact time, pH, the metal nature and solution ionic composition on the efficiency of uranium and thorium sorption process was studied. Experimentally received isotherms sorption are described by means of Langm...

  3. Sustainability Indicators for Open-Cycle Thorium-Fuelled Nuclear Energy

    OpenAIRE

    Ashley, S. F.; Fenner, R. A.; Nuttall, W. J.; Parks, Geoffrey T.

    2012-01-01

    The potential for countries which currently have a nominal nuclear energy infrastructure to adopt thorium-uranium-fuelled nuclear energy systems, using a once-through ?open? nuclear fuel cycle, has been presented by the International Atomic Energy Agency. This paper highlights Generation III and III+ nuclear energy technologies that could potentially adopt an open thorium-uranium fuel cycle and qualitatively highlights the main differences between the open thorium-uranium and open uranium fue...

  4. 3.4. Research and Development of Thorium in Nuclear Fuel -European Commission

    OpenAIRE

    Tsige-Tamirat, Haileyesus

    2012-01-01

    Thorium fuel cycles (ThFCs) have been investigated with varying intensity for many different reactor types in the past.This was motivated by the vast abundance of thorium and its ability to be used as a fertile material in most reactor types. Thorium oxide fuel possesses favorable neutronic, thermal and chemical properties that could enable higher fuel utilization, lower minor actinide production, and improved proliferation resistance. Past studies in the European Union indicated that Th...

  5. Preliminary concepts: coordinated safeguards for materials management in a thorium--uranium fuel reprocessing plant

    Energy Technology Data Exchange (ETDEWEB)

    Hakkila, E.A.; Barnes, J.W.; Dayem, H.A.; Dietz, R.J.; Shipley, J.P.

    1978-10-01

    This report addresses preliminary concepts for coordinated safeguards materials management in a typical generic thorium--uranium-fueled light-water reactor (LWR) fuels reprocessing plant. The reference facility is designed to recover thorium and uranium from first-generation (denatured /sup 235/U) startup fuels, first-recycle and equilibrium (denatured /sup 233/U) thorium--uranium LWR fuels, and to recover the plutonium generated in the /sup 238/U denaturant as well. 12 figures, 3 tables.

  6. Final purification of 233U from thorium by Dowex 50x4 in Thorex process

    International Nuclear Information System (INIS)

    The 233U product obtained after a single cycle 5% tributyl phosphate/shell sol T extraction, scrubbing and stripping often contains significant amount of thorium as impurity. Further purification is normally carried out using ion exchange. The present paper summarises the results of the studies carried out to find out the various factors responsible for the extraordinary binding of thorium ion at the exchanger site while exploring the possibility of eluting total thorium using HNO3 alone

  7. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    International Nuclear Information System (INIS)

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement

  8. Preliminary economic evaluation of thorium based fuels in PWRs

    OpenAIRE

    Du Toit, M.H.; Cilliers, A.C.

    2014-01-01

    Many studies have proven that thorium-based fuel cycles are more expensive than current uranium fuel cycles, which is confirmed in this paper as well. This research, however, goes beyond the conventional nuclear plant refueling cycle, aiming to optimize the refueling cycle in line with specific advantages realized from the thoriumbased refueling cycle. These benefits are the good thermal neutronic characteristics of fertile 232Th and fissile 233U, resulting in longer r...

  9. Thorium assessment study quarterly progress report, third quarter fiscal 1977

    Energy Technology Data Exchange (ETDEWEB)

    Spiewak, I.; Bartine, D. E.; Burns, T. J.; Cleveland, J. C.; Thomas, W. E.; White, J. R.

    1977-09-30

    The objective of the program described is to contribute to the ongoing assessment of the potential role of thorium fuel cycles for alleviating safeguards concerns. Scenarios include (1) no fuel recycle permitted, (2) fuel recycle permitted only in secure regions (''energy parks'') with denatured (chemically non-separable) fuels only outside these regions, and (3) no limits on fuel recycle. A further objective is to provide nuclear mass balance data on HTGRs required by ERDA contractors for comparative cost-benefit studies.

  10. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Daroca, D., E-mail: pdaroca@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Jaroszewicz, S. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina); Llois, A.M. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Mosca, H.O. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina)

    2013-06-15

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement.

  11. Treatment of uranium-thorium fuel at its production stage

    International Nuclear Information System (INIS)

    The possibility of removing 232U at the stage of obtaining 233U for the convenience of processing and reducing radiation dose has been analyzed in the paper. This problem is solved by the technology of obtaining 233U in extracted neutron beams in cold channels of a reactor. This technology will allow the acceleration of the implementation of the uranium-thorium fuel cycle in the current reactor technologies

  12. Spectrophotometric determination of thorium using arsenazo III in water

    International Nuclear Information System (INIS)

    A spectrophotometric determination of thorium with arsenazo III (1,8 dihidroxynaphtaline - 3,6 sulfanic acid - 2,7 bis (azo-2) - phenil argonic acid) was carried out aiming to analyse this element in water. In order to eliminate possible interferences, a coprecipitation with lantanium fluoride was used followed by an extration with 0,2 M TTA (tenoil-trifluor - aceton) / Benzen. The results showed a good agreement with the ones obtained by alfa-spectrometry. (Author)

  13. Uranium thorium dioxide fuel-cycle and economic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gale, J.D.; Spetz, S.W. [Framatome ANP, Inc., Lynchburg, Va. (United States)

    2001-07-01

    The fuel division of Framatome ANP (Advanced Nuclear Power) is performing a fuel-cycle analysis for uranium-thorium dioxide (U/Th) reactor fuel as part of a U.S. Department of Energy Nuclear Energy Research Initiative project titled, ''Advanced Proliferation Resistant, Lower Cost, Uranium-Thorium Dioxide Fuels for Light Water Reactor'', (DE-FC03-99SF21916). The objective is to evaluate the economic viability of the U/Th fuel cycle in commercial nuclear reactors operating in the U.S. This analysis includes formulating the evaluation methodology, validating the methodology via benchmark calculations, and performing a fuel-cycle analysis and corresponding economic evaluation. The APOLLO2-F computer program of Framatome ANP SCIENCE package was modified to incorporate the thorium decay chains and provide cross sections for the SCIENCE fuel-cycle analysis. A comparison and economic evaluation was made between UO{sub 2} and UO{sub 2}/ThO{sub 2} fuel cycles in a typical 193-fuel assembly pressurized water reactor using reload batch sizes corresponding to batch average discharge burnups of 50, 70, and 90 GWd/mtHM. Results show an increase in front-end costs for the UO{sub 2}/ThO{sub 2} cycles due primarily to the higher cost in separative work units for enriching the uranium to 19.5 wt% {sup 235}U. (author)

  14. Thorium biosorption by Aspergillus fumigatus, a filamentous fungal biomass

    International Nuclear Information System (INIS)

    Thorium biosorption by Aspergillus fumigatus was carried out in a batch reactor to study the effect of initial pH and metal ion concentration, contact time, biomass dose and kinetics and equilibrium Th uptake. Thorium(IV) uptake by A. fumigatus was pH dependent (pH range, 2.0-6.0) and maximum sorption was observed at pH 4.0. The uptake was rapid and the biosorption process reached equilibrium within 2 h of contact times at pH 2-4 and initial Th concentration of 50 and 100 mg/L. The kinetics data fitted well to Lagergren's pseudo-second-order rate equation (r2 > 0.99). A maximum initial sorption rate of 71.94 (mg/g min) and second-order rate constant of 7.82 x 10-2 (g/mg min) were observed at pH 4.0, 50 mg Th/L. The observed maximum uptake of thorium was 370 mg Th/g at equilibrium. Biosorption process could be well described by Langmuir isotherm in comparison to Freundlich and Temkin isotherms. Sodium bicarbonate was the most efficient desorbing reagent with desorption efficiency of more than 99%. Environmental scanning electron micrograph (ESEM) showed that the surface of the biomass after desorption was intact.

  15. Long term potential risk due to thorium mining

    International Nuclear Information System (INIS)

    As in the case of uranium, thorium extraction produces a certain amount of radioactive wastes, the so called mining residues, in which natural long-lived natural decay products are mobilized. Monazites, the most likely ores to be exploited first, in case of an extensive use of thorium as nuclear fuel, contain a certain fraction of uranium as well. One has studied potential long terms radiological impact of the residues originated from two typical monazites found in India and Italy, respectively poor an rich in uranium. In the case of the Italian monazite, uranium is supposed to be extracted at a level of 95%. For such monazites, the long term impact is completely governed by the residual uranium (presence of long-lived 238U descendants, 230Th (80,000 years) and/or 226Ra (1600 years)). However, for the two extreme cases studied here, the potential risks remain much smaller (by a factor lying between 20 to 50) than in the usual case of uranium mining. The risk due to radon is also correspondly reduced by the same factors. These significant differences between uranium and thorium mining have to be considered in view of some estimated long term real radiological impacts due to uranium residues, which could reach a value of the order of 1 mSv/year, the dose limit recommended for the public by the recent ICRP-60. (author). 7 refs, 3 figs, 3 tabs

  16. Radiochemical characterization of uranium and thorium isotopes in phosphogypsum

    International Nuclear Information System (INIS)

    Phosphogypsum is the by-product of the phosphoric acid industry and it is obtained by reacting phosphate rock with sulfuric acid. Approximately 69 million tons of this by-product have already been produced by the phosphate fertilizer industry in Brazil, whose production is 5.4 million tons per year. The accumulation of phosphogypsum, which is stockpiled and has no close destination, has become more and more problematical. The main objective of this study is to determine activity concentrations of 226Ra, 40K and uranium and thorium isotopes in phosphogypsum, which might help to find out an eventual future application for this material. A methodology has been developed and checked in order to determine 238U, 234U, 230Th, 232Th and 228Th in phosphate rock and phosphogypsum samples. This methodology is based on solvent extraction and ion exchange resins. The measurements were performed by alpha spectrometry. 226Ra, 232Th and 40K were also analysed by gamma spectrometry. The results showed that 226Ra migrates preferentially in the phosphogypsum, form 4 to 20%, and thorium concentrated about 80% in the phosphogypsum. The radioactive concentration of uranium isotopes ranged between 11 and 1700 Bq/kg. The radioactive concentration of thorium isotopes ranged between 7 and 850 Bq/kg. The concentration of 226Ra ranged between 22 and 1410 Bq/kg, and for 40K, it ranged between the detection limit and 41 Bq/kg. (author)

  17. Contributions to the thorium occupational exposure in Brazil

    International Nuclear Information System (INIS)

    There are around 15.000 workers in Brazil involved in the mining and milling processes of thorium bearing minerals. It is necessary to estimate the exposure of workers to airborne particulate containing thorium to estimate the risk associated with the inhalation of aerosols. The aims of this study were: - to develop a national cascade impactor and - to characterize the exposure of workers to airborne particulate containing Th in two plants and one industry that were chosen. Plant A and Pant B process niobium ore and industry C uses thorium nitrate to manufacture gas mantle. The national cascade impactor - ICN was developed to collect particulate in the range of 0,64 up to 19,4 μm. Its advantage over commercially available cascade impactors is the selections of particulate in the respirable and inhalable fractions of aerosol. The experimental calibration of the ICN agreed with the theoretical calibration. The results obtained with the ICN were compared to the ones obtained with other selective air samplers, in 3 plants. The particle size distribution and the Th mass concentration were determined in those plants. The size distribution of particulate containing Nb. U Zr, Pb. Fe, Y and Sr, and the elemental mass concentration was determined. A group of workers in installations B and C were also monitored through bioassay analysis of Th excreted in urine and feces. Air and bioassay results have shown that the systemic incorporation of Th is not significant. (author)

  18. Investigation of the thorium content in human tissues

    International Nuclear Information System (INIS)

    The content of natural alpha-emitting isotopes of thorium (Th-238, 230, and 232) have been determined in 22 sets of human tissue samples obtained at autopsy from Grand Junction, Colorado and 10 sets from Washington, DC. Lung, pulmonary lymph nodes, liver, kidney and bone were obtained for each case. Personal data for each individual's age, sex, smoking history, and occupation were obtained whenever possible. Radiochemical analysis was performed after tissue digestion, by solvent extraction, and electrodeposition, followed by solid state alpha spectrometric measurements using Si(Li) surface barrier detectors. Thorium-230 and 232 are distributed similarly in the body with the major fraction of the body burden present in bone (70%) followed by lung (20%) and lymph nodes (7%). Thorium-228 is found primarily in the skeleton (95%). For all isotopes, no significant difference was found between the concentration in tissue of smokers and non-smokers. The ratio of Th-230/232 in Colorado tissues was comparable to that of controls (Washington, DC) and probably reflects the relative geochemical abundance of the isotopes in local soils

  19. Age dependence of natural uranium and thorium concentrations in bone.

    Science.gov (United States)

    Larivière, Dominic; Packer, Ana Paula; Marro, Leonora; Li, Chunsheng; Chen, Jing; Cornett, R Jack

    2007-02-01

    The age dependence of the natural concentration of uranium and thorium in the skeleton was investigated using human vertebrae bone collected from two Canadian locations (Winnipeg, Manitoba, and Regina, Saskatchewan). The concentration of both radioelements in digested ashed bone samples was determined using sector-field inductively coupled plasma mass spectrometry. The geometric means for uranium level in bones showed a significant statistical difference between the two locations studied. Similarly for thorium, a statistical difference was observed, although this difference was considered marginal. The thorium concentration differed only marginally with respect to age group, indicating that its behavior in the body could be age-independent. Conversely, the uranium level in bones was found to change for the age groups tested, an indication of age-specific deposition. The age profile for uranium was comparable to the calcium turn-over rate, indicating that uranium deposition is probably, in part, dictated by this metabolic process, showing the role of present uptake into the uranium concentration in bones for populations exposed to significant uranium intake. PMID:17220713

  20. Modified anion-exchange method for determination of thorium in uranium based materials

    International Nuclear Information System (INIS)

    This paper details a modified anion-exchange method for estimation of thorium in uranium based samples like uranium dioxide powders, pellets and uranyl nitrate solutions. The method involves separation of thorium from uranium from 3M commercial grade HCl containing 15% NaCl through an anion-exchange resin. The uranium free effluent containing the analyte(thorium) is determined spectrophotometrically by exploiting absorption of the thorium-arsenazo III complex at 660 nm. The method has a precision of about ±2% at 50 ppm level. (author). 3 refs., 1 tab

  1. Production of actinium, thorium and radium isotopes from natural thorium irradiated with protons up to 141 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Ermolaev, S.V.; Zhuikov, B.L.; Kokhanyuk, V.M.; Matushko, V.L. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Nuclear Research; Kalmykov, S.N. [Lomonosov Moscow State Univ., Moscow (Russian Federation). Chemistry Dept.; Aliev, R.A. [Lomonosov Moscow State Univ., Moscow (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Tananaev, I.G.; Myasoedov, B.F. [Russian Academy of Sciences, Moscow (Russian Federation). A.N. Frumkin Inst. of Physical Chemistry and Electrochemistry

    2012-07-01

    Cross sections of {sup 225}Ac, {sup 227}Ac, {sup 227}Th and {sup 228}Th in thorium-232 targets irradiated with protons in the energy range 21-141 MeV have been measured. Based on these data, production yields of {sup 225}Ac and {sup 223}Ra in thick thorium targets have been calculated. It is possible to produce in proton energy range 60-140 MeV about 96 GBq (2.6 Ci) {sup 225}Ac per 10-d irradiation with 100 {mu}A proton beam current and 10-d decay, and much higher amount of {sup 223}Ra. The impurities of {sup 227}Ac and {sup 224}Ra are important and need to be assessed for further medical applications. (orig.)

  2. Application of EDRXF technique for the determination of uranium and thorium in beach sand minerals

    International Nuclear Information System (INIS)

    Zircon is a naturally occurring mineral and is available in many locations all over the world, This mineral usually contains U and Th at about 100-500 μg/g. Naturally occurring TiO2, containing minerals, rutile and ilmenite have small quantities of associated uranium. Natural rutile may contain upto 10% iron and upto 500 μg/g of uranium. Since the availability of rutile in nature is limited, ilmenite is used as raw material for producing synthetic rutile. In India, from monazite, thorium is separated by Indian Rare Earths Ltd., wherein uranium is a bye product. Since rutile is of importance to the gemstone markets, this is also produced from ilmenite ore. Roasting, reduction and leaching processes are important steps for removal of iron economically and efficiently from ilmenite ore during the production of synthetic rutile. We have developed a method to determine U and Th in zircon, using synthetic powder standards of ZrO2, containing U and Th in the range of 50 to 1000 μg/g. The limits of detection for U and Th were determined to be 200 and 100 μg/g respectively. Three zircon ore samples from different locations in India were analyzed for uranium and thorium using the method. The standardized method can be used for fast determination U and Th in zircon samples non-destructively with a precision of 10-20 %. Further another method was developed for the determination of uranium in rutile. Since iron and chromium are among the other impurities co-existing with U in rutile, these analytes have been included in the method. Synthetic standards containing U at 200-10,000 μg/g and Fe, Cr at 100- 2000 μg/g level were prepared and the spectrometer was calibrated using these standards. Two synthetic samples were analyzed using this method to evaluate the method for its reliability and reproducibility. In the present talk, details of these studies will be discussed. Moreover the work carried out on the determination of U/Th in sand minerals by other international

  3. Thorium and uranium carbide cluster cations in the gas phase: similarities and differences between thorium and uranium.

    Science.gov (United States)

    Pereira, Cláudia C L; Maurice, Rémi; Lucena, Ana F; Hu, Shuxian; Gonçalves, António P; Marçalo, Joaquim; Gibson, John K; Andrews, Lester; Gagliardi, Laura

    2013-10-01

    Laser ionization of AnC4 alloys (An = Th, U) yielded gas-phase molecular thorium and uranium carbide cluster cations of composition An(m)C(n)(+), with m = 1, n = 2-14, and m = 2, n = 3-18, as detected by Fourier transform ion-cyclotron-resonance mass spectrometry. In the case of thorium, Th(m)C(n)(+) cluster ions with m = 3-13 and n = 5-30 were also produced, with an intriguing high intensity of Th13C(n)(+) cations. The AnC13(+) ions also exhibited an unexpectedly high abundance, in contrast to the gradual decrease in the intensity of other AnC(n)(+) ions with increasing values of n. High abundances of AnC2(+) and AnC4(+) ions are consistent with enhanced stability due to strong metal-C2 bonds. Among the most abundant bimetallic ions was Th2C3(+) for thorium; in contrast, U2C4(+) was the most intense bimetallic for uranium, with essentially no U2C3(+) appearing. Density functional theory computations were performed to illuminate this distinction between thorium and uranium. The computational results revealed structural and energetic disparities for the An2C3(+) and An2C4(+) cluster ions, which elucidate the observed differing abundances of the bimetallic carbide ions. Particularly noteworthy is that the Th atoms are essentially equivalent in Th2C3(+), whereas there is a large asymmetry between the U atoms in U2C3(+).

  4. Band structure and decay channels of thorium-229 low-lying isomeric state for ensemble of thorium atoms adsorbed on calcium fluoride

    International Nuclear Information System (INIS)

    The results are presented on the study of the electronic structure of thorium atoms adsorbed by the liquid atomic layer deposition from aqueous solution of thorium nitrate on the surface of CaF2. The chemical state of the atoms and the change of the band structure in the surface layers of Th/CaF2 system on CaF2 substrate were investigated by XPS and REELS techniques. It was found that REELS spectra for Th/CaF2 system include peaks in the region of low energy losses (3-7 eV) which are missing in the similar spectra for pure CaF2. It is concluded that the presence of the observed features in the REELS spectra is associated with the chemical state of thorium atoms and is caused by the presence of uncompensated chemical bonds at the Th/CaF2 interface, and, therefore, by the presence of unbound 6d- and 7s-electrons of thorium atoms. Assuming the equivalence of the electronic configuration of thorium-229 and thorium-232 atoms, an estimate was made on the time decay of the excited state of thorium-229 nuclei through the channel of the electron conversion. It was found that the relaxation time is about 40 μs for 6d-electrons, and about 1 μs for 7s-electrons. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium purification pilot plant

    International Nuclear Information System (INIS)

    Brazil has a long tradition in thorium technology, from mineral dressing (monazite) to the nuclear grade thorium compounds. The estimate reserves are 1200,000. ton of ThO2. As a consequence from the work of thorium purification pilot plant at Instituto de Pesquisas Energeticas e Nucleares-CNEN/IPEN-SP, about 25 ton of a sludge containing thorium and rare earths was accumulated. It comes as a raffinate and washing solutions from thorium solvent extraction. This sludge, a crude hydroxide named RETOTER contains thorium, rare earths and minor impurities including the radiogenic lead-208, with abundance 88.34 %. This work discusses the results of the studies and main parameters for its recovery by anionic ion exchange technique in the hydrochloric system. The isotope abundance of this lead was analyzed by high resolution mass spectrometer (ICPMS) and thermoionic mass spectrometer (TIMS) and the data was used to calculate the thermal neutron capture cross section. The value of σγ0 = 14.6±0.7 mb was found, quite different from the σγ0 = 174.2 ± 7.0 mb measure cross section for the natural lead. Preliminary study for the thorium and rare earths separation and recovery was discussed as well. (author)

  6. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium nitrate purification pilot plant

    International Nuclear Information System (INIS)

    Brazil has a long tradition in thorium technology, from mineral dressing (monazite) to the nuclear grade thorium compounds. The estimate reserves are 1200,000. ton of ThO2. As a consequence from the work of thorium purification pilot plant at Instituto de Pesquisas Energeticas e Nucleares-CNEN/SP, about 25 ton of a sludge containing thorium and rare earths was accumulated. It comes as a raffinate and washing solutions from thorium solvent extraction. This sludge, a crude hydroxide named RETOTER contains thorium, rare earths and minor impurities including the radiogenic lead-208, with abundance 88.34 %. This work discusses the results of the studies and main parameters for its recovery by anionic ion exchange technique in the hydrochloric system. The isotope abundance of this lead was analyzed by high resolution mass spectrometer (ICPMS) and thermoionic mass spectrometer (TIMS) and the data was used to calculate the thermal neutron capture cross section. The value of s?o = 14.6 +/- 0.7 mb was found, quite different from the s?o = 174.2 +/- 7.0 mb measure cross section for the natural lead. Preliminary study for the thorium and rare earths separation and recovery was discussed as well. (author)

  7. Indianization of psychiatry utilizing Indian mental concepts.

    Science.gov (United States)

    Avasthi, Ajit; Kate, Natasha; Grover, Sandeep

    2013-01-01

    Most of the psychiatry practice in India is guided by the western concepts of mental health and illness, which have largely ignored the role of religion, family, eastern philosophy, and medicine in understanding and managing the psychiatric disorders. India comprises of diverse cultures, languages, ethnicities, and religious affiliations. However, besides these diversities, there are certain commonalities, which include Hinduism as a religion which is spread across the country, the traditional family system, ancient Indian system of medicine and emphasis on use of traditional methods like Yoga and Meditation for controlling mind. This article discusses as to how mind and mental health are understood from the point of view of Hinduism, Indian traditions and Indian systems of medicine. Further, the article focuses on as to how these Indian concepts can be incorporated in the practice of contemporary psychiatry. PMID:23858244

  8. Development of gamma spectrometric method for the determination of thorium in phosphoric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Mirashi, N.N.; Chaudhury, S.; Aggarwal, S.K. [Fuel Chemistry Div., Bhabha Atomic Research Centre, Mumbai (India)

    2010-07-01

    Gamma spectrometric determination of thorium in sintered thoria dissolved in strong phosphoric acid was studied using a high purity germanium (HPGe) detector. {sup 232}Th was determined using the highly abundant (27%) gamma ray (911.4 keV) emitted by its daughter {sup 228}Ac. The count rates in peak regions were plotted against the amount of thorium present in thorium nitrate working standard solution to obtain a calibration curve and the extent of thoria dissolved in 88% phosphoric acid was determined. Further studies on determination of thorium were carried out using thorium phosphate solutions, instead of using thorium nitrate working standard solutions. The solution of thorium phosphate obtained after quantitative dissolution of thoria in 88% phosphoric acid was also found to give a linear calibration curve at 911.4 keV. Using the calibration curves, expected count rates for thorium in sintered thoria dissolved in 88% phosphoric acid were calculated and were in good agreement ({+-}3%) with the observed count rates. (orig.)

  9. Separation of thorium ions from wolframite and scandium concentrates using graphene oxide.

    Science.gov (United States)

    Jankovský, Ondřej; Sedmidubský, David; Šimek, Petr; Klímová, Kateřina; Bouša, Daniel; Boothroyd, Chris; Macková, Anna; Sofer, Zdeněk

    2015-10-14

    The separation of rare metals from the ores and commercially available compounds is an important issue due to the need of their high purity in advanced materials and devices. Important examples of two highly important elements that co-exist in the ores are scandium and thorium. Scandium containing ores and consequently also commercially available scandium compounds often contain traces of thorium which is very difficult to separate. We used graphene oxide for the selective sorption of thorium ions from scandium and thorium mixtures originating from the mined ores as well as from commercially available scandium salts. Our results showed that graphene oxide has an extreme affinity towards thorium ions. After the sorption process the graphene oxide contained over 20 wt% of thorium while the amount of scandium sorbed on GO was very low. This phenomenon of high sorption selectivity of graphene oxide can be applied in industry for the purification of various chemicals containing scandium and for separation of thorium containing mixtures. Alternatively, this methodology can be used for preconcentration of thorium from low-grade ores and its further use in the new generation of nuclear reactors. PMID:26352806

  10. Atomic Energy Control Board and its role in the regulation of uranium and thorium mines

    International Nuclear Information System (INIS)

    Laws governing the Atomic Energy Control Board (AECB), its structure and functions is described in the context of the Board's role in uranium and thorium mining. The licensing and compliance procedures are described as they pertain to the objectives of the AECB in protecting workers, the public and the environment during construction, operating and closure of uranium and thorium mining and milling facilities. (OT)

  11. Critical review of analytical techniques for safeguarding the thorium-uranium fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Hakkila, E.A.

    1978-10-01

    Conventional analytical methods applicable to the determination of thorium, uranium, and plutonium in feed, product, and waste streams from reprocessing thorium-based nuclear reactor fuels are reviewed. Separations methods of interest for these analyses are discussed. Recommendations concerning the applicability of various techniques to reprocessing samples are included. 15 tables, 218 references.

  12. On the development of fast breeder reactors and the use of thorium in Brazil

    International Nuclear Information System (INIS)

    This work presents a discussion on the possibility of construction of fast breeder reactors in Brazil. It is specially concerned with the use of thorium which is abundant in our country. The main advantages of this projects are: develop fuel and reactor technology in Brazil, increase thorium research, demonstrate the safety of LMFBR and promote its public acceptance. (A.C.A.S.)

  13. Spent fuel characteristics analysis for thorium-uranium breeding recycle in PWRs

    International Nuclear Information System (INIS)

    Spent fuel characteristics analyses of thorium-based fuel were investigated using ORIGEN-S code compared with uranium-based fuel. Such parameters as radio- activity, radiotoxicity, decay heat, and gamma ray were considered. Relative results in this work could provide some reference information for storage, reprocessing and disposal of thorium-based spent fuel. Four type fuels, thorium-based fuel U3ThOX (mixed reactor grade 233U-thorium oxide), PuThOX (mixed reactor grade plutonium-thorium oxide), uranium-based fuel UOX (uranium oxide) and MOX (mixed reactor grade plutonium-uranium oxide), on the basis of core designs for thorium-uranium breeding recycle in PWRs were investigated. The calculated results show that: 1) Due to extremely low content of transuranic nuclides, the radiotoxicity of U3ThOX is dramatically lower than that of three other types of spent fuel in 1000 years after discharge; 2) In thorium-based spent fuel the intensity of gamma ray near 2.6 MeV mainly generated by 208Tl in 232U decay chain is much stronger than that in uranium-based fuel. The intensity of γ ray near 2.6 MeV reaches a local peak in about 10 years after discharge when the reprocessing should not be performed for thorium-based spent fuel. (authors)

  14. 78 FR 21352 - Update on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2013-04-10

    ... on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY... reimbursement for cleanup work performed by licensees at eligible uranium and thorium processing sites in... licensees of eligible uranium and thorium processing sites. If licensees submit claims in FY 2013,...

  15. 78 FR 62649 - Indian Gaming

    Science.gov (United States)

    2013-10-22

    ... activities on Indian lands. The Compact between the State of California and the North Fork Rancheria of Mono... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... Compact between the North Fork Rancheria of Mono Indians and the State of California taking effect....

  16. 76 FR 42722 - Indian Gaming

    Science.gov (United States)

    2011-07-19

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Assistant... of the Indian Gaming Regulatory Act of 1988 (IGRA), Public Law 100-497, 25 U.S.C. 2710, the...

  17. 75 FR 61511 - Indian Gaming

    Science.gov (United States)

    2010-10-05

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant Secretary... section 11 of the Indian Gaming Regulatory Act of 1988 (IGRA), Public Law 100-497, 25 U.S.C. 2710,...

  18. 75 FR 38834 - Indian Gaming

    Science.gov (United States)

    2010-07-06

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant...: Under Section 11 of the Indian Gaming Regulatory Act of 1988 (IGRA), Public Law 100-497, 25 U.S.C....

