Patent Number: 043449115
Section: claims

1. A method for protecting the inner wall of an inertial confinement fusion chamber from damage by X-rays, neutrons, and debris generated by the implosion of fusion fuel targets in the chamber, comprising the steps of: forming the inner wall of the chamber so as to include an upright cylindrical section, forming an annulus about the exterior of substantially the entire upright cylindrical section of the inner wall, forming at least one annular opening adjacent an upper portion of the upright cylindrical section of the inner wall and in open communication with the annulus, forming a flowing wall of selected material in liquid form which flows along an inner wall surface of substantially the entire upright cylindrical section of the fusion chamber by directing the material through the annulus and through the at least one annular opening in the inner wall, recirculating at least a portion of the material from a lower portion of the fusion chamber upwardly through the annulus and inwardly through the at least one annular opening so as to produce a waterfall effect forming the flowing wall and to maintain a continuous flowing wall which substantially prevents generated X-rays, neutrons and debris from contacting the wall surface of the fusion chamber, forming a second annulus about the exterior of an upper section of the fusion chamber above the upright cylindrical section thereof and in open communication with the first-mentioned annulus, providing at least one annular opening adjacent an upper end of the fusion chamber between the second annulus and the interior of the fusion chamber, and forming a thin sheet of the selected material which flows from the upper end of said fusion chamber downwardly along the inner wall surface of the upper section of the fusion chamber above the upright cylindrical section thereof and mixes with the flowing wall by directing the material upwardly through the second annulus and inwardly through the at least one annular opening located adjacent the upper end of the fusion chamber. 2. The method defined in claim 1, additionally including the step of forming the selected material from the group consisting of liquid lithium and liquid lithium-lead mixture. 3. The method defined in claim 1, additionally including the step of forming the selected material from materials that have a melting temperature of less than about 200.degree. C. to effectively maintain the fluid state thereof, have a sufficiently low vapor pressure to maintain an adequate vacuum at operating temperatures (&gt;400.degree. C.), and have neutronic characteristics that permit an adequate tritium breeding ratio to be achieved. 4. The method defined in claim 1, wherein the step of recirculating the material is carried out by material transport mechanisms. 5. The method defined in claim 1, wherein the step of recirculating the material is carried out by at least one recirculation pump. 6. In an inertial confinement reactor having a vessel which includes a first wall having an inner surface forming a chamber therein and provided with target injection means, and means for imploding targets injected into the chamber, the improvement comprising: means defining an annulus exterior of and extending about a portion of said first wall, said first wall including an upright cylindrical section and an annular upper portion located above said upright cylindrical section and separate therefrom, said annulus extending around substantially the entire upright cylindrical section of said chamber, said upright cylindrical section having an annular opening located adjacent an upper portion of said upright cylindrical section of said chamber providing open communication between said chamber and said annulus, said upper annular portion having an annular opening into said chamber, means for protecting the inner surface of said first wall defining said upright cylindrical section of said chamber by forming a flowing wall of material which flows along the inner surface of substantially the entire upright cylindrical section of said chamber, means for recirculating the material from a lower portion of said chamber upwardly through said annulus and inwardly through said at least one annular opening in said upper cylindrical section forming a waterfall effect and maintaining a continuous flowing wall of the material along said upright cylindrical section of said chamber toward said lower portion of said chamber, means for directing a portion of said material to said annular opening in said upper portion for forming a thin sheet of said material which flows downwardly along substantially the entire inner surface of said annular upper portion of said first wall above said upright cylindrical section and mixes with said flowing wall. 7. In an inertial confinement system having a vessel which includes a first wall having an inner surface forming a chamber therein and provided with target injection means, and means for imploding targets injected into the chamber, the improvement comprising: means defining an annulus exterior of and extending about a portion of said first wall, said chamber including an upright cylindrical section, said annulus extending around substantially the entire upright cylindrical section of said chamber, said first wall having at least one annular opening located adjacent an upper portion of said upright cylindrical section of said chamber providing open communication between said chamber and said annulus, means for protecting the inner surface of said first wall defining said upright cylindrical section of said chamber by forming a flowing wall of material which flows along the inner surface of substantially the entire upright cylindrical section of said chamber, means for recirculating the material from a lower portion of said chamber upwardly through said annulus and inwardly through said at least one annular opening in said first wall forming a waterfall effect and maintaining a continuous flowing wall of the material toward said lower portion of said chamber, means for forming a second annulus exterior of said first wall and extending from and in open communication with said first-mentioned annulus to adjacent an upper portion of said chamber above said upright cylindrical section thereof and forming at least one annular opening into said upper portion of said chamber, said material recirculating means also directing material upwardly through said second annulus and inwardly through said at least one annular opening in said upper portion of said chamber forming a thin layer of said material which flows downwardly along said inner surface of said first wall forming said upper portion of said chamber above said upright cylindrical section into said flowing wall. 8. The improvement defined in claim 6 or 7, wherein said material is in liquid form, and wherein said material recirculating means comprises a recirculation pump. 9. The improvement defined in claims 6 or 7, wherein said material is selected from the group consisting of liquid lithium and liquid lithium-lead.