thorium concentration average

Magnesium Thorium Alloy ca 1980s

20 Jan 2009 According to NUREG 1717 the average concentration of thorium in these alloys was about 1 7 There is a general trend away from the use of this material Its radioactive content can be high enough that special procedures are required when handling it and disposal can be expensive From 1973 to 1983 nbsp

Thorium Uranium and Zirconium Concentrations in Bauxite

Twenty nine samples of bauxites from different locations were ana lyzed for thorium and uranium by gamma ray spectrometric alpha count ing and wet chemical methods The thorium concentrations range from 5 0 to 131 ppm and average 48 9 ppm The uranium concentrations range from 2 7 to 26 7 ppm and average nbsp

Determination of thorium uranium and potassium elemental NCBI

From the measured gamma ray spectra elemental concentrations were determined for thorium range from 2 5 x 10 3 to 9 8 microg g 1 uranium from 8 1 x 10 4 to 3 2 microg g 1 and potassium from 1 3 x 10 4 to 1 9 The arithmetic mean values A M S D calculated from all samples are 1 2 1 7 microg nbsp

Guidance Note on the Disposal of Prepared Uranium Thorium

has a half life of 1 39 x 1010 years and is also an alpha emitter Uranium and thorium both occur widely at low concentrations in nature and measured levels of uranium in Irish soils range from less than 0 005 becquerels per gram Bq g to 0 543 Bq g with an average value of 0 039 Bq g For thorium the levels found in Irish nbsp

determination of uranium and thorium activity concentrations using

instrumental neutron activation analyses and for determination of thorium concentrations and delayed neutrons analysis for determination of uranium The mean specific activity for 238U and 232Th was higher in Cumuruxatiba than in others locations studied Alcobaça and Caraíva also presented high values The

uranium and thorium in selected suites of igneous rocks The

Uranium has been determined by the fiuorimetric method of Grimaldi and others 1952 adapted to lower concentrations of uranium The method yields results repro ducible and probably accurate to i 10 1These data are the averages of individual Tll U ratios not the ratio of the average thorium and uranium contents

Determination of thorium uranium and Semantic Scholar

gamma radioactivity for a counting time of 18 hours each From the measured γ ray spectra elemental concentrations were determined for thorium range from 2 5×10 3 to 9 8 μg g 1 uranium from 8 1×10 4 to 3 2 μg g 1 and potassium from 1 3×10 4 to 1 9 The arithmetic mean values A M ± S D calculated nbsp

Determination of uranium thorium and potassium activity

29 Jun 2007 The samples have been analysed by using gamma ray spectrometry From the measured gamma ray spectra activity concentrations are determined for 238U 232Th and 40K The mean activity concentration for 238U 232Th and 40K was found to be in the range 19 ± 1 4 to 38 7 ± 3 14 3 ± 0 8 to 35 ± 3 2 nbsp

Natural Radioactivity and Radiation Evaluation of Guidelines for

Typical concentrations in the more prevalent types of rock and average concentrations in the earth 39 s crust and in soil are listed in table 2 6 In the common rock types the uranium concentrations range from 0 5 to 4 7 ppm corresponding to activity concentrations for 238U of 7 60 Bq kg 0 2 1 6 pCi g The overall effect of soil nbsp

67 5 POTENTIAL FOR HUMAN EXPOSURE 5 1 OVERVIEW

1981 The average population weighted concentrations of thorium 232 and thorium 230 in United States community water supplies derived both from surface and groundwater were less than 0 01 pCi L and less than 0 04 pCi L respectively Cothern 1987 Cothern et al 1986 The maximum concentration of thorium 232 nbsp

1 GEOLOGY AND MINERALOGY OF THORIUM I2M Associates

Thorium is the 38th most abundant element in the crust of the earth averaging about 6 ppm with the Th U ratio about 3 It is relatively depleted in mafic rocks basalts where the concentration averages about 1 ppm although alkalic varieties high Na and K relative to Ca range up to 5 ppm Outstanding enrichments are nbsp

Facts About Thorium Live Science

28 Feb 2017 Higher concentrations of thorium are typically found in minerals such as thorite thorianite monazite allanite and zircon according to Los Alamos National Laboratory The most stable isotope of thorium Th 232 has a half life of 14 billion years according to the EPA According to Los Alamos thorium is nbsp

Thorium Deposits of the United States USGS Publications

thorium to REE concentrations in the veins averages around 1 1 Staatz 1972a reported the REE analyses of 31 vein samples which showed total REE oxide contents ranging from 0 073 to 2 20 percent with an average value of 0 428 percent very similar to the average thorium oxide content of 0 43 percent found in the nbsp

