Strontium-90 is a radioactive waste product from nuclear reactors. It has a half-life of 29 years. How many years will it take for a quantity of strontium-90 to decay to 1/16 of its original mass? It will take 29 years to decay to ½ its original mass; another 29 years to decay to ¼; another 29 years to ⅛; and another 29 years to 1/16.
29 + 29 + 29 + 29 = 116 years

a. You have 180 g of a radioactive substance. It has a half-life of 265 years. After 1,325 years, what mass remains?

Show your work.

product of nuclear fission. It is present in significant amounts in spent nuclear fuel, in radioactive waste from nuclear reactors, and in nuclear fallout from nuclear tests. For thermal neutron fission as in today's nuclear power plants, the fission product yield from uranium-235 is 5.7%, from uranium-233 6.6%, but from plutonium-239 only 2.0%.[6]

Nuclear waste

Strontium-90 is classified as high-level waste. Its 29-year half-life means that it can take hundreds of years to decay to negligible levels. Exposure to contaminated water and food may increase the risk of leukemia and bone cancer.[7]

In April 1943, Enrico Fermi suggested to Robert Oppenheimer the possibility of using the radioactive byproducts from enrichment to contaminate the German food supply. The background was fear that the German atomic bomb project was already at an advanced stage, and Fermi was also skeptical at the time that an atomic bomb could be developed quickly enough. Oppenheimer discussed the proposal with Edward Teller, who suggested the use of strontium-90. James Bryant Conant and Leslie R. Groves were also briefed, but Oppenheimer wanted to proceed with the plan only if enough food could be contaminated with the weapon to kill half a million people.[8]

Remediation

Algae has shown selectivity for strontium in studies, where most plants used in bioremediation have not shown selectivity between calcium and strontium, often becoming saturated with calcium, which is greater in quantity and also present in nuclear waste.[7]

Researchers have looked at the bioaccumulation of strontium by Scenedesmus spinosus (algae) in simulated wastewater. The study claims a highly selective biosorption capacity for strontium of S. spinosus, suggesting that it may be appropriate for use of nuclear wastewater.[9]

Explanation: Edited by Unkown the quick secret student organization.

geologic time scale (for gradpoint) =)