**Nanomedicine,
Volume I: Basic Capabilities**

**©
1999 Robert A. Freitas Jr. All Rights
Reserved.**

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

**6.2.5 Nuclear Energy
Storage**

By nanotechnological standards, the energy stored in atomic
nuclei is huge. For instance, the energy density of an un-ionized radioactive
atom of U^{235} is 1.5 x 10^{18} joules/m^{3}, counting
the kinetic energy of all fissile decay products in the total. Hydrogen that
undergoes fusion into helium actually provides a much poorer volumetric energy
storage density than for fission, ~4.4 x 10^{16} joules/m^{3}
(again assuming storage of fuel as molecules), largely due to the comparatively
high atomic number density of fissionable heavy metals. The highest practical
energy density would be achieved by storing some theorized form of matter-friendly
stabilized antimatter perhaps converted to a two-phase hypergolic (self-igniting)
fuel,^{565} up to a maximum of ~2
x 10^{21} joules/m^{3} (fuel only) for platinum/antiplatinum
annihilation. The difficulty, of course, is accessing this potential resource
in a controlled and well-shielded fashion (Section 6.3.7).

Last updated on 18 February 2003