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Sample records for thorium purification facility

  1. Recovery of thorium and rare earths by their peroxides precipitation from a residue produced in the thorium purification facility

    International Nuclear Information System (INIS)

    Freitas, Antonio Alves de

    2008-01-01

    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 1/2 =5.7y), known as meso thorium and Thorium-228(T 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)

  2. 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)

  3. Recovering of thorium contained in wastes from Thorium Purification Plant

    International Nuclear Information System (INIS)

    Brandao Filho, D.; Hespanhol, E.C.B.; Baba, S.; Miranda, L.E.T.; Araujo, J.A. de.

    1992-08-01

    A study has been developed in order to establish a chemical process for recovering thorium from wastes produced at the Thorium Purification Plant of the Instituto de Pesquisas Energeticas e Nucleares. The recovery of thorium in this process will be made by means of solvent extraction technique. Solutions of TBP/Varsol were employed as extracting agent during the runs. The influence of thorium concentration in the solution, aqueous phase acidity, volume ratio of the phases, percentage of TBP/Varsol and the contact time of the phases on the extraction of thorium and lanthanides was determined. (author)

  4. 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...

  5. PLUTONIUM PURIFICATION PROCESS EMPLOYING THORIUM PYROPHOSPHATE CARRIER

    Science.gov (United States)

    King, E.L.

    1959-04-28

    The separation and purification of plutonium from the radioactive elements of lower atomic weight is described. The process of this invention comprises forming a 0.5 to 2 M aqueous acidffc solution containing plutonium fons in the tetravalent state and elements with which it is normally contaminated in neutron irradiated uranium, treating the solution with a double thorium compound and a soluble pyrophosphate compound (Na/sub 4/P/sub 2/O/sub 7/) whereby a carrier precipitate of thorium A method is presented of reducing neptunium and - trite is advantageous since it destroys any hydrazine f so that they can be removed from solutions in which they are contained is described. In the carrier precipitation process for the separation of plutonium from uranium and fission products including zirconium and columbium, the precipitated blsmuth phosphate carries some zirconium, columbium, and uranium impurities. According to the invention such impurities can be complexed and removed by dissolving the contaminated carrier precipitate in 10M nitric acid, followed by addition of fluosilicic acid to about 1M, diluting the solution to about 1M in nitric acid, and then adding phosphoric acid to re-precipitate bismuth phosphate carrying plutonium.

  6. Historical and perspectives of thorium compounds production and purification at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.; Abrao, A.; Freitas, Antonio A.; Carvalho, Fatima M.S. de; Bergamaschi, Vanderlei S.; Cunha, Edgar F.; Ayoub, Jamil M.S.; Mindrisz, Ana C.

    2000-01-01

    The production and purification of some thorium compounds has been performed in the IPEN in the last 15 years. Some raw materials have been employed in this production, obtained from the monazite exploitation in industrial scale that it was performed in Sao paulo during the period 1948 until 1994. More than 160 t of high purity thorium nitrate were produced, purified by the solvent extraction process. The thorium nitrate has been supplied for the Brazilian portable gaslight industry to the production of Welsbach Mantle. Nowadays, a new facility is being designed and built. The main concern is the recovering of the production capacity, lost after some years of operation without suitable maintenance. This activity has an important strategic role, considering the huge Brazilian thorium resources and the renewed interest in thorium fuel cycle. This paper describes a brief historical background of thorium activities in the IPEN as well as their perspectives. (author)

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

    International Nuclear Information System (INIS)

    Ikuta, A.

    1977-01-01

    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 [pt

  8. Dosimetric assessment from 212Pb inhalation at a thorium purification plant

    International Nuclear Information System (INIS)

    Campos, M. P.; Pecequilo, B. R. S.

    2004-01-01

    At the Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo (Brazil)), there is a facility (thorium purification plant) where materials with high thorium concentrations are manipulated. In order to estimate afterwards the lung cancer risk for the workers, the thoron daughter ( 212 Pb) levels were assessed and the committed effective and lung committed equivalent doses for workers in place. A total of 28 air filter samples were measured by total alpha counting through the modified Kusnetz method, to determine the 212 Pb concentration. The committed effective dose and lung committed equivalent dose due to 212 Pb inhalation were derived from compartmental analysis following the ICRP 66 lung compartmental model, and ICRP 67 lead metabolic model. (authors)

  9. Recovering of thorium contained in wastes from Thorium Purification Plant; Reaproveitamento do torio contido em residuos provenientes da Usina de Purificacao do Torio

    Energy Technology Data Exchange (ETDEWEB)

    Brandao Filho, D; Hespanhol, E C.B.; Baba, S; Miranda, L E.T.; Araujo, J.A. de

    1992-08-01

    A study has been developed in order to establish a chemical process for recovering thorium from wastes produced at the Thorium Purification Plant of the Instituto de Pesquisas Energeticas e Nucleares. The recovery of thorium in this process will be made by means of solvent extraction technique. Solutions of TBP/Varsol were employed as extracting agent during the runs. The influence of thorium concentration in the solution, aqueous phase acidity, volume ratio of the phases, percentage of TBP/Varsol and the contact time of the phases on the extraction of thorium and lanthanides was determined. (author).

  10. Decommissioning of nuclear facilities involving operations with uranium and thorium

    International Nuclear Information System (INIS)

    Shum, E.Y.; Neuder, S.M.

    1990-01-01

    When a licensed nuclear facility ceases operation, the U.S. Nuclear Regulatory Commission (NRC) ensures that the facility and its site are decontaminated to acceptable levels so they may safely be released for unrestricted public use. Because specific environmental standards or broad federal guidelines governing release of residual radioactive contamination have not been issued, NRC has developed ad hoc cleanup criteria for decommissioning nuclear facilities that involved uranium and thorium. Cleanup criteria include decontamination of buildings, equipment, and land. We will address cleanup criteria and their rationale; procedures for decommissioning uranium/thorium facilities; radiological survey designs and procedures; radiological monitoring and measurement; and cost-effectiveness to demonstrate compliance

  11. Recovery and purification of rare earth elements and thorium

    International Nuclear Information System (INIS)

    Sungur, A.; Saygi, Z.; Yildiz, H.

    1985-01-01

    Rare earth elements and thorium found in the low-grade Eskisehir-Beylikahir ore have been recovered by HCl leaching, Lanthanides and thorium were separated and purified from the leach solutions through the precipitation sequence as double sulphate, hydroxide and oxalate. The Ln 2 O 3 and Th(OH) 4 products, finally obtained contained 36% Ce and 65% Th. The analysis of rare earth elements, thorium and other present ingredients were carried out by instrumental neutron activation analysis, atomic absorption spectroscopy, vis-spectroscopy and gravimetry. (author)

  12. 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)

    Seneda, Jose Antonio

    2006-01-01

    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 ThO 2 . 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)

  13. 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)

    Seneda, Jose Antonio

    2006-01-01

    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 ThO 2 . 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 σγ 0 = 14.6±0.7 mb was found, quite different from the σγ 0 = 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)

  14. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue

    International Nuclear Information System (INIS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-01-01

    Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th was found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM)

  15. Decommissioning an uranium and thorium facility: a radiation protection approach

    International Nuclear Information System (INIS)

    Feijo Vasques, Francisco Mario; Saburo Todo, Alberto; Mestre, Paulo Antonio

    2008-01-01

    Decommissioning means actions taken at the end of the useful life of a facility in retiring it from service with adequate regard for the health and safety of workers and members of the public. In the present work, we introduce a radiation protection approach for the removal of radioactive material to the extent that the facility or site becomes available for use without restriction. The facility to be decommissioned is a fuel cycle pilot plant that operated with natural uranium and thorium for almost two decades and then, kept inactive for about 10 years at the Nuclear and Energy Research Institute - IPEN. Even after this long period of inactivity, it has presented significant levels of radiation and contamination spread over the floor, walls, windows, doors and ceiling. The fuel cycle pilot plant was completely dismantled, remaining only the walls and the concrete structures. In this work we present the job done to restore the area. According to each step of dismantling a continuous monitoring of the contaminated surfaces was carried out including the survey of the deep material from the floor and walls. The material identified as radioactive waste was stored into appropriated metal drums. A radiation protection team guided this stage of the work, prescribing the tasks, and the amount of material that should be removed from floors, windows and ceiling. For this, repetitive surveys had to be done. The results of monitoring and contamination levels were analysed, thus guiding the next steps of the job. In this way radiation protection team took over the tasks, running the work with the purpose of achieving acceptable levels of radiation, restoring the area for unrestricted use. (author)

  16. Study on the use of macroporous cation exchange resins for the separation and purification of uranium from thorium

    International Nuclear Information System (INIS)

    Rastogi, R.K.; Mahajan, M.A.; Chaudhuri, N.K.

    1992-01-01

    The possibility of using macroporous cation exchange resins for the purification of uranium from thorium relevant to the final purification of uranium after reprocessing thorium breeder fuel was explored. Two macroporous cation exchange resins were studied and compared with a commonly used gel type resin. Batch experiments and column experiments were performed to generate equilibrium data and to optimise the procedure for the separation of U from Th under process condition. Under the same condition Tulsion T-42 gave product U containing 0.1% of Th, while Amberlyst-15 gave the product U containing 1% of Th. Loading and washing rates were much higher (120 ml/hr) than those used for gel type resins (40 ml/hr). Though the volume of wash required for >90% recovery of U is more than that required with the gel type resin the disadvantage due to that is more than compensated by the use of high flow rate of loading and washing to give higher throughput. Thus there is a definite advantage of U purification with macroporous resins as compared to usual gel type resins. (author). 23 refs., 3 figs., 10 tabs

  17. Comparison for thorium fuel cycle facilities of two different capacities for implementation of safeguards

    International Nuclear Information System (INIS)

    Gangotra, Suresh; Grover, R.B.; Ramakumar, K.L.

    2013-01-01

    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 U 232 associated with U 233 . 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 U 233 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

  18. Comparison for thorium fuel cycle facilities of two different capacities for implementation of safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Gangotra, Suresh, E-mail: sgangotra@yahoo.co.in; Grover, R.B.; Ramakumar, K.L.

    2013-09-15

    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 U{sup 232} associated with U{sup 233}. 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 U{sup 233} 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.

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

    International Nuclear Information System (INIS)

    Ramanujam, A.; Dhami, P.S.; Gopalakrishnan, V.; Mukherjee, A.; Dhumwad, R.K.

    1989-01-01

    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 HNO 3 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 HNO 3 . 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

  20. Active test of purification facility at Rokkasho reprocessing plant

    Energy Technology Data Exchange (ETDEWEB)

    Ishio, Takahiro; Sato, Nobuharu; Inaba, Makoto; Itagaki, Takashi [Purification Section, Plant Operation Department, Reprocessing Plant, Reprocessing Business Division, Japan Nuclear Fuel Limited, 4-108, Aza Okitsuke, Oaza Obuchi, Rokkasho-mura, Kamikita-gun, Aomori-ken (Japan)

    2009-06-15

    I. Introduction: At RRP, following the completion of Water Test, Chemical Test (CT) and Uranium Test (UT), the Active Test (AT) with actual spent fuel assemblies has been performed since March of 2006. This paper deals with the AT of the plutonium purification unit at RRP. II. Outline of plutonium purification unit: The plutonium purification unit purifies plutonium nitrate sent from the Separation Facility, and it has 5 pulsed columns and 4 mixer-settlers. Plutonium valence is adjusted to Pu{sup 4+} in plutonium nitrate sent from the Separation Facility, and then plutonium is extracted into organic phase (tri-butyl phosphate: TBP) in the extraction column. At this time, most of fission products remain in aqueous phase (nitric acid solution), which is discharged as raffinate through the diluent washing column. The fission products still contained in loaded organic solvent are removed in the FP scrubbing column, and then plutonium is stripped with nitric acid solution including hydroxylamine nitrate (HAN) as reducer. After TBP contained in purified plutonium nitrate solution is removed in the diluent washing bank with n-dodecane, it is sent to the plutonium concentration unit. Organic solvent used in the stripping column is sent to the plutonium barrier bank in order to remove remaining plutonium with uranous nitrate and hydrazine nitrate solution, and organic solvent is sent to the solvent regeneration unit. III. Active test results: The main purpose of the AT on the plutonium purification unit is (1) checking the performance of plutonium extraction and stripping, (2) checking the efficiency of diluent washing. III.A. Plutonium Extraction and Stripping performances: As a result of the neutron monitor profile on the extraction column during the representative operation, extraction was completed at the upper part of the column. As for the neutron monitor profile on the stripping column, stripping was performed at the lower part of the column. Plutonium concentration

  1. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium purification pilot plant; Separacao e recuperacao de chumbo-208 dos residuos de torio terras raras gerados na unidade piloto de purificacao de nitrato de torio

    Energy Technology Data Exchange (ETDEWEB)

    Seneda, Jose Antonio

    2006-07-01

    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 ThO{sub 2}. 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 {sigma}{gamma}{sup 0} = 14.6{+-}0.7 mb was found, quite different from the {sigma}{gamma}{sup 0} = 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)

  2. Decommissioning of Phosphoric Acid Purification Facility, PT Petrokimia Gresik

    International Nuclear Information System (INIS)

    Zainus Salimin; Nanang TS; Zaid, Ach.; Chotimah; Karyono

    2008-01-01

    Decommissioning of phosporic acid purification facility was the administrative and technical actions taken to allow the removal of some or all of the regulatory control from that facility exploit the phosphoric acid containing uranium. The site location of facility was cleaned up as the clean previous site (green land) for another site project utilization. Decommissioning activities covers the draining of solution or solid powder of remaining process on the equipment, decontamination of site location and equipment wall, dismantling of equipment, decontamination of equipment after dismantling, and decontamination of concrete floor and wall. Uranium contaminated liquid waste and organic solution was treated by bio-oxidation process using bacteria. Remaining solid powder from process (28 drums), contaminated material and equipment after decontamination (60 drums of fire brick, 31 pieces of equipment cut, 2 drums of ashes, 10 drums of active sludge from bio-oxidation process) and concrete splinter of 10 drums of 200 l volume per drum are the radioactive waste that must be sent to Radioactive Waste Technology Centre for its treatment. The non contaminated material and equipment (908 ton) can be reused for reprocessing, some of non contaminated sludge (14.4 m 3 ) and all of non contaminated filtrate water (353 m 3 ) from bio-oxidation process with toxic matters qualification which comply to the its limit values are released on the effluent release drain system of the plant. Clearance level utilizing for filtering contaminated material or equipment was an activity concentration of 1 Bq/g, surface contamination of 1 Bq/cm 2 , effective dose on the 50 cm distance from surface of contaminated material of 0.5 μSv/h (BAPETEN Regulation Letter No. 1459A/P101/PIBN/2008). Limit values for toxic matter are pH 6-9, COD 100 ppm and BOD 50 ppm (Gov. Regulation of East Java No. 45 year of 2002). (author)

  3. Status of thorium technology

    International Nuclear Information System (INIS)

    Garg, R.K.; Raghavan, R.V.; Karve, V.M.; Narayandas, G.R.

    1977-01-01

    Although a number of studies have been conducted in various countries to evolve reactor systems based on thorium fuel cycle, its use, so far, is limited to only a few reactors. However, for countries having large reserves of thorium, its utilization is of great significance for their nuclear power programmes. Reasonably assured world resources of thorium in the lower price range have been estimated at more than 500,000 tons of ThO 2 . While most of these resources are in placer deposits in various parts of the world, some vein deposits and uranium ores are other important sources of thorium. Monazite, the most important mineral of thorium, is found in the beach sand deposits along with other heavy minerals like ilmenite, rutile, zircon, and sillimanite etc. Mining of these deposits is usually carried out by suction dredging and separation of monazite from other minerals is effected by a combination of magnetic, electrostatic and gravity separation techniques. Chemical processing of monazite is carried out either by sulphuric acid or caustic treatment, followed by separation of the rare earths and thorium by partial precipitation or leaching. The thorium concentrate is further processed to obtain mantle grade thorium nitrate by chemical purification steps whereas solvent extraction using TBP is adopted for making nuclear-grade material. The purified thorium nitrate is converted to the oxide usually by precipitation as oxalate followed by calcination. The oxide is reduced directly with calcium or converted to the chloride or fluoride and then reduced by calcium or magnesium to obtain thorium metal. Various fuel designs based on the metal or its alloys, mixed oxides or carbides, and dispersed type fuel elements have been developed and accordingly, different fabrication techniques have been employed. Work on irradiation of thorium containing fuel elements and separation of U 233 is being carried out. This paper reviews the status of thorium technology in the world with

  4. Venturi purification device and its application in purification of gaseous waste of nuclear facilities

    International Nuclear Information System (INIS)

    Kong Jinsong; Yu Ren; Yang Huanlei

    2013-01-01

    The working principle of Venturi purification device and its purification of aerosol have been described. Then, taking the gaseous iodine as an example, the absorption process of insoluble gas pollutants is discussed, the calculation methods of the gas-liquid contact area, mass transfer rate and efficiency of mass transfer are educed, and the factors that affect the efficiency of mass transfer are analyzed. (authors)

  5. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    Science.gov (United States)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-02-01

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  6. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    International Nuclear Information System (INIS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-01-01

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232 Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted

  7. Thorium, Uranium and Rare Earth Elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas Advanced Materials Plant (LAMP)

    International Nuclear Information System (INIS)

    Al-Areqi, W.M.; Amran Abdul Majid; Sukiman Sarmani

    2013-01-01

    Full-text: Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6 Bq/ kg) whereas the Th and U concentrations in WLP were determined to be 1952.9 ± 17.6 ppm (7987.4 ± 71.9 Bq/ kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/ kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/ kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232 Th compared to Malaysian soil natural background (63 - 110 Bq/ kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6 % and 4.7 ± 0.1 % respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04 %, 1.6 %, 0.22 % and 0.06 % respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be re

  8. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    Energy Technology Data Exchange (ETDEWEB)

    AL-Areqi, Wadeeah M., E-mail: walareqi@yahoo.com; Majid, Amran Ab., E-mail: walareqi@yahoo.com; Sarmani, Sukiman, E-mail: walareqi@yahoo.com [Nuclear Science Programme, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia)

    2014-02-12

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  9. Summary of the last step of active test at separation facility and purification facility in Rokkasho Reprocessing Plant

    International Nuclear Information System (INIS)

    Kuroishi, Yuuki; Iseki, Tadahiro; Mitani, Akira; Takahashi, Naoki; Tsujimura, Akino; Sato, Nobuharu; Inaba, Makoto; Itagaki, Takashi

    2008-01-01

    During the last step of Active Test (AT) at Rokkasho Reprocessing Plant (RRP), the performance of the Separation Facility, mainly for pulsed columns and mixer-settlers were tested; Diluent washing efficiency, Plutonium extraction and stripping efficiency, Decontamination factors of fission products and Uranium and plutonium losses into wastes. Also, those of the Plutonium purification unit in the Purification Facility have been checked; Diluent washing efficiency, Plutonium extraction and stripping efficiency and Plutonium losses into wastes. Test results were equivalent to or better than expected values. (author)

  10. Active Test of Purification Facility at Rokkasho Reprocessing Plant

    International Nuclear Information System (INIS)

    Iseki, Tadahiro; Tsujimura, Akino; Nitta, Takeshi; Matsuda, Takashi

    2007-01-01

    During the second and third steps of Active Test of the Plutonium Purification unit, the extraction and reextraction performances of pulsed columns and mixer-settlers have been checked. Plutonium losses into wastes have been also checked. As a result, it was confirmed that the expected performances had been achieved. (authors)

  11. Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Abrao, A.; Franca, J.M. Jr.; Ikuta, A.; Pueschel, C.R.; Federgruen, L.; Lordello, A.R.; Tomida, E.K.; Moraes, S.; Brito, J. de; Gomes, R.P.; Araujo, J.A.; Floh, B.; Matsuda, H.T.

    1977-01-01

    This paper summarizes the main activities dealing with the fabrication of nuclear grade uranium and thorium compounds at the Instituto de Energia Atomica, Sao Paulo. Identification of problems and their resolutions, the experience gained in plant operation, the performance characteristics of an ion-exchange facility and a solvent extraction unit (a demonstration plant based on pulsed columns for purification of uranium and production of ammonium diuranate) are described. A moving-bed facility for UF 4 preparation and its operation is discussed. A pilot plant for uranium and thorium oxide microsphere preparation based on internal gelation for HTGR fuel type is also described. A solvent extraction pilot plant for thorium purification based on a compound extraction-scrubbing column and a mixer-settler battery and the involved technology for thorium purification are commented. The main products, namely ammonium diuranate, uranyl amonium tricarbonate, uranium trioxide, uranium tetrafluoride, thorium nitrate and thorium oxalate and their quality are commented. The development of necessary analytical procedures for the quality control of the mentioned nuclear grade products is summarized. A great majority of such procedures was particularly suitable for analyzing traces impurities. Designed for installation are the units for denitration of uranyl nitrate solutions and pilot plants for elemental fluorine and UF 6 . The installation of a laboratory-scale plant designed for reprocessing irradiated uranium and an experimental unit for the recovery of protactinium from irradiated thorium is in progress

  12. Impact of uranium-233/thorium cycle on advanced accountability concepts and fabrication facilities. Addendum 2 to application of advanced accountability concepts in mixed oxide fabrication

    International Nuclear Information System (INIS)

    Bastin, J.J.; Jump, M.J.; Lange, R.A.; Crandall, C.C.

    1977-11-01

    The Phase I study of the application of advanced accountability methods (DYMAC) in a uranium/plutonium mixed oxide facility was extended to cover the possible fabrication of uranium-233/thorium fuels. Revisions to Phase II of the DYMAC plan which would be necessitated by such a process are specified. These revisions include shielding requirements, measurement systems, licensing conditions, and safeguards considerations. The impact of the uranium/thorium cycle on a large-scale fuel fabrication facility was also reviewed; it was concluded that the essentially higher radioactivity of uranium/thorium feeds would lead to increased difficulties which tend to preclude early commercial application of the process. An amended schedule for Phase II is included

  13. Decisional tool to assess current and future process robustness in an antibody purification facility.

    Science.gov (United States)

    Stonier, Adam; Simaria, Ana Sofia; Smith, Martin; Farid, Suzanne S

    2012-07-01

    Increases in cell culture titers in existing facilities have prompted efforts to identify strategies that alleviate purification bottlenecks while controlling costs. This article describes the application of a database-driven dynamic simulation tool to identify optimal purification sizing strategies and visualize their robustness to future titer increases. The tool harnessed the benefits of MySQL to capture the process, business, and risk features of multiple purification options and better manage the large datasets required for uncertainty analysis and optimization. The database was linked to a discrete-event simulation engine so as to model the dynamic features of biopharmaceutical manufacture and impact of resource constraints. For a given titer, the tool performed brute force optimization so as to identify optimal purification sizing strategies that minimized the batch material cost while maintaining the schedule. The tool was applied to industrial case studies based on a platform monoclonal antibody purification process in a multisuite clinical scale manufacturing facility. The case studies assessed the robustness of optimal strategies to batch-to-batch titer variability and extended this to assess the long-term fit of the platform process as titers increase from 1 to 10 g/L, given a range of equipment sizes available to enable scale intensification efforts. Novel visualization plots consisting of multiple Pareto frontiers with tie-lines connecting the position of optimal configurations over a given titer range were constructed. These enabled rapid identification of robust purification configurations given titer fluctuations and the facility limit that the purification suites could handle in terms of the maximum titer and hence harvest load. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  14. The influence of tri-n-octyl phosphine oxide and extraction stage on purification of Thorium concentrate

    International Nuclear Information System (INIS)

    M-V-Purwani; Moch-Setyadji

    2015-01-01

    The extraction of thorium oxalate concentrate as processing product of monazite using Tri Octyl Phosphine Oxide (TOPO) has been done. The most impurities contained in thorium oxalate concentrate are Ce (cerium) and La (lanthanum). The purpose of this study is to purify Th by separating Ce and La using extraction process. The extraction is done by batch and multistage. The solution of feed or water phase is 10 grams of Th oxalate concentrate dissolved in 10.08 M HNO 3 so that the volume becomes 100 mL and the organic phase is TOPO in kerosene. Stripping in each stage conducted three times, first stripping use water, second stripping use 5 % oxalic acid and the third stripping use water. Extraction time at every stage is 15 minutes and stripping time at every stage is 5 minutes with ratio of aqueous phase to organic phase = 1 : 1 . The parameters were studied % TOPO - kerosene and number of extraction stage. The optimum usage of TOPO in kerosene is 5 %. On extraction I obtained Ce concentrate and on extraction II and III obtained Th concentrates. The extraction II efficiency of Th is 39.76 % and extraction III efficiency of Th is 26.33 % . Coefficient of distribution (Kd) of Th in stage II is 0.7587 and Kd of Th in stage III is 1.0096. Total extraction efficiency of Th is 80.08 %, total extraction efficiency of Ce is 56.12 %, and total extraction efficiency of La is 1.54 %. The separation factor of Th – Ce in extraction I is 1.00 and separation factor of Th – La in extraction I is 92.0, separation factor of Th – Ce in extraction II is 250.24, and separation factor of Th – La in extraction II is ∞. Separation factor of Th – Ce in extraction III is 124.22 and separation factor of Th – La in extraction III is ∞. Total separation factor of Th – Ce is 1.4270 and total separation factor of Th – La is 4.0459. The content of Th oxalate in stripping product from the extraction II is 97.06 % and in stripping product from the extraction III is 98

  15. Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Abrao, A.; Franca Junior, J.M.; Ikuta, A.

    1977-01-01

    The main activities developed at 'Instituto de Energia Atomica' Sao Paulo, Brazil, on the recovery of uranium from ores, the purification of uranium and thorium raw concentrates and their transformation in nuclear grade compounds, are reviewed. The design and assemble of pilot facilities for ammonium diuranate (ADV) uranium tetrafluoride, uranium trioxide, uranium oxide microspheres, uranyl nitrate denitration, uranim hexafluoride and thorium compounds are discussed. The establishment of analytical procedures are emphasized [pt

  16. Radiogenic lead from poly-metallic thorium ores as a valuable material for advanced nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, Gennady G.; Apse, Vladimir A.; Kulikov, Evgeny G.; Kozhahmet, Bauyrzhan K.; Shkodin, Alexey O.; Shmelev, Anatoly N.

    2017-03-15

    Main purpose of the study is assessing reasonability for recovery, production and application of radiogenic lead as a coolant, neutron moderator and neutron reflector in advanced fast reactors and accelerator-driven systems (ADS). The following results were obtained: 1. Radiogenic lead with high content of isotope {sup 208}Pb can be extracted from thorium or mixed thorium-uranium ores because {sup 208}Pb is a final product of {sup 232}Th natural decay chain. 2. The use of radiogenic lead with high {sup 208}Pb content in advanced fast reactors and ADS makes it possible to improve significantly their neutron-physical and thermal-hydraulic parameters. 3. The use of radiogenic lead with high {sup 208}Pb content in advanced fast reactors as a coolant opens the possibilities for more intense fuel breeding and for application of well-known oxide fuel instead of the promising but not tested enough nitride fuel under the same safety parameters. 4. The use of radiogenic lead with high {sup 208}Pb content in advanced fast reactors as a neutron reflector opens a possibility for substantial elongation of prompt neutron lifetime. As a result, chain fission reaction in the reactor core could be slowed down, and the reactor operation could become safer. 5. The use of radiogenic lead with high {sup 208}Pb content in ADS as a coolant can upgrade substantially the level of neutron flux in the ADS blanket. Thus, favorable conditions could be formed in the ADS blanket for effective transmutation of radioactive wastes with low cross-sections of radiative neutron capture.

  17. Uses of extraction and ion exchange chromatography in the thorium and rare earths separation from industrial residue generated in thorium purification unity at IPEN. Application of rare earths as catalysts for generation of hydrogen

    International Nuclear Information System (INIS)

    Zini, Josiane

    2010-01-01

    In the 70's a pilot plant for studies of different concentrates processing obtained from the chemical processing of monazite was operated at IPEN / CNEN-SP, with a view to obtaining thorium of nuclear purity. This unity was operated on an industrial scale since 1985, generating around 25 metric tons of residue and was closed in 2002. This waste containing thorium and rare earths was named Retoter (Rejeito de Torio e Terras Raras, in portuguese) and stored in the IPEN Safeguards shed. This paper studies the treatment of the waste, aimed at environmental, radiological and technology. Were studied two cases for the chromatographic separation of thorium from rare earths. One of them was the chromatographic extraction, where the extracting agent tributyl phosphate was supported on polymeric resins Amberlite XAD16. The other method is studied for comparison purposes, since the material used in chromatographic extraction is unprecedented with regard to the separation of thorium, was the ion-exchange chromatography using DOWEX 1-X8 strong cationic resin. Was studied also the chromatographic process of extraction with the extracting agent DEHPA supported on Amberlite XAD16 for the fractionation in groups of rare earths elements. Thorium was separated with high purity for strategic purposes and rare earths recovered free from thorium, were tested as a catalyst for ethanol reforming to hydrogen obtaining which is used in fuel cells for power generation. (author)

  18. Purification

    DEFF Research Database (Denmark)

    Andersen, Astrid Oberborbeck

    2017-01-01

    In Arequipa, Peru’s second largest city, engineers work hard to control water flows and provide different sectors with clean and sufficient water. In 2011, only 10 percent of the totality of water used daily by Arequipa’s then close to 1 million people—in households, tourism, industry, and mining......—was treated before it was returned to the river where it continues its flow downstream towards cultivated fields and, finally, into the Pacific Ocean. It takes specialized knowledge and manifold technologies to manage water and sustain life in Arequipa, and engineers are central actors for making water flow...... of categories can be understood as practices of purification. However, a purely technical grip on water is never possible. Unruly elements, like weather, contamination, urban dwellers, and competing interests, interfere and make processes of intervention unstable. Water is never completely cleaned, and, equally...

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

    International Nuclear Information System (INIS)

    Vijay, P.L.; Sehra, J.C.; Sundaram, C.V.; Gurumurthy, K.R.; Raghavan, R.V.

    1978-01-01

    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 MgCl 2 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 : O 2 - 847, N 2 - 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)

  20. Radiological significance of thorium processing in manufacturing

    International Nuclear Information System (INIS)

    Davis, M.W.

    1985-01-01

    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 Th 232 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

  1. Thorium utilization

    Energy Technology Data Exchange (ETDEWEB)

    Trauger, D B [Oak Ridge National Lab., TN (USA)

    1978-01-01

    Some of the factors that provide incentive for the utilization of thorium in specific reactor types are explored and the constraints that stand in the way are pointed out. The properties of thorium and derived fuels are discussed, and test and reactor operating experience is reviewed. In addition, symbiotic systems of breeder and converter reactor are suggested as being particularly attractive systems for energy production. Throughout the discussion, the High-Temperature Gas-Cooled Reactor and Molten Salt Reactor are treated in some detail because they have been developed primarily for use with thorium fuel cycles.

  2. Thorium research and development in Turkey

    International Nuclear Information System (INIS)

    Güngör, Görkem

    2015-01-01

    Turkey has a great potential regarding thorium resources. Thorium exploration activities have been done in the past mainly by state organizations for determining the thorium resources in Turkey. Thorium occurs as complex mineral together with barite, fluorite and rare earth elements (REE). The increase in global demand for REE creates the opportunity for REE production which will also produce thorium as a by-product. The development of nuclear energy program in Turkey provides the stimulus for research and development activities in nuclear technologies. The final declaration of the workshop emphasizes the importance of thorium reserves in Turkey and the necessity for thorium exploration and development activities in order to determine the feasibility of thorium mining and fuel cycle in Turkey. These activities should be conducted together with the development of technologies for separation of these complex minerals and purification of thorium, REE and other minerals to be utilized as commercial products. There are advanced academic research studies on thorium fuel cycle which should be supported by the industry in order to commercialize the results of these studies. Turkey should be integrated to international R and D activities on ADS which is expected to commercialize on medium term. The legislative framework should be developed in order to provide the industrial baseline for nuclear technologies independent from nuclear regulatory activities

  3. Guide to the conduct of public meetings as part of the public information process for uranium and thorium mine-mill facilities

    International Nuclear Information System (INIS)

    1980-01-01

    The Canadian Atomic Energy Control Board requires that an applicant for a site approval for a uranium or thorium mine-mill facility inform the public about the project and facilitate public response. For small undertakings, the information requirement may be met by a public meeting organized by the proponents of the project. This guide provides specific instructions on giving notice of the meeting, availability of documentation, choice of a chairperson, agenda, the roles of the proponents and the regulatory agencies, and means of obtaining feedback from the public. (L.L.)

  4. Thorium fuel cycle management

    International Nuclear Information System (INIS)

    Zajac, R.; Darilek, P.; Breza, J.; Necas, V.

    2010-01-01

    In this presentation author deals with the thorium fuel cycle management. Description of the thorium fuels and thorium fuel cycle benefits and challenges as well as thorium fuel calculations performed by the computer code HELIOS are presented.

  5. Uranium and thorium mining regulations: Amendments relating to financial assurances and decommissioning of uranium mining facilities. Consultative document

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, G L [Atomic Energy of Canada Ltd., Sheridan Park, ON (Canada). CANDU Operations

    1993-12-23

    The purpose of this document is to describe the objectives, scope, substance and application of proposed amendments to the Uranium and Thorium Mining Regulations; in particular, amendments relating to the provision of financial assurances for the decommissioning of Canadian uranium mines. (author).

  6. Uranium and thorium mining regulations: Amendments relating to financial assurances and decommissioning of uranium mining facilities. Consultative document

    International Nuclear Information System (INIS)

    Brooks, G.L.

    1993-01-01

    The purpose of this document is to describe the objectives, scope, substance and application of proposed amendments to the Uranium and Thorium Mining Regulations; in particular, amendments relating to the provision of financial assurances for the decommissioning of Canadian uranium mines. (author)

  7. Immobilized graphene-based composite from asphalt: Facile synthesis and application in water purification

    Energy Technology Data Exchange (ETDEWEB)

    Sreeprasad, Theruvakkattil Sreenivasan; Gupta, Soujit Sen [DST Unit on Nanoscience, Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India); Maliyekkal, Shihabudheen Mundampra [School of Mechanical and Building Sciences, VIT University, Chennai Campus, Chennai 600048 (India); Pradeep, Thalappil, E-mail: pradeep@iitm.ac.in [DST Unit on Nanoscience, Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-02-15

    Highlights: ► Facile strategy to make graphenic materials from cheaper precursor such as asphalt. ► Material can be made in solution; also as anchored on solid substrates. ► The synthesized material, GSC, was found to be excellent for water purification. ► The applicability was demonstrated through batch and laboratory columns experiments. ► The capacity was compared to other similar adsorbents and was found to be superior. -- Abstract: An in situ strategy for the preparation of graphene immobilized on sand using asphalt, a cheap carbon precursor is presented. The as-synthesized material was characterized in detail using various spectroscopic and microscopic techniques. The presence of G and D bands at 1578 cm{sup −1} and 1345 cm{sup −1} in Raman spectroscopy and the 2D sheet-like structure with wrinkles in transmission electron microscopy confirmed the formation of graphenic materials. In view of the potential applicability of supported graphenic materials in environmental application, the as-synthesized material was tested for purifying water. Removal of a dye (rhodamine-6G) and a pesticide (chlorpyrifos), two of the important types of pollutants of concern in water, were investigated in this study. Adsorption studies were conducted in batch mode as a function of time, particle size, and adsorbent dose. The continuous mode experiments were conducted in multiple cycles and they confirmed that the material can be used for water purification applications. The adsorption efficacy of the present adsorbent system was compared to other reported similar adsorbent systems and the results illustrated that the present materials are superior. The adsorbents were analyzed for post treatment and their reusability was evaluated.

  8. Utilization of BSS-Safety Series 115 in facilities for mining ore with uranium and thorium associated to it

    International Nuclear Information System (INIS)

    Matta, Luiz Ernesto S. de C.; Ferreira, Paulo R. Rocha; Mouco, Charles D. do C.L.

    1999-01-01

    During the year of 1995, the Brazilian Nuclear Energy Commission, started a investigation program called Mining Project. The main objective of this program was to create a integrated study of environmental and occupational conditions of mining ores with uranium and thorium associated to it. Several technical visits were done at four different types of mines: coal, phosphate, niobium and gold. This work presents the area monitoring results obtained by the occupational radiation protection group. The data found in these inspections were compared to limits established by national rules. A special assessment of the data obtained was done for a future adoption of the BSS-Safety Series 115 recommendations. (author)

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

    International Nuclear Information System (INIS)

    Wirkner, F.M.

    1979-01-01

    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 [pt

  10. Technology of getting of microspheric thorium dioxide

    International Nuclear Information System (INIS)

    Balakhonov, V.G.; Matyukha, V.A.; Saltan, N.P.; Filippov, E.A.; Zhiganov, A.N.

    1999-01-01

    There has been proposed a technique for getting granulated thorium dioxide from its salts solutions according to the cryogenic technology by the method of a solid phase conversion. It includes the following operations: dispersion of the initial solution into liquid nitrogen and getting of cryogranules of the necessary size by putting oscillations of definite frequency on a die device and by charging formed drops in the constant electric field; solid phase conversion of thorium salts into its hydroxide by treating cryogranules with a cooled ammonia solution, drying and calcination of hydroxide granules having got granulated thorium dioxide. At the pilot facility there have been defined and developed optimum regimes for getting granulated thorium dioxide. The mechanism of thorium hydroxide cryogranules conversion into thorium dioxide was investigated by the thermal analysis methods. (author)

  11. Equipment for the handling of thorium materials

    International Nuclear Information System (INIS)

    Heisler, S.W. Jr.; Mihalovich, G.S.

    1988-01-01

    The Feed Materials Production Center (FMPC) is the United States Department of Energy's storage facility for thorium. FMPC thorium handling and overpacking projects ensure the continued safe handling and storage of the thorium inventory until final disposition of the materials is determined and implemented. The handling and overpacking of the thorium materials requires the design of a system that utilizes remote handling and overpacking equipment not currently utilized at the FMPC in the handling of uranium materials. The use of remote equipment significantly reduces radiation exposure to personnel during the handling and overpacking efforts. The design system combines existing technologies from the nuclear industry, the materials processing and handling industry and the mining industry. The designed system consists of a modified fork lift truck for the transport of thorium containers, automated equipment for material identification and inventory control, and remote handling and overpacking equipment for material identification and inventory control, and remote handling and overpacking equipment for repackaging of the thorium materials

  12. Thorium Th

    International Nuclear Information System (INIS)

    Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

    1978-01-01

    The basic methods for extracting thorium from monazites and determining it photometrically and complexometrically are described. Monazite is decomposed by fusion with sodium peroxide, then thorium and the totality of lanthanides are precipitated in the form of oxalates. After the oxalates have been broken down, thorium is determined photometrically with the aid of arsenazo 1, quercetin of 1-2(-pyridylazo)-resorcin. It takes 25 to 30 minutes to photometrically determine Th in monazites with the aid of arsenazo 2 (error: 3 to 5%). Arsenazo 2 is recommended for analysis of monazites containing 20 to 30% of lanthanides. Arsenazo 3 permits determining Th in zircon and in Nb-containing materials. In this case, the determination is possible in strongly acidic solutions, the ratio of arsenazo 3 to Th being 7.5:1. Arsenazo 3 can also be used in determining trace amounts of Th (1x10 -5 to 1x10 -4 %) in rocks, as well as in extraction-photometric determination of Th traces. The dyed compound of Th with arsenazo 3 is extracted with isoamyl alcohol in the presence of diphenylguanidinium chloride and monochloroacetic acid. The method permits determining Th at 1:5x10 8 (0.002 g/ml) dilution. Also described is the iodate-complexometric method for determining Th

  13. Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 2): Development, characterization, and performance evaluation.

    Science.gov (United States)

    Sudeep Kumara, K; Sahoo, B K; Gaware, J J; Sapra, B K; Mayya, Y S; Karunakara, N

    2017-06-01

    Exposure due to thoron ( 220 Rn) gas and its decay products in a thorium fuel cycle facility handling thorium or 232 U/ 233 U mixture compounds is an important issue of radiological concern requiring control and mitigation. Adsorption in a flow-through charcoal bed offers an excellent method of alleviating the release of 220 Rn into occupational and public domain. In this paper, we present the design, development, and characterization of a Thoron Mitigation System (TMS) for industrial application. Systematic experiments were conducted in the TMS for examining the 220 Rn mitigation characteristics with respect to a host of parameters such as flow rate, pressure drop, charcoal grain size, charcoal mass and bed depth, water content, and heat of the carrier gas. An analysis of the experimental data shows that 220 Rn attenuation in a flow through charcoal bed is not exponential with respect to the residence time, L/U a (L: bed depth; U a : superficial velocity), but follows a power law behaviour, which can be attributed to the occurrence of large voids due to wall channeling in a flow through bed. The study demonstrates the regeneration of charcoal adsorption capacity degraded due to moisture adsorption, by hot air blowing technique. It is found that the mitigation factor (MF), which is the ratio of the inlet 220 Rn concentration (C in ) to the outlet 220 Rn concentration (C out ), of more than 10 4 for the TMS is easily achievable during continuous operation (>1000 h) at a flow rate of 40 L min -1 with negligible (evaluated for its long-term performance and overall effectiveness in mitigating 220 Rn levels in the workplace. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A facile TiO{sub 2}/PVDF composite membrane synthesis and their application in water purification

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei, E-mail: wei.zhang@unisa.edu.au; Zhang, Yiming; Fan, Rong; Lewis, Rosmala [University of South Australia, Centre for Water Management and Reuse (Australia)

    2016-01-15

    In this work, we have demonstrated a facile wet chemical method to synthesise TiO{sub 2}/PVDF composite membranes as alternative water purification method to traditional polymer-based membrane. For the first time, hydrothermally grown TiO{sub 2} nanofibers under alkali conditions were successfully inserted into PVDF membranes matrix. The structure, permeability and anti-fouling performance of as-prepared PVDF/TiO{sub 2} composite membranes were studied systematically. The TiO{sub 2}/PVDF composite membranes prepared in this work promise great potential uses in water purification applications as microfiltration membranes due to its excellent physical/chemical resistance, anti-fouling and mechanical properties.

  15. The water purification system for the low background counting test facility of the Borexino experiment at Gran Sasso

    International Nuclear Information System (INIS)

    Balata, M.; Cadonati, L.; Laubenstein, M.; Heusser, G.; Giammarchi, M.G.; Scardaoni, R.; Torri, V.; Cecchet, G.; De Bari, A.; Perotti, A.

    1996-01-01

    The Borexino experiment, for the study of solar neutrino physics, requires radiopurity at the level of 5 x 10 -16 g/g 238 U equivalent (or 6 x 10 -9 Bq/kg) on a detector mass of many tons of scintillator. Feasibility studies are performed in a counting test facility now operating at LNGS, which consists of 4 t of liquid scintillator viewed by 100 photomultipliers and shielded by 100 t of water. The accomplishment of this goal requires the shielding liquid, water, to be at the 10 -13 g/g contamination level (1.2 x 10 -6 Bq/kg) or better. This paper describes the water purification system; it consists of a combination of several purification processes to remove particulate, radioactive ions, dissolved gases and other impurities. Residual contaminations are measured by analytical or direct-counting techniques. For radon measurement, particularly challenging at this low activity levels, a low background counting method has been developed. (orig.)

  16. Thorium-232

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain; Vial, Eric

    2013-12-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with Thorium-232

  17. Review of thorium fuel reprocessing experience

    International Nuclear Information System (INIS)

    Brooksbank, R.E.; McDuffee, W.T.; Rainey, R.H.

    1978-01-01

    The review reveals that experience in the reprocessing of irradiated thorium materials is limited. Plants that have processed thorium-based fuels were not optimized for the operations. Previous demonstrations of several viable flowsheets provide a sound technological base for the development of optimum reprocessing methods and facilities. In addition to the resource benefit by using thorium, recent nonproliferation thrusts have rejuvenated an interest in thorium reprocessing. Extensive radiation is generated as the result of 232 U-contamination produced in the 233 U, resulting in the remote operation and fabrication operations and increased fuel cycle costs. Development of the denatured thorium flowsheet, which is currently of interest because of nonproliferation concerns, represents a difficult technological challenge

  18. Measurement of cross-sections of fission reactions induced by neutrons on actinides from the thorium cycle at n-TOF facility

    International Nuclear Information System (INIS)

    Ferrant, L.

    2005-09-01

    In the frame of innovating energy source system studies, thorium fuel cycle reactors are considered. Neutron induced fission cross section on such cycle involved actinides play a role in scenario studies. To feed them, data bases are built with experimental results and nuclear models. For some nuclei, they are not complete or in disagreement. In order to complete these data bases, we have built an original set up, consisting in an alternation of PPACs (Parallel Plate Avalanche Chamber) and ultra - thin targets, which we installed on n-TOF facility. We describe detectors, set up, and the particular care brought to target making and characterization. Fission products in coincidence are detected with precise time measurement and localization with delay line read out method. We contributed, within the n-TOF collaboration, to the CERN brand new intense spallation neutron source characterization, based on time of flight measurement, and we describe its characteristics and performances. We were able to measure such actinide fission cross sections as 232 Th, 234 U, 233 U, 237 Np, 209 Bi, and nat Pb relative to 235 U et 238 U standards, using an innovative acquisition system. We took advantage of the lame accessible energy field, from 0.7 eV to 1 GeV, combined with the excellent energy resolution in this field. Data treatment and analysis advancement are described to enlighten performance and limits of the obtained results. (author)

  19. Recovery of lead-208 radiogenic of residues of thorium with rare earth

    International Nuclear Information System (INIS)

    Ferreira, J.C.; Freitas, A.A. de; Seneda, J.A.F.; Carvalho, M.S. de; Abrao, A.

