Abstract: A method for preventing corrosion of a spent nuclear fuel canister by using electrolytic corrosion protection, according to the present invention, has an effect of enabling a semi-permanent operation and, particularly, has effects of preventing oxidation and corrosion problems of a canister made of a metal material, in consideration of various environmental variables that may cause corrosion, and ensuring the structural stability of the canister so as to enable a semi-permanent operation.

Abstract: A heat pipe has an evaporator portion, a condenser portion, and at least one flexible portion that is sealingly coupled between the evaporator portion and the condenser portion. The flexible portion has a flexible tube and a flexible separator plate held in place within the flexible tube so as to divide the flexible tube into a gas-phase passage and a liquid-phase artery. The separator plate and flexible tube are configured such that the flexible portion is flexible in a plane that is perpendicular to the separator plate.

Abstract: The present disclosure is directed to a nuclear thermionic avalanche cell (NTAC) systems and related methods of generating energy comprising a radioisotope core, a plurality of thin-layered radioisotope sources configured to emit high energy beta particles and high energy photons, and a plurality of NTAC layers integrated with the radioisotope core and the radioisotope sources, wherein the plurality of NTAC layers are configured to receive the beta particles and the photons from the radioisotope core and sources, and by the received beta particles and photons, free up electrons in an avalanche process from deep and intra bands of an atom to output a high density avalanche cell thermal energy through a photo-ionic or thermionic process of the freed up electrons.

Abstract: Methods and apparatus are described for extracting and storing electrical energy from the gaseous discharge of a firearm. In one embodiment a muzzle device is provided comprising of at least one thermoelectric generator which generates electric power, to be stored in a battery, using heat transferred from the gaseous discharge of a firearm to the thermoelectric generator by a heat sink.

Abstract: A temperature sensor (1) for gas burner (2) having a thermocouple (11) comprising electric conductors (15) and a connection element (12) to connect to the burner (2) associated with a free end (18) of such thermocouple (11), said connection element (12) being suitable for being inserted inside a seat of the sensor (8) formed inside a wall (4) of the burner (2) and having a first end (26) suitable for being placed at the outer surface (6) of the burner (2), said thermocouple (11) being inserted inside a blind hole (29) of the connection element (12) which opens at a second end (28) of said connection element (12). Said blind hole (29) ends with at least one part (31) convergent towards an end zone (K) of the hole (29), said part (31) getting in contact with the thermocouple (11) inserted inside the connection element, the connection element (12) being made from an iron-chrome-aluminum alloy. An assembly comprising such temperature sensor and a burner is also claimed.

Abstract: A thermoelectric assembly includes first and second shunts spaced apart from one another in a through-plane direction. At least one of the first and second shunts having a shunt area in an in-plane direction. P-n pellets interconnect the first and second shunts electrically in series with one another in the in-plane direction. The p-n pellets have faces that engage the first and second shunts. At least one of the faces have a pellet area. The pellet area is substantially less than the shunt area.

Abstract: An example spacecraft includes a first arm having a first end pivotably coupled to the spacecraft and a second end. The example spacecraft includes a first thruster rotatably coupled to the second end of the first arm. The first arm extends from the first pivot point along a first edge of an anti-nadir face of the spacecraft when the first arm is in a stowed position. The first arm is configured to pivot between the stowed position, a first extended position in which the first arm extends outward from the spacecraft relative to the first edge, and a second extended position in which the first arm extends along a third edge of the anti-nadir face and the first thruster is disposed outward of a second edge of the anti-nadir face opposite the first edge.

Abstract: A passive safety system for removing decay heat from a nuclear power system may comprise a shroud structure and a heat generator that is within the shroud structure. A thermoelectric device may be disposed in thermal contact with the heat generator. The thermoelectric device is configured to generate a voltage based on a temperature difference between opposite parts of the thermoelectric device. A fan arrangement is disposed above the heat generator and in electrical connection with the thermoelectric device. The fan arrangement is configured to increase a coolant flow through the coolant passage to the outlet opening based on the voltage from the thermoelectric device.

