Uranium fuel cycle

The plutonium-uranium fuel cycle has particular advantages in fast spectrum... 

Thorium metal, 24 759-761 in alloys, 24 760-761 preparation of, 24 759-760 properties of, 24 760-761 reactions of, 24 761 Thorium nitrate, 24 757, 766 Thorium oxalates, 24 768-769 Thorium oxide, 21 491 Thorium oxides, 24 757, 761-762 Thorium oxyhalides, 24 762 Thorium perchlorate, 24 764 Thorium phosphates, 24 765-766 Thorium pnictides, 24 761 Thorium sulfate, 24 764 Thorium-uranium fuel cycle, 24 758-759 Thorocene, 24 772 Thorotrast, 24 775-776 3A zeolite. See Zeolite 3A Three-boiling beet sugar crystallization scheme, 23 463-465 Three-color photography, 19 233-234 3D models, advantages of, 19 520-521 3D physical design software, 19 519-521 3D QSAR models, 10 333. See also QSAR analysis... 

Fuel Recycle. Although the commercial CANDU reactors use the once-through natural uranium fuel cycle, it has been recognized for many years (22) that exceptional uranium utilization could be... 

EPA (1984) estimated that about 0.2 Ci of thorium-230 is annually emitted into the air from uranium mill facilities, coal-fired utilities and industrial boilers, phosphate rock processing and wet- process fertilizer production facilities, and other mineral extraction and processing facilities. About 0.084 Ci of thorium-234 from uranium fuel cycle facilities and 0.0003 Ci of thorium-232 from underground uranium mines are emitted into the atmosphere annually (EPA 1984). 

The use of the thorium-uranium fuel cycle in the HTGR provides improved core performance over the plutonium/uranium low-enrichment... 

Clegg, L. J Coady, J. R., "Radioactive Decay Properties of CANDU fuel Volume 1. The Natural Uranium Fuel Cycle," AECL-4436/1, Chalk River, Ontario, Canada, 1977. 

Environmental Standards for Uranium Fuel Cycle Standards for Normal Operation Annual dose not to exceed ... 

AEC. 1974. U.S. Atomic Energy Commission. Environmental survey of the uranium fuel cycle. USAEC Report WASH-1248. 

USNRC. 1981. United States Nuclear Regulatory Commission. Uranium fuel cycle environmental data. Federal Register 46 15154-15175. 

Figure 2. Overall refining process flow diagram with outline of complete uranium fuel cycle. (After Refs. 4, 7.)...

Separation of Long-Lived cc-Emitters from Highly Radioactive Solutions in the Thorium-Uranium Fuel Cycle... 

Figure 11.29 Radioactivity of individual radionuclides in HLW from the LWR uranium fuel cycle. Reprocessing, 150 days after reactor discharge enrichment, 3% U burnup, 30,000 MWd/MT heavy metal residence time, 1100 days 0.5% uranium and 0.5% plutonium remaining in HLW.

Fission energy can be obtained from uranium, using the uranium once-through option and the uranium-plutonium fuel cycle, and from thorium, by the thorium-uranium fuel cycle. Each fuel cycle offers a number of alternative routes with respect to reactor type, reprocessing, and waste handling. Although the uranium based cycles are described with special reference to light water reactors, the cycles also apply to the old uranium fueled gas cooled reactors. 

The advantage of the Th-U fuel cycle is that it increases nuclear energy resources considerably because thorium is about three times more abundant on earth than uranium and almost as widely distributed. In combination with the uranium fuel cycle it could more than double the lifetime of the uranium resources by running the reactors at a high conversion rate (-1.0) and recycling the fuel. Very rich thorium minerals are more common than rich uranium minerals. The presence of extensive thorium ores has motivated some countries (e.g. India) to develop the Th-U fuel cycle. 

The sole reason for using thorium in nuclear reactors is the fact that thorium ( Th) is not fissile, but can be converted to uranium-233 (fissile) via neutron capture. Uranium-233 is an isotope of uranium that does not occur in nature. When a thermal neutron is absorbed by this isotope, the number of neutrons produced is sufficiently larger than two, which permits breeding in a thermal nuclear reactor. No other fuel can be used for thermal breeding applications. It has the superior nuclear properties of the thorium fuel cycle when applied in thermal reactors that motivated the development of thorium-based fuels. The development of the uranium fuel cycle preceded that of thorium because of the natural occurrence of a fissile isotope in natural uranium, uranium-235, which was capable of sustaining a nuclear chain reaction. Once the utilization of uranium dioxide nuclear fuels had been established, development of the compound thorium dioxide logically followed. 

This regulation specifies both nvunerical dose criteria intended to protect the health and safety of the public and numerical radionuclide release criteria intended to protect the environment from the consequences of all normal uranium fuel cycle operations. Both limits are consistent with all of the selection bases and, therefore, are included as top-level regulatory criteria. 

Section 190.10(a) - Annual dose equivalent to a member of the general public from uranium fuel cycle operations (as defined in 190.02) ... 

The BN-350 is a fast breeder reactor located in Aktau, Kazakstan on the eastern shore of the Caspian Sea. The reactor began operation in 1972. It operated on an open uranium fuel cycle optimized to produce plutonium for the USSR weapons complex and generated steam for electricity, heat and seawater desalination. The reactor was in operation until April 1999 when decision for final shutdown had been taken by Government. In this report the operational experience is considered for the following equipment that directly contacts the liquid metal coolant The main circulation pumps of primary circuit ... 

Traditional demonstrated fuel cycle (DFC) view. For those already with access to or reserves of uranium, such as the United States, France, and Canada, the uranium fuel cycle is an already demonstrated fuel cycle (DFC) and is fine while uranium is cheap and assuredly available. 

We open with a concise introduction on the sources of uranium in nature and its main physical, chemical, and nuclear properties and then briefly discuss the chan-istry of uranium and its compounds with phasis on those that play an important role in uranium processing, namely, in the uranium fuel cycle. As we are concerned with the modem analytical chemistry of uranium, we present the foremost analytical techniques that are used nowadays to characterize uranium in its different forms. 

The main interest in the analysis of uranium in environmental samples is its effect as radioactive toxic heavy metal on the flora and fauna and assessment of the potential risk to human life directly or through the food chain. Natural uranium is present in practically all types of environmental samples—plants, soil, water bodies, and even air. In addition, anthropogenic activities related mainly to releases and discharges from the uranium fuel cycle may contaminate nearby areas, and that pollution may spread by wind and water action to considerable distances from the source. In order to assess the uranium content in the environment, representative samples need to be gathered (see Frame 3.2)—a task that is much more complicated than generally expected due to the variability of the sampled media. 

Generically, these eould be fast reactors with multiple recycle of all transuranics in the uranium fuel cycle as well as high conversion thermal spectrum reactors with multiple recycle of in the thorium fuel cycle. 

The fuel cycle options for the VBER-150 are the same as for the VBER-300 they include a once-through uranium fuel cycle (basic option), a uranium-thorium once-through fuel cycle to reduce specific plutonium production (Radkowsky Thorium Fuel — RTF — cycle), and a closed fuel cycle with MOX fuel, for details see [IV-1]. 

Specific consumption of natural uranium in a once-through uranium fuel cycle, t/GW(e)/year 487... 

The fuel element is the same type of pin-in-block design demonstrated in the HTTR and improved with a sleeveless fuel rod design. The low-enriched uranium fuel cycle has design characteristics of high (120 GW-d/t) bum-up and low power peaking factor for an extended (2-year) refuelling interval. 

Figure 17.2 Example of advanced uranium fuel cycle (Shropshire et al., 2008).

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