  19. 76 FR 165 - Indian Gaming

    Science.gov (United States)

    2011-01-03

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... the Menominee Indian Tribe of Wisconsin (``Tribe'') and the State of Wisconsin Gaming Compact of 1992... CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant...

  20. Potential of Melastoma malabathricum as bio-accumulator for uranium and thorium from soil

    Science.gov (United States)

    Saat, Ahmad; Kamsani, Ain Shaqina; Kamri, Wan Nur Aina Nadzira; Talib, Nur Hasyimah Mat; Wood, Ab Khalik; Hamzah, Zaini

    2015-04-01

    Uranium and Thorium are naturally occuring radionuclides. However, due to anthropogenic activities in some locations their concentrations in the soils could be elevated. This study explores the potential of Melastoma malabathricum (locally known as `pokok senduduk') as bio-accumulator of uranium and thorium from soils of three different study areas, namely former tin mining, industrial and residential/commercial areas in Peninsular Malaysia. The study found elevated concentrations of uranium and thorium in former tin mining soils as compared to natural abundance. However in industral and residential/commercial areas the concentrations are within the range of natural abundance. In terms of transfer factor (TF), in ex-mining areas TF > 1 for uranium in the leaf, stem and roots, indicating accumulation of uranium from soil. However for thorium TF uranium and thorium were observed. The results indicated the potential of Melastoma malabathricum to be used as bio-accumulatior of uranium, especially in areas of elevated concentration.

  1. Effect of mineral and organic fertilizers on uptake of uranium and thorium by cotton and wheat

    International Nuclear Information System (INIS)

    The effects of large applications of fertilizers on the uptake of uranium and thorium by cotton and wheat from soils containing small amounts of natural radionuclides were studied. The uranium content of cotton plant parts decreased by a factor of 2.9 and that of thorium by a factor of 3.8; the uptake of uranium in wheat grain was less than the control by a factor of 1.4 and that of thorium by a factor of 2.6. Complete mineral fertilizer had a greater effect on radionuclide uptake than individual applications of mineral nutrients. The smallest uptake of uranium and thorium by cotton resulted from combined use of complete mineral fertilizer and manure. Fertilizer application altered the relative amounts of water-soluble, exchangeable, acid-soluble and fixed forms of the radionuclides in the soil. Phosphorus fertilizers decreased the exchangeable thorium fraction by 20%, and, in combination with manure, by 40%

  2. Concentrations of Uranium,Thorium and Potassium in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Thunholm, Bo; Linden, Anders H.; Gustafsson, Bosse [Geological Survey of Sweden, Uppsala (Sweden)

    2005-04-01

    This report is largely a result of the Swedish contribution to an IAEA co-ordinated research programme (CRP) on the use of selected safety indicators in the assessment of radioactive waste disposal. The CRP was focusing on the assessment of the longterm safety of radioactive waste disposal by means of additional safety indicators based on data from natural systems with emphasis on description of existing data on radioactive elements and radionuclides. A major part of the work was focused on collecting data on geophysics as well as geochemistry and groundwater chemistry; mainly uranium (U), thorium (Th) and potassium (K). Data were interpreted resulting in maps and statistical description.

  3. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  4. Natural intake and excretion of thorium and uranium

    International Nuclear Information System (INIS)

    The natural content of the isotopes 238Th, 230Th and 232Th in faeces as well as 234U, 235U and 238U in drinking-water has been investigated by means of α-spectroscopy. The averaged total activity of thorium in faeces has been found to be 56,6 mBq per daily excretion, the activity of uranium in drinking water is reported to be 11.3 mBq/l. The results are in comparison with the existing data from Germany, but different to international suppositions as in UNSCEAR or ICRP 23. (orig.)

  5. Conversion ratio in epithermal PWR, in thorium and uranium cycle

    International Nuclear Information System (INIS)

    Results obtained for the conversion ratio in PWR reactors with close lattices, operating in thorium and uranium cycles, are presented. The study of those reactors is done in an unitary fuel cell of the lattices with several ratios V sub(M)/V sub(F), considering only the equilibrium cycles and adopting a non-spatial depletion calculation model, aiming to simulate mass flux of reactor heavy elements in the reactor. The neutronic analysis and the cross sections generation are done with Hammer computer code, with one critical apreciation about the application of this code in epithermal systems and with modifications introduced in the library of basic data. (E.G.)

  6. On thorium and plutonium cocrystallization with calcium oxalate

    International Nuclear Information System (INIS)

    Study of possibility of 239Pu and 234Th concentration from bone ashe (calcium phosphate) hydrochloric acid solutions by coprecipitation with nonisotopic medium (CaC2O4) for their further radiometry or alpha-spectrometry is carried out. Thorium and plutonium distribution coefficients in calcium oxalate precipitate - solution system, as well as coefficients of Th and Pu cocrystallization with CaC2O4 and cocrystallization type are determined. Possibility of Pu and Th concentration from bone tissue solutions is demonstrated on small oxalate amount containing 25% of Ca total amount in bone tissue

  7. Photon attenuation properties of some thorium, uranium and plutonium compounds

    International Nuclear Information System (INIS)

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  8. Origin of Thorium/Uranium Variations in Carbonaceous Chondrites

    OpenAIRE

    Goreva, J. S.; Burnett, D. S.

    2000-01-01

    Thorium-, U-, and Pb-isotopic analyses of a wide variety of planetary materials show that Th/U ratio (by weight) varies from 3.5 to 4.2. It is generally believed that chondritic meteorites contain refractory lithophile elements in a relative proportions close to solar, i.e., CI chondrites [1]. Surprisingly, a number of analyses of different types of carbonaceous chondrites show a large (at least a factor of 3) scatter in Th/U measurements [2]. The widest spread in Th/U is observed in the most...

  9. Chemical Speciation of Thorium in Marine Biogenic Particulate Matter

    OpenAIRE

    Katsumi Hirose

    2004-01-01

    Concentrations of particulate thorium in seawater were determined together with the strong organic ligand (SOL) and uranium in particulate matter (PM). The concentrations of particulate Th in surface waters of the western North Pacific and the Sea of Japan ranged from 0.05 to 1.5 pM (1 x 10−12 M), and showed relatively large temporal and spatial variations. In order to chemically characterize the particulate Th in seawater, the relationship between particulate Th and SOL concentrations in sur...

  10. Configurational analysis of uranium-doped thorium dioxide

    Science.gov (United States)

    Shields, A. E.; Ruiz-Hernandez, S. E.; de Leeuw, N. H.

    2015-04-01

    While thorium dioxide is already used industrially in high temperature applications, more insight is needed about the behaviour of the material as part of a mixed-oxide (MOX) nuclear fuel, incorporating uranium. We have developed a new interatomic potential model, commensurate with a prominent existing UO2 potential, to conduct configurational analyses of uranium-doped ThO2 supercells. Using the GULP and Site Occupancy Disorder (SOD) computational codes, we have analysed the distribution of low concentrations of uranium in the bulk material, but have not observed the formation of uranium clusters or a single dominant configuration.

  11. Mechanism of thorium biosorption by the cells of the soil fungal isolate Geotrichum sp. dwc-1

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Congcong; Feng, Su [Sichuan Univ., Chengdu (China). Key Laboratory of Biological Resource and Ecological Environment; Li, Xiaolong [Sichuan Univ., Chengdu (China). Key Laboratory of Radiation Physics and Technology; and others

    2014-04-01

    In order to understand the impact of microorganisms on the fate of thorium in soils, we investigated the thorium biosorption behavior and the corresponding mechanisms by the cells of Geotrichum sp. dwc-1, one of the dominant species of fungal group isolated from 3.5 m depth soil layer in Southwest China. It was observed that fast thorium adsorption onto cells of G. sp. dwc-1 could take place, with a high distribution coefficient K{sub d} (0.93 mL/mg) obtained, when Geotrichum sp. dwc-1and thorium concentrations were 5 g/L and 10 mg/L, respectively. The thorium biosorption behavior was dependent on the pH value, and the lower pH could disrupt cell membrane of G. sp. dwc-1. At pH 1, thorium was accumulated in the cytoplasmic region of the cells. When pH was higher than 1, thorium was adsorbed on the cell surface of G. sp. dwc-1, like in periplasmic region or in the outer membrane. FTIR study combined with biosorption experiments further indicated that the thorium distribution and binding behavior on cell surface were associated with amino, hydroxyl groups and phosphate or sulphur functional groups, and might also be governed by electrostatic interaction. Moreover, PIXE and EPBS showed that ion-exchange mechanism contributed to the thorium biosorption process, in which the tetravalent thorium ions replaced smaller counter-ions (K{sup +}, Ca{sup 2+} and Fe{sup 3+}) occuring on the cell surface. (orig.)

  12. Comparison of the radiological hazard of thorium and uranium spent fuels from VVER-1000 reactor

    International Nuclear Information System (INIS)

    Thorium fuel is considered as a viable alternative to the uranium fuel used in the current generation of nuclear power plants. Switch from uranium to thorium means a complete change of composition of the spent nuclear fuel produced as a result of the fuel depletion during operation of a reactor. If the Th–U fuel cycle is implemented, production of minor actinides in the spent fuel is negligible. This is favourable for the spent fuel disposal. On the other hand, thorium fuel utilisation is connected with production of 232U, which decays via several alpha decays into a strong gamma emitter 208Tl. Presence of this nuclide might complicate manipulations with the irradiated thorium fuel. Monte-Carlo computation code MCNPX can be used to simulate thorium fuel depletion in a VVER-1000 reactor. The calculated actinide composition will be analysed and dose rate from produced gamma radiation will be calculated. The results will be compared to the reference uranium fuel. Dependence of the dose rate on time of decay after the end of irradiation in the reactor will be analysed. This study will compare the radiological hazard of the spent thorium and uranium fuel handling. - Highlights: • Spent thorium and uranium fuel composition in VVER-1000 was calculated by MCNPX. • Important nuclide 208Tl is not included in the thorium spent fuel composition. • There are large differences in activity of actinides between spent Th and U fuels. • Dose rate from spent thorium fuel is increasing during 50 years of decay. • 208Tl in spent thorium fuel increased the dose rate by several percent

  13. Indian concepts on sexuality

    OpenAIRE

    Chakraborty, Kaustav; Thakurata, Rajarshi Guha

    2013-01-01

    India is a vast country depicting wide social, cultural and sexual variations. Indian concept of sexuality has evolved over time and has been immensely influenced by various rulers and religions. Indian sexuality is manifested in our attire, behavior, recreation, literature, sculptures, scriptures, religion and sports. It has influenced the way we perceive our health, disease and device remedies for the same. In modern era, with rapid globalization the unique Indian sexuality is getting diffu...

  14. Determination of rare earth elements, yttrium, uranium and thorium in ilmenite samples by ICP-MS

    International Nuclear Information System (INIS)

    Ilmenite is a principal mineral of titanium and is used mainly in the production of titanium dioxide pigment. Determination of trace elements in ilmenite samples constitutes a challenge to the analyst as the highly Iron-Titanium rich matrix poses a lot of problems, both during the sample dissolution stage as well as during the instrumental determination stage. Solution inductively coupled plasma mass spectrometry (ICP-MS) has emerged as a powerful and sensitive technique that has been successfully used for the accurate direct determination of several trace elements in geological materials. But, even with ICP-MS, direct determination of trace constituents in complex mineral matrices is extremely difficult because of the constraints on total dissolved salt (TDS) levels of sample solutions and other mass spectroscopic and non-mass spectroscopic interferences. Therefore, in the present work, the extent of interference on all rare-earth elements (REEs), yttrium, uranium and thorium due to the iron matrix has been assessed at a single set of operating conditions for different amounts of iron taken, using solutions of magnetite ore 'SARM 12' (containing 95.3% Fe2O3) and the accuracy of the results obtained have been evaluated. Some selected Indian ilmenite samples have been analysed by ICP-MS after sample dissolution using a mixture of hydrofluoric, hydrochloric and sulphuric acids and the values obtained compared with those obtained by ICP-OES after separation of the iron matrix. Though a number of international ilmenite reference materials are available, certified or even proposed values are available only for a very few elements in them. Two ilmenite reference materials (IGS 31 and SARM 59) have also been analysed by ICP-MS and usable values have been proposed in this paper. The % RSD for all the estimated elements varied from 3.0% to 15.0% at different concentration levels. (author)

  15. Extraction of trace thorium from hydrochloric acid media by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-Fan; YUAN Shuang-Gui; XU Yan-Bing; XIAO Yong-Hou; XIONG Bing

    2003-01-01

    The paper describes the solvent extraction of trace thorium from hydrochloric acid media by1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) using a radioactive tracer technique. The percent extraction ofthorium was studied as a function of acidity, PMBP concentration and equilibrium time. The back-extraction behaviorof thorium from the organic phase was also tested. Separation of thorium was performed from fission products pro-duced in 14 MeV neutron bombardment of natural uranium by employing the PMBP extraction procedure. Thegamma-ray spectra of the separated thorium fractions show that thorium can be separated from most of fission prod-ucts and a large amount of uranium.

  16. Thorium (IV) toxicity of green microalgae from Scenedesmus and Monoraphidium genera

    International Nuclear Information System (INIS)

    The toxicity of thorium by two green microalgae species, Monoraphidium sp. and Scenedesmus sp was studied. During the toxicity tests, the microalgae cultures were inoculated in ASM-I culture medium in the presence and absence of thorium (cultures at pH 8.0 and 6.0 in the absence of thorium, - control - and at pH 6.0 for thorium concentrations ranging from 0.5 to 100.0 mg/L Th). Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with the help of software developed by the group during the experiments. The difference in pH value in the culture medium did not affect the growth of the microalgae, and pH 6.0 was chosen as a reference in order not to compromise solubility and speciation of thorium in solution. The toxicity of the metal over the species was observed just for thorium concentrations over 50.0 mg/L. A Monoraphidium sp. culture containing 6.25x105 microorganisms/mL reached a final concentration of 5.52x107 microorganisms/mL in the presence of thorium in the concentration of 10.0 mg/L. If we consider the 100.0 ppm thorium solution reached a final concentration of 8.57x106 microorganisms/mL. Control tests indicated a final concentration of 2.51x107 microorganisms/mL at the end of the growth. Scenedesmus sp. cells proved to be more resistant to the presence of thorium in solution. Low concentrations of the radionuclide favored the growth of these microalgae. A culture containing 7.65x105 microorganisms/mL reached a final concentration of 2.25x106 microorganisms/mL, in the absence of thorium in the medium. Toxicological tests indicated a final culture concentration of 5.87x106 microorganisms/mL in the presence of 0.5 mg/L thorium. The software used for comparison of direct count method proved to be very useful for the improvement of accuracy of the results obtained and a decrease in the uncertainty in counting. Beyond these advantages it also allowed recording of the data. From the present results one can conclude, that the presence of

  17. Nuclear feasibility study on thorium fueled PWR core

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Hyun; Woo, Il Tak; Lim, Jae Yong; Ku, Bon Seung; Kim, Jong Chae; Lee, Sang Yun [Kyunghee University, Seoul (Korea)

    1999-04-01

    A computer code system, HELIOS and NESTLE or MASTER was established and checked for its reliability for the calculation of thorium fueled reactor. Previous results for the thorium fuel applications were evaluated including RTR reactor concept. Based on the detailed analysis on RTR, a new design concept was proposed. Characteristics of designed core should be checked for conversion ratio, nuclear design feasibility, proliferation resistance, fuel cycle economics, thermal-hydraulic safety, etc. Research was done only for the nuclear feasibility and high conversion in this 1st year. In order to seek for the design methodology, parametric studies were done for the following design parameters-fuel pin size, seed/blanket ratio, fuel material composition, and fissile enrichment. An optimization was done based on once-through fuel cycle with UO{sub 2} seed and (U, Th)O{sub 2} blanket. Economics, safety, non-proliferation, and waste transmutation will be checked in the future research works. (author). 19 refs., 39 figs., 39 tabs.

  18. Promises and Challenges of Thorium Implementation for Transuranic Transmutation - 13550

    Energy Technology Data Exchange (ETDEWEB)

    Franceschini, F.; Lahoda, E.; Wenner, M. [Westinghouse Electric Company LLC, Cranberry Township, PA (United States); Lindley, B. [University of Cambridge (United Kingdom); Fiorina, C. [Polytechnic of Milan (Italy); Phillips, C. [Energy Solutions, Richland, WA (United States)

    2013-07-01

    This paper focuses on the challenges of implementing a thorium fuel cycle for recycle and transmutation of long-lived actinide components from used nuclear fuel. A multi-stage reactor system is proposed; the first stage consists of current UO{sub 2} once-through LWRs supplying transuranic isotopes that are continuously recycled and burned in second stage reactors in either a uranium (U) or thorium (Th) carrier. The second stage reactors considered for the analysis are Reduced Moderation Pressurized Water Reactors (RMPWRs), reconfigured from current PWR core designs, and Fast Reactors (FRs) with a burner core design. While both RMPWRs and FRs can in principle be employed, each reactor and associated technology has pros and cons. FRs have unmatched flexibility and transmutation efficiency. RMPWRs have higher fuel manufacturing and reprocessing requirements, but may represent a cheaper solution and the opportunity for a shorter time to licensing and deployment. All options require substantial developments in manufacturing, due to the high radiation field, and reprocessing, due to the very high actinide recovery ratio to elicit the claimed radiotoxicity reduction. Th reduces the number of transmutation reactors, and is required to enable a viable RMPWR design, but presents additional challenges on manufacturing and reprocessing. The tradeoff between the various options does not make the choice obvious. Moreover, without an overarching supporting policy in place, the costly and challenging technologies required inherently discourage industrialization of any transmutation scheme, regardless of the adoption of U or Th. (authors)

  19. Conceptual design of a commercial accelerator driven thorium reactor

    International Nuclear Information System (INIS)

    This paper describes the substantial work done in underpinning and developing the concept design for a commercial 600 MWe, accelerator driven, thorium fuelled, lead cooled, power producing, fast reactor. The Accelerator Driven Thorium Reactor (ADTR TM) has been derived from original work by Carlo Rubbia. Over the period 2007 to 2009 Aker Solutions commissioned this concept design work and, in close collaboration with Rubbia, developed the physics, engineering and business model. Much has been published about the Energy Amplifier concept and accelerator driven systems. This paper concentrates on the unique physics developed during the concept study of the ADTR TM power station and the progress made in engineering and design of the system. Particular attention is paid to where the concept design has moved significantly beyond published material. Description of challenges presented for the engineering and safety of a commercial system and how they will be addressed is included. This covers the defining system parameters, accelerator sizing, core and fuel design issues and, perhaps most importantly, reactivity control. The paper concludes that the work undertaken supports the technical viability of the ADTR TM power station. Several unique features of the reactor mean that it can be deployed in countries with aspirations to gain benefit from nuclear power and, at 600 MWe, it fits a size gap for less mature grid systems. It can provide a useful complement to Generation III, III+ and IV systems through its ability to consume actinides whilst at the same time providing useful power. (authors)

  20. Decommissioning and rehabilitation of uranium and thorium production facilities

    International Nuclear Information System (INIS)

    The use of nuclear energy for military as well as for peaceful purposes was and remains closely connected with the mining and processing of uranium ore and, to a lesser extent, of thorium ore. Mining and processing of radioactive ores are characterised by the generation of huge amounts of radioactive residues, massive impacts upon ecosystems, landscape reshaping (or devastation in some places), and the monostructural socio-economic orientation of human settlement areas. However, a great number of the mines and mills commissioned during the cold war have been already closed, either for deposits being depleted of economically recoverable resources or on political grounds. The specifics of uranium/thorium mining and milling make high demands on the decommissioning and rehabilitation of the facilities which in addition to radiological aspects would have to address issues such as water pollution control and soil conservation, future site re-use, landscaping, and infrastructure development. The present paper gives an overview of the state of decommissioning and rehabilitation. Radiological specifics and their integration into the decommissioning and rehabilitation management are demonstrated for the rehabilitation of uranium mining legacies in Saxony and Thuringia. (orig.)

  1. Mortality among male workers at a thorium-processing plant

    International Nuclear Information System (INIS)

    Mortality is described in a cohort of 3039 men who were employed between 1940 and 1973 at a company involved in the production of thorium and rare earth chemicals from monazite sand. The standardized mortality ratio (SMR) for all causes was 1.05. SMR's were high for cancers of the lung (1,44), rectum (1.90), and pancreas (2.01), and for motor vehicle accidents (1.64). A subgroup of 592 men who worked for one year or longer in selected jobs (laborer, operator, maintenance) was followed up more intensively. SMR's were high for both lung cancer (1.62; 95% CL = 0.78 and 2.98) and pancreatic cancer (4.01; 95% CL = 1.30 and 9.34). The higher proportion of smokers in this subgroup relative to US males could have explained at least part of the excess mortality from lung cancer. Continued follow-up of the cohort in morbidity and mortality studies is needed to evaluate further these possible long-term effects of exposure to radioactivity and chemicals in the thorium extraction process

  2. Neutron activation analysis of airborne thorium liberated during welding operations

    Energy Technology Data Exchange (ETDEWEB)

    Glasgow, D.C.; Robinson, L.; Janjovic, J.T.

    1996-02-01

    Typically, reactive metals such as aluminum are welded using a thoriated tungsten welding electrode which is attached to a source of argon gas such that the local atmosphere around the weld is inert. The metal is heated by the arc formed between the electrode and the grounded component to be welded. During this process, some of the electrode is vaporized in the arc and is potentially liberated to the surrounding air. This situation may result in a hazardous airborne thorium level. Because the electrode is consumed during welding, the electrode tip must be repeatedly dressed by grinding the tip to a fine point so that the optimal welding conditions are maintained. These grinding activities may also release thorium to the air. Data generated in the 1950s suggested that these electrodes posed no significant health hazard and seemed to justify their exemption from licensing requirements for source material. Since that time, other studies have been performed and present conflicting results as to the level of risk. Values both above and below the health protection limit in use in the United States, have been reported in the literature recently. This study is being undertaken to provide additional data which may be useful in evaluating both the chemical toxicity risk and radiological dose assessment criteria associated with thoriated tungsten welding operations.

  3. Accelerator molten-salt breeding and thorium fuel cycle

    International Nuclear Information System (INIS)

    The recent efforts at the development of fission energy utilization have not been successful in establishing fully rational technology. A new philosophy should be established on the basis of the following three principles: (1) thorium utilization, (2) molten-salt fuel concept, and (3) separation of fissile-breeding and power-generating functions. Such philosophy is called 'Thorium Molten-Salt Nuclear Energy Synergetics [THORIMS-NES]'. The present report first addresses the establishment of 233U breeding fuel cycle, focusing on major features of the Breeding and Chemical Processing Centers and a small molten-salt power station (called FUJI-II). The development of fissile producing breeders is discussed in relation to accelerator molten-salt breeder (AMSB), impact fusion molten-salt breeder, and inertial-confined fusion hybrid molten-salt breeder. Features of the accelerator molten-salt breeder are described, focusing on technical problems with accelerator breeders (or spallators), design principle of the accelerator molten-salt breeder, selection of molten salt compositions, and nuclear- and reactor-chemical aspects of AMSB. Discussion is also made of further research and development efforts required in the future for AMSB. (N.K.)

  4. Electrodeposition of uranium and thorium onto small platinum electrodes

    Science.gov (United States)

    Reichenberger, Michael A.; Ito, Takashi; Ugorowski, Philip B.; Montag, Benjamin W.; Stevenson, Sarah R.; Nichols, Daniel M.; McGregor, Douglas S.

    2016-03-01

    Preparation of thin U- and Th-coated 0.3 mm diameter Pt working electrodes by the cyclic potential sweep method is described. Uranyl- and thorium hydroxide layers were electrodeposited from ethanol solutions containing 0.02 M natural uranyl and 0.02 M natural thorium nitrate, each with 3.6 M ammonium nitrate. The cell for electrodeposition was specially developed in order to accommodate the small working electrodes for this research by including a working electrode probe, 3-D translation stage, and microscope. The source material deposition was analyzed using digital microscopy and scanning electron microscopy, and confirmed using x-ray fluorescence measurements. The appropriate potential range for electrodeposition was determined to be -0.62 V to -0.64 V for a 0.3 mm diameter Pt working electrode placed 1 cm from the counter electrode. Smooth, uniform deposition was observed near the central region of the working electrode, while surface cracking and crystalline formations were found near the edge of the working electrode. The final procedure for sample substrate preparation, electrolytic solution preparation and electrodeposition are described.

  5. Thorium fuel cycle studies: fuel fabrication process and cost estimation

    International Nuclear Information System (INIS)

    Early in 1976 a study was made to assess the relative economics and fuel utilization of thorium and uranium fuel cycles in various types of reactors. It was to be completed in approximately two months, so all component parts had to be developed in a short time with a high degree of dependence on existing information. One of the components required for the study was a consistent set of relatively accurate fuel fabrication costs for the various reactor-fuel combinations. A report documents the rationale used in generating these cost estimates and presents in some detail the basis and methodology employed. Since three types of thermal flux reactors (LWR, HWR, and HTGR) and two types of fast flux reactors (liquid metal and gas cooled) together with three fuel forms (oxides, carbides, and metal) were included in the study with various combinations of the fissionable metals U, Th, and Pu, it was necessary to define a methodology that would permit a rapid relative estimate for each case. Existing cost studies were chosen for a Light-Water Reactor with low-enriched uranium fuel and for a High-Temperature Gas-Cooled Reactor with highly enriched uranium and thorium fuel as the reference cases which could be compared with other reactor-fuel combinations

  6. A study of pulse columns for thorium fuel reprocessing

    International Nuclear Information System (INIS)

    Two 5 m pulse columns with the same cartridge geometries are installed to investigate the performance. The characteristic differences of the aqueous continous and the organic continuous columns were investigated experimentally. A ternary system of 30% TBP in dodecane-acetic acid-water was adopted for the mass-transfer study. It was concluded that the overall mass-transfer coefficient was independent of whether the mass-transfer is from the dispersed to the continuous phase or from the continuous to the dispersed phase. Thorium nitrate was extracted and reextracted using both modes of operation. Both HETS and HTU were obtained. The aqueous continuous column gave much shorter HTU than the organic continuous column. In reextraction the organic continuous column gave shorter HTU. The Thorex-processes for uranium and thorium co-extraction, co-stripping, and partitioning were studied. Both acid feed solution and acid deficiend feed solution were investigated. The concentration profiles along the column height were obtained. The data were analysed with McCABE-THIELE diagrams to evaluate HETS. (orig./HP)

  7. Determination of thorium and uranium particles in monazite airborne

    International Nuclear Information System (INIS)

    The work is the determination of the Mass Median Aerodynamic Diameter of Airborne particles of Th and U, produced during the milling of monazite in Monozite Sand Plants. The air samples was collected using a Cascade Impactor from Delron DCI-6 with a flux of 12,5 1/min and cut-off diametes of 0,5, 1,0, 4,0, 8,0 and 16,0 μm. Each stage of the cascate impactor was analysed by measuring the X rays induced in collision with 2 MeV protons acellereted by a 4 MV Van de Graaff acceletor located at University Catolic, PUC, RJ. The MMAD found for Th and U was of 1,15 μm with a geometric standard desviation of 2,0. Take in acount that there are more thorium than uranium in the brazilian monazite, and the 232Th 238U are thr principal isotopes at the Th and U natural radioative decay series, we considered the mass and the activity distribution as equal. The mean concentration of Th (17,0 Bq/m3) record in the air was 42% above 3/10 of international limit for concentration of oxides of thorium in the air, while the concentration of U remaind below 1/10 of the limit for concentration of U3O8 in the air. (author)

  8. Core design for thorium-uranium breeding recycle in PWRs

    International Nuclear Information System (INIS)

    Two kinds of mixed core designs were investigated in this study respectively with partially PuThOX (plutonium-thorium mixed oxide) and U3ThOX (reactor grade 233U-thorium mixed oxide) loading on the basis of reference full UOX (uranium-oxide) equilibrium-cycle core design. In UOX/U3ThOX mixed core/ U3ThOX fuel assemblies stay in-core for 6 cycles of which average cycle length is 5 EFPD longer than that of reference full UOX core. Compared with initial load, the fissile material inventory in U3ThOX fuel increased by 7% via 1 year cooling after discharge. Furthermore, the fuel management scheme of UOX/MOX (plutonium-uranium mixed oxide) mixed core was designed for comparison. The results show that: 1) Mixed core with PuThOX loading has similar impacts as MOX on several neutronic characteristics, such as reduced differential boron worth, reduced control rod worth, higher critical boron concentration, more negative moderator temperature coefficient, reduced shutdown margin and larger Doppler power defects; 2) mixed core with U3ThOX loading has no distinct impacts on neutronic characteristics compared with reference full UOX core. (authors)

  9. Current extraction and separation of uranium, thorium and rare earths elements from monazite leach solution using organophosphorous extractants

    International Nuclear Information System (INIS)

    A new process based on solvent extraction has been developed for separation of uranium, thorium and rare earths from monazite leach solution using organophosphorous extractants. The Thorium cake coming from monazite source was dissolved in HNO3 medium in presence of trace amount of HF for feed preparation. The separation of U(VI) was carried out by liquid-liquid extraction using tris-2-ethyl hexyl phosphoric acid (TEHP) in dodecane leaving thorium and rare earths elements in the raffinate. The thorium from raffinate was selectively extracted using 1M tri iso amyl phosphate (TiAP) in dodecane in organic phase leaving all rare earths elements in aqueous solution. The uranium and thorium from organic medium was quantitatively stripped using 0.05 M HNO3 counter current mode. Results indicate the quantitative separation of uranium, thorium and rare earths from thorium cake (monazite source) using organophosphorous extractant in counter current mode

  10. Biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2 isolated from soil

    Institute of Scientific and Technical Information of China (English)

    兰图; 刘宁; 张东; 杨吉军; 罗顺忠; 安竹; 邬琦琦; 杨远友; 冯更生; 唐军

    2015-01-01

    To develop a microbe-based bioremediation strategy for cleaning up thorium-contaminated sites, we have investigated the biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2, one of the dominant species of bacterial groups isolated from soils in Southwest China. Thorium biosorption depended on the pH of environment, and its rapid biosorption reached a maximum of up to 10.75 mg Th per gram of the bacteria (wet wt.) at pH 3.0. The biosorption agreed bettter with Langmuir isotherm model than Freundlich model, indicating that thorium biosorption was a monolayer adsorption. The thermodynamic parameters, negative change in Gibbs free energy and positive value in enthalpy and entropy, suggested that the biosorption was spontaneous, more favorable at higher temperature and endothermic process with an increase of entropy. Scanning electron microscopy (SEM) indicated that thorium initially binded with the cell surface, while transmission electron microscopy (TEM) revealed that Th deposited in the cytoplasm and served as cores for growth of element precipitation (e.g., phosphate minerals) or by self-precipitation of hydroxides, which is probably controlled by ion-exchange, as evidenced by particle induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). Fourier Transform Infrared (FTIR) further indicated that thorium biosorption involved carboxyl and phosphate groups and protein in complexation or electrostatic interaction. Overall results indicated that a combined electrostatic interaction-complexation-ion exchange mechanism could be involved in thorium biosorption by Bacillus sp. dwc-2.

