Need some help, 2nd Year project - nuclear power

High-level waste is the highly radioactive waste resulting from spent nuclear fuel, as well as the chemical processing of spent nuclear fuel and irradiated target assemblies. The radioactivity comes from fission fragments and their daughter products resulting from the fission of U235 in production reactors. Although radiation from short-lived fission products (fragments and their daughters) will decrease dramatically in the next hundred years, radiation risks associated with the long-lived products will remain high for thousands of years. In the initial decay period, most of the radioactivity is due to Cs137, Sr90, and their short-lived daughter products. Plutonium, americium, uranium, and their daughter products are the major contributors to long-term radioactivity.

The Hanford, Washington, site manages the largest volume of high-level waste, but the Savannah River site in South Carolina contains more total radioactivity. At Hanford, high-level waste alkaline liquid, salt cake, and sludge are stored in 149 single-shell and 28 double-shell underground tanks. Double-shell underground tanks are also used to store waste at the Savannah River site. Hanford waste is less radioactive than Savannah River waste because much of the radioactive Cs and Sr has been removed, the waste is older and has had more time to decay, and it has been mixed with less radioactive waste.

High level waste is the reult of a few, well defined processes. As such, stream compositions fall within a few, narrow concentration ranges

Transuranic (TRU) waste contains alpha-emitting transuranic elements with half-lives of greater than 20 years and a combined activity of 100 nanocuries per gram of waste. Because of the long half-lives of many TRU isotopes, TRU waste can remain radioactive for hundreds of thousands of years. Some common isotopes found in TRU are plutonium239, 240, 241, 238, and 242; americium241; and curium244. TRU waste from weapons production results from the fabrication of plutonium components, recycling of plutonium from scrap, retired weapons, and chemical separation of plutonium. Unlike high-level waste that results from a few specific processes with a narrow range of physical matrices and chemical characteristics, TRU waste exists in many forms with a spectrum of chemical properties.