Thorium concentration and the activity ratios230Th 232Th and228Th

20 Mar 1970 Thorium isotopes were analyzed by α ray spectrometry after separating them with an anion exchange resin The average content of thorium 232Th of 2 2×10−9 g l was obtained in the open Pacific waters The ratio of230Th 232Th is in accord with that of the top layer of the sediment in the same area

Uranium and Thorium Distribution in Soils and Weathered Bedrock

16 Tables Table 1 Average values of uranium and thorium and the thorium uranium ratio for each profile 10 mentary bedrock in south Texas indicates that uranium and thorium are leached from the surface layers and deposited deeper concentration is apparent If the deposition of the ions was solely by adsorption nbsp

Estimating terrestrial uranium and thorium by antineutrino flux

8 Jan 2008 Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations This article describes the methods and criteria to experimentally determine average concentrations of uranium and thorium in the continental crust and in the mantle by using nbsp

The thorium uranium and zirconium concentrations in bauxites and

are generally much greater than the average for crustal rocks but also that there is a definite relationship be¬ tween the thorium and uranium contents of a bauxite and its parent rock type For the 29 bauxite samples the thorium concentration ranges from 5 0 to 130 7 p p m and has an average value of 48 9 p p m the nbsp

Naturally Occurring Radioactive Materials NORM World Nuclear

Exposure to naturally occurring radiation is responsible for the majority of an average person 39 s yearly radiation dose see also Nuclear Radiation and Health The concentration of uranium and thorium in bottom and flyash can be up to ten times greater than for the burnt coal while other radionuclides such as Pb 210 and nbsp

Thorium uranium and zirconium concentrations in ResearchGate

Twenty nine samples of bauxites from different locations were analyzed for thorium and uranium by gamma ray spectrometric alpha counting and wet chemical methods The thorium concentrations range from 5 0 to 131 ppm and average 48 9 ppm The uranium concentrations range from 2 7 to 26 7 ppm and average 11 4 nbsp

Occurrence of thorium Wikipedia

Thorium is found in small amounts in most rocks and soils it is three times more abundant than tin in the Earth 39 s crust and is about as common as lead Soil commonly contains an average of around 6 parts per million ppm of thorium Thorium occurs in several minerals including thorite ThSiO4 thorianite ThO2 UO2 nbsp

uranium and thorium bearing ores IRPA

extensive deposits are found with concentrations hundreds of times the average concentration Both uranium and thorium are naturally occurring radioactive materials and in nature are comprised of several isotopes The parent radionuclides U 238 U 235 and Th 232 are primordial radionuclides with half lives of 4 500 nbsp

Uranium 238 and thorium 232 series concentrations in soil radon

On the other hand taking into account that uranium and thorium are always present in soil their gamma radiation causes external exposures with the consequent absorbed doses Radon gas accumulates in indoor air The average dose that many populations receive from inhalation of radon is half that from all natural nbsp

Concentration and activity ratio of thorium isotopes in surface soil

28 Jul 2014 Thorium concentration in the surface soil samples from Lambapur Peddagattu and Seripally area are given in Table 1 Thorium concentration in the study area is varying from 15 ± 3 mg kg to 132 ± 15 mg kg with a mean of 68 ± 9 mg kg A wide variation in concentration of thorium in localized soil has nbsp

Thorium World Nuclear Association

In nuclear fuel fission gas release is much lower than in UO2 The most common source of thorium is the rare earth phosphate mineral monazite which contains up to about 12 thorium phosphate but 6 7 on average Monazite is found in igneous and other rocks but the richest concentrations are in placer deposits nbsp

Factors Controlling Low Uranium and Thorium Concentrations in the

24 Feb 2014 The average uranium and thorium concentrations of ÇBS 1 83 2 62 ppm are much lower than averages of UC NASK and PAAS uranium 2 70 2 66 3 10 ppm thorium 8 50 12 30 14 60 ppm Low uranium contents in comparison to those of similar lacustrine environments might be attributed to that waters nbsp

Thorium Uranium and Potassium Concentrations in CiteSeerX

The concentrations of thorium uranium and potassium have been de termined in the granites and gneisses of the Rum Jungle Complex The arithmetic means of all the rocks analyzed are 10 3 ppm U and 45 7 ppm Th This is more than twice the average concentrations of these elements in granites of similar major nbsp