  11. The Tarascan Indian House.

    Science.gov (United States)

    Quinn, Joyce

    1989-01-01

    This lesson plan introduces K-grade three students to Mexican Indian architecture. Students will become familiar with the cultural context of the Indian treasure house; discuss the use of wood as the sole building material; compare the treasure house with present day structures; and create miniature treasure houses using wood materials. (GEA)

  12. Pima Indian Legends.

    Science.gov (United States)

    Shaw, Anna Moore

    The stated purpose of this book is to preserve in writing some of the Pima Indian legends that had been verbally passed from generation to generation in the past. This collection of 23 legends, which were originally used to instruct the young people of the tribe, presents in story form various aspects of American Indian life--including…

  13. Indians of California.

    Science.gov (United States)

    Bureau of Indian Affairs (Dept. of Interior), Washington, DC.

    A brief historical review of the American Indian in California from prehistoric to modern times indicates the hardships and economic disadvantages which the Indians have suffered in the acculturation process. Discussion of the treaties which were negotiated and the Federal legislation which was passed indicates an attempt on the part of modern day…

  14. Indian Ocean Rim Cooperation

    DEFF Research Database (Denmark)

    Wippel, Steffen

    Since the mid-1990s, the Indian Ocean has been experiencing increasing economic cooperation among its rim states. Middle Eastern countries, too, participate in the work of the Indian Ocean Rim Association, which received new impetus in the course of the current decade. Notably Oman is a very active...

  15. Indian Inuit Pottery '73

    Science.gov (United States)

    Tawow, 1974

    1974-01-01

    A unique exhibit of Canadian Native Ceramics which began touring various art galleries in September 1973 is described both verbally and photographically. The Indian Inuit Pottery '73 display, part of the 1973 International Ceramics Exhibition, includes 110 samples of craftsmanship from Indian and Inuit artists across Canada. (KM)

  16. Dietary intake of naturally occurring radionuclides from thorium series, uranium series and potassium-40 in high background radiation areas of Manavalakurichi, Tamil Nadu

    International Nuclear Information System (INIS)

    Natural background radiation is a major source of human exposure to radiation. The source of background radiation is due to monazite containing naturally occurring radionuclides like thorium and uranium. These natural radionuclides are found in all environmental matrices like rocks, soil, water, and dietary sources. The intake of natural radionuclides to public would occur in ingestion pathway via dietary sources. The present study aims to evaluate the natural radionuclides in dietary sources from Manavalakurichi region, which is a High Background Radiation Area's (HBRA's) in Tamil Nadu. The natural radionuclides such as Uranium (238U and 234U), Radium (226Ra and 228Ra), Polonium (210Po) and Potassium (40K) in the dietary products were analyzed in various dietary sources and computed the ingestion dose for different age group of public residing in and around Manavalakurichi. The study can act as existing data for Indian population living in the high radiation background areas

  17. Thorium cycle and molten salt reactors: field parameters and field constraints investigations toward 'thorium molten salt reactor' definition

    International Nuclear Information System (INIS)

    Producing nuclear energy in order to reduce the anthropic CO2 emission requires major technological advances. Nuclear plants of 4. generation have to respond to several constraints, as safety improvements, fuel breeding and radioactive waste minimization. For this purpose, it seems promising to use Thorium Cycle in Molten Salt Reactors. Studies on this domain have already been carried out. However, the final concept suffered from serious issues and was discontinued. A new reflection on this topic is being led in order to find acceptable solutions, and to design the Thorium Molten Salt Reactor concept. A nuclear reactor is simulated by the coupling of a neutron transport code with a materials evolution code. This allows us to reproduce the reactor behavior and its evolution all along its operation. Thanks to this method, we have studied a large number of reactor configurations. We have evaluated their efficiency through a group of constraints they have to satisfy. This work leads us to a better understanding of many physical phenomena controlling the reactor behavior. As a consequence, several efficient configurations have been discovered, allowing the emergence of new points of view in the research of Molten Salt Reactors. (author)

  18. Thorium compounds processing at IPEN-CNEN/SP - Brazil and recent research initiatives

    International Nuclear Information System (INIS)

    Brazil has a long tradition in the thorium technology, from mining of monazite until the obtainment of high purity thorium compounds and IPEN has accumulated since the 60's a wide experience in the purification of thorium, obtained primarily from the monazite processing. Brazil has one of the biggest world nuclear resources (uranium and thorium), being the sixth natural uranium resource in the world (309,000 t U3O8), one of the first world thorium natural resource. The reasonably assured reserves and the estimated additional resources can reach 1.3 million metric tons of ThO2. Unfortunately, Brazil has not a thorium program and there never was a national program, lasting for a period sufficient to produce practical results of effective use of thorium in the Brazilian reactors. Worse, the specific research activities on different topics of the thorium cycle have declined over time, due to the lack of interest and support. An autonomous nuclear program was carried out in the country in the 80's. However, major political changes occurred in the program in the early 90's. These changes contributed to the further reduction of interest in alternative nuclear fuel cycles. Unfortunately, contrarily to what is happening in some countries in recent years, nowadays Brazil is paying little attention to the thorium, even less than in the past, despite its huge reserves. There are only limited and localized initiatives from some researchers. Some proposals would be an excellent opportunity to keep the existent capabilities in the institution that will be strategically important for the country in the future

  19. Band structure and decay channels of thorium-229 low-lying isomeric state for ensemble of thorium atoms adsorbed on calcium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Borisyuk, Petr V.; Vasilyev, Oleg S.; Krasavin, Andrey V.; Troyan, Victor I. [National Research Nuclear University ' ' MEPhI' ' (Moscow Engineering Physics Institute), Kashirskoye shosse 31, 115409 Moscow (Russian Federation); Lebedinskii, Yury Yu. [National Research Nuclear University ' ' MEPhI' ' (Moscow Engineering Physics Institute), Kashirskoye shosse 31, 115409 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Moscow region (Russian Federation); Tkalya, Eugene V. [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie gory, 119991 Moscow (Russian Federation); Nuclear Safety Institute of Russian Academy of Science, Bol' shaya Tulskaya 52, 115191 Moscow (Russian Federation)

    2015-12-15

    The results are presented on the study of the electronic structure of thorium atoms adsorbed by the liquid atomic layer deposition from aqueous solution of thorium nitrate on the surface of CaF{sub 2}. The chemical state of the atoms and the change of the band structure in the surface layers of Th/CaF{sub 2} system on CaF{sub 2} substrate were investigated by XPS and REELS techniques. It was found that REELS spectra for Th/CaF{sub 2} system include peaks in the region of low energy losses (3-7 eV) which are missing in the similar spectra for pure CaF{sub 2}. It is concluded that the presence of the observed features in the REELS spectra is associated with the chemical state of thorium atoms and is caused by the presence of uncompensated chemical bonds at the Th/CaF{sub 2} interface, and, therefore, by the presence of unbound 6d- and 7s-electrons of thorium atoms. Assuming the equivalence of the electronic configuration of thorium-229 and thorium-232 atoms, an estimate was made on the time decay of the excited state of thorium-229 nuclei through the channel of the electron conversion. It was found that the relaxation time is about 40 μs for 6d-electrons, and about 1 μs for 7s-electrons. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Role of Thorium to Supplement Fuel Cycles of Future Nuclear Energy Systems

    International Nuclear Information System (INIS)

    The investigation of the thorium fuel cycle (ThFC) is a collaborative INPRO (International Project on Innovative Nuclear Reactors and Fuel Cycles) activity within its main area on global vision on sustainable nuclear energy for the 21st century. The current publication reports on the sustainability of nuclear power by re-examining the potential of thorium-based fuel cycles to support future large scale deployment of nuclear energy systems by increasing the availability of nuclear material. Special attention is paid to the thorium fuel cycle from the point of view of economics and proliferation resistance.

  1. Analytical methods for thorium determination: A journey from conventional methods to novel applications

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, K.; Ottmar, H.; Tamborini, G.; Ray, I.; Thiele, H

    2001-07-01

    Thorium may be determined using a variety of analytical methods. These may be based on chemical or physical principles or may make use of the radioactive decay of the individual thorium isotopes. The method to be used for a certain analytical purpose is selected as a function of the matrix of the sample and of the concentration of thorium. The present paper describes different methodologies, their range of application and discusses selected results. The methods described cover a concentration range of more than twelve orders of magnitude, i.e. from concentrated solutions to micrometre-sized particles. Emphasis is given to active radiometric techniques, chemical and instrumental analysis. (author)

  2. A sequential separation procedure for the determination of Uranium, Thorium and their isotopes in geological materials

    International Nuclear Information System (INIS)

    Inductively coupled plasma atomic emission spectrometry(ICP/AES) was used for the determination of uranium and thorium in geological materials. Samples were predecomposed by mixed acid digestion technique. The separation of the uranium and thorium was achieved by systematic solvent extraction with TTA(thenoyltrifluoroacetone) and TOA(tri-n-octylamine) and back extraction into HCl. The results for standard rock sample, NIST SRM 278, showed a good agreement with those certified from NIST as well as found values by other non-destructive techniques. Additional purification for extracted portions was carried out by anion exchange chromatography for measurement of several natural radioisotopes of uranium and thorium by alpha spectrometry. (author)

  3. Thorium determination in intercomparison samples and in some Romanian building materials by gamma ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pantelica, A.; Georgesecu, I.I.; Murariu-Magureanu, M.D.; Margaritescu, I.; Cincu, E

    2001-07-01

    Thorium content in zircon sand, thorium ore and thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement, cement mill dust, coal fly ash, bricks, and tile (28 samples) were determined by gamma ray spectrometry. For the building materials, {sup 226}Ra, {sup 40}K and {sup 137}Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for {sup 232}Th, {sup 226}Ra, and {sup 40}K radioactivity, and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples. (author)

  4. Thorium determination in intercomparison samples and in some Romanian building materials by gamma ray spectrometry

    International Nuclear Information System (INIS)

    Thorium content in zircon sand, thorium ore and thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement, cement mill dust, coal fly ash, bricks, and tile (28 samples) were determined by gamma ray spectrometry. For the building materials, 226Ra, 40K and 137Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for 232Th, 226Ra, and 40K radioactivity, and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples. (author)

  5. Determination of thorium in environmental and workplace materials by ICP-MS

    International Nuclear Information System (INIS)

    The paper outlines the advantages of the use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) over radiometric techniques to measure natural thorium, 232Th. Experimental parameters that must be taken into account in the sample digestion, preparation and ICP-MS analysis of environmental (soils, rocks, sediments) or workplace (thorium oxide, reference solutions) materials are described. The methods presented are applied to various reference materials, with the aim of providing suitable procedures to be useful for other important thorium containing materials (such as monazite sands or welding electrodes). The participation in a European Commission intercomparison exercise is detailed and a comparison with alpha spectrometry is made

  6. Measurement of the thorium-228 activity in solutions cavitated by ultrasonic sound

    CERN Document Server

    Ford, R; Vazquez-Jauregui, E

    2009-01-01

    We show that cavitation of a solution of thorium-228 in water does not induce its transformation at a faster rate than the natural radioactive decay. We measured the activity of a thorium-228 solution in water before, and after, it was subjected to a cavitation at 44 kHz and $250 $W for 90 minutes in order to observe any change in the thorium half-life. The results were compared to the original activity of the sample and we observed no change. Our results and conclusions conflict with those in a recent paper by F. Cardone et. al. [Phys. Lett. A 373 (2009) 1956-1958].

  7. Thorium Deposits of the United States - Energy Resources for the Future?

    Science.gov (United States)

    Van Gosen, Bradley S.; Gillerman, Virginia S.; Armbrustmacher, Theodore J.

    2009-01-01

    Many nations are exploring new ways to meet their growing energy supply needs, with a particular focus upon methods that produce lower carbon dioxide emissions compared to traditional oil, natural gas, and coal power plants. As a result, thorium-based nuclear power has experienced renewed attention as a potential energy source. Thus, it benefits the United States and other countries to identify and evaluate their indigenous thorium resources. This report describes the geology and resources of the principal thorium districts of the United States.

  8. The foam separation of thorium(IV) from dilute aqueous solutions

    International Nuclear Information System (INIS)

    The foam separation of thorium(IV) from the dilute aqueous solutions was investigated at pH values ranging from 1.2 to 12 using the cationic surfactant cetyl trimethyl ammonium bromide and the anionic collector sodium lauryl sulphate. Cetyl trimethyl ammonium bromide could not remove soluble thorium but partially floated the hydrous oxide. The percentage removal was found to depend on the pH. With sodium lauryl sulphate, removals approaching 100% could be achieved at all the pH values tested. The various factors that can affect the separation process investigated and the results are discussed in terms of the hydrolysis of thorium. (orig.)

  9. Thorium and uranium in soil fractions and certain macromycete species in boreal forest ecosystems

    OpenAIRE

    M. M. Vinichuk

    2012-01-01

    The content of thorium (Th) and uranium (U) in fractions of soil edaphosphere, rhizosphere, rhizoplane, fungal mycelium and fruit bodies were investigated. The concentrations of thorium in edaphosphere and rhizosphere fractions and mycelia of fungi are not different significantly and vary in the range of 0.74–1.45 mg kg–1 dry matter. The concentration of thorium in the rhizoplane fraction is 4 times lower than in the bulk soil – edaphosphere. The concentrations of uranium in edaphosphere, rhi...

  10. Study of the thorium incorporation by inhalation in individuals occupationally exposed

    International Nuclear Information System (INIS)

    A mathematical model describing the metabolism of inhaled thorium in the human body was developed. Through this model theoretical limits of excretion were calculated for workers of a monazite plant (Usina Santo Amaro). This limits were based on International Commission on Radiological Protection publication 30, 1979. Excreta samples from twelve workers of Usina Santo Amaro were collected and analysed for thorium. All samples were bellow the theoretical limits of excretion indicating that Usina Santo Amaro workers are exposed to thorium levels bellow the Annual Limits of Intake recommended by ICRP, publication 30. (author)

  11. Determination of thorium and uranium contents in soil samples using SSNTD's passive method

    Indian Academy of Sciences (India)

    T A Salama; U Seddik; T M Dsoky; A Ahmed Morsy; R El-Asser

    2006-08-01

    Thorium-to-uranium ratios have been determined in different soil samples using CR-39 and LR-115-II solid-state nuclear track detectors (SSNTDs). A calibration method based on determination of SSNTD registration sensitivity ratio for -particles of thorium and uranium series has been developed. Thorium and uranium contents of the standard soil samples have been determined and compared with its known values. There is a good agreement between the results of this method and the values of standard samples. The method is simple, inexpensive, non-destructive and has a wide range of applications in environment, building materials and petroleum fields.

  12. The Crystal Structure of Thorium and Zirconium Dihydrides by X-ray and Neutron Diffraction

    Science.gov (United States)

    Rundle, R.E.; Shull, C.G.; Wollan, E.O.

    1951-04-20

    Thorium forms a tetragonal lower hydride of composition ThH{sub 2}. The hydrides ThH{sub 2}, ThD{sub 2}, and ZrD{sub 2} have been studied by neutron diffraction in order that hydrogen positions could be determined. The hydrides are isomorphous, and have a deformed fluorite structure. Metal-hydrogen distances in thorium hydride are unusually large, as in UH{sub 3}. Thorium and zirconium scattering amplitudes and a revised scattering amplitude for deuterium are reported.

  13. Uranium and thorium determination in water samples taken along River Kura

    International Nuclear Information System (INIS)

    Full text : In the present investigation, uranium and thorium concentration in rivers water of Azerbaijan has been measured using inductively coupled plasma mass spectrometry. The Agilent 7700x series ICP-MS applied for analysis of water samples. This method is based on direct introduction of samples, without any chemical pre-treatment, into an inductively coupled plasma plasma mass spectrometer. Uranium and thorium was determined at the mass mass numbers of 238 and 232 respectively using Bi-209 as internal standard. The main purpose of the study is to measure the level of uranium and thorium in water samples taken along river Kura

  14. High-quality thorium TRISO fuel performance in HTGRs

    International Nuclear Information System (INIS)

    Thorium as a nuclear fuel has received renewed interest, because of its widespread availability and the good irradiation performance of Th and mixed (Th,U) oxide compounds as fuels in nuclear power systems. Early HTGR development employed thorium together with high-enriched uranium (HEU). After 1980, HTGR fuel systems switched to low-enriched uranium (LEU). After completing fuel development for the AVR and the THTR with BISO coated particles, the German program expanded its efforts utilizing thorium and HEU TRISO coated particles in advanced HTGR concepts for process heat applications (PNP) and direct-cycle electricity production (HHT). The combination of a low-temperature isotropic (LTI) inner and outer pyrocarbon layers surrounding a strong, stable SiC layer greatly improved manufacturing conditions and the subsequent contamination and defective particle fractions in production fuel elements. In addition, this combination provided improved mechanical strength and a higher degree of solid fission product retention, not known previously with high-temperature isotropic (HTI) BISO coatings. The improved performance of the HEU (Th, U)O2 TRISO fuel system was successfully demonstrated in three primary areas of development: manufacturing, irradiation testing under normal operating conditions, and accident simulation testing. In terms of demonstrating performance for advanced HTGR applications, the experimental failure statistic from manufacture and irradiation testing are significantly below the coated particle requirements specified for PNP and HHT designs at the time. Covering a range to 1300 C in normal operations and 1600 C in accidents, with burnups to 13% FIMA and fast fluences to 8 x 1025 n/m2 (E> 16 fJ), the performance results exceed the design limits on manufacturing and operational requirements for the German HTR-Modul concept, which are 6.5 x 10-5 for manufacturing, 2 x 10-4 for normal operating conditions, and 5 x 10-4 for accident conditions. These

  15. High-quality thorium TRISO fuel performance in HTGRs

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Forschungszentrum Juelich GmbH (Germany); Allelein, Hans-Josef [Forschungszentrum Juelich GmbH (Germany); Technische Hochschule Aachen (Germany); Nabielek, Heinz; Kania, Michael J.

    2013-11-01

    Thorium as a nuclear fuel has received renewed interest, because of its widespread availability and the good irradiation performance of Th and mixed (Th,U) oxide compounds as fuels in nuclear power systems. Early HTGR development employed thorium together with high-enriched uranium (HEU). After 1980, HTGR fuel systems switched to low-enriched uranium (LEU). After completing fuel development for the AVR and the THTR with BISO coated particles, the German program expanded its efforts utilizing thorium and HEU TRISO coated particles in advanced HTGR concepts for process heat applications (PNP) and direct-cycle electricity production (HHT). The combination of a low-temperature isotropic (LTI) inner and outer pyrocarbon layers surrounding a strong, stable SiC layer greatly improved manufacturing conditions and the subsequent contamination and defective particle fractions in production fuel elements. In addition, this combination provided improved mechanical strength and a higher degree of solid fission product retention, not known previously with high-temperature isotropic (HTI) BISO coatings. The improved performance of the HEU (Th, U)O{sub 2} TRISO fuel system was successfully demonstrated in three primary areas of development: manufacturing, irradiation testing under normal operating conditions, and accident simulation testing. In terms of demonstrating performance for advanced HTGR applications, the experimental failure statistic from manufacture and irradiation testing are significantly below the coated particle requirements specified for PNP and HHT designs at the time. Covering a range to 1300 C in normal operations and 1600 C in accidents, with burnups to 13% FIMA and fast fluences to 8 x 10{sup 25} n/m{sup 2} (E> 16 fJ), the performance results exceed the design limits on manufacturing and operational requirements for the German HTR-Modul concept, which are 6.5 x 10{sup -5} for manufacturing, 2 x 10{sup -4} for normal operating conditions, and 5 x 10{sup -4

  16. Recovery of thorium and rare earths by their peroxides precipitation from a residue produced in the thorium purification facility; Recuperacao de torio e terras raras via peroxido do residuo originado na unidade de purificacao de torio

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Antonio Alves de

    2008-07-01

    As consequence of the operation of a Thorium purification facility, for pure Thorium Nitrate production, the IPEN (Instituto de Pesquisas Energeticas e Nucleares) has stored away a solid residue called RETOTER (REsiduo de TOrio e TErras Raras). The RETOTER is rich in Rare-Earth Elements and significant amount of Thorium-232 and minor amount of Uranium. Furthermore it contains several radionuclides from the natural decay series. Significant radioactivity contribution is generated by the Thorium descendent, mainly the Radium-228(T{sub 1/2}=5.7y), known as meso thorium and Thorium-228(T{sub 1/2} 1.90y). An important thorium daughter is the Lead-208, a stable isotope present with an expressive quantity. After the enclosure of the operation of the Thorium purification facility, many researches have been developed for the establishment of methodologies for recovery of Thorium, Rare-Earth Elements and Lead-208 from the RETOTER. This work presents a method for RETOTER decontamination, separating and bordering upon some radioactive isotopes. The residue was digested with nitric acid and the Radium-228 was separated by the Barium Sulphate co-precipitation procedure. Finally, the Thorium was separated by the peroxide precipitation and the Rare-Earth Elements were also recovered by the Rare-Earth peroxide precipitation in the filtrate solution.(author)

  17. 77 FR 41200 - Indian Gaming

    Science.gov (United States)

    2012-07-12

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... of an extension to the Class III Gaming Compact between the State of California and the Federated... L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant Secretary--Policy...

  18. 77 FR 76514 - Indian Gaming

    Science.gov (United States)

    2012-12-28

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... publishes the Deemed Approved Amendment to the Tribal-State Compact between the State of California and the... CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant...

  19. 78 FR 44146 - Indian Gaming

    Science.gov (United States)

    2013-07-23

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... State of California taking effect. DATES: Effective Date: July 23, 2013. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant Secretary--Policy...

  20. 78 FR 54908 - Indian Gaming

    Science.gov (United States)

    2013-09-06

    ... activities on Indian lands. The Compact between the State of California and the Wiyot Tribe provides for... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... III Tribal- State Gaming Compact between the Wiyot Tribe and the State of California. DATES:...

  1. Indian Teachers and School Improvement.

    Science.gov (United States)

    Chavers, Dean

    2000-01-01

    Past failures in American Indian education are linked to lingering assimilationist practices, outdated curricula, and low expectations of Indian youth. A key to improving Indian education is changing school culture and increasing the numbers of Indian teachers and administrators. Elements of a model teacher education program are presented, and…

  2. New Indian Tribalism. Working Paper.

    Science.gov (United States)

    Beckmann, Kathleen

    The purposes of this paper are to identify the problems Washington State Indians face and to provide considerations that might assist in promoting the welfare and well-being of American Indians. It is stated that the major barrier to the Indian's success in American society is the attitude of the Anglo towards the Indian. Thus, the programs and…

  3. 76 FR 33341 - Indian Gaming

    Science.gov (United States)

    2011-06-08

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming... FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the...

  4. 78 FR 10203 - Indian Gaming

    Science.gov (United States)

    2013-02-13

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal State Class III Gaming Compact. SUMMARY: This notice publishes the Approval of the Class III Tribal- State Gaming Compact between the Chippewa-Cree Tribe of the Rocky Boy's Indian...

  5. 77 FR 59641 - Indian Gaming

    Science.gov (United States)

    2012-09-28

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming.... FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of...

  6. 76 FR 65208 - Indian Gaming

    Science.gov (United States)

    2011-10-20

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an Approval of the Gaming..., Office of Indian Gaming, Office of the Deputy Assistant Secretary--Policy and Economic...

  7. 77 FR 45371 - Indian Gaming

    Science.gov (United States)

    2012-07-31

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming... FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the...

  8. 75 FR 8108 - Indian Gaming

    Science.gov (United States)

    2010-02-23

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes approval of the Tribal-State Compact between the Pyramid Lake Paiute Indian Tribe and the State of Nevada Governing Class III...

  9. 75 FR 68618 - Indian Gaming

    Science.gov (United States)

    2010-11-08

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... the Red Cliff Band of Lake Superior Chippewas (``Tribe'') and the State of Wisconsin Gaming Compact of... CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant...

  10. 76 FR 56466 - Indian Gaming

    Science.gov (United States)

    2011-09-13

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an approval of the gaming...: September 13, 2011. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian...

  11. 76 FR 52968 - Indian Gaming

    Science.gov (United States)

    2011-08-24

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming... FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the...

  12. 77 FR 43110 - Indian Gaming

    Science.gov (United States)

    2012-07-23

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming... FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the...

  13. 78 FR 15738 - Indian Gaming

    Science.gov (United States)

    2013-03-12

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes an extension of the gaming..., 2013. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of...

  14. 75 FR 55823 - Indian Gaming

    Science.gov (United States)

    2010-09-14

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes an extension of Gaming.... FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of...

  15. 78 FR 26801 - Indian Gaming

    Science.gov (United States)

    2013-05-08

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes the approval of an amendment to the Class III Tribal-State Gaming Compact between the Menominee Indian Tribe of Wisconsin and...

  16. 78 FR 11221 - Indian Gaming

    Science.gov (United States)

    2013-02-15

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes an extension of the gaming..., 2013. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of...

  17. 75 FR 38833 - Indian Gaming

    Science.gov (United States)

    2010-07-06

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes the Approved Compact between... FURTHER INFORMATION CONTACT: Paula Hart, Director, Office of Indian Gaming, Office of the Deputy...

  18. 77 FR 76513 - Indian Gaming

    Science.gov (United States)

    2012-12-28

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Amended Tribal-State Class III Gaming Compact taking effect. SUMMARY: This notice publishes the... CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of the Deputy Assistant...

  19. 76 FR 8375 - Indian Gaming

    Science.gov (United States)

    2011-02-14

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes an extension of the Gaming..., 2011. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of Indian Gaming, Office of...

  20. 75 FR 68823 - Indian Gaming

    Science.gov (United States)

    2010-11-09

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Amendment. SUMMARY: This notice publishes approval of the Amendments to the Class III Gaming Compact (Amendment) between the State of Oregon and the Siletz Indians...

  1. Mortality among female workers at a thorium-processing plant

    International Nuclear Information System (INIS)

    The mortality patterns among a cohort of 677 female workers at a thorium-processing plant are reported for the period from 1940 to 1982. Of the 677 women, 165 were reported dead; 459 were still alive; and 53 (7.8%) were lost to follow-up. The standardized mortality ratios from all causes (0.74), all cancers (0.53), and circulatory diseases (0.66) were significantly below those for the general US population. In this cohort, 5 deaths due to lung cancer and 1 death from leukemia were observed, with 4.53 and 1.69 deaths expected, respectively. No deaths from cancer of the liver, pancreas, or bone were observed. Poisson regression analysis was used for an internal comparison within the cohort. The results of the Poisson regression analysis showed no significant effect on mortality rates of all causes and cancers from the study factors, including job classification, duration of employment, and time since first employment

  2. Catalogue of data on Thorium intake, organ burden and excretion

    International Nuclear Information System (INIS)

    The Atomic Energy Control Board is initiating the critical evaluation of current biokinetic and dosimetric models applicable to estimating exposure to the common chemical and physical forms of thorium. The identification and location of the relevant sets of data are the first steps of this project. This report describes the collection methods used and presents catalogues of the data on human and animal studies that have resulted from exposures under controlled experimental conditions, chronic occupational or environmental situations and acute accidental conditions. The data was identified through the use of computerized literature searches of the Cancerlit, Chemical Exposure, Embase, BIOSIS, NTIS, INIS, MEDLINE and Occupational Safety and Health (NIOSH) data bases, library research and telephone contact with currently active researchers in the field. A table is presented which categorizes researchers in the field accordingly to affiliation and country

  3. Feasibility study on the thorium fueled boiling water breeder reactor

    International Nuclear Information System (INIS)

    The feasibility of (Th,U)O 2 fueled, boiling water breeder reactor based on conventional BWR technology has been studied. In order to determine the potential use of water cooled thorium reactor as a competitive breeder, this study evaluated criticality, breeding and void reactivity coefficient in response to changes made in MFR and fissile enrichments. The result of the study shows that while using light water as moderator, low moderator to fuel volume ratio (MFR=0.5), it was possible to breed fissile fuel in negative void reactivity condition. However the burnup value was lower than the value of the current LWR. On the other hand, heavy water cooled reactor shows relatively wider feasible breeding region, which lead into possibility of designing a core having better neutronic and economic performance than light water with negative void reactivity coefficient. (authors)

  4. Burnup calculations using serpent code in accelerator driven thorium reactors

    International Nuclear Information System (INIS)

    In this study, burnup calculations have been performed for a sodium cooled Accelerator Driven Thorium Reactor (ADTR) using the Serpent 1.1.16 Monte Carlo code. The ADTR has been designed for burning minor actinides, mixed 232Th and mixed 233U fuels. A solid Pb-Bi spallation target in the center of the core is used and sodium as coolant. The system is designed for a heating power of 2 000 MW and for an operation time of 600 days. For burnup calculations the Advanced Matrix Exponential Method CRAM (Chebyshev Rational Approximation Method) and different nuclear data libraries (ENDF7, JEF2.2, JEFF3.1.1) were used. The effective multiplication factor change from 0.93 to 0.97 for different nuclear data libraries during the reactor operation period. (orig.)