    2008-01-01

    In the middle of the years 1970 in IPEN, considerable work for the purification and conversion of uranium and thorium project, the production of thorium nitrate, a pilot scale from different compounds of Thorium was accomplished; This installation of thorium nitrate produced for national marketing, given the industry of incandescent lighting gas mangles.. The method used by this installation was the purification by solvent extraction with pulsed columns. The thorium was in the organic phase, which was reversed as of thorium nitrate with a high degree of purity. The aqueous phase of this chemical process, containing impurities, some not extracted thorium and virtually all rare earths was precipitated in the form of a hydroxide. This was called RETOTER hydroxide (residue of Thorium and Rare Earth). This residue containing thorium, rare earth and some impurities such as lead-208 product of the decay of thorium-232 were stored in the shed of safeguarding IPEN for further recovery of thorium and rare earth. In this work was studied the recovery of lead-208, nuclear material of interest, separating it by the technique of cementation , where it adds zinc metallic to an acid solution of RETOTER, holding up the lead on the surface of the metallic zinc. (author)

  20. Review of Brazilian activities related to the thorium fuel cycle and production of thorium compounds at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.; Freitas, Antonio A.; Mindrisz, Ana C.

    2013-01-01

    The Brazilian's interest in the nuclear utilization of thorium has started in the 50's as a consequence of the abundant occurrence of monazite sands. Since the sixties, IPEN-CNEN/SP has performed some developments related to the thorium fuel cycle. The production and purification of thorium compounds was carried out at IPEN for about 18 years and the main product was the thorium nitrate with high purity, having been produced over 170 metric tons of this material in the period, obtained through solvent extraction. The thorium nitrate was supplied to the domestic industry and used for gas portable lamps (Welsbach mantle). Although the thorium compounds produced have not been employed in the nuclear area, several studies were conducted. Therefore, those activities and the accumulated experience are of strategic importance, on one hand due to huge Brazilian thorium reserves, on the other hand by the resurgence of the interest of thorium for the Generation IV Advanced Reactors. This paper presents a review of the Brazilian research and development activities related to thorium technology. (author)

  1. Interpretation of thorium bioassay data

    International Nuclear Information System (INIS)

    Juliao, L.M.Q.C.; Azeredo, A.M.G.F.; Santos, M.S.; Melo, D.R.; Dantas, B.M.; Lipsztein, J.L.

    1994-01-01

    A comparison have been made between bioassay data of thorium-exposed workers from two different facilities. The first of these facilities is a monazite sand extraction plant. Isotopic equilibrium between 232 Th and 238 Th was not observed in excreta samples of these workers. The second facility is a gas mantle factory. An isotopic equilibrium between 232 Th and 228 Th was observed in extra samples. Whole body counter measurements have indicated a very low intake of thorium through inhalation. As the concentration of thorium in feces was very high it was concluded that the main pathway of entrance of the nuclide was ingestion, mainly via contamination through dirty hands. The comparison between the bioassay results of workers from the two facilities shows that the lack of Th isotopic equilibrium observed in the excretion from the workers at the monazite sand plant possibly occurred due to an additional Th intake by ingestion of contaminated fresh food. This is presumably because 228 Ra is more efficiently taken up from the soil by plants, in comparison to 228 Th or 232 Th, and subsequently, 228 Th grows in from its immediate parent, 228 Ra. (author) 5 refs.; 3 tabs

  2. Purification of inert gas circuits of nuclear power facilities from tritium and hydrogen

    International Nuclear Information System (INIS)

    Eichler, R.

    1985-08-01

    Removing hydrogen and tritium from the inert primary coolant of a high temperature reactor is very important in regard to the process heat disposition. In this work a gas purification for a high temperature module reactor was laid out constructionally and researched technically. This system removes the contamination of the primary circuit with the aid of chemical getter beds of Cer alloy particles. (orig./PW) [de

  3. Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 1): Development of theoretical models for design considerations.

    Science.gov (United States)

    Sahoo, B K; Sudeep Kumara, K; Karunakara, N; Gaware, J J; Sapra, B K; Mayya, Y S

    2017-06-01

    Regulating the environmental discharge of 220 Rn (historically known as thoron) and its decay products from thorium processing facilities is important for protection of environment and general public living in the vicinities. Activated charcoal provides an effective solution to this problem because of its high adsorption capacity to gaseous element like radon. In order to design and develop a charcoal based Thoron Mitigation System, a mathematical model has been developed in the present work for studying the 220 Rn transport and adsorption in a flow through charcoal bed and estimating the 220 Rn mitigation factor (MF) as a function of system and operating parameters. The model accounts for inter- and intra-grain diffusion, advection, radioactive decay and adsorption processes. Also, the effects of large void fluctuation and wall channeling on the mitigation factor have been included through a statistical model. Closed form solution has been provided for the MF in terms of adsorption coefficient, system dimensions, grain size, flow rate and void fluctuation exponent. It is shown that the delay effects due to intra grain diffusion plays a significant role thereby rendering external equilibrium assumptions unsuitable. Also, the application of the statistical model clearly demonstrates the transition from the exponential MF to a power-law form and shows how the occurrence of channels with low probability can lower mitigation factor by several orders of magnitude. As a part of aiding design, the model is further extended to optimise the bed dimensions in respect of pressure drop and MF. The application of the results for the design and development of a practically useful charcoal bed is discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Sulfur hexafluoride purification from mixtures with air: a process feasibility study for the Holifield Heavy Ion Research Facility

    International Nuclear Information System (INIS)

    Perona, J.J.

    1979-01-01

    A preliminary feasibility study was made for the purification of SF 6 vapor contaminated with air for application at the Holifield Heavy Ion Research Facility. Liquefaction appears to be a good way to recover about 90% of the SF 6 if it is badly contaminated (15% air), and even greater recovery will be possible for mixtures containing less air. Where liquefaction is insufficient alone, adsorption of SF 6 on activated carbon at -50 0 F looks promising. Two carbon beds each containing about 500 lb of carbon should be sufficient. The refrigeration system for liquefaction and adsorption would have a capacity of about 2 tons. As alternatives, the use of molecular sieves to trap out the air was investigated, but such a bed would require at least 15,000 lb of molecular sieves and very long cycle times. A large-scale desublimer was investigated and appears workable but would require some development work to permit design work to proceed with confidence

  5. Study of treatment of a thorium and rare earths residue by extraction chromatography

    International Nuclear Information System (INIS)

    Zini, Josiane; Abrao, Alcidio; Carvalho, Fatima Maria Sequeira de; Freitas, Antonio Alves de; Scapin, Marcos Antonio

    2005-01-01

    In the 70's was established at IPEN the project of a thorium compounds purification pilot plant that had the goal of fulfilling the nuclear technology purity standards. The used method was the purification by extraction with solvents in pulsed columns. The thorium remaining in the organic phase was back extracted as thorium nitrate with a high degree of purity. Impurities, thorium non-extracted and practically all rare earths in aqueous phase of this chemical process were precipitated as hydroxide, generating a product containing thorium and rare earths, that was denominated RETOTER (residue of thorium and rare earths). This residue was accumulated and today there are 25 (twenty-five) metric tons of this by product stored in the safeguard storage shed at IPEN that must to be treated due to the radiation of the thorium and mainly his daughters. The average composition of this residue is, 68% in thorium oxide (ThO 2 ), 5% in rare earths oxides (R 2 O 3 ), 0,3% in uranium oxide (U 3 O 8 ) and common impurities such as phosphorus, iron, titanium, lead and sodium. In this work a new method is presented for separation and purification of thorium from this residue, obtaining a concentrate with high degree of purity for nuclear and non-nuclear use. This process will contribute to establish a decreasing of residue volumes, to have a mind to the minimization of environmental impacts, the reduction of worker's exposition and reduction of the storage costs. In this process the separation and purification of uranium and thorium is done by chromatography extraction, being used polymeric resins, that are previously functionalized with organic solvent (extractor agent). The effluent of this process is a concentrate of rare earths that can be reprocessed in a subsequent fractionating for to obtaining the individual fractions. (author)

  6. Nuclear energy from thorium

    International Nuclear Information System (INIS)

    Coote, G.E.

    1977-06-01

    Relevant topics in nuclear and reactor physics are outlined. These include: the thorium decay series; generation of fissile from fertile nuclides, in particular U-233 from Th-232; the princiiples underlying thermal breeder reactors; the production of U-232 in thorium fuel and its important influence on nuclear safeguards and the recycling of U-233. Development work is continuing on several types of reactor which could utilise thorium; each of these is briefly described and its possible role is assessed. Other tipics covered include safety aspects of thorium oxide fuel, reprocessing, fabrication of recycle fuel and the possibility of denaturing U-233 by adding natural uranium. It is concluded that previoue arguments for development of the thorium cycle are still valid but those relating to non-proliferation of weapons may become even more compelling. (auth.)

  7. Biochemistry Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Biochemistry Facility provides expert services and consultation in biochemical enzyme assays and protein purification. The facility currently features 1) Liquid...

  8. IAEA Director General visits purification facility at Polish thermal power station

    International Nuclear Information System (INIS)

    2001-01-01

    On the occasion of his first visit to Poland, the Director General of the IAEA visited an industrial scale Electron Beam Demonstration facility constructed with IAEA assistance at the Pomorzany Electric Power Station near Szczecin. The facility uses an electron beam device to purify gas effluents from coal burning. By the addition of ammonia, the process permits the production of fertilizer as a by-product. This is an excellent example of how nuclear techniques can be used to reduce the emissions from conventional power plants. Experience gained will help to demonstrate the environmental effectiveness and economic competitiveness of this technology and serve to illustrate how the IAEA in cooperation with Member States can provide advanced nuclear technique to industrial companies

  9. Thorium Molten Salt Nuclear Energy Synergetic System (THORIMS-NES)

    International Nuclear Information System (INIS)

    Yoshioka, Ritsuo; Mitachi, Koshi

    2013-01-01

    The authors have been promoting nuclear energy technology based on thorium molten salt as Thorium Molten Salt Nuclear Energy Synergetic System (THORIMS-NES). This system is a combination of fission power reactor of Molten Salt Reactor (MSR), and Accelerator Molten Salt Breeder (AMSB) for production of fissile 233 U with connecting chemical processing facility. In this paper, concept of THORIMS-NES, advantages of thorium and molten salt recent MSR design results such as FUJI-U3 using 233 U fuel, FUJI-Pu, large sized super-FUJI, pilot plant miniFUJI, AMSB, and chemical processing facility are described. (author)

  10. A safe, effective, and facility compatible cleaning in place procedure for affinity resin in large-scale monoclonal antibody purification.

    Science.gov (United States)

    Wang, Lu; Dembecki, Jill; Jaffe, Neil E; O'Mara, Brian W; Cai, Hui; Sparks, Colleen N; Zhang, Jian; Laino, Sarah G; Russell, Reb J; Wang, Michelle

    2013-09-20

    Cleaning-in-place (CIP) for column chromatography plays an important role in therapeutic protein production. A robust and efficient CIP procedure ensures product quality, improves column life time and reduces the cost of the purification processes, particularly for those using expensive affinity resins, such as MabSelect protein A resin. Cleaning efficiency, resin compatibility, and facility compatibility are the three major aspects to consider in CIP process design. Cleaning MabSelect resin with 50mM sodium hydroxide (NaOH) along with 1M sodium chloride is one of the most popular cleaning procedures used in biopharmaceutical industries. However, high concentration sodium chloride is a leading cause of corrosion in the stainless steel containers used in large scale manufacture. Corroded containers may potentially introduce metal contaminants into purified drug products. Therefore, it is challenging to apply this cleaning procedure into commercial manufacturing due to facility compatibility and drug safety concerns. This paper reports a safe, effective and environmental and facility-friendly cleaning procedure that is suitable for large scale affinity chromatography. An alternative salt (sodium sulfate) is used to prevent the stainless steel corrosion caused by sodium chloride. Sodium hydroxide and salt concentrations were optimized using a high throughput screening approach to achieve the best combination of facility compatibility, cleaning efficiency and resin stability. Additionally, benzyl alcohol is applied to achieve more effective microbial control. Based on the findings, the recommended optimum cleaning strategy is cleaning MabSelect resin with 25 mM NaOH, 0.25 M Na2SO4 and 1% benzyl alcohol solution every cycle, followed by a more stringent cleaning using 50 mM NaOH with 0.25 M Na2SO4 and 1% benzyl alcohol at the end of each manufacturing campaign. A resin life cycle study using the MabSelect affinity resin demonstrates that the new cleaning strategy

  11. The thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.R.

    1977-01-01

    The utilization of the thorium fuel cycle has long since been considered attractive owing to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Rapidly increasing uranium prices, public reluctance for widespread Pu recycling and expected delays for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, problems associated with reprocessing and waste handling, particularly with re-fabrication by remote handling of 233 U, are certainly not appreciably more difficult than for Pu recycling. To divert from uranium as a nuclear energy source it seems worth while intensifying future efforts for closing the Th/ 233 U fuel cycle. HTGRs are particularly promising for economic application. However, further research and development activities should not concentrate on this reactor type alone. Light- and heavy-water-moderated reactors, and even future fast breeders, may just as well take advantage of a demonstrated thorium fuel cycle. (author)

  12. Thorium ore deposits

    International Nuclear Information System (INIS)

    Angelelli, Victorio.

    1984-01-01

    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.) [es

  13. Thorium fuel cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, K [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

    1980-07-01

    Systems analysis of the thorium cycle, a nuclear fuel cycle accomplished by using thorium, is reported in this paper. Following a brief review on the history of the thorium cycle development, analysis is made on the three functions of the thorium cycle; (1) auxiliary system of U-Pu cycle to save uranium consumption, (2) thermal breeder system to exert full capacity of the thorium resource, (3) symbiotic system to utilize special features of /sup 233/U and neutron sources. The effects of the thorium loading in LWR (Light Water Reactor), HWR (Heavy Water Reactor) and HTGR (High Temperature Gas-cooled Reactor) are considered for the function of auxiliary system of U-Pu cycle. Analysis is made to find how much uranium is saved by /sup 233/U recycling and how the decrease in Pu production influences the introduction of FBR (Fast Breeder Reactor). Study on thermal breeder system is carried out in the case of MSBR (Molten Salt Breeder Reactor). Under a certain amount of fissile material supply, the potential system expansion rate of MSBR, which is determined by fissile material balance, is superior to that of FBR because of the smaller specific fissile inventory of MSBR. For symbiotic system, three cases are treated; i) nuclear heat supply system using HTGR, ii) denatured fuel supply system for nonproliferation purpose, and iii) hybrid system utilizing neutron sources other than fission reactor.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

    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 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

  15. Thorium in nuclear fuel

    International Nuclear Information System (INIS)

    Stankevicius, Alejandro

    2012-01-01

    We revise the advantages and possible problems on the use of thorium as a nuclear fuel instead of uranium. The following aspects are considered: 1) In the world there are three times more thorium than uranium 2) In spite that thorium in his natural form it is not a fisil, under neutron irradiation, is possible to transform it to uranium 233, a fisil of a high quality. 3) His ceramic oxides properties are superior to uranium or plutonium oxides. 4) During the irradiation the U 233 due to n,2n reaction produce small quantities of U 232 and his decay daughters' bismuth 212 and thallium 208 witch are strong gamma source. In turn thorium 228 and uranium 232 became, in time anti-proliferate due to there radiation intensity. 5) As it is described in here and experiments done in several countries reactors PHWR can be adapted to the use of thorium as a fuel element 6) As a problem we should mentioned that the different steps in the process must be done under strong radiation shielding and using only automatized equipment s (author)

  16. Investigation of thorium hydroxotrifluoroacetates

    International Nuclear Information System (INIS)

    Andryushin, V.G.; Samatov, A.V.; Chuklinov, R.N.; Shmidt, V.S.

    1984-01-01

    The precipitation process of thorium hydroxotrifluoroacetates in the Th(NO 3 ) 4 -HNO 3 -CF 3 COOH-NH 4 OH-H 2 O system in the pH range from 0.1 to 8.6 at a 100 g/l thorium concentration in it has been investigated. The curve of the pH dependence of the main thorium salts solubility in the pH=4.4 range exhibits a local maximum, the position of the latter being in complete accordance with its earlier established relation to the parameter of the ligand anion nucleophility. The composition of isolated hydroxotrifluoroacetate hydrates corresponds to the generic formula Th(OH)sub(x)(CFsub(3)COO)sub(4-x)xnHsub(2)O, where 3.0 >= x >= 1.5, and n=1.0-6.0. The density of the crystals obtained is measured and the thermal stability is studied. It is established, that, for the thorium hydroxotrifluoroacetate hydrates, the same general regularities in the effect of degree of hydrolysis and hydration on the position of decomposition temperature effects and on the density of compounds hold, as has been previously found in studying thorium- and plutonium hydroxosalts

  17. ZIRCONIUM-CLADDING OF THORIUM

    Science.gov (United States)

    Beaver, R.J.

    1961-11-21

    A method of cladding thorium with zirconium is described. The quality of the bond achieved between thorium and zirconium by hot-rolling is improved by inserting and melting a thorium-zirconium alloy foil between the two materials prior to rolling. (AEC)

  18. Thorium utilization in power reactors

    International Nuclear Information System (INIS)

    Saraceno; Marcos.

    1978-10-01

    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) [es

  19. Measurement of cross-sections of fission reactions induced by neutrons on actinides from the thorium cycle at n-TOF facility; Mesures de sections efficaces de fission induite par neutrons sur des actinides du cycle du thorium a n-TOF

    Energy Technology Data Exchange (ETDEWEB)

    Ferrant, L

    2005-09-01

    In the frame of innovating energy source system studies, thorium fuel cycle reactors are considered. Neutron induced fission cross section on such cycle involved actinides play a role in scenario studies. To feed them, data bases are built with experimental results and nuclear models. For some nuclei, they are not complete or in disagreement. In order to complete these data bases, we have built an original set up, consisting in an alternation of PPACs (Parallel Plate Avalanche Chamber) and ultra - thin targets, which we installed on n-TOF facility. We describe detectors, set up, and the particular care brought to target making and characterization. Fission products in coincidence are detected with precise time measurement and localization with delay line read out method. We contributed, within the n-TOF collaboration, to the CERN brand new intense spallation neutron source characterization, based on time of flight measurement, and we describe its characteristics and performances. We were able to measure such actinide fission cross sections as {sup 232}Th, {sup 234}U, {sup 233}U, {sup 237}Np, {sup 209}Bi, and {sup nat}Pb relative to {sup 235}U et {sup 238}U standards, using an innovative acquisition system. We took advantage of the lame accessible energy field, from 0.7 eV to 1 GeV, combined with the excellent energy resolution in this field. Data treatment and analysis advancement are described to enlighten performance and limits of the obtained results. (author)

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

    International Nuclear Information System (INIS)

    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 235 U) startup fuels, first-recycle and equilibrium (denatured 233 U) thorium--uranium LWR fuels, and to recover the plutonium generated in the 238 U denaturant as well. 12 figures, 3 tables

  1. The thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.R.

    1977-01-01

    The utilization of the thorium fuel cycle has long since been considered attractive due to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Although the uranium ore as well as the separative work requirements are usually lower for any thorium-based fuel cycle in comparison to present uranium-plutonium fuel cycles of thermal water reactors, interest by nuclear industry has hitherto been marginal. Fast increasing uranium prices, public reluctance against widespread Pu-recycling and expected retardations for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, it could be learned in the meantime that problems associated with reprocessing and waste handling, but particularly with a remote refabrication of 233 U are certainly not appreciably more difficult than for Pu-recycling. This may not only be due to psychological constraints but be based upon technological as well as economical facts, which have been mostly neglected up till now. In order to diversify from uranium as a nuclear energy source it seems to be worthwhile to greatly intensify efforts in the future for closing the Th/ 233 U fuel cycle. HTGR's are particularly promising for economic application. However, further R and D activites should not be solely focussed on this reactor type alone. Light and heavy-water moderated reactors, as well as even fast breeders later on, may just as well take advantage of a demonstrated thorium fuel cycle. A summary is presented of the state-of-the-art of Th/ 233 U-recycling technology and the efforts still necessary to demonstrate this technology all the way through to its industrial application

  2. Transformation using peroxide of a crude thorium hydroxide in nitrate for mantle grade

    International Nuclear Information System (INIS)

    Freitas, Antonio Alves de; Carvalho, Fatima Maria Sequeira de; Ferreira, Joao Coutinho; Abrao, Alcidio

    2002-01-01

    An alternative process for the recovery and purification of thorium starting from a crude thorium hydroxide as the precursor is outlined in this paper. Its composition is 60.1% thorium oxide (ThO 2 ), 18.6% rare earth oxides (TR 2 O 3 ), and common impurities like silicium, iron, titanium, lead and sodium. This material was produced industrially from the monazite processing in Brazil and has been stocked since several years. The crude thorium hydroxide is treated with hot nitric acid and after the digestion and addition of floculant it is filtered for the separation of the insoluble fraction. Using this nitrate solution, the thorium peroxide is precipitated after adjustment of pH and controlled addition of hydrogen peroxide. The final thorium peroxide is dissolved with nitric acid and the resulting thorium nitrate is mantle grade quality. Rare earth elements are recovered from the thorium peroxide filtrate. The main process parameters for the peroxide precipitation, like pH and temperature and main the results are presented and discussed. (author)

  3. Hygienic study of barrier function of local water purification facilities in respect to chemical pollutants agrochemicals and surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Il' in, I E

    1984-08-01

    Contamination of water reservoirs is presently a multicomponent phenomenon because pesticides, fertilizers, petroleum products, dyes and surfactants may all be present in water. Efficiency of commonly-employed water purification methods was evaluated: sedimentation, chlorination, filtering, and its related effect or representative groups of agricultural chemicals. The most vulnerable link in the rural water purification system was the filtration; in presence of surfactants, the filtration effectiveness was reduced by 40-50%. The effectiveness of this hauling function of surfactants was related to chemical structure of the polluting compounds and to homologous characteristics of the detergents. The effectiveness of the precipitation of chemical impurities from polluted water depended on their solubility in water. 1 figure.

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

    International Nuclear Information System (INIS)

    Dory, A.B.

    1980-05-01

    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)

  5. Lattice dynamics of thorium

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, J [Agra Coll. (India). Dept. of Physics

    1977-03-01

    In the present work, a local model pseudopotential has been proposed to study the lattice dynamics of thorium. The model potential depends on the core and ionic radii, and accounts for the s-d-f hybridization effects in a phenomenological way. When this form of potential is applied to derive the photon dispersion curves of Th, sufficiently good agreement is found between the computed and experimental results.

  6. Thorium-230 contamination

    International Nuclear Information System (INIS)

    Noey, K.C.; Liedle, S.D.; Hickey, C.R.; Doane, R.W.

    1989-01-01

    The authors are currently performing radiological surveys on approximately ninety properties in the St. Louis, Missouri area as part of the U.S. Department of Energy's Formerly Utilized Sites Remedial Action Program. The properties involved are the St. Louis Airport Site, Latty Avenue Properties, St. Louis Downtown Site, Coldwater Creek, and the associated roads and vicinity properties. The primary radioactive contaminant on these properties is thorium-230. Since field instrumentation is not available to detect the presence of alpha-emitting contamination in soil, soil samples are being collected and sent to an analytical laboratory for analysis. Thorium-230 analysis is costly and time-consuming, and as a result, soil sample analysis results are not available to help direct the field sampling program. This paper provides discussion of the manner in which the properties became radioactively contaminated, followed by a discussion of the difficulties associated with the detection of thorium-230. Finally, new methodologies for detecting alpha-emitting radionuclides in the field are described

  7. Hydriding of metallic thorium

    International Nuclear Information System (INIS)

    Miyake, Masanobu; Katsura, Masahiro; Matsuki, Yuichi; Uno, Masayoshi

    1983-01-01

    Powdered thorium is usually prepared through a combination of hydriding and dehydriding processes of metallic thorium in massive form, in which the hydriding process consists of two steps: the formation of ThH 2 , and the formation of Th 4 H 15 . However, little has yet been known as to on what stage of hydriding process the pulverization takes place. It is found in the present study that the formation of Th 4 H 15 by the reaction of ThH 2 with H 2 is responsible for pulverization. Temperature of 70 deg C adopted in this work for the reaction of formation Th 4 H 15 seems to be much more effective for production of powdered thorium than 200 - 300 deg C in the literature. The pressure-composition-temperature relationships for Th-H system are determined at 200, 300, 350, and 800 deg C. From these results, a tentative equilibrium phase diagram for the Th-H system is proposed, attention being focused on the two-phase region of ThH 2 and Th 4 H 15 . Pulverization process is discussed in terms of the tentative phase diagram. (author)

  8. Thorium-applications and handling

    International Nuclear Information System (INIS)

    Reichelt, A.

    1993-01-01

    The most important aspects concerning the natural occurrence and extraction of thorium are presented the topics covered are: natural isotopes, occurence in minerals, thorium-activity-content of naturally occuring materials, the resulting radiation exposure, extraction of thorium from ores, time-dependent activity after separation. The sources of radiation exposure due to Thorium, caused by human activity, can be divided into two categories, namely, those in which thorium is deliberately added to (consumer) products in order to improve their usefullness, and those in which the thorium is present accidentally and unwanted due to the naturally occuring thorium in the material used in the manufacturing processes. Some examples of such products and substances will be presented and results about their specific thorium activity will be discussed. Experimental data from a currently running research programme, will be presented, and will include results concerning the radiation occupational exposure due to phosphate fertilizers, thorium impregnated gas mantles and the use of thoriated TIG-Electrodes in arc welding. (orig.) [de

  9. Radkowsky Thorium Fuel Project

    International Nuclear Information System (INIS)

    Todosow, Michael

    2006-01-01

    In the early/mid 1990's Prof. Alvin Radkowsky, former chief scientist of the U.S. Naval Reactors program, proposed an alternate fuel concept employing thorium-based fuel for use in existing/next generation pressurized water reactors (PWRs). The concept was based on the use of a 'seed-blanket-unit' (SBU) that was a one-for-one replacement for a standard PWR assembly with a uranium-based central 'driver' zone, surrounded by a 'blanket' zone containing uranium and thorium. Therefore, the SBU could be retrofit without significant modifications into existing/next generation PWRs. The objective was to improve the proliferation and waste characteristics of the current once-through fuel cycle. The objective of a series of projects funded by the Initiatives for Proliferation Prevention program of the U.S. Department of Energy (DOE-IPP) - BNL-T2-0074,a,b-RU 'Radkowsky Thorium Fuel (RTF) Concept' - was to explore the characteristics and potential of this concept. The work was performed under several BNL CRADAs (BNL-C-96-02 and BNL-C-98-15) with the Radkowsky Thorium Power Corp./Thorium Power Inc. and utilized the technical and experimental capabilities in the Former Soviet Union (FSU) to explore the potential of this concept for implementation in Russian pressurized water reactors (VVERs), and where possible, also generate data that could be used for design and licensing of the concept for Western PWRs. The Project in Russia was managed by the Russian Research Center-?'Kurchatov Institute' (RRC-KI), and included several institutes (e.g., PJSC 'Electrostal', NPO 'LUCH' (Podolsk), RIINM (Bochvar Institute), GAN RF (Gosatomnadzor), Kalininskaja NPP (VVER-1000)), and consisted of the following phases: Phase-1 ($550K/$275K to Russia): The objective was to perform an initial review of all aspects of the concept (design, performance, safety, implementation issues, cost, etc.) to confirm feasibility/viability and identify any 'show-stoppers'; Phase-2 ($600K/$300K to Russia

  10. U.S. leans toward denatured thorium cycle

    International Nuclear Information System (INIS)

    Smock, R.

    1977-01-01

    Denatured thorium appears to be the most promising among the nonproliferating alternatives to the plutonium cycle, which the Carter Administration is trying to cancel. Criteria for a better system include uranium utilization comparable to current light water reactors and minimal separation of fissile material into the waste stream. Comparisons with other systems conclude that thorium is preferable because it can lead to an acceptable fast breeder. The thorium cycle can be placed in energy centers for sensitive facilities and can also be introduced into ongoing light water systems. Reprocessing can be handled in the centers, where thorium can be mixed with plutonium for use in reactors within the center, while light water reactors operate on the outside. Any fuel leaving the center would be unsuitable for weapons. Later adaptation to in-center fast breeders will extend energy supplies, although a thorium breeder will be less efficient than a plutonium fast breeder. Denatured thorium is a technical answer to a complex political problem, but those in the nuclear industry see the U.S. goal of a nonproliferating fuel as futile in the light of world politics and breeder efforts in other countries

  11. The thorium fuel cycle in water-moderated reactor systems

    International Nuclear Information System (INIS)

    Critoph, E.

    1977-01-01

    Current interest in the thorium cycle, as an alternative to the uranium cycle, for water-moderated reactors is based on two attractive aspects of its use - the extension of uranium resources, and the related lower sensitivity of energy costs to uranium price. While most of the scientific basis required is already available, some engineering demonstrations are needed to provide better economic data for rational decisions. Thorium and uranium cycles are compared with regard to reactor characteristics and technology, fuel-cycle technology, economic parameters, fuel-cycle costs, and system characteristics. There appear to be no major feasibility problems associated with the use of thorium, although development is required in the areas of fuel testing and fuel management. The use of thorium cycles implies recycling the fuel, and the major uncertainties are in the associated costs. Experience in the design and operation of fuel reprocessing and active-fabrication facilities is required to estimate costs to the accuracy needed for adequately defining the range of conditions economically favourable to thorium cycles. In heavy-water reactors (HWRs) thorium cycles having uranium requirements at equilibrium ranging from zero to a quarter of those for the natural-uranium once-through cycle appear feasible. An ''inventory'' of uranium of between 1 and 2Mg/MW(e) is required for the transition to equilibrium. The cycles with the lowest uranium requirements compete with the others only at high uranium prices. Using thorium in light-water reactors, uranium requirements can be reduced by a factor of between two and three from the once-through uranium cycle. The light-water breeder reactor, promising zero uranium requirements at equilibrium, is being developed. Larger uranium inventories are required than for the HWRs. The lead time, from a decision to use thorium to significant impact on uranium utilization (compared to uranium cycle, recycling plutonium), is some two decades

  12. Thorium cycles and proliferation

    International Nuclear Information System (INIS)

    Lovins, A.B.

    1979-01-01

    This paper analyzes several prevalent misconceptions about nuclear fuel cycles that breed fissile uranium-233 from thorium. Its main conclusions are: U-233, despite the gamma radioactivity of associated isotopes, is a rather attractive material for making fission bombs, and is a credible material for subnational as well as national groups to use for this purpose; (2) pure thorium cycles, which in effect merely substitute U-233 for Pu, would take many decades and much U to establish, and offer no significant safeguards advantage over Pu, cycles; (3) denatured Th-U cycles, which dilute the U-233 with inert U-238 to a level not directly usable in bombs, are not an effective safeguard even against subnational bomb-making; (4) several other features of mixed Th-U cycles are rather unattractive from a safeguards point of view; (5) thus, Th cycles of any kind are not a technical fix for proliferation (national or subnational) and, though probably more safeguardable than Pu cycles, are less so than once-through U cycles that entail no reprocessing; (6) while thorium cycles have some potential technical advantages, including flexibility, they cannot provide major savings in nuclear fuel resources compared to simpler ways of saving neutrons and U; and (7) while advocates of nuclear power may find Th cycles worth exploring, such cycles do not differ fundamentally from U cycles in any of the respects--including safeguards and fuel resources--that are relevant to the broader nuclear debate, and should not be euphorically embraced as if they did

  13. Remarks on the thorium cycle

    International Nuclear Information System (INIS)

    Teller, E.

    1978-01-01

    The use of thorium and neutrons to make 233 U would provide energy for many thousands of years. Thorium is more abundant than uranium and 233 U is the best fissile material for thermal neutron reactors. Four approaches to the use of thorium are worth developing: heavy water moderated reactors with conversion ratios greater than 0.9, such as modified CANDU with lower cost of separating D 2 O and 235 U; molten salt breeder reactors, from which fission products and excess fuel may be continuously removed; fusion-fission hybrids that produce adequate tritium and excess neutrons for sustenance and 233 U production in a subcritical thorium 233 U blanket; and by fission-initiated thermo-nuclear explosions in cavities in salt beds one mile below the earth's surface, yielding 233 U from the excess neutrons and thorium and decontaminated steam for power production. (author)

  14. Thorium utilisation in thermal reactors

    International Nuclear Information System (INIS)

    Balakrishnan, K.

    1997-01-01

    It is now more or less accepted that the best way to use thorium is in thermal reactors. This is due to the fact that U233 is a good material in the thermal spectrum. Studies of different thorium cycles in various reactor concepts had been carried out in the early days of nuclear power. After three decades of neglect, the world is once again looking at thorium with some interest. We in India have been studying thorium cycles in most of the existing thermal reactor concepts, with greater emphasis on heavy water reactors. In this paper, we report some of the work done in India on different thorium cycles in the Indian pressurized heavy water reactor (PHWR), and also give a description of the design of the advanced heavy water reactor (AHWR). (author). 1 ref., 2 tabs., 5 figs

  15. Thorium inorganic gels

    International Nuclear Information System (INIS)

    Genet, M.; Brandel, V.

    1988-01-01

    The optimum pH and concentration values of thorium salts and oxoacids or oxoacid salts which lead to transparent and stable inorganic gels have been determined. The isotherm drying process of the gel at 50 0 C leads successively to a partly dehydrated gel, then, to the formation of an unusual liquid phase and, finally to a dry amorphous solid phase which is still transparent. This kind of transparent inorganic gels and amorphous phase can be used as matrices for spectroscopic studies [fr

  16. PRETREATING THORIUM FOR ELECTROPLATING

    Science.gov (United States)

    Beach, J.G.; Schaer, G.R.

    1959-07-28

    A method is presented for pretreating a thorium surface prior to electroplating the surface. The pretreatment steps of the invention comprise cleaning by vapor blasting the surface, anodically pickling in a 5 to 15% by volume aqueous hydrochloric acid bath with a current of 125 to 250 amp/sq ft for 3 to 5 min at room temperature, chemically pickling the surface in a 5 to 15% by volume of aqueous sulfuric acid for 3 to 5 min at room temperature, and rinsing the surface with water.

  17. Anticipated radiological impacts from the mining and milling of thorium for the nonproliferative fuels

    International Nuclear Information System (INIS)

    Meyer, H.R.; Till, J.E.

    1978-01-01

    Recent emphasis on proliferation-resistant fuel cycles utilizing thorium--uranium-233 fuels has necessitated evaluation of the potential radiological impact of mining and milling thorium ore. Therefore, an analysis has been completed of hypothetical mine-mill complexes using population and meteorological data representative of a thorium resource site in the Lemhi Pass area of Idaho/Montana, United States of America. Source terms for the site include thorium-232 decay chain radionuclides suspended as dusts and radon-220 and daughters initially released as gas. Fifty-year dose commitments to maximally exposed individuals of 2.4 mrem to total body, 9.5 mrem to bone, and 35 mrem to lungs are calculated to result from facility operation. Radium-228, thorium-228, thorium-232 and lead-212 (daughter of radon-220) are found to be the principal contributors to dose. General population doses for a 50-mile radius surrounding the facility are estimated to be 0.05 man-rem to total body, 0.1 man-rem to bone, and 0.7 man-rem to lungs. Generally speaking, the results of this study indicate that the radiological aspects of thorium mining and milling should pose no significant problems with regard to implementation of thorium fuel cycles

  18. Systematic study on Thorium fuel

    International Nuclear Information System (INIS)

    Shibata, Toshikazu; Kimura, Itsuro; Iwata, Shiro; Furuya, Hirotaka; Suzuki, Susumu.

    1988-01-01

    Introduced is the activities of the Joint Research Project Team on Thorium Fuel organized by mainly university researchers in Japan and supported by the Ministry of Education, Science and Culture for seven years since 1980. Four major groups were organized; (1) nuclear data, reactor physics and design, (2) nuclear fuel, (3) down stream and (4) biological effects of thorium. The first group covered measurements and analysis on nuclear data of thorium related nuclides, experiment and analysis on nuclear characteristics of thorium containing cores, basic engineering on a thorium molten salt reactor, and designs of several types of reactors. Fabrication and irradiation tests of thorium oxide fuel, and basic studies on new type thorium fuels (e.g. carbide and nitride) were studied by the second group. The third group covered the use of solutions in reprocessing of spent fuel, behavior of fission products, immobilization of high level radioactive waste, and continuous reprocessing for a molten salt reactor. The fourth group performed the trace study for patients who had been intravascularly injected with thorotrast for diagnosis of war injuries during the Second World War. (author)

  19. Facile and rapid DNA extraction and purification from food matrices using IFAST (immiscible filtration assisted by surface tension).

    Science.gov (United States)

    Strotman, Lindsay N; Lin, Guangyun; Berry, Scott M; Johnson, Eric A; Beebe, David J

    2012-09-07

    Extraction and purification of DNA is a prerequisite to detection and analytical techniques. While DNA sample preparation methods have improved over the last few decades, current methods are still time consuming and labor intensive. Here we demonstrate a technology termed IFAST (Immiscible Filtration Assisted by Surface Tension), that relies on immiscible phase filtration to reduce the time and effort required to purify DNA. IFAST replaces the multiple wash and centrifugation steps required by traditional DNA sample preparation methods with a single step. To operate, DNA from lysed cells is bound to paramagnetic particles (PMPs) and drawn through an immiscible fluid phase barrier (i.e. oil) by an external handheld magnet. Purified DNA is then eluted from the PMPs. Here, detection of Clostridium botulinum type A (BoNT/A) in food matrices (milk, orange juice), a bioterrorism concern, was used as a model system to establish IFAST's utility in detection assays. Data validated that the DNA purified by IFAST was functional as a qPCR template to amplify the bont/A gene. The sensitivity limit of IFAST was comparable to the commercially available Invitrogen ChargeSwitch® method. Notably, pathogen detection via IFAST required only 8.5 μL of sample and was accomplished in five-fold less time. The simplicity, rapidity and portability of IFAST offer significant advantages when compared to existing DNA sample preparation methods.

  20. Thorium oxalate solubility and morphology

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.; Hall, R.

    1981-10-01

    Thorium was used as a stand-in for studying the solubility and precipitation of neptunium and plutonium oxalates. Thorium oxalate solubility was determined over a range of 0.001 to 10.0 in the concentration parameter [H 2 C 2 O 4 ]/[HNO 3 ] 2 . Morphology of thorium oxide made from the oxalate precipitates was characterized by scanning electron microscopy. The different morphologies found for oxalate-lean and oxalate-rich precipitations were in agreement with predictions based on precipitation theory

  1. Thorium-based Molten Salt Reactor (TMSR) project in China

    International Nuclear Information System (INIS)

    Dai, Zhimin; Liu, Wei

    2013-01-01

    Making great efforts in development of nuclear energy is one of the long-term-plan in China's energy strategies. The advantages of Thorium-based nuclear energy are: rich resource in nature, less nuclear waste, low toxicity, nuclear non-proliferation and so on. Furthermore, China is a country with abundant thorium, thus it is necessary to develop the Thorium-based Molten Salt Reactor (TMSR) in China. Shanghai Institute of Applied Physics, Chinese Academy of Sciences (SINAP) had designed and constructed the first China's light-water reactor and developed a zero-power thorium-based molten salt reactor successfully in the early 1970s. The applied research project 'thorium molten salt reactor nuclear power system' by SINAP together with several other institutes had been accepted and granted by China government in 2011. The whole project has been divided into three stages: Firstly, built a 2 MW-zero-power high temperature solid molten salt reactor in 2015 and a 2 MW-zero-power high temperature liquid molten salt reactor in 2017. Secondly, in 2020 built a 10 MW high temperature liquid molten salt reactor. Thirdly, on the base of previous work, a 100 MW high temperature molten salt reactor should be achieving in 2030. After more than one years of efforts, a high quality scientific research team has been formed, which is able to design the molten salt reactor, the molten salt loop and related key equipment, the systems of molten salt preparation, purification and the radioactive gas removal. In the past one year, the initial physical design of high temperature molten salt reactor has been completed; the nuclear chemistry and radiation chemical laboratory has been built, a high temperature salt (HTS) loop and radioactive gas removal experiment device system have been successfully developed and constructed. Further, the preliminary study on reactor used carbon-carbon composite material has been investigated. (author)

  2. Sustainability: role of thorium

    International Nuclear Information System (INIS)

    Stigson, Bjorn Roland

    2015-01-01

    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

  3. A proposal for rational thorium utilization: thorims-nes

    International Nuclear Information System (INIS)

    Kurukawa, K.; Erbay, L. B.

    1997-01-01

    In this study, a globally applicable system depending on a new philosophy has been introduced for solving the problems connected with nuclear safety, ratio-waste, anti-nuclear proliferation and terrorism and public/institutional acceptance and economy. This rational thorium breeding fuel-cycle system named as THORIMS-NES (Thorium Molten- Salt Nuclear Energy Synergetics ) appears to be particularly promising and can be the way of nuclear power development. THORIMS-NES depends on three principles: I. Thorium utilization, II. Application of molten-fluoride fuel technology and III. Separation of fissile producing breeders and power producing reactors. Thorium fuel cycle has benefit on the reduction of trans-U elements and for recycling fuels produced by all kinds of military, research and industrial reactors. A system for the realization of THORIMS-NES has been introduced by the explanation of connections/relations between facilities. In this study, the status of countries/groups working on Th and Th fuel cycle has been summarized. Additionally, the resultant announcement of the International Conference on Thorium Molten Salt Reactor Development (8-11 April, 1997, Santa Monica) has been mentioned to present the cooperation of scientists and engineers for the realization of THORIMS-NES

  4. Comparison studies adsorption of thorium and uranium on pure clay minerals and local Malaysian soil sediments

    International Nuclear Information System (INIS)

    Syed, H.S.

    1999-01-01

    Adsorption studies of thorium and uranium radionuclides on 9 different pure clay minerals and 4 local Malaysian soil sediments were conducted. Solution containing dissolved thorium and uranium at pH 4.90 was prepared from concentrate sludges from a long term storage facility at a local mineral processing plant. The sludges are considered as low level radioactive wastes. The results indicated that the 9 clay minerals adsorbed more uranium than thorium at pH ranges from 3.74 to 5.74. Two local Malaysian soils were observed to adsorb relatively high concentration of both radionuclides at pH 3.79 to 3.91. The adsorption value 23.27 to 27.04 ppm for uranium and 33.1 to 50.18 ppm for thorium indicated that both soil sediments can be considered as potential enhanced barrier material for sites disposing conditioned wastes containing uranium and thorium. (author)

  5. Magellanic Clouds Cepheids: Thorium Abundances

    Directory of Open Access Journals (Sweden)

    Yeuncheol Jeong

    2018-03-01

    Full Text Available The analysis of the high-resolution spectra of 31 Magellanic Clouds Cepheid variables enabled the identification of thorium lines. The abundances of thorium were found with spectrum synthesis method. The calculated thorium abundances exhibit correlations with the abundances of other chemical elements and atmospheric parameters of the program stars. These correlations are similar for both Clouds. The correlations of iron abundances of thorium, europium, neodymium, and yttrium relative to the pulsational periods are different in the Large Magellanic Cloud (LMC and the Small Magellanic Cloud (SMC, namely the correlations are negative for LMC and positive or close to zero for SMC. One of the possible explanations can be the higher activity of nucleosynthesis in SMC with respect to LMC in the recent several hundred million years.

  6. Thorium nuclear fuel cycle technology

    International Nuclear Information System (INIS)

    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

  7. Verification study of thorium cross section in MVP calculation of thorium based fuel core using experimental data

    International Nuclear Information System (INIS)

    Mai, V. T.; Fujii, T.; Wada, K.; Kitada, T.; Takaki, N.; Yamaguchi, A.; Watanabe, H.; Unesaki, H.

    2012-01-01

    Considering the importance of thorium data and concerning about the accuracy of Th-232 cross section library, a series of experiments of thorium critical core carried out at KUCA facility of Kyoto Univ. Research Reactor Inst. have been analyzed. The core was composed of pure thorium plates and 93% enriched uranium plates, solid polyethylene moderator with hydro to U-235 ratio of 140 and Th-232 to U-235 ratio of 15.2. Calculations of the effective multiplication factor, control rod worth, reactivity worth of Th plates have been conducted by MVP code using JENDL-4.0 library [1]. At the experiment site, after achieving the critical state with 51 fuel rods inserted inside the reactor, the measurements of the reactivity worth of control rod and thorium sample are carried out. By comparing with the experimental data, the calculation overestimates the effective multiplication factor about 0.90%. Reactivity worth of the control rods evaluation using MVP is acceptable with the maximum discrepancy about the statistical error of the measured data. The calculated results agree to the measurement ones within the difference range of 3.1% for the reactivity worth of one Th plate. From this investigation, further experiments and research on Th-232 cross section library need to be conducted to provide more reliable data for thorium based fuel core design and safety calculation. (authors)

  8. 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.

  9. Radiation protection procedures for the dismantling and decontamination of nuclear facility

    International Nuclear Information System (INIS)

    Almeida, C.C.; Garcia, R.H.L.; Cambises, P.B.S.; Silva, T.M. da; Paiva, J.E.; Carneiro, J.C.G.G.; Rodrigues, D.L.

