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Fission The process of using a neutron

First law of thermodynamics the energy of the universe is constant same as the law of conservation of energy. (9.1) Fission the process of using a neutron to split a heavy nucleus into two nuclei with smaller mass numbers. (21.6) Formal charge the charge assigned to an atom in a molecule or polyatomic ion derived from a specific set of rules. (13.12) Formation constant (stability constant) the equilibrium constant for each step of the formation of a complex ion by the addition of an individual ligand to a metal ion or complex ion in aqueous solution. (8.9)... [Pg.1102]

Fission the process of using a neutron to spiit a heavy nucieus into two nuciei with smaiier mass numbers. (19.6)... [Pg.1094]

First law of thermodynamics the energy of the universe is constant same as the law of conservation of energy. (9.1) Fission the process of using a neutron to split a heavy nucleus into two nuclei with smaller mass numbers. (20.6)... [Pg.1104]

When neutrons strike the nucleus of a large atom, they cause that nucleus to split apart into two roughly equal pieces known as fission products. In that process, additional neutrons and very large amounts of energy are also released. Only three isotopes are known to be fissionable, uranium-235, uranium-233, and plutonium-239. Of these, only the first, uranium-235, occurs naturally. Pluto-nium-239 is produced synthetically when nuclei of uranium-238 are struck by neutrons and transformed into plutonium. Since uranium-238 always occurs along with uranium-235 in a nuclear reactor, plutonium-239 is produced as a byproduct in all commercial reactors now in operation. As a result, it has become as important in the production of nuclear power as uranium-235. Uranium-233 can also be produced synthetically by the bombardment of thorium with neutrons. Thus far, however, this isotope has not been put to practical use in nuclear reactors. [Pg.597]

The physical property of greatest interest for hafnium is how it responds to neutrons. A neutron is a very small particle found in the nucleus (center) of an atom. Neutrons are used to make nuclear fission reactions occur. Nuclear fission reactions take place when a neutron strikes a large atom, such as an atom of uranium. The neutron makes the atom break apart. In the process, a large amount of energy is released. That energy can be converted to electricity. [Pg.235]

Scientists have now found more than 20 isotopes of neptunium. Neptunium was once a very rare element, but it can now be produced somewhat easily in a nuclear reactor. A nuclear reactor is a device in which nuclear fission reactions occur. Nuclear fission is the process of splitting atoms when neutrons collide with atoms of uranium or plutonium. These collisions produce new elements. Neptunium is used commercially only in specialized detection devices. [Pg.369]

In Germany in 1938, Otto Hahn and Fritz Strassmann, skeptical of claims by Enrico Fermi and Irene Johot-Curie that bombardment of uranium by neutrons produced new so-called transuranic elements (elements beyond uranium), repeated these experiments and chemically isolated a radioactive isotope of barium. Unable to interpret these findings, Hahn asked Lise Meitner, a physicist and former colleague, to propose an explanation for his observations. Meitner and her nephew, Otto Frisch, showed that it was possible for the uranium nucleus to be spfit into two smaller nuclei by the neutrons, a process that they termed fission. The discovery of nuclear fission eventually led to the development of nuclear weapons and, after World War II, the advent of nuclear power to generate electricity. Nuclear chemists were involved in the chemical purification of plutonium obtained from uranium targets that had been irradiated in reactors. They also developed chemical separation techniques to isolate radioactive isotopes for industrial and medical uses from the fission products wastes associated with plutonium production for weapons. Today, many of these same chemical separation techniques are being used by nuclear chemists to clean up radioactive wastes resulting from the fifty-year production of nuclear weapons and to treat wastes derived from the production of nuclear power. [Pg.867]

An atomic nucleus with a large number of component nucleons is a very complicated structure indeed. But in some situations an extraordinarily simple model of it will do for predictive and explanatory purposes. When we are dealing with many aspects of nuclear fission, it is adequate to treat the nucleus as if it were a blob of fluid. Indeed, only the way such a fluid would behave when set into oscillatory motion and as described by classical mechanics is needed to account for many aspects of the fission process. Just think of the blob of fluid as bounded by its surface, a surface that is characterized by tensional forces parallel to itself. Then think of the nucleus into which a neutron has just been injected to tri er the fission process, say, as such a liquid put into a higher energy state and forced to oscillate subject to the constraint of its own surface tension. Many of the important features of the fission process can be predicted and explained using this simple model. [Pg.246]

Abstract The chapter is devoted to the practical application of the fission process, mainly in nuclear reactors. After a historical discussion covering the natural reactors at Oklo and the first attempts to build artificial reactors, the fimdamental principles of chain reactions are discussed. In this context chain reactions with fast and thermal neutrons are covered as well as the process of neutron moderation. Criticality concepts (fission factor 77, criticality factor k) are discussed as well as reactor kinetics and the role of delayed neutrons. Examples of specific nuclear reactor types are presented briefly research reactors (TRIGA and ILL High Flux Reactor), and some reactor types used to drive nuclear power stations (pressurized water reactor [PWR], boiling water reactor [BWR], Reaktor Bolshoi Moshchnosti Kanalny [RBMK], fast breeder reactor [FBR]). The new concept of the accelerator-driven systems (ADS) is presented. The principle of fission weapons is outlined. Finally, the nuclear fuel cycle is briefly covered from mining, chemical isolation of the fuel and preparation of the fuel elements to reprocessing the spent fuel and conditioning for deposit in a final repository. [Pg.2617]

In 1938, Hahn, Strassman, and Meifner proved that they had fissioned the uranium atom using neutrons from an artificial source (a mixture of radium and beryllium). Scientists throughout the world used the values that were then known for the masses of the fission products versus that of the starting atom of uranium and concluded that a tremendous amount of energy is released in the fission process. The fissioning experiment was reproduced in about 100 different universities in the United States within the next year. The conversion of the mass lost in the fission process indicated that the fission of a uranium atom would release approximately 200 MeV (million electron volts). This is in sharp contrast to most chemical processes, such as combustion, which release only about 3-5 eV (electron volts) per combustion of a carbon or hydrogen atom. The ratio on an atom-to-atom basis is the order of 50,000,000 to 1. [Pg.864]


See other pages where Fission The process of using a neutron is mentioned: [Pg.422]    [Pg.6140]    [Pg.6139]    [Pg.319]    [Pg.477]    [Pg.863]    [Pg.341]    [Pg.20]    [Pg.13]    [Pg.18]    [Pg.201]    [Pg.631]    [Pg.155]    [Pg.949]    [Pg.62]    [Pg.18]    [Pg.67]    [Pg.256]    [Pg.809]    [Pg.580]    [Pg.510]    [Pg.348]    [Pg.152]    [Pg.2654]    [Pg.1305]    [Pg.724]    [Pg.771]    [Pg.829]    [Pg.52]    [Pg.138]    [Pg.12]    [Pg.157]    [Pg.364]    [Pg.319]   


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Fission The process of using a neutron to split

Fission neutron

Fission process

Neutron processing

Process of fission

Processes using

The Neutron

The a-process

Use Process

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