WO2009103974A1

WO2009103974A1 - Electrical power generating system comprising a radioactive substance

Info

Publication number: WO2009103974A1
Application number: PCT/GB2009/000450
Authority: WO
Inventors: Alexander Keith Bushell; Michael James Doggwiler
Original assignee: Permastar Ltd
Priority date: 2008-02-19
Filing date: 2009-02-19
Publication date: 2009-08-27
Also published as: GB0802969D0

Abstract

The present invention relates generally to electrical power generating systems and in particular to such systems which utilise the decay products and characteristics of radioactive substances such as photons from light emitted wave lengths and electrons which may be optimised using specific refraction and magnification techniques and converted into electrical power by specifically adapted photovoltaic cells and nanoparticles. An electrical power generating system comprising: at least one container which, in use, is sealed to the atmosphere to form an inner cavity; a layer of fluorescent material, in electromagnetic communication with the cavity; at least one radioactive substance within the inner cavity; and a plurality of photovoltaic cells positioned in the proximity of said at least one sealed container, whereby electrical power is generated by the plurality of photovoltaic cells.

Description

ELECTRICAL POWER GENERATING SYSTEM COMPRISING A RADIOACTIVE SUBSTANCE

Field of the Invention

The present invention relates generally to electrical power generating systems and in particular to such systems which utilise the decay products and characteristics of radioactive substances such as photons from light emitted wave lengths and electrons and convert these into electricity by specifically adapted photovoltaic cells.

Prior At

The use of radioactive material to drive photovoltaic cells is known in the art - see, for example, US Patent US 3,483,040.

International Patent Application WO-A-99/21232 and US Patent US 6,479,743 disclose nuclear (or nuclide) batteries which utilise this principle in small format in order to provide an electrical battery.

The use of this concept for capturing energy from nuclear waste is also known - for example, see US Patent 4,242,147, International Patent Application WO-A- 99/36967 and Japanese Patent Application JP 2003279691.

However, significant challenges exist in creating an economically viable electrical generating system based on the principle of driving photovoltaic cells through the use of radioactive material, in terms of achieving an appropriate cost efficiency of energy production.

Prior art systems required an entire system to be built, operated and maintained as a single unit - any failure of a component implicitly caused a failure of the whole system which is either impossible or extremely expensive to repair. The power-production efficiency of prior art systems is also very low.

It is an object of the present invention to provide an improved electrical power generating system.

It is a further object of the present invention to provide an electrical power generating system which may be easily built, operated and maintained, and is modular, in both size and output generation.

It is a further object of the present invention to provide an electrical power generating system which may be easily scaled in size, from a nano scale, that is in the form of nano- or micro-batteries - to reactors similar in scale to major power generation facilities.

It is a yet further object of the present invention to provide an electrical power generating system with improved electrical power production efficiency that are several orders of magnitude greater than prior art systems.

It is an even further object of the present invention to provide a source of electricity at micro and nano scales to devices that have been previously unable to operate at such scales because of the lack of appropriately scaled power generation systems.

Summary of the Invention

According to a first aspect of the present invention there is provided an electrical power generating system comprising at least one container which, in use, is sealed to the atmosphere to form an inner cavity; a layer of fluorescent material in electromagnetic communication with the cavity; at least one radioactive substance within the inner cavity and a plurality of photovoltaic cells positioned in the proximity of said at least one sealed container, whereby electrical power is generated by the plurality of photovoltaic cells. The layer of fluorescent material is in electromagnetic communication with the cavity so that both radioactive particles and radiated energy are able to interact the layer of fluorescent material. The term is intended to encompass line of sight, as well as through a container walls so that radiation may be directed to the layer of material.

Ideally a plurality of sealed containers is provided. These may be rod shaped, flat sheets or discs. The sealed containers may be arranged in a linear array, curved or circular form or, as sheets, in a cuboid or parallelepiped configuration.

Preferably each sealed container has at least part of its inner surface coated with a layer of fluorescent material.

In an alternative embodiment the action of a photovoltaic cell is performed by nanoparticles, capable of turning radioactive emissions, such as gamma radiation and beta particles into electricity. Such nanoparticles, commonly referred to as quantum dots, are capable of performing this directly as a result of quantum reactions. Alternatively nanoparticles may be arranged to generate electricity indirectly, by way of a photoelectric effect, by firstly producing a photo as a result of a nuclear and then converting the photo into electricity using a photovoltaic cell.