    2013-01-01

    This work presents the operational procedures and conditions to ensure the required level of protection and safety during the dismantling and decontamination of a natural uranium purification facility at IPEN-CNEN/SP, Brazil. The facility was designed for chemical processing of natural uranium, aiming to obtain the uranyl nitrate, nuclear-grade. Afterwards, the installation operated in treatment and washing of thorium sulfate and thorium oxycarbonate dissolution, to get thorium nitrate as final product. A global evaluation of the potential exposure situation was carried out by radioprotection team in order to carry out the operations planned. For the facility dismantling, was established both measures to control the radiation exposure at workplace and individual monitoring of workers. A combination of physical, chemical and mechanical methods was used in the decontamination procedure applied in this unit. Concerning the internal operation procedures of IPEN-CNEN/SP, the radioactive waste control, the transport of the radioactive materials and authorization of use of decontaminated equipment were also subject of study. (author)

  10. Spectrographic determination of some rare earths in thorium compounds

    International Nuclear Information System (INIS)

    Brito, J. de.

    1977-01-01

    A method for spectrographic determination of Gd, Sm, Dy, Eu, Y, Yb, Tm and Lu in thorium compounds has been developed. Sensibilities of 0.01 μg rare earths/g Th02 were achieved. The rare earth elements were chromatographycally separated in a nitric acid-ether-cellulose system. The solvent mixture was prepared by dissolving 11% of concentrated nitric acid in ether. The method is based upon the sorption of the rare earths on activated cellulose, the elements being eluted together with 0.01 M HNO 3 . The retention of the 152 , 154 Eu used as tracer was 99,4%. The other elements showed recoveries varying from 95 to 99%. A direct carrier destillation procedure for the spectrochemical determination of the mentioned elements was used. Several concentrations of silver chloride were used to study the volatility behavior of the rare earths. 2%AgCl was added to the matrix as definite carrier, being lantanum selected as internal standard. The average coefficient of variation for this method was +- -+ 7%. The method has been appleid to the analysis of rare earths in thorium coumpounds prepared by Thorium Purification Pilot Plant at Atomic Energy Institute, Sao Paulo [pt

  11. Uranium hexafluoride purification

    International Nuclear Information System (INIS)

    Araujo, Eneas F. de

    1986-01-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF 6 -HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF 6 -HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  12. Drying characteristics of thorium fuel corrosion products

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.-E. E-mail: rzl@inel.gov

    2004-07-01

    The open literature and accessible US Department of Energy-sponsored reports were reviewed for the dehydration and rehydration characteristics of potential corrosion products from thorium metal and thorium oxide nuclear fuels. Mixed oxides were not specifically examined unless data were given for performance of mixed thorium-uranium fuels. Thorium metal generally corrodes to thorium oxide. Physisorbed water is readily removed by heating to approximately 200 deg. C. Complete removal of chemisorbed water requires heating above 1000 deg. C. Thorium oxide adsorbs water well in excess of the amount needed to cover the oxide surface by chemisorption. The adsorption of water appears to be a surface phenomenon; it does not lead to bulk conversion of the solid oxide to the hydroxide. Adsorptive capacity depends on both the specific surface area and the porosity of the thorium oxide. Heat treatment by calcination or sintering reduces the adsorption capacity substantially from the thorium oxide produced by metal corrosion.

  13. 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 ...

  14. Recovery of valuable products from the raffinate of uranium and thorium pilot-plant

    International Nuclear Information System (INIS)

    Martins, E.A.J.

    1990-01-01

    IPEN-CNEN/SP has being very active in refining yellow cake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, uranium tetra-and hexa-fluoride in sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major waste to be worked is the raffinate from purification via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid, ammonium nitrate, uranium, thorium and rare earth elements. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium-free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximize the recycle and reuse of the above mentioned chemicals. (author)

  15. The economics of thorium fuel cycles

    International Nuclear Information System (INIS)

    James, R.A.

    1978-01-01

    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)

  16. Use of thorium in the generation IV Molten Salt reactors and perspectives for Brazil

    International Nuclear Information System (INIS)

    Seneda, Jose A.; Lainetti, Paulo E.O.

    2013-01-01

    reactor and the experience of the IPEN in the purification of thorium compounds. (author)

  17. Use of thorium in the generation IV Molten Salt reactors and perspectives for Brazil

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

    characteristics of the molten salt reactor and the experience of the IPEN in the purification of thorium compounds. (author)

  18. Determination of sulfate in thorium salts using gravimetric technique with previous thorium separation

    International Nuclear Information System (INIS)

    Silva, C.M. da; Pires, M.A.F.

    1994-01-01

    Available as short communication only. A simple analytical method to analyze sulfates in thorium salt, is presented. The method is based on the thorium separation as hydroxide. The gravimetric technique is used to analyze the sulfate in the filtered as barium sulfate. Using this method, the sulfate separation from thorium has been reach 99,9% yield, and 0,1% precision. This method is applied to thorium salts specifically thorium sulfate, carbonate and nitrate. (author). 5 refs, 2 tabs

  19. Hodgkin's disease following thorium dioxide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Gotlieb, A I; Kirk, M E [McGill Univ., Montreal, Quebec (Canada). Dept. of Pathology; Hutchison, J L [Montreal General Hospital, Quebec (Canada)

    1976-09-04

    Hodgkin's disease occurred in a 53-year-old man who, 25 years previously, had undergone cerebral angiography, for which thorium dioxide suspension (Thorotrast) was used. Deposits of thorium dioxide were noted in reticuloendothelial cells in various locations. An association between thorium dioxide administration and the subsequent development of malignant tumours and neoplastic hematologic disorders has previously been reported.

  20. Advanced thorium cycles in LWRs and HWRs

    International Nuclear Information System (INIS)

    Radkowsky, A.

    The main aspects of advanced thorium cycles in LWRs and HWRs are reviewed. New concepts include the seed blanket close packed heavy water breeder, the light water seed blanket thorium burner and self-induced thorium cycle in CANDU type reactors. (author)

  1. Determination of natural thorium in urines

    International Nuclear Information System (INIS)

    Jeanmaire, L.; Jammet, H.

    1959-01-01

    A procedure for the quantitative analysis of thorium in urine is described. After precipitation with ammonium hydroxide, dissolution of the precipitate, extraction at pH 4-4.2 with cupferron in chloroformic solution and mineralization, a colorimetric determination of thorium with thorin is performed. It is thus possible to detect about 2 γ of thorium in the sample. (author) [fr

  2. The importance of thorium in the context of the generation in advanced reactors and the IPEN's experience

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.; Mindrisz, Ana C.; Freitas, Antonio A.

    2011-01-01

    thorium compounds and IPEN accumulated since the 60's a wide experience in the purification of thorium, obtained primarily from the monazite processing. Studies were also conducted on obtaining nuclear fuel based on thorium, the reduction of ThF 4 to metallic thorium, neutronic studies and proposition of reactor concepts based on the element. It should also be recorded that there was at IPEN, during this period, the production in pilot scale of over one hundred and seventy metric tons of thorium nitrate with high purity. In this paper, we present briefly the experience accumulated at IPEN-CNEN/SP-Brazil and the different areas that comprise the Thorium Fuel Cycle, and the possibilities and advantages of thorium use in the IV Generation Advanced Reactors. (author)

  3. Extractive spectrophotometric determination of thorium

    International Nuclear Information System (INIS)

    Venkatesan, M.; Gopalakrishnan, V.; Ramanujam, A.; Nadkarni, M.N.

    1981-01-01

    An extractive spectrophotometric method has been standardized for the analysis of 0.2 to 1.6 milligrams of thorium present in nitric acid solutions. The method involves the extraction of thorium from nitric acid solutions into 0.5 M thenoyl trifluoro acetone (HTTA) in benzene and its direct estimation from the organic extract by spectrophotometry as Thoron colour complex. In this method, interference due to iron upto 5 milligrams can be suppressed by adding ascorbic acid in the ratio of 1:2 prior to HTTA extraction. Uranium(VI) does not interefere even when present in 2000 times the amount of thorium. Plutonium and cerium do not interfere at one milligram level whereas zirconium interferes in this method. The overall error variation and precision of this method has been determined to be +- 3.5%. (author)

  4. Research and development of thorium fuel cycle

    International Nuclear Information System (INIS)

    Oishi, Jun.

    1994-01-01

    Nuclear properties of thorium are summarized and present status of research and development of the use of thorium as nuclear fuel is reviewed. Thorium may be used for nuclear fuel in forms of metal, oxide, carbide and nitride independently, alloy with uranium or plutonium or mixture of the compound. Their use in reactors is described. The reprocessing of the spent oxide fuel in thorium fuel cycle is called the thorex process and similar to the purex process. A concept of a molten salt fuel reactor and chemical processing of the molten salt fuel are explained. The required future research on thorium fuel cycle is commented briefly. (T.H.)

  5. Thorium in occupationally exposed men

    International Nuclear Information System (INIS)

    Stehney, A. F.

    1999-01-01

    Higher than environmental levels of 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

  6. Toxicology of thorium cycle nuclides

    International Nuclear Information System (INIS)

    Ballou, J.E.

    1984-01-01

    The purpose of this project is to investigate the biological hazards associated with uranium-thorium breeder fuels and fuel recycle process solutions. Initial studies emphasize the metabolism and long-term biological effects of inhaled 233 U- 232 U nitrate and oxide fuel materials and of 231 Pa, a major, long-lived, radioactive waste product. 1 figure, 3 tables

  7. Recovery of thorium from monazite

    International Nuclear Information System (INIS)

    Karve, V.M.; Mukherjee, T.K.

    1997-01-01

    The process practised in the monazite processing plant involves caustic soda digestion of finely ground monazite followed by aqueous processing to recover mixed rare earth chloride solution, thorium and uranium values in the form of hydroxide cake and tri sodium phosphate as a byproduct

  8. Some thorium fuel cycle strategies

    International Nuclear Information System (INIS)

    Duret, M.F.; Hatton, H.

    1979-02-01

    The report deals with the problem of introducing an advanced nuclear fuel cycle based on thorium in Canada. It is pointed out that timing and introduction rate are important considerations, certain choices of these variables leading to undesirable business fluctuations in some of the industries involved in the production of nuclear energy. (author)

  9. Thorium: Issues and prospects in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul [Nuclear Science Programme, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia. walareqi@yahoo.com (Malaysia)

    2015-04-29

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  10. Thorium: Issues and prospects in Malaysia

    International Nuclear Information System (INIS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul

    2015-01-01

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment

  11. Thorium: Issues and prospects in Malaysia

    Science.gov (United States)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul

    2015-04-01

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  12. Virginia ADS consortium - thorium utilization

    International Nuclear Information System (INIS)

    Myneni, Ganapati

    2015-01-01

    A Virginia ADS consortium, consisting of Virginia Universities (UVa, VCU, VT), Industry (Casting Analysis Corporation, GEM*STAR, MuPlus Inc.), Jefferson Lab and not-for-profit ISOHIM, has been organizing International Accelerator-Driven Sub-Critical Systems (ADS) and Thorium Utilization (ThU) workshops. The third workshop of this series was hosted by VCU in Richmond, Virginia, USA Oct 2014 with CBMM and IAEA sponsorship and was endorsed by International Thorium Energy Committee (IThEC), Geneva and Virginia Nuclear Energy Consortium Authority. In this presentation a brief summary of the successful 3 rd International ADS and ThU workshop proceedings and review the worldwide ADS plans and/or programs is given. Additionally, a report on new start-ups on Molten Salt Reactor (MSR) systems is presented. Further, a discussion on potential simplistic fertile 232 Th to fissile 233 U conversion is made

  13. Thorium fuel cycle - Potential benefits and challenges

    International Nuclear Information System (INIS)

    2005-05-01

    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

  14. Determination of dose equivalent and risk in thorium cycle

    International Nuclear Information System (INIS)

    Ney, C.L.V.N.

    1988-01-01

    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) [pt

  15. Radiation protection in thorium industry

    International Nuclear Information System (INIS)

    Moraes, A.

    1977-01-01

    The evaluation of radiation doses in a monazite processing plant (thorium production cycle) aiming to getting information on the exposure levels to beta and gamma radiation, is discussed. It is observed that, excluding places where monazite is stored,or during transportation, or in silos, or waste deposits, or in places where high activity materials are stored or treated, the externa exposure stay below the maximum pemissible limit. Some recommendations are made based on the results found and according to radiation protection standards

  16. Assessment of thorium and thoron decay products in air - thorium plant

    International Nuclear Information System (INIS)

    Dhandayutham, R.; Gohel, C.O.; Shetty, P.N.; Savant, P.B.; Rao, D.V.V.

    1977-01-01

    For the evaluation of radiation dose to the lungs in a thorium plant, it is necessary to estimate the concentration of thorium, thoron and its daughter products in air. Methods employed in estimating thorium and its decay products and 'working level' are presented. (M.G.B.)

  17. Minerals yearbook, 1991: Thorium. Annual report

    International Nuclear Information System (INIS)

    Hedrick, J.B.

    1992-10-01

    Domestic mine production data for thorium-bearing monazite are developed by the U.S. Bureau of Mines from a voluntary survey of U.S. operations entitled, 'Rare Earths, Thorium, and Scandium.' The one mine to which a survey form was sent responded, representing 100% of domestic production. Mine production data for thorium are withheld to avoid disclosing company proprietary data. Statistics on domestic thorium consumption are developed by surveying various processors and end users, evaluating import-export data, and analyzing Government stockpile shipments

  18. Inhalation exposures at a thorium refinery

    International Nuclear Information System (INIS)

    Mausner, L.F.

    1982-01-01

    There is a current interest in the metabolism and health effects of thorium due to its potential use in the 232 Th - 233 U nuclear fuel cycle. The airborne concentrations of thorium, thoron daughters and rare earths in a plant which produced thorium and rare earth chemicals from 1932 to 1973 were calculated from past records of alpha counting and air filter samples. This analysis showed that high airborne concentrations of 232 Th, 220 Rn, 212 Pb, 212 Bi and rare earth elements were sometimes reached during plant operations. Limited measurements on autopsy samples of former employees of the plant showed increased tissue concentrations of thorium and rare earths. (U.K.)

  19. Supercritical fluid extraction of uranium and thorium employing dialkyl amides

    International Nuclear Information System (INIS)

    Rao, Ankita; Kumar, Pradeep

    2014-01-01

    Extraction and purification of actinides from different matrices is of utmost importance to the nuclear industry. In recent decades, supercritical fluid extraction (SFE) has emerged as a promising alternative to solvent extraction owing to its inherent potential of minimization of liquid waste generation. N,N-dialkyl aliphatic amides have been proposed to be an alternative to TBP in the reprocessing of spent nuclear fuel due to several attractive features like innocuous nature of degradation products (mainly carboxylic acids/ amines), possibility of complete incineration of the used extractant leading to reduction in volume of secondary waste. Also, physico-chemical properties of this class of extractants can be tuned by the judicious choice of alkyl groups. In the present work, N,N-dialkyl aliphatic amides with varying alkyl groups viz. N,N-dibutyl-2-ethylhexanamide (DBEHA), N,N-dibutyl-3,3-dimethylbutanamide (DBDMBA), N,N-dihexyloctanamide (DHOA), N,N-disecbutylpentamide (DBPA), N,N-dibutyloctanamide (DBOA), have been evaluated for supercritical fluid extraction (SFE) of uranium and thorium from nitric acid medium as well as tissue paper matrix. Amides were obtained from Department of Chemistry, Delhi University and were used as such. This fact could be exploited for separation of thorium and uranium

  20. Neutron irradiation effects on the mechanical properties of thorium and thorium--carbon alloy

    International Nuclear Information System (INIS)

    Wang, S.C.P.

    1978-04-01

    The effects of neutron exposure to 3.0 x 10 18 neutrons/cm 2 on the mechanical properties of thorium and thorium-carbon alloy are described. Tensile measurements were done at six different test temperatures from 4 0 K to 503 0 K and at two strain rates. Thorium and thorium-carbon alloy are shown to display typical radiation hardening like other face-centered cubic metals. The yield drop phenomenon of the thorium-carbon alloy is unchanged after irradiation. The variation of shear stress and effective shear stress with test temperature was fitted to Seeger's and Fleischer's equations for irradiated and unirradiated thorium and thorium-carbon alloy. Neutron irradiation apparently contributes an athermal component to the yield strength. However, some thermal component is detected in the low temperature range. Strain-rate parameter is increased and activation volume is decreased slightly for both kinds of metal after irradiation

  1. The various sodium purification techniques

    International Nuclear Information System (INIS)

    Courouau, J.L.; Masse, F.; Rodriguez, G.; Latge, C.; Redon, B.

    1997-01-01

    In the framework of sodium waste treatment, the sodium purification phase plays an essential role in the chain of operations leading to the transformation of the active sodium, considered as waste, into a stable sodium salt. The objectives of the purification operations are: To keep a low impurity level, particularly a low concentration in oxygen and hydrogen, in order to allow its transfer to a processing plant, and in order to avoid risks of plugging and/or corrosion in sodium facilities; To reduce the sodium activity in order to limit the dose rate close to the facilities, and in order to reduce the activity of the liquid and gaseous effluents. After a recall of the different kind of impurities that can be present in sodium, and of the different purification methods that could be associated with, the following points are highlighted: (i) Oxygen and hydrogen purification needs, and presentation of some selection criteria for a purification unit adapted to a sodium processing plant, as well as 2 cold trap concepts that are in accordance with these criteria: PSICHOS and PIRAMIDE. (ii) Tritium reduction in a bulk of liquid sodium by swamping, isotopic exchange, or permeation throughout a membrane. (iii) Caesium trapping on carbonaceous matrix. The main matrices used at present are R.V.C. (Reticulated Vitreous Carbon) and Actitex/Pica products. Tests in the laboratory and on an experimental device have demonstrated the performances of these materials, which are able to reduce sodium activity in Cs 134 and Cs 137 to very low values. The sodium purification processes as regards to the hydrogen, oxygen and caesium, that are aimed at facilitating the subsequent treatment of sodium, are therefore mastered operations. Regarding the operations associated with the reduction of the tritium activity, the methods are in the process of being qualified, or to be qualified. (author)

  2. Possible types of breeders with thorium cycle

    International Nuclear Information System (INIS)

    Ishiguro, Y.; Gouveia, A.S. de

    1981-01-01

    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) [pt

  3. Possible types of breeders with thorium cycle

    International Nuclear Information System (INIS)

    Ishiguro, Y.; Gouveia, A.S. de.

    1981-02-01

    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) [pt

  4. Thorium resources and energy utilization (14)

    International Nuclear Information System (INIS)

    Unesaki, Hironobu

    2014-01-01

    After the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, thorium reactor has been attracting attention from the viewpoint of safety. Regarding thorium as the resources for nuclear energy, this paper explains its estimated reserves in the whole world and each country, its features such as the situation of utilization, and the reason why it attracts attention now. The following three items are taken up here as the typical issues among the latest topics on thorium: (1) utilization of thorium as a tension easing measure against environmental effects involved in nuclear energy utilization, (2) thorium-based reactor as the next generation type reactor with improved safety, and (3) thorium utilization as the improvement policy of nuclear proliferation resistance. The outline, validity, and problems of these items are explained. Thorium reactor has been adopted as a research theme since the 1950s up to now mainly in the U.S. However, it is not enough in the aspect of technological development and also insufficient in the verification of reliability based on technological demonstration, compared with uranium-fueled light-water reactor. This paper explains these situations, and discusses the points for thorium utilization and future prospects. (A.O.)

  5. Thorium and health: state of the art

    International Nuclear Information System (INIS)

    Leiterer, A.; Berard, Ph.; Menetrier, F.

    2010-01-01

    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)

  6. Production of thorium nitrate from uranothorianite ores

    International Nuclear Information System (INIS)

    Brodsky, M.; Sartorius, R.; Sousseuer, Y.

    1959-01-01

    The separation of thorium and uranium from uranothorianite ores, either by precipitation or solvent-extraction methods, are discussed, and an industrial process for the manufacture of thorium nitrate is described. Reprint of a paper published in 'Progress in Nuclear Energy' Series III, Vol. 2 - Process Chemistry, 1959, p. 68-76 [fr

  7. Interaction between thorium and potential clad materials

    International Nuclear Information System (INIS)

    Kale, G.B.; Gawde, P.S.; Sengupta, Pranesh

    2005-01-01

    Thorium based fuels are being used for nuclear reactors. The structural stability of fuel-clad assemblies in reactor systems depend upon the nature of interdiffusion reaction between fuel-cladding materials. Interdiffusion reaction thorium and various cladding materials is presented in this paper. (author)

  8. Homogeneous Thorium Fuel Cycles in Candu Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hyland, B.; Dyck, G.R.; Edwards, G.W.R.; Magill, M. [Chalk River Laboratories, Atomic Energy of Canada Limited (Canada)

    2009-06-15

    The CANDU{sup R} 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 [1]. These features facilitate the introduction and full exploitation of thorium fuel cycles in Candu reactors in an evolutionary fashion. Because thorium itself does not contain a fissile isotope, neutrons must be provided by adding a fissile material, either within or outside of the thorium-based fuel. Those same Candu features that provide fuel-cycle flexibility also make possible many thorium fuel-cycle options. Various thorium fuel cycles can be categorized by the type and geometry of the added fissile material. The simplest of these fuel cycles are based on homogeneous thorium fuel designs, where the fissile material is mixed uniformly with the fertile thorium. These fuel cycles can be competitive in resource utilization with the best uranium-based fuel cycles, while building up a 'mine' of U-233 in the spent fuel, for possible recycle in thermal reactors. When U-233 is recycled from the spent fuel, thorium-based fuel cycles in Candu reactors can provide substantial improvements in the efficiency of energy production from existing fissile resources. The fissile component driving the initial fuel could be enriched uranium, plutonium, or uranium-233. Many different thorium fuel cycle options have been studied at AECL [2,3]. This paper presents the results of recent homogeneous thorium fuel cycle calculations using plutonium and enriched uranium as driver fuels, with and without U-233 recycle. High and low burnup cases have been investigated for both the once-through and U-233 recycle cases. CANDU{sup R} is a registered trademark of Atomic Energy of Canada Limited (AECL). 1. Boczar, P.G. 'Candu Fuel-Cycle Vision', Presented at IAEA Technical Committee Meeting on 'Fuel Cycle Options for LWRs and HWRs', 1998 April 28 - May 01, also Atomic Energy

  9. Model Matematik Reduksi Thorium dalam Proses Elektrokoagulasi

    Directory of Open Access Journals (Sweden)

    Prayitno

    2017-11-01

    Full Text Available Thorium reduction by electrocoagulation has been conducted on radioactive waste with thorium contaminant grade of 5x10-4Kg/l through a batch system using aluminium electrodes. This study aims to determine a mathematical model of thorium reduction through speed reaction, constante reaction rate and reaction order which are affected by electrocoagulation process parameters like voltage, time, electrode distance, and pH. The research results the optimum voltage condition at 12.5 V at 1 cm electrode spacing, pH 7, and 30 minutes of processing time with 99.6 % efficiency. Prediction on thorium decline rate constante is obtained through mathematic integral method calculation. The research results thorium decline rate is following second order constante with its value at 5x10-3KgL-1min-1.

  10. Geochemical prospecting for thorium and uranium deposits

    International Nuclear Information System (INIS)

    Boyle, R.W.

    1982-01-01

    The basic purpose of this book is to present an analysis of the various geochemical methods applicable in the search for all types of thorium and uranium deposits. The general chemistry and geochemistry of thorium and uranium are briefly described in the opening chapter, and this is followed by a chapter on the deposits of the two elements with emphasis on their indicator (pathfinder) elements and on the primary and secondary dispersion characteristics of thorium and uranium in the vicinity of their deposits. The next seven chapters form the main part of the book and describe geochemical prospecting for thorium and uranium, stressing selection of areas in which to prospect, radiometric surveys, analytical geochemical surveys based on rocks (lithochemical surveys), unconsolidated materials (pedochemical surveys), natural waters and sediments (hydrochemical surveys), biological materials (biogeochemical surveys), gases (atmochemical surveys), and miscellaneous methods. A final brief chapter reviews radiometric and analytical methods for the detection and estimation of thorium and uranium. (Auth.)

  11. Utilization of thorium in thermal reactors

    International Nuclear Information System (INIS)

    Srinivasan, K.R.; Nakra, A.N.

    1978-01-01

    Large deposits of thorium are found in India. 233 U produced by neutron capture in 232 Th is a more valuable fuel for thermal reactors than the plutonium that results from capture in 238 U. These two facts are the main reasons for the interest in utilizing thorium in power reactors. But natural thorium does not contain any fissile material and its capture cross section is nearly two and a half times that of 238 U. These have made the fuelling cost high. However, in certain conditions and certain types of reactors the costs are comparable with those using uranium fuel. The relative cost effectiveness of different fuels is discussed. Apart from long term interest, the short term interest of using thorium fuel in RAPP type reactors is also briefly described. Finally the reactor physics experiments using thorium fuel and their comparison with calculations are presented. (author)

  12. Toxicity of thorium cycle nuclides

    International Nuclear Information System (INIS)

    Ballou, J.E.

    1986-01-01

    The purpose of this project is to investigate the biological hazards associated with uranium-thorium breeder fuels and fuel recycle process solutions. Initial studies emphasize the metabolism and long-term biological effects of inhaled 233 U- 232 U nitrate and oxide fuel materials and of 231 Pa, a major, long-lived, radioactive waste product. Rats were used as test animals. Dose-response relationships for malignant lung-tumor and bone-tumor induction after 232 UO 2 (NO 3 ) 2 inhalation are discussed. 2 figures, 1 table

  13. Recovery of valuable products in liquid effluents from uranium and thorium pilot units

    International Nuclear Information System (INIS)

    Jardim, E.A.; Abrao, A.

    1988-01-01

    IPEN-CNEN/SP has being very active in refining yellowcake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, uranium tetra- and hexafluoride in a sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major waste to be worked is the refinate from the solvent extraction column where uranium and thorium are purified via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid and ammonium nitrate. Distilled nitric acid and the final sulfuric acid as residue are recycle. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium-free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximise the recycle and reuse of the abovementioned chemicals. (author) [pt

  14. Recovery of valuable products in the raffinate of the uranium and thorium pilot-plant

    International Nuclear Information System (INIS)

    Jardim, E.A.; Abrao, A.

    1988-11-01

    IPEN-CNEN/SP has being very active in refining yellowcake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, tetra - and hexafluoride in a sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major to be worked is the raffinate from the solvent extraction colum where and thorium are purified via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid and ammonium nitrate. Distilled nitric acid and the final sulfuric acid as residue are recycle. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium - free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximize the recycle and reuse of the above mentioned chemicals. (author) [pt

  15. A novel HPLC method for separation of uranium from thorium using BEHSA modified semi preparative support

    International Nuclear Information System (INIS)

    Raju, Ch.Siva Kesava; Subramanian, M.S.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2006-01-01

    The determination of uranium and thorium is of great importance with respect to nuclear industry and environmental samples. High performance liquid chromatography (HPLC) has revolutionized as a powerful separation and analytical tool in the field of chemistry, biology, medicine, pharmacy, chemical technology, food science and many more. The major advantages of HPLC are its ability to provide rapid, high performance separations and extending the separations range from laboratory scale to preparative scale purification. HPLC became powerful technique for the separation of uranium and thorium. These methods were widely employed in applications such as separation of uranium from fission products and for the measurement of number of fissions as in the case of burn-up measurements on nuclear reactor fuels

  16. Thorium in heavy water reactors

    International Nuclear Information System (INIS)

    Andersson, G.

    1984-12-01

    Advanced heavy water reactors can provide energy on a global scale beyond the foreseeable future. Their economic and safety features are promising: 1. The theoretical feasibility of the Self Sufficient Equilibrium Thorium (SSET) concept is confirmed by new calculations. Calculations show that the adjuster rod geometry used in natural uranium CANDU reactors is adequate also for SSET if the absorption in the rods is graded. 2. New fuel bundle designs can permit substantially higher power output from a CANDU reactor. The capital cost for fuel, heavy water and mechanical equipment can thereby be greatly reduced. Progress is possible with the traditional fuel material oxide, but the use of thorium metal gives much larger effects. 3. A promising long range possibility is to use pressure tanks instead of pressure tubes. Heat removal from the core is facilitated. Negative temperature and void coefficients provide inherent safety features. Refuelling under power is no longer needed if control by moderator displacement is used. Reduced quality demand on the fuel permits lower fuel costs. The neutron economy is improved by the absence of pressure and clandria tubes and also by the use of radial and axial blankets. A modular seed blanket design can reduce the Pa losses. The experience from construction of tank designs is good e.g. AAgesta, Attucha. It is now also possible to utilize technology from LWR reactors and the implementation of advanced heavy water reactors would thus be easier than HTR or LMFBR systems. (Author)

  17. Construction and characterization of the TL/TH thorium calibration pads

    International Nuclear Information System (INIS)

    Steele, W.D.

    1987-09-01

    The Technical Measurements Center (TMC) was established and was tasked with developing and/or recommending measurement methods for use in support of remedial action programs. Since one aspect of this technical support is the provision of calibration facilities for standardization of field measurements, four sets of thorium-232 enriched pads (two pads per set) were constructed for use by remedial action contractors in calibrating portable field instruments that are used to make direct, in-situ measurements of radium-226, thorium-232, and potassium-40. This report presents the design, construction, and characterization data of the eight calibration pads. 17 refs., 8 figs., 15 tabs

  18. Determination of natural thorium in urines; Dosage du thorium dans les urines

    Energy Technology Data Exchange (ETDEWEB)

    Jeanmaire, L; Jammet, H [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    A procedure for the quantitative analysis of thorium in urine is described. After precipitation with ammonium hydroxide, dissolution of the precipitate, extraction at pH 4-4.2 with cupferron in chloroformic solution and mineralization, a colorimetric determination of thorium with thorin is performed. It is thus possible to detect about 2 {gamma} of thorium in the sample. (author) [French] Cet article decrit une technique de dosage du thorium dans l'urine. Apres precipitation par l'ammoniaque, remise en solution, extraction a pH 4-4,2 par le cupferron en solution chloroformique et mineralisation, le thorium est dose par colorimetrie avec le thorin. Cette methode permet de deceler environ 2 {gamma} de thorium dans l'echantillon. (auteur)

  19. Chemistry of titanium, zirconium and thorium picramates

    International Nuclear Information System (INIS)

    Srivastava, R.S.; Agrawal, S.P.; Bhargava, H.N.

    1976-01-01

    Picramates of titanium, zirconium and thorium are prepared by treating the aqueous sulphate, chloride and nitrate solutions with sodium picramate. Micro-analysis, colorimetry and spectrophotometry are used to establish the compositions (metal : ligand ratio) of these picramates as 1 : 2 (for titanium and zirconium) and 1 : 4 (for thorium). IR studies indicate H 2 N → Me coordination (where Me denotes the metal). A number of explosive properties of these picramates point to the fact that the zirconium picramate is thermally more stable than the picramates of titanium and thorium. (orig.) [de

  20. Purification of cerium, neodymium and gadolinium for low background experiments

    Directory of Open Access Journals (Sweden)

    Boiko R.S.

    2014-01-01

    Full Text Available Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search, 136Ce (2β+ candidate with one of the highest Q2β. The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  1. Synthesis of manganese oxides and antimony silicates and their applications to take up Thorium-234

    International Nuclear Information System (INIS)

    Al-Attar, L.; Budeir, Y.

    2009-07-01

    Birnessite, a layered manganese oxide, antimonysilicate and their corresponding cation-exchange derivatives were tested for their ability to take up thorium using a batch-type method. Sorption experiments were performed in different concentrations of acid, and sodium, potassium and calcium nitrate solutions in order to evaluate the influence of cations likely to be present in waste effluents. The results were expressed in terms of distribution coefficients. Linear regressions of the logarithmic plots enabled the elucidation of exchange mechanisms. Variation in the magnitude and mechanism of thorium sorption on the exchangers was ascribed to structural differences and the exchange properties of the materials, as well as the aqueous chemistry of the actinide element. The work expanded to included investigation of thorium solution' pH in controlling the sorption process. In nitric acid solutions, H-antimonysilicate proved to be the best sorbent. The hydrated layer structure of birnessite allows for facile mobility of the interlayer cations with fast kinetics and little structural rearrangement, making it of great importance for intercalation and ion exchange uses in salt conditions. Potassium had the most, and calcium the least, effect on thorium selectivity by birnessites, when they are present as macro components. Conversely, calcium ions did greatly inhibit the sorption behaviour of the actinide on Ca-doped antimonysilicate. Studying the effect of thorium solution' pH reflected the microcrystal modifications of birnessites occurred during experiments. (authors)

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

    International Nuclear Information System (INIS)

    Gunandjar

    2008-01-01

    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)

  3. New development of spectrophotometric analysis of thorium

    International Nuclear Information System (INIS)

    Yang Xiangzhen

    1992-01-01

    This review covers new development of spectrophotometric determination of thorium since 1980's. The methods include general spectrophotometry, double wavelength spectrophotometry, catalytic spectrophotometry, total differential spectrophotometry, derivative spectrophotometry and fluorescent spectrophotometry, etc

  4. Geochemical prospecting for uranium and thorium deposits

    International Nuclear Information System (INIS)

    Boyle, R.W.

    1980-01-01

    A brief review of analytical geochemical prospecting methods for uranium and thorium is given excluding radiometric techniques, except those utilized in the determination of radon. The indicator (pathfinder) elements useful in geochemical surveys are listed for each of the types of known uranium and thorium deposits; this is followed by sections on analytical geochemical surveys based on rocks (lithochemical surveys), unconsolidated materials (pedochemical surveys), natural waters and sediments (hydrochemical surveys), biological materials (biogeochemical surveys) and gases (atmochemical surveys). All of the analytical geochemical methods are applicable in prospecting for thorium and uranium, particularly where radiometric methods fail due to attenuation by overburden, water, deep leaching and so on. Efficiency in the discovery of uranium and/or thorium orebodies is promoted by an integrated methods approach employing geological pattern recognition in the localization of deposits, analytical geochemical surveys, and radiometric surveys. (author)

  5. Titanium(IV), zirconium, hafnium and thorium

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    Titanium can exist in solution in a number of oxidation states. The titanium(IV) exists in acidic solutions as the oxo-cation, TiO 2+ , rather than Ti 4+ . Zirconium is used in the ceramics industry and in nuclear industry as a cladding material in reactors where its reactivity towards hydrolysis reactions and precipitation of oxides may result in degradation of the cladding. In nature, hafnium is found together with zirconium and as a consequence of the contraction in ionic radii that occurs due to the 4f -electron shell, the ionic radius of hafnium is almost identical to that of zirconium. All isotopes of thorium are radioactive and, as a consequence of it being fertile, thorium is important in the nuclear fuel cycle. The polymeric hydrolysis species that have been reported for thorium are somewhat different to those identified for zirconium and hafnium, although thorium does form the Th 4 (OH) 8 8+ species.

  6. Thorium exposure in a niobium mine

    International Nuclear Information System (INIS)

    Fonseca, Adelaide M. Gondin da

    1995-01-01

    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

  7. The environmental behaviour of uranium and thorium

    International Nuclear Information System (INIS)

    Sheppard, M. I.

    1980-08-01

    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)

  8. Extraction of thorium from solution using tribenzylamine

    International Nuclear Information System (INIS)

    Whitehead, N.E.; Ditchburn, R.G.

    1975-01-01

    A method is described for isolating thorium from solutions in a state sufficiently pure for alpha spectroscopy. It parallels the method described by Moore and Thern (Radiochemical Radioanalytical Letters 19(2), 117-125, 1974), but uses tribenzylamine instead of Adogen 364. The method involves extracting thorium from a solution in 8M nitric acid, into a 6% w/v solution of tribenzylamine in toluene. The thorium is concentrated in a third, interfacial layer which forms. This layer is isolated, diluted with chloroform, and back extracted with 10M HC1. Overall yields range between 83 and 90% for one extraction. The acidic solution is taken down to near dryness, diluted until the pH is 2 and extracted into 1.2 ml of thenoyltrifluoroacetone in toluene. This solution is evaporated onto a stainless steel disk, flamed, and the disk may be used for alpha spectroscopy of thorium isotopes. (auth.)

  9. Polarographic determination of trace amounts of thorium

    Energy Technology Data Exchange (ETDEWEB)

    Zaofan Zhao; Xiaohua Cai; Peibiao Li; Handong Yang

    1986-07-01

    A sensitive linear-sweep polarographic method for the determination of thorium is described. It is based on the thorium complex with Xylidyl Blue I (XBI) in a medium containing ethylenediamine, 1, 10-phenanthroline, oxalic acid and ninhydrin, at pH 10.5-11.5. The complex has been proved to be Th(XBI)/sub 2/, with log ..beta..'=9.6. The method can be used to determine trace amounts of thorium over the range 3.5x10/sup -8/-3x10/sup -6/M. The detection limit is 1x10/sup -8/M. A solvent extraction procedure is necessary to eliminate interference from several cations. The method has been applied to determination of traces of thorium in minerals, with good results.

  10. Parametric study of a thorium model

    International Nuclear Information System (INIS)

    Lourenco, M.C.; Lipsztein, J.L.; Szwarcwald, C.L.

    2002-01-01

    Models for radionuclides distribution in the human body and dosimetry involve assumptions on the biokinetic behavior of the material among compartments representing organs and tissues in the body. One of the most important problem in biokinetic modeling is the assignment of transfer coefficients and biological half-lives to body compartments. In Brazil there are many areas of high natural radioactivity, where the population is chronically exposed to radionuclides of the thorium series. The uncertainties of the thorium biokinetic model are a major cause of uncertainty in the estimates of the committed dose equivalent of the population living in high background areas. The purpose of this study is to discuss the variability in the thorium activities accumulated in the body compartments in relation to the variations in the transfer coefficients and compartments biological half-lives of a thorium-recycling model for continuous exposure. Multiple regression analysis methods were applied to analyze the results. (author)

  11. Thorium and health: state of the art; Thorium et sante: etat de l'art

    Energy Technology Data Exchange (ETDEWEB)

    Leiterer, A.; Berard, Ph.; Menetrier, F.

    2010-07-01

    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)

  12. Transformation of thorium sulfate in thorium nitrate by ion exchange resin

    International Nuclear Information System (INIS)

    Pereira, W.

    1991-01-01

    A procedure for transforming thorium sulfate into thorium nitrate by means of a strong cationic ion exchanger is presented. The thorium sulfate solution (approximately 15 g/L Th (SO 4 ) 2 ) is percolate through the resin and the column is washed first with water, with a 0,2 M N H 4 OH solution and then with a 0.2 M N H 4 NO 3 solution in order to eliminate sulfate ion. Thorium is eluted with a 2 M solution of (N H 4 ) 2 CO 3 . This eluate is treated with a solution of nitric acid in order to obtain the complete transformation into Th (NO 3 ) 4 . The proposed procedure leads to good quality thorium nitrate with high uranium decontamination. (author)

  13. Plutonium metal burning facility

    International Nuclear Information System (INIS)

    Hausburg, D.E.; Leebl, R.G.

    1977-01-01

    A glove-box facility was designed to convert plutonium skull metal or unburned oxide to an oxide acceptable for plutonium recovery and purification. A discussion of the operation, safety aspects, and electrical schematics are included

  14. Obtaining a compound of thorium from national minerals, using hydrometallurgical techniques

    International Nuclear Information System (INIS)

    Oyarzun Vera, Rodrigo Alejandro

    2014-01-01

    This work presents a study done at the Chilean Nuclear Energy Commission emplacements (CCHEN), to obtain a thorium compound, coming from ores prospected in Chile. To do this, hydrometallurgical techniques were used, setting the operational conditions that, in future studies, will be optimized in order to improve the efficiency of the process involved in this labour. The ores selected for this study, were from prospects found in Chile's region III from the 70's to the 80's, under the project financed by the United Nations Development Program, UNDP, and the Chilean government. The tests involved are the followings: crushing and grinding, leaching, solvent extraction and precipitation, besides a calcination process, getting a ThO 2 compound at the end of the process. The best operational conditions in the leaching process were achieved using a 7 [M] HCl solution, 7 hours of leaching time, leaching reason of 1 and 90 o C, fineness less than 180 μ at a stirring speed of 500, reaching a 33.29% and 64.15% of thorium in solution for ores coming from 'La Cuarta' and 'Sierra Indiana', respectively. About the iron removal, an extraction using 20% D2EHPA and 10%v/v of Isodecanol in kerosene was done, followed by a stripping with 1% HNO 3 , lowering considerably the iron pull to the purification stage by solvent extraction in more than 80%. The purification process was used for Sierra Indiana solutions, due to their higher thorium contents, besides lower iron content. This stage was carried out using an organic phase of 0,5 M Cyanex®272 in kerosene at ambient temperature, doing a total of 6 extraction stages and 7 stripping stages, this last one using 2 [M] H 2 SO 4 solutions, obtaining a total recovery of 73.56% in extraction and 56.82% in stripping. The precipitation stage was done using NH 4 OH solutions, until reaching a pH value of 4.5, separating the thorium from the rare earth elements and the uranium. In the case of the iron

  15. Spallation symbiont and thorium breeding

    International Nuclear Information System (INIS)

    Furukawa, Kazuo

    1991-01-01

    The medium term world energy and environment countermeasures for 2020-2070 are not yet clearly established. The forecast of energy situation hereafter, its problems and the measures for solution are considered. World trend is removing borders, and the north-south problems are increasing the importance. The rational and clear idea with the support of concrete technology is required. The demand of energy will increase enormously at the annual rate of 2.3%. The world energy situation was forecast considering the increase of population, and it will be 115 TW at the end of the next century. The present status, problems and the countermeasures in nuclear fission energy technology are explained. The countermeasures should be based on three principles, namely Th-U-233 cycle, the utilization of molten fluoride fuel medium and the separation of molten salt breeders and molten salt reactors. Accelerator molten salt breeders, small molten salt reactors, the nuclear fuel cycle and the annihilation process for radioactive wastes are reported. The perspective that the nuclear energy system, in which the reactor safety, the measures to wastes and others are improved by the spallation-fission symbiont using thorium molten salt as the working medium, can be constructed is shown. (K.I.)

  16. Thorium research activities in Japan

    International Nuclear Information System (INIS)

    Sasa, Toshinobu

    2015-01-01

    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

  17. Investigation of quantitative separation of thorium, uranium, neptunium and plutonium from complex radiochemical mixtures

    International Nuclear Information System (INIS)

    Ushatskij, V.N.; Preobrazhenskaya, L.D.; Kolychev, V.B.; Gugel', E.S.

    1979-01-01

    Quantitative separation of actinides and their radiochemical purification with the aid of TBP with subsequent separation of thorium and quantitative separation of U, Np and Pu with the aid of D2EHPA have been studied. The method has been developed for quantitative extraction-chromatographic separation and radiochemical purification of nanogram amounts of U, Pu and microgram amounts of Th and Np from complex radiochemical mixtures containing both fragment radioisotopes and non-radioactive macrocomponents ( Fe,Al,Mg,Mn, Na and others). The method calls for application of one-extraction-chromatographic column with TBP and one column with D2EHPA. Thorium is separated at the first stage since it does not form complexes in a chloride solution during washing of the sorption column with 6. OM HCl. Npsup((4)) and Pusup((3)) required for separation are stabilized with the aid of hydrazine and hydroxylamine mixture. The yield of each of the above-cited actinide elements during the complete two-stage separation and at the stage of their separation varies within the range of 98.5-99.3%

  18. 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)

  19. Determination of boron spectrophotometry in thorium sulfate

    International Nuclear Information System (INIS)

    Federgrun, L.; Abrao, A.

    1976-01-01

    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 ThF 4 . To overcome this difficulty, the thorium sulfate is dissolved using a strong cationic ion exchanger, Th 4+ 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 [pt

  20. Moving towards sustainable thorium fuel cycles

    International Nuclear Information System (INIS)

    Hyland, B.; Hamilton, H.

    2011-01-01

    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 (ThO 2 ) based fuel offers both fuel performance and safety advantages over urania (UO 2 ) 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 UO 2 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)

  1. Measurement of thorium content in gas mantles produced in India

    Energy Technology Data Exchange (ETDEWEB)

    Gaur, P K [Bhabha Atomic Research Centre, Mumbai (India). Radiological Physics Div.; Chury, A J; Venkataraman, G [Bhabha Atomic Research Centre, Mumbai (India). Radiation Protection Services Div.

    1994-04-01

    Incandescent gas mantles, processed with thorium nitrate, were monitored for thorium content, using a 2 inch thick Nal(Tl) detector and detecting medium energy gamma radiations emitted by thorium daughters. Thirty different brands, manufactured in the country have been counted and most of them were found to contain thorium within the permissible limit specified by Atomic Energy Regulatory Board (AERB). (author). 5 refs., 1 fig., 3 tabs.

  2. Status and development of the thorium fuel cycle

    International Nuclear Information System (INIS)

    Yi Weijing; Wei Renjie

    2003-01-01

    A perspective view of the thorium fuel cycle is provided in this paper. The advantages and disadvantages of the thorium fuel cycle are given and the development of thorium fuel cycle in several types of reactors is introduced. The main difficulties in developing the thorium fuel cycle lie in the reprocessing and disposal of the waste and its economy, and the ways tried by foreign countries to solve the problems are presented in the paper

  3. Lessons learned at the Fernald thorium removal project

    International Nuclear Information System (INIS)

    Boyd, R.

