WO2009134457A1

WO2009134457A1 - Solid state power converter

Info

Publication number: WO2009134457A1
Application number: PCT/US2009/002750
Authority: WO
Inventors: David Lee Fuson
Original assignee: David Lee Fuson
Priority date: 2008-05-02
Filing date: 2009-05-04
Publication date: 2009-11-05

Abstract

A power converter for producing electricity from naturally-occurring or man- made radioactive sources. The radioactive source causes the emission of photons by a photoluminescent material and the photons emitted by the photoluminescent material cause a photovoltaic cell to produce electricity.

Description

SOLID STATE POWER CONVERTER

The present invention relates to a solid state power converter. In more detail, the present invention relates to a method and apparatus for converting the energy output by a radioactive source to electricity using the principals of quantum mechanics and kinetic energy.

Photoluminescence is a process in which a substance absorbs electromagnetic radiation and then radiates photons. Quantum mechanically, this can be described as an excitation to a higher energy state and then a return to a lower energy state accompanied by the emission of a photon.

Experimental French physicist Edmund Becquerel discovered the photovoltaic effect in 1839. French physicist Antoine Henri Becquerel discovered the existence of radioactive materials in 1896.

The first functioning nuclear reactor was the Clinton Laboratories in 1943 as part of the Manhattan Project. Later, the Clinton Laboratories were renamed Oak Ridge National Laboratory.

Currently, the main methods of creating electricity using the nuclear reactors developed as a result of the commercialization of that work utilize a Radioisotope Thermoelectric Generator (RTG), which uses a thermocouple, temperature differentials, and by steam generation from heating water due to radioactive decay to turn an electric generator. Such installations are expensive, and therefore necessarily large enough in scale as to produce sufficient electricity to justify the expense of building such power generation facilities and linking them to the power distribution grid.

There is also a need for decentralized power generation as shown by the many alternatives available commercially for power generation, including solar cells, generators, windmills, and other so-called alternative energy sources. It is an object of the present invention to provide such an alternative electrical power source.

Another object of the present invention is to provide a source of electrical power that utilizes materials that are considered the waste, or by-products, of nuclear power generation. Another object of the present invention is to provide a method of disposing of nuclear waste.

Another object of the present invention is to provide an electrical power generator that is in the nature of a power converter in the sense that potential energy from naturally- occurring or man-made radioactive materials are used as a source for producing electricity.

Other objects, and the many advantages of the present invention, will be made clear to those skilled in the art in the following detailed description of the preferred embodiment(s) of the invention and the drawing(s) appended hereto. Those skilled in the art will recognize, however, that the embodiment(s) of the present invention that are described herein are only examples of specific embodiment(s), set out for the purpose of describing the making and using of the present invention, and that the embodiment(s) shown and/or described herein are not the only embodiment(s) of method performed in accordance with the teachings of the present invention.

The present invention meets the above-described objects by providing a solid state nuclear power converter using radiation from a radioactive source to bombard a photoluminescent material, causing the emission of photons from the material. Next, a photovoltaic cell in close proximity to the photoluminescent material absorbs the photons to produce electric current and voltage. The resultant electric power that is produced is direct current (DC) from the photovoltaic cell. A second effect occurs from decay of radioactive material from the vast amount of liberated neutrons that strike the photoluminescent material. These speeding neutrons possess a high kinetic energy and are suddenly stopped by the photoluminescent material, causing as burst of photons to be emitted that can be absorbed by the photovoltaic cell. .

Referring now to the figures, Fig. 1 is a partially schematic view of a solid state power converter constructed in accordance with the teachings of the present invention.

Referring now to Fig. 1, the power converter comprises a radioactive source 10, the photoluminescent material 12, and a photovoltaic cell 14. The radioactive source 10 can be any naturally-occurring or man-made radioactive material, including, for instance, the spent fuel rods of a nuclear reactor, the by-products of processes for enriching uranium or other nuclear fuel, high- or low-grade uranium ore, or any other material that produces enough radiation to cause the photoluminescent material to emit sufficient photons to be absorbed and converted to DC electricity by the photovoltaic cell at a rate that makes power conversion economically viable.

Certain materials will absorb electromagnetic radiation and/or kinetic energy from radioactive particle impacts and emission of photons characteristic and such materials are referred to herein as the photoluminescent material. The photoluminescent material that is suitable for use in the power converter of the present invention is any material that, after being struck by the by-products of atomic decay and/or electromagnetic radiation causes an atom or molecule to engage in the photoelectric effect and emit photons. Suitable materials include any material that luminesces, fluoresces, or phosphoresces, including zinc sulfide, strontium aluminate, and calcium fluoride.

