A getter element includes a getter material reactive with a fission product contained within a stream of liquid and/or gas exiting a fuel assembly of a nuclear reactor. At least one transmission pathway passes through the getter element that is sufficiently sized to maintain a flow of the input stream through the getter element at above a selected flow level. At least one transmission pathway includes a reaction surface area sufficient to uptake a pre-identified quantity of the fission product.

A nuclear reactor includes a reactor container, a reactor core, a control drum assembly, a hot channel, a heat exchanger and a main pump. The reactor container contains a coolant; the reactor core is arranged at a lower middle part of the reactor container; the control drum assembly is arranged on an outer periphery of the reactor core, and includes control drums arranged at intervals along a peripheral direction of the reactor core; the hot channel is arranged in the reactor container and located above the reactor core. The hot channel has a bottom hermetically connected to the control drum assembly and a top hermetically connected to an inner top surface of the reactor container. The hot channel has a hot pool passage for the coolant to pass through. The heat exchanger is arranged in the reactor container and located on an outer periphery of the hot channel.

An insertable flux thimble interface for use in a bottom nozzle of a fuel assembly in a nuclear reactor (i.e., a bottom nozzle insert) is disclosed herein. In various aspects, the bottom nozzle insert has properties that are different from traditional bottom nozzle flux thimble interfaces. The properties of the bottom nozzle insert may mitigate wear phenomena observed on the flux thimble. For example, the bottom nozzle insert may be constructed from material that is different from the material of the bottom nozzle. In some aspects, the bottom nozzle insert is constructed from material that has a hardness that is less than the hardness the bottom nozzle material. In other aspects, the bottom nozzle insert is constructed from a material that has a hardness that is less than the hardness of the flux thimble material.

A cladding tube, a fuel rod and a fuel assembly are disclosed. The cladding tube comprises a tubular base component having an outer surface and an inner surface defining an inner space of the cladding tube housing a pile of fuel pellets. The tubular base component is made of a Zr-based alloy. A coating is applied onto the outer surface for protecting the tubular base component from mechanical wear, oxidation and hydriding. The Zr-based alloy has the following composition: Zr=balance, Al=0-2 wt %, Ti=0-20 wt %, Sn=0-6 wt %, Fe=0-0.4 wt %, Nb=0-0.4 wt %, O=200-1800 wtppm, C=0-200 wtppm, Si=0-200 wtppm, and S=0-200 wtppm. The total amount of Al+Ti+Sn>2.5 wt % and ≤28 wt %.

A cladding tube, a fuel rod and a fuel assembly are disclosed. The cladding tube comprises a tubular base component having an outer surface and an inner surface defining an inner space of the cladding tube housing a pile of fuel pellets. The tubular base component is made of a Zr-based alloy. A coating is applied onto the outer surface for protecting the tubular base component from mechanical wear, oxidation and hydriding. The Zr-based alloy has the following composition: Zr=balance, Al=0-2 wt %, Ti=0-20 wt %, Sn=0-6 wt %, Fe=0-0.4 wt %, Nb=0-0.4 wt %, O=200-1800 wtppm, C=0-200 wtppm, Si=0-200 wtppm, and S=0-200 wtppm. The total amount of Al+Ti+Sn>2.5 wt % and ≤28 wt %.

One embodiment provides a multi-segment rod that includes a plurality of rod segments. The rod segments are removably mated to each other via mating structures in an axial direction. An irradiation target is disposed within at least one of the rod segments, and at least a portion of at least one mating structure includes one and/or more combinations of neutron absorbing materials.

It is possible to achieve self-support of the fuel assembly without an upper grid plate when the fuel assembly is mounted or replaced, and it is also possible to prevent the fuel assembly from floating during a reactor operation. According to the present invention, the lower portion of the lower tie plate 7 as a part of the fuel assembly 3, which is inserted into the fuel support 9, extends, and a stable member 21 is provided around the extension portion 20, and thereby it is possible to achieve the self-support of the fuel assembly without the upper grid plate. In addition, since an increase in a weight due to extension of the lower portion of the lower tie plate 7 can prevent the floating during the reactor operation, a floating preventing mechanism using the upper grid plate is not necessary. Hence, it is possible to achieve the self-support of the fuel assembly without an upper grid plate when the fuel assembly is mounted or replaced, and it is also possible to prevent the fuel assembly from floating during the reactor operation.

Systems and methods for providing and using molten salt reactors are described. While the systems can include any suitable component, in some cases, they include a graphite reactor core defining an internal space that houses one or more fuel wedges, where each wedge defines one or more fuel channels that extend from a first end to a second end of the wedge. In some cases, one or more of the fuel wedges comprise multiple wedge sections that are coupled together end to end and/or in any other suitable manner. In some cases, one or more alignment pins also extend between two sections of a fuel wedge to align the sections. In some cases, one or more seals are also disposed between two sections of a fuel wedge. Thus, in some cases, the reactor core can be relatively long (e.g., to be a pipeline reactor). Other implementations are also described.

Systems and methods for providing and using molten salt reactors are described. While the systems can include any suitable component, in some cases, they include a graphite reactor core defining an internal space that houses one or more fuel wedges, where each wedge defines one or more fuel channels that extend from a first end to a second end of the wedge. In some cases, one or more of the fuel wedges comprise multiple wedge sections that are coupled together end to end and/or in any other suitable manner. In some cases, one or more alignment pins also extend between two sections of a fuel wedge to align the sections. In some cases, one or more seals are also disposed between two sections of a fuel wedge. Thus, in some cases, the reactor core can be relatively long (e.g., to be a pipeline reactor). Other implementations are also described.

Packaging structures and systems are used for handling components for use in a nuclear reactor. The packaging protects the component during transport and handling and then dissolves in liquid in the nuclear reactor or fuel pool. The packaging need not be removed and may block flow paths or otherwise interfere with operability were it not for its dissolution. The packaging may include shock absorbers in a fuel assembly or a seal on a water rod in the assembly. Mechanical, frictional, or chemical retaining materials may be used to secure the packaging and may also dissolve in the liquid. For a light water reactor, polymers, protein gels, and plastics can all be used where they will dissolve in the water and are otherwise compatible with reactor chemistry and neutronics. Materials with higher temperatures for solubility may be used because they will dissolve when reactor operations commence.