    1990-01-01

    In 1987, IT Corporation was awarded a subcontract through Rust Engineering Co. to provide decontamination and decommissioning services at the US Department of Energy Feed Materials Production Center (FMPC) near Fernald, Ohio. The work included the removal and repackaging of approximately 8,000 cubic feet of thorium oxide from several structures, including a silo, elevated bins, bucket elevators, and the silo understructure. The removal and repackaging project was undertaken because the integrity of the containment structures was questionable. Rust and Westinghouse (the operating contractor at FMPC) also felt that the repackaging and warehousing of the thorium would reduce occupational radiation exposure to site workers. Worker safety and environmental protection being of primary importance, the removal work was performed within specially-designed radiological containment facilities. The project presented challenges which, according to Westinghouse and Rust personnel, made it one of the most hazardous projects ever attempted at Fernald. Challenges included relations between non-union and union personnel, a strike by craft labor, interactions among DOE, EPA, and Westinghouse and their impact on a fixed-price contract, the impact of hazardous waste regulations, safe operations, and the contamination-free release of materials

  4. Sorption of Uranium(VI and Thorium(IV by Jordanian Bentonite

    Directory of Open Access Journals (Sweden)

    Fawwaz I. Khalili

    2013-01-01

    Full Text Available Purification of raw bentonite was done to remove quartz. This includes mixing the raw bentonite with water and then centrifuge it at 750 rpm; this process is repeated until white purified bentonite is obtained. XRD, XRF, FTIR, and SEM techniques will be used for the characterization of purified bentonite. The sorption behavior of purified Jordanian bentonite towards and Th4+ metal ions in aqueous solutions was studied by batch experiment as a function of pH, contact time, temperature, and column techniques at 25.0∘C and . The highest rate of metal ions uptake was observed after 18 h of shaking, and the uptake has increased with increasing pH and reached a maximum at . Bentonite has shown high metal ion uptake capacity toward uranium(VI than thorium(IV. Sorption data were evaluated according to the pseudo- second-order reaction kinetic. Sorption isotherms were studied at temperatures 25.0∘C, 35.0∘C, and 45.0∘C. The Langmuir, Freundlich, and Dubinin-Radushkevich (D-R sorption models equations were applied and the proper constants were derived. It was found that the sorption process is enthalpy driven for uranium(VI and thorium(IV. Recovery of uranium(VI and thorium(IV ions after sorption was carried out by treatment of the loaded bentonite with different concentrations of HNO3 1.0 M, 0.5 M, 0.1 M, and 0.01 M. The best percent recovery for uranium(VI and thorium(IV was obtained when 1.0 M HNO3 was used.

  5. Alpha spectrometry and secondary ion mass spectrometry of thorium

    International Nuclear Information System (INIS)

    Strisovska, Jana; Kuruc, Jozef; Galanda, Dusan; Matel, Lubomir; Velic, Dusan; Aranyosiova, Monika

    2009-01-01

    A sample of thorium content on steel discs was prepared by electrodeposition with a view to determining the natural thorium isotope. Thorium was determined by alpha spectrometry and by secondary ion mass spectrometry and the results of the two methods were compared

  6. A survey of thorium utilization in thermal power reactors

    International Nuclear Information System (INIS)

    Oosterkamp, W.J.

    1974-01-01

    The present status of thorium utilization in thermal reactors HTGR's, HWR's and LWR's has been reviewed. Physics considerations are made to obtain the optimum use of thorium. Existing information on reprocessing and refabrication is given together with the properties of thorium metal and thoria

  7. Preparation of microcuries of 234-thorium

    International Nuclear Information System (INIS)

    Suner, A.; La Gamma de Batistoni, A.M.; Botbol, J.

    1974-11-01

    A procedure for the preparation of microcuries of 234 Th from hydrochloric acid solutions of uranium (VI) is described. A solution of uranyl chloride in radioactive equilibrium with 234 Th (older than 6 months) and having 232 Th as carrier, is percoled through a Dowex 50 Wx8 (H + ) resin bed, wherein is absorbed 85% of Th and some uranium, which is then desorbed with 10 N HCl. The thorium remains in the column and is extracted later with a 0,025 M SO 4 H 2 plus 1 M SO 4 (NH 4 ) 2 solution. The thorium solution is freed from sulfate by precipitation with ammonia, dissolving the precipitate with 10 N HCl, whose solution is treated with Dowex 2x8 resin. The ion exchanger absorbs the anionic impurities and the thorium obtained is of high chemical and radiochemical purity. (author)

  8. 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

  9. Reprocessing in the thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.

    1984-01-01

    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.) [de

  10. Determination of thorium 230Th in soils

    International Nuclear Information System (INIS)

    Alvarez, A.; Palomares, J.

    1988-01-01

    A method for the determination of 230 Th in environmental soils is described. Hydroxides formed, previous fusion with sodium peroxide are dissolved with HNO 3 8N. The thorium is coprecipitated with F 3 La and purified by anion exchange (AG 1x8 50-100 mesh). Thorium is electroplated onto a stainless steel disc, 230 Th is counted by alpha spectrometry and 234 Th used as a tracer by beta counting. The chemical yield for 1g of soil sample is 60-80%. Minimum detectable activities are about 2 mBq/g. (Author)

  11. Depth-Resolved Cathodoluminescence of Thorium Dioxide

    Science.gov (United States)

    2013-03-01

    plutonium-239 (239Pu)-based nuclear weapons. Thorium also results in less highly radioactive waste in comparison to the uranium fuels. Thorium is four...diameters (1/4 – 3/8”) (Mann & Thompson, 2010). The 99.99% ThO2 powder was placed into the ampoule with a basic mineralizer such as cesium fluoride...conversion ranging from 1 pA/V to 1 mA/V. The electrical noise is further reduced by cooling the PMT housing unit with liquid nitrogen as seen in

  12. Behavior of cationic, anionic and colloidal species of titanium, zirconium and thorium in presence of ion exchange resins

    International Nuclear Information System (INIS)

    Souza Filho, G. de; Abrao, A.

    1976-01-01

    The distribution of titanium, zirconium and thorium is aqueous and resin phases has been studied using strong cationic resin in the R-NH 4 form. Solutions of the above elements in perchloric, nitric, hydrochloric and suphuric media were used. Each set of experiments was made by separately varying one of the five parameters - type of anion present, acidity of solution, temperature of percolation, age of solution and concentration of the element. It was found that, depending on the particular balance of these parameters, the elements investigated may be found in acidic solutions either as cationic, anionic or colloidal species. It is emphasized that the colloidal species of titanium, zirconium or thorium are not retained by the ion exchangers, and from this property a method for the separation and purification of the above elements has been outlined [pt

  13. Technological assumptions for biogas purification.

    Science.gov (United States)

    Makareviciene, Violeta; Sendzikiene, Egle

    2015-01-01

    Biogas can be used in the engines of transport vehicles and blended into natural gas networks, but it also requires the removal of carbon dioxide, hydrogen sulphide, and moisture. Biogas purification process flow diagrams have been developed for a process enabling the use of a dolomite suspension, as well as for solutions obtained by the filtration of the suspension, to obtain biogas free of hydrogen sulphide and with a carbon dioxide content that does not exceed 2%. The cost of biogas purification was evaluated on the basis of data on biogas production capacity and biogas production cost obtained from local water treatment facilities. It has been found that, with the use of dolomite suspension, the cost of biogas purification is approximately six times lower than that in the case of using a chemical sorbent such as monoethanolamine. The results showed travelling costs using biogas purified by dolomite suspension are nearly 1.5 time lower than travelling costs using gasoline and slightly lower than travelling costs using mineral diesel fuel.

  14. Sor/88-243, 21 April 1988, uranium and thorium mining regulations

    International Nuclear Information System (INIS)

    1988-05-01

    These Regulations deal with radiological health and safety in uranium mining facilities and in effect, they formalise previous requirements imposed on such facilities through licence conditions. Licences are required for removing or excavating uranium or thorium; siting, constructing or operating a mine or a mill; and for decommissioning a mining facility. Applications for licences include technical conditions relevant to each type of activity concerned, the common condition being detailed descriptions of the activity, the radiation protection and environmental protection measures as well as the radiation monitoring programme [fr

  15. Uranium and thorium mining and milling: material security and risk assessment

    International Nuclear Information System (INIS)

    Steinhaeusler, F.; Zaitseva, L.

    2005-01-01

    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

  16. Competitive biosorption of thorium and uranium by Micrococcus luteus

    International Nuclear Information System (INIS)

    Nakajima, A.; Tsuruta, T.

    2004-01-01

    Eighteen species of bacteria were screened for abilities to adsorb thorium and uranium. High adsorption capacity was observed for thorium by Arthrobacter nicotianae and Micrococcus luteus, and for uranium by Arthrobacter nicotianae. The adsorption of both thorium and uranium by Micrococcus luteus cells was rapid, was affected by the solution pH, and obeyed the Langmuir adsorption isotherm for binary systems in a competitive manner taking the ionic charge of the metal ion into account. The thorium selectivity in the competitive adsorption is assumed to be caused by the faster adsorption and the slower desorption rates of thorium than those of uranium. (author)

  17. Retardation of uranium and thorium by a cementitious backfill developed for radioactive waste disposal.

    Science.gov (United States)

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Preedy, O; Read, D

    2017-07-01

    The solubility of uranium and thorium has been measured under the conditions anticipated in a cementitious, geological disposal facility for low and intermediate level radioactive waste. Similar solubilities were obtained for thorium in all media, comprising NaOH, Ca(OH) 2 and water equilibrated with a cement designed as repository backfill (NRVB, Nirex Reference Vault Backfill). In contrast, the solubility of U(VI) was one order of magnitude higher in NaOH than in the remaining solutions. The presence of cellulose degradation products (CDP) results in a comparable solubility increase for both elements. Extended X-ray Absorption Fine Structure (EXAFS) data suggest that the solubility-limiting phase for uranium corresponds to a becquerelite-type solid whereas thermodynamic modelling predicts a poorly crystalline, hydrated calcium uranate phase. The solubility-limiting phase for thorium was ThO 2 of intermediate crystallinity. No breakthrough of either uranium or thorium was observed in diffusion experiments involving NRVB after three years. Nevertheless, backscattering electron microscopy and microfocus X-ray fluorescence confirmed that uranium had penetrated about 40 μm into the cement, implying active diffusion governed by slow dissolution-precipitation kinetics. Precise identification of the uranium solid proved difficult, displaying characteristics of both calcium uranate and becquerelite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. A study of uranium-thorium mixed lattices; Etude de reseaux mixtes uranium - thorium

    Energy Technology Data Exchange (ETDEWEB)

    Bacher, P; Eckert, R; Mazancourt, R de [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Some subcritical experiments have been carried out during the charging of the pile G1 by introducing thorium bars in a regular lattice into the pile. The spreading out of these experiments over a period of three months has permitted: a) work on a pile gradually increasing in size and b) measurements on comparable charges in so far that they have either the same number of bars of thorium, or the same concentration of thorium. From the measurements at constant charge and at constant concentration, it is possible by extrapolation to determine the critical charges and concentrations. The values obtained have showed that the material Laplacian of the lattice depends linearly on the thorium concentration and must cancel out for a concentration T = 8.8 {+-} 0.3 per cent by volume. These results have been found, to a very good approximation, by a simple calculation. (author) [French] Des experiences sous-critiques ont ete effectuees au cours du chargement de la pile G1 en introduisant des barres de thorium reparties suivant un reseau regulier dans la pile. L'etalement de ces experiences sur trois mois a permis d'operer sur une pile de plus en plus grosse et de faire un grand nombre de mesures sur des chargements comparables par le fait qu'ils avaient soit le meme nombre de barres de thorium, soit la meme concentration en thorium. A partir des mesures a chargement constant et a concentration constante, il a ete possible de determiner par extrapolation les chargements et concentrations critiques. Les valeurs obtenues ont montre que le laplacien matiere moyen du reseau dependait lineairement de la concentration en thorium, et devrait s'annuler pour une concentration T = 8,8 {+-} 0,3% en volume. Ces resultats ont ete retrouves avec une tres bonne approximation par un calcul elementaire. (auteur)

  19. Cadmium purification with a vibrating reactor

    International Nuclear Information System (INIS)

    Torres, N.; Esna-Ashari, M.; Biallas, H.; Kangas, K.

    1986-01-01

    While electrolytically producing zinc from sulfide concentrates, purification is the most significant step. Impurities such as Co, Sn, Ge, Ni and Sb can cause extensive redissolution of the electrodeposited zinc, thus diminishing current efficiency. Other metals, particularly cadmium, lead and copper, can negatively affect zinc properties by deposition on the cathode. It is standard practice to use atomized zinc dust as a reducing agent in the purification process, either alone or combined with additives. In conventional operations, special facilities are necessary to produce zinc dust in an amount close to 8wt% of cathode production. This paper examines a technique which makes use of zinc granules instead of dust

  20. Thoron and associated risks in the handling of thorium compounds

    International Nuclear Information System (INIS)

    Pradel, J.; Billard, F.

    1959-01-01

    1. Thorium compounds continually give off thoron and its daughters and their radioactivity can constitute a danger for operators who may inhale them. 2. By analogy with radon the maximum admissible content in air of thoron and its daughters has been set at 10 -7 μc/cm 3 . However the differences in behaviour between radon and its active deposit on the one hand, and thoron and its daughters on the other, appear great enough to justify more thorough investigation. In fact it seemed probable that, contrary to what takes place with radon, the thoron + thorium A content at a given point may differ appreciable from the thorium B + thorium C + thorium C' + thorium C'' content at the same point, because of the considerable differences in half-life which allow a greater or lesser distribution. 3. To determine the relative concentrations it was necessary to develop a method for estimating thoron in equilibrium with thorium A, the measurement of thorium B and its daughters being carried out in the conventional way by counting the activity collected on a filter. 4. Another object of this study was to estimate the danger presented by thoron in equilibrium with thorium A in the immediate vicinity of thorium sources, in a plant extracting thorium from urano-thorianite. (author) [fr

  1. Future perspective of thorium based nuclear fuels and thorium potential of Turkey

    International Nuclear Information System (INIS)

    Unak, T.; Yildirim, Y.

    2001-01-01

    Today's nuclear technology has principally been based on the use of fissile U-235 and Pu-239. he existence of thorium in the nature and its potential use in the nuclear technology were not unfortunately into account with a sufficient importance. The global distributions of thorium and uranium reserves indicate that in general some developed countries such as the USA, Canada, Australia, France have considerable uranium reserves, and contrarily only some developing countries such as Turkey, Brazil, India, Egypt have considerable thorium reserves. The studies carried out on the thorium during the last 50 years have clearly showed that the thorium based nuclear fuels have the potential easily use in most of reactor types actually operated with the classical uranium based nuclear fuels without any considerable modification. In the case of the use of thorium based nuclear fuels in future nuclear energy production systems, the serious problems such as the excess of Pu-239, the proliferation potential of nuclear weapons, and also the anxious of nuclear terrorism will probably be resolved, and sustainable nuclear energy production will be realized in the next new century. (authors)

  2. Future perspective of thorium based nuclear fuels and thorium potential of Turkey

    International Nuclear Information System (INIS)

    Unak, T.; Yildirim, Y.

    2000-01-01

    Today's nuclear technology has principally been based on the use of fissile U-235 and Pu-239. The existence of thorium in the nature and its potential use in the nuclear technology were not unfortunately into account with a sufficient importance. The global distributions of thorium and uranium reserves indicate that in general some developed countries such as the USA, Canada, Australia, France have considerable uranium reserves, and contrarily only some developing countries such as Turkey, Brazil, India, Egypt have considerable thorium reserves. The studies carried out on the thorium during the last 50 years have clearly showed that the thorium based nuclear fuels have the potential easily use in most of reactor types actually operated with the classical uranium based nuclear fuels without any considerable modification. In the case of the use of thorium based nuclear fuels in future nuclear energy production systems, the serious problems such as the excess of Pu-239, the proliferation potential of nuclear weapons, and also the anxious of nuclear terrorism will probably be resolved, and sustainable nuclear energy production will be realized in the next new century. (authors)

  3. Much cleaner nuclear energy from thorium

    International Nuclear Information System (INIS)

    Damveld, H.

    1998-01-01

    In Zaragoza, Spain, an experimental thorium reactor will be built, which can be an alternative for uranium reactors. A brief impression is given of activities in the Netherlands with respect to the so-called Energy Amplifier (EA), which is a combination of a nuclear power plant and an accelerator. EA is the idea of C. Rubbia of CERN in Geneva, Switzerland

  4. Lanthanides, thorium, iodine in terrestrail invertebrates

    International Nuclear Information System (INIS)

    Zhulidov, A.V.; Pokarzhevskij, A.D.; Katargin, N.V.; AN SSSR, Moscow

    1991-01-01

    It is shown that among examined terrestrial invertebrates the highest levels on lanthanide and thorium concentration are typical for animals, feeding on plant tissues - earthworms, molluscs, diploid. It is shown that there are no reasons to hope, that regularities of migration of transuranium elements and lanthanides in tropic chains are identical

  5. Towards proliferation-resistant thorium fuels

    International Nuclear Information System (INIS)

    Alhaj, M. Yousif; Mohamed, Nader M.A.; Badawi, Alya; Abou-Gabal, Hanaa H.

    2017-01-01

    Thorium-plutonium mixture is proposed as alternative nuclear reactor fuel to incinerate the increasing stockpile plutonium. However, this fuel will produce an amount of uranium with about 90% 233U at applicable discharge burnups (60GWD/MTU). This research focuses on proposing an optimum non proliferative thorium fuel, by adding a small amount of 238U to reduce the attractiveness of the resultant uranium. Three types of additive which contain 238U were used: 4.98% enriched, natural and depleted uranium. We found that introducing uranium to the fresh thorium-plutonium fuel reduces its performance even if the uranium was enriched up to 5%. While uranium admixtures reduce the quality of the reprocessed uranium, it also increases the quality of the plutonium. However, this increase is very low compared to the reduced quality of uranium. We also found that using uranium as admixture for thorium-plutonium mixed fuel increases the critical mass of the extracted uranium by a factor of two when using only 1% admixture of uranium. The higher the percentage of uranium admixture the higher the critical mass of the reprocessed one.

  6. Utilization of thorium in PWR type reactors

    International Nuclear Information System (INIS)

    Correa, F.

    1977-01-01

    Uranium 235 consumption is comparatively evaluated with thorium cycle for a PWR type reactor. Modifications are only made in fuels components. U-235 consumption is pratically unchanged in both cycles. Some good results are promised to the mixed U-238/Th-232 fuel cycle in 1/1 proportion [pt

  7. Practical introduction of thorium fuel cycles

    International Nuclear Information System (INIS)

    Kasten, P.R.

    1982-01-01

    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 233 U bred in the blanket of a fast breeder reactor is utilized as fissile fuel in thermal converter reactors)

  8. Candu reactors with thorium fuel cycles

    International Nuclear Information System (INIS)

    Hopwood, J.M.; Fehrenbach, P.; Duffey, R.; Kuran, S.; Ivanco, M.; Dyck, G.R.; Chan, P.S.W.; Tyagi, A.K.; Mancuso, C.

    2006-01-01

    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 550 0 C. 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

  9. Solvent-extraction purification of neptunium

    International Nuclear Information System (INIS)

    Kyser, E.A.; Hudlow, S.L.

    2008-01-01

    The Savannah River Site (SRS) has recovered 237 Np from reactor fuel that is currently being processed into NpO 2 for future production of 238 Pu. Several purification flowsheets have been utilized. An oxidizing solvent-extraction (SX) flowsheet was used to remove Fe, sulfate ion, and Th while simultaneously 237 Np, 238 Pu, u, and nonradioactive Ce(IV) was extracted into the tributyl phosphate (TBP) based organic solvent. A reducing SX flowsheet (second pass) removed the Ce and Pu and recovered both Np and U. The oxidizing flowsheet was necessary for solutions that contained excessive amounts of sulfate ion. Anion exchange was used to perform final purification of Np from Pu, U, and various non-actinide impurities. The Np(IV) in the purified solution was then oxalate-precipitated and calcined to an oxide for shipment to other facilities for storage and future target fabrication. Performance details of the SX purification and process difficulties are discussed. (authors)

  10. Thorium as an energy source. Opportunities for Norway; Thorium som energikilde - Muligheter for Norge

    Energy Technology Data Exchange (ETDEWEB)

    2008-02-15

    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

  11. Radon in air concentrations arising from storage of articles containing radium or thorium

    International Nuclear Information System (INIS)

    Slater, M.; Gooding, M.

    2006-01-01

    A major component of public and occupational radiation exposure worldwide arises from the inhalation of radon and thoron gases, produced during the decay of naturally occurring uranium and thorium respectively. Whilst radon and thoron exposures are normally associated with the natural environment, there may also be a risk associated with sources, manufactured articles and waste produced through refining and concentration of naturally occurring radioactive material. Sources and articles manufactured from refined uranium do not normally give rise to the release of radon as the uranium progeny are largely removed during production and, if removed, will take thousands of years to reach full equilibrium with the uranium parent isotopes. Exposure to radon -222 ( 222 Rn) may, however, arise in areas where the uranium-238 ( 238 U) daughter radium-226 ( 226 Ra) is concentrated, for example in the form of sources, luminous articles or low-specific activity (LSA) scale. Exposure to radon- 220 ( 220 Rn), otherwise known as thoron, may occur in areas where thorium isotopes are concentrated, for example as manufactured laboratory thorium compounds. This paper explores the issues affecting radon and thoron release from manufactured articles containing uranium and thorium and their progeny. A methodology is provided for the calculation of 222 Rn and 220 Rn in air concentrations likely to arise as a result of the storage and use of articles containing radium-226 ( 226 Ra) or thorium-232 ( 232 Th). The methodology provided in the document allows derivation of the equilibrium equivalent radon concentration and the radon exposure rate in circumstances where the ventilation rate and volume of the facility can be reliably estimated and the quantities of 226 Ra or 232 Th held are known. A critical variable in the calculation is the release fraction (i.e. the proportion of radon generated that is release to atmosphere), and this paper considers methods for estimating this parameter

  12. Prospective thorium fuels for future nuclear energy generation

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.

    2017-01-01

    In the beginning of the Nuclear Era, many countries were interested on thorium, particularly during the 1950 1970 periods. Nevertheless, since its discovery almost two centuries ago, the use of thorium has been restricted to gas mantles employed in gas lighting. 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. Nowadays approximately the worldwide yearly requirement of uranium for about 435 nuclear reactors in operation is 65,000 metric t. Therefore, alternative solutions for future must be developed. Thorium is nearly three times more abundant than uranium in The Earth's crust. Despite thorium is not a fissile material, 232 Th can be converted to 233 U (fissile) more efficiently than 238 U to 239 Pu. Besides this, thorium is an environment alternative energy source and also inherently resistant to proliferation.. Many countries had initiated research on thorium in the past, Nevertheless, the interest evanesced due new uranium resources discoveries and availability of enriched uranium at low prices from obsolete weapons. 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. A brief history of thorium and its utilization are presented, besides a very short discussion about prospective thorium nuclear fuels for the next generation of nuclear reactors. (author)

  13. Thorium and its future importance for nuclear energy generation

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.

    2015-01-01

    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, 232 Th can be converted to 233 U (fissile) more efficiently than 238 U to 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)

  14. 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.

  15. Occupational exposure to nickel, uranium and thorium in a nickel mine

    International Nuclear Information System (INIS)

    Azeredo, A.M.; Lipsztein, J.L.; Dias da Cunha, K.; Lourenco, M.C.; Lipsztein, J.L.; Miekeley, N.T.

    2002-01-01

    The workers involved in mining and milling ores are exposed in the workplace to many hazardous agents that can cause a health detriment. In this work, the measurements obtained in a nickel mineral processing facility in the Brazilian Central-West are presented. One of the most important hazardous agents in this facility is the aerosol present in the air that contains nickel, uranium and thorium. The aerosol is inhaled or ingested, metabolised and deposited in the whole body or in specific organs. The surveillance of internal contamination of workers was performed by analysis of urine, fecal and hair samples. The ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) method was used to analytically determine nickel, uranium and thorium in these biological samples. Additional data were obtained by the collection of air samples in the workplace. A cascade impactor with six stages was used to collect mineral dust particles with an aerodynamic diameter in the range of 0.64 to 19.4 μm. The particles impacted in each stage of the cascade impactor were analysed by PIXE (Particle Induced X ray Emission), which permits the determination of elemental mass air concentration and the MMAD (Mass Median Aerodynamic Diameter). The concentrations of nickel, uranium and thorium were determined in the aerosol samples. All the results were analysed using statistical methods and biokinetical modelling was applied to evaluate the internal contamination and to make a risk estimation. (author)

  16. High precision spectrophotometric analysis of thorium

    International Nuclear Information System (INIS)

    Palmieri, H.E.L.

    1984-01-01

    An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium when processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using dissodium ethylenediaminetetraacetate (EDTA) solution and alizarin-S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer programme. Besides the equivalence point, other parameters of titration were determined: the indicator concentration, the absorbance of the metal-indicator complex, and the stability constants of the metal-indicator and the metal-EDTA complexes. (Author) [pt

  17. Thorium spectrophotometric analysis with high precision

    International Nuclear Information System (INIS)

    Palmieri, H.E.L.

    1983-06-01

    An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using disodium ethylenediaminetetraacetate (EDTA) solution and alizarin S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer program. (author)

  18. 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

  19. Computer simulations for thorium doped tungsten crystals

    International Nuclear Information System (INIS)

    Eberhard, Bernd

    2009-01-01

    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 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 set of Langevin equations, i.e. stochastic

  20. Uranium and thorium deposits of Northern Ontario

    International Nuclear Information System (INIS)

    Robertson, J.A.; Gould, K.L.

    1983-01-01

    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

  1. Thorium oxide dissolution kinetics for hydroxide and carbonate complexation

    International Nuclear Information System (INIS)

    Jardin, R.; Curran, V.; Czerwinski, K.R.

    2002-01-01

    The purpose of this project was to determine the kinetics and thermodynamics of thorium oxide dissolution in the environment. Solubility is important because it establishes an upper concentration limit on the concentration of a dissolved radionuclide in solution L1. While understanding the behavior of thorium fuels in the proposed repository at Yucca Mountain is most applicable, a more rigorous study of thorium solubility over a wide pH range was performed so that the data could also be used to model the behavior of thorium fuels in any environmental system. To achieve this, the kinetics and thermodynamics of thorium oxide dissolution under both pure argon and argon with P CO2 of 0. 1 were studied under the full pH range available in each atmosphere. In addition, thorium oxide powder remnants were studied after each experiment to examine structural changes that may affect kinetics

  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 Multimedia

    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. Chemical analysis used in nuclear fuels reprocessing of uranium and thorium

    International Nuclear Information System (INIS)

    Schvartzman, M.M.A.M.

    1986-01-01

    An overall review of the analytical chemistry in nuclear fuel reprocessing is done. In Purex and Thorex process flowsheets, the analyses required to the control of the process, balance and accountability of fissile and fertile materials, and final product specification are pointed out. Some analytical methods applied to the determination of uranium, plutonium, thorium, nitric acid, tributylphosphate and fission products are described. Specific features of the analytical laboratories are presented. The radioactivity level of the samples requires facilities as shielded cells and glove boxes, and handling by remote control. Finally it is reported an application of one analytical method to evaluate thorium content in organic and aqueous solutions, in cold tests of Thorex process. These tests were performed at CDTN/NUCLEBRAS. (author) [pt

  5. Thorium as a substitute for uranium

    International Nuclear Information System (INIS)

    Hunt, H.

    1977-01-01

    Reference is made to the paper by E. Teller in Atom, February 1977, who suggested that it appears, at least theoretically, that the use of a thorium cycle in thermal reactors would give enough nuclear fuel for a long time to come, and so avoid the need for using Pu in fast reactors. This appears at first sight to be an attractive proposition, but loses some of this attraction on close examination. Reasons for this are discussed. (U.K.)

  6. Thorium dioxide: properties and nuclear applications

    International Nuclear Information System (INIS)

    Belle, J.; Berman, R.M.

    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

  7. Long term radiological impact of thorium extraction

    International Nuclear Information System (INIS)

    Menard, S.; Schapira, J.P.

    1995-01-01

    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 232 Th 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 228 Ra, 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 220 Rn. 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

  8. Thorium impact on tobacco root transcriptome

    Czech Academy of Sciences Publication Activity Database

    Mazari, Kateřina; Landa, Přemysl; Přerostová, Sylva; Müller, Karel; Vaňková, Radomíra; Soudek, Petr; Vaněk, Tomáš

    2017-01-01

    Roč. 325, MAR 5 (2017), s. 163-169 ISSN 0304-3894 R&D Projects: GA MŠk(CZ) LD11073; GA MŠk(CZ) LD13029 Institutional support: RVO:61389030 Keywords : arabidopsis-thaliana roots * juncea var. foliosa * cadmium accumulation * deficiency responses * mineral- nutrition * gene-expression * plant transfer * iron uptake * uranium * soil * Microarray * Thorium * Gene expression * Toxicity * Nicotiana tabacum Subject RIV: ED - Physiology OBOR OECD: Plant sciences, botany Impact factor: 6.065, year: 2016

  9. 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.

  10. Structure of tetrakis(salicylaldehydato)thorium(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R J; Rickard, C E.F. [Auckland Univ. (New Zealand). Dept. of Chemistry

    1977-01-01

    The structure of tetrakis(salicylaldehydato)thorium(IV) has been determined by single crystal X-ray crystallography. The crystals are tetragonal, a = 10.214, b = 23.744 A, space group P4/sub 1/. The molecules are eight coordinate, the coordination polyhedron being a dodecahedron with approximate Dsub(2d) symmetry. The dodecahedral A sites are occupied by the aldehydic oxygens and the phenolic oxygens occupy the B sites.

  11. Uranium and Thorium in zircon sands processed in Northeastern Brazil

    International Nuclear Information System (INIS)

    Hazin, Clovis A.; Farias, Emerson E. G. de

    2008-01-01

    Zircon the main mineral of zirconium is a silicate mineral product (ZrSiO 4 ) obtained from beach sand deposits, along with other minerals such as kyanite, ilmenite, and rutile. All zircons contain some radioactive impurities due to the presence of uranium, thorium and their respective decay products in the crystalline structure of zircon, as well as potassium-40. Uranium and thorium substitute Zr 4+ in the mineral through an internal process called isomorphous replacement of zirconium. For this study, samples were collected both from a mineral sand processing plant located in the coastal region of Northeastern brazil and from the beach sands used in the process. The aim of this study was to assess the 238 U, 232 Th and 40 K contents in the beach sands and in the mineral products extracted from the sands in that facility, with special emphasis on zircon. Measurements were performed through gamma spectrometry, by using a high-purity germanium detector (HPGe) coupled to a multichannel analyzer. Activity concentration for 238 U and 232 Th in zircon sands ranged from 5462±143 to 19286±46 Bq kg -1 and from 1016±7 to 7162±38 Bq kg -1 , respectively. For 40 K, on the other hand, activity concentration values ranged from 81±14 to 681±26 Bq Kg -1 . The results of the measurements carried out for raw sand samples showed activity concentrations between 2.7±0.6 and 7.9±0.9 Bq kg -1 and 6.5±0.4 and 9.4±0.6 Bq kg -1 for 238 U and 23T h respectively, and from 48.8±3.1 to 76.1±2.4 Bq kg -1 for 40 K. Activity concentrations of 238 U and 232 Th in kyanite, ilmenite and rutile samples were also determined. (author)

  12. Large-scale nuclear energy from the thorium cycle

    International Nuclear Information System (INIS)

    Lewis, W.B.; Duret, M.F.; Craig, D.S.; Veeder, J.I.; Bain, A.S.

    1973-02-01

    The thorium fuel cycle in CANDU (Canada Deuterium Uranium) reactors challenges breeders and fusion as the simplest means of meeting the world's large-scale demands for energy for centuries. Thorium oxide fuel allows high power density with excellent neutron economy. The combination of thorium fuel with organic caloporteur promises easy maintenance and high availability of the whole plant. The total fuelling cost including charges on the inventory is estimated to be attractively low. (author) [fr

  13. 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.

  14. 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.

  15. Self-Sustaining Thorium Boiling Water Reactors

    International Nuclear Information System (INIS)

    Greenspan, Ehud; Gorman, Phillip M.; Bogetic, Sandra; Seifried, Jeffrey E.; Zhang, Guanheng; Varela, Christopher R.; Fratoni, Massimiliano; Vijic, Jasmina J.; Downar, Thomas; Hall, Andrew; Ward, Andrew; Jarrett, Michael; Wysocki, Aaron; Xu, Yunlin; Kazimi, Mujid; Shirvan, Koroush; Mieloszyk, Alexander; Todosow, Michael; Brown, Nicolas; Cheng, Lap

    2015-01-01

    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. 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.

  17. 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...

  18. Thorium in the workplace measurement intercomparison

    International Nuclear Information System (INIS)

    Modna, D.K.; Jerome, S.M.; White, M.A.; Woods, M.J.

    2000-01-01

    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 232 Th and its daughter nuclides. Thus, to monitor the workforce effectively, it is important to be able to measure both 232 Th and the decay products of 232 Th 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 232 Th, 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

  19. Laboratory of minerals purification

    International Nuclear Information System (INIS)

    2002-01-01

    The laboratory of minerals purification was organized in 1962 where with application of modern physical and chemical methods were investigated the mechanism of flotation reagents interaction with minerals' surface, was elaborated technologies on rising complexity of using of republic's minerals

  20. Health status and body radioactivity of former thorium workers

    International Nuclear Information System (INIS)

    Stehney, A.F.; Polednak, A.P.; Rundo, J.; Brues, A.M.; Lucas, H.F. Jr.; Patten, B.C.; Rowland, R.E.

    1981-01-01

    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. Use of a moving-bed ion-exchange column for plutonium purification; Utilisation d'une colonne echangeuse d'ions a lit mobile pour la purification du plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Sabatier, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    When large amounts of fissile matter have to be purified on ion exchange resins, it is difficult to use a fixed bed because of its limiting maximum size. With a moving bed it is possible to ensure a continuous production which can easily be integrated into a purification line on account of its large production capacity. The installation described in this report is derived from an American prototype designed for uranium separation. As a result of many modifications, it is suitable for the purification of plutonium several such columns will shortly be operating in various French centres. The moving bed column, which has a diameter of 25 mm, was first tried with the uranium-thorium mixture; then, after modifications on the plutonium-uranium mixture. The production capacity will depend on the plutonium concentration which can be tolerated in the effluents. It is possible to treat 150 gm/day of plutonium alone; the effluents obtained have a concentration of around of 1 mg/l. The plutonium-uranium separation is improved by a 5 N acidic rinsing as well as by a temperature increase. The decontamination factor increased from 14 in 7 N nitric acid solution to 115 in 5 N nitric acid solution. A temperature increase of about 20 C leads to a decontamination factor of over 500. This result is sufficient encouraging for the possibility of future installations operating in optimum temperature conditions, i.e. 60-65 C, to be considered. (author) [French] Des que l'on desire purifier sur resine echangeuse d'ions des quantites importantes de matieres fissiles, le lit fixe devient difficilement exploitable par suite des dimensions maximum possibles. Le lit mobile permet une production continue pouvant s'integrer facilement par sa capacite de traitement dans une chaine de purification. L'installation decrite dans ce rapport est derivee d'un prototype americain destine a la separation de l'uranium. De nombreuses modifications en font un ensemble utilisable pour la purification du

  2. Power Reactor Thoria Reprocessing Facility (PRTRF), Trombay

    International Nuclear Information System (INIS)

    Dhami, P.S; Yadav, J.S; Agarwal, K.

    2017-01-01

    Exploitation of the abundant thorium resources to meet sustained energy demand forms the basis of the Indian nuclear energy programme. To gain reprocessing experience in thorium fuel cycle, thoria was irradiated in research reactor CIRUS in early sixties. Later in eighties, thoria bundles were used for initial flux flattening in some of the pressurized heavy water reactors (PHWRs). The research reactor irradiated thoria contained small content (∼ 2-3ppm) of "2"3"2U in "2"3"3U product, which did not pose any significant radiological problems during processing in Uranium Thorium Separation Facility (UTSF), Trombay. Thoria irradiated in PHWRs on discharge contained (∼ 0.5-1.5% "2"3"3U with significant "2"3"2U content (100-500 ppm) requiring special radiological attention. Based on the experience from UTSF, a new facility viz. Power Reactor Thoria Reprocessing Facility (PRTRF), Trombay was built which was hot commissioned in the year 2015

  3. The hydrolysis of thorium dicarbide and of mixed uranium-thorium dicarbides

    International Nuclear Information System (INIS)

    Del Litto, B.

    1966-09-01

    The hydrolysis of thorium dicarbide leads to the formation of a complex mixture of gaseous and condensed carbon hydrides. The temperature, between 25 and 100 deg. C, has no influence on the nature and composition of the gas phase. The reaction kinetics, however, are strongly temperature dependent. In a hydrochloric medium, an enrichment in hydrogen of the gas mixture is observed. On the other hand a decrease in hydrogen and an increase in acetylene content take place in an oxidizing medium. The general results can be satisfactorily interpreted through a reaction mechanism involving C-C radical groups. In the same way, the hydrolysis of uranium-thorium-carbon ternary alloys leads to the formation of gaseous and condensed carbon hydrides. The variation of the composition of the gas phase versus uranium content in the alloy suggests an hypothesis about the carbon-carbon distance in the alloy crystal lattice. The variation of methane content, on the other hand, has lead us to discuss the nature of the various phases present in uranium-carbon alloys and carbon-rich uranium-thorium-carbon alloys. We have reached the conclusion that these alloys include a proportion of monocarbide which is dependent upon the ratio. Th/(Th + U). We put forward a diagram of the system uranium-carbon with features proper to explain some phenomena which have been observed in the uranium-thorium-carbon ternary diagram. (author) [fr

  4. Present state and perspective of research on thorium cycle

    International Nuclear Information System (INIS)

    Kimura, Itsuro

    1994-01-01

    For the prosperity of Japan and the welfare of mankind in the world, enormous quantity of energy is required in 21st century, and the general circumstances of energy and nuclear power are described. In addition to the present nuclear power using mostly 235 U and the plutonium produced from 238 U, it is the thorium cycle that 233 U produced from the third nuclear fuel, thorium, is used for electric power generation as an energy source. In this report, the 'General research on thorium cycle as a promising energy source in and after 21st century' is outlined, which has been advanced by accepting the subsidy of scientific research expense of the Ministry of Education. The features of the thorium cycle and the nuclear data and the nuclear characteristics in comparison with uranium-plutonium reactors are described. The trend of the research and development in the world and in Japan is reported. Two general researches were carried out for five years from fiscal year 1988 to 1992 on the thorium cycle. The results of the research on the nuclear data, the design of thorium reactors, the criticality experiment and analysis, thorium hybrid, thorium fuel, molten salt, fuel reprocessing and radiation safety are reported. (K.I.)

  5. Evaluation of thorium based nuclear fuel. Chemical aspects

    International Nuclear Information System (INIS)

    Konings, R.J.M.; Blankenvoorde, P.J.A.M.; Cordfunke, E.H.P.; Bakker, K.

    1995-07-01

    This report describes the chemical aspects of a thorium-based fuel cycle. It is part of a series devoted to the study of thorium-based fuel as a means to achieve a considerable reduction of the radiotoxicity of the waste from nuclear power production. Therefore special emphasis is placed on fuel (re-)fabrication and fuel reprocessing in the present work. (orig.)

  6. Economics and utilization of thorium in nuclear reactors

    International Nuclear Information System (INIS)

    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

  7. Evaluation of thorium based nuclear fuel. Chemical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Konings, R.J.M.; Blankenvoorde, P.J.A.M.; Cordfunke, E.H.P.; Bakker, K.

    1995-07-01

    This report describes the chemical aspects of a thorium-based fuel cycle. It is part of a series devoted to the study of thorium-based fuel as a means to achieve a considerable reduction of the radiotoxicity of the waste from nuclear power production. Therefore special emphasis is placed on fuel (re-)fabrication and fuel reprocessing in the present work. (orig.).

  8. Automated methods for thorium determination in liquids, solids and aerosols

    International Nuclear Information System (INIS)

    Robertson, R.; Stuart, J.E.

    1984-01-01

    Methodology for determining trace thorium levels in a variety of sample types for compliance purposes was developed. Thorium in filtered water samples is concentrated by ferric hydroxide co-precipitation. Aerosols on glass-fibre, cellulose ester or teflon filters are acid digested and thorium is concentrated by lanthanum fluoride co-precipitation. Chemical separation and measurement are then done on a Technicon AAII-C auto-analyzer via TTA-solvent extraction and colorimetry using the thorium-arsenazo III colour complex. Solid samples are acid digested and thorium is concentrated and separated using lanthanum fluoride co-precipitation followed by anion-exchange chromatography. Measurement is then carried out on the autoanalyzer by direct development of the thorium-arsenazo III colour complex. Chemical yields are determined through the addition of thorium-234 tracer with assay by gamma-ray spectrometry. The sensitivities of the methods for liquids, aerosols and solids are approximately 1μg/L,0.5μg and 0.5 μg/g respectively. At thorium levels about ten times the detection limits, accuracy and reproducibility are typically +-10 percent for liquids and aerosols and +- 15 percent for solid samples

  9. Competitive biosorption of thorium and uranium by actinomycetes

    International Nuclear Information System (INIS)

    Nakajima, Akira; Tsuruta, Takehiko

    2002-01-01

    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) 2 2+ and UO 2 2+ , respectively. (author)

  10. A study on the structure of thorium salt solutions

    International Nuclear Information System (INIS)

    Magini, M.; Cabrini, A.; Di Bartolomeo, A.

    1975-01-01

    The structure of highly hydrolyzed thorium salt solutions has been investigated by large and small angle X-ray scattering techniques. The diffraction data obtained with large angle measurements show the presence in solution of microcrystalline particles with the thorium oxide structure. Particles larger than those were discovered by small angle measurements. A possible shape of these colloidal particles has been discussed

  11. REGENERATION OF FISSION-PRODUCT-CONTAINING MAGNESIUM-THORIUM ALLOYS

    Science.gov (United States)

    Chiotti, P.

    1964-02-01

    A process of regenerating a magnesium-thorium alloy contaminated with fission products, protactinium, and uranium is presented. A molten mixture of KCl--LiCl-MgCl/sub 2/ is added to the molten alloy whereby the alkali, alkaline parth, and rare earth fission products (including yttrium) and some of the thorium and uranium are chlorinated and

  12. Light water reactors with a denatured thorium fuel cycle

    International Nuclear Information System (INIS)

    1978-05-01

    Discussed in this paper is the performance of denatured thorium fuel cycles in PWR plants of conventional design, such as those currently in operation or under construction. Although some improvement in U 3 O 8 utilization is anticipated in PWRs optimized explicitly for the denatured thorium fuel cycle, this paper is limited to a discussion of the performance of denatured thorium fuels in conventional PWRs and consequently the data presented is representative of the use of thorium fuel in existing PWRs or those presently under construction. In subsequent sections of this paper, the design of the PWR, its performance on the denatured thorium fuel cycle, safety, accident and environmental considerations, and technological status and R and D requirements are discussed

  13. Environmental and radiological aspects of thorium processing in India

    International Nuclear Information System (INIS)

    Rudran, Kamala; Paul, A.C.; Pillai, P.M.B.; Saha, S.C.; Vidyasagar, D.; Sawant, Pramilla D.

    1997-01-01

    India has an active programme for using thorium as third stage self- sustaining nuclear fuel. A significant amount of thorium is also used in the gas mantle industry. The presently estimated monazite deposits amounting to five million tonnes are distributed in the beach sands of south western and eastern coasts and some areas in Andhra Pradesh. The sands are processed for recovery of rare earth minerals and thorium. The mineral processing and thorium separation involves hazards to workers from exposure to radiation, radioactive and silica bearing dusts as well as from conventional chemicals used in the processing. Releases of wastes from the plants may necessitate environmental surveillance. The present paper reviews the hazards envisaged, steps taken to mitigate such hazards and achievements in this regard in the thorium industry in India. (author)

  14. Determination of microquantities of zirconium and thorium in uranium dioxide

    International Nuclear Information System (INIS)

    Weber de D'Alessio, Ana; Zucal, Raquel.

    1975-07-01

    A method for the determination of 10 to 50 ppm of zirconium and thorium in uranium IV oxide of nuclear purity is established. Zirconium and thorium are retained in a strong cation-exchange resin Dowex 50 WX8 in 1 M HCl. Zirconium is eluted with 0,5% oxalic acid solution and thorium with 4% ammonium oxalate. The colorimetric determination of zirconium with xilenol orange is done in perchloric acid after destructtion of oxalic acid and thorium is determined with arsenazo III in 5 M HCl. 10 μg of each element were determined with a standard deviation of 2,1% for thorium and 3,4% for zirconium. (author) [es

  15. Simulation an Accelerator driven Subcritical Reactor core with thorium fuel

    International Nuclear Information System (INIS)

    Shirmohammadi, L.; Pazirandeh, A.

    2011-01-01

    The main purpose of this work is simulation An Accelerator driven Subcritical core with Thorium as a new generation nuclear fuel. In this design core , A subcritical core coupled to an accelerator with proton beam (E p =1 GeV) is simulated by MCNPX code .Although the main purpose of ADS systems are transmutation and use MA (Minor Actinides) as a nuclear fuel but another use of these systems are use thorium fuel. This simulated core has two fuel assembly type : (Th-U) and (U-Pu) . Consequence , Neutronic parameters related to ADS core are calculated. It has shown that Thorium fuel is use able in this core and less nuclear waste ,Although Iran has not Thorium reserves but study on Thorium fuel cycle can open a new horizontal in use nuclear energy as a clean energy and without nuclear waste

  16. Study Of Thorium As A Nuclear Fuel.

    Directory of Open Access Journals (Sweden)

    Prakash Humane

    2017-10-01

    Full Text Available Conventional fuel sources for power generation are to be replacing by nuclear power sources like nuclear fuel Uranium. But Uranium-235 is the only fissile fuel which is in 0.72 found in nature as an isotope of Uranium-238. U-238 is abundant in nature which is not fissile while U-239 by alpha decay naturally converted to Uranium- 235. For accompanying this nuclear fuel there is another nuclear fuel Thorium is present in nature is abundant can be used as nuclear fuel and is as much as safe and portable like U-235.