  5. Burnup calculations using serpent code in accelerator driven thorium reactors

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, M.E.; Agar, O. [Karamanoglu Mehmetbey Univ., Karaman (Turkey). Physics Dept.; Yigit, M. [Aksaray Univ. (Turkey). Physics Dept.

    2013-07-15

    In this study, burnup calculations have been performed for a sodium cooled Accelerator Driven Thorium Reactor (ADTR) using the Serpent 1.1.16 Monte Carlo code. The ADTR has been designed for burning minor actinides, mixed {sup 232}Th and mixed {sup 233}U fuels. A solid Pb-Bi spallation target in the center of the core is used and sodium as coolant. The system is designed for a heating power of 2 000 MW and for an operation time of 600 days. For burnup calculations the Advanced Matrix Exponential Method CRAM (Chebyshev Rational Approximation Method) and different nuclear data libraries (ENDF7, JEF2.2, JEFF3.1.1) were used. The effective multiplication factor change from 0.93 to 0.97 for different nuclear data libraries during the reactor operation period. (orig.)

  6. Nuclear thermionic converter. [tungsten-thorium oxide rods

    Science.gov (United States)

    Phillips, W. M.; Mondt, J. F. (Inventor)

    1977-01-01

    Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability.

  7. Ab-initio calculations on melting of thorium

    Science.gov (United States)

    Mukherjee, D.; Sahoo, B. D.; Joshi, K. D.; Kaushik, T. C.; Gupta, Satish C.

    2016-05-01

    Ab-initio molecular dynamics study has been performed on face centered cubic structured thorium to determine its melting temperature at room pressure. The ion-electron interaction potential energy calculated as a function of temperature for three volumes (a0)3 and (1.02a0)3 and (1.04a0)3 increases gradually with temperature and undergoes a sharp jump at ~2200 K, ~2100 K and ~1800 K, respectively. Here, a0 = 5.043 Å is the equilibrium lattice parameter at 0 K obtained from ab-initio calculations. These jumps in interaction energy are treated as due to the onset of melting and corresponding temperatures as melting point. The melting point of 2100 K is close to the experimental value of 2023K. Further, the same has been verified by plotting the atomic arrangement evolved at various temperatures and corresponding pair correlation functions.

  8. Subchannel analysis for thorium-based advanced CANDU reactor

    International Nuclear Information System (INIS)

    This paper presents the subchannel thermal hydraulic analysis in different thorium loading modes, different power and different lifetime using ASSERT-PVV3R1, a subchannel computer code developed by ACEL, to determine the best loading mode from the point of view of subchannel thermal hydraulics. According to the results for subchannel the mass flux, void fraction and outset of dry power, a best loading mode is established from the point of view of being calm and security to power, i.e., the loading mode of ThO2 and SEU mixing in pellets is obviously better than the loading mode in which the only ThO2 is loaded in the internal eight rods. (authors)

  9. Potential of thorium use in the HTR reactor

    International Nuclear Information System (INIS)

    In this investigation, several types of reactors and fuel circulations are dealt with as they refer to the region of the Federal Republic of Germany and are compared with each other as to their need for uranium and their costs until 2100. This includes also an investigation covering the effects of a postponed application of uranium-saving reactors, a delayed reprocessing and two variants of the nuclear energy's contribution to electricity generation. After today's light water reactor (LWR) of the pressure water reactor type (DWR) and the sodium-cooled fast breeder (SBR) which is being developed, the technically rather developed helium-cooled high temperature reactor (HTR) is dealt with as another system. The high temperature reactor is, because of its high coolant temperatures, not only suitable as a nuclear power plant, but can also be used to substitute fossile energy sources on the heat market and is being developed in Germany also for use as process heat reactor for nuclear coal gasification. Here the application of nuclear energy is only considered with regard to the region of power generation. Besides the case of the LWR and HTR-operation without reprocessing and fuel recycling for all reactor systems, the calculations also take into consideration the case of the closed fuel recycling. While LWR and SBR are based on the uranium-plutonium-fuel recycling, the thorium-uranium fuel circulation is considered for the HTR with globular fuel elements. As investigations made until today are generally restricted to the system LWR/SBR and the uranium-plutonium circulation, a main concern of the investigations presented here is to show the potential of the Thorium-utilization in high-temperature reactors and to determine how this system can also be applied during the time period concerned to set up a nuclear energy strategy which is safe and profitable as far as the uranium supply is concerned. (orig./UA) 891 UA/orig.- 892 HIS

  10. Exposures from thorium contained in thoriated tungsten welding electrodes.

    Science.gov (United States)

    Jankovic, J T; Underwood, W S; Goodwin, G M

    1999-01-01

    Information provided in this article can be used for estimating the radiation dose associated with the use of thoriated tungsten electrodes in tungsten inert gas welding. Area and breathing zone concentrations of 232Th generated by welding and electrode sharpening along with particle size information; isotopic composition of electrodes from two domestic manufacturers and one European manufacturer; and process variables and estimates on the number of thoriated tungsten electrodes manufactured are presented. Past literature is reviewed and compared with the results of this study. Isotopic analysis of a nominal 2% thoriated electrode found 0.6 ppm +/- 0.4 ppm 230Th and less than 0.1 ppm 228Th. Analysis of a ceriated tungsten electrode and a lanthanated tungsten electrode for 232Th found 124 ppm and 177 ppm, respectively. Electrode consumption during welding was primarily the result of tip sharpening. Less than 3% of the weight loss was attributable to the welding process. The in-mask concentration of respirable thorium particulate in the welder's breathing zone was 0.002 x 10(-12) microCi 232Th/mL. The concentration of respirable thorium particulate from electrode sharpening was 1.3 x 10(-12) microCi 232Th/mL. The measured sharpening time was 20 sec per electrode. Estimates of the activity median aerodynamic diameters for the respirable fraction of the welding and electrode sharpening aerosols were 3.5 and 5 microns, respectively, when measured in the breathing zone at 0.3 m (12 inches) from the point of operation. The respirable fraction of the total welding and sharpening aerosols was 45 and 60%. PMID:10386359

  11. Rasam Indian Restaurant: Menu

    OpenAIRE

    Rasam Indian Restaurant

    2013-01-01

    Rasam Indian Restaurant is located in the Glasthule, a suburb of Dublin and opened in 2003. The objective is to serve high quality, authentic Indian cuisine. "We blend, roast and grind our own spices daily to provide a flavour that is unique to Rasam. Cooking Indian food is founded upon long held family traditions. The secret is in the varying elements of heat and spices, the tandoor clay oven is a hugely important fixture in our kitchen. Marinated meats are lowered into the oven on long m...

  12. [Indian workers in Oman].

    Science.gov (United States)

    Longuenesse, E

    1985-01-01

    Until recently Oman was a country of emigration, but by 1980 an estimated 200,000 foreign workers were in the country due to the petroleum boom. Almost 1/3 of the estimated 300,000 Indian workers in the Gulf states were in Oman, a country whose colonial heritage was closely tied to that of India and many of whose inhabitants still speak Urdu. The number of work permits granted to Indians working in the private sector in Oman increased from 47,928 in 1976 to 80,787 in 1980. An estimated 110,000 Indians were working in Oman in 1982, the great majority in the construction and public works sector. A few hundred Indian women were employed by the government of Oman, as domestics, or in other capacities. No accurate data is available on the qualifications of Indian workers in Oman, but a 1979 survey suggested a relatively low illiteracy rate among them. 60-75% of Indians in Oman are from the state of Kerala, followed by workers from the Punjab and the southern states of Tamil Nadu and Andhra Pradesh and Bombay. Indian workers are recruited by specialized agencies or by friends or relatives already employed in Oman. Employers in Oman prefer to recruit through agencies because the preselection process minimizes hiring of workers unqualified for their posts. Officially, expenses of transportation, visas, and other needs are shared by the worker and the employer, but the demand for jobs is so strong that the workers are obliged to pay commissions which amount to considerable sums for stable and well paying jobs. Wages in Oman are however 2 to 5 times the level in India. Numerous abuses have been reported in recruitment practices and in failure of employers in Oman to pay the promised wages, but Indian workers have little recourse. At the same level of qualifications, Indians are paid less then non-Omani Arabs, who in turn receive less than Oman nationals. Indians who remain in Oman long enough nevertheless are able to support families at home and to accumulate considerable

  13. Recovery of protactinium-231 and thorium-230 from cotter concentrate: pilot plant operatins and process development

    Energy Technology Data Exchange (ETDEWEB)

    Hertz, M.R.; Figgins, P.E.; Deal, W.R.

    1983-02-10

    The equipment and methods used to recover and purify 339 g of thorium-230 and 890 mg of protactinium-231 from 22 of the 1251 drums of Cotter Concentrate are described. The process developed was (1) dissolution at 100/sup 0/C in concentrated nitric acid and dilution to 2 to 3 molar acid, (2) filtration to remove undissolved solids (mostly silica filter aid), (3) extraction of uranium with di-sec-butyl-phenyl phophonate (DSBPP) in carbon tetrachloride, (4) extraction of both thorium and protactinium with tri-n-octylphosphine oxide (TOPO) in carbon tetrachloride followed by selective stripping of the thorium with dilute of sulfuric acid, (5) thorium purification using oxalic acid, (6) stripping protactinium from the TOPO with oxalic acid, and (7) protactinium purification through a sequence of steps. The development of the separation procedures, the design of the pilot plant, and the operating procedures are described in detail. Analytical procedures are given in an appendix. 8 figures, 4 tables.

  14. Recovery of protactinium-231 and thorium-230 from cotter concentrate: pilot plant operatins and process development

    International Nuclear Information System (INIS)

    The equipment and methods used to recover and purify 339 g of thorium-230 and 890 mg of protactinium-231 from 22 of the 1251 drums of Cotter Concentrate are described. The process developed was (1) dissolution at 1000C in concentrated nitric acid and dilution to 2 to 3 molar acid, (2) filtration to remove undissolved solids (mostly silica filter aid), (3) extraction of uranium with di-sec-butyl-phenyl phophonate (DSBPP) in carbon tetrachloride, (4) extraction of both thorium and protactinium with tri-n-octylphosphine oxide (TOPO) in carbon tetrachloride followed by selective stripping of the thorium with dilute of sulfuric acid, (5) thorium purification using oxalic acid, (6) stripping protactinium from the TOPO with oxalic acid, and (7) protactinium purification through a sequence of steps. The development of the separation procedures, the design of the pilot plant, and the operating procedures are described in detail. Analytical procedures are given in an appendix. 8 figures, 4 tables

  15. The EC thematic network on the analysis of thorium and its isotopes in workplace materials

    International Nuclear Information System (INIS)

    Accurate measurements of workplace exposure to 232Th and its progeny are required to estimate internal radiation doses received by persons working with thorium-containing materials. However, a small intercomparison carried out in the mid-nineteen nineties raised doubts about the reliability of results obtained by methods available for measurement of thorium. An EC-funded thematic network was therefore established to bring together experts in the field of thorium analysis in order to coordinate research activity and identify best analytical practice, requirements for reference materials, etc. This network has now successfully completed its work programme, which included a survey to determine future research needs; a series of intercomparisons to test the performance of methods for measuring thorium in workplace materials, and a workshop held to promote best practice and transfer information to regulatory authorities and industry. Results of the work have been used to make various recommendations concerning future needs in this field. (author)

  16. Thorium concentration in human tissues from two geographic locations of the United States

    International Nuclear Information System (INIS)

    The naturally occurring alpha-emitting isotopes of thorium (Th-228, Th-230 and Th-232) have been determined in 22 sets of human tissue samples obtained at autopsy from Grand Junction, Colorado and 10 sets from Washington, DC. Lung, pulmonary lymph nodes, liver, kidney, bone and spleen were obtained for most cases. Personal data for each individual's age, sex, smoking history and occupation were obtained whenever possible. Thorium was determined by a procedure utilizing solvent extraction and alpha-spectrometry following tissue digestion and coprecipitation of thorium with iron. Th-229 was used as an internal tracer. The concentration of thorium isotopes is as follows: lymph nodes > lung > bone > kidney > liver for Th-230 and Th-232 and lymph nodes > bone > lung > kidney > liver for Th-228. The organ distributions are discussed in relation to geochemical abundances, metabolism and physico-chemical forms of the sources

  17. Thorium, and the problems posed for incorporation monitoring. Applications, measurements, evaluation and interpretation

    International Nuclear Information System (INIS)

    The natural element thorium is widespread due to its technical application. The extremely low annual limits of intakes (ALI-inhalation) laid down in the Radiation Protection Ordinance, the amended version of the related guidelines, and the draft basic standards of radiation protection from the European Communities make very high requirements on the monitoring of occupationally exposed workers. The detection of thorium within the body or excretions is extremely difficult and time-consuming. Additional problems are caused by lacking information on the biokinetics of thorium and its decay products. The new draft guidelines regarding the monitoring of incorporations were discussed during the seminar with ragard to the detection methods, the biokinetics of thorium and its decay products, and the estimate of exposures. The present report gives a summary of the discussions adn defines the need of research. The twelve papers and two annexes to the proceedings have been prepared for separate retrieval from the database. (orig./HP)

  18. Determination of trace thorium in triuranium octoxide by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    In nuclear industry, trace thorium in uranium product from mining and metallurgy is an important impurity. It is difficult to separate and analyze trace thorium in uranium product. It has important significance to improve of the quality of uranium product in our country that this problem is solved and applied to the production. A method was developed for determining the trace thorium in triuranium octoxide by ID-ICP-MS. The detection limit of this method is 0.003 3 μg/g(3s), and sr is less than 3%(n=3). The results of the determination are in good agreement with the reference values in standard reference materials GBW04205, GBW04242 and GBW04243. These indicate that the method is a sensitive and accurate one and can meet the demand for trace thorium analysis in triuranium octoxide. (authors)

  19. Determination of traces of thorium in uranium by inductively coupled plasma mass spectrometry (ICP-MS)

    International Nuclear Information System (INIS)

    An analytical methodology for the determination of traces of thorium in uranium oxide by Inductively Coupled Plasma Mass Spectrometry has been developed. Recovery studies were carried out by standard addition and also by tracer technique to validate the methodology. (author)

  20. High-temperature properties of thorium dioxide: A first-principles molecular dynamics study

    Science.gov (United States)

    Nakamura, Hiroki; Machida, Masahiko

    2016-09-01

    Thorium has been considered a potential nuclear fuel for decades. To develop evaluation method for high-temperature properties of thorium dioxide as a candidate nuclear fuel, we perform first-principles molecular dynamics. The calculated enthalpy and thermal expansion agree well with the observed data. The Bredig transition temperature also coincides with experiments. Our results indicate that this method can provide reliable data of thermal properties of nuclear fuels.

  1. Electronic energy transfer between coumarin 460 and Eu3+ in thorium phosphate xerogel

    International Nuclear Information System (INIS)

    Optical spectroscopy experiments performed on thorium phosphate xerogels, doped with both a laser dye (coumarin 460) and europium, have pointed out the existence of an electronic energy transfer from coumarin 460 to the 5D3 level of Eu3+. Indeed, the excitation spectrum of the red fluorescence of Eu3+ in thorium phosphate xerogel doped simultaneously with coumarin 460 exhibits a broad band corresponding to the absorption of coumarin 460 in this optical region

  2. The application of research reactor Maria for analysis of thorium use in nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Chwaszczewski, S.; Andrzejewski, K.; Myslek-Laurikainen, B.; Pytel, B.; Szczurek, J. [Dep. Thorium Project, Institute of Atomic Energy POLATOM, 05-400 Otwock-Swierk (Poland); Polkowska-Motrenko, H. [Institute of Nuclear Chemistry and Technology, ul.Dorodna 16 03-195 Warszawa (Poland)

    2010-07-01

    The MARIA reactor, pool-type light-water cooled and beryllium moderated nuclear research reactor was used to evaluate the {sup 233}U breeding during the experimental irradiation of the thorium samples. The level of impurities concentrations was determined using ICP-MS method. The associated development of computer programs for analysis of application of thorium in EPR reactor consist of PC version of CORD-2/GNOMER system are presented. (authors)

  3. Radiochemical separation of thorium from 18O induced reaction with natural uranium

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A radiochemical procedure used to separate and purify trace concentra tion thorium produced in heavy ion reaction with uranium targets is presented. The procedure can rapidly yield thorium fraction suitable for gamma-ray spectroscopy studies. The resultant gamma-ray spectra showed that Th was isolated from a large number of elements produced in the reaction, and there were only a few contaminat ing activities of isotopes of Sc, Cd, In, etc. The decontamination factors for the main reaction products are given.

  4. Uranium and thorium distribution in soils and weathered bedrock in south Texas

    Science.gov (United States)

    Dickinson, Kendell A.

    1977-01-01

    The distribution of uranium and thorium in soils and weathered bedrock in areas of calich soil development on various kinds of sedimentary bedrock in south Texas indicates that uranium and thorium are leached from the surface layers and deposited deeper in the soil or weathered bedrock. The data provide field evidence that uranium is mobilized during dry-climate weathering, and suggest that caution be used in the interpretation of airborne, radioactive surveys that measure uranium at the surface.

  5. Thorium-based fuel cycles: reassessment of fuel economics andproliferation risk

    OpenAIRE

    Serfontein, Dawid E.; Mulder, Eben J.

    2014-01-01

    At current consumption and current prices, the proven reserves for natural uranium will last only about 100 years. However, the more abundant thorium, burned in breeder reactors, such as large High Temperature Gas-Cooled Reactors, and followed by chemical reprocessing of the spent fuel, could stretch the 100 years for uranium supply to 15,000 years. Thorium-based fuel cycles are also viewed as more proliferation resistant compared to uranium. However, several barriers to entry caused all coun...

  6. Feasibility Study of 1/3 Thorium-Plutonium Mixed Oxide Core

    OpenAIRE

    2014-01-01

    Thorium-plutonium mixed oxide (Th-MOX) fuel has become one of the most promising solutions to reduce a large and increasing plutonium stockpile. Compared with traditional uranium-plutonium mixed oxide (U-MOX) fuels, Th-MOX fuel has higher consumption rate of plutonium in LWRs. Besides, thorium based fuels have improved thermomechanical material properties compared with traditional U-MOX fuels. Previous studies on a full Th-MOX core have shown reduced efficiency in reactivity control mechanism...

  7. A Computational Analysis of Thorium Dioxide and Th(1-x)UxO2 Systems

    OpenAIRE

    A. E. Shields

    2015-01-01

    Nuclear power generation is an important way to satisfy rising global energy needs without increasing dependence on coal and petroleum. However, conventional nuclear fuels, such as uranium and plutonium dioxides, raise several safety concerns. Many countries have shown a renewed interest in thorium-based fuels as a potentially safer alternative. Thorium dioxide requires small amounts of a neutron source, such as uranium or plutonium, to generate a sustainable fission reaction. Due to the haza...

  8. Optimisation Studies of Accelerator Driven Fertile to Fissile Conversion Rates in Thorium Fuel Cycle

    OpenAIRE

    Bungau, Cristian; Barlow, Roger; Cywinski, R.

    2012-01-01

    The need for proliferation-resistance, longer fuel cycles, higher burn up and improvedwaste form characteristics has led to a renewed worldwide interest in thorium-based fuels and fuel cycles. In this paper the GEANT4 Monte Carlo code has been used to simulate the Thorium-Uranium fuel cycle. The accelerator driven fertile to fissile conversion rates have been calculated for various geometries. Several new classes have been added by the authors to the GEANT4 simulation ...

  9. Landscape control of uranium and thorium in boreal streams : spatiotemporal variability and the role of wetlands

    OpenAIRE

    F. Lidman; C. M. Mörth; H. Laudon

    2012-01-01

    The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2) up to a fourth-order stream (67 km2). Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to ...

  10. X-Ray Fluorescence Spectrometry. I. Determination of thorium in ores

    International Nuclear Information System (INIS)

    A X-ray spectrometric method has been developed for analysis of thorium in ores in the range of concentration from 0.01 to 0.5 percent ThO2, using selenium as a internal standard. The concentration of thorium is determined in a working curve prepared by plotting the percentage of ThO2 against the ratio intensity of the Th Lα1 line to Sekβ1 line. (Author) 17 refs

  11. Establishing bounding internal dose estimates for thorium activities at Rocky Flats.

    Science.gov (United States)

    Ulsh, Brant A; Rich, Bryce L; Chew, Melton H; Morris, Robert L; Sharfi, Mutty; Rolfes, Mark R

    2008-07-01

    As part of an evaluation of a Special Exposure Cohort petition filed on behalf of workers at the Rocky Flats Plant, the National Institute for Occupational Safety and Health (NIOSH) was required to demonstrate that bounding values could be established for radiation doses due to the potential intake of all radionuclides present at the facility. The main radioactive elements of interest at Rocky Flats were plutonium and uranium, but much smaller quantities of several other elements, including thorium, were occasionally handled at the site. Bounding potential doses from thorium has proven challenging at other sites due to the early historical difficulty in detecting this element through urinalysis methods and the relatively high internal dose delivered per unit intake. This paper reports the results of NIOSH's investigation of the uses of thorium at Rocky Flats and provides bounding dose reconstructions for these operations. During this investigation, NIOSH reviewed unclassified reports, unclassified extracts of classified materials, material balance and inventory ledgers, monthly progress reports from various groups, and health physics field logbooks, and conducted interviews with former Rocky Flats workers. Thorium operations included: (1) an experimental metal forming project with 240 kg of thorium in 1960; (2) the use of pre-formed parts in weapons mockups; (3) the removal of Th from U; (4) numerous analytical procedures involving trace quantities of thorium; and (5) the possible experimental use of thorium as a mold coating compound. The thorium handling operations at Rocky Flats were limited in scope, well-monitored and documented, and potential doses can be bounded. PMID:18545032

  12. The evolutionary adoption of thorium beginning with its application in niche LWR fuels

    International Nuclear Information System (INIS)

    Since the inception of nuclear energy, the use of thorium as a nuclear fuel has been envisioned. Thorium boasts benefits, however, drawbacks which are both economic and technical including its the lack of a naturally occurring fissile isotope implies that its utility is inherently more difficult. The implementation of thorium as a nuclear fuel requires that it must provide sound technical advantages in combination with attractive economics as compared to standard uranium fuel. Revolutionary thorium concepts such as molten salt reactors and accelerator driven systems may provide theoretical merit, however, their exotic nature and associated technical challenges label them as long-term solutions at best. A near-to-medium term solution for thorium must be based on an evolutionary approach utilizing light/heavy water reactor platforms. While thorium does not provide a near-to-medium term complete replacement of uranium, it does provide substantial benefit within niche applications. To license and bring to market these niche fuels, Thor Energy and an international consortium of entities (including: Fortum, KAERI, Westinghouse, NNL, ITU, IFE, and a few other minor entities) have initiated a fuel development and irradiation test program to characterize the performance of these thoria-containing fuels. (author)

  13. Photochemical precipitation of thorium and cerium and their separation from other ions in aqueous solution.

    Science.gov (United States)

    Das, M; Heyn, A H; Hoffman, M Z; Agarwal, R P

    1970-10-01

    Thorium was precipitated from homogeneous solution by exposing solutions of thorium and periodate in dilute perchloric acid to 253.7 nm radiation from a low-pressure mercury lamp. Periodate is reduced photochemically to iodate which causes the formation of a dense precipitate of the basic iodate of thorium(IV). The precipitate was redissolved, the iodate reduced, the thorium precipitated first as the hydroxide, then as the oxalate and ignited to the dioxide for weighing. Thorium(IV) solutions containing 8-200 mg of ThO(2) gave quantitative results with a standard deviation (s) of 0.2 mg. Separations from 25 mg each of iron, calcium, magnesium, 50 mg of yttrium and up to 500 mg of uranium(VI) were quantitative (s = 0.25 mg). Separations from rare earths, except cerium, were accomplished by using hexamethylenetetramine rather than ammonia for the precipitation of the hydroxide. Cerium(III) was similarly precipitated and converted into CeO(2) for weighing. Quantitative results were obtained for 13-150 mg of CeO(2) with a standard deviation of 0.2 mg. Separations from 200 mg of uranium were quantitative. Other rare earths and yttrium interfered seriously. The precipitates of the basic cerium(IV) and thorium iodates obtained are more compact than those obtained by direct precipitation and can be handled easily. Attempts to duplicate Suzuki's method for separating cerium from neodymium and yttrium were not successful. PMID:18960820

  14. Thorium and uranium in soil fractions and certain macromycete species in boreal forest ecosystems

    Directory of Open Access Journals (Sweden)

    M. M. Vinichuk

    2012-07-01

    Full Text Available The content of thorium (Th and uranium (U in fractions of soil edaphosphere, rhizosphere, rhizoplane, fungal mycelium and fruit bodies were investigated. The concentrations of thorium in edaphosphere and rhizosphere fractions and mycelia of fungi are not different significantly and vary in the range of 0.74–1.45 mg kg–1 dry matter. The concentration of thorium in the rhizoplane fraction is 4 times lower than in the bulk soil – edaphosphere. The concentrations of uranium in edaphosphere, rhizosphere and rhizoplane fractions and fungi mycelium are not significantly different and vary between 3.11 and 9.36 mg kg–1 dry matter. The content of the studied natural isotopes in fruit bodies of fungi is 270 times lower than in the bulk soil: biological absorption coefficients of uranium and thorium in fruit bodies are on average 0.035 and 0.006, respectively. The contents of thorium and uranium in fungal mycelium and fruit bodies increase with increasing their concentrations in the soil. It is shown that in the fungi mycelium of the upper (0–5 cm layer of forest soil can be allocated 2.0–5.0 and 1.4–2.7 % of the total thorium and uranium soil content, respectively.

  15. Comparison of the radiological hazard of thorium and uranium spent fuels from VVER-1000 reactor

    Science.gov (United States)

    Frybort, Jan

    2014-11-01

    Thorium fuel is considered as a viable alternative to the uranium fuel used in the current generation of nuclear power plants. Switch from uranium to thorium means a complete change of composition of the spent nuclear fuel produced as a result of the fuel depletion during operation of a reactor. If the Th-U fuel cycle is implemented, production of minor actinides in the spent fuel is negligible. This is favourable for the spent fuel disposal. On the other hand, thorium fuel utilisation is connected with production of 232U, which decays via several alpha decays into a strong gamma emitter 208Tl. Presence of this nuclide might complicate manipulations with the irradiated thorium fuel. Monte-Carlo computation code MCNPX can be used to simulate thorium fuel depletion in a VVER-1000 reactor. The calculated actinide composition will be analysed and dose rate from produced gamma radiation will be calculated. The results will be compared to the reference uranium fuel. Dependence of the dose rate on time of decay after the end of irradiation in the reactor will be analysed. This study will compare the radiological hazard of the spent thorium and uranium fuel handling.

