Production of thorium 228 starting from a natural thorium …
FIG. 3 shows the variation of elemental thorium concentration of an aqueous nitric solution that has been used for washing a floc obtained by the process of the invention ... the inventors having indeed found that cumulative coprecipitation results in an increase in the rate of coprecipitation yield and consequently makes it possible to reduce ...
Comparing the environmental impacts of uranium- and thorium …
The reference closed thorium-uranium-233 fuel cycle ... the cumulative occupational dose from monazite extraction is 8.0 person-mSv/MT Th (Haridasan et al., ... but that there is a lower mass of uranium in HLW to "dilute" the fission product concentration in terms of mass fractions). At later times, where uranium and plutonium …
Coal Combustion
the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and ... cumulative releases for the 100 years of coal combustion following 1937 are predicted to be:
Thorium: Crustal abundance, joint production, and …
... The world's total thorium sources are reported to be about 1,400,000 [5] to 5,307,800 tonnes [6]. According to Jorden et al. [7], an estimated total amount of …
POTENTIAL FOR HUMAN EXPOSURE
The relative abundances of 10 identified thorium species depended on the thorium:EDTA concentration ratio. At low thorium concentrations, the thorium-EDTA complex was considered to interact with sand surfaces, and transport depended on groundwater flow rate. But at higher thorium concentrations, plume flow was higher than expected.
Call Regarding a Client Matter
cumulative total of 400,000 kilograms of natural thorium/uranium contained as contaminants (in concentrations ranging from 0.05 percent to 1.0 percent by weight) in various rare earth compounds and mixtures." The cumulative total of 400,000 kg was in place well before the 2017 direct transfer of control.
Formerly Utilized Sites Remedial Action Program: Wayne
The cumulative dose to the population within an 80-km radius of the WISS that would result from radioactive materials present at the site would be indistinguishable from the dose that the same population would receive from naturally occurring radioactive sources. ... and thorium concentrations in surface water,more ...
Thorium Concentrations in the Environment: A …
The average thorium concentration in the Earth's crust is about 5.6 ppm (or 5.6 mg/kg). The concentration of thorium is higher in the upper part of the Earth's crust, reaching 10.5 ppm, while its average concentration in the lower layers is 1.2 ppm …
Thorium : Element and geochemistry | SpringerLink
Thorium occurs as a trace element in common rocks and rock-forming minerals, with concentrations in the range of a few pp b to a few tens of ppm ().Th 4+ has an ionic radius of ∼ 1 Å (similar to that of U 4+).This high charge and radius precludes the substitution of major ions in minerals by Th 4+.As a result, Th 4+ (and U 4+) is not accommodated in …
(PDF) Radiological risk from activity concentrations of …
The activity concentration of 226Ra, 232Th and 40K in samples were found to vary from of 16 ± 0.6 to 62 ± 3.2 Bq kg−1 with an average 30 ± 1.1 Bq kg−1, 24 ± 0.9 to 63 ± 1.3 Bq kg−1 with ...
Ultra-selective removal of thorium from rare earths by …
The effect of initial thorium concentration and temperature on the adsorption of thorium is shown in Fig. 3 c-3d. The adsorption of thorium by ASG-AP and ASG-NP both increased smoothly with the increasing initial concentration of Th(IV) and the maximum adsorption could reach 103.8 mg g −1 and 39.84 mg g −1, respectively. The increase in ...
Thorium Concentrations in Plants: A Review of World Data
The 232 Th concentrations in vegetables in regions of a normal thorium background range from 5.0 × 10 –5 to 8.4 × 10 –2 Bq/kg with a geometric mean value of 2.4 × 10 –3 Bq/kg (wet weight). In regions with a high thorium background (thorium mining area in Nigeria), this value is 3.7 × 10 –2 Bq/kg, which is significantly higher than ...
Synergistic extraction and separation of thorium …
The concentration of thorium is significantly reduced from 19.90 mg/L to 1.4 μg/L when the mixed Cextrant 230 and Cyanex 923 was adopted as extractants, while it …
Thorium
Properties and Dosimetry. The long-lived isotope 232 Th is the parent of a naturally occurring radioactive decay series. The thorium decay series can be considered in two steps: (1) the formation of 224 Ra by the successive decays from 232 Th, and (2) the decay of 224 Ra and its daughters to stable lead ().The isotope Ra (half-life, 3.62 days) is an …
Concentrating on thorium
The second was to accurately determine the concentration of thorium, which is usually present at very low concentrations. This is hardly surprising seeing as uranium-234 is a minor uranium isotope, accounting for just 0.0055% of raw uranium, and its half-life is so long, meaning only a fraction will have decayed to thorium-230.