  17. Electronic States in Thorium under Pressure

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Jan, J. P.

    1980-01-01

    We have used the local-density formalism and the atomic-sphere approximation to calculate self-consistently the electronic properties of thorium at pressures up to 400 kbar. The derived equation of state agrees very well with static pressure experiments and shock data. Below the Fermi level (EF......) the electronic band structure is formed by 7s and 6d states while the bottom of a relatively broad 5f band is positioned 0.07 Ry above EF. The calculated extremal areas of the Fermi surface and their calculated pressure dependence agree with earlier calculations and with de Haas-van Alphen measurements...

  18. Prospective thorium fuels for future 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)

    2017-07-01

    In the beginning of the Nuclear Era, many countries were interested on thorium, particularly during the 1950 1970 periods. Nevertheless, since its discovery almost two centuries ago, the use of thorium has been restricted to gas mantles employed in gas lighting. 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. Nowadays approximately the worldwide yearly requirement of uranium for about 435 nuclear reactors in operation is 65,000 metric t. Therefore, alternative solutions for future must be developed. 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, thorium is an environment alternative energy source and also inherently resistant to proliferation.. Many countries had initiated research on thorium in the past, Nevertheless, the interest evanesced due new uranium resources discoveries and availability of enriched uranium at low prices from obsolete weapons. 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. A brief history of thorium and its utilization are presented, besides a very short discussion about prospective thorium nuclear fuels for the next generation of nuclear reactors. (author)

  19. Water purification in Borexino

    Energy Technology Data Exchange (ETDEWEB)

    Giammarchi, M. [Infn Milano (Italy); Balata, M.; Ioannucci, L.; Nisi, S. [Laboratori Nazionali del Gran Sasso (Italy); Goretti, A.; Ianni, A. [Princeton University (United States); Miramonti, L. [Dip. di Fisica dell' Università di Milano e Infn (Italy)

    2013-08-08

    Astroparticle Physics and Underground experiments searching for rare nuclear events, need high purity materials to act as detectors or detector shielding. Water has the advantage of being cheap, dense and easily available. Most of all, water can be purified to the goal of obatining a high level of radiopurity. Water Purification can be achieved by means of a combination of processes, including filtration, reverse osmosis, deionization and gas stripping. The Water Purification System for the Borexino experiment, will be described together with its main performances.

  20. Thorium molten-salt nuclear energy synergetics

    International Nuclear Information System (INIS)

    Furukawa, Kazuo

    1989-01-01

    One of the most practical and rational approaches for establishing the idealistic Thorium resource utilization program has been presented, which might be effective to solve the principal energy problems, concerning safety, proliferation and terrorism, resource, power size and fuel cycle economy, for the next century. The first step will be the development of Small Molten-Salt Reactors as a flexible power station, which is suitable for early commercialization of Th reactors not necessarily competing with proven Large Solid-Fuel Reactors. Therefore, the more detailed design works and practical R and D planning should be performed under the international cooperations soon, soundly depending on the basic technology established by ORNL already. R and D cost would be surprisingly low. This reactor(MSR) seems to be idealistic not only in power-size, siting, safety, safeguard and economy, but also as an effective partner of Molten-Salt Fissile Breeders(MSB) in order to establish the simplest and economical Thorium molten-salt breeding fuel cycle named THORIMS-NES in all over the world including the developing countries and isolated areas. This would be one of the most practical replies to the Lilienthal's appeal of 'A NEW START' in Nuclear Energy. (author)

  1. The resonance integral of thorium metal rods

    Energy Technology Data Exchange (ETDEWEB)

    Hellstrand, E; Weitman, J

    1960-03-15

    The resonance integral for thorium metal rods of different diameters has been determined by the activation method. The irradiations took place in the central channel of the reactor R1, where the energy dependence of the neutron flux had earlier been investigated with a fast chopper up to about 1 keV. The absolute calibration was made with gold as a standard. The true resonance integral for gold was taken from the literature as 1,500 {+-} 35 b. The experimental values for thorium were fitted to two alternative expressions with the following results: RI = (1.70 + 15.9{radical}(S/M)) {+-} 5.5%; RI 17.3{radical}(S/M + 0.06) {+-} 5.5 %. The measurements were made for S/M values in the range 0.14 - 0.87 cm{sup 2}/g. The main contribution to the margin of errors arises from the uncertainties in the cross sections used and in the correction for the departure of the neutron energy distribution from the 1/E form.

  2. Phthalocyaninato complexes of thorium, protactinium and uranium

    International Nuclear Information System (INIS)

    Beck, O.F.

    1985-01-01

    For the preparation of Bis(phthalocyaninato)-actinoid(IV) complexes, AnPc 2 , a new optimizing synthesis procedure was developed, with which it was possible to prepare spectrally pure, that is, H 2 Pc-free, ThPc 2 , UPc 2 and the isostructurally similar 231 PaPc 2 .PaPc 2 . This was verified with the help of electron spectra, which were compared to preparations which were synthesized in another manner. The corresponding perfluorinated compounds were also produced for thorium and uranium by use of tetrafluorophthalic acid nitrile instead of phthalic acid nitrile as initial product. Electron and infrared spectra show the typical bands of the non-substituted complexes. By the attempt to produce a mono(phthalocyaninato)-thorium complex with the use of ThI 4 as initial material a pyridine-extracted pure ThPcI 2 (py) 2 was obtained with a typical mono(phthalocyaninato) complex electron spectrum, an extremely moisture sensitive compound which in water or acids decomposes and produces H 2 Pc. (orig./RB) [de

  3. Use of nuclear recoil for separating 228Ra, 224Ra, and 233Pa from colloidal thorium

    International Nuclear Information System (INIS)

    Beydon, J.; Gratot, I.

    1968-01-01

    By using α-recoil it is possible to separate by dialysis the α disintegration products (224 Ra; 228 Ra) of thorium from colloidal thorium hydroxide.The use of n, γ recoil allows the separation of 233 Pa produced by the neutron irradiation of thorium, on condition that the colloidal thorium hydroxide is irradiated in the presence of a dispersing. (author) [fr

  4. The low enriched fuel cycle in the GA 1160 MW design and the switch-over to thorium

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, H.

    1974-03-15

    Calculations for the GA 1160 MW HTR are presented. The aim of these investigations was to compare the Low Enriched Uranium (LEU) cycle and the Thorium cycle for the GA 1160 MW HTR both using the same GA designed integral block fuel element. The total fuel cycle cost for the equilibrium cycle comes out to be about 16% cheaper for the Thorium cycle than for the Low-Enriched cycle. However, these favorable results for the thorium cycle are completely dependent on the availability of reprocessing and refabrication facilities, for costs comparable with the costs used for these investigations. The possibility of starting the reactor on a LEU 3 year cycle and later switching over to a thorium 4 year cycle was investigated. No cost penalties were found to be paid during the switch-over. The problems of local power peaks and age factors were not investigated in greater detail as only integral physical quantities were obtained from the neutron physics calculations. However, no indications of any problem in the switch-over phase were given. Elaborate 3-dimensional methods are necessary for further investigation of these types of problems.

  5. A new method for determination of trace amount thorium-spectrophotometric determination of thorium in aqueous phase by chlorophosphonazo-mA

    International Nuclear Information System (INIS)

    Xia Yuanxian; Qian Hesheng

    1986-01-01

    In this paper the spectrophotometric method for determination of trace amount of thorium in weak acidic medium by chlorophosphonazo-mA is described. The composition of the complex was estimated to be 1:4 by slope ratio method. The apparent molar absorption of thorium at 675 nm is 9.2 x 10 4 . Beer's law is obeyed for 0-12.0 μg of thorium in 10 ml solution. The coefficient of variation for thorium is 0.88%. The method has been applied to the determination of trace amounts of thorium in the extraction process of thorium

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

    International Nuclear Information System (INIS)

    Joo, H. K.; Noh, J. M.; Yoo, J. W.

    2002-01-01

    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

  7. Sodium purification in Rapsodie

    International Nuclear Information System (INIS)

    Giraud, B.

    1968-01-01

    This report is one of a series of publications presenting the main results of tests carried out during the start-up of the first french fast neutron reactor: Rapsodie. The article presents the sodium purification techniques used in the reactor cooling circuits both from the constructional point of view and with respect to results obtained during the first years working. (author) [fr

  8. Determination of Uranium and Thorium in Drinking and Seawater

    International Nuclear Information System (INIS)

    Rozmaric Macefat, M.; Gojmerac Ivsic, A.; Grahek, Z.; Barisic, D.

    2008-01-01

    Uranium and thorium are the first members of natural radioactive chain which makes their determination in natural materials interesting from geochemical and radioecological aspect. They are quantitatively determined as elements by spectrophotometric method and/or their radioisotopes by alpha spectrometry and ICP-MS. It is necessary to develop inexpensive, rapid and sensitive methods for the routine researches because of continuous monitoring of the radioactivity level. Development of a new method for the isolation of uranium and thorium from liquid samples and subsequent spectrophotometric determination is described in this paper. It is possible to isolate uranium and thorium from drinking and seawater using extraction chromatography or ion exchange chromatography. Uranium and thorium can be strongly bound on the TRU extraction chromatographic resin from 3 mol dm -3 HNO 3 (chemical recovery is 100 percent) and separated from other interfering elements (sodium, potassium, calcium, strontium etc). Their mutual separation is possible by using anion exchanger Amberlite CG-400 (NO 3 - form). From alcoholic solutions of nitric acid thorium can be strongly bound on the anion exchanger while uranium is much more weakly bound which enables its separation from thorium. After the separation, uranium and thorium are determined by spectrophotometric method with arsenazo III at 652 nm and 662 nm respectively. Developed method enables selection of the optimal mode of isolation for the given purposes.(author)

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

    International Nuclear Information System (INIS)

    1987-03-01

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    Aslani, M.A.A.; Akyil, S.; Eral, M.

    1997-01-01

    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

  12. Mechanical structure and problem of thorium molten salt reactor

    International Nuclear Information System (INIS)

    Kamei, Takashi

    2011-01-01

    After Fukushima Daiichi accident, there became great interest in Thorium Molten Salt Reactor (MSR) for the safety as station blackout leading to auto drainage of molten salts with freeze valve. This article described mechanical structure of MSR and problems of materials and pipes. Material corrosion problem by molten salts would be solved using modified Hastelloy N with Ti and Nb added, which should be confirmed by operation of an experimental reactor. Trends in international activities of MSR were also referred including China declaring MSR development in January 2011 to solve thorium contamination issues at rare earth production and India rich in thorium resources. (T. Tanaka)

  13. Spectrophotometric Determination of Thorium in Low Grade Minerals and Ores

    Energy Technology Data Exchange (ETDEWEB)

    Arnfelt, A L; Edmundsson, I

    1960-08-15

    The following method is intended for the determination of microgram quantities of thorium in samples of minerals and ores. The mineral sample is decomposed by repeated sintering with sodium peroxide. After digestion with water thorium peroxide hydrate is recovered by centrifugation and dissolved in hydrochloric acid. Thorium is determined spectrophotometrically with naphtarson after its separation from metals forming chloro complexes which are adsorbed on a strongly basic anion exchange resin. Interferences from a few different ions have been studied. The time required for the analysis of one sample is about 4 hours, when analysing 12 samples simultaneously

  14. Spectrophotometric Determination of Thorium in Low Grade Minerals and Ores

    International Nuclear Information System (INIS)

    Arnfelt, A.L.; Edmundsson, I.

    1960-08-01

    The following method is intended for the determination of microgram quantities of thorium in samples of minerals and ores. The mineral sample is decomposed by repeated sintering with sodium peroxide. After digestion with water thorium peroxide hydrate is recovered by centrifugation and dissolved in hydrochloric acid. Thorium is determined spectrophotometrically with naphtarson after its separation from metals forming chloro complexes which are adsorbed on a strongly basic anion exchange resin. Interferences from a few different ions have been studied. The time required for the analysis of one sample is about 4 hours, when analysing 12 samples simultaneously

  15. On the radiology of thorium-uranium electro breeding

    International Nuclear Information System (INIS)

    Gai, E.V.; Rabotnov, N.S.; Shubin, Y.N.

    1995-01-01

    Radiological problems arising in thorium-uranium electro-breeding with thorium accelerator target are discussed. Following radiological problems are discussed and evaluated in simplified model calculations: U-232 formation, accumulation of light Th isotopes in (n, xn) reactions on thorium target: accumulation of the same nuclides in final repository after alpha-decay of uranium isotopes. The qualitative comparison of U-Pu and U-Th fuel cycles is performed. The problems seem to be serious enough to justify detailed quantitative investigation. (authors)

  16. Heavy water reactors on the denatured thorium cycles

    International Nuclear Information System (INIS)

    1978-05-01

    This paper presents preliminary technical and economic data to INFCE on the denatured U-233/Thorium fuel cycle for use in early comparisons of alternate nuclear systems. The once-through uranium fuel cycle is discussed in a companion paper. In presenting this preliminary information at this time, it is recognized that there are several other denatured thorium fuel cycles of potential interest, such as the U-235/thorium cycle which could be implemented at an earlier date. Information on these alternate cycles is currently being developed, and will be provided to INFCE when available

  17. Thorium fuel performance assessment in HTRs

    Energy Technology Data Exchange (ETDEWEB)

    Allelein, H.-J. [Forschungszentrum Jülich, D-52425 Jülich (Germany); RWTH Aachen, D-52072 Aachen (Germany); Kania, M.J.; Nabielek, H. [Forschungszentrum Jülich, D-52425 Jülich (Germany); Verfondern, K., E-mail: k.verfondern@fz-juelich.de [Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2014-05-01

    Thorium as a nuclear fuel is receiving 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 HTR development employed thorium together with high-enriched uranium. After 1980, most HTR fuel systems switched to low-enriched uranium. After completing fuel development for AVR and THTR with BISO coated particles, the German program expanded efforts on a new program utilizing thorium and high-enriched uranium TRISO coated particles for advanced HTR concepts for process heat applications (PNP) and direct-cycle electricity production (HHT). The combination of 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 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 HTR 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 up to 13% FIMA and fast fluences to 8 × 10{sup 25} m{sup −2} (E > 16 fJ), the results exceed the design limits on manufacturing and operational requirements for the German HTR Modul concept, which were: <6.5 × 10{sup −5} for manufacturing; <2 × 10{sup −4} for normal operating conditions; and <5 × 10{sup −4} for accident conditions. These

  18. Thorium-particulate matter interaction. Thorium complexing capacity of oceanic particulate matter: Theory

    International Nuclear Information System (INIS)

    Hirose, Katsumi; Tanque, Eiichiro

    1994-01-01

    The interaction between thorium and oceanic particulate matter was examined experimentally by using chemical equilibrium techniques. Thorium reacts quantitatively with the organic binding site of Particulate Matter (PM) in 0.1 mol/L HCl solution by complexation, which is equilibrated within 34 h. According to mass balance analysis, thorium forms a 1:1 complex with the organic binding site in PM, whose conditional stability constant is 10 6.6 L/mol. The Th adsorption ability is present even in 6.9 mol/L HCl solution although the amount of Th adsorption decreases with increasing acidity in the solution. Interferences to Th adsorption by Fe(III) suggests that other metals cannot react with PM in more than 0.1 mol/L HCl solutions when concentrations of other metals are the same level of Th. The competitive reaction between Th and Fe(III) occurs in higher Fe concentrations, which means that the organic binding site is nonspecific for Th. A vertical profile of Th complexing capacity of PM in the western North Pacific is characterized; that is, the Th complexing capacity shows a surface maximum and decreases rapidly with depth

  19. Thorium valency in molten alkali halides in equilibrium with metallic thorium

    International Nuclear Information System (INIS)

    Smirnov, M.V.; Kudyakov, V.Ya.

    1983-01-01

    Metallic thorium is shown to corrode in molten alkali halides even in the absence of external oxidizing agents, alkali cations acting as oxidizing agents. Its corrosion rate grows in the series of alkali chlorides from LiCl to CsCl at constant temperature. Substituting halide anions for one another exerts a smaller influence, the rate rising slightly in going from chlorides to bromides and iodides, having the same alkali cations. Thorium valency is determined coulometrically, the metal being dissolved anodically in molten alkali halides and their mixtures. In fluoride melts it is equal to 4 but in chloride, bromide and iodide ones, as a rule, it has non-integral values between 4 and 2 which diminish as the temperature is raised, as the thorium concentration is lowered, as the radii of alkali cations decrease and those of halide anions increase. The emf of cells Th/N ThHlsub(n) + (1-N) MHl/MHl/C, Hlsub(2(g)) where Hl is Cl, Br or I, M is Li, Na, K, Cs or Na + K, and N < 0.05, is measured as a function of concentration at several temperatures. Expressions are obtained for its concentration dependence. The emf grows in the series of alkali chlorides from LiCl to CsCl, other conditions being equal. (author)

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

    International Nuclear Information System (INIS)

    Tsuruta, T.

    2006-01-01

    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

  1. Fuel-cycle facilities: preliminary safety and environmental information document. Volume VII

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Information is presented concerning the mining and milling of uranium and thorium; uranium hexafluoride conversion; enrichment; fuel fabrication; reprocessing; storage options; waste disposal options; transportation; heavy-water-production facilities; and international fuel service centers.

  2. Fuel-cycle facilities: preliminary safety and environmental information document. Volume VII

    International Nuclear Information System (INIS)

    1980-01-01

    Information is presented concerning the mining and milling of uranium and thorium; uranium hexafluoride conversion; enrichment; fuel fabrication; reprocessing; storage options; waste disposal options; transportation; heavy-water-production facilities; and international fuel service centers

  3. Thorium Occurrences, Geological Deposits and Resources

    International Nuclear Information System (INIS)

    Barthel, F.H.; Tulsidas, H.

    2014-01-01

    Availability of Thorium: • Monazite production can be used as a measure for Th availability. • Without commercial rare earth requirements recovery of Th from monazite is not economic. • Extraction of Th from deposits containing e.g. Nb,Ta, may become economic by-product once commercial Th requirements progress.• Monazite is extracted in India, Brazil, Malaysia. • Annually 6 300 to 7 400 t monazite between 2004 and 2008. • Largest producer: India, ~5 000 t monazite /a. • Later figures are not available (Chinese competition on the rare earth market?). • Other monazite producers (unknown amounts): China, Indonesia, Nigeria, North and South Korea, CIS. • Theoretical content of Th in the above reported monazite: 300 to 600 t Th. • Th production reported: Brazil, Canada, India and others, details are not available.

  4. Toxicological profile for thorium. Draft report (Final)

    International Nuclear Information System (INIS)

    1990-10-01

    The ATSDR Toxicological Profile for Thorium is intended to characterize succinctly the toxicological and health effects information for the substance. It identifies and reviews the key literature that describes the substance's toxicological properties. Other literature is presented but described in less detail. The profile is not intended to be an exhaustive document; however, more comprehensive sources of specialty information are referenced. The profile begins with a public health statement, which describes in nontechnical language the substance's relevant toxicological properties. Following the statement is material that presents levels of significant human exposure and, where known, significant health effects. The adequacy of information to determine the substance's health effects is described. Research gaps in nontoxic and health effects information are described. Research gaps that are of significance to the protection of public health will be identified in a separate effort. The focus of the document is on health and toxicological information

  5. Thorium Molten-Salt Nuclear Energy Synergetics

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Lecocq, A.; Kato, Yoshio; Mitachi, Kohshi.

    1990-01-01

    In the next century, the 'fission breeder' concept will not be practical to solve the global energy problems, including environmental and North-South problems. As a new measure, a simple rational Th molten salt breeding fuel cycle system, named 'Thorium Molten-Salt Nuclear Energy Synergetics (THORIMS-NES)', which composed of simple power stations and fissile producers, is proposed. This is effective to establish the essential improvement in issues of resources, safety, power-size flexibility, anti-nuclear proliferation and terrorism, radiowaste, economy, etc. securing the simple operation, maintenance, chemical processing, and rational breeding fuel cycle. As examples, 155 MWe fuel self-sustaining power station 'FUJI-II', 7 MWe pilot-plant 'miniFUJI-II', 1 GeV-300 mA proton Accelerator Molten-Salt Breeder 'AMSB', and their combined fuel cycle system are explained. (author)

  6. Ultimate storage of thorium-bearing waste

    International Nuclear Information System (INIS)

    Ganser, B.

    1986-01-01

    The goal of this R and D project was to experimentally determine the release of the radioactive noble gas radon from thorium-bearing waste. For the experiments, three 200 litre waste forms have been prepared: One package consisting of inactive cement (for blank value determination), the second of cemented, radioactive sludge precipitate (for reference value determination), and the third of untreated sludge precipitate in a drum. The release rate measured on the reference package at room temperature is 3.1x10 10 Bq/a for Rn-220, and 2.4x10 6 Bq/a for Rn-222. The release rate from a drum under equal conditions is 4.1x10 8 Bq/a for Rn-220, and 2.1x10 6 Bq/a for Rn-222. (orig./RB) [de

  7. Parametric study of a thorium model

    International Nuclear Information System (INIS)

    Lourenco, M.C.; Lipztein, J.L.; Szwarcwald, C.L.

    1997-01-01

    Full text. Models for radionuclides distribution in the human body and dosimetry involve assumptions on the biokinetic behaviour of the material among compartments representing organs and tissues in the body. The lack of knowledge about the metabolic behaviour of a radionuclide represents a factor of uncertainty in estimates of committed dose equivalent. An important problem in biokinetic modeling is the correct assignment of transfer coefficients and biological half-lives to body compartments. The purpose of this study is to analyze the variability in the activities of the body compartments in relation to the variations in the transfer coefficients and compartments biological half-lives in a certain model. A thorium specific recycling model for continuous exposure was used. Multiple regression analysis methods were applied to analyze the results

  8. Nuclear calculation of the thorium reactor

    International Nuclear Information System (INIS)

    Hirakawa, Naohiro

    1998-01-01

    Even if for a reactor using thorium (and 233-U), its nuclear design calculation procedure is similar to the case using conventional 235-U, 238-U and plutonium. As nuclear composition varies with time on operation of nuclear reactor, calculation of its mean cross section should be conducted in details. At that time, one-group cross section obtained by integration over a whole of energy range is used for small member group. And, as the nuclear data for a base of its calculation is already prepared by JENDL3.2 and nuclear data library derived from it, the nuclear calculation of a nuclear reactor using thorium has no problem. From such a veiwpoint, IAEA has organized a coordinated research program of 'Potential of Th-based Fuel Cycles to Constrain Pu and to reduce Long-term Waste Toxicities' since 1996. All nations entering this program were regulated so as to institute by selecting a nuclear fuel cycle thinking better by each nation and to examine what cycle is expected by comparing their results. For a promise to conduct such neutral comparison, a comparison of bench mark calculations aiming at PWR was conducted to protect that the obtained results became different because of different calculation method and cross section adopted by each nation. Therefore, it was promoted by entrance of China, Germany, India, Israel, Japan, Korea, Russia and USA. The SWAT system developed by Tohoku University is used for its calculation code, by using which calculated results on the bench mark calculation at the fist and second stages and the nuclear reactor were reported. (G.K.)

  9. Spectrographic analysis of thorium and its compounds

    International Nuclear Information System (INIS)

    Grampurohit, S.V.; Saksena, M.D.; Kaimal, V.N.P.; Kapoor, S.K.; Murty, P.S.

    1980-01-01

    A spectrographic method, which employs the principle of carrier-distillation technique, is described for the analysis of high purity thoria. Two carriers, AgCl and NaF were used in determining 27 trace elements in ThO 2 . The elements were divided into three groups, A, B and C. In group A, 15 elements, viz. Al, B, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Si and Sn were included since it was possible to choose sensitive lines of these elements in one spectral region, 220 - 285 nm. Group B covered 8 elements, viz. Ag, Bi, Ca, Ga, Mo, Ti, V and Zn, which could be determined in the spectral region 290 - 352.5 nm. Group C consisted 4 elements, viz. Ba, K, Li and Na which could be determined in the spectral region 440 - 820 nm. 5% AgCl was used as the carrier for the determination of groups A and C elements and 4% NaF was used as the carrier for the estimation of group B elements. One hundred milligrammes of the sample (in the form of ThO 2 ) containing the carrier were taken in a carrier-distillation electrode and excited in a d.c. arc (10 amps for groups A and C; 15 amps for group B). The spectra of sample and synthetic standards were photographed on Hilger's large quartz, JACO 3.4 m Ebert plane grating and Higler's large glass spectrographs respectively for determining group A, B and C elements. The detection limit obtained for B and Cd was 0.1 ppm. Thorium metal and thorium nitrate samples were converted to ThO 2 prior to analysis. (auth.)

  10. Thor, a thorium-reflected plutonium-metal critical assembly

    International Nuclear Information System (INIS)

    Hansen, G.E.; Paxton, H.C.

    1979-01-01

    Critical specifications of Thor, an old assembly of thorium-reflected plutonium, have been refined. These specifications are brought together with void coefficients, Rossi-alpha values, fission traverses, and spectral indices

  11. Thorium contents in soils, vegetables, cereals, and fruits

    International Nuclear Information System (INIS)

    Frindik, O.

    1989-01-01

    Thorium contents (α-activities of the naturally occurring isotopes Th-228, Th-230, and Th-232) were detrmined in soils, vegetables, cereals, and fruits. The thorium content of plants depends on the degree of contamination by soil resuspension and thus on the specific surface of the plants. The activity of the isotope Th-230 is almost the same as that of the main isotope Th-232. Th-228, with about the same activity as Th-232 in soil, increases to about 10-fold the activity in vegetables, 29-fold in sweet chestnuts and 740-fold in Brazil nuts. Thorium concentration factors from the soil to these vegetable products are calculated; they include the total concentration, not only the soluble portion of thorium. (orig.) [de

  12. Spectral shift controlled reactors, denatured U-233/thorium cycle

    International Nuclear Information System (INIS)

    1978-05-01

    This paper presents technical and economic data on the SSCR which may be of use in the International Fuel Cycle Evaluation Program to intercompare alternative nuclear systems. Included in this paper are data on the denatured U-233/thorium cycle. This cycle shows a proliferation advantage over more classical thorium fuel cycle (e.g., highly-enriched U-235/thorium or plutonium/thorium) due to the elimination of chemically-separable, concentrated fissile material from unirradiated nuclear fuel. The U-233 is denatured by mixing with depleted uranium to a concentration no greater than 12 w/o. An exogenous source of U-233 is assumed in this paper, since U-233 does not occur in nature and only a limited supply has been produced to date for research and development work

  13. Study on Thorium Hidroxide and Ammonium Diuranate precipitation

    International Nuclear Information System (INIS)

    Damunir; Sukarsono, R; Busron-Masduki; Indra-Suryawan

    1996-01-01

    Thorium hydroxide and ammonium diuranate precipitation studied by the reaction of mixed thorium nitrate and uranyl nitrate using ammonium hydroxide. The purposes of this research was study of pH condition. U/Th ratio and NH 4 OH concentration on the precipitation. Mixed of thorium nitrate and uranyl nitrate 50 ml was reacted by excess ammonium hydroxide 2 - 10 M, pH 4-8, 40-80 o C of temperature and 5 - 100 % ratio of U/Th. The best of precipitation depend on thorium and uranium content on the precipitation. The experiment result for the best condition of precipitation was 25 % of ratio U/Th, pH 6 - 8, 60-80 o C of temperature, and 6 - 10 M concentration of ammonium hydroxide, was produced precipitate by 3,938 - 5,455 weight percent of mean concentration of U and 22,365-31,873 weight percent of mean concentration of Th

  14. Investigation of colourless complexes of thorium, hafnium and zirconium

    International Nuclear Information System (INIS)

    Kiciak, S.; Stefanowicz, T.; Gontarz, H.; Swit, Z.

    1980-01-01

    The investigations conducted in the Institute of General Chemistry of Poznan Technical University in partial cooperation with Kharkhof Technical University related with thorium, hafnium and zirconium complexes are reviewed. (author)

  15. Thorium, UNFC (3,3,3) In Brasil

    International Nuclear Information System (INIS)

    Villas-Bôas, Roberto C.

    2014-01-01

    Types of thorium UNFC (3,3,3) in Brasil: • Placer, shoreline; • Placer, alluvial; • Carbonatite with residual enrichment (Barreiro,Catalao); • Carbonatite (Salitre, MG); • Pitinga granites (AM); • Alkalic Igneous

  16. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Studies on biamperometric determination of thorium using EDTA as titrant

    International Nuclear Information System (INIS)

    Jayachandran, Kavitha; Nair, P.R.; Noronha, D.M.; Xavier, Mary; Aggarwal, S.K.

    2009-01-01

    A method is described for the determination of thorium at sub milligram levels by EDTA complexometric titration using biamperometric end point detection. The methodology is based on the electroactive behaviour of EDTA observed at pH 2-3, suggesting a reversible electron transfer reaction at potential ≥ 200 mV applied between twin Pt electrodes. Accuracy and precision of better than 2% were obtained for thorium amounts in the 100-500 μg range. (author)

  18. Integral benchmarks with reference to thorium fuel cycle

    International Nuclear Information System (INIS)

    Ganesan, S.

    2003-01-01

    This is a power point presentation about the Indian participation in the CRP 'Evaluated Data for the Thorium-Uranium fuel cycle'. The plans and scope of the Indian participation are to provide selected integral experimental benchmarks for nuclear data validation, including Indian Thorium burn up benchmarks, post-irradiation examination studies, comparison of basic evaluated data files and analysis of selected benchmarks for Th-U fuel cycle

  19. The use of thorium as an alternative nuclear fuel

    International Nuclear Information System (INIS)

    Wilson, D.J.

    1982-04-01

    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

  20. Assessment of the thorium fuel cycle in power reactors

    International Nuclear Information System (INIS)

    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

  1. Separation of Protactinium from Neutron Irradiated Thorium Oxide

    International Nuclear Information System (INIS)

    Dominguez, G.; Gutierrez, L.; Ropero, M.

    1983-01-01

    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 ThO 2 material into ThF 4 . 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

  2. Thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium

    International Nuclear Information System (INIS)

    Khamidov, F.A.; Mirsaidov, I.U.; Nazarov, K.M.; Nasriddinov, S.K.; Badalov, A.B.

    2010-01-01

    Present article is devoted to thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium. The results of researches of dehydration process of uranyl nitrate pentahydrate of thorium Th(NO_3)_4·5H_2O were considered. The researches were carried out by means of tensimeter method with membrane zero-manometer under equilibrium conditions and at 300-450 K temperature ranges. The thermodynamic characteristics of dehydration process of initial crystalline hydrate was defined.

  3. The cohesive energy of uranium dioxide and thorium dioxide

    International Nuclear Information System (INIS)

    Childs, B.G.

    1958-08-01

    Theoretical values have been calculated of the heats of formation of uranium dioxide and thorium dioxide on the assumption that the atomic binding forces in these solids are predominantly ionic in character. The good agreement found between the theoretical and observed values shows that the ionic model may, with care, be used in calculating the energies of defects in the uranium and thorium dioxide crystal structures. (author)

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

    International Nuclear Information System (INIS)

    Kamei, T.

    2012-01-01

    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 CO 2 . 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

  5. The comparative distribution of thorium and plutonium in human tissues

    International Nuclear Information System (INIS)

    Singh, Narayani P.; Shawki Amin Ibrahim; Cohen, Norman; Wrenn, McDonald E.

    1978-01-01

    Thorium is the most chemically and biologically similar natural element to the manmade element plutonium. Both are actinides, and for both the most stable valency state is +4, and solubility in natural body fluids is low. They are classified together in ICRP Lung Model. The present paper deals with the question of whether or not the analogy between the two actinides in terms of deposition and retention in human tissues is a good one. Preliminary results on the thorium contents ( 228,230 Th and 232 Th) of three sets of human tissues from a western U.S. town containing a uranium tailings pile are compared with the reported values of plutonium content of human tissues from the general populations who are exposed to environmental plutonium from fallout of nuclear detonations. Samples were taken at autopsy where sudden death had occurred. For the three isotopes of thorium, the ratio of the content of each (pCi/organ, normalized by organ weight to ICRP Reference Man) in lung to lymph nodes varies from 2-25 for individuals with a mean of 8; this is similar to that we infer from the literature for 239 , 240 Pu which suggests a ratio of lung to lymph nodes with a mean of approximately 7. However, the relative thorium contents of lung and liver are dissimilar, lung/liver for thorium being 3.5 and for plutonium 0.2 to 0.1. Similarly, the ratios of thorium and plutonium content of liver and bone vary significantly; the ratio for thorium is 0.1 and for plutonium 0.8 to 0.5. The most significant observation at this stage is that the relative accumulation of thorium in human liver is much less than that of plutonium. Some of the plausible reasons will be discussed. (author)

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

    International Nuclear Information System (INIS)

    Joo, Hyung Kook; Noh, Jae Man; Yoo, Jae Woon

    2001-01-01

    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

  7. Thorium fuels for heavy water reactors. Romanian experience

    International Nuclear Information System (INIS)

    Glodeanu, F.; Mirion, I.; Mehedinteanu, S.; Balan, V.

    1984-01-01

    The renewed interest in thorium fuel cycle due to the increased demand for fissile materials has resulted in speeding up the related research and development activities. For heavy water reactors the thorium cycles, especially SSET, are very promising and many efforts are made to demonstrate their feasibility. In our country, at INPR, the research and development activity has been initiated in the following areas: the conceptual design of thorium bearing fuel elements; fuel modelling; nuclear grade thorium dioxide powder technology; mixed oxide fuel technology. In the design area, the key factors in performance limitation, especially at extended burnup have been accounted and different remedies proposed. An irradiation programme has been settled and will start this year. The modelling activities are focused on mixed oxide behaviour and material data measurements are in progress. In the nuclear grade thorium powder technology area, a good piece of work has been done to develop an integrated technology for monasite processing (thorium being a by-product in lanthanides extraction). As regards the mixed oxide fuel technology, efforts have been made to obtain (ThU)O 2 pellets with good homogeneity and high density at different compositions. Besides the mixing powders route, other non-conventional technologies for refabrication like: microspheres, pellet impregnation and clay extrusion are studied. Experimental fuel rods for irradiation testing have been manufactured. (author)

  8. Evaluation of thorium based nuclear fuel. Extended summary

    International Nuclear Information System (INIS)

    Franken, W.M.P.; Bultman, J.H.; Konings, R.J.M.; Wichers, V.A.

    1995-04-01

    Application of thorium based nuclear fuels has been evaluated with emphasis on possible reduction of the actinide waste. As a result three ECN-reports are published, discussing in detail: - The reactor physics aspects, by comparing the operation characteristics of the cores of Pressurized Water Reactors and Heavy Water Reactors with different fuel types, including equilibrium thorium/uranium free, once-through uranium fuel and equilibrium uranium/plutonium fuel, - the chemical aspects of thorium based fuel cycles with emphasis on fuel (re)fabrication and fuel reprocessing, - the possible reduction in actinide waste as analysed for Heavy Water Reactors with various types of thorium based fuels in once-through operation and with reprocessing. These results are summarized in this report together with a short discussion on non-proliferation and uranium resource utilization. It has been concluded that a substantial reduction of actinide radiotoxicity of the disposed waste may be achieved by using thorium based fuels, if very efficient partitioning and multiple recycling of uranium and thorium can be realized. This will, however, require large efforts to develop the technology to the necessary industrial scale of operation. (orig.)

  9. Dynamic Analysis of the Thorium Fuel Cycle in CANDU Reactors

    International Nuclear Information System (INIS)

    Jeong, Chang Joon; Park, Chang Je

    2006-02-01

    The thorium fuel recycle scenarios through the Canada deuterium uranium (CANDU) reactor have been analyzed for two types of thorium fuel: homogeneous ThO 2 UO 2 and ThO 2 UO 2 -DUPIC fuels. The recycling is performed through the dry process fuel technology which has a proliferation resistance. For the once-through fuel cycle model, the existing nuclear power plant construction plan was considered up to 2016, while the nuclear demand growth rate from the year 2016 was assumed to be 0%. After setting up the once-through fuel cycle model, the thorium fuel CANDU reactor was modeled to investigate the fuel cycle parameters. In this analysis, the spent fuel inventory as well as the amount of plutonium, minor actinides and fission products of the multiple recycling fuel cycle were estimated and compared to those of the once-through fuel cycle. From the analysis results, it was found that the closed or partially closed thorium fuel cycle can be constructed through the dry process technology. Also, it is known that both the homogeneous and heterogeneous thorium fuel cycles can reduce the SF accumulation and save the natural uranium resource compared with the once-through cycle. From the material balance view point, the heterogeneous thorium fuel cycle seems to be more feasible. It is recommended, however, the economic analysis should be performed in future

  10. The possibility of precipitating thorium soap from aqueous solutions

    International Nuclear Information System (INIS)

    Drathen, H.

    1975-01-01

    The purpose of the analysis was firstly to determine the precipitation process of thorium with soap and the influence of foreign ions, secondly to explain the conditions for the best method of decontaminating waste waters contaminated by thoriuum. The result was that if thorium is precipitated with soap both thorium soaps and thorium hydroxide are formed. The proportion of each substance depends considerably upon the pH value. All the precipitation compounds exist independently. No adsorption or mixed crystal formation took place. By adding bivalent or multivalent cations the one-step decontamination factor increases to more than 20. Quantitatively, the decontamination of thorium contaminated waste waters can be carried out down to a thorium concentration of 10 -5 mol/1. Technical soaps provide the least expensive solution without displaying any qualitative disadvantages. The only disadvantage is that this method cannot be used continuously. Therefore ion exchangers provide a great advantage, although they are very expensive and have a limited capacity. The best solution, then, is a combination of ion exchangers and precipitation with soap. (orig.) [de

  11. Dynamic Analysis of the Thorium Fuel Cycle in CANDU Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Chang Joon; Park, Chang Je

    2006-02-15

    The thorium fuel recycle scenarios through the Canada deuterium uranium (CANDU) reactor have been analyzed for two types of thorium fuel: homogeneous ThO{sub 2}UO{sub 2} and ThO{sub 2}UO{sub 2}-DUPIC fuels. The recycling is performed through the dry process fuel technology which has a proliferation resistance. For the once-through fuel cycle model, the existing nuclear power plant construction plan was considered up to 2016, while the nuclear demand growth rate from the year 2016 was assumed to be 0%. After setting up the once-through fuel cycle model, the thorium fuel CANDU reactor was modeled to investigate the fuel cycle parameters. In this analysis, the spent fuel inventory as well as the amount of plutonium, minor actinides and fission products of the multiple recycling fuel cycle were estimated and compared to those of the once-through fuel cycle. From the analysis results, it was found that the closed or partially closed thorium fuel cycle can be constructed through the dry process technology. Also, it is known that both the homogeneous and heterogeneous thorium fuel cycles can reduce the SF accumulation and save the natural uranium resource compared with the once-through cycle. From the material balance view point, the heterogeneous thorium fuel cycle seems to be more feasible. It is recommended, however, the economic analysis should be performed in future.

  12. Survey of thorium utilization in power reactor systems

    International Nuclear Information System (INIS)

    Schwartz, M.H.; Schleifer, P.; Dahlberg, R.C.

    1976-01-01

    It is clear that thorium-fueled thermal power reactor systems based on current technology can play a vital role in serving present and long-term energy needs. Advanced thorium converters and thermal breeders can provide an expanded resource base from which the world's growing energy demands can be met. Utilization of a symbiotic system of fast breeders and thorium-fueled thermal reactors can be particularly effective in providing low cost power while conserving uranium resources. Breeder reactors are characterized by high capital costs and very low fuel costs since they produce more fuel than they consume. This excess fuel can be used to fuel thermal converter reactors whose capital costs are low. This symbiosis is optimized when 233 U is bred in the fast breeders and then used to fuel high-conversion-ratio thermal converter reactors operating on the thorium-uranium fuel cycle. The thorium-cycle HTGR, after undergoing more than fifteen years of development in both the United States and Europe, provides for the optimum utilization of our limited uranium resources. Other thermal reactor systems, previously operating on the uranium cycle, also show potential in their capability to utilize the thorium cycle effectively

  13. Neutronics assessment of thorium-based fuel assembly in SCWR

    International Nuclear Information System (INIS)

    Liu, Shichang; Cai, Jiejin

    2013-01-01

    Highlights: • A novel thorium-based fuel assembly for SCWR has been introduced and investigated. • Neutronic properties of three thorium fuels have been studied, compared with UO 2 fuel. • The thorium-based fuel has advantages on fuel utilization and lower MAs generation. -- Abstract: Aiming to take advantage of neutron spectrum of SCWR, a novel thorium-based fuel assembly for SCWR is introduced in this paper. The neutronic characteristics of the introduced fuel assembly with three different thorium fuel types have been investigated using the “dragon” codes. The parameters in different working conditions, such as infinite multiplication factors, radial power peaking factor, temperature coefficient of reactivity and their relation with the operation period have been assessed by comparing with conventional uranium assembly. Moreover, the moderator-to-fuel ratio (MFR) was changed in order to investigate its influence on the neutronic characteristics of fuel assembly. Results show that the thorium-based fuel has advantages on both efficient fuel utilization and lower minor actinide generation, with some similar neutronic properties to the uranium fuel

  14. 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

  15. Thorium as an energy source. Opportunities for Norway

    International Nuclear Information System (INIS)

    2008-01-01

    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

  16. 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.

  17. Potential for the near-term use of the thorium cycle in a sustainable way

    International Nuclear Information System (INIS)

    Wider, H.; Tucek, K.; Carlsson, J.

    2007-01-01

    Nuclear sustainability is generally believed to be only reachable through the building of many fast breeder reactors. This paper shows that there is another possibility by using existing reactors that are either thermal breeders or have at least a high conversion ratio and considerably smaller critical masses than fast systems. Earlier it was believed that thermal molten salt breeders could eventually use the thorium / 233U cycle, which doesn't generate minor actinides and is therefore a cleaner fuel cycle. In the meantime, it has become rather clear that CANDU reactors that use heavy water cooling can also be self-breeders. The CANDU reactors could generate themselves 233U in thorium targets and could become selfsustaining after 12 years. However, additional 233U could also be generated in LWRs and fast reactors. It is shown that this generation of 233U will allow a faster large-term nuclear expansion than fast reactors alone. There could actually be a synergy between thermal and fast breeders if the latter are run with Pu/Minor Actinides/Th fuel, which burns the minor actinides and generates sizeable amounts of 233U. The main problem is still the necessary reprocessing on which India is working and intends to have in 10 years a large scale reprocessing facility available. However, there is at least an existing method for removing the 233U by the fluoride volatility method and to further use it in CANDUs. For the preparation of the use of 233U, we should attempt to run thorium subassemblies in CANDUs, LWRs, and fast reactors. Besides breeding 233U or at least having a high conversion ratio, CANDUs have the further advantage that they don't need a pressure vessel and therefore could be built in large numbers faster than LWRs. (author)

  18. Binary and ternary photofission of thorium 232

    Energy Technology Data Exchange (ETDEWEB)

    Titterton, E W; Brinkley, T A

    1950-05-01

    Work by Titterton and Goward (1949) has shown that uranium undergoes photofission into three charged fragments. Experiments have been conducted to determine whether a similar process takes place in the photofission of thorium. Some difficulties were encountered in loading plates with /sup 232/Th atoms, but this was finally accomplished by means of a technique described in detail. Plates loaded by this method were irradiated with a continuous spectrum of ..gamma.. rays of maximum energy 24 MeV from the (Atomic Energy Research Establishment) Synchrotron. Three irradiations, of 100, 150, and 180 r, were made and the resulting plates showed a fission density of 2.5 x 10/sup 4//cc at the 150 r level. In an examination involving 2500 binary photofissions, 5 cases of ternary fission involving the emission of a long range light fragment, probably an ..cap alpha..-particle, were observed. These events are described. A number-range curve was determined for the photofission tracks and is compared with a similar curve for tracks formed by the slow neutron fission of /sup 235/U in a D/sub 1/ emulsion under conditions of similar emulsion sensitivity. It appears that the energy release in the photofission of /sup 232/Th is smaller than that in the slow neutron fission of /sup 235/U. The data indicate that 124 MeV is the mean kinetic energy released in the photofission of /sup 232/Th.

  19. Uranium and thorium migration under dislocative metamorphism

    International Nuclear Information System (INIS)

    Titov, V.K.; Bilibina, T.V.; Dashkova, A.D.; Il'in, V.K.; Makarova, L.I.; Shmuraeva, L.Ya.

