Thorium-based fuels for nuclear reactors are being considered for use with current and future designs in both large and small-scale energy production. Thorium-232 is as abundant on Earth as lead, far more common than all isotopes of uranium, leading to its greatly reduced cost. Thorium itself offers a significantly greater neutron absorption cross-section than uranium at thermal energies, resul...

The rate of ejection of alpha-recoil thorium-234 into solution from the surface of zircon sand gives an alpha-recoil range of 550 angstroms. The alpha-recoil thorium-234 atoms ejected into the groundwater may supply excess uranium-234. In pelagic sediments, ejected alpha-recoil thorium-234 may contribute to the supply of mobile uranium-234 in the sedimentary column.

This report investigates the use of solvent-solvent extraction for the secondary concentration of lead and thorium. The extraction reagents investigated in this report are: For the lead extraction: diethlyammonium diethyldithiocarbamate (DDDC) For the thorium extraction: trioctylphosphinc oxide (TOPO) and di-(2-ethylhexyl)phosphoric add (HDEHP). For all of the extractions 2-octanone was used as...

The soil-mushroom transfer of thorium and uranium was analyzed in two ecologically similar but geographically separated Spanish ecosystems by means of the transfer factor, TF. Uranium TF values were in the range 0.043-0.49, and thorium TF values in the range 0.030-0.62. These values were similar to those of (90)Sr, (239+240)Pu, and (241)Am found previously in the same ecosystems. Given the low ...

Electrospray-mass spectrometry (ES-MS) has been used for the first time to study the hydrolysis of thorium. Hence, important discrepancies exist in the literature concerning the appearance of the first hydroxo complex. By studying thorium species as a function of pH, it was possible to observe the appearance of the first thorium hydroxo complexes at pH 1 as well as the other hydroxo complexes a...

Brazilian systematic investigations on the use of thorium fuel cycles in nuclear power reactors started in 1965. During the 60's and early 70's the work was mainly concentrated on the thorium utilization in heavy water reactors (HWRs). This work was performed in the framework of a cooperation agreement with the, French CEA. In the frame of the International Nuclear Fuel Cycle program, Brazil st...

Our previous studies on water cooled thorium breeder reactor based on matured pressurized water reactor (PWR) plant technology concluded that reduced moderated core by arranging fuel pins in a triangular tight lattice array and using heavy water as coolant is appropriate for achieving better breeding performance and higher burn-up simultaneously [1–6]. One optimum core that produces 3.5 GW ther...

An on-line solid-phase extraction method linked to inductively coupled mass spectrometry (ICP-MS) has been developed for the determination of low levels of uranium and thorium in environmental samples. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to an ICP-MS, allows the simultaneous determination of thorium and uranium in different types of en...

A selective method for the determination of thorium (IV) using an optical sensor is described. The sensing membrane is prepared by immobilization of thorin-methyltrioctylammonium ion pair on triacetylcellulose polymer. The sensor produced a linear response for thorium (IV) concentration in the range of 6.46 x 10(-6) to 9.91 x 10(-5)mol L(-1) with detection limit of 1.85 x 10(-6)mol L(-1). The r...