  16. Ishi: A Yahi Indian.

    Science.gov (United States)

    2003

    The Yahi Indians were part of a larger tribal group called the Yana. The Yahi way of life, along with the lives of many other California Indian groups, changed when European and U.S. settlers came to California. In 1872 Ishi and his family were the last of the Yahi living in the Deer Creek (California) area. By 1911 Ishi was the last surviving…

  17. A follow-up study on the relationship between thorium lung burden and health effects on miners (1982-91)

    International Nuclear Information System (INIS)

    The results of an investigation on the natural thorium lung burden and its health effects on miners in the Baiyan Obo mine are reported. An electrostatic collection system was used to measure the exhaled thoron activity. Measurements of exhaled thoron activity were carried out on 588 miners (985 measurements) who had inhaled thorium-containing dusts. Exhaled thoron activity was also determined on 124 persons (124 measurements), who had not inhaled thorium-containing dusts. The average thorium lung burdens of the 588 miners and the 124 controls were 0.85 Bq and 0.15 Bq, respectively. Of the 588 miners, 7 had a thorium lung burden higher than 3.7 Bq, 5 had a thorium lung burden higher than 4.44 Bq and 1 miner had the highest thorium lung burden of 5.56 Bq. In about 20% of these miners the thorium lung burden was 0.74 Bq. There was no definite increase in the incidence of lung cancers in more than 2000 miners who had inhaled thorium dusts and thoron daughters in the period 1958-90. Of the miners who had inhaled thorium dusts, there was a significant increase in the incidence of respiratory symptoms, lung function disorders and pneumoconiosis stage 0+ and stage 1. Based on the results of animal experiments and the low percentage of thorium in the dust, the authors suggest that disorders of the respiratory tract were due mainly to other chemical components in the dust, such as SiO2 and other chemical elements. The role of thorium is negligible. (author)

  18. Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

    Directory of Open Access Journals (Sweden)

    H. Laudon

    2012-03-01

    Full Text Available The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, but could not explain the variability in the export. Instead, the extent of lakes and mires within each subcatchment was found to be a stronger predictor for the transport of uranium and thorium. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal mires. Approximately 65–80 % of uranium and 55–65 % of thorium entering a mire is estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands is estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40 %. The atmospheric deposition of uranium and thorium was also quantified and its contribution to boreal streams was found to be low compared to weathering.

  19. Rapid and non-destructive determination of uranium and thorium by gamma spectrometry and a comparison with ICP-AES

    International Nuclear Information System (INIS)

    A rapid, simple and non-destructive method was developed for the determination of thorium, uranium by gamma ray spectrometry (high purity Ge detector) in thorium-uranium mixture. Using the calibration curves, thorium and uranium were analyzed in synthetic samples with RSD ∼2 %. Inter element effect suggested that 583 and 185.7 keV gamma lines are more suitable for the determination of Th and U, respectively in a mixture of Th-U. The newly developed method was validated by routinely employed method using synthetic samples. An ICP-AES based method was developed for the determination of uranium and thorium for comparison purpose. (author)

  20. Accident analysis of heavy water cooled thorium breeder reactor

    Science.gov (United States)

    Yulianti, Yanti; Su'ud, Zaki; Takaki, Naoyuki

    2015-04-01

    Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of nuclear reactor accidents types examined here is Unprotected Transient over Power (UTOP) due to withdrawing of the control rod that result in the positive reactivity insertion so that the reactor power will increase rapidly. Another accident type is Unprotected Loss of Flow (ULOF) that caused by failure of coolant pumps. To analyze the reactor accidents, neutron distribution calculation in the nuclear reactor is the most important factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The power reactor has a peak value before reactor has new balance condition

  1. Profile: American Indian/Alaska Native

    Science.gov (United States)

    ... Minority Population Profiles > American Indian/Alaska Native Profile: American Indian/Alaska Native Spotlight ACA Infographic for American Indians/ ... Program Circle of Life multimedia youth education program American Indian/Alaska Native Profile Great Plains Area Alaska Area ...

  2. Resources of thorium toward alternatives power plant in Indonesia: a concept of implementation

    International Nuclear Information System (INIS)

    Indonesia is on the verge of energy crisis. We need at least additional 35 GW(e) new power plant in order to sustain economic growth competitively. There are many problems in realizing this demand, especially lack of infrastructure, building permits, and depletion of primary natural resources for energy etc. One of the option to look at it, is the use of nuclear power plant (NPP). However, NPP is still considered as the last option in the energy mix. Even that, the use of Uranium-based NPP such as Light Water Reactor (LWR) technology requires Uranium enrichment. Indonesia is not in the position of doing the enrichment ourselves. Therefore, option of using LWR type of reactors is not a wise one. Different approach is sought using Thorium-based NPP. Whereas thorium does not require enrichment. Thorium is also abundant in the country. This paper will discuss our approach and strategy to use thorium as an alternative in NPP. The type of reactor being considered is Thorium Molten Salt Reactor (TMSR) type of technology. It looks that thorium approach receives welcome and blessing from the Government and the people of Indonesia. The criteria being set for using thorium based NPP are: cheap, clean, safe, and reliable. Cheap means cheaper than coal. Clean means no polluted emission being produced - green nuclear, safe means no accident could occur based on regular design basis accident (DBA) and beyond of LWR type technology, reliable means high capacity factor. Based upon these criteria would make national energy policy to become sustainable

  3. Automated refueling simulations of a CANDU for the exploitation of thorium fuels

    Science.gov (United States)

    Holmes, Bradford

    CANDU nuclear reactors are in a unique circumstance where they are able to utilize and exploit a number of different fuel options to provide power as a utility. Thorium, a fertile isotope found naturally, is one option that should be explored. Thorium is more abundant than uranium, which is the typical fuel in the reactor and the availability of thorium makes nuclear energy desirable to more countries. This document contains the culmination of a project that explores, tests, and analyzes the feasibility of using thorium in a CANDU reactor. The project first develops a set of twodimensional lattice and three dimensional control rod simulations using the DRAGON Version 4 nuclear physics codes. This step is repeated for many concentrations of thorium. The data generated in these steps is then used to determine a functional enrichment of thorium. This is done via a procedural elimination and optimization of certain key parameters including but not limited to average exit burnup and reactivity evolution. For the purposes of this project, an enrichment of 1 % thorium was found viable. Full core calculations were done using the DONJON 4 code. CANFUEL, a program which simulates the refueling operations of a CANDU reactor for this fuel type was developed and ran for a simulation period of one hundred days. The program and the fuel selection met all selected requirements for the entirety of the simulation period. CANFUEL requires optimization for fuel selection before it can be used extensively. The fuel selection was further scrutinized when a reactivity insertion event was simulated. The adjuster rod 11 withdrawal from the core was analyzed and compared to classical CANDU results in order to ensure no significant deviations or unwanted evolutions were encountered. For this case, the simulation results were deemed acceptable with no significant deviations from the classical CANDU case.

  4. Mission Indians and Indians of California Land Claims.

    Science.gov (United States)

    Shipek, Florence C.

    1989-01-01

    Discusses California Indian Claims Cases, focussing on the Indians of California Case. Presents a background sketch of the major claims and the nature of influences determining the wording of petitions, particularly in the Missions Indian Claims Case in which anthropological misunderstanding of socio-political-territorial organizations created…

  5. Combustion synthesis and characterization of uranium and thorium tellurides

    International Nuclear Information System (INIS)

    This report describes an investigation of the chemical systems uranium-tellurium and thorium-tellurium. A novel synthesis technique, combustion synthesis, which uses the exothermic heat of reaction rather than externally supplied heat, was utilized to form the phases UTe, U3Te4, and UTe2 in the U-Te system and the phases ThTe, Th2Te3, and ThTe2 in the Th-Te system from reactions of the type U/sub x/ + Te/sub y/ = U/sub x/Te/sub y/. With this synthetic method, U-Te and Th-Te products could be formed in a matter of seconds, and the purity of the products was often greater than that of the starting materials used. Control over final product stoichiometry was found to be very difficult. The product phase distribution observed in combustion products, as determined by x-ray diffraction, electron microprobe, and optical metallographic methods, was found to be spatially complex. Lattice constants were calculated from x-ray diffraction patterns for the compounds UTe, U3Te4, and ThTe. SOLGASMIX thermodynamic equilibrium calculations were performed using available and estimated thermodynamic data on the system U-Te-O in an attempt to understand the products formed by combustion. Adiabatic combustion reaction temperatures for specific U-Te and Th-Te reactions were also calculated utilizing available and estimated thermodynamic data. 71 refs., 31 figs., 15 tabs

  6. Uranium and thorium in urban park soils of Sao Paulo

    International Nuclear Information System (INIS)

    The Environmental Protection Agency of the State of Sao Paulo (CETESB) has reported the Quality Reference Value (VRQ) for soils in Sao Paulo, which is the concentration of a substance in the soil or groundwater which defines groundwater quality and clean soil, for several elements. Nevertheless, there is no information about U and Th concentrations. In the present paper, which is part of a main project that assesses metals in urban park soils of Sao Paulo city, the concentration of U and Th were determined in surface soil samples of fourteen city public parks. Instrumental Neutron Activation Analysis (INAA) was used for analysis. The U and Th range concentrations obtained were: 1.9 to 8.6 mg kg-1 for U and 8.4 to 38.0 mg kg-1 for Th. The U and Th range concentrations obtained are significantly higher compared to NASC values (2.7 mg kg-1 for U and 12 mg kg-1 for Th), but they are in the same order of magnitude of other studies reported in the literature. The uranium and thorium concentrations in Sao Paulo park soils may be attributed to lithology of Sao Paulo. On the other hand, high uranium concentrations (up to hundreds of ppm) have been reported in the literature in fertilizers containing phosphate, which may have contributed to the uranium levels in the park soils, due to the park garden maintenance. (author)

  7. Irradiation performance of thorium oxide based coated particle fuels

    International Nuclear Information System (INIS)

    BISO coated ThO2 particles as fertile fuel and BISO or TRISO coated (Th, U)O2 particles as fissile fuel for a High-temperature Gas-cooled Reactor (HTGR) were irradiated to investigate particle performances in loosely-packed condition of two capsules in JRR-2 and one capsule in JMTR. Irradiation of these coated particles was achieved to a maximum fast neutron fluence of 2.22 x 1021 neutrons/cm2 (E > 0.18 MeV) and a maximum thermal neutron fluence of 1.35 x 1021 neutrons/cm2 at temperatures of 770 to 1225 deg C. And a maximum burnup of fissile particles was 2.42 % FIMA. It was found in the post-irradiation examinations that the coated particles were intact except a little of the BISO coated fissile particles, and the thorium oxide based coated particles performed well under the irradiation conditions. The data were also taken on the fission product behavior released from the fuel kernels during the irradiation. And density of the outer LTIPyC (OPyC) increased as increasing the fluence of fast neutron. As a result of the densification of the OPyC, the crushing strength of the BISO coated particles increased, otherwise the TRISO coated particles decreased. (author)

  8. Stability of dilute solutions of uranium, lead, and thorium ions

    Science.gov (United States)

    Milkey, R.G.

    1954-01-01

    Standard solutions and samples containing a few micrograms of metallic ions per milliliter are frequently used in determination of trace elements. It is important to know whether the concentrations of such solutions remain constant from day to day. The stability of dilute solutions of three metallic ions-uranium, lead, and thorium-has been investigated. Solutions containing concentrations of metallic ions, ranging from 1000 to 0.1 ?? per milliliter, were allowed to stand for approximately 2.5 months, and then the metallic ion content of those solutions that had lost strength was determined. Both adsorption and hydrolysis variously influenced the solute loss, but the minimum pH at which loss of concentration of lead and uranium occurred seemed to coincide with the pH at which the hydrolyzed metal ions began to precipitate. No increase in the stability of the solutions was obtained by substituting polyethylene containers for borosilicate glass. The solutions that lost strength could not be restored promptly to the original concentration by manual means, such as shaking them vigorously for several minutes.

  9. Uranium and thorium contents in bottled mineral waters

    International Nuclear Information System (INIS)

    Thirty-four types of mineral waters bottled in Japan and 42 types of foreign mineral waters were analyzed especially for U and Th by ICP-MS. Japanese bottled waters exhibited rather low U concentrations below its detection limit of 2 ng/L up to 1.3 μ g/L. They are all below the Japanese water standard for U concentration. Foreign bottles showed a wide range of U contents up to 16 μ g/L and smaller Th contents up to 30 ng/L. Apparently, some foreign mineral waters contained a large amount of U exceeding the Japanese water standard. In spite of this, such mineral waters may be used as a readily-available uranium (and thorium) sample solution. Other various aquatic samples such as rainwater, lake water, river water, and tap water were also analyzed for U and Th. In Japan, U concentrations are of the order of several to several tens of ng/L for various samples in general, which is in accordance with those of bottled mineral waters. Uranium concentrations may be used as a key for environmental monitoring, as exemplified by water of Ashida River, Hiroshima Prefecture. (author)

  10. Study on thorium recovery from bastnaesite treatment process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongqi; XU Yang; HUANG Xiaowei; LONG Zhiqi; CUI Dali; HU Feng

    2012-01-01

    Thorium (Th) stripping behavior from HEH/EHP (2-(ethylhexyl) phosphoric acid mono-2-ethylhexyl ester) with H2SO4,HCl and HNO3 were investigaated.The results indicated that H2SO4 was the most effective stripping reagent compared with HCl and HNO3.Selecting H2SO4 as the stripping reagent,the effect of phase ratio,acidity,H2SO4 amount,HEH/EHP concentration and Th loading in HEH/EHP on Th stripping were systematically investigated.As a result,the optimum stripping conditions of Th(Ⅳ) were obtained as the concentration of H2SO4 solution was 3.50 mol/L,phase ratio was 4∶1.Low HEH/EHP concentration was benefit for Th stripping.Based on the results,pilot test for new Bastnaesite treatment process was carried out and the recovery of Ce,F and Th were more than 99%,98% and 95% separately.

  11. Ion source development for ultratrace detection of uranium and thorium

    Science.gov (United States)

    Liu, Y.; Batchelder, J. C.; Galindo-Uribarri, A.; Chu, R.; Fan, S.; Romero-Romero, E.; Stracener, D. W.

    2015-10-01

    Efficient ion sources are needed for detecting ultratrace U and Th impurities in a copper matrix by mass spectrometry techniques such as accelerator mass spectrometry (AMS). Two positive ion sources, a hot-cavity surface ionization source and a resonant ionization laser ion source, are evaluated in terms of ionization efficiencies for generating ion beams of U and Th. The performances of the ion sources are characterized using uranyl nitrate and thorium nitrate sample materials with sample sizes between 20 and 40 μg of U or Th. For the surface ion source, the dominant ion beams observed are UO+ or ThO+ and ionization efficiencies of 2-4% have been obtained with W and Re cavities. With the laser ion source, three-step resonant photoionization of U atoms has been studied and only atomic U ions are observed. An ionization efficiency of about 9% has been demonstrated. The performances of both ion sources are expected to be further improved.

  12. Study of an ADS Loaded with Thorium and Reprocessed Fuel

    Directory of Open Access Journals (Sweden)

    Graiciany de Paula Barros

    2012-01-01

    Full Text Available Accelerator-driven systems (ADSs are investigated for long-lived fission product transmutation and fuel regeneration. The aim of this paper is to investigate the nuclear fuel evolution and the neutronic parameters of a lead-cooled accelerator-driven system used for fuel breeding. The fuel used in some fuel rods was T232hO2 for U233 production. In the other fuel rods was used a mixture based upon Pu-MA, removed from PWR-spent fuel, reprocessed by GANEX, and finally spiked with thorium or depleted uranium. The use of reprocessed fuel ensured the use of T232hO2 without the initial requirement of U233 enrichment. In this paper was used the Monte Carlo code MCNPX 2.6.0 that presents the depletion/burnup capability, combining an ADS source and kcode-mode (for criticality calculations. The multiplication factor (keff evolution, the neutron energy spectra in the core at BOL, and the nuclear fuel evolution during the burnup were evaluated. The results indicated that the combined use of T232hO2 and reprocessed fuel allowed U233 production without the initial requirement of U233 enrichment.

  13. Chemical Speciation of Thorium in Marine Biogenic Particulate Matter

    Directory of Open Access Journals (Sweden)

    Katsumi Hirose

    2004-01-01

    Full Text Available Concentrations of particulate thorium in seawater were determined together with the strong organic ligand (SOL and uranium in particulate matter (PM. The concentrations of particulate Th in surface waters of the western North Pacific and the Sea of Japan ranged from 0.05 to 1.5 pM (1 x 10−12 M, and showed relatively large temporal and spatial variations. In order to chemically characterize the particulate Th in seawater, the relationship between particulate Th and SOL concentrations in surface PM was examined. The result reveals that particulate Th in surface PM was well correlated with the SOL concentration in PM. The concentrations of particulate Th in surface water were linearly related to those of particulate U. Mass balance analysis suggests that the dominant chemical form of Th(IV, as well as of U, in surface PM is a surface complex with the SOL in PM. Our findings suggest that the SOL in PM is a nonmetal-specific chelator originating from the cell surface of microorganisms.

  14. Thermodynamic investigations of oxyfluoride of thorium and uranium

    Science.gov (United States)

    Mukherjee, Sumanta; Dash, Smruti; Mukerjee, S. K.; Ramakumar, K. L.

    2015-10-01

    The standard molar Gibbs energy of formation of ThOF2(s) and UO2F2(s) has been determined using an e.m.f. technique. For this purpose, separate fluoride cell has been constructed using CaF2(s) as the solid electrolyte. From the measured e.m.f. values and required Gibbs energy data available in the literature, ΔfGom(T) for these oxyfluorides has been calculated. The enthalpy of formation of ThOF2(s) and UO2F2(s) at 298.15 K has been calculated from the experimentally measured Gibbs energy data using the second and the third law methods. To determine the stability domains of ThOF2(s) and UO2F2(s), the phase diagram and chemical potential diagrams of Th-F-O and U-F-O systems were calculated by the CALPHAD method and FactSage software. These calculations can be used to predict the oxygen partial pressures and the temperature domains in which thorium and uranium oxyfluorides might be formed in the molten salt medium.

  15. Ion Source Development for Ultratrace Detection of Uranium and Thorium

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuan [ORNL; Batchelder, Jon Charles [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Stracener, Daniel W [ORNL

    2015-01-01

    A hot-cavity surface ionization source and a hot-cavity laser ion source are evaluated in terms of ionization efficiencies for generating ion beams of U and Th. The work is motivated by the need for more efficient ion sources for detecting ultratrace U and Th impurities in a copper matrix by mass spectrometry techniques such as accelerator mass spectrometry (AMS). The performances of the ion sources are characterized using uranyl nitrate and thorium nitrate sample materials and sample sizes of 20 - 40 g of U or Th. For the surface source, the dominant ion beams observed are UO+ or ThO+ and ionization efficiencies of 2-4% have been obtained with W and Re cavities. Three-step resonant photoionization of U atoms is studied and an ionization efficiency of 8.7% has been obtained with the laser ion source. The positive ion sources promise more than an order of magnitude more efficient than conventional Cs-sputter negative ion sources used for AMS. In addition, the laser ion source is highly selective and effective in suppressing interfering and ions. Work is in progress to improve the efficiencies of both positive ion sources.

  16. Safeguards concept for the THTR-300 Thorium High Temperature Reactor

    International Nuclear Information System (INIS)

    The nuclear power plant in Hamm, Federal Republic of Germany is a plant with a high temperature reactor. The fuel elements are spheres with a diameter of 60 mm, an enrichment of 93%, a 235U content of 0.96 g and a thorium content of 10.2 g. The facility is divided into two material balance areas (MBA 1: fresh fuel and spent fuel storage; MBA 2: loading facility, reactor core and discharge facility) in order to increase the transparency of the fuel element flow, and because a direct physical inventory of the core is not possible. The inventory of the core is determined by the quantity received and the quantity withdrawn, which are to be reported to Euratom. The quantity received in the core will be verified by the inspectors using a special sampling machine. The quantity withdrawn from the core is counted by independent counters at the exit of the core. At the exit of the spent fuel storage a monitoring and logging system verifies all the drums leaving the storage. The route of the spent fuel drums is continuously observed by video systems until they are finally packed into shipping containers which are to be sealed by the operator using electronic seals. (author)

  17. Physics aspects of metal fuelled fast reactors with thorium blanket

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, D.K., E-mail: dina@igcar.gov.in; Singh, S.S.; Riyas, A.; Mohanakrishnan, P.

    2013-12-15

    Metal fuelled fast breeder reactors (MFBR) with high breeding ratio will play a major role in meeting the high nuclear power growth envisaged in India. In this regard several conceptual reactor designs with alloys of U–Pu–Zr fuel have been suggested for commercial operations. This study focusses on the physics design aspects of a sodium cooled U–Pu–6%Zr fuelled 1000 MWe fast breeder reactor, which can attain a breeding ratio of nearly 1.5. The calculation results on reactor kinetics and safety parameters of the 1000 MWe MFBR are presented. The changes in the breeding ratio by introduction of thorium in the blankets of the MFBR are also investigated. Burnup analyses are carried out to compare the core burnup effects in MOX and metal fuelled FBRs. Since the MOX fuelled 500 MWe prototype fast breeder is getting constructed at IGCAR, for burnup comparisons a MFBR of similar design is considered. The results of this study indicate that the loss of reactivity in the metal core with burnup is less than half that of a MOX core and its breeding ratio remains nearly constant. It is also found that the isotopic composition of plutonium (Pu-vector composition) remains more steady with burnup in a metal core.

  18. Reconnaissance for uranium and thorium in Alaska, 1954

    Science.gov (United States)

    Matzko, John J.; Bates, Robert G.

    1957-01-01

    During 1954 reconnaissance investigations to locate minable deposits of uranium and thorium in Alaska were unsuccessful. Areas examined, from which prospectors had submitted radioactive samples, include Cap Yakataga, Kodiak Island, and Shirley Lake. Unconcentrated gravels from the beach at Cape Yakataga average about 0.001 percent equivalent uranium. Uranothorianite has been identified by X-ray diffraction data and is the principal source of radioactivity in the Cape Yakataga beach sands studied; but the zircon, monazite, and uranothorite are also radioactive. The black, opaque uranothorianite generally occurs as minute euhedral cubs, the majority of which will pass through a 100-mesh screen. The bedrock source of the radioactive samples from Kodiak Island was not found; the maximum radioactivity of samples from the Shirley Lake area was equivalent to about 0.02 percent uranium. Radiometric traverses of the 460-foot level of the Garnet shaft of the Nixon Fork mine in the Nixon Fork mining district indicated a maximum of 0.15 mr/hr. In the Hot Springs district, drill hole concentrates of gravels examined contained a maximum of 0.03 percent equivalent uranium. A radioactivity anomaly noted during the Survey's airborne reconnaissance of portions of the Territory during 1954 is located in the Fairhaven district. A ground check disclosed that the radioactivity was due to accessory minerals in the granitic rock.

  19. Separation of thorium from uranium in monazite by precipitation method

    International Nuclear Information System (INIS)

    Previous researches have obtained the monazite processing stages and resulting Re(OH)3 as a product with ± 62% of recovery, and the by products obtained in the form of a compound of thorium (Th) and Uranium (U). For further utilization, studies of U and Th separation is needed. This research is aimed to determine the optimal conditions for the separation of Th from U in monazite using the precipitation method with H2SO4 as a reagent. Stages of the process in this research consisted of grinding, decomposition, partial dissolution, total dissolution, and precipitation of Th with H2SO4, Feed solution used for precipitation is obtained from total dissolution stage with 2 different reagents are H2SO4 and HCl. Parameters of the research include the precipitating reagent (H2SO4) consumption and precipitation time. Optimal recovery results in the precipitation of sulfate feed solution are Th = 96.99% and U = 18.26% with 20 ml of H2SO4 consumption and 30 minutes of precipitation time. Optimal recovery results in the precipitation of chloride feed solution are 98.05% and U 25.03% with 20 ml of H2SO4 consumption and 30 minutes of precipitation time. (author)

  20. Uranium, thorium, and lead systematics in Granite Mountains, Wyoming

    Science.gov (United States)

    Rosholt, J.N.; Bartel, A.J.

    1969-01-01

    Uranium, thorium and lead concentrations and isotopic compositions were determined on total rocks and a feldspar sample from widely separated parts of the Granite Mountains in central Wyoming. Linear relations defined by 206Pb/204Pb - 207Pb/204Pb and 208Pb/204Pb - 232Th/204Pb for the total rock samples define 2.8 billion-year isochrons. In contrast, 238U/206Pb ages are anomalously old by a factor of at least four. The low 238U/204Pb values, coupled with the radiogenic 206Pb/204Pb and radiogenic 207Pb/204Pb ratios, indicate that contents of uranium in near-surface rocks would have had to have been considerably greater than those presently observed to have generated the radiogenic lead. It is possible that more than 1011 kg of uranium has been removed from the Granite Mountains, and the most feasible interpretation is that most of this uranium was leached from near-surface rocks at some time during the Cenozoic, thus providing a major source for the uranium deposits in the central Wyoming basins. ?? 1969.

  1. Natural thorium isotopes in marine sediment core off Labuan port

    Energy Technology Data Exchange (ETDEWEB)

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600, Bangi, Selangor (Malaysia)

    2014-02-12

    Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on {sup 228}Th/{sup 232}Th model. The results suggest the {sup 230}Th and {sup 232}Th might be originated from terrestrial sedimentary rock while {sup 228}Th originated by authigenic origin. High ratio value of {sup 230}Th/{sup 232}Th detected at the top surface sediment indicates the increasing of {sup 230}Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using {sup 228}Th/{sup 232}Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

  2. Hamlin Garland and the Indian

    Science.gov (United States)

    Underhill, Lonnie E.

    1974-01-01

    Written to stimulate interest in an evaluation of Hamlin Garland's total production of work on the American Indian, this article suggests a reevaluation of some of Garland's work in light of the current interest in American Indian studies. (JC)

  3. Indian Ocean Traffic: Introduction

    Directory of Open Access Journals (Sweden)

    Lola Sharon Davidson

    2012-06-01

    Full Text Available Like the Mediterranean, the Indian Ocean has been a privileged site of cross-cultural contact since ancient times. In this special issue, our contributors track disparate movements of people and ideas around the Indian Ocean region and explore the cultural implications of these contacts and their role in processes that we would come to call transnationalization and globalisation. The nation is a relatively recent phenomenon anywhere on the globe, and in many countries around the Indian Ocean it was a product of colonisation and independence. So the processes of exchange, migration and cultural influence going on there for many centuries were mostly based on the economics of goods and trade routes, rather than on national identity and state policy.

  4. Indian Development vs Sino-Indian Relations

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ A deep, lasting, great friendship can be traced back to over two millennia ago between two close neighbors, the initiators of the world-famous Five Principles of Peaceful Co-existence with its 50th anniversary just commemorated this year. Historically, China benefited much from learning the brilliant Indian culture. Today, the two major Asian countries are learning from each other in their rapid economic growth. The rise of China and India, closer ties between the two, will definitely exert a significant impact on the Asia-Pacific region and the broader world in the days ahead.

  5. Indian Womanhood: Some Psychological Concepts*

    OpenAIRE

    Dhanalakshmi De Sousa; Avinash De Sousa

    2015-01-01

    Indian womanhood today is at crossroads. The present paper discusses the status of Indian womanhood and its psychological underpinnings. It discusses how Indian women have suffered at the hands of their families and society leaving no path but to succumb to psychiatric illness. The role of mental health professionals and family members in supporting and promoting growth and development of the Indian woman is outlined.

  6. Indian Womanhood: Some Psychological Concepts

    Directory of Open Access Journals (Sweden)

    Dhanalakshmi De Sousa

    2015-01-01

    Full Text Available Indian womanhood today is at crossroads. The present paper discusses the status of Indian womanhood and its psychological underpinnings. It discusses how Indian women have suffered at the hands of their families and society leaving no path but to succumb to psychiatric illness. The role of mental health professionals and family members in supporting and promoting growth and development of the Indian woman is outlined.

  7. Indian womanhood: some psychological concepts.

    Science.gov (United States)

    De Sousa, Dhanalakshmi; De Sousa, Avinash

    2015-01-01

    Indian womanhood today is at crossroads. The present paper discusses the status of Indian womanhood and its psychological underpinnings. It discusses how Indian women have suffered at the hands of their families and society leaving no path but to succumb to psychiatric illness. The role of mental health professionals and family members in supporting and promoting growth and development of the Indian woman is outlined. PMID:25838719

  8. Global Trade and Indian Politics

    DEFF Research Database (Denmark)

    Lubinski, Christina

    2015-01-01

    This article analyzes the German dye business in India before 1947 as an example of expanding German-Indian commercial relationships. German dye manufacturers showed great interest in India's economic potential in the absence of discriminatory tariffs, while Indian elites were interested in non...... the political boundaries of formal empire and offers an alternative perspective on Indian business history, which reveals more competition between multinationals of different origins and more strategic choices available to Indians....

  9. Working Women: Indian Perspective

    OpenAIRE

    Dharmendra MEHTA; Naveen K. MEHTA; MEHTA Rajesh Kumar

    2014-01-01

    In India, due to unprecedented rise in the cost of living, ris-ing prices of commodities, growing expenses on children ed-ucation, huge rate of unemployment, and increasing cost of housing properties compel every Indian family to explore all the possible ways and means to increase the household income. It is also witnessed that after globalization Indian women are able to get more jobs but the work they get is more casual in nature or is the one that men do not prefer to do or is left by them...

