Nuclear waste plutonium

Nuclear power reactors have the following safety issues nuclear waste, plutonium buildup and radioactivity. Nuclear waste from the reactor fuel consists of uranium that has been formed into a usable metal alloy and provided as small pellets, rods, or plates. The fuel is encapsulated with a metal cladding, such as zircaloy, which adds mechanical strength and also prevents radioactive contamination. 

Plutonium (Pu) is an artificial element of atomic number 94 that has its main radioactive isotopes at 2 °Pu and Pu. The major sources of this element arise from the manufacture and detonation of nuclear weapons and from nuclear reactors. The fallout from detonations and discharges of nuclear waste are the major sources of plutonium contamination of the environment, where it is trapped in soils and plant or animal life. Since the contamination levels are generally very low, a sensitive technique is needed to estimate its concentration. However, not only the total amount can be estimated. Measurement of the isotope ratio provides information about its likely... 

Thorium, uranium, and plutonium are well known for their role as the basic fuels (or sources of fuel) for the release of nuclear energy (5). The importance of the remainder of the actinide group Hes at present, for the most part, in the realm of pure research, but a number of practical appHcations are also known (6). The actinides present a storage-life problem in nuclear waste disposal and consideration is being given to separation methods for their recovery prior to disposal (see Waste treati nt, hazardous waste Nuclear reactors, waste managet nt). 

Nuclear wastes are classified according to the level of radioactivity. Low level wastes (LLW) from reactors arise primarily from the cooling water, either because of leakage from fuel or activation of impurities by neutron absorption. Most LLW will be disposed of in near-surface faciHties at various locations around the United States. Mixed wastes are those having both a ha2ardous and a radioactive component. Transuranic (TRU) waste containing plutonium comes from chemical processes related to nuclear weapons production. These are to be placed in underground salt deposits in New Mexico (see... 

Nuclear Waste Reprocessing. Liquid waste remaining from processing of spent reactor fuel for military plutonium production is typically acidic and contains substantial transuranic residues. The cleanup of such waste in 1996 is a higher priority than military plutonium processing. Cleanup requires removal of long-Hved actinides from nitric or hydrochloric acid solutions. The transuranium extraction (Tmex) process has been developed for... 

A general conclusion from the review of the distribution of plutonium between different compartments of the ecosystem was that the enrichment of plutonium from water to food was fairly well compensated for by man s metabolic discrimination against plutonium. Therefore, under the conditions described above, it may be concluded that plutonium from a nuclear waste repository in deep granite bedrock is not likely to reach man in concentrations exceeding permissible levels. However, considering the uncertainties in the input equilibrium constants, the site-specific Kd-values and the very approximate transport equation, the effects of the decay products, etc. — as well as the crude assumptions in the above example — extensive research efforts are needed before the safety of a nuclear waste repository can be scientifically proven. 

The political problems with profound economic impact could include, for example, the significance of the continuing worldwide growth of nuclear power, with such issues as the use of Highly Enriched Uranium (HEU) and Plutonium obtained from tire dismantling of U.S. and former USSR nuclear weapons the urgency of nonproliferation the disposal of civilian and military nuclear waste nuclear power alternatives. 

While public understanding of nuclear issues may lack sophistication and is often based on inadequate or even misleading information, the public s assessments are not irrational. Having been told over many years that spent fuel is nuclear waste, it is only natural that the public should insist on its disposal. If and when effectively informed ofthe fact that spent fuel is not a waste but an energy resource, there is every reason to believe that the public will reject its deliberate burial and favor its storage under secure conditions, just as it now favors consuming, rather than immobilizing, surplus weapons plutonium. 

Proliferation concerns have been and continue to be the basic cause ofthe official US. opposition to reprocessing and plutonium recycle, and have thus led to the official U.S. categorization of spent fuel as nuclear waste which should be permanently buried in geologic repositories. 

Nuclear fuel recycling allows more efficient nuclear fuel usage and less buildup of nuclear waste. Nuclear power reactors are designed to minimize plutonium build up and much of the plutonium that is produced inside the reactor is used during an ordinary fuel cycle. 

Gephart, R.E., A Short History of Plutonium Production and Nuclear Waste Generation, Storage, and Release at the Hanford Site, PNNL-SA-32153, Pacific Northwest National Laboratory, Richland, WA, 1999. 

Neptunium-237 is obtained as a by-product of making plutonium from uranium isotopes in nuclear reactors. Significant amounts of this element may be recovered from plutonium plant nuclear wastes. Both the recovery and purification of neptunium can be carried out by various chemical processes, including precipitation, solvent extraction and ion exchange. 

UOP molecular sieves (UOP) has developed the lonsiv family of ion exchange resins for the extraction of radionuclides from wastewater. lonsiv TIE-96 is composed of a titanium-coated zeolite (Ti-zeolite) and is used to separate plutonium, strontium, and cesium from alkaline supernatant and sludge wash solutions. The technology was developed by Pacific Northwest Laboratory (PNL) for use at the West Valley, New York, nuclear waste facility. The technology is commercially available. 

Ewing, R. C., Weber, W. J. Lian, J. (2004) Pyrochlore (A2B2O7) A nuclear waste form for the immobilization of plutonium and minor actinides. Journal of Applied Physics, 95, 5949-5971. 

Weber, W. J., Ewing, R. C. et al. 1998. Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium. Journal of Materials Research, 13, 1434-1484. 

Buck, E. C., Finn, P. A. Bates, J. K. 2004. Electron energy-loss spectroscopy of anomalous plutonium behavior in nuclear waste materials. Micron, 35, 235-243. 

Hart, K. P., Vance, E. R. et al. 1998. Leaching behaviour of zirconolite-rich synroc used to immmobi-lise high-fired plutonium oxide. In McKinley, I. G. McCombie, C. (eds) Scientific Basis for Nuclear Waste Management XXI. Materials Research Society Symposium Proceedings, 506, 161-168. 

NOTE References pertaining to plutonium in nuclear reactors and nuclear wastes are listed at end of entry on Nuclear Power Technology. 

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