A PCCS condenser may include a first and a second stage condenser. Each of the first and second stage condensers may include channels in fluid communication between an inlet and an outlet header. The inlet header of the first stage condenser may be configured to receive a fluid mixture through a first inlet opening. The channels may be configured to condense water from the fluid mixture flowing through the channels from the inlet header to the outlet header, respectively, of the first and second stage condenser. The PCCS condenser may include a catalyst in at least one of the outlet header of the first stage condenser or the inlet header of the second stage condenser. The catalyst may catalyze a reaction for forming water from hydrogen and oxygen in the fluid mixture. The outlet header of the second stage condenser may be in fluid communication with a combined vent-and-drain line.

According to one embodiment, a heat transport apparatus includes an evaporator, a cooling unit, a channel structure, and a heating mechanism. The evaporator vaporizes a refrigerant by heat generated by a heat-generating element. The cooling unit is provided above the evaporator and cools and condenses the refrigerant vaporized in the evaporator. The channel structure constitutes a channel through which the refrigerant circulates between the evaporator and the cooling unit. The heating mechanism heats the cooling unit and suppresses solidification of the refrigerant at the cooling unit.

A method for the manufacture of a three-dimensional object using a refractory matrix material is provided. The method includes the additive manufacture of a green body from a powder-based refractory matrix material followed by densification via chemical vapor infiltration (CVI). The refractory matrix material can be a refractory ceramic (e.g., silicon carbide, zirconium carbide, or graphite) or a refractory metal (e.g., molybdenum or tungsten). In one embodiment, the matrix material is deposited according to a binder-jet printing process to produce a green body having a complex geometry. The CVI process increases its density, provides a hermetic seal, and yields an object with mechanical integrity. The residual binder content dissociates and is removed from the green body prior to the start of the CVI process as temperatures increase in the CVI reactor. The CVI process selective deposits a fully dense coating on all internal and external surfaces of the finished object.

A pump assisted heat pipe may combine the low mass flow rate required of latent heat pipe transfer loops with a hermetically sealed pump to overcome the typical heat pipe capillary limit. This may result in a device with substantially higher heat transfer capacity over conventional pumped single-phase loops, heat pipes, loop heat pipes, and capillary pumped loops with very modest power requirements to operate. Further, one or more embodiments overcome the gravitation limitations in the conventional heat pipe configuration, e.g., when the heat addition zone is above the heat rejection zone, the capillary forces are required to transfer the liquid from the heat rejection zone to the heat addition zone against gravity.

A plurality of heat transfer pipes; a first header and a second header to which both ends of each of the heat transfer pipes that are disposed in parallel are fixed, respectively; a plurality of plate-shaped fins through which each of the heat transfer pipes is penetrated and that are provided at intervals in a direction in which the heat transfer pipes extend between the first header and the second header; and a fan that circulates an airflow between the plate-shaped fins are included. The first header and the second header are formed to be sectioned into multiple rows, the heat transfer pipes are disposed densely in an sectioned area of the first header and the second header, and the heat transfer pipes are disposed sparsely in an area between the sectioned areas of the first header and the second header.

A plurality of heat transfer pipes; a first header and a second header to which both ends of each of the heat transfer pipes that are disposed in parallel are fixed, respectively; a plurality of plate shaped fins through which each of the heat transfer pipes is penetrated and that are provided at intervals in a direction in which the heat transfer pipes extend between the first header and the second header; and a fan that circulates an airflow between the plate shaped fins are included. The first header and the second header are formed to be sectioned into multiple rows, the heat transfer pipes are disposed densely in an sectioned area of the first header and the second header, and the heat transfer pipes are disposed sparsely in an area between the sectioned areas of the first header and the second header.

Systems, structures, devices, and fabrication processes for ceramic matrix composites suitable for use in a nuclear reactor environment and other applications requiring materials that can withstand high temperatures and/or highly corrosive environments are disclosed. In one aspect, a ceramic composite structure is provided. The structure comprises a chamber including an external shell and a hollow space inside the external shell. The external shell includes an inner composite layer including a first composite structure, a middle composite layer placed outside of the inner composite layer, the middle composite layer including a second composite structure that is different from the first composite structure, and an outer monolithic layer that has a spatially uniform material property and placed outside of the middle composite layer.

A nuclear reactor includes a vessel incorporating at least one primary power heat exchanger for cooling the primary liquid of the nuclear reactor during the normal operation of the reactor and at least one primary passive safety heat exchanger for cooling the primary liquid of the nuclear reactor in the event of a malfunction in the normal cooling of the primary liquid of the reactor. The vessel includes a compartment arranged in the thickness thereof, wherein the primary passive safety heat exchanger is at least partially contained inside the compartment.

A nuclear reactor includes a heat exchanger that transfers thermal energy from a primary reactor coolant to a secondary coolant. The heat exchanger is formed with a hot flow channel, a cold flow channel, and a porous layer between the hot flow channel and the cold flow channel. The porous layer may be thermally insulative to reduce the efficiency of thermal energy transfer from the hot flow channel to the cold flow channel. The porous layer may have a control gas passed therethrough that can be tailored to control the thermal energy transfer through the porous layer. The control gas can be tested for leakage within the heat exchanger. The control gas may also be used to sequester fission or activation products.

A heat pipe configured to remove heat from a nuclear reactor core is disclosed herein. The heat pipe can include an inner housing defining an inner volume configured to accommodate a heat source and an outer housing configured about the inner housing and the heat source. A wick can be positioned between at least a portion of the inner housing and at least a portion of the outer housing, wherein the wick can include a capillary material, and wherein the wick can define an intermediate volume between the inner housing and the outer housing. A working fluid can be positioned within the intermediate volume, wherein the working fluid can evaporate at a first end of the heat pipe and condense at a second end of the heat pipe adjacent to a heat exchanger, and wherein the wick can return condensed working fluid to the first end of the heat pipe.