Abstract: Systems and methods for power generation for an aircraft are provided. In one example embodiment, a power generation system for an aircraft includes a thermionic generator arranged to receive heat from at least one heat source. The thermionic generator is configured to generate electrical power for one or more aircraft systems based at least in part on the heat received from the at least one heat source. The power generation system further includes a thermoelectric generator arranged to receive waste heat from the thermionic generator. The thermoelectric generator is configured to generate electrical power for one or more aircraft systems based at least in part on the waste heat received from the thermionic generator.

Abstract: The present invention relates to a method and a device (1) for cooling an arrangement (2) using a cold head (3), with a thermal cooling of the unit (2) to be cooled by means of the thermosiphon principle. At the same time, heat is conducted via a mechanical heat bridge (5), which provides a direct thermal connection from the cold head (3) to the unit (2) to be cooled.

Abstract: This invention relates to a process for controlling a dental firing furnace in which a temperature in a firing chamber of the dental furnace is detected by means of a temperature sensor, and in which a heating element that is controlled by a control device controls the heating of the firing chamber of the dental firing furnace based on the measurement result of the temperature sensor. In this process a dental restoration part is received within the firing chamber of the dental furnace. The heating is controlled so that the dental restoration part reacts exothermically, emitting additional heat. The additional heat is detected by the temperature sensor which is pointed at the dental restoration part and the control device delivers at least one signal representing the additional heat, such as in the form of a display signal and/or control signal.

Abstract: A temperature detecting device (101) includes: a detecting unit (11) which detects a temperature of a heat source (1); a power generation unit (12) which includes a thermoelectric conversion element (3) and is spaced from the detecting unit (11); a first heat transfer unit (41) that transfers heat or cold of the heat source (1) to the power generation unit (12); a radiator (13) which is remote from the power generation unit (12) so as to radiate heat or cold to outside; a second heat transfer unit (42) that receives heat or cold from the power generation unit (12) and that transfers the heat or cold to the radiating unit (13); and an output unit (14) that outputs a result of the measurement made by the temperature receiving element (2). The thermoelectric conversion element (3) generates electric power by way of a temperature difference between a surface (3a) and a surface (3b) and supplies electric power to the temperature receiving element (2) and the output unit (14).

Abstract: Systems, methods, and apparatus for laser communications following an atmospheric event. In one or more embodiments, the disclosed method involves transmitting, by at least one laser on at least one first satellite, at least one first transmit signal. The method further involves receiving, by at least one detector on at least one first satellite, at least one first receive signal. In one or more embodiments, at least one first satellite is in super-geosynchronous earth orbit (S-GEO). In at least one embodiment, at least one first transmit signal and at least one first receive signal are laser signals. Further, the method involves adapting, by at least one first processor on at least one first satellite, at least one first transmit signal according to at least one atmospheric event.

Abstract: A solid-state nuclear energy conversion system includes a crystalline insulator bombarded with radiation to create electron-hole pairs. A voltage source provides a potential bias across the crystalline insulator, causing electrons and holes to collect at opposing ends. A diode is incorporated in a circuit including the crystalline insulator, voltage source, and a load, inhibiting current flow from the voltage source to the load. Thus, a radiation-driven current flows to the load.

Abstract: A method, system, and apparatus for the selective transfer of thermoelectrically generated electric power to operation systems of a nuclear reactor system including thermoelectrically converting nuclear reactor generated heat to electrical energy and selectively transferring the electrical energy to at least one operation system of the nuclear reactor system.

Abstract: A concrete storage module (26) is adapted to slideably receive a cylindrical canister assembly (12) therein. Heat dissipation fins (62) and a tubular heat shield (96) are disposed within the module to help dissipate heat emitted from the nuclear fuel assemblies stored in the canister to air flowing through the module. The canister assembly (12) is composed of a basket assembly (70) constructed from multi-layer structural plates disposed in cross-cross or egg carton configuration. A single port tool (106) is provided for draining water from the canister (12) and replacing the drain water with make-up gas. The single port tool is mounted in the cover (100) of the canister and is in fluid flow communication with the interior of the canister.

Abstract: Set forth herein are methods and systems for determining a rechargeable (i.e., secondary) battery's capability in real time, including how much power and energy can be discharged or charged, by compensating for the limitations of the standard battery model for cathode electron and ion transport restrictions in a solid-state battery. Set forth herein is also an equivalent circuit for each layer of a layered cathode (i.e., positive electrode) which is created using resistive, capacitive, and storage elements, including a state-of-charge (SOC) state variable and an SOC-dependent voltage source. In some embodiments, each layer is connected to adjoining layers using resistive elements to model ion and electron transport. In some embodiments, bulk ohmic resistance and ion exchange external to the electrode is represented using a Randles cell equivalent circuit.