For the purposes of the present invention, use of nanoparticles for either direct or indirect conversion is hereinafter referred to as photovoltaic conversion and a device including nanoparticles for either direct or indirect conversion, is hereinafter referred to as photovoltaic cell.

Other desirable and advantageous embodiments of the invention are set out in the dependent claims.

The present invention thus provides a modular system which is easier to build, operate and maintain than prior art systems. The system of the current invention is simple to scale up and down in size in order to match a user's power requirements and the requirements of the application. In a preferred embodiment, the invention provides an apparatus for, and method of, tuning light output as a result of a radioactive interaction, to match an optimum waveband required by the photovoltaic cell. This improves the efficiency of energy conversion.

Further objectives and advantages of the invention will become apparent from a consideration of the description and drawings, which, by way of example, describe embodiments of the invention in which sealed tubes (or other containers) containing tritium, or other radioactive substances for example Pu235 or Pu239 or other radioactive substances. The sealed containers are mounted or inserted into a modular unit including a containment structure.

Brief description of the drawings

Figure 1: is a schematic perspective drawing of a first embodiment of a system according to the invention;

Figure 2: is a schematic perspective drawing of a plug-in unit of a first embodiment of a system according to the invention;

Figure 3: is a schematic perspective drawing of an alternative configuration of a plug-in unit of a first embodiment of a system according to the invention;

Figure 4: is a schematic perspective drawing of a second embodiment of a system according to the invention;

Figure 5: is a schematic perspective drawing of an alternative configuration of a plug-in unit for portable and micro modular applications of a first embodiment of a system according to the invention; Figure 6: is a schematic perspective drawing of a third embodiment of a system according to the invention;

Figure 7: is a schematic perspective drawing of an alternative configuration of the system where photovoltaic cells are raised during tilted towards the sun; and

Figure 8: is a schematic perspective drawing of an alternative configuration of the system where photovoltaic cells are nanoparticles, within nano batteries, embedded in a garment and used to power a device such as a life support devices.

Detailed Description of the Invention

In figure 1 a system rack (1) contains five plug-in units. Each plug-in unit consists of a container mounting frame (2) for carrying a plurality of radioactive-substance- containing phosphor coated tubes on which are mounted four photovoltaic cell mounting frames (4) for carrying photovoltaic cells.

The system is totally and uniquely scaleable from the nano scale, through micro and up to reactor sized installations.

There are a range of optimisation techniques and technologies that form part of the invention and are used to increase the efficiency of electricity generation to allow improved economy and increase the practicality of the invention to be used to power devices and generate electricity in an entire range of voltages, from nano to macro applications.

Where the radioactive substance is in fluid form, for example tritium gas, increasing the pressure of the gas within the containment structure can be used to concentrate the amount of emissions in a given volume and hence the there is a greater amount of energy that is absorbed per unit area of photovoltaic cells (nanoparticles) which is presented to the container to generate electricity. Accordingly a system for controlling this includes a compressor, a means for sensing pressure and a feedback controller.

Upon introduction of a displacement device- such as a closed tube or cylinder - within a cylindrical container, the fluid containing the radioactive substance, is forced closer to the outside surface of the containment structure and thus a greater amount of radioactive energy per unit volume, leaves the container and reaches the photovoltaic cells.

By adding a coating of a substance such as gallium nitride (GaN) and aluminium nitride (AIN) coatings, greater energy conversion is achieved.

The efficiency and output of the system is enhanced by the refraction, magnification and reflection of light sources. One example of optimising the output using this approach is to coat the container with a bubbled glass to magnify the light being emitted before it reaches the photovoltaic cells. The insertion of reflective materials, eg white or silver around a cylindrical insert, also improves efficiency by reflecting light out of the tube to maximise the incident light on the photovoltaic cells.

In addition to generating electricity from the photovoltaic cells using the photon energy from the light emitted by the substances it is also possible to generate electricity using the photovoltaic cells directly as a result of the impacting beta particles or electrons which penetrate the photovoltaic cells before losing their energy to generate electricity by beta-voltaic effects.