  10. Analysis of Uranium and Thorium in Radioactive Wastes from Nuclear Fuel Cycle Process

    International Nuclear Information System (INIS)

    The assessment of analysis method for uranium and thorium in radioactive wastes generated from nuclear fuel cycle process have been carried out. The uranium and thorium analysis methods in the assessment are consist of Titrimetry, UV-VIS Spectrophotometry, Fluorimetry, HPLC, Polarography, Emission Spectrograph, XRF, AAS, Alpha Spectrometry and Mass Spectrometry methods. From the assessment can be concluded that the analysis methods of uranium and thorium content in radioactive waste for low concentration level using UV-VIS Spectrometry is better than Titrimetry method. While for very low concentration level in part per billion (ppb) can be used by Neutron Activation Analysis (NAA), Alpha Spectrometry and Mass Spectrometry. Laser Fluorimetry is the best method of uranium analysis for very low concentration level. Alpha Spectrometry and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) methods for isotopic analysis are favourable in the precision and accuracy aspects. Comparison of the ICP-MS and Alpha Spectrometry methods shows that the both of methods have capability to determining of uranium and thorium isotopes content in the waste samples with results comparable very well, but the time of its analysis using ICP-MS method is faster than the Alpha Spectrometry, and also the cost of analysis for ICP-MS method is cheaper. NAA method can also be used to analyze the uranium and thorium isotopes, but this method needs the reactor facility and also the time of its analysis is very long. (author)

  11. Separation and purification of uranium product from thorium in thorex process by precipitation technique

    International Nuclear Information System (INIS)

    A sequential precipitation technique is reported for the separation of uranium and thorium present in the uranium product stream of a single cycle 5 per cent TBP Thorex Process. It involves the precipitation of thorium as oxalate in 1M HNO3 medium at 60-70degC and after filtration, precipitation of uranium as ammonium diuranate at 80-90degC from the oxalate supernatant. This technique has several advantages over the ion-exchange process normally used for treating these products. In order to meet the varying feed conditions, this method has been tested for feeds containing 10 g/1 uranium and 1-50 g/1 thorium in 1-6M HNO3. Various parameters like feed acidities, uranium and thorium concentrations, excess oxalic acid concentrations in the oxalate supernatant, precipitation temperatures, precipitate wash volumes etc. have been optimised to obtain more than 99 per cent recovery of thorium and uranium as their oxides with less than 50 ppm uranium losses to ammonium diuranate filtrate. The distribution patterns of different fission products and stainless steel corrosion products during various steps of this procedure have also been studied. For simulating the actual Thorex plant scale operation, experiments have been conducted with 25g and 100g lots of uranium per batch. (author). 6 tabs., 8 figs., 22 refs

  12. A Canadian perspective on progress in thorium R and D: towards sustainability

    International Nuclear Information System (INIS)

    Currently heavy water reactors in Canada and internationally typically operate on a once-through nuclear fuel cycle using mainly natural uranium fuel. Future nuclear power program decisions will be increasingly based on strategic considerations involving the complete nuclear fuel cycle, including requirements related to supply assurances, resource utilization, proliferation resistance and radioactive waste disposal. Heavy water technology is uniquely suited to respond to future needs because of its inherent technical characteristics and associated fuel cycle flexibility. Given its widespread abundance, thorium is expected to play a significant role as nations move towards implementation of advanced fuel cycles. Canadian Nuclear Laboratories (which evolved from Atomic Energy of Canada Limited) has been investigating thorium fuelled reactor concepts and developing thoria (thorium dioxide) fuel technology for more than 55 years, which complements international experience in the development of thorium-based fuel cycles. Although there is a strong foundation based on past experience, gaps exist in the science and technology required to implement the use of thorium-based fuels on an industrial scale. Recent progress and some aspects of the necessary evolution of the technology are outlined in this paper

  13. Thorium distribution on the lunar surface observed by Chang'E-2 gamma-ray spectrometer

    Science.gov (United States)

    Wang, Xianmin; Zhang, Xubing; Wu, Ke

    2016-07-01

    The thorium distribution on the lunar surface is critical for understanding the lunar evolution. This work reports a global map of the thorium distribution on the lunar surface observed by Chang'E-2 gamma-ray spectrometer (GRS). Our work exhibits an interesting symmetrical structure of thorium distribution along the two sides of the belt of Th hot spots. Some potential positions of KREEP volcanism are suggested, which are the Fra Mauro region, Montes Carpatus, Aristarchus Plateau and the adjacent regions of Copernicus Crater. Based on the lunar map of thorium distribution, we draw some conclusions on two critical links of lunar evolution: (1) the thorium abundance within the lunar crust and mantle, in the last stage of Lunar Magma Ocean (LMO) crystallization, may have a positive correlation with the depth in the crust, reaches a peak when coming through the transitional zone between the crust and mantle, and decreases sharply toward the inside of the mantle; thus, the Th-enhanced materials originated from the lower crust and the layer between the crust and mantle, (2) in PKT, KREEP volcanism might be the primary mechanism of Th-elevated components to the lunar surface, whereas the Imbrium impact acted as a relatively minor role.

  14. Characteristics of Modular Fast Reactor SVBR-100 Using Thorium-Uranium (233) Fuel

    International Nuclear Information System (INIS)

    Natural reserves of thorium are three times as much as those of uranium. For that reason, thorium is a very promising raw material for manufacturing an artificial fissionable isotope of uranium-233 that is formed when neutrons are absorbed by thorium. Many countries are investigating characteristics of reactors using thorium-uranium (233) fuel. First, breeding ratio (BR) is of interest because only when BR = 1, the reactor can operate in a closed fuel cycle in a mode of fuel self-providing without makeup by other fissionable isotopes. The report presents the results of calculations of neutron-physical and thermal-hydraulic characteristics of SVBR-100 - lead-bismuth cooled small power modular fast reactor using thorium-uranium (233) fuel. Reactor SVBR-100 has specific properties of inherent self-protection and passive safety. The NPP modular power-units, which power equals to a value divisible by 100 MWe, can be constructed on the basis of reactor modules SVBR-100. (author)

  15. Biomedical and environmental aspects of the thorium fuel cycle: a selected, annotated bibliography

    International Nuclear Information System (INIS)

    This bibliography was compiled to assist in the evaluation of the health and environmental consequences of high specific activity thorium and related nuclides which could be released to the environment by activities related to the Thorium Fuel Cycle. The general scope covers studies regarding potential releases, environmental transport, metabolism, dosimetry, dose assessment, and overall risk assessment for radionuclides specific to the NASAP project. This publication of 740 abstracted references highlights the biological and medical aspects of thorium 228 and thorium 232 in man and animals. Similar studies on related nuclides such as radium 224, radium 226, radium 228, and thorium 230 are also emphasized. Additional categories relevant to these radionuclides are included as follows: chemical analysis; ecological aspects; energy; geological aspects; instrumentation; legal and political aspects; monitoring, measurement and analysis; physical aspects; production; radiation safety and control; and waste disposal and management. Environmental assessment and sources categories were used for entries which contain a multiple use of categories. Leading authors appear alphabetically within each category. Indexes are provided for : author(s), geographic location, keywords, title, and publication description. The bibliography contains literature dating from December 1925 to February 1978

  16. The structural and genetic position uranium-thorium mineralization of Azov megablock

    Directory of Open Access Journals (Sweden)

    Katalenets A.I.

    2014-12-01

    Full Text Available The genetic characteristics of development and placement uranium-thorium mineralization and distribution of their concentrations in Azov megablock areas are examined. The main structures of Azov megablock areas controlling of distribution of metasomatic types and ore occurrence related with them are set. Preliminary basis for the allocation of boundaries and areas of ore districts is created. Considered theoretical and practical problem associated with the establishment of regional characteristics, genetic types of mineralization, its structural and temporary accommodation, the development of search criteria and characteristics of mineralization, the release of potentially mineralized areas and study areas of prospecting for Azov megablock of Ukrainian shield. The research is based on data on the geological structure of the PM, and the structural control of the placement lithochemical uranium and thorium anomalies occurrences and deposits, typomorphic properties of minerals, the phase distribution of uranium, thorium. Distribution of uranium and thorium mineralization in areas considered structure is: own minerals, isomorphic impurity in minerals associated with them, or turn on the first to the last. Uranium and thorium PM mineralization is characterized by a genetic (paragenetic involving mineral associations exogenous and metasomatic rocks.

  17. Biomonitoring of environmental pollution by thorium and uranium in selected regions of the Republic of Kazakhstan.

    Science.gov (United States)

    Zoriy, P; Ostapczuk, P; Dederichs, H; Höbig, J; Lennartz, R; Zoriy, M

    2010-05-01

    Two former uranium mines and a uranium reprocessing factory in the city of Aktau, Kazakhstan, may represent a risk of contaminating the surrounding areas by uranium and its daughter elements. One of the possible fingerprinting tools for studying the environmental contamination is using plant samples, collected in the surroundings of this city in 2007 and 2008. The distribution pattern of environmental pollution by uranium and thorium was evaluated by determining the thorium and uranium concentrations in plant samples (Artemisia austriaca) from the city of Aktau and comparing these results with those obtained for the same species of plants from an unpolluted area (town of Kurchatov). The determination of the uranium and thorium concentrations in different parts of A. austriaca plants collected from the analyzed areas demonstrated that the main contamination of the flora in areas surrounding the city of Aktau was due to dust transported by the wind from the uranium mines. The results obtained demonstrate that all the areas surrounding Aktau have a higher pollution level due to thorium and uranium than the control area (Kurchatov). A few "hot points" with high concentrations of uranium and thorium were found near the uranium reprocessing factory and the uranium mines.

  18. The Spectrum of Thorium from 250 nm to 5500 nm: Ritz Wavelengths and Optimized Energy Levels

    CERN Document Server

    Redman, Stephen L; Sansonetti, Craig J

    2013-01-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists (Giacchetti et al. 1974; Zalubas & Corliss 1974; Zalubas 1976; Palmer & Engleman 1983; Engleman et al. 2003; Lovis & Pepe 2007; Kerber et al. 2008) to re-optimize the energy levels of neutral, singly-, and doubly-ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19679 thorium lines between 250 nm and 5500 nm (40000 1/cm to 1800 1/cm). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer & Engleman (1983) and typographical errors and incorrect classifications in Kerber et al. (2008). We also found a la...

  19. Review of R and D of thorium molten-salt reactor

    International Nuclear Information System (INIS)

    Nuclear power will be used continuously as low-carbon energy for a sustainable society. On the other hand, prime attention is inclined to thorium molten-salt reactor (MSR) in recent years due to necessity for radioactive waste disposal, nuclear non-proliferation ('world without nuclear weapon') and higher safety of nuclear power. Thorium MSR is a type of liquid-fueled reactor utilizing thorium as fertile with some fissile materials contained in molten-salt. Research and development (R and D) of MSR started in the 1950s at Oak-Ridge National Laboratory (ORNL) for aircraft reactors. R and D activities were later extended to develop civilian power reactors using thorium, a concept which was completed in the 1970s. Nonetheless, technical problems still remained, such as temperature reactivity coefficient, material corrosion, and tritium permeation at heat exchanger. Since the 1980s several R and D activities to circumvent these problems have been done inside and outside ORNL. The problems relating to thorium MSR and recent R and D activities will be introduced in this paper. (author)

  20. Potential of Melastoma malabathricum as bio-accumulator for uranium and thorium from soil

    International Nuclear Information System (INIS)

    Uranium and Thorium are naturally occuring radionuclides. However, due to anthropogenic activities in some locations their concentrations in the soils could be elevated. This study explores the potential of Melastoma malabathricum (locally known as ‘pokok senduduk’) as bio-accumulator of uranium and thorium from soils of three different study areas, namely former tin mining, industrial and residential/commercial areas in Peninsular Malaysia. The study found elevated concentrations of uranium and thorium in former tin mining soils as compared to natural abundance. However in industral and residential/commercial areas the concentrations are within the range of natural abundance. In terms of transfer factor (TF), in ex-mining areas TF > 1 for uranium in the leaf, stem and roots, indicating accumulation of uranium from soil. However for thorium TF < 1, indicating the occurence of transfer from soil to root, stem and leaf, but no accumulation. For other areas only transfer of uranium and thorium were observed. The results indicated the potential of Melastoma malabathricum to be used as bio-accumulatior of uranium, especially in areas of elevated concentration

  1. Thorium-Based Fuel Cycles in the Modular High Temperature Reactor

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong; YANG Yongwei; JING Xingqing; XU Yunlin

    2006-01-01

    Large stockpiles of civil-grade as well as weapons-grade plutonium have been accumulated in the world from nuclear power or other programs of different countries. One alternative for the management of the plutonium is to incinerate it in the high temperature reactor (HTR). The thorium-based fuel cycle was studied in the modular HTR to reduce weapons-grade plutonium stockpiles, while producing no additional plutonium or other transuranic elements. Three thorium-uranium fuel cycles were also investigated. The thorium absorption cross sections of the resolved and unresolved resonances were generated using the ZUT-DGL code based on existing resonance data. The equilibrium core of the modular HTR was calculated and analyzed by means of the code VSOP'94. The results show that the modular HTR can incinerate most of the initially loaded plutonium amounting to about 95.3% net 239Pu for weapons-grade plutonium and can effectively utilize the uranium and thorium in the thorium-uranium fuel cycles.

  2. Biomedical and environmental aspects of the thorium fuel cycle: a selected, annotated bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Faust, R.A.; Fore, C.S.; Cone, M.V.; Meyer, H.R.; Till, J.E.

    1979-07-01

    This bibliography was compiled to assist in the evaluation of the health and environmental consequences of high specific activity thorium and related nuclides which could be released to the environment by activities related to the Thorium Fuel Cycle. The general scope covers studies regarding potential releases, environmental transport, metabolism, dosimetry, dose assessment, and overall risk assessment for radionuclides specific to the NASAP project. This publication of 740 abstracted references highlights the biological and medical aspects of thorium 228 and thorium 232 in man and animals. Similar studies on related nuclides such as radium 224, radium 226, radium 228, and thorium 230 are also emphasized. Additional categories relevant to these radionuclides are included as follows: chemical analysis; ecological aspects; energy; geological aspects; instrumentation; legal and political aspects; monitoring, measurement and analysis; physical aspects; production; radiation safety and control; and waste disposal and management. Environmental assessment and sources categories were used for entries which contain a multiple use of categories. Leading authors appear alphabetically within each category. Indexes are provided for : author(s), geographic location, keywords, title, and publication description. The bibliography contains literature dating from December 1925 to February 1978.

  3. Floatation-spectrophotometric Determination of Thorium, Using Complex Formation with Eriochrome Cyanine R

    Science.gov (United States)

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Khezeli, Tahereh; Badkiu, Nadie

    2011-01-01

    A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6–230 ng mL−1 of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL−1. The relative standard deviations for determination of 150 and 30 ng ml−1 of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples. PMID:21340019

  4. Title IV: Improving Indian Education.

    Science.gov (United States)

    Barker, Kipp A.

    The Indian Education Act of 1972, Title IV, has improved Native American education by emphasizing Native American control; it comes after 400 years of Euro-American involvement in Indian education during which assimilation was the primary goal. In 1568 Jesuit priests began "civilizing" and Christianizing the "savage" Indians; in 1794 the first…

  5. Alcohol and American Indian Students.

    Science.gov (United States)

    Boyce, George A.

    The growing problem of teenage drinking and alcoholism in the United States, especially among Indian segments of society, increases the necessity for adequate education concerning alcoholism. This document is prepared for the Bureau of Indian Affairs (BIA) schools to acquaint Indian students with social concepts of alcohol outside their cultural…

  6. 76 FR 49505 - Indian Gaming

    Science.gov (United States)

    2011-08-10

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... Compact between the State of California and the Habematolel Pomo of Upper Lake taking effect. DATES: Effective Date: August 10, 2011. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of...

  7. 77 FR 5566 - Indian Gaming

    Science.gov (United States)

    2012-02-03

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of... Compact between the State of California and the Pinoleville Pomo Nation Taking Effect. DATES: Effective Date: February 3, 2012. FOR FURTHER INFORMATION CONTACT: Paula L. Hart, Director, Office of...

  8. 78 FR 54670 - Indian Gaming

    Science.gov (United States)

    2013-09-05

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of extension of Tribal--State Class III Gaming Compact. SUMMARY: This publishes notice of the Extension of the Class III gaming compact between the Yankton Sioux Tribe and the State of South Dakota. DATES:...

  9. 78 FR 17428 - Indian Gaming

    Science.gov (United States)

    2013-03-21

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes the approval of the Class III Tribal- State Gaming Compact between the Pyramid Lake Paiute Tribe and the State of...

  10. 77 FR 30550 - Indian Gaming

    Science.gov (United States)

    2012-05-23

    ... of Approval in the Federal Register on February 23, 2010 (47 FR 44678). This agreement allows for the... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal--State Class III Gaming Compact. SUMMARY: This notice publishes approval by the...

  11. 78 FR 62650 - Indian Gaming

    Science.gov (United States)

    2013-10-22

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of extension of Tribal-State Class III Gaming Compact. SUMMARY: This publishes notice of the extension of the Class III gaming compact between the Rosebud Sioux Tribe and the State of South Dakota. DATES:...

  12. 78 FR 78377 - Indian Gaming

    Science.gov (United States)

    2013-12-26

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ] ACTION: Notice of extension of Tribal-State Class III Gaming Compact. SUMMARY: This publishes notice of the extension of the Class III gaming compact between the Yankton Sioux Tribe and the State of South Dakota. DATES:...

  13. 78 FR 17427 - Indian Gaming

    Science.gov (United States)

    2013-03-21

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Compact. SUMMARY: This notice publishes approval of the agreement between the Northern Cheyenne Tribe and the State of Montana concerning Class III Gaming (Compact)....

  14. 78 FR 33435 - Indian Gaming

    Science.gov (United States)

    2013-06-04

    ... Bureau of Indian Affairs Indian Gaming AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice of Approved Tribal-State Class III Gaming Amendments. SUMMARY: This notice publishes approval of an Agreement to Amend the Class III Tribal-State Gaming Compact between the Salt River Pima- Maricopa...

  15. Resisting the Script of Indian Education: Zitkala Sa and the Carlisle Indian School.

    Science.gov (United States)

    Enoch, Jessica

    2002-01-01

    Offers a "definition" of Zitkala Sa as an Indian teacher who, at the turn of the 20th century, challenged and countered educational norms that silenced Indian voices and erased Indian culture. Examines her autobiographical essays, "Impressions of an Indian Childhood,""The School Days of an Indian Girl," and "An Indian Teacher among Indians," in…

  16. 10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

    Science.gov (United States)

    2010-01-01

    ... long-term care of uranium or thorium byproduct materials disposal sites. (a) A general license is... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill... this general license is to ensure that uranium and thorium mill tailings disposal sites will be...

  17. CALIFORNIA INDIAN EDUCATION, REPORT OF THE FIRST ALL-INDIAN STATEWIDE CONFERENCE ON CALIFORNIA INDIAN EDUCATION.

    Science.gov (United States)

    FORBES, JACK D.

    A CONFERENCE ON CALIFORNIA INDIAN EDUCATION WAS HELD IN MARCH, 1967, AT STANISLAUS STATE COLLEGE. THE CONFERENCE PARTICIPANTS INCLUDE ADMINISTRATORS AND TEACHERS FROM REPRESENTATIVE SCHOOLS WITH A HIGH PROPORTION OF INDIAN STUDENTS IN CALIFORNIA, ANTHROPOLOGISTS AND SOCIAL SCIENTISTS FROM VARIOUS COLLEGES, AND INDIANS FROM REPRESENTATIVE AREAS…

  18. Indian School Days.

    Science.gov (United States)

    Johnston, Basil H.

    This autobiography relates the experiences of a young Ojibway boy who was taken from his family in 1939 at age 10 and placed in a Jesuit boarding school in northern Ontario, Canada. St. Peter Claver (later Garnier) or "Spanish," as the Indian school was known, was home to approximately 135 boys. Most of the students, who ranged in age from 4 to…

  19. Indians of North Carolina.

    Science.gov (United States)

    Bureau of Indian Affairs (Dept. of Interior), Washington, DC.

    Published by the U.S. Department of the Interior, this brief booklet on the historical development of the Cherokee Nation emphasizes the Tribe's relationship with the Bureau of Indian Affairs and its improved economy. Citing tourism as the major tribal industry, tribal enterprises are named and described (a 61 unit motor court in existence since…

  20. Radiocarbon and Indian archaeology

    International Nuclear Information System (INIS)

    The increasing use of radiocarbon (C14) dating techniques in Indian archaeology has been described in detail. Work done in Microlithic cultures, Neolithic period, Indus civilization and Iron age cultures have been reported. C14 dates of various archaeological sites are listed. (K.B.)

  1. American Indian Authors.

    Science.gov (United States)

    Momaday, Natachee Scott

    Twenty-six selections by 15 contemporary American Indian authors are given in this book. The selections--legends, ceremonial chants and prayers, poems, and stories--are accompanied by topics for discussion. Some of the selections deal with the supernatural, and some tell an actual story about the author. Pictures and short biographies of each…

  2. Caregiving in Indian Country

    Centers for Disease Control (CDC) Podcasts

    2009-12-23

    This podcast discusses the role of caregivers in Indian County and the importance of protecting their health. It is primarily targeted to public health and aging services professionals.  Created: 12/23/2009 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 12/23/2009.

  3. The Urban Indian.

    Science.gov (United States)

    Hanson, Winona DuBray

    The document presents six articles that provide a glimpse of the uniqueness of American Indian cultural conflict, focusing on aspects of the culture which warrant special attention. Since there are over 100 tribes, an effort was made to enumerate commonalities amongst the tribal cultures in looking at issues raised in the urban areas throughout…

  4. American Indian Recipes.

    Science.gov (United States)

    Gurnoe, Katherine J.; Skjervold, Christian, Ed.

    Presenting some 60 to 70 Native American recipes, this document includes a brief introduction and a suggested reading list (15 citations related to American Indian foods). The introduction identifies five regional Native American cuisines as follows: in the Southwest, peppers and beans were made into chili, soups, guacamole, and barbecue sauces by…

  5. Indian Astronomy: History of

    Science.gov (United States)

    Mercier, R.; Murdin, P.

    2002-01-01

    From the time of A macronryabhat under dota (ca AD 500) there appeared in India a series of Sanskrit treatises on astronomy. Written always in verse, and normally accompanied by prose commentaries, these served to create an Indian tradition of mathematical astronomy which continued into the 18th century. There are as well texts from earlier centuries, grouped under the name Jyotishaveda macronn d...

  6. Thermodynamic studies of thorium carbide fuel preparation and fuel/clad compatibility

    International Nuclear Information System (INIS)

    The carbothermic reduction of thorium and uranium-thorium dioxide to monocarbide has been assessed. Equilibrium calculations have yielded Th-C-O and U-Th-C-O phase equilibria and CO pressures generated during reduction. The CO pressures were found to be at least five orders of magnitude greater than any of the other 15 gaseous species considered. This confirms that the monocarbide can successfully be prepared by carbothermic reduction. The chemical compatibility of thorium carbides with the Cr-Fe-Ni content of clad alloys has been thermodynamically evaluated. Solid solutions of 5> and 5> and of 7C3> and 7C3> were the principal reaction products. The Cr-Fe-Ni content of 316 stainless steel showed much less reaction product than that of any of the other six alloys considered. (author)

  7. Conceptual design study of small long-life PWR based on thorium cycle fuel

    Energy Technology Data Exchange (ETDEWEB)

    Subkhi, M. Nurul [Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Science, Bandung Institute of Technology (Ganesha 10 Bandung, Indonesia) and Physics Dept., Faculty of Science and Technology, State Islamic University of Sunan Gunung (Indonesia); Su' ud, Zaki; Waris, Abdul; Permana, Sidik [Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Science, Bandung Institute of Technology (Ganesha 10 Bandung) (Indonesia)

    2014-09-30

    A neutronic performance of small long-life Pressurized Water Reactor (PWR) using thorium cycle based fuel has been investigated. Thorium cycle which has higher conversion ratio in thermal region compared to uranium cycle produce some significant of {sup 233}U during burn up time. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.3, while the multi-energy-group diffusion calculations were optimized in whole core cylindrical two-dimension R-Z geometry by SRAC-CITATION. this study would be introduced thorium nitride fuel system which ZIRLO is the cladding material. The optimization of 350 MWt small long life PWR result small excess reactivity and reduced power peaking during its operation.

  8. Application of hollow cylindrical wheat stem for electromembrane extraction of thorium in water samples

    DEFF Research Database (Denmark)

    Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Barkhordar, Afsaneh;

    2015-01-01

    In this study, wheat stem was used for electromembrane extraction (EME) for the first time. The EME technique involved the use of a wheat stem whose channel was filled with 3 M HCl, immersed in 10 mL of an aqueous sample solution. Thorium migrated from aqueous samples, through a thin layer of 1......-octanol and 5%v/v Di-(2-ethylhexyl) phosphate (DEHP) immobilized in the pores of a porous stem, and into an acceptor phase solution present inside the lumen of the stem. The pH of donor and acceptor phases, extraction time, voltage, and stirring speed were optimized. At the optimum conditions......, an enrichment factor of 50 and a limit of detection of 0.29 ng mL1 was obtained for thorium. The developed procedure was then applied to the extraction and determination of thorium in water samples and in reference material....

  9. Once-through thorium fuel cycle evaluation for TVA's Browns Ferry-3 Boiling Water Reactor

    International Nuclear Information System (INIS)

    This report documents benchmark evaluations to test thorium lattice predictive methods and neutron cross sections against available data and summarizes specific evaluations of the once-through thorium cycle when applied to the Browns Ferry-3 BWR. It was concluded that appreciable uncertainties in thorium cycle nuclear data cloud the ability to reliably predict the fuel cycle performance and that power reactor irradiations of ThO2 rods in BWRs are desirable to resolve uncertainties. Benchmark evaluations indicated that the ENDF/B-IV data used in the evaluations should cause an underprediction of U-233/ThO2 fuel reactivity, and, therefore, the results of the preliminary evaluations completed under the program should be conservative

  10. Long-term health effects of thorium compounds on exposed workers: the complete blood count

    International Nuclear Information System (INIS)

    Two hundred seventy-three men exposed to thorium and other rare earths between 1940 and 1973 at a plant which refined monazite sand were studied at Argonne National Laboratory from 1976 to 1980. In vivo measurements of body burden were made by counting gamma rays emitted by daughter products of retained thorium and by measuring exhaled thoron. Health status was ascertained through questionnaire, physical examination, and clinical laboratory tests. Measured body burden was found to be higher in those with a history of longer exposure. All parameters of the complete blood count were examined for evidence of an effect due to thorium. Comparisons of high and low body burden groups showed that only age and cigarette smoking had an effect on complete blood count parameters

  11. Stabilization of Th 3+ ions into mixed-valence thorium fluoride

    Science.gov (United States)

    Dubois, Marc; Dieudonné, Belto; Mesbah, Adel; Bonnet, Pierre; El-Ghozzi, Malika; Renaudin, Guillaume; Avignant, Daniel

    2011-01-01

    The unusual oxidation state +3 of the thorium has been stabilized into a lithium containing non-stoichiometric mixed-valence (III/IV) thorium fluorinated phase with formula Li 2+ xTh 12F 50 (0afore mentioned single phase may be considered as an insertion compound. The Li + insertion is accompanied by the simultaneous reduction of a part of the Th 4+ ions, resulting in a mixed-valence III/IV thorium fluoride. The electrochemical insertion of Li + ions into the open channels of the host matrix has been carried out at 60 °C, using an alkylcarbonate PC-LiClO 4 1 M electrolyte. The Li + and Th 3+ contents, both in the starting composition and the Li + inserted ones, were investigated by high resolution solid state 7Li NMR and EPR, respectively.

  12. The measurement of thorium lung burden and its preventive function for pneumoconiosis

    International Nuclear Information System (INIS)

    Objective: To discuss the measurement of thorium lung burden and its preventive function for pneumoconiosis. Methods: Exhaled thoron activity was measured by a negative high voltage electrostatic collection and measurement system. Pneumoconiosis were diagnosed by double-blinded method. Results: 50 out of 275 miners suffered from 0+ pneumoconiosis. The result showed that if one's thorium lung burden reached 756 mg, the pneumoconiosis of stage 0+ would be induced. Meanwhile the result of 7 year-follow-up study on a miner suffered from pneumoconiosis stage I indicated that 44% of the residual lung burden was clearing with a half-time of 112 days. However, the half-time of the second phase was ∼ 7000 years. Conclusion: The measurement of thorium lung burden could help the prevention from pneumoconiosis. (authors)

  13. Development of an in vitro bioassay method to determine the intake q natural thorium

    International Nuclear Information System (INIS)

    A simple and economic method for analytical determination of the Th-232 concentration in excreta samples (urine and feces) was developed, using Th-229 as a tracer. Solvent extraction followed by alpha spectrometry was employed. The minimum activity detectable for urine samples was (0,36 ± 0,05) mBq/dm3 and for fecal samples (0,52 ± 0,12) mBq/dm3. Two groups of persons were analyzed. The first one, A, contituted by persons non ocupationally exposed and the second one, B, by workers ocupationally exposed. The results of thorium concentration in excreta samples from group A were compared with the daily excretion due to alimentary diet of thorium and the results obtained from the second group were compared with the limits of excretion derived from the annual limits of intake recommended by the ICRP. All the samples analyzed showed thorium concentration levels bellow the limits recommended by the ICRP. (author)

  14. Simulation calculation of 232U productions in thorium-uranium transform process based on thermal reactor

    International Nuclear Information System (INIS)

    The decay products of 232U produced in the thorium-uranium fuel cycle emit high energy γ-rays. This affects the fuel cycle greatly. In this paper, the 232U productions in thermal reactor using thorium fuel are analyzed by ORIGEN2, SCALE5 and the code based on the Bateman method. Under normal situation, 232U is mainly produced by 232Th (n, 2n) reaction chain, and more quantity of 230Th can be transformed into 232U while the neutron spectrum is softer. The burnup calculation of CANDU reactor and PWR assembly indicates that the 232U in uranium increase with the burnup, and 230Th in fresh thorium has linear correlation with 232U/Utotal or 232U/233U at discharge burnup. (authors)

  15. The levels of uranium and thorium in soils and vegetables from Cornwall and Sutherland

    International Nuclear Information System (INIS)

    Soils from Sutherland and Cornwall may contain high natural levels of uranium and thorium. Samples of soil and vegetables were taken from agricultural land in these regions, and the levels of uranium and thorium were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Delayed Neutron Activation Analysis (DNAA). Mean levels of uranium and thorium in the soils were, respectively, 3.5 times and 1.5 times greater than the British average. Uptake factors were calculated from these data and found to be of the order 10-4 to 10-3 which is in agreement with published literature. The Tessier extraction scheme was applied to some of the soils and the low levels present in the ''exchangeables'' fraction are consistent with the uptake factors. (author)

  16. Updated determination of particulate and dissolved thorium-234

    Science.gov (United States)

    Fleer, Alan P.

