A linear accelerator, preferably of the monochromatic type, accelerates electrons which are directed onto a high Z target such as tungsten to generate gamma rays about 9 MeV, which are directed onto the fuel material such as U-238 which results in the (y,f) reaction, thus releasing about 200 MeV. A reactor built according to this principle requiring an accelerator driven by 1 MW will develop about 20 MW of power. The reaction is not self-sustaining and stops when the beam is turned off. This accelerator driven reactor may be used to "burn-up" spent fuel from fission reactors, if simply operated at 10 MeV. The photo-fission results in typical spent fuel waste products such as Cs-137 and Sr-90 which undergo photodisintegration by the (y,n) reaction resulting in short lived or stable products. Chemical separations of the spent fuel isotopes is not necessary. Of course, more than one accelerator may be used to drive the reactor to higher power levels, and speed-up the burn-up process. The fact that the reaction is not self-sustaining is a safety feature allowing immediate shut-down in the event of a problem.
A betavoltaic battery is a nuclear battery that converts energy from beta particles released by a beta emitting radioactive source, such as tritium, into electrical power. The application of tritiated amorphous silicon as an intrinsic energy conversion semiconductor for betavoltaic devices is presented. Thin-film contact potential tritiated amorphous silicon cells have been built. These cells, called tritium batteries, have a specific power of 24 watts per kilogram, a full load operating life of 10 years, and an overall efficiency on the order of 25%. Cheap, long-life, high energy density, low power batteries.
The entrapment of tritium is particularly apt in this application as it is readily substituted for the hydrogen present in hydrogenated amorphous semiconductors with good intrinsic electronic properties. Radioisotopes other than tritium, may also be used as a source of energetic electrons as well as other forms of energetic nuclear radiation such as krypton-85 for example.
Tritiated amorphous films are mechanically stable, free of flaking or blistering, with good adherence to the substrate and may be simultaneously deposited onto both conducting and insulating substrates using a discharge in tritium plasma. The silicon layer sputtered in a tritium/argon ambient at temperatures below 300oC results in a tritiated amorphous silicon firlm with the tritium concentration being variable from 5 to 30% depending upon deposition conditions.
Experimenter Paul Brown provided us with the following patent and bibliographical references for the benefit of individuals investigating electric spacecraft propulsion. We have added resource material from the ESJ library.
Mechanical devices are often described which claim to produce a net directional thrust from motion confined within the device. Thus far, no such device is known to have accomplished this claim without some reaction force transfer (usually of a viscous or frictional nature) to the external environment. Paul Brown presents examples of arguments sometimes used to justify the mechanical production of net thrust.
Unpublished letter related to persecution of new energy inventors. 1 Nov 1991.