Current Events — HabitableZone

Current Events » in reply to re: re

re: re
gbaikie — (archived)

I would assume that if the normal half life is a certain time period, and then the same material breaks apart in one millionth of the normal time period, then the kinetic energy of the material has increased by one million.
How would you interpret that situation?

Basically the same way, but what percentage of the material has been transformed so it's 1/millionth of half-life. Without knowing this you can't quantify how energy is emitted from a spent rod. Therefore in context of how energy comes from spent rods, it doesn't provide an answer.

"In nature, uranium atoms exist as uranium-238 (99.275%), uranium-235 (0.711%), and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years"
http://en.wikipedia.org/wiki/Nuclear_fuel_cycle

Further down page:
"Uranium was the first element that was found to be fissile. Upon bombardment with slow neutrons, its uranium-235 isotope becomes a very short-lived uranium-236 isotope, which immediately divides into two smaller nuclei, releasing nuclear binding energy and more neutrons. If these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs and, if there is nothing to absorb some neutrons and slow the reaction, the reaction is explosive. As little as 15 lb (7 kg) of uranium-235 can be used to make an atomic bomb.[6] The first atomic bomb worked by this principle (nuclear fission)."

And:
"Plutonium-239 has a half-life of 24,110 years. The nuclear properties of plutonium-239, as well as the ability to produce large amounts of nearly pure plutonium-239, led to its use in nuclear weapons and nuclear power. The fissioning of an atom of uranium-235 in the reactor of a nuclear power plant produces two to three neutrons, and these neutrons can be absorbed by uranium-238 to produce plutonium-239 and other isotopes. Plutonium-239 can also absorb neutrons and fission along with the uranium-235. Plutonium fissions provide about one-third of the total energy produced in a typical commercial nuclear power plant. The use of plutonium-239 in power plants occurs without it ever being removed from the nuclear reactor fuel, i.e., it is fissioned in the same fuel rods in which it is produced."
http://en.wikipedia.org/wiki/Plutonium-239

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