    The determination of particulate and dissolved 234Th is similar to the procedure of Anderson and Fleer [1982]. Samples are collected using 30 L Niskin bottles with Teflon- or epoxy-coated internal springs. On deck, the sample is pumped with a delrin impeller pump through a 0.45 μm pore size 147-mm diameter Millipore filter and into a pre-rinsed 6 gallon plastic cubitainer held in a plastic milk crate. An in-line plastic water meter records volumes in gallons. The particulate sample filter is folded twice and stored in a polyethylene sample bag. To the ˜20 L filtered sample is added: 30 mL reagent grade 16 N HNO3; 500 mL 230Th tracer of ˜30 dpm mL-l and 5 mL 50 mg mL-l iron carrier previously cleaned by extraction into isopropyl ether from an 8 M HCl solution and back-extracted into 0.1 M HCl. The acidified sample is allowed to equilibrate for from one day to a maximum of several days. The sample is weighed on a Heathkit digital scale and the pH is adjusted to approximately 8 with about 40 mL 10 M NH4OH to precipitate iron hydroxide, which carries the thorium and uranium from the solution. The precipitate is allowed to settle for 12 to 24 hours. The supernate is drawn off, and the precipitate is spun down in a centrifuge tube to about an 8 mL volume. The precipitate is resuspended in distilled water and spun down again, then dissolved in three times its volume with 12 N HCl to make a 9 N HCl solution. A 1.5 cm×12 cm ion exchange column is filled with AG1×8 100-200 mesh resin and conditioned with 9 N HCl. The sample solution is run slowly through.

  17. Preliminary safety analysis of a thorium high-conversion pebble bed reactor

    International Nuclear Information System (INIS)

    An inherently safe thorium High-Conversion Pebble Bed Reactor would combine the inherent safety characteristics of the Pebble Bed Reactor with the favourable waste characteristics and resource availability of the thorium fuel cycle. Previous work by the authors showed that high conversion ratio's can be achieved within a thorium Pebble Bed Reactor (PBR) at a practical operating regime. The thorium PBR core design consists of a cylindrical core with a central driver zone surrounded by a breeder zone. The breeder pebbles have a 30 g heavy metal (HM) loading to enhance conversion of Th-232 into U-233, while the driver pebbles (10 w% U-233) contain a lower metal loading to enhance fission. In previous studies, thorium PBR designs were presented for three core diameters, using a 7.5 g heavy metal (HM) loading for the driver pebbles. The current paper investigates the safety of these thorium PBR designs in terms of reactivity coefficients and possible reactivity insertion due to water ingress. Early results indicated that the values of the reactivity coefficients for the three designs with 7.5 g HM loading per driver pebble were rather small and the possible reactivity insertion due to water ingress was very large. Therefore, also a lower HM loading per driver pebble (4 g) was investigated to reduce the impact of water ingress, since the core becomes less under-moderated. For the three core diameters investigated, it is shown that reducing the metal loading in the driver pebbles to 4 g is indeed advantageous in terms of safety, water ingress leads to a smaller reactivity increase but also the reactivity coefficients become stronger negative. Secondly, the breeding performance of the cores with a 4 g driver pebble HM loading improves. On the downside, the driver pebble residence times become shorter, which could increase fuel reprocessing costs. Fuel pebbles would have to be recycled at an increased rate, which might be more challenging from a practical perspective

  18. Environmental impact of radioactive releases from recycle of thorium-based fuel using current containment technology

    International Nuclear Information System (INIS)

    The analysis of thorium mining and milling suggests that the resulting doses should be similar to those from uranium operations. An absolute comparison cannot be made at this time, however, due to differences in some assumptions utilized by the various investigators and the lack in some cases of site-specific meteorology and population data at thorium resource sites in the western United States. A distinct difference resulting from the short half-life of 220Rn (T/sub 1/2/ = 55.6 s) in the thorium decay chain compared to that for 222Rn (T/sub 1/2/ = 3.82 d) in uranium decay was noted for emissions following mill shutdown. This effect is to make potential releases following thorium mill shutdown of lesser consequence than in the uranium case. Thorium tailings activity would also decrease relatively rapidly due to the comparatively short half-life (T/sub 1/2 = 5.75 y) of 228Ra. Doses due to airborne releases from thorium-uranium carbide fuel refabrication are significantly less than that due to fuel reprocessing. Tritium is the principal contributor to reprocessing plant doses while carbon-14, 131Cs, and 232U account for most of the remaining dose. A tenfold increase in reprocessing plant CF for tritium reduces both individual and population doses by about 60%. For refabrication operations, a near linear dependence upon dose with 232U content of the fuel was calculated between concentrations of 10 ppM and 5000 ppM. Comparison of (Th, U)C and (U, Pu)C showed little difference in dose commitment, but the presence of 232U in the (Th, U) fuel causes a notable increase in the refabrication plant dose over that previously calculated for (U, Pu) type fuels

  19. Core Design and Deployment Strategy of Heavy Water Cooled Sustainable Thorium Reactor

    Directory of Open Access Journals (Sweden)

    Naoyuki Takaki

    2012-08-01

    Full Text Available Our previous studies on water cooled thorium breeder reactor based on matured pressurized water reactor (PWR plant technology concluded that reduced moderated core by arranging fuel pins in a triangular tight lattice array and using heavy water as coolant is appropriate for achieving better breeding performance and higher burn-up simultaneously [1–6]. One optimum core that produces 3.5 GW thermal energy using Th-233U oxide fuel shows a breeding ratio of 1.07 and averaged burn-up of about 80 GWd/t with long cycle length of 1300 days. The moderator to fuel volume ratio is 0.6 and required enrichment of 233U for the fresh fuel is about 7%. The coolant reactivity coefficient is negative during all cycles despite it being a large scale breeder reactor. In order to introduce this sustainable thorium reactor, three-step deployment scenario, with intermediate transition phase between current light water reactor (LWR phase and future sustainer phase, is proposed. Both in transition phase and sustainer phase, almost the same core design can be applicable only by changing fissile materials mixed with thorium from plutonium to 233U with slight modification in the fuel assembly design. Assuming total capacity of 60 GWe in current LWR phase and reprocessing capacity of 800 ton/y with further extensions to 1600 ton/y, all LWRs will be replaced by heavy water cooled thorium reactors within about one century then thorium reactors will be kept operational owing to its potential to sustain fissile fuels while reprocessing all spent fuels until exhaustion of massive thorium resource.

  20. Gel and xerogel of thorium phosphate. I characteristics of evolution during drying

    International Nuclear Information System (INIS)

    In order to obtain a transparent matrix for optical spectroscopy studies of doped ions, chemical conditions to get a gel and a xerogel of thorium phosphate have been investigated. Both are transparent for a long time. Transformation of the gel into xerogel under drying procedure has been followed by DTA, TGA, NMR and studied by a fluorescent probe UO22+. After thermal treatment of the amorphous xerogel we get the crystallized and opaque thorium orthophosphate. This amorphous → crystal transition was studied by far infrared spectroscopy and X rays

  1. Global Uranium And Thorium Resources: Are They Adequate To Satisfy Demand Over The Next Half Century?

    Science.gov (United States)

    Lambert, I. B.

    2012-04-01

    This presentation will consider the adequacy of global uranium and thorium resources to meet realistic nuclear power demand scenarios over the next half century. It is presented on behalf of, and based on evaluations by, the Uranium Group - a joint initiative of the OECD Nuclear Energy Agency and the International Atomic Energy Agency, of which the author is a Vice Chair. The Uranium Group produces a biennial report on Uranium Resources, Production and Demand based on information from some 40 countries involved in the nuclear fuel cycle, which also briefly reviews thorium resources. Uranium: In 2008, world production of uranium amounted to almost 44,000 tonnes (tU). This supplied approximately three-quarters of world reactor requirements (approx. 59,000 tU), the remainder being met by previously mined uranium (so-called secondary sources). Information on availability of secondary sources - which include uranium from excess inventories, dismantling nuclear warheads, tails and spent fuel reprocessing - is incomplete, but such sources are expected to decrease in market importance after 2013. In 2008, the total world Reasonably Assured plus Inferred Resources of uranium (recoverable at less than 130/kgU) amounted to 5.4 million tonnes. In addition, it is clear that there are vast amounts of uranium recoverable at higher costs in known deposits, plus many as yet undiscovered deposits. The Uranium Group has concluded that the uranium resource base is more than adequate to meet projected high-case requirements for nuclear power for at least half a century. This conclusion does not assume increasing replacement of uranium by fuels from reprocessing current reactor wastes, or by thorium, nor greater reactor efficiencies, which are likely to ameliorate future uranium demand. However, progressively increasing quantities of uranium will need to be mined, against a backdrop of the relatively small number of producing facilities around the world, geopolitical uncertainties and

  2. Safe management of wastes from the mining and milling of uranium and thorium ores

    International Nuclear Information System (INIS)

    Wastes from the mining and milling of uranium and thorium ores pose potential environmental and public health problems because of their radioactivity and chemical composition. This document consists of two parts: a Code of Practice (Part I) and a Guide to the Code (Part II). The Code sets forth the requirements for the safe and responsible handling of the wastes resulting from the mining and milling of uranium and thorium ores, while the Guide presents further guidance in the use of the Code together with some discussion of the technology and concepts involved

  3. Innovative once-through thorium fuel cycle for the PTVM LWR concept

    International Nuclear Information System (INIS)

    An advanced once-through thorium fuel cycle for the innovative reactor concept, termed the pressure tube light water reactor with variable moderator control (PTVM LWR), is proposed. The PTVM LWR makes use of a seed-blanket geometry, whereby the core is divided into separated regions of thorium fuel channel assemblies (blanket) and low-enriched uranium fuel channel assemblies (seed). A novel fuel management scheme based on two separate fuel flow routes (i.e., seed route and blanket route) is proposed and analyzed. Neutronic analysis indicates that the novel scheme has the potential to utilize both seed and blanket in an efficient manner. (author)

  4. Thorium determination in intercomparison samples and in some Romanian building materials by gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Thorium content in zircon sand, thorium ore and a thorium liquid sample, as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement, cement mill dust, fly coal ash, bricks and tile (28 samples) was determined by gamma-ray spectrometry. For the building materials, 226 Ra, 40 K and 137 Cs specific activities were also measured. All samples were kept tightly closed in the pots for about one month, to allow that the radioactive equilibrium among the gaseous radionuclides 222 Rn (238 U series), 220 Rn (232 Th series) and their daughter products be reached. 232 Th activity concentration was calculated from its daughter products 228 Ac, 212 Pb, 212 Bi and 208 Tl, assuming radioactive equilibrium among all 232Th decay chain isotopes. The activity concentrations of 226 Ra was calculated by 214 Pb and 214 Bi daughter products, assuming radioactive equilibrium among all 226 Ra decay chain isotopes. Zircon sand, thorium ore and a thorium liquid sample were analyzed in the frame of the European Commission Project 'Thematic network on the analysis of thorium and its isotopes in workplace materials', coordinated by the Health and Safety Laboratory HSL, Sheffield, United Kingdom. Thorium nitrate solution containing 232 Th in equilibrium with its daughter products and the two thorium minerals (without any prior treatment) were prepared as test samples by the Centre for Ionizing Radiation Metrology at the UK National Physical Laboratory (NPL), Teddington, England. The obtained 232 Th results are in good agreement with those of NPL for the liquid and ore samples (analyst/NPL ratios of 0.97 and 1.05, respectively) and rather good agreement for zircon sand (analyst/NPL ratio of 1.20). Sand, wood, tufa, asbestos-cement, cement mill dust, fly coal ash, tile, red and autoclaved cellular concrete (ACC) bricks collected from building material factories in different zones of Romania were investigated for natural and artificial radioactivity. The results were compared

  5. Nuclear data used in the analysis of thorium in the workplace

    International Nuclear Information System (INIS)

    The analysis of thorium in the workplace can be achieved using a variety of metrological techniques. The uncertainty on the final measured values will include components that arise from the uncertainties in the nuclear data that are used. These data include half-lives, branching ratios and gamma ray emission probabilities. It is important that a common, consistent and reliable data set is used in order to minimise the potential differences between analytical results. With particular reference to the problems associated with thorium analysis, some of the various sources of nuclear data are discussed and a recommended set of data is proposed. (author)

  6. Geological framework and thorium resources exploration condition of Georgia (The Caucasus)

    International Nuclear Information System (INIS)

    The Caucasus represents a Phanerozoic collisional orogeny, that formed along the Eurasian North continental margin, extends over 1200 km from the Caspian to Black Sea. Georgian republic is situated in the central part of Caucasus Region. Here are marked 3 ore occurrences of thorium : 1-in the Greater Caucasus (Th concentrations vary between 51 g/t - 3882 g/t); 2- in the Dzirula massif (Th concentrations vary between 117 g/t -266 g/t); 3- in Vakijvari orefield (Th concentrations vary between 185 g/t - 428 g/t). Based on these data thorium ore occurrences found in Georgia should be treated as prospective resources. (author)

  7. Arbuscular mycorrhiza reduces phytoextraction of uranium, thorium and other elements from phosphate rock

    DEFF Research Database (Denmark)

    Roos, Per; Jakobsen, Iver

    2008-01-01

    Uptake of metals from uranium-rich phosphate rock was studied in Medicago truncatula plants grown in symbiosis with the arbuscular mycorrhizal fungus Glomus intraradices or in the absence of mycorrhizas. Shoot concentrations of uranium and thorium were lower in mycorrhizal than in non......-fungus uptake systems. The results support the role of arbuscular mycorrhiza as being an important component in phytostabilization of uranium. This is the first study to report on mycorrhizal effect and the uptake and root-to-shoot transfer of thorium from phosphate rock. (c) 2007 Elsevier Ltd. All rights...

  8. Preparation of homogeneous thorium oxide powders for development of certified reference materials

    International Nuclear Information System (INIS)

    In view of the growing importance of Thorium Oxide (ThO2) as a fuel in nuclear power reactors, it is essential to develop Certified Reference Materials (CRMs) for trace level assay of ThO2 in order to validate analytical methods and also to assess the performance of an individual chemical laboratory. The present paper discusses the preparation of four batches of homogeneous Thorium Oxide (ThO2) powders on kilogram levels including a batch of ThO2 and Natural UO2 mixed oxide with varying amounts of impurities and also developing them as CRMs based on round robin tests. (author)

  9. LOCALIZATION OF 5f STATES IN VARIOUS URANIUM AND THORIUM OXIDES AND GLASSES

    OpenAIRE

    Petiau, J.; Calas, G.; Petit-Maire, D.; Bianconi, A; Benfatto, M.; Marcelli, A.

    1986-01-01

    XANES spectroscopy at M3, 4, 5 and L3 edges of uranium and thorium has been used to probe the unoccupied 5f electronic states and the local structure of uranium and thorium sites in oxides and glasses. The presence of 5f components in the U(6d) conduction band of oxides, due to hybridization between U(6d, 7s) and U(5f) is shown by a long asymmetric tail of the main absorption peak at its high energy side extending up to 12 eV. On the contrary the presence of narrow 5f localized unoccupied sta...

  10. Thorium Mono- and Bis(imido) Complexes Made by Reprotonation of cyclo-Metalated Amides

    OpenAIRE

    Bell, Nicola L.; Maron, Laurent; Arnold, Polly L

    2015-01-01

    Molecules containing actinide–nitrogen multiple bonds are of current interest as simple models for new actinide nitride nuclear fuels, and for their potential for the catalytic activation of inert hydrocarbon C–H bonds. Complexes with up to three uranium–nitrogen double bonds are now being widely studied, yet those with one thorium–nitrogen double bond are rare, and those with two are unknown. A new, simple mono(imido) thorium complex and the first bis(imido) thorium complex, K[Th(═NAr)N″3] a...

  11. Uranium thorium and potassium contents analysis of rocks in Changwat Narathiwat by gamma spectrometry

    OpenAIRE

    Kaewtubtim, P.; Changkain, S.

    2002-01-01

    Quantitative analysis of three radioactive elements (potassium, equivalent uranium, and equivalent thorium) in the granite rocks of the Triassic Age at 24 locations in Narathiwat province was carried out by using a gamma counter. It was found that potassium, equivalent uranium and equivalent thorium contents were on the average of 3.63% (in the range of 1.56-5.24%), 8.55 ppm (2.98-15.27 ppm) and 18.74 ppm (0.34- 52.14 ppm), respectively. It is worth noting that the radiation detected from the...

  12. A molecular dynamics study of the thermal properties of thorium oxide

    OpenAIRE

    Martin, Paul; David J. Cooke; Cywinski, R.

    2012-01-01

    There is growing interest in the exploitation of the thorium nuclear fuel cycle as an alternative to that of uranium. As part of a wider study of the suitability of thorium dioxide (thoria) as a nuclear fuel, we have used molecular dynamics to investigate the thermal expansion, oxygen diffusion, and heat capacity of pure thoria and uranium doped (1-10%) thoria between 1500K and 3600 K. Our results indicate that the thermal performance of the thoria matrix, even when doped with 10%U, is compar...

  13. Evaluation of two radiochemical procedures for the determination of uranium and thorium isotopes in coal samples

    International Nuclear Information System (INIS)

    Two procedures are presented for the sequential determination of uranium and thorium isotopes in coals. They are based on acid leaching on a hot plate, and on acid digestion in closed vessels using microwave irradiation. Both were applied to the analysis of International Atomic Energy Agency (IAEA) and National Institute of Standards and Technology (NIST) reference materials, and to the study of coals with different ranks. The greatest recoveries were obtained with the acid digestion method. This method was more effective than the leaching method for the extraction of the uranium isotopes in coals. The effectiveness of the thorium isotopes extraction was similar in the two methods. (author)

  14. A method for the rapid radiochemical analysis of uranium and thorium isotopes in impure carbonates.

    Science.gov (United States)

    Elyahyaoui, A; Zarki, R; Chiadli, A

    2003-01-01

    A simple method combining solvent extraction and electrodeposition procedures is described for the determination of the isotopic composition and content of uranium and thorium in travertine samples. The actinide elements are extracted with diethyl ether from a calcium nitrate solution. The isolation of the elements and the alpha source preparation are performed in two steps after the sample digestion. The acid leaching of samples is performed using both partial and total dissolution methods. High recoveries of both uranium and thorium and good alpha-spectra are obtained with both partial and total dissolution methods. PMID:12485673

  15. Solvent extraction of thorium from nitrate medium by TBP, Cyanex272 and their mixture

    International Nuclear Information System (INIS)

    The extraction behavior of thorium(IV) has been investigated with tri-butyl phosphate (TBP) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272) in kerosene from nitrate medium. The effect of operating variables including time, aqueous phase acidity (pH), extractant concentration and temperature were investigated. This study also examined the synergistic enhancement of the extraction of thorium(IV) from nitrate medium by mixtures of TBP and Cyanex272 for the first time. The optimum synergistic enhancement factor of 3.86 was obtained at a Cyanex272/TBP molar ratio of 1:4. (author)

  16. Is the bipyridyl thorium metallocene a low-valent thorium complex? A combined experimental and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wenshan; Lukens, Wayne W.; Zi, Guofu; Maron, Laurent; Walter, Marc D.

    2012-01-12

    Bipyridyl thorium metallocenes [5-1,2,4-(Me3C)3C5H2]2Th(bipy) (1) and [5-1,3-(Me3C)2C5H3]2Th(bipy) (2) have been investigated by magnetic susceptibility and computational studies. The magnetic susceptibility data reveal that 1 and 2 are not diamagnetic, but they behave as temperature independent paramagnets (TIPs). To rationalize this observation, density functional theory (DFT) and complete active space SCF (CASSCF) calculations have been undertaken, which indicated that Cp2Th(bipy) has indeed a Th(IV)(bipy2-) ground state (f0d0 2, S = 0), but the open-shell singlet (f0d1 1, S = 0) (almost degenerate with its triplet congener) is lying only 9.2 kcal/mol higher in energy. Complexes 1 and 2 react cleanly with Ph2CS to give [ 5-1,2,4-(Me3C)3C5H2]2Th[(bipy)(SCPh2)] (3) and [ 5-1,3-(Me3C)2C5H3]2Th[(bipy)(SCPh2)] (4), respectively, in quantitative conversions. Since no intermediates were observed experimentally, this reaction was also studied computationally. Coordination of Ph2CS to 2 in its S = 0 ground state is not possible, but Ph2CS can coordinate to 2 in its triplet state (S = 1) upon which a single electron transfer (SET) from the (bipy2-) fragment to Ph2CS followed by C-C coupling takes place.

  17. Indian President visits CERN

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    On 1 October, her Excellency Mrs Pratibha Devisingh Patil, President of India, picked CERN as the first stop on her official state visit to Switzerland. Accompanied by a host of Indian journalists, a security team, and a group of presidential delegates, the president left quite an impression when she visited CERN’s Point 2!   Upon arrival, Pratibha Patil was greeted by CERN Director General Rolf Heuer, as well as senior Indian scientists working at CERN, and various department directors. After a quick overview of the Organization, Rolf Heuer and the President addressed India’s future collaboration with CERN. India is currently an Observer State of the Organization, and is considering becoming an Associate Member State. A short stop in LHC operations gave Steve Myers and the Accelerator team the opportunity to take the President on a tour through the LHC tunnel. From there, ALICE’s Tapan Nayak and Spokesperson Paolo Giubellino took Pratibha Patil to the experiment&am...

  18. Historicizing Indian psychiatry

    OpenAIRE

    Basu, Amit Ranjan

    2005-01-01

    Our historical endeavour to map Indian psychiatry has largely remained linear, positivistic and evolutionary. Whether it starts from the ancient times or modern, it shows our past as a tale of victory for the western science, without questioning the borrowed paradigm. The use of historical methods for serious enquiry of psychiatry has been ignored. Emergence of a new genre of historicism that is critical of both colonialism and psychiatry as a universal science, has raised hopes to critically...

  19. Indian scales and inventories

    OpenAIRE

    Venkatesan, S

    2010-01-01

    This conceptual, perspective and review paper on Indian scales and inventories begins with clarification on the historical and contemporary meanings of psychometry before linking itself to the burgeoning field of clinimetrics in their applications to the practice of clinical psychology and psychiatry. Clinimetrics is explained as a changing paradigm in the design, administration, and interpretation of quantitative tests, techniques or procedures applied to measurement of clinical variables, t...

  20. Indian Vacuum Society: The Indian Vacuum Society

    Science.gov (United States)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  1. Indian Women: An Historical and Personal Perspective

    Science.gov (United States)

    Christensen, Rosemary Ackley

    1975-01-01

    Several issues relating to Indian women are discussed. These include (1) the three types of people to whom we owe our historical perceptions of Indian women, (2) role delineation in Indian society; (3) differences between Indian women and white women, and (4) literary role models of Indian women. (Author/BW)

  2. Will the "Real" Indians Please Stand Up?

    Science.gov (United States)

    Pewewardy, Cornel

    1998-01-01

    Explores what it means to be an American Indian in an era in which nearly half of the identifiable Indians live off the reservations and in urban areas. As the principal definition of "Indian-ness" today, the issue of blood quantum leads to misunderstandings. Being an Indian, to the author, is being a person connected to a tribe. (SLD)

  3. A preparation method of thorium nitrides and their oxidation behavior

    International Nuclear Information System (INIS)

    In the preparation of ThN, thermal decomposition of Th3N4 has been performed under various conditions and the kind of products has been examined as a function of temperature and time. In the Th-N-O system there exist ThN, Th3N4, ThO2, and Th2N2O as solid phases. The thermodynamic stability of these solid compounds has been evaluated as a function of P(O2) and P(N2) and compared with the experimental results. One of the main aims in this work is to explore the oxidation behaviour of thorium nitrides. Preliminary oxidation experiments of ThN and Th3N4 gave the same result. From the study of the air oxidation of Th3N4, it was found that the oxidation product obtained close to room temperature exhibited only one or more diffuse reflections in its diffraction pattern, suggesting that the product may be of a poor crystalline nature. In order to reveal the dependence of the crystallinity of the product on the oxidation temperature, powdered Th3N4 was exposed to air for one week at 0, 50, and 100degC and the product was examined by X-ray diffraction. In order to prepare ThO2 with a wide variety of degrees of crystallinity, poorly-crystallized ThO2, which is produced by the air oxidation of Th3N4 at 50degC, was heat-treated at temperatures ranging from 200 to 1,400degC in air and vacuum. The degree of crystallinity of ThO2 heat-treated at and below 1000degC is discussed in terms of the number of detected peaks in the X-ray diffraction patterns, and above 1100degC in terms of the Kα doublet resolution of detected peaks. (author). 11 refs., 7 figs., 6 tabs

  4. Working Women: Indian Perspective

    Directory of Open Access Journals (Sweden)

    Dharmendra MEHTA

    2014-06-01

    Full Text Available In India, due to unprecedented rise in the cost of living, ris-ing prices of commodities, growing expenses on children ed-ucation, huge rate of unemployment, and increasing cost of housing properties compel every Indian family to explore all the possible ways and means to increase the household income. It is also witnessed that after globalization Indian women are able to get more jobs but the work they get is more casual in nature or is the one that men do not prefer to do or is left by them to move to higher or better jobs. Working women refers to those in paid employment. They work as lawyers, nurses, doctors, teachers and secretaries etc. There is no profession today where women are not employed. University of Oxford’s Professor Linda Scott recently coined the term the Double X Economy to describe the global economy of women. The present paper makes an attempt to discuss issues and challenges that are being faced by Indian working women at their respective workstations.

  5. Indian cosmogonies and cosmologies

    Directory of Open Access Journals (Sweden)

    Pajin Dušan

    2011-01-01

    Full Text Available Various ideas on how the universe appeared and develops, were in Indian tradition related to mythic, religious, or philosophical ideas and contexts, and developed during some 3.000 years - from the time of Vedas, to Puranas. Conserning its appeareance, two main ideas were presented. In one concept it appeared out of itself (auto-generated, and gods were among the first to appear in the cosmic sequences. In the other, it was a kind of divine creation, with hard work (like the dismembering of the primal Purusha, or as emanation of divine dance. Indian tradition had also various critiques of mythic and religious concepts (from the 8th c. BC, to the 6c., who favoured naturalistic and materialistic explanations, and concepts, in their cosmogony and cosmology. One the peculiarities was that indian cosmogony and cosmology includes great time spans, since they used a digit system which was later (in the 13th c. introduced to Europe by Fibonacci (Leonardo of Pisa, 1170-1240.

  6. BIA Indian Lands Dataset (Indian Lands of the United States)

    Data.gov (United States)

    Federal Geographic Data Committee — The American Indian Reservations / Federally Recognized Tribal Entities dataset depicts feature location, selected demographics and other associated data for the...

  7. A Review of Thorium Utilization as an option for Advanced Fuel Cycle-Potential Option for Brazil in the Future

    International Nuclear Information System (INIS)

    Since the beginning of Nuclear Energy Development, Thorium was considered as a potential fuel, mainly due to the potential to produce fissile uranium 233. Several Th/U fuel cycles, using thermal and fast reactors were proposed, such as the Radkwoski once through fuel cycle for PWR and VVER, the thorium fuel cycles for CANDU Reactors, the utilization in Molten Salt Reactors, the utilization of thorium in thermal (AHWR), and fast reactors (FBTR) in India, and more recently in innovative reactors, mainly Accelerator Driven System, in a double strata fuel cycle. All these concepts besides the increase in natural nuclear resources are justified by non proliferation issues (plutonium constrain) and the waste radiological toxicity reduction. The paper intended to summarize these developments, with an emphasis in the Th/U double strata fuel cycle using ADS. Brazil has one of the biggest natural reserves of thorium, estimated in 1.2 millions of tons of ThO2, as will be reviewed in this paper, and therefore RandD programs would be of strategically national interest. In fact, in the past there was some projects to utilize Thorium in Reactors, as the ''Instinto/Toruna'' Project, in cooperation with France, to utilize Thorium in Pressurized Heavy Water Reactor, in the mid of sixties to mid of seventies, and the thorium utilization in PWR, in cooperation with German, from 1979-1988. The paper will review these initiatives in Brazil, and will propose to continue in Brazil activities related with Th/U fuel cycle

  8. Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range.

    Science.gov (United States)

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-07-01

    A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0-1,200 and 0-2,000 μg L(-1) Th and U, respectively). Limits of detection reached are 5.9 ηg L(-1) of uranium and 60 ηg L(-1) of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method.

