Fertile materials Thorium Uranium

Over the last six decades, a significant amount of work has been done in this area of nuclear science and technology. In the present review, an attempt has been made to highlight the recent developments in this branch of science concerning the actinide elements with special reference to thorium, uranium, and plutonium, specific isotopes of which are being used as fissile/fertile materials. 

Although the HTGR is not being widely used cotmnercially, its high thermal efficiency, its ability to produce process heat at high temperatures, and its relatively efficient use of natural uranium resources when fed with thorium as fertile material give it potential future importance. 

Farkas, M.S., Storhok, V.W, Pardue, W.M., Smith, R.A., Veigel, N.D., Miller,N.E., Wright, T.R., Bames, R.H., Chubb, W., Lemmon, A. W., Berry, W.E., Rough, F.A, Fuel and Fertile Materials -Uranium Metal and Alloys - Plutonium - Thorium - Metal-Ceramic Fuels - Coated-Paiticle Fuel Materials - Uranium and Thorium Oxides - Uranium Carbides, Nitrides, Phosphides, Sulfides and Arsenides - Fuel-Water Reactions , Reactor Mater., 9(3), 151-165 (1966) (Assessment, Electr. Prop., Meehan. Prop., Phys. Prop., Transport Phenomena, 77)... 

In spite of these considerations, studies (5i) have shown that the use of the low-enrichment uranium cycle in the HTGR may be attractive under some conditions. Of greater importance, perhaps, are the results (53) showing that recycle operation of the HTGR reusing bred from the thorium fertile material and making use of plutonium instead of as a makeup fuel is an attractive possibility. 

Nuclear Thorium cannot fully replace uranium in pressurized water reactors. Actually, it may only be energy used to replace U as a fertile material, but cannot replace it completely. It must be used in... 

FBNR is capable to utilize many types and combinations of fissile and fertile materials, such as uranium, plutonium, or thorium fuel. For example, plutonium from dismantled nuclear weapons could be used as fuel in combination with uranium or thorium, which is an extremely... 

On chemical separation of the uranium from the irradiated thorium, the is, of course, removed along with the It does not itself represent a serious radiation hazard and, since it has a long half-life, the buildup of its daughter Th in the extracted uranium is relatively slow. Consequently, it is possible to avoid the need for heavy shielding and remote handling of the recycle U provided that the fabrication of the fresh fuel elements is done within a short time of the separation of the uranium from the irradiated fertile material. 

All reactors without fertile materials (uranium or thorium) at the same power level and capacity fac-... 

All reactors without fertile materials at the same power level and capacity factor destroy plutonium at the same rate. In addition, this rate is faster than the rate of any reactor containing fertile materials (uranium or thorium), because fertile materials produce more weapons materials. All plutonium isotopes release about the same amount of energy per fission (within 2%, and nearly independent of the incident neutron energy). Without fertile nuclides in the system, all of the fission energy comes from plutonium. Therefore, if the reactor is operated at a certain power level, the total amount of plutonium will decrease linearly in time. Thus, all reactors... 

Uranium-238 and thorium, the fertile materials, have been cmi-idi for use in converter or breeder reactor systems. The solubility ot ura . is such that satisfactory aciiieous solutions of uranium can be obtann d use in the conversion of to plutonium. Substantial eflorts lui C ci r made to de clop solutions of thorium which could lie used as a I a two-region lireeder reactor system. 

The variable processing charges arising from labor, materials, and other factors dependent on the throughput of fuel and fertile material are represented by Rqs. (10-1) and (10-2) for processing thorium-uranium mixtures and uranium-plutonium mixtures, respectively. 

FERTILE ISOTOPE. A fertile isotope or fertile material is a substance that is not itself fissionable by thermal neutrons but can be converted into fissfle material. This conversion is typically carried out by irradiation in a nuclear reactor. There are two basic fertile isotopes thorium-232 and uranium-238. When these fertile materials capture neutrons, they are converted into the fissile isotopes uranium-233 and plutonium-239, respectively. 

Uranium and Thorium in Phosphate. (72) These elements can be separated from a variety of phosphate-containing materials, e.g., fertilizers, bones, teeth, animal tissues, and wastes using this procedure. The sample is oxidized (if necessary), dissolved and placed in a nitrate or nitrate-perchlorate solution. To this solution, sufficient aluminum nitrate is added to complex the phosphate. This solution is then... 

Arsenazo HI was applied in the determination of thorium in biological materials [103,104], natural waters [34,105,106], fertilizers [107], glass [108], silicate minerals [2,10,27,55,109], niobium and tantalum minerals [110], uranium minerals [3,18], manganese ores [19], lanthanide compounds [26,44], zirconium minerals [111], titanium concentrates [111], ilmenite and rutile [112]. Thorium was determined in waters with the use of the FIA technique [106]. 

Pitchblende is one of the most fertile sources of radioactive material. Its composition varies widely, but it always contains an oxide of uranium, associated with oxides of other metals, especially copper, silver, and bismuth the Austrian mineral contains cobalt and nickel the American, samples contain no cobalt or nickel but are largely associated with iron pyrites and arsenic zinc, manganese, and the rare earths are frequently present, while occasionally calcium, barium, aluminium, zirconium, thorium, columbium, and tantalum are reported. Dissolved gases, especially nitrogen and helium, are present in small proportions. 

The NAS has requested that only reactor concepts that do not contain any uranium or thorium be examined. Eliminating from the reactor prevents the production of more Pu. Similarly, eliminating thorium from the reactor prevents the production of The main reason for not including fertile nuclides is to preclude the production of additional weapons materials. A plutonium-only based fuel provides the highest plutonium destruction rate. 

---