Abstract: High performance thin film thermoelectric couples and methods of making the same are disclosed. Such couples allow fabrication of at least microwatt to watt-level power supply devices operating at voltages greater than one volt even when activated by only small temperature differences.

Abstract: A multi-layer thermoelectric module and a fabricating method thereof are provided. The module includes two thermoelectric element sets and a metal electrode set, in which the thermoelectric element sets are corresponding to different operating temperature ranges. Each thermoelectric element set includes a thermoelectric unit, an interfacial adhesion layer, a diffusion barrier layer and a high melting-point metal layer. In the method, the thermoelectric unit, the interfacial adhesion layer, and the diffusion barrier layer are sequentially formed on the thermoelectric unit. Then, two high melting-point metal layers are formed respectively on the electrode layers of the metal electrode set.

Abstract: A power converter comprises a nuclear radiation emitter having a first side and a second side, wherein the nuclear radiation emitter comprises a radiation-emitting radioisotope, a plurality of semiconductor substrates disposed over the first side of the nuclear radiation emitter, wherein each of the plurality of semiconductor substrates comprises a junction for converting nuclear radiation particles to electrical energy, and at least one high-density layer, wherein the high density layer has a density that is higher than a density of the semiconductor substrates, and wherein the high-density layer is disposed between two of the plurality of semiconductor substrates.

Abstract: According to one embodiment, an energy conversion device comprises a nuclear battery, a light source coupled to the nuclear battery and operable to receive electric energy from the nuclear battery and radiate electromagnetic energy, and a photocell operable to receive the radiated electromagnetic energy and convert the received electromagnetic energy into electric energy. The nuclear battery comprises a radioactive substance and a collector operable to receive particles emitted by the radioactive substance.

Abstract: A power converter is provided and includes a heat collector surface, n- and p-legs formed of n- and p-type thermoelectric materials, respectively, which are each disposed in thermal communication with the heat collector surface, parallel electric busses electrically coupled to the n- and p-legs and a housing, which is electrically decoupled from the busses, to support the heat collector surface at a predefined distance from a heat pipe.

Abstract: An apparatus comprising a structure and an energy harvesting device. The structure is configured to have a first portion and a second. The energy harvesting device is formed as part of the structure. The energy harvesting device is configured to generate an electrical current when a difference in temperature occurs between the first portion and the second portion.

Abstract: An electricity generation apparatus is disclosed. An exemplary apparatus includes a plasma container for containing a plasma sustained by radioactive decay. The plasma container has an inlet through which, in use of the apparatus, water can be introduced to the plasma container, and an outlet through which, in use of the apparatus, material can be expelled from the container. The exhausted material can include hydrogen and oxygen resulting from the dissociation of water molecules caused by interactions within the plasma. A separator can separate hydrogen from the material exhausted from the plasma container, which separator is coupled to the outlet, and a generator can generate electricity using the hydrogen as a fuel.

Abstract: A low energy nuclear thermoelectric system for a vehicle which provides a cost-effective and sustainable means of transportation for long operation range with zero emission using an onboard low energy nuclear reaction thermal generator. The present invention generally includes a thermal generator within a thermal enclosure case, an energy conversion system linked with the thermal generator, an energy storage system linked with the energy conversion system, a cooling system and a central control system. The thermal generator reacts nickel powder with hydrogen within a reactor chamber to produce heat. The heat is then transferred to the energy conversion system to be converted into electricity for storage in the energy storage system. The cooling system provides cooling for the various components of the present invention and the control system regulates its overall operation. The present invention may be utilized to power a vehicle in an efficient, sustainable and cost-effective manner.

Abstract: A system which can efficiently control the temperature of the battery module, and also can easily control the temperature in the intense environment by actively adapting the exterior environment. The system for controlling temperature of a secondary battery module includes a housing receiving a plurality of unit batteries. The housing has an inlet and an outlet. A heat transfer member is in contact with the unit batteries. The heat transfer member has a portion exposed to a heat transfer medium duct formed inside the housing, and a temperature controller is mounted in the heat transfer member to control temperature of the unit batteries.

