Answer to Question #13119 Submitted to "Ask the Experts"

Is it possible to generate electricity using radiation from contaminated waste sites? I realize that it may be difficult and maybe not worth the effort to safely install such a system, but is it theoretically possible?

The short answer to your question is "Yes, it is possible to generate electricity using radiation from contaminated waste sites." As you recognize, possibility and practicality may be quite different things, and such is the case here. It is true that ionizing radiation, by its nature, ionizes materials with which it interacts. That process produces free electrons and positively charged particles, which may, in some cases, be separated from each other via an applied electric field and yielding a current flow by way of the collected charge—i.e., electricity. For this to occur the free charges must not recombine or be captured by other material before they are separated in the electric field. This is practically impossible to accomplish in a situation in which the radioactive material is dispersed in solid or liquid material. Additionally, any currents realized under more idealized conditions, such as ionization of air in the vicinity of radioactive material, would not be very significant unless very large amounts of radioactivity were involved so as to yield very intense radiation fields, which would not be likely in a contaminated waste site.

The most common method for production of electricity from ionizing radiation interactions is when a thermoelectric material is heated when radiation interactions in the material is deposited through ionization and excitation. For this to be practical in such applications as generation of electricity to operate some devices in space and generation of electricity to operate warning lights on ocean buoys, very large amounts of radioactivity must be concentrated into rather small packages—e.g., perhaps 1,016 Bequerel (Bq) of beta-emitting ⁹⁰Sr in an ocean buoy or more than 1,015 Bq of alpha-emitting ²³⁸Pu in a space application. Even with these large amounts of radioactivity the typical electrical power outputs of such devices are on the order of only a few tens of watts.

Because of the generally dispersed nature of the radioactivity in contaminated waste sites it would be difficult and extremely expensive to accumulate the radioactivity into a suitable configuration for efficient heat generation and collection. Additionally, many contaminated sites contain radionuclides that emit gamma radiation as well as particulate radiation, and this may also be a mitigating factor against attempting to consolidate the radioactive material. The radionuclides favored for thermoelectric generation emit only particulate radiation, beta particles, or alpha particles, so as to avoid the significant hazards of protecting personnel who have to prepare, use, or spend time in the vicinity of the generators.

All things considered, I don't believe you would find any takers willing to undertake what you propose, despite its theoretical possibilities. Keep on thinking, though. Our waste problems on the planet are severe, probably nonradioactive more so than radioactive, and anything positive we can come up with is a plus!

George Chabot, PhD