A reactor core includes an inner core region that extends in a vertical direction, and has a plurality of first fuel pins accommodating an inner core fuel; an outer core region that extends in the vertical direction, is arranged to surround the inner core region from an outer peripheral side, and has a plurality of second fuel pins accommodating an outer core fuel; and a sodium plenum provided above the inner core region and the outer core region, in which a dimension of the outer core fuel in the vertical direction is larger than a dimension of the inner core fuel in the vertical direction, and the position of a center of the outer core fuel in the vertical direction is higher than the position of a center of the inner core fuel in the vertical direction.

A modular, nuclear waste conversion reactor that continuously produces usable energy while converting U-238 and/or other fertile waste materials to fissionable nuclides. The reactor has a highly uniform, self-controlled, core (2) with a decades-long life and does not require reactivity control mechanisms within the boundary of the active core during operation to retain adequate safety. The exemplary embodiment employs high-temperature helium coolant, a dual-segment (22) initial annular critical core, carbide fuel, a fission product gas collection system, ceramic cladding and structural internals to create a modular reactor design that economically produces energy over multiple generations of reactor cores with only minimum addition of fertile material from one generation to the next.

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel is provided. The heterogeneous reactor core comprises at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; and at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel; wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles. The seed fuel channel region and the blanket fuel channel region may be set out in a checkerboard pattern or an annular pattern within the heterogeneous reactor core. Fuel bundles for the core are also provided.

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel is provided. The heterogeneous reactor core comprises at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; and at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel; wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles. The seed fuel channel region and the blanket fuel channel region may be set out in a checkerboard pattern or an annular pattern within the heterogeneous reactor core. Fuel bundles for the core are also provided.

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel is provided. The heterogeneous reactor core comprises at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; and at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel; wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles. The seed fuel channel region and the blanket fuel channel region may be set out in a checkerboard pattern or an annular pattern within the heterogeneous reactor core. Fuel bundles for the core are also provided.

The invention provides a core of a fast reactor including a sodium plenum installed above a core fuel, which is capable of reliably reducing a void reactivity, and an operation method thereof. The core of a fast reactor including the sodium plenum installed above the core fuel is characterized in that a tip of a primary control rod is inserted into a core fuel region, and a tip of a backup control rod is arranged above an upper end of the core fuel region for operation.

There is provided a core of a fast reactor including: a core fuel region in which core fuel assemblies loading a metal fuel are arranged on a central region in a radial direction of the core; an inner blanket fuel region in which blanket fuel assemblies loading another metal fuel are circumferentially arranged on an inner portion of the core fuel region; and an outer peripheral blanket fuel region in which the blanket fuel assemblies are circumferentially arranged on an outer periphery of the core fuel region, wherein the metal fuel is formed of a UPuZr alloy or an alloy of U, Pu, TRU other than Pu, and Zr, the other metal fuel is formed of an alloy of U and Zr, and the Zr content of the other metal fuel is lower than the Zr content of the metal fuel.

There is provided a core of a fast reactor including: a core fuel region in which core fuel assemblies loading a metal fuel are arranged on a central region in a radial direction of the core; an inner blanket fuel region in which blanket fuel assemblies loading another metal fuel are circumferentially arranged on an inner portion of the core fuel region; and an outer peripheral blanket fuel region in which the blanket fuel assemblies are circumferentially arranged on an outer periphery of the core fuel region, wherein the metal fuel is formed of a UPuZr alloy or an alloy of U, Pu, TRU other than Pu, and Zr, the other metal fuel is formed of an alloy of U and Zr, and the Zr content of the other metal fuel is lower than the Zr content of the metal fuel.

A core of a fast reactor including a sodium plenum installed above a core fuel, which is capable of reliably reducing a void reactivity, and an operation method thereof are provided. The core of a fast reactor including the sodium plenum installed above the core fuel is characterized in that a tip of a primary control rod is inserted into a core fuel region, and a tip of a backup control rod is arranged above an upper end of the core fuel region for operation.

Disclosed herein are a molten salt reactor and a passive fuel injection method therefor, wherein the molten salt reactor includes an active core part and a blanket part, wherein the active core part is disposed to define a liquid-liquid interface with an upper portion of the blanket part having a liquid metal phase, and a fissile fuel is passively supplied from a lower blanket part to an upper active core part through the liquid-liquid interface, and a fertile fuel is passively supplied from the upper active core to the lower blanket part, and a passive fuel injection method using the same.