Patent Number: 046631151
Section: summary

This application relates to an apparatus for protecting personnel and the environment from emissions of harmful radiation, such as radioactive emissions emanating from radioactive waste. More particularly, it relates to such an apparatus which includes a shielding part or parts so located as to be in a path of the radiated emissions and to absorb such emissions, at least in part, so that the electrical potential of the shielding part will be changed, and electrically conductive means for connecting such shielding part with a sink through an electrical load so as to consume the electrical energy generated and so as to remove the electrical charge from the shielding part, thereby enabling such part better to absorb additional radiation, and helping to stabilize the material of such part and prevent potentially explosive buildup of energy therein. The invention also relates to processes for protecting personnel and the environment from radiation. For many years intensive efforts have been made to protect personnel and the environment from harmful radiations from various sources and in recent years extensive research has been performed in an effort to reduce the harmful effects of various radioactive wastes, especially mixed wastes, such as those from spent fuel rods used for power generation, and those known as "weapons wastes". Various treatments of such nuclear wastes that have been tried include calcining, gas diffusion, concentration, solidification, fusion and incorporation in vitreous matrices, synthetic organic polymers or inorganic sorbents. After concentration and "solidification" in a suitable matrix, as described above, such wastes are transported to disposal sites, such as salt domes, and are buried therein. Although such treatments and storage may seem to be comparatively safe, there is always the possibility that radiation and heat released by the decaying radioactive material will fracture the matrix, and earth movements and water flows could carry released radioactive materials away from the disposal site, to areas where they may be harmful to humans, animals, fish and the environment in general. The present invention provides a means for converting at least a portion of the harmful radiation from radioactive wastes (and from other sources of harmful radiated emissions) to environmentally acceptable,safe, and often useful form,and it does this at relatively low voltage and low temperature so that any danger of explosion is minimized. Thus, harmful radiation is converted to useful electrical power, although the object of this invention is to protect the environment, rather than to produce power. The removal of electrical energy from the radiation absorbing means of this invention promotes further absorption of such radiation and also improves the resistance of the absorbing means to deterioration by radiation. Utilization of pairs of electrically conductive absorber-converters in paths of the radiation, which absorbers are connected to a load to draw off electrical charges therefrom, is preferred, and the employment of pairs of such absorbers, connected to common conductors to carry electricity to the load,is a further preferred mode of the invention. In accordance with the present invention an apparatus for protecting organisms and the environment from harmful emissions of radiation from a source thereof by shielding said organisms and the environment from at least a portion of such emissions comprises a plurality of shielding parts located so as to be capable of absorbing radiation emissions from the source thereof, with one such part being located farther away from the source than the other and with the shielding parts both being in the path of the same emissions, so that an electrical potential difference between such shielding parts is established, due to different absorptions of radiation by them, and electrical conductors communicating with such shielding parts and transmitting such difference in potential to a means for consuming electric power located remote from the radioactive source. In preferred embodiments of the invention the shielding parts are of electrically conductive materials, such as metals of different atomic numbers, separated by an insulator, e.g., epoxy resin, ceramic, mica, glass, air and means are present to induce initial charging of the shield(s) and to produce the resulting electric current. Also, it is often preferable for the shielding members to be in roughly spherical form and for pluralities of pairs of such shielding members to be used so that radiation passing through the first set(s) of members may be absorbed by subsequent set(s). In a broader aspect of the invention an electrically conductive shield acts to collect energy from harmful radiation and discharges such energy through an electrical load. The invention also relates to various processes for protecting humans and the environment and for reducing radioactivity. The closest references known to applicant include U.S. Pat. Nos. 3,939,366 (Ato et al.) and 4,178,524 (Ritter) and an article in Chemical and Engineering News, Vol. 32, No. 7, at p. 592 (Feb. 15, 1954), all of which are references that were relied upon by the Patent Examiner during the prosecution of Ser. No. 933,529. The Ato et al. patent teaches the direct generation of electricity from radioactive materials by means of semiconductors. The Chemical and Engineering News article mentions a semiconductor crystal with an impurity in it to form a junction similar electrically to a junction in a junction transistor and mentions strontium-90 as a source of radiant energy. The Ritter patent is for a radioisotope photoelectric generator to produce electrical energy at a high voltage, e.g., 25,000 volts. Ritter intentionally builds up potential difference while in accordance with the present invention such build-up is prevented. Ritter specifies that his photon-producing radioactive source of energy must be a source of energy less than 1 million electron volts and Ritter teaches the use of pure isotopes, rather than mixtures of different radioactive materials, such as are found in nuclear wastes. A very significant distinction between Ritter and the present invention is in the fact that Ritter is attempting to produce electricity and the object of the present invention is to protect personnel and the environment from radioactive emissions. Ritter does not teach varying resistance to consume the energy of the emissions and his "load" may not be sufficient to handle a burst of energy. Ritter does not mention such protective function for his apparatus and the lead shielding of the Ritter apparatus, which has no part in the electrical functions thereof, is the means by which he prevents harmful radiation from the radioactive source from reaching any personnel and the environment. Certainly, the environment is not protected by Ritter's "battery" . Thus, it is seen that the present invention is novel, useful and unobvious from the "prior art" mentioned. It is not conceded that the Ritter patent is part of the prior art, in view of applicant's conception of the invention at a date prior to Sept. 1, 1976, the filing date of the Ritter et al. parent application Ser. No. 719,532, and applicant's claimed diligence until the filing of her grandparent application on Apr. 13, 1977 (papers deposited on Mar. 24, 1977).