Abstract: An instrument for treating deep malignant brain tumors. A slender conically-tipped yttrium tubular instrument is provided for simultaneous intra-tumor surgery, aspiration, and brachytherapy. Features include: minimally disruptive stereotactic access to the tumor, incremental rotary surgical excision from the center of the tumor, vacuum aspiration of excised matter and fluids through the tubular instrument, intense tumor-confined yttrium-90 beta radiation, and progressive suction collapsing of the tumor. Potential benefits include: tumor bulk reduction, relief of intracranial pressure, confined radiation of marginal tumor extensions, radiation sterilization of the instrument, prevention of seeding, and avoidance of radiation necrosis complications.

Abstract: A nuclear propulsion reactor. A reactor vessel is provided with an annular first core and a cylindrical second core that is radially encompassed by the first core. Nuclear fuel elements in the first core provide first stage heating of propellant as they direct the propellant axially through the first core. The second core, which contains fissionable material in a highly refractory form, is in fluid communication with the first core for receiving the heated propellant. Fission reactions in the second core driven by leakage neutrons from the first core provide second stage heating of the propellant as it passes therethrough. The second core directs the coolant to a propellant nozzle for providing propulsive thrust.

Abstract: A nuclear reactor using gas as a primary coolant and a liquid as a moderator and/or reflector. Gas coolant flows through inlet passages around the outlet plenum to a distributor plate. The gas is directed between fuel element housing thimbles and fuel elements therein, through the fuel elements, and into the reactor outlet plenum. Fins on the thimble housings conduct heat to the gas from a liquid moderator circulating in the core. The use of a liquid moderator enhances safety, allows the fissile material and reactor mass to be reduced and eliminates problems associated with cooling of a solid moderator.

Abstract: A shield for a gas cooled nuclear reactor. The reactor vessel head is provided with two regions of material which act in synergism to reflect neutrons back to the core, attenuate gamma rays and neutrons, and allow heat recovery. The primary region attenuates gamma rays and provides significant neutron attenuation. The secondary region provides the residual neutron attenuation.

Abstract: A porous plug is installed in the central region of a fuel rod of annular fuel pellets and prevents relocation of fuel fragments from the inner surface of each fuel pellet while providing a getter for gases produced in the fuel rod during operation of the nuclear reactor.

Abstract: A gas cooled nuclear fuel element. A plurality of progressively sized rigid porous cylinders nested together in coaxial alignment are provided with varying quantities of nuclear fuel to enhance the power density while remaining within temperature limitations of the fuel and base material.

Abstract: A fusion power monitor including a circulating activation medium being activated as it passes by the fusion reaction. The radioactivity of the activation medium is sensed by a remote detector to give an indication of fusion power level.

Abstract: A method and apparatus for testing characteristics of nuclear fuel pellet interaction with nuclear reactor fuel rod cladding whereby the temperature profile within a nuclear fuel rod is more closely modeled in the test device than in the prior art discloses the use of high frequency microwave radiation to heat the fuel pellets within the cladding and using the cladding itself as a waveguide. Sensors monitor various operating parameters and a water jacket cools the test cladding.