    1978-01-01

    Investigated were peculiarities of uranium and thorium behaviour in the process of dislocation metamorphism on the basis of regional fracture zones of early-proterozoic embedding of Ukrainian, Aldan and Baltic shields. The studied zones correspond to tectonite of green-shale and almandin-amphibolite facies of regional metamorphism according to mineral associations. The most peculiar feature of the tectonites of green-shale facies is uranium presence in migrationally able forms, which can be involved afterwards into the ore process by hydrothermal solutions. Adsorved forms of uranium on the crystal surface or separate grains and in the cracks, as well as microinclusions of uranium minerals, selectively timed to mineral structure defects prevail among easily mobile uranium compounds. Dissolved uranium is present, evidently in gas-liquid inclusions in minerals and pore waters. There forms of uranium presence are peculiar for epidote-chlorite mylonites, as well as cataclasites and diaphthorites related to them by blastomylonites of almandin-amphibolite facies. Wide range of manifestation of this process, caused by multikilometer extension of deep fracture zones permit to consider the formations of green-shale facies of dislocation metamorphism as one of the main uranium sources in deposit formation in different uranium-ore associations different age

  20. Air/Water Purification

    Science.gov (United States)

    1992-01-01

    After 18 years of research into air/water pollution at Stennis Space Center, Dr. B. C. Wolverton formed his own company, Wolverton Environmental Services, Inc., to provide technology and consultation in air and water treatment. Common houseplants are used to absorb potentially harmful materials from bathrooms and kitchens. The plants are fertilized, air is purified, and wastewater is converted to clean water. More than 100 U.S. communities have adopted Wolverton's earlier water hyacinth and artificial marsh applications. Catfish farmers are currently evaluating the artificial marsh technology as a purification system.

  1. Water Purification Product

    Science.gov (United States)

    2004-01-01

    Ecomaster, an affiliate of BioServe Space Technologies, this PentaPure technology has been used to purify water for our nation's Space Shuttle missions since 1981. WTC-Ecomaster of Mirneapolis, Minnesota manufactures water purification systems under the brand name PentaPure (TM). BioServe researcher Dr. George Marchin, of Kansas State University, first demonstrated the superiority of this technology and licensed it to WTC. Marchin continues to perform microgravity research in the development of new technologies for the benefit of life on Earth.

  2. Gas purification project

    International Nuclear Information System (INIS)

    Broothaerts, J.; Claes, J.; Collard, G.; Goossens, W.; Harnie, R.; Heylen, P.; Vaesen, J.; Beukelaer, R. de; Dubois, G.; Glibert, R.; Mestrez, J.; Zahlen, A.

    1975-06-01

    Conceptual and experimental studies on LMFBR reprocessing and reactor off-gas purification systems are summarized. Iodine sorption on zeolites, low-temperature adsorption of noble gases on charcoal and catalytic oxidation of hydrogen, simulating tritium, are being studied in laboratory set-ups. A pilot loop with 25 m 3 h -1 throughput has been constructed. Results are quoted from the first phase of the iodine removal programme by scrubbing systems. Further extension of the test loop, comprising off-gases conditioning to removal of krypton in a cryodistillation unit, has been prepared. Delay-bed studies on 133 Xe extraction from LWR off-gases are reported. (author)

  3. Thorium based fuel options for the generation of electricity: Developments in the 1990s

    International Nuclear Information System (INIS)

    2000-05-01

    The IAEA has maintained an interest in the thorium fuel cycle and its worldwide utilization within its framework of activities. Periodic reviews have assessed the current status of this fuel cycle, worldwide applications, economic benefits, and perceived advantages with respect to other nuclear fuel cycles. Since 1994, the IAEA convened a number of technical meetings on the thorium fuel cycle and related issues. Between 1995 and 1997 individual contributions on the thorium fuel cycle were elicited from experts from France, Germany, India, Japan, the Russian Federation and the USA. These contributions included evaluations of the status of the thorium fuel cycle worldwide; the new incentives to use thorium due to large stockpiles of plutonium produced in nuclear reactors; new reactor concepts utilizing thorium; strategies for thorium use; and an evaluation of toxicity of the thorium fuel cycle waste compared to that from other fuel cycles. The results of this updated evaluation are summarized in this publication

  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. The thorium alloys in aeronautics: from material analysis to regulation application

    International Nuclear Information System (INIS)

    Laroche, P.; Cazoulat, A.; Gerasimo, P.

    1999-01-01

    The thorium handled in aeronautics is a mixing in variable proportion of different thorium isotopes and its daughter products, but the regulation considers only two alpha emitters (Th-232 and Th-228): the thorium being considered as a natural radioactive substance, the legislation and the activities authorised are less restrictive than for artificial elements, it is a paradoxical situation because the thorium has the annual limit of intake the lowest of the regulation. (N.C.)

  6. Simulating evaporation of surface atoms of thorium-alloyed tungsten in strong electronic fields

    International Nuclear Information System (INIS)

    Bochkanov, P.V.; Mordyuk, V.S.; Ivanov, Yu.I.

    1984-01-01

    By the Monte Carlo method simulating evaporation of surface atoms of thorium - alloyed tungsten in strong electric fields is realized. The strongest evaporation of surface atoms of pure tungsten as compared with thorium-alloyed tungsten in the contentration range of thorium atoms in tungsten matrix (1.5-15%) is shown. The evaporation rate increases with thorium atoms concentration. Determined is in relative units the surface atoms evaporation rate depending on surface temperature and electric field stront

  7. Effect of charcoal on water purification

    OpenAIRE

    Suzuki, Hirotaka; Kawahigashi, Tatsuo

    2014-01-01

    [Abstract] A natural basin system purifies water through self-purification, but the water pollution load of a river might exceed its self-purification capacity. Charcoal, which is used for other uses aside from heating, such as air purification, was evaluated experimentally for water quality purification. The experiment described herein is based on simple water quality measurements. Some experimentally obtained results are discussed.

  8. Statistical and Judgmental Criteria for Scale Purification

    DEFF Research Database (Denmark)

    Wieland, Andreas; Durach, Christian F.; Kembro, Joakim

    2017-01-01

    of scale purification, to critically analyze the current state of scale purification in supply chain management (SCM) research and to provide suggestions for advancing the scale-purification process. Design/methodology/approach A framework for making scale-purification decisions is developed and used...

  9. Cementation feasibility of a uranium-thorium based solution by physical and mechanical characterization

    International Nuclear Information System (INIS)

    Carpentiero, R.; Luce, A.; Troiani, F.

    2002-01-01

    By reprocessing Elk River nuclear fuel, at the ENEA ITREC Plant (South of Italy), about 3 m 3 of Uranium-Thorium based solution were produced. Previously considered an intermediate product to be further treated to recover U and Th, it is now being considered a waste, due to considerable content of fission products and to phasing out of the Italian nuclear industry. Together with other treatment options, a conditioning process in cement matrix is being evaluated, supported by some chemical, physical and mechanical tests on samples prepared with simulated waste. The main components selected to simulate the real solution were thorium nitrate (at two different concentrations), ferrous nitrate and nitric acid. This solution has been neutralized with sodium carbonate (at two different concentration) and cemented by means of a properly defined formulation. Pozzolanic blend cement, at different water to cement ratio, with and without a silica type additive, has been investigated. Cubic samples were subjected to compression tests and repeated freeze-thaw cycles followed by compression tests. Cylindrical samples were subjected to a leach test (according. to the tn ANSI/ANS-16.1 standard). The obtained results are above the minimum acceptance values established by the Italian authority. The evaluated properties are the first important elements to estimate the long term-instability of conditioned radioactive waste. Meanwhile a preliminary theoretical study has been done to evaluate the gas evolution from the matrix due to radiolysis effect. The reached conclusions encourage the development of further analysis to implement a cementation facility. (Author)

  10. Laser-induced breakdown spectroscopy measurements of uranium and thorium powders and uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Judge, Elizabeth J. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, James E., E-mail: jbarefield@lanl.gov [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Berg, John M. [Manufacturing Engineering and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, Samuel M.; Havrilla, George J.; Montoya, Velma M.; Le, Loan A.; Lopez, Leon N. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-05-01

    Laser-induced breakdown spectroscopy (LIBS) was used to analyze depleted uranium and thorium oxide powders and uranium ore as a potential rapid in situ analysis technique in nuclear production facilities, environmental sampling, and in-field forensic applications. Material such as pressed pellets and metals, has been extensively studied using LIBS due to the high density of the material and more stable laser-induced plasma formation. Powders, on the other hand, are difficult to analyze using LIBS since ejection and removal of the powder occur in the laser interaction region. The capability of analyzing powders is important in allowing for rapid analysis of suspicious materials, environmental samples, or trace contamination on surfaces since it most closely represents field samples (soil, small particles, debris etc.). The rapid, in situ analysis of samples, including nuclear materials, also reduces costs in sample collection, transportation, sample preparation, and analysis time. Here we demonstrate the detection of actinides in oxide powders and within a uranium ore sample as both pressed pellets and powders on carbon adhesive discs for spectral comparison. The acquired LIBS spectra for both forms of the samples differ in overall intensity but yield a similar distribution of atomic emission spectral lines. - Highlights: • LIBS analysis of mixed actinide samples: depleted uranium oxide and thorium oxide • LIBS analysis of actinide samples in powder form on carbon adhesive discs • Detection of uranium in a complex matrix (uranium ore) as a precursor to analyzing uranium in environmental samples.

  11. Separation of thorium from cerium by the ion-exchange sorption method. Pt. 3

    International Nuclear Information System (INIS)

    Sozanski, A.

    1981-01-01

    The method is described of separation of trace-quantities of thorium from chloride and ceric sulfate solutions. Thorium is sorbed selectively on the ion exchanger chelating Vofatite MC-50. Thorium-free ceric solutions were achieved and after ionite eluation concentrates of oxides were considerably enriched. (author)

  12. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Science.gov (United States)

    2010-10-01

    ... outer surface of the uranium or thorium is enclosed in an inactive sheath made of metal or other durable... 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...

  13. Performance of a 229Thorium solid-state nuclear clock

    International Nuclear Information System (INIS)

    Kazakov, G A; Schreitl, M; Winkler, G; Schumm, T; Litvinov, A N; Romanenko, V I; Yatsenko, L P; Romanenko, A V

    2012-01-01

    The 7.8 eV nuclear isomer transition in 229 thorium has been suggested as a clock transition in a new type of optical frequency standard. Here we discuss the construction of a ‘solid-state nuclear clock’ from thorium nuclei implanted into single crystals transparent in the vacuum ultraviolet range. We investigate crystal-induced line shifts and broadening effects for the specific system of calcium fluoride. At liquid nitrogen temperatures, the clock performance will be limited by decoherence due to magnetic coupling of the thorium nuclei to neighboring nuclear moments, ruling out the commonly used Rabi or Ramsey interrogation schemes. We propose clock stabilization based on a fluorescence spectroscopy method and present optimized operation parameters. Taking advantage of the large number of quantum oscillators under continuous interrogation, a fractional instability level of 10 −19 might be reached within the solid-state approach. (paper)

  14. Thorium Nitrate Stockpile--From Here to Eternity

    International Nuclear Information System (INIS)

    Hermes, W. H.; Hylton, T. D.; Mattus, C.H.; Storch, S. N.; Singley, P.S.; Terry, J. W.; Pecullan, M.; Reilly, F. K.

    2003-01-01

    The Defense National Stockpile Center (DNSC), a field level activity of the Defense Logistics Agency (DLA) has stewardship of a stockpile of thorium nitrate that has been in storage for decades. The stockpile is made up of approximately 3.2 million kg (7 million lb) of thorium nitrate crystals (hydrate form) stored at two depot locations in the United States. DNSC sought technical assistance from Oak Ridge National Laboratory (ORNL) to define and quantify the management options for the thorium nitrate stockpile. This paper describes methodologies and results comprising the work in Phase 1 and Phase 2. The results allow the DNSC to structure and schedule needed tasks to ensure continued safe long-term storage and/or phased disposal of the stockpile

  15. Recovery of Ra-223 from natural thorium irradiated by protons

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, Aleksandr N.; Ostapenko, Valentina S. [Lomonosov Moscow State Univ. (Russian Federation); Russian Academy of Sciences, Moscow-Troitsk (Russian Federation). Inst. for Nuclear Research; Lapshina, Elena V.; Ermolaev, Stanislav V.; Zhuikov, Boris L. [Russian Academy of Sciences, Moscow-Troitsk (Russian Federation). Inst. for Nuclear Research; Danilov, Sergey S. [Lomonosov Moscow State Univ. (Russian Federation); Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation); National Research Center ' Kurchatov Institute' (NRC ' Kurchatov Institute' ), Moscow (Russian Federation)

    2016-11-01

    Irradiation of natural thorium with medium-energy protons is considered to be a prospective approach to large-scale production of {sup 225}Ac and {sup 223}Ra. In addition to the earlier-developed method of {sup 225}Ac isolation, the present work focuses on the simultaneous recovery of {sup 223}Ra from the same thorium target. Radiochemical procedure is based on liquid-liquid extraction, cation exchange and extraction chromatography. The procedure provides separation of radium from spallation and fission products generated in the thorium target. High chemical yield (85-90%) and radionuclide purity of {sup 223}Ra (> 99.8% except {sup 224}Ra and {sup 225}Ra isotopes) have been achieved.

  16. Gold, uranium and thorium in zones of greenschist displacement metamorphism

    International Nuclear Information System (INIS)

    Gavrilenko, B.V.; Savitskij, A.V.; Titov, V.V.

    1987-01-01

    Distribution of gold, uranium (bar and mobile) and thorium in 15 zones of greenschist dislocated metamorphism in different structures of the Karelo-Kola region carried out by geologic formations of the Early-Archean-Late-Proterozoic age has been studied. More than 200 samples of well core from 0-200 m depths have been analyzed. The results obtained testify to the increase of gold, uranium and less thorium content in zones of green-schist dislocated metamorphism in comparison with the enclosing rocks 1.4-3.1 times. The variation coefficient of gold, uranium and thorium content in green-schist dislocated tectonites increases 1.5-2.9 times. The correlation coefficient of Au/U mob. pair is +0.69, and Au/U bar pair -+0.87. Essential correlation between concentrations of all three elements in enclosing rocks is absent

  17. DH-1a: a certified uranium-thorium reference ore

    International Nuclear Information System (INIS)

    Steger, H.F.; Bowman, W.S.; Zechanowitsch, G.

    1981-09-01

    A 122-kg sample of uranium-thorium ore, DH-1a, from Elliot Lake, Ontario, was prepared as a compositional reference material to replace the similar certified ore, DH-1. DH-1a was ground to minus 74μm, blended in one lot, and bottled in 200 g units. The homogeneity of DH-1a with respect to uranium was confirmed using the volumetric umpire method. The recommended value for uranium is based on the data from the confirmation of homogeneity. For thorium, twelve laboratories provided results in a free choice analytical program. A statistical analysis of the data gave a recommended value of 0.263 percent for uranium and 0.091 percent for thorium

  18. Determination of rare earth impurities in thorium by spectrographic methods

    Energy Technology Data Exchange (ETDEWEB)

    Wray, L W

    1957-08-15

    A method for determining rare earth impurities in thorium in the fractional ppm range is described. Before spectrographic examination is possible, the impurities must be freed from the thorium matrix. This is accomplished by removing the bulk of the thorium by extraction with TBP-CCl{sub 4} and the remainder by extraction with TTA-C{sub 6}H{sub 6}. This results in a consistent recovery of rare earths of about 85% with an average sensitivity of 0.2 ppm. The experimental error is within 10%. Details of the procedure are given together with working curves for the major neutron absorbing rare earths; i.e. dysprosium, europium, gadolinium and samarium. (author)

  19. Investigation of Pharmaceutical Residues in Hospital Effluents, in Ground- and Drinking Water from Bundeswehr Facilities, and their Removal During Drinking Water Purification (Arzneimittelrueckstaende in Trinkwasser(versorgungsanlagen) und Krankenhausabwaessern der Bundeswehr: Methodenentwicklung - Verkommen - Wasseraufbereitung)

    National Research Council Canada - National Science Library

    Heberer, Th; Feldmann, Dirk; Adam, Marc; Reddersen, Kirsten

    1999-01-01

    ... by the German Ministry of Defense. The project had three defined objectives including the investigation of pharmaceutical residues in ground water wells used for drinking water supply at military facilities...

  20. Physicochemical studies as thorium soaps in solid state

    International Nuclear Information System (INIS)

    Mehrotra, K.N.; Gahlaut, A.S.; Sharma, M.

    1987-01-01

    The thermal decomposition of thorium soaps is kinetically of zero order and the energy of activation for the decomposition process lies in the range of 6-11 kcal mol -1 . Infrared spectral data indicate that the fatty acids exist with dimeric structure through hydrogen bonding between the carboxyl groups of acid molecules whereas the metal soaps have an ionic character. The X-ray diffraction studies of these soaps revealed that thorium soaps have double layer structure with molecular axes slightly inclined to the basal plane. (author). 10 refs., 5 figures

  1. Once-through thorium cycles in Candu reactors

    International Nuclear Information System (INIS)

    Milgram, M.S.

    1982-01-01

    In once-through thorium cycles pure thorium fuel bundles can be irradiated conjointly with uranium fuel bundles in a CANDU reactor with parameters judiciously chosen such that the overall fuel cycle cost is competitive with other possibilities - notably low-enriched uranium. Uranium 233 can be created and stockpiled for possible future use with no imperative that it be used unless future conditions warrant, and a stockpile can be begun independently of the state of reprocessing technology. The existence and general properties of these cycles are discussed

  2. Study of thorium internal monitoring program by radiotoxicological analysis

    International Nuclear Information System (INIS)

    Gaburo, J.; Sordi, G.-M.A.A.

    1986-01-01

    The aim of this work is the establishment of a bioassay routine monitoring program for thorium occupationally exposed personnel. A simple and economic method for the analytical determination of the concentration of Th-232 in excreta samples was adopted, using Th-229 as a tracer. The mean yield of the method was 80%. Thorium concentration in excreta samples of non occupationally exposed Rio de Janeiro and Sao Paulo inhabitants was compared with data provenient from Nuclemon workers, with a exposition history to the nuclide of more than ten years and from IPEN workers only recently occupationally exposed to the nuclide. (Author) [pt

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

    International Nuclear Information System (INIS)

    Melo Ferreira, A.C. de.

    1989-01-01

    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 F 3 (Th), coupled to Makrofol detectors, were irradiated in the core of a research reactor, IEA-R1 (IPEN). (author)

  4. Atomization of thorium in a hollow-cathode type discharge

    International Nuclear Information System (INIS)

    Pianarosa, P.; Demers, Y.; Gagne, J.M.

    1984-01-01

    The atomization of thorium metal in a hollow-cathode electrical discharge has been investigated. Laser absorption spectroscopy with the laser tuned on the 5760.55 A (0-17355 1 cm -1 ) transition of Th I was used to evaluate the density of atoms in the 3 F 2 ground state. The results obtained (densities up to 10 13 atoms cm -3 ) show that our discharge tube is a suitable source of thorium metal atoms for laser assisted spectroscopic analysis of this element. (author)

  5. Future of antibody purification.

    Science.gov (United States)

    Low, Duncan; O'Leary, Rhona; Pujar, Narahari S

    2007-03-15

    Antibody purification seems to be safely ensconced in a platform, now well-established by way of multiple commercialized antibody processes. However, natural evolution compels us to peer into the future. This is driven not only by a large, projected increase in the number of antibody therapies, but also by dramatic improvements in upstream productivity, and process economics. Although disruptive technologies have yet escaped downstream processes, evolution of the so-called platform is already evident in antibody processes in late-stage development. Here we perform a wide survey of technologies that are competing to be part of that platform, and provide our [inherently dangerous] assessment of those that have the most promise.

  6. Optimization of thorium oxalate precipitation conditions relative to thorium oxide sinterability

    International Nuclear Information System (INIS)

    White, G.D.; Bray, L.A.; Hart, P.E.

    1980-01-01

    The effect of thorium oxalate precipitation conditions on derived oxide sinterability was investigated with the objective of producing ThO 2 powder that could be sintered to high density without premilling. Precipitation conditions examined were temperature, digestion time and agitation method which were employed in a two-level factorial experimental design to delineate their effects. The two levels for each of the factors, respectively, were 10 0 C and 70 0 C, 15 min and 360 min, and mechanical stirrer and a homogenizer that imparted both mechanical and ultrasonic agitation. The ThO 2 derived from each of the precipitation trials was characterized with respect to morphology, surface area, and crystallite size as well as sinterability. Only precipitation temperature had a significant effect upon all the properties of the derived oxide powders

  7. The uranium and thorium separation in the chemical reprocessing of the irradiated fuel of thorium and uranium mixed oxides

    International Nuclear Information System (INIS)

    Oliveira, E.F. de.

    1984-09-01

    A bibliographic research has been carried out for reprocessing techniques of irradiated thorium fuel from nuclear reactors. The Thorex/Hoechst process has been specially considered to establish a method for reprocessing thorium-uranium fuel from PWR. After a series of cold tests performed in laboratory it was possible to set the behavior of several parameters affecting the Thorex/Hoechst process. Some comments and suggestions are presented for modifications in the process flosheet conditions. A discussion is carried out for operational conditions such as the aqueous to organic flow ratio the acidity of strip and scrub solutions in the process steps for thorium and uranium recovery. The operation diagrams have been constructed using equilibrium experimental data which correspond to conditions observed in laboratory. (Author) [pt

  8. A thorium breeder reactor concept for optimal energy extraction from uranium and thorium

    International Nuclear Information System (INIS)

    Jagannnathan, V.; Lawande, S.V.

    1999-01-01

    An attractive thorium breeder reactor concept has been evolved from simple physics based guidelines for induction of thorium in a major way in an otherwise enriched uranium reactor. D 2 O moderator helps to maximise reactivity for a given enrichment. A relatively higher flux level compared to LWRs offers the advantage of higher rate of 233 U production in thoria rods. Thus fresh thoria clusters consider no feed enrichment. In an equilibrium core, a full batch of pure thoria clusters are loaded during each fuel cycle. They undergo irradiation for about one year duration. By this time they accumulate nearly 70% of the asymptotic stable concentration of 233 U, if they face a flux level of the order of 10 14 n/cm 2 /sec. In the next fuel cycle, these thoria rods in ring cluster form are juxtaposed with the fresh enriched fuel rods, also in ring cluster form. Such integrated fuel assemblies are then irradiated for four or five fuel cycles, at the end of which U as well as Th rods attain a reasonably high burnup of about 30-32 MWD/kg. The core characteristics are quite attractive. The core excess reactivity remains low due to large thoria inventory which makes the net burnup reactivity load to be below 1%. The core is capable of being operated in an annual batch mode of operation like a LWR. The control requirement during power operation is negligible. Xenon over-ride requirement is low and can be managed by partial withdrawal of a few thoria clusters. Void reactivity is nearly zero or negative by the optimum design of the fuel cluster. Reactivity changes due to temperatures of fuel, coolant and moderator are also small. (author)

  9. Feasibility and desirability of employing the thorium fuel cycle for power generation - 254

    International Nuclear Information System (INIS)

    Sehgal, B.R.

    2010-01-01

    Thorium fuel cycle for nuclear power generation has been considered since the very start of the nuclear power era. In spite of a very large amount of research, experimentation, pilot scale and prototypic scale installations, the thorium fuel was not adopted for large scale power generation [1,2]. This paper reviews the developments over the years on the front and the back-end of the thorium fuel cycle and describes the pros and cons of employing the thorium fuel cycle for large generation of nuclear power. It examines the feasibility and desirability of employing the thorium fuel cycle in concert with the uranium fuel cycle for power generation. (authors)

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

    International Nuclear Information System (INIS)

    Allibert, M.; Merle-Lucotte, E.; Ghetta, V.; Ault, T.; Krahn, S.; Wymer, R.; Croff, A.; Baron, P.; Chauvin, N.; Eschbach, R.; Rimpault, G.; Serp, J.; Bergeron, A.; Bromley, B.; Floyd, M.; Hamilton, H.; Hyland, B.; Wojtaszek, D.; McDonald, M.; Collins, E.; Cornet, S.; Michel-Sendis, F.; ); Feinberg, O.; Ignatiev, V.; Hesketh, K.; Kelly, J.F.; Porsch, D.; Vidal, J.; Taiwo, T.; Uhlir, J.; Van Den Durpel, L.; Van Den Eynde, G.; Vitanza, C.; Butler, Gregg; Cornet, Stephanie; Dujardin, Thierry; Greneche, Dominique; Nordborg, Claes; Rimpault, Gerald; Van Den Durpel, Luc; Michel-Sendis, Franco

    2015-01-01

    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)

  11. Determination of traces of thorium in ammonium/sodium diuranate by ICP-AES method

    International Nuclear Information System (INIS)

    Nair, V.R.; Kartha, K.N.M.

    1999-01-01

    Full text: Indian Rare Earths Ltd., Alwaye, produces ammonium diuranate from the thorium concentrate, obtained during monazite processing. This process involves a series of steps. The final uranium product obtained always contains microgram amounts of thorium as impurity. An analytical procedure has been standardised for the estimation of microgram amounts of thorium in ammonium/sodium diuranate. The method involves solvent extraction of uranium by using a tertiary amine followed by the determination of thorium by ICP-AES method in the raffinate. The recoveries of thorium were checked by standard addition to the uranium matrix. Limit of detection is adequate for the analysis of nuclear grade material

  12. Recovery and purification of ethylene

    Science.gov (United States)

    Reyneke, Rian [Katy, TX; Foral, Michael J [Aurora, IL; Lee, Guang-Chung [Houston, TX; Eng, Wayne W. Y. [League City, TX; Sinclair, Iain [Warrington, GB; Lodgson, Jeffery S [Naperville, IL

    2008-10-21

    A process for the recovery and purification of ethylene and optionally propylene from a stream containing lighter and heavier components that employs an ethylene distributor column and a partially thermally coupled distributed distillation system.

  13. 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

  14. Uranium hexafluoride purification; Purificacao de hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Eneas F. de

    1986-07-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF{sub 6}-HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF{sub 6}-HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  15. Drinking water purification in the Czech Republic and worldwide

    International Nuclear Information System (INIS)

    Krmela, Jan; Beckova, Vera; Vlcek, Jaroslav; Marhol, Milan

    2012-06-01

    The report is structured as follows: (i) Legislative (hygienic) requirements for technologies applied to drinking water purification with focus on uranium elimination; (ii) Technological drinking water treatment processes (settling, filtration, precipitation, acidification, iron and manganese removal) ; (iii) State Office for Nuclear Safety requirements for the operation of facilities to separate uranium from drinking water and for the handling of saturated ionexes from such facilities; (iv) Material requirements for the operation of ionex filters serving to separate uranium from drinking water; (v) Effect of enhanced uranium concentrations in drinking waters on human body; (vi) Uranium speciation in ground waters; (vii) Brief description of technologies which are used worldwide for uranium removal; (viii) Technologies which are usable and are used in the Czech Republic for drinking water purification from uranium; (ix) Inorganic and organic ion exchangers and sorbents. (P.A.)

  16. Selective Precipitation of Thorium lodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores

    Science.gov (United States)

    Grimaldi, F.S.

    1957-01-01

    This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented by the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 mg. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.

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

    International Nuclear Information System (INIS)

    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)

  18. Short-term storage considerations for spent plutonium-thorium fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Blomeley, L.; Dugal, C.; Masala, E.; Tran, T., E-mail: laura.blomeley@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2015-12-15

    To support the development of advanced pressurized heavy water reactor (PHWR) fuel cycles, it is necessary to study short-term storage solutions for spent reactor fuel. In this paper, some representational criticality safety and shielding assessments are presented for a particular PHWR plutonium-thorium based fuel bundle concept in a hypothetical aboveground dry storage module. The criticality assessment found that the important parameters for the storage design are neutron absorber content and fuel composition, particularly in light of the high sensitivity of code results to plutonium. The shielding assessment showed that the shielding as presented in the paper would need to be redesigned to provide greater gamma attenuation. These findings can be used to aid in designing fuel storage facilities. (author)

  19. Determination of uranium and thorium in rock samples from Harargaj Anticline by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Rahman, M.; Molla, N.I.; Sharif, A.K.M.; Basunia, S.; Islam, S.; Miah, R.U.; Hossain, S.M.; Chowdhury, M.I.; Bhuiyan, A.D.; Stegnar, P.

    1993-01-01

    Uranium and thorium were determined in geological materials such as radioactive rock samples collected from the Harargaj Anticline in Moulavi Bazar. The pure instrumental neutron activation analysis (INAA) technique was used in qualitative and quantitative analysis of the rock samples for U and Th. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of the order of 10 12 n*cm -2 *s -1 using the TRIGA MARK II research reactor facility at the AERE, Savar, Dhaka. After activation the samples were subjected to γ-ray spectrometry using a high purity germanium detection system. As a result of the analysis, U and Th could be determined. The data are consistent with the values reported by the ground radiometric survey group for some of the samples. (author) 7 refs.; 1 fig.; 2 tabs

  20. Thorium utilization program. Quarterly progress report for the period ending May 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-06-01

    Results of work performed under the National HTGR Fuel Recycle Program (also known as the Thorium Utilization Program) at General Atomic Company are presented. Results of work on this program prior to June 1974 were included in a quarterly series on the HTGR Base Program. The work reported includes the development of unit processes and equipment for reprocessing of High-Temperature Gas-Cooled Reactor (HTGR) fuel, the design and development of an integrated pilot line to demonstrate the head end of HTGR reprocessing using unirradiated fuel materials, and design work in support of Hot Engineering Tests (HET). Work is also described on trade-off studies concerning the required design of facilities and equipment for the large-scale recycle of HTGR fuels in order to guide the development activities for HTGR fuel recycle.

  1. Verification of a Subgroup Generation Method for Thorium Fuel Assemblies

    International Nuclear Information System (INIS)

    Sim, Ohsung; Kim, Myunghyun

    2013-01-01

    Resonance parameter consists of subgroup level and weight. The subgroup weight is obtained by solving the ultrafine slowing down equation and fixed source problem. That means this cross section library procedure considers conservation of the shielded cross section for pin-cell in order to obtain subgroup parameters. There are some isotopes to be concerned for research such as actinides and thorium. Minor actinides(MA) are existing with very small amount in a spent fuel, but effect is not negligible in a high burnup fuel assemblies. Some MAs have high fission cross sections under thermal neutron spectrum. Thorium isotopes was not investigated as much as uranium, but it has high potential for future application. In this study, a new cross section library to be replaced with HELIOS library was generated and compared for the assembly calculation, specially for assembly with thorium. An average capture cross section value at a certain fuel pin and multiplication factor of assembly were compared with nTRACER calculation with HELIOS library and Monte Carlo calculation of MCNP with ENDF-B/II. The accuracy of library data generated for thorium isotope in nTRACER calculation was tested for WASB model. There was a great improvement in K-eff and capture cross section for this assembly compared with old library, HELIOS library

  2. Transmutation of minor actinide using thorium fueled BWR core

    International Nuclear Information System (INIS)

    Susilo, Jati

    2002-01-01

    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 6 t h 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

  3. Decontamination of liquid radioactive waste by thorium phosphate

    International Nuclear Information System (INIS)

    Rousselle, J.; Grandjean, S.; Dacheux, N.; Genet, M.

    2004-01-01

    In the field of the complete reexamination of the chemistry of thorium phosphate and of the improvement of the homogeneity of Thorium Phosphate Diphosphate (TPD, Th 4 (PO 4 ) 4 P 2 O 7 ) prepared at high temperature, several crystallized compounds were prepared as initial powdered precursors. Due to the very low solubility products associated to these phases, their use in the field of the efficient decontamination of high-level radioactive liquid waste containing actinides (An) was carefully considered. Two main processes (called 'oxalate' and 'hydrothermal' chemical routes) were developed through a new concept combining the decontamination of liquid waste and the immobilization of the actinides in a ceramic matrix (TPD). In phosphoric media ('hydrothermal route'), the key-precursor was the Thorium Phosphate Hydrogen Phosphate hydrate (Th 2 (PO 4 ) 2 (HPO 4 ). H 2 O, TPHP, solubility product log(K S,0 0 ) ∼ - 67). The replacement of thorium by other tetravalent actinides (U, Np, Pu) in the structure, leading to the preparation of Th 2-x/2 An x/2 (PO 4 ) 2 (HPO 4 ). H 2 O solid solutions, was examined. A second method was also considered in parallel to illustrate this concept using the more well-known precipitation of oxalate as the initial decontamination step. For this method, the final transformation to single phase TPD containing actinides was purchased by heating a mixture of phosphate ions with the oxalate precipitate at high temperature. (authors)

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

    International Nuclear Information System (INIS)

    Safavi, Afsaneh; Sadeghi, Marzieh

    2006-01-01

    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 -6 -2.00 x 10 -4 M with a limit of detection of 6 x 10 -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

  5. Fabrication of thorium nitrate at the factory at the Bouchet

    International Nuclear Information System (INIS)

    Braun, C.; Lorrain, Ch.; Mahut, R.; Mariette, R.; Muller, J.; Prugnard, J.

    1958-01-01

    A urano-thorianite mineral from Madagascar is industrially treated at the factory of the Bouchet in order to obtain pure thorium in the form of the nitrate and a uranium concentrate in the form of uranate. The required factory was designed and constructed in 1955 and 1956 by the firm Potasse et Engrais Chimiques (P.E.C.) on behalf of the French Atomic Energy authority. The mineral which has previously undergone a gravimetric sorting and enrichment at the mine, is in the form of a heavy rock (the density can be as high as 10), having a cubic structure. It consists principally of a mixture of thorium oxide and uranium oxide and contains between 50 and 75 per cent thorium and between 5 and 20 per cent of uranium. On the same sample a high content in either thorium or uranium in general corresponds to a low content in the other of the two metals; this rule is not however always obeyed absolutely. Among other elements present we shall only mention the Pb, Fe, Ce, Ra and other radioactive elements, since their presence influences the treatment of the mineral. We shall first briefly describe the process, which has already been described in previous publications, we consider to be worthy of attention. (author) [fr

  6. Use of thorium for high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Guimarães, Cláudio Q., E-mail: claudio_guimaraes@usp.br [Universidade de São Paulo (USP), SP (Brazil). Instituto de Física; Stefani, Giovanni L. de, E-mail: giovanni.stefani@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Santos, Thiago A. dos, E-mail: thiago.santos@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo André, SP (Brazil)

    2017-07-01

    The HTGR ( High Temperature Gas-cooled Reactor) is a 4{sup th} generation nuclear reactor and is fuelled by a mixture of graphite and fuel-bearing microspheres. There are two competitive designs of this reactor type: The German “pebble bed” mode, which is a system that uses spherical fuel elements, containing a graphite-and-fuel mixture coated in a graphite shell; and the American version, whose fuel is loaded into precisely located graphite hexagonal prisms that interlock to create the core of the vessel. In both variants, the coolant consists of helium pressurised. The HTGR system operates most efficiently with the thorium fuel cycle, however, so relatively little development has been carried out in this country on that cycle for HTGRs. In the Nuclear Engineering Centre of IPEN (Instituto de Pesquisas Energéticas e Nucleares), a study group is being formed linked to thorium reactors, whose proposal is to investigate reactors using thorium for {sup 233}U production and rejects burning. The present work intends to show the use of thorium in HTGRs, their advantages and disadvantages and its feasibility. (author)

  7. Where are uranium and thorium stored in the Archean basement

    Energy Technology Data Exchange (ETDEWEB)

    Schwinner, R

    1949-01-01

    The author advances a theory which makes it possible to predict where prospecting for new deposits of uranium and thorium should prove successful. According to this theory, such deposits occur chiefly where the equatorial and the meridional branches of the oldest primitive rock systems cross one another. An outline of the earth's Archean basement is included.

  8. 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

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

    International Nuclear Information System (INIS)

    Souza Santos, M.D. de; Goldemberg, J.; Lopes, J.L.

    1985-01-01

    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.) [pt

  10. The thorium fuel cycle in water-moderated reactor systems

    International Nuclear Information System (INIS)

    Critoph, E.

    1977-05-01

    Thorium and uranium cycles are compared with regard to reactor characteristics and technology, fuel-cycle technology, economic parameters, fuel-cycle costs, and system characteristics. In heavy-water reactors (HWRs) thorium cycles having uranium requirements at equilibrium ranging from zero to a quarter of those for the natural-uranium once-through cycle appear feasible. An 'inventory' of uranium of between 1 and 2 Mg/MW(e) is required for the transition to equilibrium. The cycles with the lowest uranium requirements compete with the others only at high uranium prices. Using thorium in light-water reactors, uranium requirements can be reduced by a factor of between two and three from the once-through uranium cycle. The light-water breeder reactor, promising zero uranium requirements at equilibrium, is being developed. Larger uranium inventories are required than for the HWRs. The lead time, from a decision to use thorium to significant impact on uranium utilization (compared to uranium cycle, recycling plutonium) is some two decades

  11. Electronic structure and optical properties of thorium monopnictides

    Indian Academy of Sciences (India)

    Unknown

    Indian Academy of Sciences. 165. Electronic structure and optical properties of thorium monopnictides. S KUMAR* and S AULUCK†. Physics Department, Institute of Engineering and Technology, M.J.P. Rohilkhand University, Bareilly 243 006,. India. †Department of Physics, Indian Institute of Technology, Roorkee 247 667, ...

  12. Comparative Study of Uranium and Thorium Content of Some ...

    African Journals Online (AJOL)

    ... of INAA on related cereals. Quality control and Quality Assurance of the method was tested by analyzing an analytical quality control service (AQCS) reference material (lichen) from International Atomic Energy Agency (IAEA). Keywords: Key words: Uranium, Thorium, neutron activation analysis, Cereals, Katsina, Maradi.

  13. Relativistic Hartree-Bogoliubov description of thorium and uranium isotopes

    International Nuclear Information System (INIS)

    Naz, Tabassum; Ahmad, Shakeb

    2016-01-01

    The relativistic Hartree-Bogoliubov (RHB) theory is a relativistic extension of the Hartree-Fock- Bogoliubov theory. It is a unified description of mean-field and pairing correlations and successfully describe the various phenomenon of nuclear structure. In the present work, RHB is applied to study the thorium and uranium isotopes

  14. Alpha spectrometry and the secondary ion mass spectrometry of thorium

    International Nuclear Information System (INIS)

    Strisovska, J.; Kuruc, J.; Galanda, D.; Matel, L.; Aranyosiova, M.; Velic, D.

    2009-01-01

    The main objective of this master thesis was preparation of samples with thorium content on the steel discs by electrodeposition for determination of natural thorium isotope by alpha spectrometry and the secondary ion mass spectrometry and finding out their possible linear correlation between these methods. The samples with electrolytically excluded isotope of 232 Th were prepared by electrodeposition from solution Th(NO 3 ) 4 ·12 H2 O on steel discs in electrodeposition cell with use of solutions Na 2 SO 4 , NaHSO 4 , KOH and (NH 4 ) 2 (C 2 O 4 ) by electric current 0.75 A. Discs were measured by alpha spectrometer. Activity was calculated from the registered impulses for 232 Th and surface's weight. After alpha spectrometry measurements discs were analyzed by TOF-SIMS IV which is installed in the International Laser Centre in Bratislava. Intensities of isotope of 232 Th and ions of ThO + , ThOH + , ThO 2 H + , Th 2 O 4 H + , ThO 2 - , ThO 3 H - , ThH 3 O 3 - and ThN 2 O 5 H - were identified. The linear correlation is between surface's weights of Th and intensities of ions of Th + from SIMS, however the correlation coefficient has relatively low value. We found out with SIMS method that oxidized and hydride forms of thorium are significantly represented in samples with electroplated thorium. (authors)

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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)

  16. Pollution of agricultural crops with lanthanides, thorium and uranium studied

    Czech Academy of Sciences Publication Activity Database

    Kučera, Jan; Mizera, Jiří; Řanda, Zdeněk; Vávrová, M.

    2007-01-01

    Roč. 271, č. 3 (2007), s. 581-587 ISSN 0236-5731 Institutional research plan: CEZ:AV0Z10480505 Keywords : thorium, uranium * agricultural crops * neutron activation analysis Subject RIV: BE - Theoretical Physics Impact factor: 0.499, year: 2007

  17. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Thoron and associated risks in the handling of thorium compounds; Le thoron et les risques associes dans la manipulation des composes du thorium

    Energy Technology Data Exchange (ETDEWEB)

    Pradel, J; Billard, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    1. Thorium compounds continually give off thoron and its daughters and their radioactivity can constitute a danger for operators who may inhale them. 2. By analogy with radon the maximum admissible content in air of thoron and its daughters has been set at 10{sup -7} {mu}c/cm{sup 3}. However the differences in behaviour between radon and its active deposit on the one hand, and thoron and its daughters on the other, appear great enough to justify more thorough investigation. In fact it seemed probable that, contrary to what takes place with radon, the thoron + thorium A content at a given point may differ appreciable from the thorium B + thorium C + thorium C' + thorium C'' content at the same point, because of the considerable differences in half-life which allow a greater or lesser distribution. 3. To determine the relative concentrations it was necessary to develop a method for estimating thoron in equilibrium with thorium A, the measurement of thorium B and its daughters being carried out in the conventional way by counting the activity collected on a filter. 4. Another object of this study was to estimate the danger presented by thoron in equilibrium with thorium A in the immediate vicinity of thorium sources, in a plant extracting thorium from urano-thorianite. (author) [French] 1. Le thoron et ses descendants se degagent constamment des composes du thorium et leur radioactivite peut presenter un danger pour les personnes qui sont amenees a les respirer. 2. Par analogie avec le radon, la teneur maximum admissible dans l'air de thoron et de ses descendants a ete fixee a 10{sup -7} {mu}c/cm{sup 3}. Mais, les differences de comportement du radon et de son depot actif d'une part, du thoron et de ses descendants d'autre part, ont paru suffisantes pour justifier une etude plus complete. Il semblait en effet probable, contrairement a ce qui se produit pour le radon, qu'en un meme point, la teneur en thoron + thorium A puisse differer notablement de la teneur en

  1. Thoron and associated risks in the handling of thorium compounds; Le thoron et les risques associes dans la manipulation des composes du thorium

    Energy Technology Data Exchange (ETDEWEB)

    Pradel, J.; Billard, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    1. Thorium compounds continually give off thoron and its daughters and their radioactivity can constitute a danger for operators who may inhale them. 2. By analogy with radon the maximum admissible content in air of thoron and its daughters has been set at 10{sup -7} {mu}c/cm{sup 3}. However the differences in behaviour between radon and its active deposit on the one hand, and thoron and its daughters on the other, appear great enough to justify more thorough investigation. In fact it seemed probable that, contrary to what takes place with radon, the thoron + thorium A content at a given point may differ appreciable from the thorium B + thorium C + thorium C' + thorium C'' content at the same point, because of the considerable differences in half-life which allow a greater or lesser distribution. 3. To determine the relative concentrations it was necessary to develop a method for estimating thoron in equilibrium with thorium A, the measurement of thorium B and its daughters being carried out in the conventional way by counting the activity collected on a filter. 4. Another object of this study was to estimate the danger presented by thoron in equilibrium with thorium A in the immediate vicinity of thorium sources, in a plant extracting thorium from urano-thorianite. (author) [French] 1. Le thoron et ses descendants se degagent constamment des composes du thorium et leur radioactivite peut presenter un danger pour les personnes qui sont amenees a les respirer. 2. Par analogie avec le radon, la teneur maximum admissible dans l'air de thoron et de ses descendants a ete fixee a 10{sup -7} {mu}c/cm{sup 3}. Mais, les differences de comportement du radon et de son depot actif d'une part, du thoron et de ses descendants d'autre part, ont paru suffisantes pour justifier une etude plus complete. Il semblait en effet probable, contrairement a ce qui se produit pour le radon, qu'en un meme point, la teneur en thoron + thorium A puisse

  2. A comparative study between the dissolution and the leaching methods for the separation of rare earths, uranium and thorium from hydrous metal oxide cake obtained by the alkaline digestion of monazite

    International Nuclear Information System (INIS)

    Chayavadhanangkur, C.; Busamongkol, A.; Hongsirinirachorn, S.; Rodthongkom, C.; Sirisena, K.

    1986-12-01

    Methods for the group-separation of rare-earths, thorium and uranium from hydrous metal oxide cake obtained by the alkaline digestion of monazite were studied. Leaching of the hydrous metal oxide cake at pH between 4-5 separates the elements under investigation into 3 major groups which are suitable to be used as feed materials for further purification. Total dissolution and gradient precipitation at pH 4-5 yields a poorer separation in comparison to the leaching method

  3. 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)

    Pszonicki, L.; Hanna, A.N.; Suschny, O.

    1983-06-01

    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

  4. Water Purification Systems

    Science.gov (United States)

    1994-01-01

    Clearwater Pool Technologies employs NASA-developed silver/copper ionization to purify turtle and dolphin tanks, cooling towers, spas, water recycling systems, etc. The pool purifier consists of a microcomputer to monitor water conditions, a pair of metallic electrodes, and a rheostat controller. Ions are generated by passing a low voltage current through the electrodes; the silver ions kill the bacteria, and the copper ions kill algae. This technology has found broad application because it offers an alternative to chemical disinfectants. It was originally developed to purify water on Apollo spacecraft. Caribbean Clear has been using NASA's silver ionization technology for water purification for more than a decade. Two new products incorporate advancements of the basic technology. One is the AquaKing, a system designed for areas with no source of acceptable drinking water. Another is the Caribbean Clear Controller, designed for commercial pool and water park applications where sanitizing is combined with feedback control of pH and an oxidizer, chlorine or bromine. The technology was originally developed to purify water on Apollo spacecraft.

  5. Liquid metal purification device

    International Nuclear Information System (INIS)

    Sakai, Takao; Shimoyashiki, Shigehiro.

    1992-01-01

    The device of the present invention concerns a liquid metal purification device for removing and purifying impuries in liquid metal sodium used as coolants of an FBR type reactor. A vessel having a group of pipes made of hydrogen permeable metal at the inside thereof is disposed to the inlet pipeline of a cold trap. The group of hydrogen permeable metal pipes is connected to an exhaust pipe and a vacuum pump, so that the inside of the pipes is exhausted. Liquid metal sodium branched from the main pipeline of a coolant system passes through the outer side of the group of the hydrogen permeable metal pipes. In this cae, hydrogen contained as impurities in the liquid metal sodium diffuses and permeates the hydrogen permeation metal pipes and enters into the pipe group and is discharged out of the system by the vacuum pump. This can mitigate the hydrogen removing burden of the cold trap, to extend the device life time. (I.N.)