Abstract: A thermoelectric conversion module which has a P-type thermoelectric conversion material and an N-type thermoelectric conversion material electrically connected to each other. The P-type thermoelectric conversion material and the N-type thermoelectric conversion material are joined with insulating material particles (ceramic spherical particles) interposed therebetween, so as not to be electrically connected to each other.

Abstract: An apparatus, system and method provides electrical power in a subterranean well. A radioisotope thermoelectric generator may be positioned and installed in a downhole location in a wellbore. The location of the radioisotope thermoelectric generator may be within a completion string. A radioisotope thermoelectric generator comprises a core having a radioisotope for producing heat, and a thermocouple. The thermocouple comprises at least two different metals, and is positioned adjacent to the core. The radioisotope thermoelectric generator flows heat from the core to the thermocouple to produce electricity that may be stored in an energy storage device, or used to power a component. The produced electrical power may be employed to activate downhole sensors, valves, or wireless transmitters associated with the operation and production of an oil or gas well.

Abstract: Systems and methods for converting engine heat energy to electricity using a thermoelectric conversion device are provided herein. One example system may include an engine heat source, a thermoelectric conversion device for converting heat into electricity, and a heat pipe. The heat pipe is positioned so that when the temperature of the engine exhaust is too high, the excess heat may be transferred away from the thermoelectric conversion device to the heat sink via the heat pipe.

Abstract: The invention describes a product and a method for generating electrical power directly from nuclear power. More particularly, the invention describes the use of a liquid semiconductor as a means for efficiently converting nuclear energy, either nuclear fission and/or radiation energy, directly into electrical energy. Direct conversion of nuclear energy to electrical energy is achieved by placing nuclear material in close proximity to a liquid semiconductor. Nuclear energy emitted from the nuclear material, in the form of fission fragments or radiation, enters the liquid semiconductor and creates electron-hole pairs. By using an appropriate electrical circuit an electrical load is applied and electrical energy generated as a result of the creation of the electron-hole pairs.

Abstract: The invention describes a product and a method for generating electrical power directly from nuclear power. More particularly, the invention describes the use of a liquid semiconductor as a means for efficiently converting nuclear energy, either nuclear fission and/or radiation energy, directly into electrical energy. Direct conversion of nuclear energy to electrical energy is achieved by placing nuclear material in close proximity to a liquid semiconductor. Nuclear energy emitted from the nuclear material, in the form of fission fragments or radiation, enters the liquid semiconductor and creates electron-hole pairs. By using an appropriate electrical circuit an electrical load is applied and electrical energy generated as a result of the creation of the electron-hole pairs.

Abstract: A fluid tube routes a fluid adjacent to a source of heat to heat the fluid. The heated fluid is passed adjacent to cells which receive infrared radiation from the heated fluid. An anti-corrosion member is positioned on a portion of the tube adjacent to the cells. The anti-corrosion member is spaced from an outer periphery of the tube to provide a chamber between the portion of the tube and the anti-corrosion member.

Abstract: A thermoelectric generator (TEG) and a method of fabricating the TEG are described. The TEG is designed so that parasitic thermal resistance of air and height of legs of thermocouples forming a thermopile can be varied and optimized independently. The TEG includes a micromachined thermopile sandwiched in between a hot and a cold plate and at least one spacer in between the thermopile and the hot and/or cold plate. The TEG fabrication includes fabricating the thermopiles, a rim, and the cold plate.

Abstract: A fluid tube routes a fluid adjacent to a source of heat to heat the fluid. The heated fluid is passed adjacent to cells which receive infrared radiation from the heated fluid. An anti-corrosion member is positioned on a portion of the tube adjacent to the cells. The anti-corrosion member is spaced from an outer periphery of the tube to provide a chamber between the portion of the tube and the anti-corrosion member.

Abstract: The present invention is a self-contained, solar powered heating and cooling system for a building. The collector has an insulated heating chamber, and a light transmissive cover and a thermostatically controlled vent. The chamber contains absorptive columns standing on the floor. An internal liquid conduit exposes the liquid to the heat within the chamber. The collector is connected to a remote thermal reservoir such that a liquid circuit and a separate gas circuit both circulate heated fluid to the reservoir. Heat can be stored in any of a liquid reservoir, thermal mass reservoir and gas reservoir. Wind powered generators and photovoltaic cells provide power for the system or other applications. The thermal reservoir has heat exchangers which deliver stored heat to the building or operate a heat operated refrigeration machine (e.g., a liquid absorption chiller). Additional self sustaining power sources may optionally be incorporated into the present invention.

