E5 Energy Density of Nuclear Fuel

Topic

The amount of energy that can be extracted from a given mass of nuclear fuel is vastly greater than that of any conventional fuel of equal mass: the complete fission of a small quantity of uranium-235 releases energy on the order of millions of times greater than that released by the same mass of coal undergoing chemical combustion.

This difference of several orders of magnitude is not an accidental quirk but a direct reflection of the energy's source in each case: chemical combustion releases energy stored in the outer electron bonds of atoms, whereas the nuclear fission process—described in the first model of this catalog—releases energy stored in the force holding the nucleus itself together, an interaction far more intense than any chemical bond.

This extreme energy density means that the physical quantity of fuel requiring handling, transport, and storage is orders of magnitude smaller than what a conventional thermal power plant of equivalent output would require, and the volume of waste per unit of energy produced is correspondingly low in mass; however, unlike the ash from a coal plant, this waste remains radioactive for very long periods, introducing handling considerations entirely different from those associated with conventional fuel.

Thus, this module—which begins by comparing the energy yield of equal masses of two fuels—concludes by showing that this same difference in the physical origin of the energy (electron bonds versus nuclear force) explains both the practical advantage of handling far less fuel and the practical disadvantage of having to manage waste that remains radioactive long after use.

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