A channel baffle structure comprises a pipe, a swing check plate and a driving apparatus, wherein the main part of the swing check plate is located inside the pipe, and the driving apparatus is disposed outside the pipe. A connection structure is used for connecting the driving apparatus and the swing check plate. The check plate can be opened and closed passively by gravity and fluid pressure, but can also be actively opened and closed by the driving apparatus, such that requirements for multiple operating conditions of the channel can be satisfied.

A channel baffle structure comprises a pipe, a swing check plate and a driving apparatus, wherein the main part of the swing check plate is located inside the pipe, and the driving apparatus is disposed outside the pipe. A connection structure is used for connecting the driving apparatus and the swing check plate. The check plate can be opened and closed passively by gravity and fluid pressure, but can also be actively opened and closed by the driving apparatus, such that requirements for multiple operating conditions of the channel can be satisfied.

A control rod drive system and an inspection method of the control rod drive system capable of performing inspection safely and effectively. A control rod drive system controlling operation by supplying a hydraulic pressure to control rod drive mechanisms. A plurality of first hydraulic control units supply the hydraulic pressure to corresponding control rod drive mechanisms and a second hydraulic control unit supplies the hydraulic pressure to corresponding control rod drive mechanisms of the first hydraulic control unit as an inspection target instead of the first hydraulic control unit.

A control rod drive system and an inspection method of the control rod drive system capable of performing inspection safely and effectively. A control rod drive system controlling operation by supplying a hydraulic pressure to control rod drive mechanisms. A plurality of first hydraulic control units supply the hydraulic pressure to corresponding control rod drive mechanisms and a second hydraulic control unit supplies the hydraulic pressure to corresponding control rod drive mechanisms of the first hydraulic control unit as an inspection target instead of the first hydraulic control unit.

Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate the magnetic fields across a full stroke length of the control element in the reactor. A closed coolant loop may cool the induction coils, which may be in a vacuum outside the isolation barrier. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Methods of operation include selectively energizing or de-energizing induction coils to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through secured magnetic elements subject to magnetic fields. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. A motor may spin a linear screw to move the induction coils on a vertical travel nut. A control rod assembly may house the magnetic elements and directly, removably join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the induction coils with a linear screw to drive the control element to desired insertion points, including full insertion by gravity following de-energization. No direct connection may penetrate the isolation barrier.

A rotation apparatus is usable with a control drum in a nuclear environment. The control drum is situated on a shaft that is rotatable about a horizontal axis of rotation, and the control drum includes an absorber portion and a reflector portion. The rotation apparatus includes a rotation mechanism that is structured to apply to the shaft in an operational position a force that biases the shaft to rotate toward a shutdown position, with the force being resisted by a motor to retain the shaft in the operational position when the motor is powered. The force is not resisted when the motor is unpowered. The rotation apparatus further includes a rotation management system that controls the rotation of the shaft

A rotation apparatus is usable with a control drum in a nuclear environment. The control drum is situated on a shaft that is rotatable about a horizontal axis of rotation, and the control drum includes an absorber portion and a reflector portion. The rotation apparatus includes a rotation mechanism that is structured to apply to the shaft in an operational position a force that biases the shaft to rotate toward a shutdown position, with the force being resisted by a motor to retain the shaft in the operational position when the motor is powered. The force is not resisted when the motor is unpowered. The rotation apparatus further includes a rotation management system that controls the rotation of the shaft

Control rod drives include linearly-moveable control elements inside an isolation barrier. Control rod drives move the control element through a motor and rotor powering a linear screw internal to an isolation barrier. Induction coils may generate magnetic fields and be moveable across a full stroke length of the control element in the reactor. The magnetic fields hold closed a releasable latch to disconnect the control elements from the linear drives. A control rod assembly may join to the control element. The control rod assembly may lock with magnetic overtravel latches inside the isolation barrier to maintain an overtravel position. Overtravel release coils outside the isolation barrier may release the latches to leave the overtravel position. Operation includes moving the magnetic fields and releasable latch together on opposite sides of an isolation barrier to drive the control element to desired insertion points, including full insertion by gravity following de-energization.

The present invention relates to a nuclear reactor, more precisely a passive safety device applicable to a thermal neutron reactor and a nuclear fuel assembly equipped with the same. The nuclear fuel assembly for a thermal neutron reactor of the present invention includes multiple fuel rods; multiple guide thimbles arranged between the fuel rods; and a passive safety device including neutron absorber parts which are inserted in one or more guide thimbles.