  9. Determination of ultratrace amounts of uranium and thorium in aluminium and aluminium alloys by electrothermal vaporization/ICP-MS

    International Nuclear Information System (INIS)

    A method has been developed for determining the 0.01 ng g-1 level of uranium and thorium in aluminium and aluminium alloys by electrothermal vaporization (ETV)/ICP-MS. This method was found to be significantly interfered with any matrices or other elements contained. An ion-exchange technique was therefore applied to separate uranium and thorium from aluminium and other elements. It was known that uranium are adsorbed on an anion-exchange resin and thorium are adsorbed on cation-exchange resin. However, aluminium and copper were eluted with 6 M hydrochloric acid. Dissolve the sample with hydrochloric acid containing copper which was added for analysis of pure aluminium, and oxidize with hydrogen peroxide. Concentration of hydrochloric acid in the solution was adjusted to 6 M, and then passed the solution through the mixed ion-exchange resin column. After the uranium and thorium were eluted with 1 M hydrofluoric acid-0.1 M hydrochloric acid, the solution was evaporated to dryness. It was then dissolved with 1 M hydrochloric acid. Uranium and thorium were analyzed by ETV/ICP-MS using tungsten and molybdenum boats, respectively, since the tungsten boat contained high-level thorium and the molybdenum boat contained uranium. The determination limit of uranium and thorium were 0.003 and 0.005 ng g-1, respectively. (author)

  10. Reaction of thorium(IV) with tris[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine trisodium salt as a spectrophotometric method for the determination of phosphate and thorium(IV)

    International Nuclear Information System (INIS)

    Thorium (IV) reacts with tris[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine trisodium salt (THT) to give a 1:3 dark red complex between pH 4.8 and 7.0. Sandell's sensitivity of the colour reaction is 0.0063 μg cm-2 for thorium at a lambdasub(max.) of 535 nm. Phosphate is the only anion which decomposes the thorium -THT complex, quantitatively replacing the THT from the complex. Phosphate can therefore be determined indirectly in the range 5.5-65 μg per 25 ml. (author)

  11. The concentrations of uranium, thorium and potasium in various cement products marketed in Indonesia

    International Nuclear Information System (INIS)

    The presence of natural radioactivity of nine samples from eight cement production companies in Indonesia have been analyzed. Natural radioactivity i.e uranium, thorium, and potassium in cements were determinated using γ-rays spectrometry method. All nine samples were measured after equilibrium conditions. The concentration of uranium was determined from the average concentrations of the 214Pb and 214Bi, thorium was determined from the average concentrations of the 212Pb and 228Ac, and that of potassium was determined from concentration of the 40K. The calculated uranium concentrations in cements were 4.6 - 18 µg/g with a mean value of 8.8 µg/g, thorium 2.3 - 10.8 µg/g with a mean value of 4.8 µg/g, and potassium 1638 - 6271 µg/g with a mean value of 4189 µg/g. The uranium concentrations were higher than those of the world average value, meanwhile thorium and potassium concentrations were lower. The contribution of gamma-dose from cements were lower than dose limit for building material because the calculated radium equivalent (Raeq) activity was 147 Bq/kg, meanwhile the gamma-dose limit for building material was 1.5 mSv per year, that was equivalent to 370 Bq/kg (Raeq). (author)

  12. Structural phase transition and elastic properties of thorium pnictides at high pressure

    Indian Academy of Sciences (India)

    Kuldeep Kholiya; B R K Gupta

    2007-04-01

    In the present paper we have pointed out the weaknesses of the approach by Aynyas et al [1] to study the structural phase transition and elastic properties of thorium pnictides. The calculated values of phase transition pressure and other elastic properties using the realistic and actual approach are also given and compared with the experimental and previous theoretical work.

  13. Digestion Study of Water Leach Purification (WLP) Residue for Possibility of Thorium Extraction

    International Nuclear Information System (INIS)

    Water leach purification (WLP) is the main residue being produced by Lynas Advanced Materials Plant (LAMP). During rare earths elements extraction process, thorium is removed completely to WLP. The objective of this study was to extract thorium from WLP in order to reduce the level of radioactivity and to store Th for future nuclear fuel. Alkali and concentrated acids process was used to recover the Th from WLP. The concentration of Th and U in WLP was determined by Instrumental Neutron Activation Analysis (INAA) and found to be 1952.9 ± 17.6 mg/ kg and 17.2 ± 2.4 mg/ kg respectively. Digestion process of WLP via sodium hydroxide, concentrated nitric and sulphuric acids using different time and temperature has been tested. The Th concentrations in liquid phrase were determined by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). In both processes less than 5 % recovery of Th has been achieved. This study showed that very low Th recovery was achieved due to thorium was probably converted into refractory and insoluble form through the calcination stage of LAMP processing. Therefore different techniques should be used to recover the thorium. (author)

  14. Radium accumulation in animal thyroid glands: a possible method for uranium and thorium prospecting

    International Nuclear Information System (INIS)

    A method of prospecting for uranium and thorium is proposed based on uptake of their radioactive daughters, 226Ra and 228Ra, by plants, the collection of plant material by herbivores, the concentration of the radioactive species by specific animal tissues, and the subsequent gamma-ray analysis of the tissues

  15. Analysis of the thorium axial blanket experiments in the proteus reactor

    Energy Technology Data Exchange (ETDEWEB)

    White, J.R.; Ingersoll, D.T.

    1980-12-01

    Detailed analysis has been completed for the ThO/sub 2/ and Th-metal axial blanket experiments performed at the Swiss PROTEUS critical facility in order to compare reaction rates and neutron spectra measured in prototypic GCFR configurations with calculated results. The PROTEUS configurations allowed the analysis of infinitely dilute thorium data in a PuO/sub 2//UO/sub 2/ fast lattice spectrum at core center as well as the analysis of resonance self-shielding effects in the thorium-bearing axial blankets. These comparisons indicate that significant deficiencies still exist in the latest evaluated infinitely dilute thorium data file. Specifically, the analysis showed that the /sup 232/Th capture is underpredicted by ENDF/B-IV data, and the discrepancies are further exaggerated by ENDF/B-V data. On the other hand, ENDF/B-V /sup 232/Th fission data appear to be significantly improved relative to ENDF/B-IV data, while discrepancies are extremely large for the (n,2n) process in both data files. Finally, the (n,n') cross sections for thorium also appear improved in ENDF/B-V, except for a small energy range just above the 50 keV threshold. Therefore, these combined data deficiencies suggest that relatively large uncertainties should be associated with many of the results obtained from recent fast reactor alternate fuel cycle analyses. 38 figures, 12 tables.

  16. X-ray spectrometric determination of thorium in bone and other biological materials

    International Nuclear Information System (INIS)

    An x-ray spectrometric method has been developed for the determination of thorium in bone and other biological materials. The limit of detection at the 95% confidence level is 20 ng. This corresponds to a concentration of 2 ppb in a 10-g sample of bone ash

  17. Thorium utilization in fast breeder reactors and in cross-progeny fuel cycles

    International Nuclear Information System (INIS)

    Thorium fuel cycles have to be closed since the benefit is obtained only when the 233U is used. India is the only country in the world, which has extensive facilities for reprocessing of irradiated Uranium and Thorium-based fuels, thermal reactors moderated by light and heavy water and 500 MWe LMFBRs. The cross-progeny fuel cycles would be a natural vision to pursue for India. This paper was written in 1982 and presented at the U.S. Japan Seminar on Thorium fuel cycle held in October 1982. The calculations performed and the results quoted in this paper are of that vintage. However, the cross section data for Th and other materials has not changed significantly since that time. The same holds for the methodologies in computer codes, diffusion theory and the other methodologies employed in this paper, versus those in computer codes currently in use. This paper is being submitted to remind the community that with the introduction of GEN IV LMFBRs, other possibilities for thorium utilization could spring forth and should be studied further and in more depth

  18. Thorium in the workplace: Results from a European-based measurement comparison Project

    International Nuclear Information System (INIS)

    A series of comparisons were conducted to test the capabilities of a range of metrological techniques and analytical laboratories engaged in the assay of thorium in the workplace. The results of these exercises are presented together with the decision criteria used to determine whether results are significantly different from the true value. The discussion highlights those aspects which warrant closer and further attention. (author)

  19. Uranium and thorium uptake by live and dead cells of Pseudomonas Sp

    International Nuclear Information System (INIS)

    This study presents uptake of uranium (U) and thorium (Th) by live and dead cells of Pseudomonas Sp. Increasing concentration of U and Tb showed decrease in absorption by Pseudomonas Sp. Dead cells of Pseudomonas Sp. exhibited same or more uptake of U and Th than living cells. Increasing temperature promotes uptake of U and Th by Pseudomonas Sp. (author)

  20. Production of chelating agents by Pseudomonas aeruginosa grown in the presence of thorium and uranium

    International Nuclear Information System (INIS)

    Chelating agents produced by microorganisms enhance the dissolution of iron increasing the mobility and bioavailability of the metal. Since some similarities exist in the biological behavior of ferric, thorium and uranyl ions, microorganisms resistant to these metals and which grow in their presence may produce sequestering agents of Th and U, and other metals in a manner similar to the complexation of iron by siderophores. The ability of P. aeruginosa to elaborate sequestering agents in medium containing thorium or uranium salts was tested. Uranium has a stronger inhibitory effect on growth of the organism than thorium at similar concentrations. Analyses of the culture media have shown, that relative to the control, and under the experimental conditions used, the microorganisms have produced several new chelating agents for thorium and uranium. Extracts containing these chelating agents have been tested for their decorporation potential. In vitro mouse liver bioassay and in vivo mouse toxicity tests indicate that their efficiency is comparable to DTPA and DFOA and that they are virtually non-toxic to mice. The bacterially produced compounds resemble, but are not identical to the known iron chelating siderophores isolated from microorganisms. Some of their chemical properties are also discussed. (author)

  1. Some applications of x-ray fluorescence spectrography to the determination of uranium and thorium

    International Nuclear Information System (INIS)

    Several methods for the determination of uranium and thorium by X-ray fluorescence spectrography are described. In pure solutions the sensitivity for these elements is 5-10 ppm. For solutions containing gross concentrations of impurities, strontium is added as an internal standard. Precision and accuracy of the determinations are about 1% when working in the optimum concentration range. (author)

  2. Evaluation of U-Zr hydride fuel for a thorium fuel cycle in an RTR concept

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Taek; Cho, Nam Zin [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    In this paper, we performed a design study of a thorium fueled reactor according to the design concept of the Radkowsky Thorium Reactor (RTR) and evaluated its overall performance. To enhance its performance and alleviate its problems, we introduced a new metallic uranium fuel, uranium-zirconium hydride (U-ZrH{sub 1.6}), as a seed fuel. For comparison, typical ABB/CE-type PWR based on SYSTEM 80+and standard RTR-type thorium reactor were also studied. From the results of performance analysis, we could ascertain advantages of RTR-type thorium fueled reactor in proliferation resistance, fuel cycle economics, and back-end fuel cycle. Also, we found that enhancement of proliferation resistance and safer operating conditions may be achieved by using the U-ZrH{sub 1.6} fuel in the seed region without additional penalties in comparison with the standard RTR`s U-Zr fuel. 6 refs., 2 figs., 6 tabs. (Author)

  3. Measurement of nuclides of uranium and thorium series of disequilibrium using γ-spectroscopy

    Institute of Scientific and Technical Information of China (English)

    刘广山; 黄奕普; 李静; 叶林

    2002-01-01

    The decay dynamic equations of two daughters were resolved as initial activities of daughters are not zero, and gave calculation formula of activities for measuring uranium and thorium series of disequilibrium using γ-spectroscopy. 238U, 234Th, 226Ra, 222Rn, 228Ra, 228Th, 224Ra, 212pb, 210pb and 40K in two sediment samples were determined as application.

  4. Comparison of the radiological impacts of thorium and uranium nuclear fuel cycles

    International Nuclear Information System (INIS)

    This report compares the radiological impacts of a fuel cycle in which only uranium is recycled, as presented in the Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel in Light Water Cooled Reactors (GESMO), with those of the light-water breeder reactor (LWBR) thorium/uranium fuel cycle in the Final Environmental Statement, Light Water Breeder Reactor Program. The significant offsite radiological impacts from routine operation of the fuel cycles result from the mining and milling of thorium and uranium ores, reprocessing spent fuel, and reactor operations. The major difference between the impacts from the two fuel cycles is the larger dose commitments associated with current uranium mining and milling operations as compared to thorium mining and milling. Estimated dose commitments from the reprocessing of either fuel type are small and show only moderate variations for specific doses. No significant differences in environmental radiological impact are anticipated for reactors using either of the fuel cycles. Radiological impacts associated with routine releases from the operation of either the thorium or uranium fuel cycles can be held to acceptably low levels by existing regulations

  5. Uranium and thorium sequential separation from norm samples by using a SIA system.

    Science.gov (United States)

    Mola, M; Nieto, A; Peñalver, A; Borrull, F; Aguilar, C

    2014-01-01

    This study presents a sequential radiochemical separation method for uranium and thorium isotopes using a novel Sequential Injection Analysis (SIA) system with an extraction chromatographic resin (UTEVA). After the separation, uranium and thorium isotopes have been quantified by using alpha-particle spectrometry. The developed method has been tested by analyzing an intercomparison sample (phosphogypsum sample) from International Atomic Energy Agency (IAEA) with better recoveries for uranium and thorium than the obtained by using a classical method (93% for uranium using the new methodology and 82% with the classical method, and in the case of thorium the recoveries were 70% for the semi-automated method and 60% for the classical strategy). Afterwards, the method was successfully applied to different Naturally Occurring Radioactive Material (NORM) samples, in particular sludge samples taken from a drinking water treatment plant (DWTP) and also sediment samples taken from an area of influence of the dicalcium phosphate (DCP) factory located close to the Ebro river reservoir in Flix (Catalonia). The obtained results have also been compared with the obtained by the classical method and from that comparison it has been demonstrated that the presented strategy is a good alternative to existing methods offering some advantages as minimization of sample handling, reduction of solvents volume and also an important reduction of the time per analysis.

  6. Process for dissolving thorium and/or plutonium oxide of low solubility

    International Nuclear Information System (INIS)

    In order to dissolve thorium and/or plutonium oxide of low solubility, particularly dioxides such as ThO2, PuO2 or the mixed oxide (U/Pu)O2, these oxides are heated inside a gas-tight closed vessel (autoclave) in concentrated nitric oxide (HNO3) free of fluoride. (orig./HP)

  7. Removal of Uranium and Thorium from Kvanefjeld Rare Earth Intermediate Product

    International Nuclear Information System (INIS)

    Rare earth elements are commonly encountered in close geological association with radioactive minerals. In particular, thorium is often found in the same minerals as rare earth elements, making their combined treatment necessary. The paper discusses the metallurgical flowsheet developed for the Kvanefjeld rare earth and uranium deposit located in southern Greenland. The Kvanefjeld and associated deposits are well recognized as one of the largest rare earth and uranium deposits in the world. The minerals which contain the rare earth elements also contain economically viable amounts of uranium and potentially economically viable amounts of thorium. Metallurgical studies using flotation have been successful in producing a high grade concentrate which consists of 13% rare earth oxide, 0.2% triuranium octaoxide and 0.8% thorium. Due to the unique nature of the minerals contained within the deposit, a customized hydrometallurgical flowsheet was developed to treat the concentrate. The hydrometallurgical flowsheet has been well tested and is capable of producing a high grade mixed rare earth product which is very low in uranium and thorium. A separate uranium oxide product can also be produced using commercially established solvent extraction. The Kvanefjeld project is currently at the feasibility study stage, with metallurgical designs of both the concentrator and hydrometallurgical plant well advanced. The paper discusses the metallurgical flowsheet and show the deportment of NORM throughout the flowsheet. The issues of NORM deportment and strategies for removal and safe disposal are also discussed. (author)

  8. On the retention of uranyl and thorium ions from radioactive solution on peat moss

    Energy Technology Data Exchange (ETDEWEB)

    Humelnicu, Doina, E-mail: doinah@uaic.ro [' Al.I. Cuza' University of Iasi, Faculty of Chemistry, Bd. 11 Carol I Boulevard, 700506 Iasi (Romania); Bulgariu, Laura; Macoveanu, Matei [Technical University ' Gh. Asachi' of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, Bd. D. Mangeron, 71A, 700050 Iasi (Romania)

    2010-02-15

    The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO{sub 3} and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss was selected as it is available in nature, in any amount, as a cheap and accessible sorbent. Study on desorption of such ions led to the conclusion that the most favourable desorptive reagent for the uranyl ions is Na{sub 2}CO{sub 3} 1 M while, for the thorium ions is HCl 1 M. The results obtained show that the parameters here under investigation exercise a significant effect on the sorption process of the two ions. Also, the investigations performed recommend the peat moss treated with a base as a potential sorbent for the uranyl and thorium ions from a radioactive aqueous solution.

  9. Thorium fuel cycle development activities in India (a decade of progress: 1981-1990)

    International Nuclear Information System (INIS)

    The report comprises of 72 papers on various aspects of thorium fuel cycle. These papers report the research work carried out at the Bhabha Atomic Research Centre, Bombay and other units of the Department of Atomic Energy during the decade 1981-1990. figs., tabs

  10. Thorium determination in thorotrast patient organs using inductively coupled plasma mass spectrometry and imaging plate autoradiography

    International Nuclear Information System (INIS)

    In this study inductively coupled plasma mass spectrometry (ICP-MS) have been used for the determination of Th in liver and spleen collected from autopsy subjects in Thorotrast patients to obtain useful information for dosimetry. The applicability of an imaging plate autoradiography technique for the determination of thorium distributions in organs to obtain information related to microdosimetry has also been evaluated

  11. Performing Indian Dance in Malaysia

    OpenAIRE

    Thiagarajan, Premalatha

    2012-01-01

    "Performing Indian Dance" is an interdisciplinary project that reveals the dynamics of ethnicity, gender, and sexuality in Malaysian Indian dance. I demonstrate that the emergence of prominent multi-ethnic male dancers in Malaysia is enabled by a unique configuration of "bumiputera" ("son of soil") ethnic-based state discourse, cosmopolitanism (ability to move fluently across multiple spaces), Indian dance institutional structures, global capitalism, and gender mobility, which simultaneously ...

  12. Thorium-based fuel cycles: Reassessment of fuel economics and proliferation risk

    Energy Technology Data Exchange (ETDEWEB)

    Serfontein, Dawid E., E-mail: Dawid.Serfontein@nwu.ac.za [Senior Lecturer at the School of Mechanical and Nuclear Engineering, North West University (PUK-Campus), PRIVATE BAG X6001, Internal Post Box 360, Potchefstroom 2520 (South Africa); Mulder, Eben J. [Professor at the School of Mechanical and Nuclear Engineering, North West University (South Africa)

    2014-05-01

    At current consumption and current prices, the proven reserves for natural uranium will last only about 100 years. However, the more abundant thorium, burned in breeder reactors, such as large High Temperature Gas-Cooled Reactors, and followed by chemical reprocessing of the spent fuel, could stretch the 100 years for uranium supply to 15,000 years. Thorium-based fuel cycles are also viewed as more proliferation resistant compared to uranium. However, several barriers to entry caused all countries, except India and Russia, to abandon their short term plans for thorium reactor projects, in favour of uranium/plutonium fuel cycles. In this article, based on the theory of resonance integrals and original analysis of fast fission cross sections, the breeding potential of {sup 232}Th is compared to that of {sup 238}U. From a review of the literature, the fuel economy of thorium-based fuel cycles is compared to that of natural uranium-based cycles. This is combined with a technical assessment of the proliferation resistance of thorium-based fuel cycles, based on a review of the literature. Natural uranium is currently so cheap that it contributes only about 10% of the cost of nuclear electricity. Chemical reprocessing is also very expensive. Therefore conservation of natural uranium by means of the introduction of thorium into the fuel is not yet cost effective and will only break even once the price of natural uranium were to increase from the current level of about $70/pound yellow cake to above about $200/pound. However, since fuel costs constitutes only a small fraction of the total cost of nuclear electricity, employing reprocessing in a thorium cycle, for the sake of its strategic benefits, may still be a financially viable option. The most important source of the proliferation resistance of {sup 232}Th/{sup 233}U fuel cycles is denaturisation of the {sup 233}U in the spent fuel by {sup 232}U, for which the highly radioactive decay chain potentially poses a large

  13. Uranium and thorium mining and milling: material security and risk assessment

    International Nuclear Information System (INIS)

    Full text: At present physical protection for the front end of the nuclear fuel cycle is typically at a significantly lower level than at any other part of the nuclear fuel cycle. In view of past experiences (Israel, South Africa, Pakistan, India) it is feasible to take into consideration some generic threat scenarios, potentially resulting in loss of control over uranium or thorium, respectively their concentrates, such as: illegal mining of an officially closed uranium- or thorium mine; covert diversion of uranium- or thorium ore whilst officially mining another ore; covert transport of radioactive ore or product, using means of public rail, road, ship, or air transport; covert en route diversion of an authorized uranium- or thorium transport; covert removal of uranium-or thorium ore or concentrate from an abandoned facility. The Stanford-Salzburg database on nuclear smuggling, theft, and orphan radiation sources (DSTO) contains information on trafficking incidents involving mostly uranium, but also some thorium, from 30 countries in five continents with altogether 113 incidents in the period 1991 to 2004. These activities range from uranium transported in backpacks by couriers in Afghanistan, to a terrorist organization purchasing land in order to mine covertly for uranium in Australia, and the clandestine shipment of almost two tons of uranium hexafluoride from Asia to Africa, using the services of a national airline. Potential participants in such illegal operations range from entrepreneurs to members of organized crime, depending on the level of sophistication of the operation. End-users and 'customers' of such illegal operations are suspected to be non-state actors, organizations or governments involved in a covert operation with the ultimate aim to acquire a sufficient amount of nuclear material for a nuclear device. The actual risk for these activities to succeed in the acquisition of an adequate amount of suitable radioactive material depends on one or

  14. LFTR: in search of the ideal pathway to thorium utilization-development program and current status

    International Nuclear Information System (INIS)

    Thorium has gained substantial attention as a potential energy source that could rival and eventually replace fossil fuels as humanity's primary energy source. This could not have come at a more opportune time as concerns about global climate change from CO2 emissions and the approaching spectre of finite fossil fuel resources create serious challenges for the continuation of our advanced industrial societies, which are reliant on readily available and affordable energy. Thorium also potentially represents the catalyst with which the nuclear industry could reinvent itself and finally gain widespread public acceptance. There are many opinions on how to utilize thorium as a fuel, but the question of what constitutes an 'ideal' pathway has mostly been under-emphasized. Many specific characteristics of the thorium fuel cycle can differ significantly depending on the conditions and methodologies of utilization; characteristics such as safety, efficiency, waste profile and volume, and fissile protection can vary greatly according to reactor design and utilization philosophy. With thorium, we have been given an opportunity to start over, a blank slate. Therefore, in imagining the 'Thorium Economy' to come, it behoves the scientific and engineering communities to consider the most 'elegant' solution physically possible-what constitutes the 'ideal' and is it possible to reconcile it with what is both economically and technically practical? The characteristics desired of an 'ideal' nuclear reactor, in the areas of safety, efficiency, economy, and sustainability, and the 5 key design choices that could enable such a reactor will be discussed. This will be followed by an overview of the Liquid Fluoride Thorium Reactor, a 2-fluid Molten Salt Reactor currently under development by Flibe Energy in the United States. LFTR is a direct descendant of the MSRE, which was developed at Oak Ridge National Laboratory (ORNL) in the

  15. Thorium-based fuel cycles: Reassessment of fuel economics and proliferation risk

    International Nuclear Information System (INIS)

    At current consumption and current prices, the proven reserves for natural uranium will last only about 100 years. However, the more abundant thorium, burned in breeder reactors, such as large High Temperature Gas-Cooled Reactors, and followed by chemical reprocessing of the spent fuel, could stretch the 100 years for uranium supply to 15,000 years. Thorium-based fuel cycles are also viewed as more proliferation resistant compared to uranium. However, several barriers to entry caused all countries, except India and Russia, to abandon their short term plans for thorium reactor projects, in favour of uranium/plutonium fuel cycles. In this article, based on the theory of resonance integrals and original analysis of fast fission cross sections, the breeding potential of 232Th is compared to that of 238U. From a review of the literature, the fuel economy of thorium-based fuel cycles is compared to that of natural uranium-based cycles. This is combined with a technical assessment of the proliferation resistance of thorium-based fuel cycles, based on a review of the literature. Natural uranium is currently so cheap that it contributes only about 10% of the cost of nuclear electricity. Chemical reprocessing is also very expensive. Therefore conservation of natural uranium by means of the introduction of thorium into the fuel is not yet cost effective and will only break even once the price of natural uranium were to increase from the current level of about $70/pound yellow cake to above about $200/pound. However, since fuel costs constitutes only a small fraction of the total cost of nuclear electricity, employing reprocessing in a thorium cycle, for the sake of its strategic benefits, may still be a financially viable option. The most important source of the proliferation resistance of 232Th/233U fuel cycles is denaturisation of the 233U in the spent fuel by 232U, for which the highly radioactive decay chain potentially poses a large radiation as well as a detection risk

  16. Biogeochemical investigation in south eastern Andhra Pradesh: the distribution of rare earths, thorium and uranium in plants and soils

    Energy Technology Data Exchange (ETDEWEB)

    Raju, K.K.; Raju, A.N. [Sri Venkateswara Univ., Tirupati (India). Dept. of Geology

    2000-09-01

    The concentration of rare earth elements (REE), thorium and uranium were determined by inductively coupled plasma mass spectrometry (ICP-MS) in the plant species, Pterocarpus santalinus, P. marsupium and P. dalbergioides, and the soils on which they were growing. Higher concentrations of lanthanum (La), cerium (Ce) were observed in both plants and soils. Large amounts of thorium and uranium were found in the soil. In all tree species, the concentration of REEs were higher in the heartwood than the leaves. The heartwood of P. santalinus accumulated larger quantities of uranium (average concentration of 1.22 ppm) and thorium (mean value of 2.57 ppm) than the other two species. (orig.)

  17. Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

    Directory of Open Access Journals (Sweden)

    F. Lidman

    2012-11-01

    Full Text Available The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2 up to a fourth-order stream (67 km2. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, suggesting that the concentrations of uranium and thorium in mineral soils are similar throughout the catchment. The fluxes of uranium and thorium were compared to a wide range of parameters characterising the investigated catchments and the chemistry of the stream water, e.g. soil concentrations of these elements, pH, TOC (total organic carbon, Al, Si and hydrogen carbonate, but it was concluded that the spatial variabilities in the fluxes of both uranium and thorium mainly were controlled by wetlands. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal wetlands that is large enough to control the transport of these elements. On the landscape scale approximately 65–80% of uranium and 55–65% of thorium entering a wetland were estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands was estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40%, indicating that wetlands play an important role for the biogeochemical cycling of uranium and thorium in the boreal forest landscape. The atmospheric deposition of uranium and thorium was also quantified, and its contribution to boreal streams was

  18. Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

    OpenAIRE

    H. Laudon; C. M. Mörth; F. Lidman

    2012-01-01

    The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and ...

  19. Biogeochemical investigation in south eastern Andhra Pradesh: the distribution of rare earths, thorium and uranium in plants and soils

    International Nuclear Information System (INIS)

    The concentration of rare earth elements (REE), thorium and uranium were determined by inductively coupled plasma mass spectrometry (ICP-MS) in the plant species, Pterocarpus santalinus, P. marsupium and P. dalbergioides, and the soils on which they were growing. Higher concentrations of lanthanum (La), cerium (Ce) were observed in both plants and soils. Large amounts of thorium and uranium were found in the soil. In all tree species, the concentration of REEs were higher in the heartwood than the leaves. The heartwood of P. santalinus accumulated larger quantities of uranium (average concentration of 1.22 ppm) and thorium (mean value of 2.57 ppm) than the other two species. (orig.)

  20. Comparison for thorium fuel cycle facilities of two different capacities for implementation of safeguards

    International Nuclear Information System (INIS)

    Highlights: • Facilities for implementation of safeguards for thorium fuel cycle have been compared. • Two concepts have been compared. • In one concept, the facilities are designed in hub and spoke concept. • In second concept the facilities are designed as self-contained concept. • The comparison is done on a number of factors, which affect safeguardability and proliferation resistance. -- Abstract: Thorium based nuclear fuel cycle has many attractive features, its inherent proliferation resistance being one of them. This is due to the presence of high energy gamma emitting daughter products of U232 associated with U233. This high energy gamma radiation also poses challenges in nuclear material accounting. A typical thorium fuel cycle facility has a number of plants including a fuel fabrication plant for initial and equilibrium core, a reprocessed U233 fuel fabrication plant, a reprocessing plant, a fuel assembly/disassembly plant and associated waste handling and management plants. A thorium fuel cycle facility can be set up to serve reactors at a site. Alternatively, one can follow a hub and spoke approach with a large thorium fuel cycle facility acting as a hub, catering to the requirements of reactors at several sites as spokes. These two concepts have their respective merits and shortcomings in terms of engineering and economics. The present paper is aimed at comparing the merits and challenges for implementation of safeguards on the two concepts viz. a large fuel cycle hub catering to reactors at several sites versus a small fuel cycle facility dedicated to reactors at a single site