  6. Thematic network on the analysis of thorium and its isotopes in workplace materials. Report on the 2nd intercomparison exercise

    International Nuclear Information System (INIS)

    Howe, A.; White, M.

    2000-12-01

    Work Package 2 (WP 2) of the EC Thematic Network on ''The analysis of thorium and its isotopes in workplace materials'' is concerned with ''Examination and comparison of analytical techniques for the determination of thorium and its progeny in bulk materials and the development of standards, both for the calibration of associated metrological facilities, and for routine quality control purposes''. The primary objective of WP 2 is ''To evaluate appropriate techniques and determine best practice for analysis of 232 Th at workplace levels and environments'', and is to be achieved through a series of intercomparison exercises. Following the results of the 1st intercomparison exercise, a 2nd intercomparison exercise was designed to evaluate the capability of the analytical methods currently being used by European laboratories to determine thorium at very low levels in the presence of a complex inorganic matrix. The intercomparison exercise involved the analysis of three samples of thorium in solution, prepared by the United Kingdom National Physical Laboratory. One sample was the equilibrium solution, analysed in the 1st intercomparison exercise. The other two samples were prepared by dilution of a non-equilibrium thorium solution, one of which was spiked with impurity elements. (i) The results showed a further improvement in the accuracy of measurements in the equilibrium solution, when compared with the results from the 1st intercomparison study. There was an overall drop in u-test values and the number of u-test values above the upper limit of significance fell from 6 to 3. (ii) Overall, participating laboratories also performed well in the analysis of the low level non-equilibrium solutions. However, several laboratories using y-spectrometry had insufficient sensitivity for measurement of low level non-equilibrium sample solutions and did not report results. (iii) There was little evidence that the presence of impurities had a detrimental effect on measurements made

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

    International Nuclear Information System (INIS)

    Guo Pengran; Jia Xiaoyu; Duan Taicheng; Xu Jingwei; Chen Hangting

    2010-01-01

    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 2 , NH 4 NO 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 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.

  8. 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.

  9. Rapid purification of recombinant histones.

    Science.gov (United States)

    Klinker, Henrike; Haas, Caroline; Harrer, Nadine; Becker, Peter B; Mueller-Planitz, Felix

    2014-01-01

    The development of methods to assemble nucleosomes from recombinant histones decades ago has transformed chromatin research. Nevertheless, nucleosome reconstitution remains time consuming to this day, not least because the four individual histones must be purified first. Here, we present a streamlined purification protocol of recombinant histones from bacteria. We termed this method "rapid histone purification" (RHP) as it circumvents isolation of inclusion bodies and thereby cuts out the most time-consuming step of traditional purification protocols. Instead of inclusion body isolation, whole cell extracts are prepared under strongly denaturing conditions that directly solubilize inclusion bodies. By ion exchange chromatography, the histones are purified from the extracts. The protocol has been successfully applied to all four canonical Drosophila and human histones. RHP histones and histones that were purified from isolated inclusion bodies had similar purities. The different purification strategies also did not impact the quality of octamers reconstituted from these histones. We expect that the RHP protocol can be readily applied to the purification of canonical histones from other species as well as the numerous histone variants.

  10. RELIGION AND PURIFICATION OF SOUL

    Directory of Open Access Journals (Sweden)

    Azam Khodashenas Pelko

    2010-11-01

    Full Text Available The Jainism emphasizes three major teachings about the purification of the soul (jiva, Ahimsa, Aparigrapha and anekantwad. Jainism, The focus of this religion has been purification of the soul by means of right conduct, right faith and right knowledge. The ultimate goal of Hinduism is Moksha or liberation (total freedom. In Hinduism, purification of the soul is a goal that one must work to attain. The Buddhism is the science of pursuing the aim of making the human mind perfect, and of purifying the human soul. The knowledge of purifying of the soul and softening of the hearts is as essential for human. They having the correct motivations means purifying our souls from hypocrisy, caprice, and heedlessness. The primary goal of Taoism may be described as the mystical intuition of the Tao, which is the way, the undivided unity, and the ultimate Reality. According to the Christianity access to truth cannot be conceived without purity of the soul

  11. Antimicrobial Peptide Production and Purification.

    Science.gov (United States)

    Suda, Srinivas; Field, Des; Barron, Niall

    2017-01-01

    Antimicrobial peptides (AMPs) are natural defense compounds which are synthesized as ribosomal gene-encoded pre-peptides and produced by all living organisms. AMPs are small peptides, usually cationic and typically have hydrophobic residues which interact with cell membranes and have either a narrow or broad spectrum of biological activity. AMPs are isolated from the natural host or heterologously expressed in other hosts such as Escherichia coli. The proto-typical lantibiotic Nisin is a widely used AMP that is produced by the food-grade organism Lactococcus lactis. Although AMP production and purification procedures require optimization for individual AMPs, the Nisin production and purification protocol outlined in this chapter can be easily applied with minor modifications for the production and purification of other lantibiotics or AMPs. While Nisin is produced and secreted into the supernatant, steps to recover Nisin from both cell-free supernatant and cell pellet are outlined in detail.

  12. Partial Purification and Characterization of Extracellular Protease ...

    African Journals Online (AJOL)

    Nigerian Journal of Basic and Applied Sciences ... Purification of the enzyme by gel filtration chromatography on Sephadex G75 following ammonium sulphate precipitation gave 2.26 fold increase in purification with specific activity of 46.13 units/mg protein while purification on Sephadex CM50 resulted in reduced ...

  13. Purification of Water by Aquatic Plants

    OpenAIRE

    Morimitsu, Katsuhito; Kawahigashi, Tatsuo

    2013-01-01

    [Abstract] Water quality purification of many water systems including those occurring in rivers depends to a great degree on water quality purification activities of aquatic plants and microbes. This paper presents a discussion of results, based on laboratory experiments, of purification by aquatic plants.

  14. Materials for Molybdenum 99 purification

    International Nuclear Information System (INIS)

    Wilkinson, M. Victoria; Mondino, Angel V.; Manzini, Alberto C.

    2003-01-01

    The National Atomic Energy Commission (CNEA) produces fission Mo 99, an isotope of wide use in nuclear medicine. In order to simplify the current Mo 99 production process, to shorten its duration and reduce impurities in the final product, alternative methods for purification steps were looked for. In this work a variety of new materials for the purification columns were designed, all of them with carbon. These materials were studied and a material which contribute with the best results for molybdenum retention, was selected. The preparation procedure and the working conditions were determined. (author)

  15. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  16. Determination of uranium, thorium and radium isotope ratio

    International Nuclear Information System (INIS)

    Sokolova, Z.A.

    1983-01-01

    The problems connected with the study of isotope composition of natural radioactive elements in natural objects are considered. It is pointed out that for minerals, ores and rocks the following ratios are usually determined: 234 U/ 238 U, 230 Th/ 238 U, 226 Ra/ 238 U, 228 Th/ 230 Th, 228 Th/ 232 Th and lead isotopes; for natural waters, besides the enumerated - 226 Ra/ 228 Ra. General content of uranium and thorium in the course of isotope investigations is determined from separate samples, most frequently by the X-ray spectral method, radium content - by usual radiochemical method, uranium and radium content in waters -respectively by calorimetric and emanation methods. Radiochemical preparation of geologic powder and aqueous samples for isotope analysis is described in detail. The technique of measuring and calculating isotope ratios (α-spectrometry for determining isotope composition of uranium and thorium and emanation method for determining 226 Ra/ 228 Ra) is presented

  17. Origin of blue emission in thorium oxide nanorods

    International Nuclear Information System (INIS)

    Gupta, Santosh K.; Natarajan, V.; Ghosh, P.S.; Arya, A.

    2014-01-01

    Thorium oxide, ThO 2 , has long been an important material in the nuclear industry and has more recently found utility in the design of a variety of new materials, including catalysts, electrodes, fuel cell, electrolytes and sensors. Thorium dioxide is an interesting host matrix for a variety of reasons like its low phonon energy (∼450 cm -1 ), which reduces the non-radiative losses. Among all the chemical processes, the micro emulsion processing (reverse micelles synthesis) has been demonstrated as a very versatile and reproducible method. Luminescence of pure metal oxides is usually assigned to crystal lattice defects formed by oxygen vacancies but the obvious experimental evidences for this assumption are absent. Optical properties of stoichiometric and oxygen-deficient thoria have never been investigated previously

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

    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 Científicas y Técnicas (Argentina); Llois, A.M. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Científicas 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)

    2016-11-15

    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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  1. 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.

  2. The hydrolysis of thorium dicarbide and of mixed uranium-thorium dicarbides; L'hydrolyse du dicarbure de thorium et des dicarbures mixtes d'uranium et de thorium

    Energy Technology Data Exchange (ETDEWEB)

    Del Litto, B [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1966-09-01

    The hydrolysis of thorium dicarbide leads to the formation of a complex mixture of gaseous and condensed carbon hydrides. The temperature, between 25 and 100 deg. C, has no influence on the nature and composition of the gas phase. The reaction kinetics, however, are strongly temperature dependent. In a hydrochloric medium, an enrichment in hydrogen of the gas mixture is observed. On the other hand a decrease in hydrogen and an increase in acetylene content take place in an oxidizing medium. The general results can be satisfactorily interpreted through a reaction mechanism involving C-C radical groups. In the same way, the hydrolysis of uranium-thorium-carbon ternary alloys leads to the formation of gaseous and condensed carbon hydrides. The variation of the composition of the gas phase versus uranium content in the alloy suggests an hypothesis about the carbon-carbon distance in the alloy crystal lattice. The variation of methane content, on the other hand, has lead us to discuss the nature of the various phases present in uranium-carbon alloys and carbon-rich uranium-thorium-carbon alloys. We have reached the conclusion that these alloys include a proportion of monocarbide which is dependent upon the ratio. Th/(Th + U). We put forward a diagram of the system uranium-carbon with features proper to explain some phenomena which have been observed in the uranium-thorium-carbon ternary diagram. (author) [French] L'hydrolyse du dicarbure de thorium conduit a la formation d'un melange complexe d'hydrures de carbone gazeux et condenses. La temperature entre 25 et 100 deg. C n'a pas d'influence sur la nature ef la composition de la phase gazeuse. Par contre la cinetique en depend fortement. En milieu chlorhydrique, on observe un enrichissement en hydrogene du melange gazeux. Au contraire, en milieu oxydant il se produit une diminution du taux d'hydrogene et une augmentation tres nette du taux d'acetylene. L'ensemble des resultats obtenus peut etre interprete d'une maniere

  3. Study on thorium removal from effluent by electrocoagulation

    International Nuclear Information System (INIS)

    Nath, Baidurjya; Swaroopa Lakshmi, Y.V.; Tiwari, S.K.; Setty, D.S.; Kalyanakrishnan, G.; Saibaba, N.

    2015-01-01

    Coagulation-flocculation, membrane separation and ion-exchange are traditional methods for treatment of radioactive wastewater generated primarily from the front end processes of the fuel cycle. Electrocoagulation presents a robust and novel alternative to conventional coagulation process. The present study involves the establishment of electrocoagulation as a treatment process for thorium bearing non-process effluents in batch mode. This involved an electrolytic reactor with iron electrodes. The non-process effluent was subjected to coagulation and floatation by Fe(II) ions dissolved from the anode with the resultant flocs floating on the surface after being captured by hydrogen gas bubbles generated at the cathode. The effect of various operational parameters like initial pH, residence time, current density and initial thorium concentration on the removal efficiency was investigated. Maximum decontamination factor obtained was of the order of 10 4 . (author)

  4. Economics of uranium and thorium for the generation of electricity

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1958-09-15

    Only a few years ago there was serious talk of the prospect that economically available supplies of uranium and thorium might restrict the development of nuclear power. Now the position is reversed and the state of technical development of nuclear power threatens to restrict the market for the abundant supply of these minerals. Uranium and thorium are essentially fuels well suited to the generation of large blocks of electricity. As such, they must be assessed in relation to competitive fuels -- coal, oil and natural gas and the other large sources, namely water power. The most relevant basis is therefore a study of the demand for electric power and the costs of available sources where this demand exists. (author)

  5. Coordination compounds of titanium, zirconium, tin, thorium and uranium

    International Nuclear Information System (INIS)

    Deshpande, S.G.; Jain, S.C.

    1990-01-01

    Reactions of isatin, furoic acid and picolinic acid have been carried out with titanium tetrachloride, tin tetrachloride, thorium tetrachloride, zirconyl chloride and uranyl nitrate. While 2:3(metal:ligand) type compounds of isatin have been obtained with Ti(IV) and Sn(IV), zirconium(IV), thorium(IV), and uranium(VI) do not react with the ligand under similar experimental conditions. Furoic acid (FAH) and picolinic acid(PicH) form various chloro furoates and picolinates when reacted with TiCl 4 , ZrOCl 2 and ThCl 4 , but do not react with SnCl 4 . The various compounds synthesised have been characterised on the basis of elemental analysis, infrared studies, conductivity and thermogravimetric measurements. (author). 1 tab., 10 refs

  6. Coprecipitation of thorium and uranium peroxides from acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    McTaggart, D.R.; Mailen, J.C.

    1981-01-01

    The factors affecting successful coprecipitation of thorium and uranium peroxides from acid media were studied. Variables considered in this work were H/sup +/ concentration, H/sub 2/O/sub 2/ concentration, duration of contact, and rate of feed solution addition. In all experiments, stock solutions of Th(NO/sub 3/)/sub 4/ and UO/sub 2/(NO/sub 3/)/sub 2/ were fed at a controlled rate into H/sub 2/O/sub 2/ solutions with constant stirring. Samples were taken as a function of time to follow the H/sup +/ concentration of the solution, uranium precipitation, thorium precipitation, precipitant weight/volume of solution, and crystalline structure and growth. The optimum conditions for maximum coprecipitation are low H/sup +/ concentration, high H/sub 2/O/sub 2/ concentration, and extended contact time between the solutions.

  7. Road-map design for thorium-uranium breeding recycle in PWR - 031

    International Nuclear Information System (INIS)

    Shengyi, Si

    2010-01-01

    The paper was focused on designing a road-map to finally approach sustainable Thorium-Uranium ( 232 Th- 233 U) Breeding Recycle in current PWR, without any other change to the fuel lattice and the core internals, but substituting the UOX pellet with Thorium-based pellet. At first, the paper presented some insights to the inherence of Thorium-Uranium fuel conversion or breeding in PWR based on the neutronics theory and revealed the prerequisites for Thorium-Uranium fuel in PWR to achieve sustainable Breeding Recycle; And then, various Thorium-based fuels were designed and examined, and the calculation results further validated the above theoretical deductions; Based on the above theoretical analysis and calculation results, a road-map for sustainable Thorium-Uranium breeding recycle in PWR was outlined finally. (authors)

  8. Separation of protactinum, actinium, and other radionuclides from proton irradiated thorium target

    Science.gov (United States)

    Fassbender, Michael E.; Radchenko, Valery

    2018-04-24

    Protactinium, actinium, radium, radiolanthanides and other radionuclide fission products were separated and recovered from a proton-irradiated thorium target. The target was dissolved in concentrated HCl, which formed anionic complexes of protactinium but not with thorium, actinium, radium, or radiolanthanides. Protactinium was separated from soluble thorium by loading a concentrated HCl solution of the target onto a column of strongly basic anion exchanger resin and eluting with concentrated HCl. Actinium, radium and radiolanthanides elute with thorium. The protactinium that is retained on the column, along with other radionuclides, is eluted may subsequently treated to remove radionuclide impurities to afford a fraction of substantially pure protactinium. The eluate with the soluble thorium, actinium, radium and radiolanthanides may be subjected to treatment with citric acid to form anionic thorium, loaded onto a cationic exchanger resin, and eluted. Actinium, radium and radiolanthanides that are retained can be subjected to extraction chromatography to separate the actinium from the radium and from the radio lanthanides.

  9. Thorium content of a mineral ore from Morro do Ferro by fission track technique

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de.

    1980-10-01

    The feasibility to determine thorium concentrations by fission track technique in samples of mineral ore has been demonstrated. The literature registers only the application of the fission track technique to mineral ore in the case where the fissionable element is uranium. The technique was applied to determine the thorium concentration of an ore sample from Morro do Ferro, taking advantage of the high thorium to uranium ratio in that mineral. The sample analysed presented a thorium concentration of 2467 +- 400 mg Th/Kg ore. The so called wet method was adopted by using the Bayer made Makrofol KG 10μm thick, as the detector foil, immersed in the thorium solution. The technique is also useful to determine thorium concentrations in environmental samples because of the following aspects: high sensitivity; fast chemical separation of interfering elements; low cost; and operational simplicity. (Author) [pt

  10. Activities of the research committee on thorium cycle in atomic energy society of Japan

    International Nuclear Information System (INIS)

    Hohki, Shiro

    1985-01-01

    In 1978 the Research Committee on Thorium Cycle was established as one of committees of the Atomic Energy Society of Japan, and the Committee published a report titled 'The Thorium Cycle - Present Status and Future Prospect' in October 1980 as a result of investigations on the status of the thoirum cycle in Japan as well as that in overseas. Based on this investigation, the Committee is intending to evaluate synthetically the thorium utilization in Japan under the prospect for the middle and long term by intensifying the activities of the Committee. Furthermore, from this viewpoint, the author supplements comments on following three points: (1) Reasons why the thorium utilization has not received positive evaluation in Japan; (2) Reasons why Japan has to pay attention to thorium; (3) How the technology on thorium should be developed in Japan. (author)

  11. A simple access to pure thorium(IV) halides (ThCl{sub 4}, ThBr{sub 4}, and ThI{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Deubner, H. Lars; Rudel, Stefan Sebastian; Kraus, Florian [Fachbereich Chemie, Philipps-Universitaet Marburg (Germany)

    2017-12-13

    In this work we present a facile, lab scale synthesis for thorium tetrahalides ThX{sub 4} (X = Cl, Br, and I). The reaction between the easily available ThO{sub 2} and AlX{sub 3} (X = Cl, Br, and I) and a subsequent in situ chemical vapor transport (CVT) leads to a product of high purity, which is obtained in the form of crystals or large aggregates of crystals. Their identity and purity was evidenced by X-ray powder diffraction and IR spectroscopy. The usage of ThO{sub 2} avoids, unlike earlier syntheses, the utilization of scarcely available thorium metal or of other reactants, such as CCl{sub 4}, which leads to impurities. Furthermore, the reaction tolerates even less pure ThO{sub 2}. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. (D,T) Driven thorium hybrid blankets

    International Nuclear Information System (INIS)

    Al-Kusayer, T.A.; Khan, S.; Sahin, S.

    1983-01-01

    Recently, a project has started, with the aim to establish the neutronic performance and the basic design of an experimental fusionfission (hybrid) reactor facility, called AYMAN, in cylinderical geometry. The fusion reactor will have to be simulated by a (D,T) neutron generator. Fissile and fertile fuel will have to surround the neutron generator as a cylinderical blanket to simulate the boundary conditions of the hybrid blanket in a proper way. This geometry is consistent with Tandem Mirror Hybrid Blanket design and with most of the ICF blanket designs. A similar experimental installation will become operational around 1984 at the Swiss Federal Institute of Technology in Lausanne, Switzerland known under the project LOTUS. Due to the limited dimensions of the experimental cavity of the LOTUS-hybrid reactor, the LOTUS blankets have to be designed in plane geometry. Also, the bulky form of the Haefely neutron generator of the LOTUS facility obliges one to design a blanket in the plane geometry. This results in a vacuum left boundary conditions for the LOTUS blanket. The importance of a reflecting left boundary condition on the overall neutronic performance of a hybrid blanket has been analyzed in previous work in detail

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

    Czech Academy of Sciences Publication Activity Database

    Soudek, Petr; Kufner, Daniel; Petrová, Šárka; Mihaljevič, M.; Vaněk, Tomáš

    2013-01-01

    Roč. 92, č. 9 (2013), s. 1090-1098 ISSN 0045-6535 R&D Projects: GA MŠk LH12162; GA MŠk(CZ) LD13029; GA MPO FR-TI3/778 Institutional research plan: CEZ:AV0Z50380511 Keywords : Thorium * Plant uptake * Polyamines Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.499, year: 2013

  14. Proposed plan for critical experiments supporting thorium fuel cycle development

    International Nuclear Information System (INIS)

    Gore, B.F.

    1978-09-01

    A preliminary plan is proposed for critical experiments to provide data needed for the recycle of thorium based nuclear fuels. The sequence of experimentation starts with well moderated solutions followed by highly concentrated low moderated solutions. It then progresses through lattices moderated by water, by water plus soluble poisons, and by fissile solutions, to solutions poisoned by raschig rings and soluble poisons. Final experiments would treat lattices moderated by poisoned fissile solution, and arrays of stored fissile units

  15. Conversion rate for PWR reactors in thorium cycle

    International Nuclear Information System (INIS)

    Angelkorte, G.M.

    1980-01-01

    This work concerns to the determination of the conversion-rate for a PWR reactor with an enrichment of 7.47%, considering a cell, geometrically equal to Angra I, composed by Thorium and U-238 in a 1:1 relation. The study was performed considering neutrons of one and two groups of energy, according to the suggestion from other authors sup(1,2). It was also performed a study about the production and consumption of fissile material. (author)

  16. Thorium utilization: conversion ratio and fuel needs in thermal reactors

    International Nuclear Information System (INIS)

    Oosterkamp, W.J.

    1975-01-01

    As a preparatory study for thorium utilization in thermal reactors a study has been made of the fuel comsumption in existing reactor types. A quantitative description is given of the influence of enrichment, burnup, amount of structural material, choise of coolant and control requirements on the convertion ratio. The enrichment is an important factor and a low fuel comsumption can be achieved by increasing the enrichment

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  18. 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.

  19. Kinetics of dissolution of thorium and uranium doped britholite ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dacheux, N., E-mail: nicolas.dacheux@univ-montp2.f [Groupe de Radiochimie, Institut de Physique Nucleaire d' Orsay, Bat. 100, Universite Paris-Sud-11, 91406 Orsay (France); Institut de Chimie Separative de Marcoule, UMR 5257 (Universite Montpellier 2/CNRS/CEA/ENSCM), Bat. 426, Centre de Marcoule, BP 17171, 30207 Bagnols sur ceze cedex (France); Du Fou de Kerdaniel, E. [Groupe de Radiochimie, Institut de Physique Nucleaire d' Orsay, Bat. 100, Universite Paris-Sud-11, 91406 Orsay (France); Clavier, N. [Groupe de Radiochimie, Institut de Physique Nucleaire d' Orsay, Bat. 100, Universite Paris-Sud-11, 91406 Orsay (France); Institut de Chimie Separative de Marcoule, UMR 5257 (Universite Montpellier 2/CNRS/CEA/ENSCM), Bat. 426, Centre de Marcoule, BP 17171, 30207 Bagnols sur ceze cedex (France); Podor, R. [Institut de Chimie Separative de Marcoule, UMR 5257 (Universite Montpellier 2/CNRS/CEA/ENSCM), Bat. 426, Centre de Marcoule, BP 17171, 30207 Bagnols sur ceze cedex (France); Institut Jean Lamour - Departement CP2S - Equipe 206, Faculte des Sciences et Techniques - Nancy Universite, BP 70239, 54506 Vandoeuvre les Nancy cedex (France); Aupiais, J. [CEA DAM DIF, 91297 Arpajon (France); Szenknect, S. [Institut de Chimie Separative de Marcoule, UMR 5257 (Universite Montpellier 2/CNRS/CEA/ENSCM), Bat. 426, Centre de Marcoule, BP 17171, 30207 Bagnols sur ceze cedex (France)

    2010-09-01

    In the field of immobilization of actinides in phosphate-based ceramics, several thorium and uranium doped britholite samples were submitted to leaching tests. The normalized dissolution rates determined for several pH values, temperatures and acidic media from the calcium release range from 4.7 x 10{sup -2} g m{sup -2} d{sup -1} to 21.6 g m{sup -2} d{sup -1}. Their comparison with that determined for phosphorus, thorium and uranium revealed that the dissolution is clearly incongruent for all the conditions examined. Whatever the leaching solution considered, calcium and phosphorus elements were always released with higher R{sub L} values than the other elements (Nd, Th, U). Simultaneously, thorium was found to quickly precipitate as alteration product, leading to diffusion phenomena for uranium. For all the media considered, the uranium release is higher than that of thorium, probably due to its oxidation from tetravalent oxidation state to uranyl. Moreover, the evaluation of the partial order related to proton concentration and the apparent energy of activation suggest that the reaction of dissolution is probably controlled by surface chemical reactions occurring at the solid/liquid interface. Finally, comparative leaching tests performed in sulphuric acid solutions revealed a significant influence of such media on the chemical durability of the leached pellets, leading to higher normalized dissolution rates for all the elements considered. On the basis of the results of chemical speciation, this difference was mainly explained in the light of higher complexion constants by sulfate ions compared to nitrate, chloride and phosphate.

  20. Spectrophotometric determination of thorium using arsenazo III in water

    International Nuclear Information System (INIS)

    Rio, M.A.P. do; Godoy, J.M. de.

    1985-01-01

    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) [pt

  1. Optimization of precipitation conditions of thorium oxalate precipitate

    International Nuclear Information System (INIS)

    Pazukhin, Eh.M.; Smirnova, E.A.; Krivokhatskij, A.S.; Pazukhina, Yu.L.; Kiselev, P.P.

    1986-01-01

    Thorium precipitation in the form of difficultly soluble oxalate has been investigated. The equation binding the concentration of metal with the nitric acid in the initial solution and quantity of a precipitator necessary for minimization of desired product losses is derived. The graphical solution of this equation for a case, when the oxalic acid with 0.78 mol/l concentration is the precipitator, is presented

  2. Uranium production in thorium/denatured uranium fueled PWRs

    International Nuclear Information System (INIS)

    Arthur, W.B.

    1977-01-01

    Uranium-232 buildup in a thorium/denatured uranium fueled pressurized water reactor, PWR(Th), was studied using a modified version of the spectrum-dependent zero dimensional depletion code, LEOPARD. The generic Combustion Engineering System 80 reactor design was selected as the reactor model for the calculations. Reactors fueled with either enriched natural uranium and self-generated recycled uranium or uranium from a thorium breeder and self-generated recycled uranium were considered. For enriched natural uranium, concentrations of 232 U varied from about 135 ppM ( 232 U/U weight basis) in the zeroth generation to about 260 ppM ( 232 U/U weight basis) at the end of the fifth generation. For the case in which thorium breeder fuel (with its relatively high 232 U concentration) was used as reactor makeup fuel, concentrations of 232 U varied from 441 ppM ( 232 U/U weight basis) at discharge from the first generation to about 512 ppM ( 232 U/U weight basis) at the end of the fifth generation. Concentrations in freshly fabricated fuel for this later case were 20 to 35% higher than the discharge concentration. These concentrations are low when compared to those of other thorium fueled reactor types (HTGR and MSBR) because of the relatively high 238 U concentration added to the fuel as a denaturant. Excellent agreement was found between calculated and existing experimental values. Nevertheless, caution is urged in the use of these values because experimental results are very limited, and the relevant nuclear data, especially for 231 Pa and 232 U, are not of high quality

  3. Chromosome breakage in peripheral lymphocytes of thorium workers

    International Nuclear Information System (INIS)

    Hoegerman, S.F.; Cummins, H.T.

    1979-01-01

    Cytogenic analysis of 21 thorium workers and 3 controls has not shown a significant elevation in the level of chromosome breakage in the workers' peripheral lymphocytes. The observation of a single dicentric chromosome in 100-cell samples from each of two workers with relatively long periods of occupational exposure and relatively high body burdens suggests, however, that such exposure might result in increases in chromosome aberration frequency

  4. Protactinium-231 found in natural thorium irradiated in JMTR

    International Nuclear Information System (INIS)

    Suzuki, Susumu; Mitsugashira, Toshiaki; Hara, Mitsuo; Satoh, Isamu; Shiokawa, Yoshinobu; Satoh, Michiko

    1987-01-01

    Natural thorium dioxides, which differed in the content of 230 Th, were irradiated in JMTR(Japan Material Testing Reactor). 232 U, 233 U, 231 Pa, 233 Pa, and remaining Th were measured radiometrically. High production of 231 Pa and high consumption of 230 Th were observed and it was necessary to assume large resonance capture of 230 Th in order to explain the production of 231 Pa and the consumption of 230 Th. (author)

  5. Chlorine gas processing of oxide nuclear fuel particles containing thorium

    International Nuclear Information System (INIS)

    Knotik, K.; Bildstein, H.; Falta, G.; Wagner, H.

    Experimental studies on the chloride extraction and separation of U and Th from coated Th--U oxide particles are reported. After a description of the chlorination equipment and the experimental procedures, the results are discussed. The yield of U is determined as a function of the reaction temperature. The results of a thermogravimetric analysis of the chlorination of uranium carbide and thorium carbides are reported and used to establish the reaction mechanism for the chlorination

  6. Global recovery process of thorium and rare earths in a nitrate medium

    International Nuclear Information System (INIS)

    Cailly, F.; Mottot, Y.

    1993-01-01

    The aqueous solution of thorium and rare earth nitrates, obtained by leaching the ore with nitric acid, is extracted by an organic phosphorous compound (phosphate, phosphonate, phosphinate or phosphine oxide) and a cationic extractant chosen among phosphoric acid di-esters. Extraction of thorium and rare earths is possible even in presence of phosphate ions in the aqueous solution. Thorium and rare earths are separated by liquid-liquid extraction of the organic phase

  7. Studies on supercritical fluid extraction behaviour of uranium and thorium nitrates using amides

    International Nuclear Information System (INIS)

    Sujatha, K.; Kumar, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2007-01-01

    Supercritical fluid extraction studies of uranyl nitrate and thorium nitrate in mixture were carried out using various amides such as N,N-di(2-ethylhexyl) isobutyramide (D2EHIBA),N,N-dihexyl octanamide (DHOA) and Diisooctyl Butanamide (DiOBA). These studies established a preferential extraction of uranium over thorium. Among the various amides studied, D2EHIBA offered the best rate of preferential extraction of uranium over thorium. (author)

  8. Thorium and Molten Salt Reactors: Essential Questions for Classroom Discussions

    Science.gov (United States)

    DiLisi, Gregory A.; Hirsch, Allison; Murray, Meredith; Rarick, Richard

    2018-04-01

    A little-known type of nuclear reactor called the "molten salt reactor" (MSR), in which nuclear fuel is dissolved in a liquid carrier salt, was proposed in the 1940s and developed at the Oak Ridge National Laboratory in the 1960s. Recently, the MSR has generated renewed interest as a remedy for the drawbacks associated with conventional uranium-fueled light-water reactors (LWRs) in use today. Particular attention has been given to the "thorium molten salt reactor" (TMSR), an MSR engineered specifically to use thorium as its fuel. The purpose of this article is to encourage the TPT community to incorporate discussions of MSRs and the thorium fuel cycle into courses such as "Physics and Society" or "Frontiers of Physics." With this in mind, we piloted a pedagogical approach with 27 teachers in which we described the underlying physics of the TMSR and posed five essential questions for classroom discussions. We assumed teachers had some preexisting knowledge of nuclear reactions, but such prior knowledge was not necessary for inclusion in the classroom discussions. Overall, our material was perceived as a real-world example of physics, fit into a standards-based curriculum, and filled a need in the teaching community for providing unbiased references of alternative energy technologies.

  9. Fabrication routes for Thorium and Uranium233 based AHWR fuel

    International Nuclear Information System (INIS)

    Danny, K.M.; Saraswat, Anupam; Chakraborty, S.; Somayajulu, P.S.; Kumar, Arun

    2011-01-01

    India's economic growth is on a fast growth track. The growth in population and economy is creating huge demand for energy which has to be met with environmentally benign technologies. Nuclear Energy is best suited to meet this demand without causing undue environmental impact. Considering the large thorium reserves in India, the future nuclear power program will be based on Thorium- Uranium 233 fuel cycle. The major characteristic of thorium as the fuel of future comes from its superior fuel utilization. 233 U produced in a reactor is always contaminated with 232 U. This 232 U undergoes a decay to produce 228 Th and it is followed by decay chain including 212 Bi and 208 Tl. Both 212 Bi and 208 Tl are hard gamma emitters ranging from 0.6 MeV-1.6 MeV and 2.6 MeV respectively, which necessitates its handling in hot cell. The average concentration of 232 U is expected to exceed 1000 ppm after a burn-up of 24,000 MWD/t. Work related to developing the fuel fabrication technology including automation and remotization needed for 233 U based fuels is in progress. Various process for fuel fabrication have been developed i.e. Coated Agglomerate Pelletisation (CAP), impregnation technique (Pellet/Gel), Sol Gel Micro-sphere Pelletisation (SGMP) apart from Powder to Pellet (POP) route. This paper describes each process with respect to its advantages, disadvantages and its amenability to automation and remotisation. (author)

  10. Different periods of uranium and thorium occurrence in Madagascar (1960)

    International Nuclear Information System (INIS)

    Moreau, M.

    1960-01-01

    In Madagascar, the first typical occurrences of thorium and uranium are about 500 million years old. Previously thorium and uranium were rather concentrated in the granitic and charnockitic zones, chiefly in minerals such as monazite, apatite and zircon. At the end of the Precambrian period, metasomatic granites occur especially in the anticlinal series (Andriba orthite granite). The granitization is followed by the formation of the main pegmatitic areas in the Island with Th-U niobotantalates, uraninite and beryl. The pegmatites are well developed in the synclinal series with a poor migmatization or no migmatization at all. In the same time a large uranium and thorium province with uranothorianite deposits appears within the calcomagnesian series of the Southern part of Madagascar. Later, large amounts of monazite were carried down to the detritic Karroo sediments during tile erosion of the metamorphic precambrian rocks. Monazite has been concentrated again by frequent marine incursions, till the present time. In the medium Karroo, near Folakara, uranium minerals occur in direct relation with carbonaceous material. Finally we must note the uranium occurrence in the pleistocene carbonaceous shales of Antsirabe basin, in contact with crystalline rocks. (author) [fr

  11. The future role of thorium in assuring CANDU fuel supplies

    International Nuclear Information System (INIS)

    Slater, J.B.

    1985-01-01

    Atomic Energy of Canada Limited (AECL), in partnership with Canadian industry and power utilities, has developed the CANDU reactor as a safe, reliable and economic means of transforming nuclear fuel into useable power. The use of thorium/uranium-233 recycle gives the possibility of a many-fold increase in energy yield over that which can be obtained from the use of uranium in once-through cycles. The neutronic properties of uranium-233 combine with the inherent neutron economy of the CANDU reactor to offer the possibility of near-breeder cycles in which there is no net consumption of fissile material under equilibrium fuelling conditions. Use of thorium cycles in CANDU will limit the impact of higher uranium prices. When combined with the potential for significant reductions in CANDU capital costs, then the long-term prospect is for generating costs near to current levels. Development of thorium cycles in CANDU will safeguard against possible uranium shortages in the next century, and will maintain and continue the commercial viability of CANDU as a long-term energy technology. (author)

  12. Kinetic study of the thorium phosphate - diphosphate dissolution

    International Nuclear Information System (INIS)

    Dacheux, N.; Thomas, A.C.; Brandel, V.; Genet, M.

    2000-01-01

    The thorium phosphate-diphosphate Th 4 (PO 4 ) 4 P 2 O 7 (TPD) structure allows the replacement of large amounts of thorium by tetravalent actinides leading to the formation of solid solutions. This compound was obtained in powdered or sintered form after pressing at room temperature at 300-800 MPa then heating at 1250 deg. C for 10-30 hours. The resistance of this material to aqueous corrosion was determined by varying several parameters such as surface, leaching flow, acidity or temperature. It was thus possible to independently determine the influence of each parameter on the leaching rate provided that the saturation of the solution was not obtained. In acidic media, the partial order related to [H 3 O + ] was found to be in the 0.31-0.35 range while, in basic media, the partial order related to [OH - ] was almost the same (0.45). The activation energy (42 kJ/mol) was determined between 4 deg. C and 120 deg. C. Moreover, the addition of phosphate in the leachate slightly increased the TPD dissolution rate. When the saturation of the solution is reached, a gelatinous precipitate controls the thorium and phosphate concentrations. The complete characterization of this solid led to the proposed general formula Th 2 (PO 4 ) 2 (HPO 4 ). n H 2 O which conventional solubility product (at I = 0 M) is very low: K * S,0 10 -66.6±1.2 even in very acidic media. (authors)

  13. On the structure of thorium and americium adenosine triphosphate complexes

    International Nuclear Information System (INIS)

    Mostapha, Sarah; Berton, Laurence; Boubals, Nathalie; Zorz, Nicole; Charbonnel, Marie-Christine; Fontaine-Vive, Fabien; Den Auwer, Christophe; Solari, Pier Lorenzo

    2014-01-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electro-spray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes. (authors)

  14. On the structure of thorium and americium adenosine triphosphate complexes.

    Science.gov (United States)

    Mostapha, Sarah; Fontaine-Vive, Fabien; Berthon, Laurence; Boubals, Nathalie; Zorz, Nicole; Solari, Pier Lorenzo; Charbonnel, Marie Christine; Den Auwer, Christophe

    2014-11-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

  15. Alkaline autoclave leaching of refractory uranium-thorium minerals

    International Nuclear Information System (INIS)

    Milani, S. A.; Sam, S.

    2011-01-01

    This paper deals with the study of an innovative method for processing the Oman placer ores by alkaline leaching in ball mill autoclaves, where grinding and leaching of the refractory minerals take place simultaneously. This was followed by the selective separation of thorium and uranium from lanthanides by autoclave leaching of the hydroxide cake with ammonium carbonate-bicarbonate solutions. The introduced method is based on the fact that thorium and uranium form soluble carbonate complexes with ammonium carbonate, while lanthanides form sparingly soluble double carbonates. It was found that a complete alkaline leaching of Oman placer ores (98.0 P ercent ) was attained at 150 and 175 d egree C within 2.5 and 2h, respectively. Oman placer ores leaching was intensified and accelerated in a ball mill autoclaves as a result of the grinding action of steel balls, removal of the hydroxide layer covering ores grains and the continuous contact of fresh ore grains with alkaline solution. The study of selective carbonate processing of hydroxide cake with ammonium carbonate-bicarbonate solutions on autoclave under pressure revealed that the complete thorium recovery (97.5 P ercent ) with uranium recovery (90.8 P ercent ) and their separation from the lanthanides were attained at 70-80 d egree C during l-2h. The extraction of lanthanides in carbonate solution was low and did not exceed 4.6 P ercent .

  16. Contributions to the thorium occupational exposure in Brazil

    International Nuclear Information System (INIS)

    Cunha, Kenya Moore de Almeida Dias da

    1997-01-01

    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)

  17. Potency of Thorium and Uranium in West Bangka Region

    International Nuclear Information System (INIS)

    Ngadenin; Heri Syaeful; Kurnia Setiawan Widana; Muhammad Nurdin

    2014-01-01

    Thorium and uranium in Bangka Island are mainly found in monazite mineral. In the geological point of view the monazite formed in S type granite, sandstones and alluvial deposits. In Bangka Barat where several S types granite and also alluvial deposits and this area considered as a potential area for monazite placer. S type granites are predicted as a source of monazite while alluvial deposits are considered as a dispersion place for deposition of monazite. The purpose of this study is to determine the geological information and to know the hypothetical potency of thorium and uranium resources in alluvial deposits. The methods used in this study are geological mapping, measurement of thorium and uranium contents in the rock, sampling of granite for petrographic analysis, sampling of heavy mineral in alluvial deposits for grain size analysis. Results of the research show that the lithology of West Bangka region composed of schist unit, meta-sandstone unit, granite intrusion, diabase intrusion, sandstone unit and alluvial deposits. Monazite is found in granite intrusion, sandstone unit and alluvial deposits. Evolving fault strand to northwest-southeast, northeast-southwest and west-east. The results of the grain size analysis of heavy mineral shows the average percentage of monazite in the heavy mineral is 6.34%. Other potential minerals contained in placer deposits are zircon 36.65%, ilmenite 19.67% and cassiterite 14.75%. (author)

  18. Sorption behaviour of uranium and thorium on cryptomelane-type hydrous manganese dioxide from aqueous solution

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; El-Absy, M.A.; Abdel-Hamid, M.M.; Aly, H.F.

    1993-01-01

    The kinetics of sorption of uranium and thorium from aqueous nitrate solutions on cryptomelane-type hydrous manganese dioxide (CRYMO) was studied. The exchange of uranium is particle diffusion controlled while that of thorium is chemical reaction at the exchange sites. Sorption of uranium and thorium by CRYMO has been also studied as a function of metal concentrations and temperature. The sorption of both cations is found to be an endothermic process and increases markedly with temperature between 30 and 60 degree C. The sorption results have been analysed by the langmuir adsorption isotherm over the entire range of uranium and thorium concentrations investigated. 35 refs., 8 figs., 5 tabs

  19. Remeasurement of thorium-230 in the pore water of Lacnor tailings

    International Nuclear Information System (INIS)

    Snodgrass, W.J.; Hart, D.R.

    1990-02-01

    A resampling of the Lacnor tailings management area was undertaken under a comprehensive quality assurance programme to establish levels of thorium 230 in pore water. A quality assurance programme was established for field sampling, sample handling and transport, and laboratory procedures and reporting. The external audit was used to evaluate analytical bias (on synthetic and field samples) and precision (by comparison of duplicate-duplicate results). Accuracy was assessed using synthetic samples. The external audit indicates that thorium 230 measurements by the main laboratory are not significantly different from the interlaboratory average within standard statistical limits. The results of the audit are based on measurement of environmental samples and known synthetic samples. This shows that present and previous measurements of thorium 230 varying from 0,1 to 150 Bq/L are valid data. A qualitative interpretation of the controls on thorium 230 geochemistry is provided in terms of control by thorium 232 and thorium dioxide(c) solid phase. Generic dose estimates for consumption of water containing thorium 230 are made but require refinement ot account for the actual pH of the drinking water and the degree of dilution of the pore water. The results of this project indicate that the performance of the laboratory that will conduct future thorium 230 measurements can be assessed satisfactorily with a smaller scale external laboratory assurance programme. The programme should include replicate samples sent to each laboratory and interlaboratory comparison on samples having high and low values of thorium 230

  20. Partial thorium loading in the initial core of Kakrapar atomic power reactor

    International Nuclear Information System (INIS)

    Balakrishnan, M.R.

    1993-01-01

    The first unit of Kakrapar nuclear power station has gone critical with some thorium oxide fuel bundles loaded in its core. The thorium helps to flatten the power by reducing neutron flux in the centre of the reactor. However, the placing of the thorium had to be planned with care, because if the neutron flux at a point where a safety rod is located is depressed, the reactivity worth of the safety rod gets reduced. Using a dynamic programing approach, the Reactor Engineering Division of Bhabha Atomic Research Centre worked out a satisfactory configuration for loading the thorium bundles

  1. Simultaneous determination of uranium and thorium with Arsenazo III by second-derivative spectrophotometry

    International Nuclear Information System (INIS)

    Kuroda, Rokuro; Kurosaki, Mayumi; Hayashibe, Yutaka; Ishimaru, Satomi

    1990-01-01

    A derivative spectrophotometric method has been developed for the simultaneous determination of microgram quantities of uranium and thorium with Arsenazo III in hydrochloric acid medium. The second-derivative absorbances of the uranium and thorium Arsenazo III complexes at 679.5 and 684.4 nm are used for their quantification. Uranium and thorium, both in the range 0.1-0.7 μg/ml have been determined simultaneously with good precision. The procedure does not require separation of uranium and thorium, and allows the determination of both metals in the presence of alkaline-earth metals and zirconium, but lanthanides interfere. (author)

  2. Thorium determination by X-ray Fluorescence Spectrometry in simulated thorex process solutions

    International Nuclear Information System (INIS)

    Yamaura, M.; Matsuda, H.T.

    1989-01-01

    The X-ray fluorescence method for thorium determination in aqueous and organic (TBP-n-dodecane) solutions is described. The thin film-technique for sample preparation and a suitable internal standard have been used. Some parameters as analytical line, internal standard, filter paper, paper geometry, sample volume and measurement conditions were studied. Uranium, fission products, corrosion products and thorex reagent components were studied as interfering elements in the thorium analysis, as well as the matrix effect by using the thorex process simulated solutions the method to thorium determination in irradiated thorium solutions was applied. (M.J.C.) [pt

  3. Strep-Tagged Protein Purification.

    Science.gov (United States)

    Maertens, Barbara; Spriestersbach, Anne; Kubicek, Jan; Schäfer, Frank

    2015-01-01

    The Strep-tag system can be used to purify recombinant proteins from any expression system. Here, protocols for lysis and affinity purification of Strep-tagged proteins from E. coli, baculovirus-infected insect cells, and transfected mammalian cells are given. Depending on the amount of Strep-tagged protein in the lysate, a protocol for batch binding and subsequent washing and eluting by gravity flow can be used. Agarose-based matrices with the coupled Strep-Tactin ligand are the resins of choice, with a binding capacity of up to 9 mg ml(-1). For purification of lower amounts of Strep-tagged proteins, the use of Strep-Tactin magnetic beads is suitable. In addition, Strep-tagged protein purification can also be automated using prepacked columns for FPLC or other liquid-handling chromatography instrumentation, but automated purification is not discussed in this protocol. The protocols described here can be regarded as an update of the Strep-Tag Protein Handbook (Qiagen, 2009). © 2015 Elsevier Inc. All rights reserved.