Abstract: A power system (10) is provided. System (10) generally comprises at least one generator module (100, 100′), and a heat source (200) encircling at least a portion of the generator module (100, 100′). Each generator module (100) includes at least one generator section (110) having a heat exchanger (120) extending axially therefrom. The heat source (200) is defined by a plurality of separable arcuate aeroshell segments (210, 210′) extending angularly about the heat exchanger section (120, 120′) of each generator module (100, 100′) to collectively describe a substantially cylindrical outer contour coaxially oriented thereabout. Each arcuate aeroshell segment (210, 210′) has formed therein at least one fuel compartment (212) extending axially inward from a front axial face (214) thereof in which a radioisotope fuel material (220) is stored and sealed therein by a covering member (230).

Abstract: A power generator includes a current-generating cell having a layer of a fission source of heavy ions and alpha particles, and two semiconductor structures, one on each side of the layer of the fission source. The layer of the fission source is preferably Pu238 or Cf252. The semiconductor structure is preferably a silicon structure such as a silicon P-I-N diode. The cell includes two metal contact layers, each contacting a respective one of the semiconductor structures at a location remote from the layer of the fission source. A voltage source, such as a thermopile operating with heat produced from the current-generating cell, is in electrical communication with the two metal contact layers to apply a collection voltage across the current-generating cell. Two current collector leads are provided, with each current collector lead being in electrical communication with a respective one of the two metal contact layers.

Abstract: A method and apparatus for controlling the temperature of a thermionic reactor over a wide range of operating power, including a thermionic reactor having a plurality of integral cesium reservoirs, a honeycomb material disposed about the reactor which has a plurality of separated cavities, a solid sheath disposed about the honeycomb material and having an opening therein communicating with the honeycomb material and cavities thereof, and a shell disposed about the sheath for creating a coolant annulus therewith so that the coolant in the annulus may fill the cavities and permit nucleate boiling during the operation of the reactor.

Abstract: The present invention is a power cell for directly converting ionizing radiation into electrical energy. The invented isotopic electric converter provides an electrical power source that includes an electronegative material layered in a semiconductor, to form a first region that has a high density of conduction electrons, and an electropositive material also layered in the semiconductor material to form a second region with a high density of holes. Said N-layers region and P-layers region are separated by a neutral zone of semiconductor material doped with a radioactive isotope, such as, but not limited to, tritium. No junction is formed between the N and P layers regions. Rather, the potential gradient across the neutral zone is provided by the difference between the work functions of the electronegative and electropositive electrodes. Electrical contacts are affixed to the respective regions of the first and second type conductivity which become the anode and cathode of the cell, respectively.

Abstract: A radioisotope-powered semiconductor battery comprises a substrate of a crystalline semiconductor material, the material having at least one degree of confinement, and a radioactive power source comprising at least one radioactive element. The power source is positioned relative to the substrate to allow for impingement of emitted particles on the substrate. The semiconductor material may be electronically, structurally or chemically confined. The radioactive element is preferably impregnated within or immediately adjacent the semiconductor material.

Abstract: A method and apparatus for converting radioactive energy into electrical energy is provided and includes a first radioisotope (24) emitting alpha particles and a second radioisotope (28) emitting beta particles. A first plate (16) is positioned proximate the first radioisotope (24) and is adapted for capturing the alpha particles wherein the first plate (16) is positively charged. A second plate (18) is positioned proximate the second radioisotope (28) and is insulated from the first plate (16). The second plate (18) is adapted for capturing the beta particles wherein the second plate (18) is negatively charged for establishing an electrical potential between the first plate (16) and the second plate (18). A housing accommodates the radioisotopes (24,28) and plates (16,18) and has a first contact (40) connected to the first plate (16) and a second contact (42) connected to the second plate (18). An electrical potential is generated between the two contacts (40,42).

