Abstract: Alternative designs for a modular test reactor are presented. In one aspect, a molten fuel salt nuclear reactor includes a vessel defining a reactor volume, the vessel being open-topped and otherwise having no penetrations. A neutron reflector is provided within the vessel and displacing at least some of the reactor volume, the neutron reflector defining a reactor core volume. A plurality of heat exchangers are contained within the vessel above the neutron reflector. A flow guide assembly is provided within the neutron reflector that includes a draft tube draft tube separating a central portion of the reactor core volume from an annular downcomer duct. Fuel salt circulates from the reactor core volume, through the heat exchangers, into the downcomer duct and then back into the reactor core volume.

Abstract: Alternative designs for a modular test reactor are presented. In one aspect, a molten fuel salt nuclear reactor includes a vessel defining a reactor volume, the vessel being open-topped and otherwise having no penetrations. A neutron reflector is provided within the vessel and displacing at least some of the reactor volume, the neutron reflector defining a reactor core volume. A plurality of heat exchangers are contained within the vessel above the neutron reflector. A flow guide assembly is provided within the neutron reflector that includes a draft tube draft tube separating a central portion of the reactor core volume from an annular downcomer duct. Fuel salt circulates from the reactor core volume, through the heat exchangers, into the downcomer duct and then back into the reactor core volume.

Abstract: A molten chloride fast reactor (MCFR) includes a plurality of reflectors defining a central core having a core geometric center. A flow channel fluidically connected to the central core. The flow channel includes an outlet flow channel downstream of the central core and an inlet flow channel upstream from the central core. A primary heat exchanger (PHX) disposed outside the central core and between the outlet flow channel and the inlet flow channel. The MCFR also includes a decay heat heat exchanger (DHHX). At least a portion of the DHHX is disposed above the core geometric center, and a fuel salt is configured to circulate at least partially through the outlet flow channel, the DHHX, the PHX, the inlet flow channel, and the central core.

Abstract: Designs for a low power, fast spectrum molten fuel nuclear reactor that can be used to advance the understanding of molten salt reactors, their design and their operation are described. Furthermore, the designs described may be adapted to extra-terrestrial use as described herein for use as a low-gravity, moon-, Mars-, or space-based power generator. These low power reactors include a reactor core volume defined by a radial neutron reflector enclosed in a reactor vessel, in which heated fuel salt flows from the reactor core through a duct between the radial neutron reflector and the reactor vessel and back into the reactor core. Heat generated from the fission in the reactor core is transferred from the molten fuel through the reactor vessel to a coolant, in the case of an experimental design, or directly to an extra-terrestrial environment, in the case of an extra-terrestrial design.

Abstract: A molten chloride fast reactor (MCFR) includes a plurality of reflectors defining a central core having a core geometric center. A flow channel fluidically connected to the central core. The flow channel includes an outlet flow channel downstream of the central core and an inlet flow channel upstream from the central core. A primary heat exchanger (PHX) disposed outside the central core and between the outlet flow channel and the inlet flow channel. The MCFR also includes a decay heat heat exchanger (DHHX). At least a portion of the DHHX is disposed above the core geometric center, and a fuel salt is configured to circulate at least partially through the outlet flow channel, the DHHX, the PHX, the inlet flow channel, and the central core.

Abstract: A system and method of selectively fastening a substrate to a limited travel staging system are disclosed. In accordance with one aspect of a substrate holder, a securing mechanism may be manually or automatically moved in a repeatable manner such that a selected region of a substrate can be moved into the precision travel range of a highly accurate staging system. Some embodiments of a substrate holder may comprise an indexing system enabling referenced movements such that one or more selected substrate regions may be moved relative to the stage.

Abstract: A fluorescence microscopy system and method allow selective and repeatable switching between Köhler illumination, providing a relatively large field of view, and Critical Illumination, providing a relatively higher axial resolution. This switching or toggle function may be facilitated by a feature associated with an alignment module that allows the focus of the fiber tip, for example, to be selectively and repeatably transitioned between the back aperture of the objective lens and the object plane without losing optical alignment.

