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	Fission - Wikipedia, the free encyclopedia
		In physics, nuclear fission is a process where a large nucleus such as uranium is split into two smaller nuclei.
		In biology, binary fission refers to the process whereby a prokaryote reproduces by cell division.
		In anthropology, fission refers to the process whereby a nationstate divides and becomes multiple states (example: Yugoslavia).
	en.wikipedia.org /wiki/Fission (137 words)

	nuclear energy -> Nuclear Fission on Encyclopedia.com 2002 (Site not responding. Last check: 2007-11-05)
		The process of nuclear fission was discovered in 1938 by Otto Hahn and Fritz Strassmann and was explained in early 1939 by Lise Meitner and Otto Frisch.
		The average energy released by the fission of uranium-235 is 200 million electron volts, and that released by uranium-233 and plutonium-239 is comparable.
		Fission can also occur spontaneously, but the time required for a heavy nucleus to decay spontaneously by fission (10 million billion years in the case of uranium-238) is so long that induced fission by thermal neutrons is the only practical application of nuclear fission.
	www.encyclopedia.com /html/section/nuclener_nuclearfission.asp (964 words)

	Nuclear Fission
		If a massive nucleus like uranium-235 breaks apart (fissions), then there will be a net yield of energy because the sum of the masses of the fragments will be less than the mass of the uranium nucleus.
		The fission of U-235 in reactors is triggered by the absorption of a low energy neutron, often termed a "slow neutron" or a "thermal neutron".
		Other fissionable isotopes which can be induced to fission by slow neutrons are plutonium-239, uranium-233, and thorium-232.
	hyperphysics.phy-astr.gsu.edu /hbase/nucene/fission.html (592 words)

	Dating Exhibit
		Fission tracks are created at a constant rate throughout time so that from the number of tracks present it is possible to determine the amount of time that has past since the track accumulation began.
		Spontaneous fission is accomplished by causing the nucleus of one parent uranium atom to split in two with such a force that it leaves a trail (track) of damage on the crystal in a mineral.
		Fission is induced through controlled irradiation with thermal neutrons of Uranium 235 (0.7 x 10 9 half-life) in a nuclear reactor.
	www.mnsu.edu /emuseum/archaeology/dating/dat_fission.html (658 words)

	Nuclear Fission Energy
		The energy released in the fission process, which is primarily in the form of the kinetic energy of the fission fragments, heats the water.
		The water serves both as a neutron moderator (it slows down the fission neutrons to thermal energies), and as a heat transfer fluid.
		The smaller fission cross sections associated with the fast neutrons (as compared with thermal neutrons) leads to higher fuel concentrations in the core and higher power densities, which, in turn, create significant heat transfer problems.
	www.lbl.gov /abc/wallchart/chapters/14/1.html (1302 words)

	Prompt neutrons in fission (from nuclear fission) -- Encyclopædia Britannica
		Binary fission represents the major reproductive procedure of unicellular organisms, but it also occurs in the process of embryonic development and tissue growth and repair of higher plants...
		The fission fragments are highly unstable because of their abnormally large number of neutrons compared with protons; consequently they...
		The energy released by the fission or the fusion of nuclei, in the form of heat, light, or other radiation, is called nuclear...
	www.britannica.com /eb/article-48312?tocId=48312 (936 words)

	World Nuclear Association \| Education \| Some Physics of Uranium (Site not responding. Last check: 2007-11-05)
		Whether fission takes place, and indeed whether capture occurs at all, depends on the velocity of the passing neutron and on the particular heavy nucleus involved.
		It is nonetheless possible to use this so-called fast fission in a fast reactor whose design minimises the moderation of the high-energy neutrons produced in the fission process.
		Creation of the fission fragments is followed almost instantaneously by emission of a number of neutrons (typically 2 or 3, average 2.5), which enable the chain reaction to be sustained.
	www.world-nuclear.org /education/phys.htm (3832 words)