In addition to optimising the photovoltaic cells to the frequency of light emitted, the invention also optimises the cell design according to the requirements of the beta-voltaic power generation.

Each of the plug-in units is connected electrically to a wiring loom (not shown) which connects to a control electronics box (8) containing control circuitry for the system. The power control electronics and systems integration will vary according to the scale at which the invention is being applied.

Each of the plug-in units may be inserted and removed separately as indicated by the arrows (11 ) in figure 1.

Figure 2 shows one configuration of the plug-in units for the system shown in Figure 1. The plug-in unit consists of a container mounting frame (2) which contains several sealed tubes (6). Each sealed container is a tube of borosilicate glass and contains tritium gas, or tube materials and radioactive materials. The inner surface of each tube is coated with a fluorescent material which emits light when bombarded by the particles emitted by the tritium and is one element of the performance and efficiency optimisation of the invention.

Four photovoltaic cell mounting frames (4) are mounted on each container mounting frame (2). The photovoltaic cell mounting frames (4) are mounted using hinges such that they may be swung away (12) to give access to the sealed tubes (6) for maintenance/replacement purposes.

Mounted on each photovoltaic cell mounting frame (4) are arrays of photovoltaic cells (5). The photovoltaic cells are created using a number of techniques, for example by epitaxy, so that their molecular structure is such that they optimise the conversion of the specific frequencies of light emitted by the radioactive substance and by the beta particle decay process. In addition, the layering of crystals in the cells and the specific architecture are similarly optimised toot the light frequencies and particle types of the specific radioactive substance being used as fuel.

The cells may also be nanoparticles, also known as quantum dots, for operating the invention at nanometric scales to power nano-sensors in other applications such as 'intelligent' garments, in many fields of sensor technology and in space science applications. The nanoparticles are similarly created using a number of techniques to match precisely the outputs of the radioactive substances being used as fuel for the purpose of maximising the efficiency of electricity generation.

Figure 3 shows an alternative configuration of a plug-in unit which is the same as that in figure 2 except that, instead of the sealed tubes (6) of figure 2, the configuration of figure 3 has a flat container (7) in the form of a thick hollow plate. The thick hollow plate is made for example of borosilicate glass and may contain tritium, or another radioactive substance that emits light and other decay products. The inner surface of the thick hollow plate is coated with a fluorescent material similar to that described above that optimises the photon output reaching the photovoltaic cells.

Figure 4 shows an alternative embodiment of a macroscale reactor sized generator in which plug-in units with container mounting frames (2) can be withdrawn from a system rack (1) by pulling on a handle (9). The plug-in units are mounted on spring-loaded rollers (10) which make their withdrawal easier. As shown in figure 4, individual sealed tubes (6) may be removed and replaced with ease.

Maintenance of the system is deliberately designed to be simple and easy, particularly as operators will be handing potentially 'hot' radioactive materials. Maintenance personal may simply withdraw a plug-in unit and look along to check that all tubes (or other containers) are still emitting light. Part of the electronic circuitry contained in the electronics box (8) consists of a voltage meter which senses the output voltage of the unit. In operation, the voltage output of the system is continuously stabilised, due to the functionality of the sealed tubes and photovoltaic cells. Thus, if the voltage meter dips below the continuously stabilised level, then this indicates that maintenance personnel should inspect the tubes and photovoltaic cells for a fault. The 'reading' of the voltage meter may be automated and a simple warning lamp (not shown) may be made to illuminate when the voltage dips below the continuously stable level. The fluorescent coating is selected in order to emit a particular wavelength of light and is optimised to maximise the output of light energy. The particular wavelength is that which causes the particular photovoltaic cells in the system to operate at their most efficient. The configuration of the photovoltaic cells is also tuned such that they operate at their most efficient at the wavelength of light emitted by the radioactive substance used as fuel.

In certain installations, elastic material (e.g. white rubber) is placed at suitable places around the system, in order to give a degree of "shake-proofing" to the system, this is also used in macro and micro versions of the system. Other materials are used on the nano scale and in some instances the photovoltaic cells are grown around and on the surface of the containment structure with the radioactive substance within.

The system may be used as a component for a larger generation system consisting of a large number of the systems as shown in figure 6.

