Patent Number: 044366957
Section: summary

This invention pertains to a nuclear reactor system for producing useful thermal energy and valuable nuclear materials, such as plutonium, uranium enriched in U.sup.233, or tritium, by irradiating suitable target materials with neutrons produced in a large containing chamber by explosions or other neutron-producing bursts occurring seriatim. Useful thermal energy produced by the explosions is absorbed by substantial quantities of very lean molten sodium slurry, much of which is introduced into the chamber in a pattern substantially surrounding the centroidal nuclear explosion. Heat exchangers permit this energy to be extracted and used. In addition, desired materials are preferably precipitated from the slurry and processed for the fabrication of a large free-falling mass and two high velocity slugs which are introduced into the chamber and concur to produce a fission explosion near the center of the large containing chamber. In prior art system designs, it has been necessary to pay special attention to two important considerations. These are the positioning of adequate quantities of slurry in suitable locations around the explosion and the fine control of the concurrence of the masses and/or slugs producing the explosion or other burst. The proper positioning of slurry in the chamber becomes a more serious concern as the magnitude of the contained explosion and of the containing chamber are increased. This is shown by the following illustrative example: Assume a stream of liquid which enters a substantially evacuated chamber with a downward velocity of 3.0 meters/second has a cross-sectional area of 1.0 dm.sup.2 so that 30 liters of liquid enters the chamber each second. In the first second, the liquid falls about 7.9 meters; in the second second, it falls about 17.7 meters; and in the third second, it falls about 27.5 meters. In the third second, 30 liters of liquid will be distributed within a volume of about 275 liters (assuming no sideways scattering) so that the "destiny" of liquid is about 10.9% of what it was when it first entered the chamber. In my prior reactor designs, this decrease in stream density has been countered by the "bunching" of such stream-sprays. The stream-sprays are given both a downward velocity and a horizontal velocity toward the center-line of the chamber. Note that if the stream-sprays come from an area with a radius of 8 meters from the center-line and are "bunched" into an area which has a radius of 4 meters, the liquid density therein is increased by a factor of four. As the size of the chamber is increased because of larger contained explosions, the volume of the chamber increases as the cube of the diameter but the surface area increases but as the square of the diameter. The quantity of liquid from a single opening of fixed size that can be falling within the chamber increases as the square root of the diameter. Also the energy and equipment needed to pump the working fluid greater distances with larger chambers increases as the diameter of the chamber. It may be desirable to increase the flow rate of the slurry to introduce more fluid into the chamber in a shorter time. However, such an increase in velocity of the lean slurry working fluid causes a much greater increase in erosion of conduit surfaces while the slurry falling a greater distance will cause more erosion of the bottom portions of the larger chambers. In the practice of these contained explosion reactor systems wherein the working fluids are of slurries, erosion not only "wears out" the reactor system sooner but also causes build-up of undesirable materials worn from the conduit walls within the slurry and/or the precipitates from the slurry. It should also be noted that the eroded materials in the slurries act to cause a still more rapid rate of erosion. Thus, with more erosion, there is the need for both more frequent and more complex processing of the precipitates and of the sodium remaining which contains materials dissolved therein. It will be readily recognized that fine and precise control of concurring masses which are to produce a prescribed nuclear explosion, or other, less energetic neutron-producting burst, is vital to the successful operation of a reactor of the type disclosed herein. If the masses are improperly fabricated or the timing of their travelings are so incorrect that the resulting concurrence of the three masses results in an assembly which is not super-critical, there will be no energetic neutron-producing burst and the masses will fall to the bottom of the chamber. However, if the timing of their travelings is moderately off, there will be an energetic neutron-producing burst of less than desired magntiude but yet of sufficient magnitude to atomize the masses and to produce some useful thermal energy. Likewise, if the velocities of the concurring masses are lower than optimum, the desired explosion will be of lower magnitude than desired and there will be less production of energy and isotopes. With projectiles being fired to intercept a free-falling mass, the importance of this control consideration is further highlighted. Because of the higher projectile velocities required, a high rate of acceleration must be used for the projectiles. Also, the start and rate of acceleration must be precisely timed with respect to the earlier release of the free-falling mass. The reactor system of this invention deals with these and other concerns of prior art systems. As in the abovementioned U.S. Pat. application Ser. No. 40,849, the preferred embodiment of this invention utilizes a contained fission explosion with a lean sodium slurry as the working fluid. However, the present system is designed to be a breeder of plutonium instead of U.sup.233 enriched uranium. The reactor of this invention preferably produces about 3.times.10.sup.12 joules every 30 seconds. While the explosion is three times the magnitude of the prior application, the power produced is but doubled. To assure that sufficient quantities of the lean slurry surround the center of the chamber at the instant of explosion or burst, slurry is pumped to the top of the chamber and into large containers. At a prescribed moment before each explosion, a bottom holding means of such containers is removed with sufficient speed to not interfere with the free-fall of the liquid which falls in the form of column-globs of great size. By providing each column-glob with a sufficient cross-sectional area and preventing the containing bottom holding means from interfering with the liquid by being withdrawn faster than the free-liquid will fall, the effects of liquid viscosity, surface tension, and adhesion of liquid to containing walls is minimal. By using such column-globs in combination with "bunching" spray streams and fine sprays, more working fluid can be positioned nearer the contained nuclear explosion at the required instant in each cycle. Hence, a smaller containing chamber and less pumping power are needed. Precise control of the projected slugs of this invention is also accomplished. The slugs contain much UH.sub.3. By maintaining the slugs at cryogenic temperatures, this UH.sub.3 can be maintained in a ferromagnetic state. As a result, very fine control of the velocity of the slugs can be obtained as the slugs are being propelled into the chamber toward concurrence with the large mass by careful regulation of magnetic fields along the initial flight paths of the slugs. This enables the intensity of any neutron burst or explosion resulting from concurrence of the two slugs with the free-falling mass to be very precisely controlled as to time and location as well as magnitude. Thus, the large contained burst reactor system of this invention has a substantial advantage over prior art systems both in providing means for placing substantially greater quantities of working fluid in close proximity to the centroidal explosion and through a larger and more precise explosion or burst being obtainable as a result of the finer control provided for the concurring slugs. The reactor system of this invention provides a great technological contribution toward the development of massive fusion explosion systems, such as were disclosed in my application Ser. No. 40,849, by teaching a method by which much greater quantities of working fluid can be positioned in closer proximity to a centroidal nuclear explosion so that an explosion-containing chamber of less volume than previously required can be utilized. With a fusion explosion system for the breeding of U.sup.233 enriched uranium with an energy output of 10.sup.13 joules per explosion-cycle, the free-falling column-globs of very lean slurry can be used in order to avoid the need for much larger containing chamber or to avoid more complex and more expensive means of containing explosions in a less voluminous chamber. The use of massive column-globs in an explosion-containing chamber as disclosed in this invention is not limited to nuclear explosion reactor systems, nor is such use limited to the containment of explosions for such column-globs themselves can be a cause of a highly energetic, explosion-like effect. Specifically, a large chamber may be provided with a small opening in an upper portion through which a meteor-like mass can enter and collide with the column-globs which are released at a coordinated time for producing useful thermal energy and desired chemical reactions, such as is disclosed in my U.S. Pat. application Ser. No. 119,516 filed Feb. 7, 1980. Note that the kinetic energy of an object "falling" from near the moon has about 23 times the energy needed to " lift" it from the moon.