Evaluation of homogeneity of radioactive waste forms
Normalized concentration distribution along the slices of the hydrated cement block, with W/C = 0.35; NaN03 (wt %) = 4, for (a) uranium and (b) thorium tracers. *(C =slice average; Q = standard deviation; C = full matrix average.) 213 The more successful tests free of binning are based on comparing the cumulative distribution function F(x ...
Assessment of concentration of radium, thorium, and
Thorium concentration was discovered to be maximum for crusher powder (Rohtak) with a value of 653.2 ± 9 Bq/kg and a minimum value of 23.3 ± 2 Bq/kg. Similarly, the potassium concentration in building material samples was discovered to have a maximum value of 1351 ± 8 Bq/kg and a minimum value of 304.2 ± 4 Bq/kg. The …
Release behavior and mechanism of uranium and thorium …
The variation of thorium concentration in the second and third cycles is not obvious, and the trend is relatively slow and stable. The leaching law of thorium is similar to uranium, and the concentration of thorium in the first cycle has obvious difference. ... The cumulative leaching amounts of thorium by pH = 5.0 column and pH = 6.0 column ...
Estimation of Inhaled Effective Doses of Uranium …
Uranium and thorium are two common natural radioactive elements with high concentrations in Earth's crust. The main aim of this study is to estimate the …
Analysis of Thorium Concentration Anomalies on the Lunar …
China's Chang'E‐5 mission has collected lunar samples from a young mare plain with elevated thorium contents in the northeastern Oceanus Procellarum of the Moon. In this study, we first established a … Expand
Some observations on the uranium and thorium
The dispersion of the thorium concentration is distinctly greater than that of uranium; ionic radii differences may be the cause. ... Uranium and thorium distributions in accessory zircon from granitic rocks 713 Cumulative frequency Fig. 2. Test for lognormality on probability paper. Lognormality is approximated over a considerable percentile ...
Uranium and thorium
Overview This page contains the latest trade data of Uranium and thorium.In N/A, Uranium and thorium were the France's N/A most traded product, with a total trade of N/A. Between 2021 and 2022 the exports of Uranium and thorium grew by 432%, from €20 to N/A. Trade in Uranium and thorium represent N/A of total France trade.. Exports In N/A the export …
Uranium, polonium and thorium in infant formulas (powder …
The highest activity concentration found in the food samples was due to 40 K being present in all types of food. Among the other radionuclides, high activity concentrations were found for 210 Pb in beans and salt, 210 Po in fish, 226 Ra and 228 Ra in nuts and seeds. The main food groups that contributed most to the effective dose, in …
Challenging the thorium-immobility paradigm
Thorium is primarily concentrated in highly evolved geologic systems, owing to its high charge/radius ratio, which inhibits incorporation into common rock-forming minerals. A consequence is the...
Thorium Concentrations in Terrestrial and Freshwater
Abstract A review of the data on thorium concentrations in the tissues of terrestrial and freshwater organisms is given. It is shown that the concentrations of 232Th vary widely in the tissues of both animals and fish, reflecting environmental thorium concentrations. The thorium concentrations in agricultural animal tissues range from …
Estimation of Inhaled Effective Doses of Uranium and Thorium …
In China, the atmospheric concentrations of uranium and thorium of an associated radioactive area and their PM sizes are rarely investigated. Thus, this study aims to estimate the effective dose of uranium and thorium inhaled by humans in the workplace and the surrounding area. ... The 50% cumulative frequency cutoff point was set in the …
On the determination of transportation, range and …
The point cumulative semi-variogram (PCSV) method application helps to identify the range, distribution and transport of radionuclide at each sampling station. ... In some areas, thorium has high concentrations of black sand layers on gold bed reefs (Buccianti et al. 2009; World Nuclear Association 2013). Thorium is an element with low ...
CHAPTER 5. POTENTIAL FOR HUMAN EXPOSURE …
Concentrations of thorium in air, food, and/or drinking water are normally very low and thorium-containing substances are not generally readily absorbed by the body. Wet …
Nature, Sources, Resources, and Production of Thorium
Thorium is a naturally occurring, slightly radioactive element. It is widely distributed in nature with an average concentration of 10.5 ppm Th in the upper earth's crust. In general, thorium occurs in relatively small number in Th-enriched minerals: thorite, thorianite, monazite, bastnaesite, and thorogummite. However, the main world resources …
Thorium Concentrations in the Environment: A Review of …
A review of the world data on the concentrations of thorium activity concentrations in soils, the atmosphere, surface waters, and bottom sediments is presented. It is shown that in the areas with normal radiation background the 232Th concentrations vary from 5 to 95 Bq/kg in the soil, from 1.0 × 10–5 to 1.0 × 10–2 Bq/L in …