Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Politics : Politics for Pros- moderated -- Ignore unavailable to you. Want to Upgrade?

To: MichaelSkyy who wrote (211315)	7/9/2007 1:42:55 PM
From: Triffin	Read Replies (2) \| Respond to of 793915

WHy in the world aren't we doing this ??? In a phrase .. nuclear non-proliferation .. From peakoil.com Fission FAQ V1.5 .. "I am attempting to put together a Fission FAQ file so we do not have to keep regurgitating the same argument over and over. Please let me know of any mistakes I make and I will edit in corrections. It would also help if this were a Sticky topic and stays where people can find it right off the bat. First the math behind Fission. Fission is a process that takes place on a nucleus level where fundamental particles interact to rearrange the building blocks of chemical isotopes into new chemical isotopes. Because these processes take place inside the nucleus of chemical isotopes they are dubbed 'nuclear', however both Fission, where the Nucleus splits and Fusion where the Nucleus grows are Nuclear, they rearrange the building blocks to change a chemical from one isotope into another isotope. When a nucleus of any element heavier than Iron is fissioned and the fragments are larger than Iron the result is a release of energy. This is a result of the fact that Iron is at the peak of the binding curve of energy, the particles that make up the nuclease of Iron are packed as tightly together as physical laws allow nucleons to be in normal matter. While the difference in the binding energy between Iron and Hydrogen is the greatest difference on the curve, the difference between the Actinide elements and Iron is great enough to release copious amounts of energy. An atom of Uranium 235 has a binding energy of about 218.89 MeV, Iron Fe-58 has a binding energy of 505+-2 MeV. When a nucleus of U-233, U-235, Pu-239 or Pu-241 fissions the binding energy is expressed as kinetic energy as the fission fragments speed away from each other, because the fission can result in a large range of fragment isotopes and a variable number of neutrons the energy release is averaged over a spectrum of possible results. U-233 averages 197.9 MeV, U-235 averages 202.5 and Pu-239 averages 207.1 Plugging these averages into formulas give an energy yield as follows; For U-233 one gram fissioned yields 24.22654024 MWh(t) For U-235 one gram fissioned yields 24.78966346 MWh(t) For Pu-239 one gram fissioned yields 25.35278668 MWh(t) To convert Thermal MWh into Electric MWh the heat released has to go through some sort of conversion process, typically this involves boiling water and using the steam to drive a turbine which in turn spins a generator to produce electricity. Not all Fission plants operate by simply heating water and using steam, some of the more efficient reactor designs heat a gaseous fluid like Helium or Carbon Dioxide which is used to directly drive a gas turbine, then used to heat water into steam and drive a steam turbine. This double use of the heat yields a considerable improvement in energy efficiency. An average fission plant converting heat directly into steam is about 33% efficient, a gas cooled reactor is closer to 50% efficient. Assuming the average reactor world wide produces 1000 MWe and is 33% efficient at converting heat to electricity it will produce 3030 MWt by Fissioning 122 grams of U-235 or 119 grams of Pu-239 per hour of operation. When a fission reactor fueled with Uranium starts up for the first time all of the fission takes place in the U-235 in the fresh fuel, however as the reactor continues to run a small percentage of the Uranium 238 which makes up the bulk of the fresh fuel is converted into Pu-239. Each 12 to 18 months after the first start of the reactor the system is shut down for heavy maintenance and refueling. During the refueling cycle about one third of the used or 'spent' fuel is removed and placed in a large cooling pool for temporary storage. The remaining two thirds of the fuel is examined for damaged elements and rearranged in the core of the reactor where it is joined by a one third core of fresh fuel. When the reactor maintenance and refueling is completed and the reactor is started back up only the fresh fuel is pure Uranium, the remaining two thirds has a mix of Uranium, fission products, and Plutonium. After another 12 to 18 months the reactor again shuts down for heavy maintenance and refueling and again one third of the fuel is replaced with fresh fuel. From that point on until the reactor is decommissioned the core will be a mixture of one third fresh(first cycle), one third second cycle fuel and one third, third cycle fuel. The fresh fuel used in most reactors is all Uranium Oxide, the third cycle fuel has more Plutonium than U-235 undergoing fission in it. Many European reactors now use a Mixed Oxide fuel loading where 30% of the fuel elements contain recycled Plutonium instead of enriched Uranium. For these reactors when one third of the fuel is replaced 10% of the total fuel is replaced with MOX elements. Any standard light water reactor can use this much MOX fuel without any modification to the reactor itself, however because of the differences in the way that Plutonium fissions compared to Uranium if the MOX exceeds 50% of the total fuel loading the reactor must either be designed for MOX or modified to operate correctly with it. The MOX fuel currently being used in Europe is made by recycling ‘spent’ fuel which has been used in a reactor for three to five years to recover the Uranium and Plutonium in it. On average ‘spent’ fuel has 1% mixed Plutonium isotopes in it that can be chemically separated from the Uranium and fission waste and recycled as MOX fuel. Most of this recovered Plutonium is currently being mixed with depleted Uranium in a concentration of about 7% vs. 93% Uranium but several other mixtures are being explored as options for future fueling systems. In the USA and FSU each 34 tons of weapons grade Plutonium is being mixed in 5% vs. 95% Uranium MOX elements and is to be used as fuel for civilian fission power reactors. Two other mixtures under study are 10% vs. 90% for Plutonium recovered from ‘spent’ MOX fuel elements, and a mix of 1% Plutonium, 5% U-235, 94% U-238, both of which are intended to allow Plutonium to be recycled repeatedly in standard reactors until it is all consumed. A final fuel under study in South Korea is TMOX-RG which has a mixture of reactor grade Plutonium, depleted Uranium and Thorium. TMOX-RG has the benefit of consuming Plutonium while producing Uranium-233 and is designed to be used as a replacement fuel for standard reactors. " Triff ..