Provided is a method for treating radioactive iodine contained in steam discharged from a nuclear power facility, including a filling step of filling an air-permeable container with a granulated radioactive iodine adsorbent of zeolite X, wherein ion exchange sites of the zeolite X are substituted with silver so that a size of minute pores of the zeolite X is suited to a size of a hydrogen molecule, and the radioactive iodine adsorbent has a silver content of 36 wt % or more when dried, a particle size of 1020 mesh, a hardness of 94% or more, and a water content of 12 wt % or less when dried at 150 C. for 3 h and thereby reduced in weight; and a flow passing step of passing a flow of the steam discharged from the nuclear power facility, through the container filled with the radioactive iodine adsorbent.

Provided is a method for treating radioactive iodine contained in steam discharged from a nuclear power facility, including a filling step of filling an air-permeable container with a granulated radioactive iodine adsorbent of zeolite X, wherein ion exchange sites of the zeolite X are substituted with silver so that a size of minute pores of the zeolite X is suited to a size of a hydrogen molecule, and the radioactive iodine adsorbent has a silver content of 36 wt % or more when dried, a particle size of 1020 mesh, a hardness of 94% or more, and a water content of 12 wt % or less when dried at 150 C. for 3 h and thereby reduced in weight; and a flow passing step of passing a flow of the steam discharged from the nuclear power facility, through the container filled with the radioactive iodine adsorbent.

A nuclear power plant according to an embodiment comprises: a reactor well; a reactor well upper lid; an operation floor; an operation floor area wall; a standby gas treatment system; and a reactor well exhaust section to release the gas inside the reactor well to the environment without releasing the gas into the operation floor area in an event of a predetermined accident, e.g., causing diminished cooling of a containment vessel or otherwise increasing its temperature. The standby gas treatment system includes: a suction pipe to take in gas inside the reactor building; an exhaust fan; a standby gas treatment system exhaust pipe; a heater that is disposed between the suction pipe and the standby gas treatment system exhaust pipe; and a filter to filter the gas heated by the heater and to send the gas to the standby gas treatment system exhaust pipe.

In a plant including a system which is provided with a steam generator 2, a turbine 3, 5, a condenser 6 and a heater 7 and in which non-deaerated water circulates, and a pipe, the steam generator 2, the heater 7 and 8 of the system which comes into contact with the non-deaerated water is deposited with a protective substance.

A nuclear reactor is provided that includes a vessel; a core provided in the vessel; at least one plate heat exchanger provided in the vessel, with at least one duct for supplying a secondary fluid to the heat exchanger and a duct for discharging the secondary fluid from the heat exchanger, the discharge duct extending through the vessel. The nuclear reactor comprises a device for attaching the heat exchanger to an area of the vessel through which the discharge duct extends.

A power module assembly may include a reactor vessel containing a primary coolant and one or more inlets configured to draw a secondary coolant from the containment cooling pool in response to a loss of power and/or a loss of coolant. One or more outlets may be submerged in the containment cooling pool and may be configured to vent the secondary coolant into the containment cooling pool. A heat exchanger may be configured to remove heat from the primary coolant, wherein the heat may be removed by circulating the secondary coolant from the containment cooling pool through the heat exchanger via natural circulation.

A passive safety system for a nuclear power plant (100) cools the plant after shutdown, even when primary water circulation is disabled. The system comprises a source of compressed gas (112, 805) which can be the system's only source of operating energy, a source of external cooling water (106, 500), and interconnection components. If the reactor overheats, the gas is used to force the cooling water into the reactor's core. The gas can be taken from a highly compressed source and decompressed to a lower pressure suitable for forcing the water from the source, in which case the water can first be used to supply heat to the expanding gas to prevent it from freezing its environment. The system can be located underground or can be portable, e.g., carried on railroad cars or other wheeled conveyances. The system can be located above ground, or in a covered trench (705).

A high temperature gas cooled reactor steam generation system (1) includes a nuclear reactor (2) that has helium gas as a primary coolant and heats the primary coolant by heat generated by a nuclear reaction that decelerates neutrons by a graphite block, a steam generator (3) that has water as a secondary coolant and heats the secondary coolant by the primary coolant via the nuclear reactor (2) to generate steam, a steam turbine (4) that is operated by the steam from the steam generator (3), and a generator (5) that generates electricity according to an operation of the steam turbine (4). Moreover, the system (1) includes pressure adjustment means for setting a pressure of the secondary coolant in the steam generator (3) to be lower than a pressure of the primary coolant in the nuclear reactor (2).

A high temperature gas cooled reactor steam generation system (1) includes a nuclear reactor (2) that has helium gas as a primary coolant and heats the primary coolant by heat generated by a nuclear reaction that decelerates neutrons by a graphite block, a steam generator (3) that has water as a secondary coolant and heats the secondary coolant by the primary coolant via the nuclear reactor (2) to generate steam, a steam turbine (4) that is operated by the steam from the steam generator (3), and a generator (5) that generates electricity according to an operation of the steam turbine (4). Moreover, the system (1) includes pressure adjustment means for setting a pressure of the secondary coolant in the steam generator (3) to be lower than a pressure of the primary coolant in the nuclear reactor (2).

Systems, devices, and methods include a valve actuator to open and close a valve in fluid communication with a fluid control system. The valve actuator includes a motor having windings of wire. The wire includes insulating material disposed over a conductor.