An igniter apparatus which generates a high speed buoyancy induced vortex to funnel hydrogen and air from the surrounding onto the igniter core where an igniter core heats up to the auto ignition temperature by the exothermic catalytic oxidation of hydrogen on its surface. Water (vapor) is formed as the product, which inhibits the oxidation reaction, if not stripped away from the catalyst surface. The high velocity of the vortex ensures the stripping of the boundary layer of steam that is formed by the reaction, thus ensuring more active sites are available for hydrogen oxidation. The vortex is formed by channeling an upward draft into a vortex by guided fins. The upward draft is formed by a plate, which is also coated with a hydrogen recombination catalyst. The plate becomes hot by the same catalytic oxidation reaction in the presence of air containing hydrogen.

An igniter apparatus which generates a high speed buoyancy induced vortex to funnel hydrogen and air from the surrounding onto the igniter core where an igniter core heats up to the auto ignition temperature by the exothermic catalytic oxidation of hydrogen on its surface. Water (vapor) is formed as the product, which inhibits the oxidation reaction, if not stripped away from the catalyst surface. The high velocity of the vortex ensures the stripping of the boundary layer of steam that is formed by the reaction, thus ensuring more active sites are available for hydrogen oxidation. The vortex is formed by channeling an upward draft into a vortex by guided fins. The upward draft is formed by a plate, which is also coated with a hydrogen recombination catalyst. The plate becomes hot by the same catalytic oxidation reaction in the presence of air containing hydrogen.

An ion exchange system includes one or more strategies to reduce the amount of hydrogen gas inside an ion exchange column when the column is offline or disposed of. The ion exchange system comprises an ion exchange column including a housing and ion exchange media positioned in the housing. The ion exchange column can include one or more of the following: (1) an oxide material that limits the production of hydrogen gas from radiolysis, (2) a hydrogen scavenging material that removes or scavenges hydrogen gas inside the column, and (3) a hydrogen catalytic material that catalyzes the reaction of hydrogen and oxygen inside the column.

An ion exchange system includes one or more strategies to reduce the amount of hydrogen gas inside an ion exchange column when the column is offline or disposed of. The ion exchange system comprises an ion exchange column including a housing and ion exchange media positioned in the housing. The ion exchange column can include one or more of the following: (1) an oxide material that limits the production of hydrogen gas from radiolysis, (2) a hydrogen scavenging material that removes or scavenges hydrogen gas inside the column, and (3) a hydrogen catalytic material that catalyzes the reaction of hydrogen and oxygen inside the column.

The hydrogen combustion catalyst includes a catalyst metal supported on a carrier made of an inorganic oxide, wherein: a functional group having at least one alkyl group with three or less carbon atoms is bonded to a terminal of a hydroxyl group on the carrier surface by substitution; platinum and palladium are supported as the catalyst metal; and a chlorine content is 300 ppm to 2,000 ppm per 1 mass % of the total supported amount of a supported amount of platinum and a supported amount of palladium. The total supported amount of platinum and palladium is preferably 0.1 to 5.0 mass % based on mass of a whole catalyst. In the hydrogen combustion catalyst according to the present invention, when treating a gas that contains iodine and hydrogen, catalyst poisoning by iodine is suppressed.

A process of producing a catalyst entails providing an alumina substrate and adhering a noble metal consisting of either platinum or palladium to an outer surface of the alumina substrate to form a surface coating without penetrating into a central portion of the substrate. The noble metal may be calcined in a presence of organic compounds that increase the viscosity of a liquid carrying the noble metal to thereby minimize penetration into the central portion of the substrate and that also increase the yield of metal oxides during calcination thereby making the catalyst more active.

A process of producing a catalyst entails providing an alumina substrate and adhering a noble metal consisting of either platinum or palladium to an outer surface of the alumina substrate to form a surface coating without penetrating into a central portion of the substrate. The noble metal may be calcined in a presence of organic compounds that increase the viscosity of a liquid carrying the noble metal to thereby minimize penetration into the central portion of the substrate and that also increase the yield of metal oxides during calcination thereby making the catalyst more active.

An ion exchange system includes one or more strategies to reduce the amount of hydrogen gas inside an ion exchange column when the column is offline or disposed of. The ion exchange system comprises an ion exchange column including a housing and ion exchange media positioned in the housing. The ion exchange column can include one or more of the following: (1) an oxide material that limits the production of hydrogen gas from radiolysis, (2) a hydrogen scavenging material that removes or scavenges hydrogen gas inside the column, and (3) a hydrogen catalytic material that catalyzes the reaction of hydrogen and oxygen inside the column.

According to an embodiment, a nuclear plant has: an outer well; an in-Containment Atmosphere Dilution System to inject a gas that has a low concentration of oxygen in the outer well into a containment vessel; an accumulator containing pressurized oxygen therein; and a passive containment cooling system including: a scrubbing pool arranged in the outer well; a cooling water pool installed above a dry well and the outer well; a heat exchanger partly submerged in a cooling water; a wet well gas supply pipe that is connected to an inlet plenum of the heat exchanger at one end and connected to a wet well gas phase at the other end; and a gas vent pipe that is connected to an outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at the other end.

According to an embodiment, a nuclear plant has: an outer well; an in-Containment Atmosphere Dilution System to inject a gas that has a low concentration of oxygen in the outer well into a containment vessel; an accumulator containing pressurized oxygen therein; and a passive containment cooling system including: a scrubbing pool arranged in the outer well; a cooling water pool installed above a dry well and the outer well; a heat exchanger partly submerged in a cooling water; a wet well gas supply pipe that is connected to an inlet plenum of the heat exchanger at one end and connected to a wet well gas phase at the other end; and a gas vent pipe that is connected to an outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at the other end.