The system may be used as a singular component for a micro generation system as shown in figure 5. In such a configuration, the system may be engineered as a robust, sealed unit that is recyclable as a whole unit at the end of its useful life.

The nanometric scale version may have much closer integration of the components and may also be sealed to provide a continuous source of electricity for a long period of time, typically 15 to 20 years depending on the specific features of the invention. Such nano batteries could power vital sensors used in medicine or in any applications where a low continuous source of electricity is required over a long period without external intervention.

Alternatively, a unit of the size shown in figure 4 (appx. 2m x 2m x 2m) may be installed as a single installation. Such a unit produces a constant electrical output of appx 150W - 250W. This level of output may, for instance, provide constantly- on low level lighting in a medium-sized underground garage using white LEDs as light sources. An alternative embodiment of the invention shown in figure 7 would be to place the cells so that they can emerge from the containment structures during hours of sunlight and pivot to maximise the angle of incidence to the sun and optionally also follow the sun's track by use of a motor and tracking device.

This version of the invention allows the photovoltaic cells to be powered by the sun, which provides energy orders of magnitude greater than many of the radioactive substances, to maximise efficiency. Tilting the photovoltaic panels to the correct angle and powering the photovoltaic cells with a motor allows the cells to be at the optimum angle with the sun at all times.

The nanometric scale application can be embedded into a garment with many thousands of nano batteries used to power sensors and e.g. life support equipment attached to the garment. The wearer would be literally wearing a power plant and the ingoing power generation can be used in e.g. space environments or other hostile environments where conventional electricity sources cannot be used and sunlight driven PV cells will not receive energy from the sun.

For example, the tubes, or containment structures of the radioactive substance being used to fuel the device, can be in a number of configurations to optimise the performance of the invention by increasing the efficiency.

Further variation may be made to the invention, for example, by including a miniaturised version of the electricity generator system in a retro-fit battery or cell.

Such a battery or cell may be used to power, for example a mobile telephone, a portable personal computer, such as a laptop, notebook or hand held portable

(palm) computer. Batteries or cells including the electricity generator can be used in other devices, in particular digital devices, such as portable global positioning systems (GPS) navigation devices, clocks, watches, radios, television receivers, torches (flashlights), cameras, imagers, video and sound recorders, hand held amusement or entertainment systems, MP3 players, short range communication devices - such as Bluetooth (Trade Mark) enabled systems - or any other electrical device requiring a relatively constant, low power current supply, typically from say 100-200 milliwatts to a 3-4 Watts.

The battery or cell is ideally of relatively small volume - typically smaller than a few centimetres in length, width and height - and able to be received in the aforementioned devices. A particular advantage of the battery or cell is its lifespan, which may be for several years, or even tens of years, thereby removing the need for replaceable and expensive lithium hydride batteries.

Claims

1. An electrical power generating system comprising:

at least one container which, in use, is sealed to the atmosphere to form an inner cavity;

a layer of fluorescent material, in electromagnetic communication with the cavity;

at least one radioactive substance within the inner cavity; and

a plurality of photovoltaic cells positioned in the proximity of said at least one sealed container, whereby electrical power is generated by the plurality of photovoltaic cells.

2. An electrical power generating system according to claim 1 wherein a plurality of containers is provided.

3. An electrical power generating system according to claim 1 wherein the sealed containers are from the group comprising: rods, sheets and discs.

4. An electrical power generating system according to any preceding claim wherein the sealed containers are arranged in a linear array, curved or circular form, or as sheets, in a cuboid or parallelepiped configuration.

5. An electrical power generating system according to any preceding claim wherein at least part of an inner surface of a container is coated with a layer of fluorescent material.

6. An electrical power generating system according to any preceding claim wherein the photovoltaic cell includes nanoparticles, capable of turning radioactive emissions, such as gamma radiation and beta particles into electricity.

7. An electrical power generating system according to any preceding claim 1 wherein the sealed containers are sealed tubes of substantially circular cross-section.

8. An electrical power generating system according to any of the preceding claims further comprising at least one structure within the cavity which is operable to reduce the volume of the cavity.

9.. An electrical power generating system according to any of the preceding claims in which the pressure within the inner sealed cavities of the sealed containers is different from atmospheric pressure.