	Articles - Nuclear fission (Site not responding. Last check: 2007-11-05)
		Though fission is most often and most easily initiated by the absorption of a free neutron, it can also be induced by striking a fissionable nucleus with other particles.
		Fission in any element heavier than iron produces energy, and fission in any element lighter than iron requires energy.
		This situation (expected number of neutrons causing fission is one or more) is called criticality, and the configuration is called a critical mass (although strictly speaking the shape is as important a factor as the mass; see below).
	www.gaple.com /articles/Nuclear_fission?mySession=94bcab1e96000e5365c91a352b6d5585 (2737 words)

	Cycle Versus Cumulative Fission Matrix Algorithm
		At the end of each batch we calculate the batch K. Since contributions to the fission matrix are accumulated over batches, the batch eigenvalues are not independent in a statistical sense, and hence the batch averaged eigenvalue and the associated standard deviation are not computed.
		From this figure we notice that the batch eigenvalue of the cumulative fission matrix is far superior to the batch eigenvalue of the cycle fission matrix, as expected, whereas the batch averaged eigenvalue of the cycle fission matrix and the batch eigenvalue of the cumulative fission matrix show comparable accuracy.
		The batch eigenvalue of the cumulative fission matrix algorithm and the batch averaged eigenvalue of the cycle fission matrix algorithm provide comparable results for tightly coupled problems, where there is enough neutron communication between different regions.
	www.sdsc.edu /~majumdar/thesis/node22.html (985 words)

	Fission Chicken
		Yes, Fission Chicken is engaged in a perpetual battle against the forces of brain death...
		Fission Chicken arrives and is subjected to their weird weapons and their weird creatures.
		Among the many weird and powerful villians Fission Chicken has faced, the most sneaky and tenacious are probable the Vortoxians, a race of marketing experts from an alien planet who have replaced their original bodies with ones of plastic and metal...
	www.geocities.com /chickenofwrath (2455 words)

	fission.html (Site not responding. Last check: 2007-11-05)
		Fission occurs when the nucleus of an atom splits into smaller parts.
		Fission occurs when a neutron (emitted from another atom) smashes into the nucleus and is absorbed.
		However, in order for the nucleus to "absorb" the neutron it must be "slow moving." That is to say a fast moving neutron will not be absorbed by the nucleus and fission will not occur.
	sln.fi.edu /guide/wester/fission.html (221 words)

	Re: Why do neutrons have to be slow to cause fission?
		The probability of fission for a thermal neutron hitting a nucleus that will fission with capture of a thermal neutron is hundreds of times greater than that for fission induced by a fast neutron.
		The Binding Energy of a nucleus (the difference between the mass of A hydrogen atoms and N neutrons and the mass of the nuclide peaks at iron (Fe-56 is the nuclide with the highest binding energy--equivalently, the greatest difference in mass between 28 Hydrogen Atoms plus 28 Neutrons minus the mass of Fe-56.
		There are two other major effects that enter into why fission occurs: the first is the nuclear shell theory which shows that certain nuclei with "magic numbers" of protons or neutrons are especially stable (nuclear equivalents of inert gases; Z=50 and N=82 are important in fission).
	www.madsci.org /posts/archives/may99/926370823.Ph.r.html (624 words)

	Fission Powered Mechs (Site not responding. Last check: 2007-11-05)
		Fission plants are 50% heavier than fusion plants.
		While a fission plant can move a mech and provide power for its systems, it has a problem with the uneven power demands of energy weapons.
		To determine the maximum wt of the energy weapons that can be carried, divide the fission plants rating by 100 and round down any fractions to the next half ton.
	members.aol.com /Solarmech/fission.html (868 words)