Abstract: A processor retention assembly is disclosed. An embodiment of the processor retention assembly includes a first dual processor retention module and a second dual processor retention module. A connecting member is attached to the first dual processor retention module at a first end and is attached to the second dual processor retention module at a second end. In accordance with another embodiment of the present invention, covers are hingedly attached to each of the first and second dual processor retention modules.

Abstract: Measuring the difference in dihedral angles formed by planes defined by a pair of passive sensors, a target, and a reference plane to determine whether both sensors are tracking the same target. The reference plane is defined by the positions of the two sensors and the origin of the system's reference coordinates. A sensor-target plane is determined by the sensor's position, the position of the other sensor, and the position of its target. If the target is the same for both sensors, the sensor-target planes will be substantially the same and their dihedral angles formed with the reference plane will be substantially equal. If the target is not the same for both sensors, then a statistic relating to the dihedral angles with the reference plane will be significant. A decision based on the dihedral angle statistic and a statistic derived from the tracking predictor, e.g., the Kalman Filter Residual, can be made whether the target is maneuvering, has been lost, is correctly tracked.

Abstract: A heat transfer module, comprises: a heat generating unit and a heat receiving unit which are separated by a gap; a compliant body, having microscopic voids therethrough, which is compressed into the gap; and a liquid metal alloy that is absorbed in the microscopic voids in the compliant body. Further, the heat transfer module also includes a seal ring in the gap which surrounds the compliant body and which is spaced apart from the compliant body; and, the compliant body is intentionally compressed so much that a portion of the liquid metal alloy is squeezed from the compliant body into the space between the compliant body and the seal ring. Squeezing liquid metal alloy from the compliant body lowers the thermal resistance between the heat generating unit and the heat receiving unit by increasing the area through which heat is transferred and by increasing the thermal conductivity through the compliant body.

Abstract: A sub-assembly for transferring heat between a heat generating unit and heat receiving unit which are separated by a gap, comprises: a compliant body having microscopic voids therethrough; a liquid metal alloy that is absorbed in the microscopic voids in the compliant body; a seal ring which surrounds the compliant body; and, a retaining member which is attached to the compliant body and the seal ring, and which holds the compliant body spaced apart from the seal ring. This sub-assembly is placed in the gap between the two units and compressed to the point where liquid metal alloy is squeezed out of the compliant body. Squeezing liquid metal alloy from the compliant body lowers the thermal resistance between the heat generating unit and the heat receiving unit by increasing the area through which heat is transferred and by increasing the thermal conductivity through the compliant body.

Abstract: An integrated circuit package includes an integrated circuit chip, a substrate which holds the chip, and a heat conduction mechanism which provides a path for conducting heat from the chip to a fluid medium; wherein the heat conduction mechanism is characterized as having a pressed joint which is comprised of: 1) a member that is made primarily of aluminum or copper, having a solid polysiloxane coating of less than 200 .ANG. thickness, and 2) a liquid metal alloy in contact with the coating. This solid coating, on the aluminum or copper member, is fabricated without any expensive equipment by the steps of: 1) forming a liquid coating of a polysiloxane solution on the aluminum or copper member; and 2) baking that member with its liquid coating at temperatures of 100.degree. C.-300.degree. C. for 0.5 hours-3.0 hours. Thereafter the integrated circuit package is completed by placing the member with its solid coat in the heat conducting path such that a liquid metal alloy is in contact with the solid coat.

Abstract: A computer method for accurate target tracking by a faster method for hit-to-target data association. The method involves using an approximation of a weighted centroid of hits to update the calculated tracks. The result, while losing theoretical accuracy since it approximates the calculation, produces fast calculations. Further, the calculated result has sufficient accuracy for most practical applications.