A nuclear reactor is surrounded by a reactor radiological containment structure. Depressurization lines running from the reactor automatically vent the reactor to the containment structure or to a compartment in the containment structure when a low pressure condition exists in the reactor. The depressurization lines include biased-open passive valves and actively actuated isolation valves arranged in series.

A nuclear reactor is surrounded by a reactor radiological containment structure. Depressurization lines running from the reactor automatically vent the reactor to the containment structure or to a compartment in the containment structure when a low pressure condition exists in the reactor. The depressurization lines include biased-open passive valves and actively actuated isolation valves arranged in series.

A containment vessel for containing a reactor pressure vessel, a reactor core, and a steam generator of a pressurized water reactor includes a main body equipped with a polar crane, a diaphragm set above the polar crane that partitions the main body, before and after a loss-of-coolant accident (LOCA), into an upper vessel including a dome part having an open space and a lower vessel isolated from the upper vessel, a pressure suppression chamber including a suppression pool that stores water and a gas phase in communication with the open space, a LOCA vent pipe connecting the suppression pool to the lower vessel, and a vacuum breaker that equalizes pressure by allowing gas flow from the upper to the lower vessel when a pressure difference between the upper and lower vessels exceeds a preset value. The lower vessel contains all equipment and piping constituting a reactor pressure boundary.

A nuclear reactor containment system with passive cooling capabilities. In one embodiment, the system includes an inner containment vessel for housing a nuclear steam supply system and an outer containment enclosure structure. An annular water-filled reservoir may be provided between the containment vessel and containment enclosure structure which provides a heat sink for dissipating thermal energy, in the event of a thermal energy release incident inside the containment vessel, the reactor containment system provides passive water and air cooling systems operable to regulate the heat of the containment vessel and the equipment inside. In one embodiment, cooling water makeup to the system is not required to maintain containment vessel and reactor temperatures within acceptable margins.

A nuclear reactor containment system with passive cooling capabilities. In one embodiment, the system includes an inner containment vessel for housing a nuclear steam supply system and an outer containment enclosure structure. An annular water-filled reservoir may be provided between the containment vessel and containment enclosure structure which provides a heat sink for dissipating thermal energy, in the event of a thermal energy release incident inside the containment vessel, the reactor containment system provides passive water and air cooling systems operable to regulate the heat of the containment vessel and the equipment inside. In one embodiment, cooling water makeup to the system is not required to maintain containment vessel and reactor temperatures within acceptable margins.

An organic iodine trapping apparatus and method efficiently traps organic iodine in a nuclear reactor container vessel. A liquid vessel contains a non-volatile liquid (e.g., ionic liquid or interfacial active agent solution) capable of decomposing organic iodine. An introduction pipe introduces a fluid containing organic iodine in the nuclear reactor container vessel to the non-volatile liquid. The non-volatile liquid is heated by heat in the nuclear reactor container vessel or reaction heat of the fluid in the nuclear reactor container vessel. Then, the trapping apparatus decomposes and traps the organic iodine. The organic iodine trapping method includes heating a non-volatile liquid capable of decomposing organic iodine by heat in the nuclear reactor container vessel or reaction heat of fluid in the nuclear reactor container vessel; making the fluid containing organic iodine pass through the heated non-volatile liquid; and decomposing and trapping the organic iodine in the non-volatile liquid.

An organic iodine trapping apparatus and method efficiently traps organic iodine in a nuclear reactor container vessel. A liquid vessel contains a non-volatile liquid (e.g., ionic liquid or interfacial active agent solution) capable of decomposing organic iodine. An introduction pipe introduces a fluid containing organic iodine in the nuclear reactor container vessel to the non-volatile liquid. The non-volatile liquid is heated by heat in the nuclear reactor container vessel or reaction heat of the fluid in the nuclear reactor container vessel. Then, the trapping apparatus decomposes and traps the organic iodine. The organic iodine trapping method includes heating a non-volatile liquid capable of decomposing organic iodine by heat in the nuclear reactor container vessel or reaction heat of fluid in the nuclear reactor container vessel; making the fluid containing organic iodine pass through the heated non-volatile liquid; and decomposing and trapping the organic iodine in the non-volatile liquid.

[Problem] Provided is an atomic power plant which can be applied to reactors including existing reactors through a simple method and in which a pressure in a primary containment vessel can be restrained from excessively rising in a case where a steam leakage from an exhaust pipe of a stream safety relief valve occurs.

[Solution] There are provided a PCV 1, an RPV 3, a main stream line 4, two SRVs 6, an S/P 8, an SRV exhaust pipe 9 which is connected to a quencher 10, a temperature measuring instrument 12 which measures a temperature inside the quencher 10, an SRV controller 13 which controls opening and closing of the SRVs 6. After a lapse of predetermined time from when the SRV 6 is opened, in a case where it is determined that a temperature detected by the temperature measuring instrument 12 is equal to or smaller than a predetermined threshold value, the SRV controller 13 causes the SRV 6 to which the temperature measuring instrument 12 detecting the temperature leads, to be closed and to be prohibited from being opened.

[Problem] Provided is an atomic power plant which can be applied to reactors including existing reactors through a simple method and in which a pressure in a primary containment vessel can be restrained from excessively rising in a case where a steam leakage from an exhaust pipe of a stream safety relief valve occurs.

[Solution] There are provided a PCV 1, an RPV 3, a main stream line 4, two SRVs 6, an S/P 8, an SRV exhaust pipe 9 which is connected to a quencher 10, a temperature measuring instrument 12 which measures a temperature inside the quencher 10, an SRV controller 13 which controls opening and closing of the SRVs 6. After a lapse of predetermined time from when the SRV 6 is opened, in a case where it is determined that a temperature detected by the temperature measuring instrument 12 is equal to or smaller than a predetermined threshold value, the SRV controller 13 causes the SRV 6 to which the temperature measuring instrument 12 detecting the temperature leads, to be closed and to be prohibited from being opened.

A containment vessel has an inner shell covering a reactor pressure vessel and an outer shell forming an outer well which is a gas-tight space covering the horizontal outer periphery of the inner shell. The inner shell has a first cylindrical side wall surrounding the horizontal periphery of the reactor pressure vessel, a containment vessel head which covers the upper part of the reactor pressure vessel, and a first top slab connecting in a gas-tight manner the periphery of the containment vessel head and the upper end of the first cylindrical side wall. The outer shell has a second cylindrical side wall surrounding the outer periphery of the first cylindrical side wall, and also has a second to slab connecting in a gas-tight manner the vicinity of the upper end of the second cylindrical side wall and the first cylindrical side wall.