	The Difficult Years: Fission Research, 1939 - 1945 (Site not responding. Last check: 2007-11-05)
		Nuclear fission involved the splitting of nuclei with the release of enormous amounts of energy.
		The frightening possibility that this German effort might succeed in providing Hitler with a nuclear weapon was one of the driving forces of the Manhattan Project in the United States, which produced the nuclear weapons dropped on Japan in August 1945.
		He made a lot of errors in his initial work on fission, and because of his sense of superiority, his lack of vision, and his theoretical-physics background, he never recognized his errors and never saw that the project could progress more efficiently.
	www.aip.org /history/heisenberg/p11.htm (1107 words)

	Nuclear Fission (Site not responding. Last check: 2007-11-05)
		CNN Cold War - The Atomic Age: From fission to fallout...
		How does nuclear fission differ from nuclear fusion?...
		The History of the Atomic Bomb - Nuclear Fission - Nuclear Fusion...
	www.scienceoxygen.com /phys/67.html (166 words)

	Fission and Fusion (Site not responding. Last check: 2007-11-05)
		The attraction of nuclear fission as a source of power can be understood by comparing this value with the 50 kJ/g released when natural gas is burned.
		The amount of fissionable material necessary for the chain reaction to sustain itself is called the critical mass.
		K. In a hydrogen bomb, a fission reaction produced by a small atomic bomb is used to heat the contents to the temperature required to initiate fusion.
	chemed.chem.purdue.edu /genchem/topicreview/bp/ch23/fission.html (1691 words)

	Nuclear Fission Rocket
		Drive Details Fission rockets are thermal rockets that function by heating a working fluid with the thermal output of a nuclear fission reactor.
		In the case of gaseous-core fission drives, the heat transfer is by radiation across a transparent, heat resistant ceramic containment vessel.
		Unfortunately the exhaust gas of all fission thermal rocket is highly radioactive due to passage through the nuclear core, and for this reason this engine has never been popular on biont-populated systems, and is even banned in many planetary systems.
	www.orionsarm.com /ships/fission.html (478 words)

	Search Results for fission - Encyclopædia Britannica
		The height and shape of the fission barrier are dependent on the particular nucleus being considered.
		Fission can be induced by exciting the nucleus to an energy equal to or greater than that of the...
		Nuclear fission is a complex process that involves the rearrangement of hundreds of nucleons in a single nucleus to produce two separate nuclei.
	www.britannica.com /search?miid=1209571&query=fission (584 words)

	Nuclear Fission: Basics \| Nuclear Fission \| Science \| atomicarchive.com
		When a nucleus fissions, it splits into several smaller fragments.
		These fragments, or fission products, are about equal to half the original mass.
		Fission can occur when a nucleus of a heavy atom captures a neutron, or it can happen spontaneously.
	www.atomicarchive.com /Fission/Fission1.shtml (106 words)

	Fission, Chain Reactions and the Atomic Bomb
		Curricular Fit: Physics 30 Unit 4: Nature of Matter; Concept: Nuclear fission and fusion are nature’s most powerful energy sources; STS Connections: evaluating, qualitatively the risks and benefits of using fission and/or fusion as commercial sources of energy…
		Atomic fission was discovered in the winter of 1938-1939.
		Fission is basically the splitting of an atomic nucleus into roughly equal parts.
	www.quasar.ualberta.ca /edse456/apt/vignettes/fission.htm (665 words)

	Fission, Fusion, Helium 3, Nuclear, Energy, Free Energy, Alternate Energy, Electrical, Electronic, Moray, Tesla, Bruce ...
		Although the term "fission" has been mainly used to denote the type of disintegration in which radioactive uranium and radioactive thorium produce heat energy for nuclear reactors, the artificial disintegration of isotopic lithium is also possible.
		In this "fusion" to "fission" reaction, from 7 grams of lithium and one of hydrogen to 8 grams of helium, approximately, there is a loss of 0.0181 gram, equivalent to 17.1 M.e.v., due to the Aston fraction of hydrogen and lithium being so much greater than that of helium.
		The bottom line is that the "fission" of isotopic lithium with either protons or deuterons, affords, weight for weight, more energy than any other possible nuclear change.
	www.nuenergy.org /alt/IsoLithium.htm (950 words)