Abstract: The detection device includes at least one thermocouple (10) arranged aligned with the bottom head of the vessel of the nuclear reactor, having a first branch (9) made of a first metallic material and at least one second branch (11) made of a second metallic material, different from the first material, welded to a point on the first branch constituting a hot junction of the thermocouple (10). The first branch (9) of the thermocouple has the form of an elongate hollow section. The device furthermore includes means for analyzing the measurements taken by the thermocouples (10).

Abstract: Transition metals (T) of Group VIII (Co, Rh and Ir) have been prepared as semiconductor alloys with Sb having the general formula TSb.sub.3. The skutterudite-type crystal lattice structure of these semiconductor alloys and their enhanced thermoelectric properties results in semiconductor materials which may be used in the fabrication of thermoelectric elements to substantially improve the efficiency of the resulting thermoelectric device. Semiconductor alloys having the desired skutterudite-type crystal lattice structure may be prepared in accordance with the present invention by using vertical gradient freeze techniques, liquid-solid phase sintering techniques, low temperature powder sintering and/or hot-pressing. Measurements of electrical and thermal transport properties of selected semiconductor materials prepared in accordance with the present invention, demonstrated high Hall mobilities (up to 8000 cm.sup.2.V.sup.-1.s.sup.-1), good Seebeck coefficients (up to 400 .mu.VK.sup.-1 between 300.degree. C.

Abstract: The apparatus is a combined Alkali Metal Thermal to Electric Converter (AMTEC) and a thermionic energy converter which are mated by the use of a common heat transfer device which can be a heat pipe, pumped fluid or a simple heat conduction path. By adjusting the heat output surface area of the thermionic converter and the heat input surface area of the AMTEC, the heat transfer device accomplishes not only the transfer of heat from the output of the thermionic converter to the input of the AMTEC, but also the transformation of the heat density to match the requirements of the AMTEC input. The electrical current through the combined devices is also matched by adjusting the heated surface area of the AMTEC.

Abstract: An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

Abstract: An electric battery comprises: a nuclear source of relatively high energy radiation fluence; a semiconductor junction characterized by a curve for this fluence relating minority carrier diffusion length and a damage constant and; an enclosure having a sufficiently low thermal impedance for dissipation of sufficient heat from the nuclear source to permit predetermined degradation of the minority carrier diffusion length initially and predetermined maintenance of the minority carrier diffusion length thereafter; the nuclear source being a radionuclide selected from the class consisting of alpha, gamma and beta emitters; and the curve being substantially logarithmic.

Abstract: An impregnated thermionic cathode includes a porous matrix of sintered tungsten-alloy particles containing less than six percent iridium and/or other platinum-group metal. The pores of the matrix are impregnated with a temporary process impregnant such as molten copper or an organic monomer, and upon solidification is machined to a desired shape. Thereafter the temporary process impregnant is removed, and the matrix pores again infiltrated with a barium oxide such as molten barium aluminate, or other alkaline earth. A thin, iridium-rich surface activating layer, preferably of about 50% iridium, is then applied to the emitting surface. The diffusion of surface activating iridium is substantially blocked; superior emission and lifetime is provided; and the cathode is relatively low cost and easy to fabricate.

Abstract: An electric battery comprises a semiconductor junction incorporating an inorganic crystalline compound of Group III and Group V elements of the Periodic Table characterized by a predetermined annealing temperature for defects therein; a nuclear source of relatively high energy radiation and concomitant heat, which radiation causes generation of such defects in the semiconductor junction; and a thermal impedance enclosure for the nuclear source and the semiconductor-junction for retaining therewithin a sufficient quantity of heat to maintain a functional relationship between the generation of defects and the predetermined annealing temperature during operation.

Abstract: By using the helium generated by the alpha emissions of a thermoelectric generator during space travel for cooling, the thermal degradation of the thermoelectric generator can be slowed. Slowing degradation allows missions to be longer with little additional expense or payload.

Abstract: A high voltage multitube alkali metal thermal electric convertor having a plurality of closely packed tubular cells disposed in a tube sheet in a vessel and electrically connected in series, the tube sheet dividing the vessel into a high pressure high temperature portion having a wick and heater disposed therein and a low pressure low temperature portion having a wick disposed in a condenser from which heat is removed; a pump for transferring liquid metal therebetween and a tab on a wick disposed in the tubular cell to remove excess liquid metal and prevent shorting between the cells.