After the photons are emitted by the photoluminescent material, the photons are absorbed by photovoltaic cell 14, completing the power conversion process. The photovoltaic cell 14 is any photovoltaic cell that is, for instance available commercially from any number of vendors and is sized so as to produce electricity at maximum efficiency from the photons produced by the photoluminescent material. Such cells are available from, for instance, Mitsubishi, Sharp, Kyocera Solar, BP Solar, and other known vendors.

In one embodiment, the photoluminescent material 12 is sandwiched between the radioactive source 10 and photovoltaic cell 14, but any arrangement in which photoluminescent material 12 is positioned in close enough proximity to radioactive material 10 that incident radiation from radioactive material 10 causes photoluminescent material 12 to emit photons and the photovoltaic cell 14 is positioned in close enough proximity to photoluminescent material 12 that incident photons produced by photoluminescent material 12 causes the photovoltaic cell 14 to produce electricity is contemplated by the apparatus of the present invention

In this manner, the low-level radioactive waste and/or spent fuel rods from, for instance, a nuclear power generator, can be utilized for generating electrical power in a system that needs little or no maintenance. The waste and/or fuel rods, rather than being an undesirable waste that is, for instance, stored in expensive, secure storage for long periods of time, is thereby allowed to emit radiation for long enough periods of time, while all the time it converts that energy to electrical power in accordance with the present invention, that the present invention effectively provides an economically- favorable method of disposing of nuclear waste.

To increase the power conversion efficiency of the power converter of the present invention, mirrors or mirrored surfaces are used to reflect photons created from the quantum effect of photoluminescent material 12 to increase the likelihood that said photons will strike the surface of photovoltaic cell 14 and be converted to electric voltage and current. Finally, the photoluminescent material itself can be a source of radioactive energy and radioactive particles by making the photoluminescent material itself radioactive due exposure to an alternate radioactive source or by the impregnation of radioactive material. In the event the photoluminescent material becomes radioactive or is impregnated with a radioactive source, as long as it does not have a major effect the efficiency of power conversion then the power converter can be used to consume the vast pool of radioactive waste material currently stored throughout the United States awaiting final disposal.

Three tests have been performed in accordance with the present invention. The first test used approximately 3.00 Krad/hr of Gamma radiation from a Lanthanum source and no electricity was detected from a solid state power converter constructed in accordance with the present invention comprised of a disc of photoluminescent material approximately 10 cm diameter positioned approximately three inches from the lanthanum source with the photovoltaic cell positioned approximately 1 mm from the photoluminescent material and wrapped in mirrored material to reflect photons. The second test used the same power converter and photovoltaic cell and a one megawatt reactor (30% U²³⁵) in a cold state that produced a large gamma flux with a small amount of neutrons at varying distances from the source (measured from the wall of the pool) as set out in Table 1, below, and the results are set out in Table 1. The third test used the same reactor and power converter in varying power levels from 1 Watt to 1 Megawatt (1 MW) and the results are set out in Table 2. Clearly the third test show that changing dosages of gamma radiation and of neutron flux produce measurable voltages of electricity. Power output from the solid state power converter changes in an almost direct relationship with increasing neutron flux (see Fission Detector Current Amps, Table 2, column 3). Additionally, the gamma radiation component is needed to slightly increase the output voltages from the disc {see Table 1). After examining Table 2 and at the end of the experiment, the power converter continued to output voltage.

Those skilled in the art who have the benefit of this disclosure will also recognize that certain changes can be made to the component parts of the power converter of the present invention without changing the manner in which those component parts function and/or interact to achieve their intended result. All such changes, and others that will be clear to those skilled in the art from this description of the preferred embodiment(s) of the invention, are intended to fall within the scope of the following, non-limiting claims.

Table 1: Measured distances and dosages from 1 MW Nuclear reactor in powered down state. Minimum results were detected.

Table 2: Reactor operating at different power levels. 1 Watt to 1 MW

Claims

WHAT IS CLAIMED IS:

1. A solid state power converter comprising: a radioactive source; a photoluminescent material positioned in close enough proximity to said radioactive source as to cause the emission of photons as a result of exposure to incident radiation; and a photovoltaic cell positioned in close enough proximity to said photoluminescent material that the photons emitted by said photoluminescent material cause the production of electricity.

2. The power converter of claim 1 wherein said photoluminescent material comprises zinc sulfide.

3. The power converter of claim 1 additionally comprising a mirrored surface for reflecting photons produced by the photoluminiscent material.