10. An electrical power generating system according to any of the preceding claims in which the sealed containers are made of glass or glass-ceramic.

11. An electrical power generating system according to any of the preceding claims in which the sealed containers are made of borosilicate glass.

12. An electrical power generating system according to any of the preceding claims in which the photovoltaic cells comprise amorphous silicon and are formed into a glass-laminated photovoltaic panel.

13. An electrical power generating system according to any of the preceding claims in which the fluorescent material is a preselected fluorescent which substantially emits a particular preselected wavelength of light such that at least some of the plurality of photovoltaic cells generate more electrical power than if said fluorescent material were to emit at least one different wavelength of light.

14. An electrical power generating system according to any of the preceding claims in which at least some of the plurality of photovoltaic cells are preselected photovoltaic cells which generate more electrical power at the particular wavelength of light substantially emitted by the fluorescent material than they would do if said fluorescent material were to emit at least one different wavelength of light.

15. An electrical power generating system according to any of the preceding claims in which the fluorescent material emits a particular wavelength of light at the plurality of photovoltaic cells operate at their most efficient level.

16. An electrical power generating system according to any of the preceding claims in which the plurality of photovoltaic cells operate at their most efficient at the wavelength of light emitted by the fluorescent material.

17. An electrical power generating system according to any of the preceding claims further comprising:

a system rack in which said plurality of container mounting frames are removably mounted in such a manner that at least one photovoltaic cell mounting frame is positioned between each container mounting frame and its neighbouring container mounting frame.

18. An electrical power generating system according to claim 17 in which at least some of the plurality of photovoltaic cell mounting frames comprise photovoltaic cells on each of two opposing sides of said photovoltaic cell mounting frame.

19. An electrical power generating system according to claim 17 in which at least one of said plurality of photovoltaic cell mounting frames is movably mounted on one of said plurality of container mounting frames.

20. An electrical power generating system according to claim 17 in which said at least one of said plurality of photovoltaic cell mounting frames is movably mounted with hinges on one of said plurality of container mounting frames.

21. An electric power generating system according to Claim 17, adapted for micro-generation, in which the sealed containers and photovoltaic cells are permanently encased in rugged material...

22. An electrical power generating system according to any of claims 17 to 21 in which:

- each photovoltaic cell mounting frame further comprises at least one first electrical connection means;

- each of the photovoltaic cells on a particular photovoltaic cell mounting frame are electrically connected with at least one of said first electrical connection means;

- the system rack further comprises a plurality of second electrical connection means which are configured so as to connect with said first electrical connection means; and

- each of said second electrical connection means is connected onto a wiring loom of the system rack.

23. An electrical power generating system according to claim 22 in which the first electrical connection means of a particular photovoltaic cell mounting frame connect(s) with second electrical connection means upon full insertion of said particular photovoltaic cell mounting frame into the system rack.

24. An electrical power generating system according to any of claims 2 to 23 in which at least some of the photovoltaic cells are in physical contact with at least some of the plurality of sealed containers.

25. An electrical power generating system according to any of the preceding claims further comprising a luminosity-increasing additive material within the inner cavity.

26. An electrical power generating system according to any of the preceding claims in which at least one said radioactive substance comprises an isotope of hydrogen in gaseous form.

27. An electrical power generating system according to any of the preceding claims further comprising:

- an electrical sensing means which senses an electrical quality (such as voltage, current or power) of the electrical output of the system; and

- a maintenance alert means which indicates a need for system maintenance if a voltage sensed by said voltage sensing means falls below a predetermined voltage.

28. An electrical power generating system according to any of the preceding claims in which said at least one radioactive substance derived from nuclear materials or the waste products of a nuclear power generation plant.

29. A magnification bubbled layer of glass or plastic, which magnifies the light intensity, this can also act as a substitute for the photovoltaic cell's external layer.

30. An electrical power generating system according to any of the preceding claims in which at least some of said plurality of photovoltaic cells are positioned such that they may also be exposed to natural sunlight.

31. An electrical power generating system according to any of the preceding claims in which at least some of said photovoltaic cells are movable into a position in which they may also be exposed to natural sunlight.

32. An electrical power generating system according to claim 31 in which at least some of said photovoltaic cells are automatically moved into and/or away from said position by a movement control system in dependence on a current level of power generated by the system.