Patent Number: 041464290
Section: summary

BACKGROUND OF THE INVENTION The field of this invention relates to nuclear reactors, and more particularly to an emergency disposal system for an "out of control" nuclear reaction, this disposal system taking the form of a mass separation system which separates the larger nuclear mass into a plurality of smaller masses. Nuclear reactors contain a plurality of fissionable material in the form of a plurality of elongated rods. Surrounding each of these rods is a control rod assembly and the nuclear reaction is controled by movement of the control rods and exposure of the fissionable material in one rod to the fissionable material in another rod. The rate of reaction is directly dependent upon the size of the mass. The more mass of fissionable material exposed, the greater the rate of reaction. If perchance an excessive amount of mass becomes exposed, what occurs is termed a "core meltdown". A "core meltdown" is perhaps the most discussed and most feared phenomenon of all potentialities of nuclear reactors. This problem is especially of major concern since the use of nuclear reactors to produce electricity is becoming quite common. The fantastic heat generated by a molten core, estimated about six thousand degrees Farenheit, is sufficient to melt through virtually any material that might be placed in its path as it bores downward through the reactor vessel and all containments, eventually releasing at least a portion of its radioactive fission product inventory through the earth, or possibly through breaks in the containment sphere. At the present time, the use of reliable and practical methods of containing a large molten mass of fuel that would probably result from a meltdown do not exist. At the present time, there has not been a complete meltdown of a nuclear reactor core. However, in certain instances there have been partial meltdowns which have been stopped by currently employed safety structure within the nuclear reactor. Even the occurrence of a partial meltdown has been described as a bit worse then the maximum credible accident. There is a chance that a complete meltdown would result in the fissionable material being directly exposed to the atmosphere and the pollution that would occur as a result thereof would undoubtedly be overwhelming. SUMMARY OF THE INVENTION The subject matter of this invention relates to structure which is to be incorporated within the building foundation for a nuclear reactor. If a complete meltdown occurs within a nuclear reactor, the molten mass of high temperature fissionable material will move by gravity in a downward direction, consuming everything in its path. The structure of this invention is to route the molten mass of material into a plurality of separate paths and then to further separate the separate paths of nuclear mass into still smaller separate quantities of fissionable material. By the separating of the combined nuclear mass into a plurality of separate masses, the rate of reaction is significantly slowed and also the produced heat of reaction is slowed. The net result is to eliminate the hazard produced by the combined quantity of nuclear mass. The structure of this invention achieves the prior objective by locating a plurality of passageways within the building foundation of a nuclear reactor facility. The passageways are constructed so that the molten nuclear mass is caused to be conducted within a plurality of separate first passageways and each first passageway is connected to a plurality of separate second passageways. Each second passageway is connected to a plurality of third passageways and, if needed, each third passageway is connected to a plurality of fourth passageways. At the junction between different passageways there may be included a readily meltable material, such as lead or tin or oxides thereof. The function of this material is to slow the movement of the nuclear mass and permit such to be evenly distributed between the different passageways. Also, the combining of the meltable material with the fissionable material functions to disperse the material and further decrease the rate of reaction. At each junction, the cross-sectional area of the passage leading to the junction is to be approximately equal to the cross-sectional area of the combined passageways leading from the junction. The fourth passageways may terminate in an explosive charge with this explosive charge being located in a bed of sand. Upon the fissionable material reaching the explosive charge, the explosive charge will automatically ignite causing the fissionable material to be finely dispersed within the sand. This fine distribution of the diffusable material would decrease the rate of reaction to where it is no longer considered harmful.