An example for continuous removal of fission products from a molten-salt fueled nuclear reactor enclosed in a reactor containment may include separating actinides from other fission products flowing out of the reactor, returning the separated actinides back to the reactor to be consumed, and removing the other fission products out of the containment while the reactor is operating. In various embodiments, the reactor can be a critical reactor, a subcritical (e.g., accelerator-drive) reactor, or another type of reactor.

A neutron absorber apparatus for use in restoring reactivity control to a nuclear fuel rack. The apparatus comprises an elongated tubular insert assembly configured for insertion in a storage cell of the rack. First and second absorber plates, each formed of a boron-containing material, are coupled together by upper and lower stiffening bands at the insert extremities and form a longitudinally-extending cavity configured for receiving a fuel assembly. The absorber plates and stiffening bands may have a rectilinear cross sectional configuration in one embodiment. At least one elastically deformable locking protrusion mounted proximate to the lower end of the absorber plates lockingly engages an available lower edge disposed in the cell sidewall above its bottom end. This fixes the tubular insert axially in the cell, thereby preventing its withdrawal after installing the insert. In one embodiment, the edge may be the bottom of existing absorber sheathing in the cell.

An apparatus for treating waste of a nuclear reactor pressure vessel includes: a suction unit inserted into the nuclear reactor pressure vessel through a plurality of through-pipes passing through a lower portion of the nuclear reactor pressure vessel to suck waste inside the nuclear reactor pressure vessel; a waste treatment part connected to the suction unit to treat the waste; and a lower collection part connected to the waste treatment part to be positioned under the nuclear reactor pressure vessel with the suction unit therebetween.

Fuel assembly for a nuclear reactor comprising a housing of longitudinal axis (X) having a central section containing nuclear-fuel pins and an upper section, forming a portion of the head of the assembly, containing a upper neutron shielding device (NSD) including neutron absorbers and means for reversibly interlocking with the housing and a moveable weight forming the head of the NSD, which is mounted so as to be able to move translationally relative to the rest of the NSD over a given path, said interlocking means being configured so that the NSD and the housing can be interlocked and uninterlocked by moving the moveable weight along the longitudinal axis by means of a grapple for extraction of the NSD, the claws of this grapple engaging with the moveable weight and the rest of the NSD being in downward longitudinal abutment in the interior of the housing.

A method for calculating a PCI margin associated with a loading pattern of a nuclear reactor including a core into which fuel assemblies are loaded according to the loading pattern is implemented by an electronic system. The fuel assemblies include fuel rods each including fuel pellets of nuclear fuel and a cladding surrounding the pellets. This method includes calculating a reference principal PCI margin for a reference loading pattern of the fuel assemblies in the core; calculating a reference secondary PCI margin for the reference pattern; calculating a modified secondary PCI margin for a modified loading pattern of the fuel assemblies in the core, and calculating a modified principal PCI margin for the modified pattern, depending on a comparison of the modified secondary PCI margin with the reference secondary PCI margin.

A system for servicing a nuclear reactor module comprises a crane operable to attach to the nuclear reactor module, wherein the crane includes provisions for routing signals from one or more sensors of the nuclear reactor module to one or more sensor receivers.

A method for restraining a sleeve lining a tube passing through a nuclear reactor pressure vessel is provided. The method includes attaching in situ a radial protrusion on an external surface of the sleeve; and attaching a collar to an end of the tube and coupling the radial protrusion with the collar to retain the thermal sleeve in position.

Proposed is a fixing device for use to handle a spent nuclear fuel assembly and a method for installing same, capable of improving structural reliability of the spent nuclear fuel assembly, the fixing device including: a housing (100) provided with a plurality of free end portions (110), stopper protrusions (120), a first male thread (131), and a female thread (132); a rod member (200) having a length longer than the housing (100), the rod member being provided at a tip end thereof with a pressurization protrusion (210) having an outer diameter larger than an inner diameter of the free end portions, and provided with a second male thread screw-assembled with the female thread (132), thereby being screw-assembled with the housing (100); and fixing members (310 and 320) to fix the housing (100) to the nuclear fuel assembly by being screw-assembled with the first male thread of the housing (100).

Proposed is a fixing device for use to handle a spent nuclear fuel assembly and a method for installing same, capable of improving structural reliability of the spent nuclear fuel assembly, the fixing device including: a housing (100) provided with a plurality of free end portions (110), stopper protrusions (120), a first male thread (131), and a female thread (132); a rod member (200) having a length longer than the housing (100), the rod member being provided at a tip end thereof with a pressurization protrusion (210) having an outer diameter larger than an inner diameter of the free end portions, and provided with a second male thread screw-assembled with the female thread (132), thereby being screw-assembled with the housing (100); and fixing members (310 and 320) to fix the housing (100) to the nuclear fuel assembly by being screw-assembled with the first male thread of the housing (100).

A method of loading fuel in multiple reactor cores associated with a plurality of fuel cycles. The method includes, in a first fuel cycle, loading a first reactor core with a first fuel assembly selected from a first batch of fuel, loading the first reactor core with a first partially spent fuel assembly from a second batch of fuel, loading a second reactor core with a second fuel assembly from the first batch of fuel, and loading the second reactor core with a second partially spent fuel assembly from the second batch of fuel. In a second fuel cycle, which is performed after a completion of the first fuel cycle, the method includes loading the second reactor core with a fresh fuel assembly, and loading the second reactor core with the first fuel assembly from the first batch of fuel.