  4. Bioinspired Materials for Water Purification

    Directory of Open Access Journals (Sweden)

    Alfredo Gonzalez-Perez

    2016-06-01

    Full Text Available Water scarcity issues associated with inadequate access to clean water and sanitation is a ubiquitous problem occurring globally. Addressing future challenges will require a combination of new technological development in water purification and environmental remediation technology with suitable conservation policies. In this scenario, new bioinspired materials will play a pivotal role in the development of more efficient and environmentally friendly solutions. The role of amphiphilic self-assembly on the fabrication of new biomimetic membranes for membrane separation like reverse osmosis is emphasized. Mesoporous support materials for semiconductor growth in the photocatalytic degradation of pollutants and new carriers for immobilization of bacteria in bioreactors are used in the removal and processing of different kind of water pollutants like heavy metals. Obstacles to improve and optimize the fabrication as well as a better understanding of their performance in small-scale and pilot purification systems need to be addressed. However, it is expected that these new biomimetic materials will find their way into the current water purification technologies to improve their purification/removal performance in a cost-effective and environmentally friendly way.

  5. Methodology of simultaneous analysis of Uranium and Thorium by nuclear and atomic techniques. Application to the Uranium and Thorium dosing in mineralogic samples

    International Nuclear Information System (INIS)

    Fakhi, S.

    1988-01-01

    This work concerns essentially the potential applications of 100 kW nuclear reactor of Strasbourg Nuclear Research Centre to neutron activation analysis of Uranium and Thorium. The Uranium dosing has been made using: 239-U, 239-Np, fission products or delayed neutrons. Thorium has been showed up by means of 233-Th or 233-Pa. The 239-U and 233-Th detection leads to a rapid and non-destructive analysis of Uranium and Thorium. The maximum sensitivity is of 78 ng for Uranium and of 160 ng for Thorium. The Uranium and Thorium dosing based on 239-Np and 233-Pa detection needs chemical selective separations for each of these radionuclides. The liquid-liquid extraction has permitted to elaborate rapid and quantitative separation methods. The sensitivities of the analysis after extraction reach 30 ng for Uranium and 50 ng for Thorium. The fission products separation study has allowed to elaborate the La, Ce and Nd extractions and its application to the Uranium dosing gives satisfying results. A rapid dosing method with a sensitivity of 0.35 microgramme has been elaborated with the help of delayed neutrons measurement. These different methods have been applied to the Uranium and Thorium dosing in samples coming from Oklo mine in Gabon. The analyses of these samples by atomic absorption spectroscopy and by the proton induced X-ray emission (PIXE) method confirm that the neutron activation analysis methods are reliable. 37 figs., 14 tabs., 50 refs

  6. Sequential extraction procedure for determination of uranium, thorium, radium, lead and polonium radionuclides by alpha spectrometry in environmental samples

    Science.gov (United States)

    Oliveira, J. M.; Carvalho, F. P.

    2006-01-01

    A sequential extraction technique was developed and tested for common naturally-occurring radionuclides. This technique allows the extraction and purification of uranium, thorium, radium, lead, and polonium radionuclides from the same sample. Environmental materials such as water, soil, and biological samples can be analyzed for those radionuclides without matrix interferences in the quality of radioelement purification and in the radiochemical yield. The use of isotopic tracers (232U, 229Th, 224Ra, 209Po, and stable lead carrier) added to the sample in the beginning of the chemical procedure, enables an accurate control of the radiochemical yield for each radioelement. The ion extraction procedure, applied after either complete dissolution of the solid sample with mineral acids or co-precipitation of dissolved radionuclide with MnO2 for aqueous samples, includes the use of commercially available pre-packed columns from Eichrom® and ion exchange columns packed with Bio-Rad resins, in altogether three chromatography columns. All radioactive elements but one are purified and electroplated on stainless steel discs. Polonium is spontaneously plated on a silver disc. The discs are measured using high resolution silicon surface barrier detectors. 210Pb, a beta emitter, can be measured either through the beta emission of 210Bi, or stored for a few months and determined by alpha spectrometry through the in-growth of 210Po. This sequential extraction chromatography technique was tested and validated with the analysis of certified reference materials from the IAEA. Reproducibility was tested through repeated analysis of the same homogeneous material (water sample).

  7. ATBR - a thorium breeder reactor concept for an early induction of thorium

    International Nuclear Information System (INIS)

    Jagannathan, V.; Pal, Usha; Karthikeyan, R.; Ganesan, S.; Jain, R.P.; Kamat, S.U.

    1999-07-01

    A new reactor concept has been proposed for induction of thorium in an enriched uranium reactor. The neutronic characteristics of the fissile and fertile materials, have been exploited to arrive at optimal fuel assembly and core configurations. Each fuel assembly consists of an enriched uranium seed zone and a thoria blanket zone. They are in the form, of ring type fuel clusters. The fuel is contained in vertical pressure tubes placed in a hexagonal lattice array in D 2 O moderator. Boiling H 2 O coolant is used. The 235 U enrichment is about 5%. The thoria rods contain the 233 U bred in situ by irradiation of one batch load of mere thoria clusters (without the seed zone) for one fuel cycle in the same reactor. There is no need for external feed enrichment in thoria rods. Additionally some moveable thoria clusters are used for the purpose of xenon over-ride. The fissile production rate from the fertile material and the consumption rate of fissile inventory is judiciously balanced by the choice of U/Th fuel rod dia, the number and location of thoria rods in the fuel assembly and in the core. During steady state operation at rated power level, there in no need for any conventional control maneuvers such as change in soluble boron concentration or control rod movement as a function of burnup. Burnable poison rods are also not required. A very small reactivity fluctuation of ±2 mk in 300 effective full power days of operation is achieved and can be nearly met by coolant inlet enthalpy changes or moveable thoria clusters. Control is required only for cold shutdown of the reactor. The uranium as well as thoria rods achieve a fairly high burnup of 30-35 GWD/T at the time of discharge. Since the excess reactivity for hot full power operation is nearly zero at all time during the fuel cycle and since the coefficients of reactivity due to temperature and density variations of coolant are nearly zero by design, there is hardly any possibility of severe accidents involving

  8. Sodium purification in Rapsodie; La purification du sodium a Rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Giraud, B [Commissariat a l' Energie Atomique, Dir. des Piles Atomiques, Cadarache (France). Centre d' Etudes Nucleaires

    1968-07-01

    This report is one of a series of publications presenting the main results of tests carried out during the start-up of the first french fast neutron reactor: Rapsodie. The article presents the sodium purification techniques used in the reactor cooling circuits both from the constructional point of view and with respect to results obtained during the first years working. (author) [French] Ce rapport fait partie d'une serie de publications presentant l'essentiel des resultats des essais effectues a l'occasion du demarrage du premier reacteur francais a neutrons rapides: RAPSODIE. Cet article expose les techniques de la purification du sodium utilise dans les circuits de refroidissement du reacteur tant au point de vue de leur realisation technologique, que des resultats obtenus pendant la premiere annee de fonctionnement. (auteur)

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

    International Nuclear Information System (INIS)

    Ishiguro, Y.

    1986-10-01

    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.)

  10. Determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Le Cong; Tao, Chau Van; Thong, Luong Van; Linh, Duong Mong [University of Science Ho Chi Minh City (Viet Nam). Faculty of Physics and Engineering Physics; Dong, Nguyen Van [University of Science Ho Chi Minh City (Viet Nam). Faculty of Chemistry

    2011-08-15

    In this study, a simple procedure for the determination of natural uranium, thorium and radium isotopes in water and soil samples by alpha spectroscopy is described. This procedure allows a sequential extraction polonium, uranium, thorium and radium radionuclides from the same sample in two to three days. It was tested and validated with the analysis of certified reference materials from the IAEA. (orig.)

  11. An extraction method of uranium 233 from the thorium irradiates in a reactor core

    International Nuclear Information System (INIS)

    Chesne, A.; Regnaut, P.

    1955-01-01

    Description of the conditions of separation of the thorium, of the uranium 233 and of the protactinium 233 in hydrochloric solution by absorption then selective elution on anion exchange resin. A precipitation of the thorium by the oxalic acid permits the recuperation of the hydrochloric acid which is recycled, the main, raw material consumed being the oxalic acid. (authors) [fr

  12. Demonstration of iron and thorium in autopsy tissues by x-ray microanalysis

    International Nuclear Information System (INIS)

    Landas, S.; Turner, J.W.; Moore, K.C.; Mitros, F.A.

    1984-01-01

    We performed x-ray microanalysis of autopsy specimens using a scanning-transmission electron microscopy mode. Tissues were obtained at necropsy from a patient with history of angiography using thorium dioxide and from a patient with hemochromatosis. X-ray microanalysis confirmed the presence of thorium and iron in their respective tissues. Effects of staining reagents were examined

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

    International Nuclear Information System (INIS)

    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

  14. A passive technique using SSNTDs for Estimation of thorium to uranium ratios in rocks

    International Nuclear Information System (INIS)

    Kenawy, M.A.; Sayyah, T.A.; Said, A.F.; Hafez, A.F.

    2005-01-01

    A passive technique using plastic nuclear track detectors (CR-39 and LR-115) is presented to estimate Th/U ratios and consequently the thorium and uranium content in granites taken from uranium exploration mines in Egyptian desert. The registration sensitivities of both CR-39 and LR-115 detector for close contact alpha-radiography uranium and thorium concentrations in ppm were computed

  15. Durability of adhesive bonds to uranium alloys, tungsten, tantalum, and thorium

    International Nuclear Information System (INIS)

    Childress, F.G.

    1975-01-01

    Long-term durability of epoxy bonds to alloys of uranium (U-Nb and Mulberry), nickel-plated uranium, thorium, tungsten, tantalum, tantalum--10 percent tungsten, and aluminum was evaluated. Significant strengths remain after ten years of aging; however, there is some evidence of bond deterioration with uranium alloys and thorium stored in ambient laboratory air

  16. Inhalation radiotoxicity of irradiated thorium as a heavy water reactor fuel

    International Nuclear Information System (INIS)

    Edwards, G.W.R.; Priest, N.D.; Richardson, R.B.

    2013-01-01

    The online refueling capability of Heavy Water Reactors (HWRs), and their good neutron economy, allows a relatively high amount of neutron absorption in breeding materials to occur during normal fuel irradiation. This characteristic makes HWRs uniquely suited to the extraction of energy from thorium. In Canada, the toxicity and radiological protection methods dealing with personnel exposure to natural uranium (NU) spent fuel (SF) are well-established, but the corresponding methods for irradiated thorium fuel are not well known. This study uses software to compare the activity and toxicity of irradiated thorium fuel ('thorium SF') against those of NU. Thorium elements, contained in the inner eight elements of a heterogeneous high-burnup bundle having LEU (Low-enriched uranium) in the outer 35 elements, achieve a similar burnup to NU SF during its residence in a reactor, and the radiotoxicity due to fission products was found to be similar. However, due to the creation of such inhalation hazards as U-232 and Th-228, the radiotoxicity of thorium SF was almost double that of NU SF after sufficient time has passed for the decay of shorter-lived fission products. Current radio-protection methods for NU SF exposure are likely inadequate to estimate the internal dose to personnel to thorium SF, and an analysis of thorium in fecal samples is recommended to assess the internal dose from exposure to this fuel. (authors)

  17. Inhalation radiotoxicity of irradiated thorium as a heavy water reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, G.W.R.; Priest, N.D.; Richardson, R.B. [Atomic Energy of Canada Ltd., Chalk River, Ontario, K0J 1J0 (Canada)

    2013-07-01

    The online refueling capability of Heavy Water Reactors (HWRs), and their good neutron economy, allows a relatively high amount of neutron absorption in breeding materials to occur during normal fuel irradiation. This characteristic makes HWRs uniquely suited to the extraction of energy from thorium. In Canada, the toxicity and radiological protection methods dealing with personnel exposure to natural uranium (NU) spent fuel (SF) are well-established, but the corresponding methods for irradiated thorium fuel are not well known. This study uses software to compare the activity and toxicity of irradiated thorium fuel ('thorium SF') against those of NU. Thorium elements, contained in the inner eight elements of a heterogeneous high-burnup bundle having LEU (Low-enriched uranium) in the outer 35 elements, achieve a similar burnup to NU SF during its residence in a reactor, and the radiotoxicity due to fission products was found to be similar. However, due to the creation of such inhalation hazards as U-232 and Th-228, the radiotoxicity of thorium SF was almost double that of NU SF after sufficient time has passed for the decay of shorter-lived fission products. Current radio-protection methods for NU SF exposure are likely inadequate to estimate the internal dose to personnel to thorium SF, and an analysis of thorium in fecal samples is recommended to assess the internal dose from exposure to this fuel. (authors)

  18. 75 FR 71677 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2010-11-24

    ... DEPARTMENT OF ENERGY Reimbursement for Costs of Remedial Action at Active Uranium and Thorium... in FY 2011 from eligible active uranium and thorium processing site licensees for reimbursement under... approximately $24.3 million of Recovery Act funds available for reimbursement in FY 2011, as well as the $10...

  19. 76 FR 30696 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-26

    ... in the reimbursement ceilings). Title X requires DOE to reimburse eligible uranium and thorium... DEPARTMENT OF ENERGY Reimbursement for Costs of Remedial Action at Active Uranium and Thorium... reimbursement under Title X of the Energy Policy Act of 1992. In our Federal Register Notice of November 24...

  20. 76 FR 24871 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2011-05-03

    ... in the reimbursement ceilings). Title X requires DOE to reimburse eligible uranium and thorium... DEPARTMENT OF ENERGY Reimbursement for Costs of Remedial Action at Active Uranium and Thorium... reimbursement under Title X of the Energy Policy Act of 1992. DATES: In our Federal Register Notice of November...

  1. United States Geological Survey: uranium and thorium resource assessment and exploration research program, fiscal year 1979

    International Nuclear Information System (INIS)

    Offield, T.W.

    1978-01-01

    Objectives and current plans are given for the following projects: uranium geochemistry and mineralogy; uranium in sedimentary environments; uranium in igneous and metamorphic environments; geophysical techniques in uranium and thorium exploration; and thorium investigations and resource assessment. Selected noteworthy results of FY 1978 research are given

  2. Experiences in running solvent extraction plant for thorium compounds [Paper No. : V-5

    International Nuclear Information System (INIS)

    Gopalkrishnan, C.R.; Bhatt, J.P.; Kelkar, G.K.

    1979-01-01

    Indian Rare Earths Ltd. operates a Plant using thorium concentrates as raw material, employing hydrocarbonate route, for the manufacture of thorium compounds. A small demonstration solvent extraction plant designed by the Chemical Engineering Division, B.A.R.C. is also being operated for the same purpose using a partly purified thorium hydrocarbonate as raw material. In the solvent extraction process, separation of pure thorium is done in mixer settlers using 40% mixture of tri-butyl phosphate in kerosene. Though a comparatively purer raw material of hydrocarbonate than thorium concentrate is used, heavy muck formation is encountered in the extraction stage. Production of nuclear grade thorium oxide has been successful so far as quality is concerned. The quality of thorium nitrate suffers in the yellow colouration and high phosphate content, the former being only partly controlled through the use of pretreated kerosene. When a larger solvent extraction plant is to be designed to use thorium concentrates as raw material, some of the problems encountered will be considered. (author)

  3. New twists and turns for actinide chemistry. Organometallic infinite coordination polymers of thorium diazide

    Energy Technology Data Exchange (ETDEWEB)

    Monreal, Marisa J.; Seaman, Lani A.; Goff, George S.; Michalczyk, Ryszard; Morris, David E.; Scott, Brian L.; Kiplinger, Jaqueline L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2016-03-07

    Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

  4. Operation of CANDU power reactor in thorium self-sufficient fuel cycle

    Indian Academy of Sciences (India)

    This paper presents the results of calculations for CANDU reactor operation in thorium fuel cycle. Calculations are performed to estimate the feasibility of operation of heavy-water thermal neutron power reactor in self-sufficient thorium cycle. Parameters of active core and scheme of fuel reloading were considered to be the ...

  5. Investigations on the elution behaviour of TOPO complexes of uranium and thorium using supercritical fluid chromatography

    International Nuclear Information System (INIS)

    Kumar, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2004-01-01

    In summary uranium and thorium could be separated by supercritical fluid chromatography technique as their TOPO complexes. The elution profiles with pre-complexation of the metal nitrate indicate a better separation than the in-situ complexation. The technique can also be employed for the assay of uranium and thorium at low levels

  6. Short history of radioactivity. No. XIII. The actinium and thorium series

    Energy Technology Data Exchange (ETDEWEB)

    Chalmers, T W

    1950-06-16

    Discussions of the actinium disintegration series (about 1905), the /sup 235/U or actinium series (as it is accepted today), the disintegration of thorium (about 1905), the thorium series in the modern form, and the 4n, 4n + 1, 4n + 2, and 4n + 3 series are presented.

  7. Hazard Classification for Fuel Supply Shutdown Facility

    International Nuclear Information System (INIS)

    BENECKE, M.W.

    2000-01-01

    Final hazard classification for the 300 Area N Reactor fuel storage facility resulted in the assignment of Nuclear Facility Hazard Category 3 for the uranium metal fuel and feed material storage buildings (303-A, 303-B, 303-G, 3712, and 3716). Radiological for the residual uranium and thorium oxide storage building and an empty former fuel storage building that may be used for limited radioactive material storage in the future (303-K/3707-G, and 303-E), and Industrial for the remainder of the Fuel Supply Shutdown buildings (303-F/311 Tank Farm, 303-M, 313-S, 333, 334 and Tank Farm, 334-A, and MO-052)

  8. Potentialities and practical limitations of absolute neutron dosimetry using thin films of uranium and thorium applied to the fission track dating

    CERN Document Server

    Bigazzi, G; Hadler-Neto, J C; Iunes, P J; Paulo, S R; Oddone, M; Osorio, A M A; Zúñiga, A G

    1999-01-01

    Neutron dosimetry using natural uranium and thorium thin films makes possible that mineral dating by the fission-track method can be accomplished, even when poor thermalized neutron facilities are employed. In this case, the contributions of the fissions of sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 8 U and sup 2 sup 3 sup 2 Th induced by thermal, epithermal and fast neutrons to the population of tracks produced during irradiation are quantified through the combined use of natural uranium and thorium films. If the Th/U ratio of the sample is known, only one irradiation (where the sample and the films of uranium and thorium are present) is necessary to perform the dating. However, if that ratio is unknown, it can be determined through another irradiation where the mineral to be dated and both films are placed inside a cadmium box. Problems related with film manufacturing and calibration are discussed. Special attention is given to the utilization of thin films having very low uranium content. The problems faced sugg...

  9. Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides in phosphate rocks and phosphate fertilizers

    Energy Technology Data Exchange (ETDEWEB)

    Komura, K; Yanagisawa, M; Sakurai, J; Sakanoue, M

    1985-10-01

    Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides have been studied for 2 phosphate rocks and 7 phosphate fertilizers. Uranium contents were found to be rather high (39-117 ppm) except for phosphate rock from Kola. The uranium series nuclides were found to be in various equilibration states, which can be grouped into following three categories. Almost in the equilibrium state, 238U approximately 230Th greater than 210Pb greater than 226Ra and 238U greater than 230Th greater than 210Pb greater than 226Ra. Thorium contents were found to be, in general, low and appreciable disequilibrium of the thorium series nuclides was not observed except one sample. Potassium contents were also very low (less than 0.3% K2O) except for complex fertilizers. Based on the present data, discussions were made for the radiation exposure due to phosphate fertilizers.

  10. Fast Thorium Molten Salt Reactors Started with Plutonium

    International Nuclear Information System (INIS)

    Merle-Lucotte, E.; Heuer, D.; Le Brun, C.; Brissot, R.; Liatard, E.; Meplan, O.; Nuttin, A.; Mathieu, L.

    2006-01-01

    One of the pending questions concerning Molten Salt Reactors based on the 232 Th/ 233 U fuel cycle is the supply of the fissile matter, and as a consequence the deployment possibilities of a fleet of Molten Salt Reactors, since 233 U does not exist on earth and is not yet produced in the current operating reactors. A solution may consist in producing 233 U in special devices containing Thorium, in Pressurized Water or Fast Neutrons Reactors. Two alternatives to produce 233 U are examined here: directly in standard Molten Salt Reactors started with Plutonium as fissile matter and then operated in the Th/ 233 U cycle; or in dedicated Molten Salt Reactors started and fed with Plutonium as fissile matter and Thorium as fertile matter. The idea is to design a critical reactor able to burn the Plutonium and the minor actinides presently produced in PWRs, and consequently to convert this Plutonium into 233 U. A particular reactor configuration is used, called 'unique channel' configuration in which there is no moderator in the core, leading to a quasi fast neutron spectrum, allowing Plutonium to be used as fissile matter. The conversion capacities of such Molten Salt Reactors are excellent. For Molten Salt Reactors only started with Plutonium, the assets of the Thorium fuel cycle turn out to be quickly recovered and the reactor's characteristics turn out to be equivalent to Molten Salt Reactors operated with 233 U only. Using a combination of Molten Salt Reactors started or operated with Plutonium and of Molten Salt Reactors started with 233 U, the deployment capabilities of these reactors fully satisfy the condition of sustainability. (authors)

  11. Kinetic study of the thorium phosphate - diphosphate dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Dacheux, N.; Thomas, A.C.; Brandel, V.; Genet, M. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Aupiais, J. [CEA/DAM-Ile de France, Dept. Analyse Surveillance Environnement, DASE, Service Radioanalyses Chimie Environnement, 91 - Bruyeres-Le-Chatel (France)

    2000-07-01

    The thorium phosphate-diphosphate Th{sub 4}(PO{sub 4}){sub 4}P{sub 2}O{sub 7} (TPD) structure allows the replacement of large amounts of thorium by tetravalent actinides leading to the formation of solid solutions. This compound was obtained in powdered or sintered form after pressing at room temperature at 300-800 MPa then heating at 1250 deg. C for 10-30 hours. The resistance of this material to aqueous corrosion was determined by varying several parameters such as surface, leaching flow, acidity or temperature. It was thus possible to independently determine the influence of each parameter on the leaching rate provided that the saturation of the solution was not obtained. In acidic media, the partial order related to [H{sub 3}O{sup +}] was found to be in the 0.31-0.35 range while, in basic media, the partial order related to [OH{sup -}] was almost the same (0.45). The activation energy (42 kJ/mol) was determined between 4 deg. C and 120 deg. C. Moreover, the addition of phosphate in the leachate slightly increased the TPD dissolution rate. When the saturation of the solution is reached, a gelatinous precipitate controls the thorium and phosphate concentrations. The complete characterization of this solid led to the proposed general formula Th{sub 2}(PO{sub 4}){sub 2}(HPO{sub 4}). n H{sub 2}O which conventional solubility product (at I = 0 M) is very low: K{sup *}{sub S,0} 10{sup -66.6{+-}}{sup 1.2} even in very acidic media. (authors)

  12. Thermal diffusivity and conductivity of thorium- uranium mixed oxides

    Science.gov (United States)

    Saoudi, M.; Staicu, D.; Mouris, J.; Bergeron, A.; Hamilton, H.; Naji, M.; Freis, D.; Cologna, M.

    2018-03-01

    Thorium-uranium oxide pellets with high densities were prepared at the Canadian Nuclear Laboratories (CNL) by co-milling, pressing, and sintering at 2023 K, with UO2 mass contents of 0, 1.5, 3, 8, 13, 30, 60 and 100%. At the Joint Research Centre, Karlsruhe (JRC-Karlsruhe), thorium-uranium oxide pellets were prepared using the spark plasma sintering (SPS) technique with 79 and 93 wt. % UO2. The thermal diffusivity of (Th1-xUx)O2 (0 ≤ x ≤ 1) was measured at CNL and at JRC-Karlsruhe using the laser flash technique. ThO2 and (Th,U)O2 with 1.5, 3, 8 and 13 wt. % UO2 were found to be semi-transparent to the infrared wavelength of the laser and were coated with graphite for the thermal diffusivity measurements. This semi-transparency decreased with the addition of UO2 and was lost at about 30 wt. % of UO2 in ThO2. The thermal conductivity was deduced using the measured density and literature data for the specific heat capacity. The thermal conductivity for ThO2 is significantly higher than for UO2. The thermal conductivity of (Th,U)O2 decreases rapidly with increasing UO2 content, and for UO2 contents of 60% and higher, the conductivity of the thorium-uranium oxide fuel is close to UO2. As the mass difference between the Th and U atoms is small, the thermal conductivity decrease is attributed to the phonon scattering enhanced by lattice strain due to the introduction of uranium in ThO2 lattice. The new results were compared to the data available in the literature and were evaluated using the classical phonon transport model for oxide systems.

  13. The Effective Resonance Integral of Thorium Oxide Rods

    Energy Technology Data Exchange (ETDEWEB)

    Weitman, J

    1962-12-15

    The effective resonance integral of thorium oxide rods has been determined as a function of their surface to mass ratio. The range of S/M values covered is 0.15 - 0.65 cm/g. An experimental technique based on the comparison of activities obtained in thermal and slowing-down neutron fluxes was employed. The shape of the resonance neutron spectrum was determined from measurements with a fast chopper and from calculations, permitting deduction of a correction factor which relates the experimental values to the ideal 1/E case. The results are summarized by the following expression: RI{sub ThO{sub 2}} (5.0 + 15.6{radical}(S/M{sub ThO{sub 2}})) {+-} 5% The main contribution to the margin of error arises from the uncertainties in the 1.5 % spectral correction applied in the 1.5 b '1/v' part deducted and in the 1520 b infinite dilution integral of gold, used as a standard. In order to compare the consistency of Dresner's first equivalence theorem and Nordheim's numerical calculations relative to our results, the resonance integral values for thorium metal rods obtained previously by Hellstrand and Weitman have been recalculated, using recent cross section and spectrum data. The new formula is Rl{sub Th} = (3.3 + 16.1{radical}(S/M{sub Th})) {+-} 5%. It differs from the old one mainly because of the proved non-1/v behaviour of the thorium cross section below the first resonance.

  14. Water purification using organic salts

    Science.gov (United States)

    Currier, Robert P.

    2004-11-23

    Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.

  15. The bubble method of water purification

    Science.gov (United States)

    Smirnov, B. M.; Babaeva, N. Yu.; Naidis, G. V.; Panov, V. A.; Saveliev, A. S.; Son, E. E.; Tereshonok, D. V.

    2018-02-01

    The processes of water purification from admixture molecules are analyzed. The purification rate is limited due to a low diffusion coefficient of the admixture molecules in water. At non-small concentrations of the admixture molecules, the water purication can proceed through association of molecules in condensed nanoparticles which fall on the bottom of the water volume. The rate of association may be increased in an external electric field, but in reality this cannot change significantly the rate of the purification process. The bubble method of water purification is considered, where air bubbles formed at the bottom of the water volume, transfer admixture molecules to the interface. This method allows one to clean small water volumes fast. This mechanism of water purification is realized experimentally and exhibits the promises of the bubble purification method.

  16. Preliminary design needs for pilot plant of Monazite processing into Thorium Oxide (ThO_2)

    International Nuclear Information System (INIS)

    Hafni Lissa Nuri; Prayitno; Abdul Jami; M-Pancoko

    2014-01-01

    Data and information collection aimed in order to meet the needs of the initial design for pilot plant of monazite processing into thorium oxide (ThO_2). The content of thorium in monazite is high in Indonesia between 2.9 to 4.1% and relatively abundant in Bangka Belitung Islands. Thorium can be used as fuel because of its potential is more abundant instead of uranium. Plant of thorium oxide commercially from monazite established starting from pilot uranium. Plant of thorium oxide commercially from monazite established starting from pilot plant in order to test laboratory data. Pilot plant design started from initial design, basic design, detailed design, procurement and construction. Preliminary design needs includes data feed and products, a block diagram of the process, a description of the process, the determination of process conditions and type of major appliance has been conducted. (author)

  17. Uranium and thorium recovery from a sub-product of monazite industrial processing

    International Nuclear Information System (INIS)

    Gomiero, L.A.; Ribeiro, J.S.; Scassiotti Filho, W.

    1994-01-01

    In the monazite alkaline leaching industrial process for the production of rare earth elements, a by-product is formed, which has a high concentration of thorium and a lower but significant one of uranium. A procedure for recovery of the thorium and uranium contents in this by-product is presented. The first step of this procedure is the leaching with sulfuric acid, followed by uranium extraction from the acid liquor with a tertiary amine, stripping with a Na Cl solutions and precipitation as ammonium diuranate with N H 4 O H. In order to obtain thorium concentrates with higher purity, it is performed by means of the extraction of thorium from the acid liquor, with a primary amine, stripping by a Na Cl solution and precipitation as thorium hydroxide or oxalate. (author)

  18. Recovery of thorium along with uranium 233 from Thorex waste solution employing Chitosan

    International Nuclear Information System (INIS)

    Priya, S.; Reghuram, D.; Kumaraguru, K.; Vijayan, K.; Jambunathan, U.

    2003-01-01

    The low level waste solution, generated from Thorex process during the processing of U 233 , contains thorium along with traces of Th 228 and U 233 . Chitosan, a natural bio-polymer derived from Chitin, was earlier used to recover the uranium and americium. The studies were extended to find out its thorium sorption characteristics. Chitosan exhibited very good absorption of thorium (350 mg/g). Chitosan was equilibrated directly with the low level waste solution at different pH after adjusting its pH, for 60 minutes with a Chitosan to aqueous ratio of 1:100 and the raffinates were filtered and analysed. The results showed more than 99% of thorium and U 233 could be recovered by Chitosan between pH 4 and 5. Loaded thorium and uranium could be eluted from the Chitosan by 1M HNO 3 quantitatively. (author)

  19. Determination of uranium and thorium during chemical treatment of monazite

    International Nuclear Information System (INIS)

    El-Nadi, Y.A.; Daoud, J.A.; Aly, H.F.; Kregsamer, P.

    2000-01-01

    Total reflection x-ray fluorescence (TXRF) is a very useful technique for both qualitative and quantitative analysis because of its high detection power and its needed to small sample volumes (less than 100 μl are sufficient). In this work TXRF was used to determine the initial concentrations of the elements included in monazite sand and following up the chemical steps for treatment of monazite with special attention to uranium and thorium concentration as well as lanthanides. The results were compared to those obtained from EDXRF and ICP-MS techniques. (author)

  20. A Simplified Supercritical Fast Reactor with Thorium Fuel

    OpenAIRE

    Peng Zhang; Kan Wang; Ganglin Yu

    2014-01-01

    Super-Critical water-cooled Fast Reactor (SCFR) is a feasible option for the Gen-IV SCWR designs, in which much less moderator and thus coolant are needed for transferring the fission heat from the core compared with the traditional LWRs. The fast spectrum of SCFR is useful for fuel breeding and thorium utilization, which is then beneficial for enhancing the sustainability of the nuclear fuel cycle. A SCFR core is constructed in this work, with the aim of simplifying the mechanical structure ...

  1. 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)

  2. Concentrations of Uranium,Thorium and Potassium in Sweden

    International Nuclear Information System (INIS)

    Thunholm, Bo; Linden, Anders H.; Gustafsson, Bosse

    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. Uranium, thorium and radium in soil and crops

    International Nuclear Information System (INIS)

    Evans, S.; Eriksson, Aa.

    1983-06-01

    The distribution of the naturally occuring radionuclides uranium, thorium and radium in soil, plant material and drainage water was evaluated. The plant/soil concentration factors showed that very small fractions of the nuclides were available for the plants. The water/soil concentration factors were calculated; the nuclide content in drainage water generally indicated very low leaching rates. The distribution of the radionuclides was utilized with the aim to obtain reliable concentration factors which in turn could be used to calculate the transfer of nuclides within the agricultural ecosystem. Dose calculations were performed using plant/soil concentration factors based on geometric mean values. (authors)

  4. The electrodeposition of thorium in natural materials for alpha spectrometry

    International Nuclear Information System (INIS)

    Roman, D.

    1980-01-01

    A technique has been developed for the electrodeposition of thorium on stainless steel planchettes following standard radiochemical separation and uptake in acetate buffer. The method has been used on over 130 samples including calcrete, clay, granite and shell matrices. To assess the efficiency at ultra low levels, three solutions of carrier free 228 Th ( -7 μg in 5 ml electrolyte) and four solutions of 229 Th (4.4x10 -4 μg in 5 ml) were studied. The efficiencies of the former averaged 66 per cent; those of the 229 Th varied from 41 to 91%. (author)

  5. Measurement of uranium and thorium in marine sediments

    International Nuclear Information System (INIS)

    Denden, Ibtihel

    2009-01-01

    Lakes, oceans and seas accumulate sediments. These sediments constitute a file of the last environmental conditions going up in some cases to thousands of years. In our study, we consulted this file by analyzing radioisotopes of Uranium and Thorium that are included in a carrot of marine sediment taken from the south of Mediterranean Sea. When we applied the technique developed by the maritime environment's laboratory of Monaco, we found spectra with bad resolutions. For this reason, the optimization of this protocol appeared necessary. (Author).

  6. Design of a thorium fuelled Advanced Heavy Water Reactor

    International Nuclear Information System (INIS)

    Krishnani, P.D.

    2009-01-01

    Full text: The main objective for development of Advanced Heavy Water Reactor (AHWR) is to demonstrate thorium fuel cycle technologies, along with several other advanced technologies required for next generation reactors, so that these are readily available in time for launching the third stage. The AHWR under design is a 300 MWe vertical pressure tube type thorium-based reactor cooled by boiling light water and moderated by heavy water. The fuel consists of (Th-Pu)O 2 and ( 233 ThU)O 2 pins. The fuel cluster is designed to generate maximum energy out of 233 U, which is bred in-situ from thorium and has a slightly negative void coefficient of reactivity, negative fuel temperature coefficient and negative power coefficient. For the AHWR, the well -proven pressure tube technology and online fuelling have been adopted. Core heat removal is by natural circulation of coolant during normal operation and shutdown conditions. Thus, it combines the advantages of light water reactors and PHWRs and removes the disadvantages of PHWRs. It has several passive safety systems for reactor normal operation, decay heat removal, emergency core cooling, confinement of radioactivity etc. The fuel cycle is based on the in-situ conversion of naturally available thorium into fissile 233 U in self sustaining mode. The uranium in the spent fuel will be reprocessed and recycled back into the reactor. The plutonium inventory will be kept a minimum and will come from fuel irradiated in Indian PHWRs. The 233 U required initially can come from the fast reactor programme or it can be produced by specially designing the initial core of AHWR using (Th,Pu)MOX fuel. There will be gradual transition from the initial core which will not contain any 233 U to an equilibrium core, which will have ( 233 U, Th) MOX fuel pins also in a composite cluster. The self sustenance is being achieved by a differential fuel loading of low and a relatively higher Pu in the composite clusters. The AHWR burns the

  7. Brazil's uranium/thorium deposits: geology, reserves, potential

    International Nuclear Information System (INIS)

    McNeil, M.

    1979-01-01

    With its area of 8.5 million square kilometers (3.3 million square miles) Brazil is the world's fifth largest nation, occupying almost one half of the continent of South America. Its vastness and its wide variety of geological terrain suggest that parts of Brazil may be favorable for many kinds of uranium deposits. The nation's favorability for uranium is indicated by the high correspondence between discoveries and the amount of exploration done to date. For the first time, the uranium and thorium resources of Brazil and their geologic setting are described here in a single volume. 270 refs

  8. The Spondylarthritis Ankylopoietica and its treatment with thorium X

    International Nuclear Information System (INIS)

    Liska, G.

    1980-01-01

    After a detailed and comprehensive survey over the history of the spondylarthritis ankylopoietica or 'Bechterew's disease' and over the thorium X therapy, own experiences with patients are described. The patients received a Th-X therapy, supplemented by prednison phenylbutazone administration, with a total dose of up to 1000 to 2400 e.s. E. Th X. In addition, an intensive physicobalneologic and physiotherapeutic treatment was carried out. More than two thirds of the patients expressed their satisfaction with the results achieved. (DG) [de

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

    International Nuclear Information System (INIS)

    Barroso, D.E.G.

    1982-01-01

    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.) [pt

  10. 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.

  11. Thorium-d-metals compounds and solid solutions

    International Nuclear Information System (INIS)

    Chachkhiani, Z.B.; Chechernikov, V.I.; Chachkhiani, L.G.

    1986-01-01

    Thorium compounds with Fe, Co, Ni dependence of their magnetic properties on temperature, pressure and concentration of the second element are considered. Anomalous magnetic behaviour of alloys in the Th-Fe system is noted. Special attention is paid to compounds with CaCu 5 type hexagonal structure and their solid solutions. Th-Co-Ni specimens containing up to 25% Ni are ferromagnetics and the rest are paramagnetics. Specimens with 60% cobalt content do not display ferromagnetic properties up to 4.2 K. Hydrides of Th 7 M 3 H 30 type (M - Fe, Co, Ni) are also considered. Highly hydrogenized specimens (under high pressure) appear to be stronger ferromagnetics

  12. Light particles emitted with the fission fragments of thorium

    Energy Technology Data Exchange (ETDEWEB)

    San-Tsiang, T; Faraggi, H

    1947-01-01

    The traces produced by the fission of thorium with fast neutrons have been recorded photographically and studied. The formation of a light fragment of long range by either quadripartition or tripartition was not observed. The release of a short-range light fragment by bipartition was observed about one hundred times more frequently than was the release of such a fragment by tripartition. The ratio of the range of the two heavy fragments produced by tripartition was 1:2; this compares with a ratio of 1:3 for the heavy fragments produced by bipartition.

  13. 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.)

  14. Evaluation of plutonium, uranium, and thorium use in power reactor fuel cycles

    International Nuclear Information System (INIS)

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

    1977-01-01

    The increased cost of uranium and separative work has increased the attractiveness of plutonium use in both uranium and thorium fuel cycles in thermal reactors. A technology, fuel utilization, and economic evaluation is given for uranium and thorium fuel cycles in various reactor types, along with the use of plutonium and 238 U. Reactors considered are LWRs, HWRs, LWBRs, HTGRs, and FBRs. Key technology factors are fuel irradiation performance and associated physical property values. Key economic factors are unit costs for fuel fabrication and reprocessing, and for refabrication of recycle fuels; consistent cost estimates are utilized. In thermal reactors, the irradiation performance of ceramic fuels appears to be satisfactory. At present costs for uranium ore and separative work, recycle of plutonium with thorium rather than uranium is preferable from fuel utilization and economic viewpoints. Further, the unit recovery cost of plutonium is lower from LWR fuels than from natural-uranium HWR fuels; use of LWR product permits plutonium/thorium fueling to compete with uranium cycles. Converting uranium cycles to thorium cycles increases the energy which can be extracted from a given uranium resource. Thus, additional fuel utilization improvement can be obtained by fueling all thermal reactors with thorium, but this requires use of highly enriched uranium; use of 235 U with thorium is most economic in HTGRs followed by HWRs and then LWRs. Marked improvement in long-term fuel utilization can be obtained through high thorium loadings and short fuel cycle irradiations as in the LWBR, but this imposes significant economic penalties. Similar operating modes are possible in HWRs and HTGRs. In fast reactors, use of the plutonium-uranium cycle gives advantageous fuel resource utilization in both LMFBRs and GCFRs; use of the thorium cycle provides more negative core reactivity coefficients and more flexibility relative to use of recycle fuels containing uranium of less than 20

  15. Growth scenarios with thorium fuel cycles in pressurised heavy water reactors

    International Nuclear Information System (INIS)

    Balakrishnan, M.R.

    1991-01-01

    Since India has generous deposits of thorium, the availability of thorium will not be a limiting factor in any growth scenario. It is fairly well accepted that the best system for utilisation of thorium is the heavy water reactor. The growth scenarios possible using thorium in HWRs are considered. The base has been taken as 50,000 tons of natural uranium and practically unlimited thorium. The reference reactor has been assumed to be the PHWR, and all other growth scenarios are compared with the growth scenario provided by the once-through natural cycle in the PHWR. Two reactor types have been considered: the heavy water moderated, heavy water cooled, pressure tube reactor, known as the PHWR; and the heavy water moderated and cooled pressure vessel kind, similar to the ATUCHA reactor in Argentina. For each reactor, a number of different fuel cycles have been studied. All these cycles have been based on thorium. These are: the self-sustaining equilibrium thorium cycle (SSET); the high conversion ratio high burnup cycle; and the once through thorium cycle (OTT). The cycle have been initiated in two ways: one is by starting the cycle with natural uranium, reprocessing the spent fuel to obtain plutonium, and use that plutonium to initiate the thorium cycle; the other is to enrich the uranium to about 2-3% U-235 (the so-called Low Enriched Uranium or LEU), and use the LEU to initiate the thorium cycle. Both cases have been studied, and growth scenarios have been projected for every one of the possible combinations. (author). 1 tab

  16. Polyamide membranes with nanoscale Turing structures for water purification

    Science.gov (United States)

    Tan, Zhe; Chen, Shengfu; Peng, Xinsheng; Zhang, Lin; Gao, Congjie

    2018-05-01

    The emergence of Turing structures is of fundamental importance, and designing these structures and developing their applications have practical effects in chemistry and biology. We use a facile route based on interfacial polymerization to generate Turing-type polyamide membranes for water purification. Manipulation of shapes by control of reaction conditions enabled the creation of membranes with bubble or tube structures. These membranes exhibit excellent water-salt separation performance that surpasses the upper-bound line of traditional desalination membranes. Furthermore, we show the existence of high water permeability sites in the Turing structures, where water transport through the membranes is enhanced.

  17. Production of Actinium-225 via High Energy Proton Induced Spallation of Thorium-232

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, James T.; Nolen, Jerry; Vandergrift, George; Gomes, Itacil; Kroc, Tom; Horwitz, Phil; McAlister, Dan; Bowers, Del; Sullivan, Vivian; Greene, John

    2011-12-30

    The science of cancer research is currently expanding its use of alpha particle emitting radioisotopes. Coupled with the discovery and proliferation of molecular species that seek out and attach to tumors, new therapy and diagnostics are being developed to enhance the treatment of cancer and other diseases. This latest technology is commonly referred to as Alpha Immunotherapy (AIT). Actinium-225/Bismuth-213 is a parent/daughter alpha-emitting radioisotope pair that is highly sought after because of the potential for treating numerous diseases and its ability to be chemically compatible with many known and widely used carrier molecules (such as monoclonal antibodies and proteins/peptides). Unfortunately, the worldwide supply of actinium-225 is limited to about 1,000mCi annually and most of that is currently spoken for, thus limiting the ability of this radioisotope pair to enter into research and subsequently clinical trials. The route proposed herein utilizes high energy protons to produce actinium-225 via spallation of a thorium-232 target. As part of previous R and D efforts carried out at Argonne National Laboratory recently in support of the proposed US FRIB facility, it was shown that a very effective production mechanism for actinium-225 is spallation of thorium-232 by high energy proton beams. The base-line simulation for the production rate of actinium-225 by this reaction mechanism is 8E12 atoms per second at 200 MeV proton beam energy with 50 g/cm2 thorium target and 100 kW beam power. An irradiation of one actinium-225 half-life (10 days) produces {approx}100 Ci of actinium-225. For a given beam current the reaction cross section increases slightly with energy to about 400 MeV and then decreases slightly for beam energies in the several GeV regime. The object of this effort is to refine the simulations at proton beam energies of 400 MeV and above up to about 8 GeV. Once completed, the simulations will be experimentally verified using 400 MeV and 8 Ge

  18. Thorium fuel-cycle development through plutonium incineration by THORIMS-NES (Thorium Molten-Salt nuclear energy synergetics)

    International Nuclear Information System (INIS)

    Furukawa, K.; Furuhashi, A.; Chigrinov, S.E.

    1996-01-01

    Thorium fuel-cycle has benefit on not-only trans-U element reduction but also their incineration. The disadvantage of high gamma activity of fuel, which is useful for improving the resistance to nuclear proliferation and terrorism, can overcome by molten fluorides fuel, and practically by THORIMS-NES, symbiotically coupled with fission Molten-Salt Reactor (FUJI) and fissile-producing Accelerator Molten-Salt Breeder (AMSB). This will have wide excellent advantages in global application, and will be deployed by incinerating Pu and Producing 233 U. Some details of this strategy including time schedule are presented. 14 refs, 2 figs, 4 tabs

  19. Thorium utilization as a Pu-burner: proposal of Plutonium-Thorium Mixed Oxide (PT-MOX) Project

    International Nuclear Information System (INIS)

    Aizawa, Otohiko

    2000-01-01

    In this paper, a Pu-Th mixed oxide (PT-MOX) project is proposed for a thorium utilization and a plutonium burning. None of plutonium can be newly produced from PT-MOX fuel, and the plutonium mass of about 1 ton can be consumed with one reactor (total heavy metal assumed: 100 tons) for 1 year. In order to consume plutonium produced from usual Light Water Reactor, it should be better to operate one PT-MOX reactor for three to five Light Water Reactors. (author)

  20. Comparing Russian and Finnish standards of water purification

    OpenAIRE

    Maria, Pupkova

    2012-01-01

    The subject of this thesis is water purification. The first aim of this thesis is to consider different ways of water purification. The second aim is to compare Finnish and Russian standards of water purification. The third one is to show water purification methods on the pattern of Mikkeli water purification plan. Water purification methods of water intended for human consumption will be described.Combined tables will be done according to the quality requirement of drinking water of both,...