	EUROPA - Research - Energy - - The Physics of Fission Reactors (Site not responding. Last check: 2007-11-05)
		The material (or fuel) that is generally used in a nuclear fission reactor is uranium metal or uranium dioxide.
		A fissile isotope (such as U-235) is capable of undergoing fission by thermal neutrons whereas a fertile isotope (such as U-238) is capable of absorbing neutrons to form a fissile material.
		The neutrons produced in a fission reaction could all go on to initiate other fission events thereby liberating more neutrons, and so on, establishing a chain reaction.
	europa.eu.int /comm/research/energy/fi/fi_bs/article_1174_en.htm (1128 words)

	fission-track dating -- Britannica Concise Encyclopedia - The online encyclopedia you can trust!
		The fission results in radiation damage, or fission tracks, that can be made visible by preferential leaching (removal of material by solution) of the host substance with a suitable chemical reagent; the leaching process allows the etched fission-track pits to be viewed and counted under a microscope.
		Thus, the ratio of naturally produced, spontaneous fission tracks to induced fission tracks is a measure of the age of the sample.
		The fission process results in the release of several hundred million electron volts of energy and produces a large amount of radiation damage before its energy is fully absorbed.
	www.britannica.com /ebc/article?eu=389810 (964 words)

	Fission Energy (Site not responding. Last check: 2007-11-05)
		The discovery of nuclear fission by bombarding uranium with neutrons did not reveal all the story.
		In the fission process, the fragments and neutrons move away at high speed carrying with them large amounts of kinetic energy.
		The neutrons released during the fission process are called fast neutrons because of their high speed.
	www.science.uwaterloo.ca /~cchieh/cact/nuctek/fissionenergy.html (379 words)

	Manhattan Project Description (Site not responding. Last check: 2007-11-05)
		The second major struggle in the project was being able to sustain a fission chain reaction, which gives the atomic bomb its power.
		Fission occurs when the central part of an atom, the nucleus, breaks up into two equal fragments.
		Figure 3 illustrates a fission chain reaction, and Figure 4 shows a close-up of what occurs during fission.
	www.me.utexas.edu /~uer/manhattan/project.html (1387 words)

	Fission
		The chain reaction exists because the average number of free neutrons in a fission is greater than 1.
		When a neutron is produced in fission it does not instantaneously hit another uranium nucleus.
		In order for enough fissions to occur to maintain the multiplying effect of the chain reaction, the uranium sample must be a certain minimum size.
	academic.brooklyn.cuny.edu /physics/sobel/Nucphys/fiss.html (968 words)

	UW NPL 1996 Sect 3.6 Quasi-fission with A < 20 projectiles (Site not responding. Last check: 2007-11-05)
		The precise mechanism by which this occurs is yet to be established but is believed to be associated with the large ground state deformation of actinide targets.
		After the Coulomb barrier is penetrated, a hot deformed system is produced with a distance between the center of masses of the two halves, slightly less than that for the fission saddle point of this system.
		Calculations of the percentage of fission due to quasi-fission as a function of beam energy relative to the fusion barrier.
	www.npl.washington.edu /npl/ar96/ch3_6.html (391 words)

	Nuclear Fission Links (Site not responding. Last check: 2007-11-05)
		The Atomkeller-Museum at Haigerloch Haigerloch was the location of the German Atomkeller, lab for the study of nuclear fission during World War II.
		ABCs of Nuclear Science A comprehensive introduction to nuclear science-- antimatter, beta rays, cosmic radiation, radioactivity, the difference between fission and fusion, and the structure of the nucleus, for starters.
		Nuclear Fission Simple explanation of nuclear fission in the framework of the history of the Universe.
	fueltrac.nacintl.com /Links/Nuclear-Fission.htm (393 words)

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