Abstract: Example embodiment fuel bundles use multiple types of spacers within the same fuel bundle. The type for each spacer location may be determined based on the axial position of the spacer, the characteristics of the spacer type, and the location and coolant characteristics for the particular example fuel bundle including the spacers. Historic performance data for the particular bundle location, predictive modeling, etc. may be used to determine what spacer types at which locations result in the best operating conditions and margins for example fuel bundles.

Abstract: Control rod guide tubes for a nuclear reactor having a body with an axial length that defines a lower end portion and an upper end portion and a cavity within a substantial length of the body. Orifices are included at the upper and lower end portions of the body. A control rod chamber is located within the cavity and is configured for receiving a control rod. A plurality of ports is coupled to the cavity and is positioned at a substantial length from the upper end portion of the body. Also included are at least two flow channels within the cavity that extend a substantial portion of the axial length of the body. Each flow channel is fluidly coupled to one or more of the ports for receiving fluid flow from outside the body and an outlet proximate to the upper end portion of the body for providing the received fluid flow.

Abstract: A fuel support for a nuclear reactor may include: a plurality of fuel support apertures, each fuel support aperture dimensioned for receiving a lower tie plate of a fuel assembly; and a plurality of lumens, each lumen being coupled to a different fuel support aperture. At least one lumen may be configured for attenuating a fluid flow differently than the fluid flow in at least one other of the lumen.

Abstract: Example embodiment fuel bundles use multiple types of spacers within the same fuel bundle. The type for each spacer location may be determined based on the axial position of the spacer, the characteristics of the spacer type, and the location and coolant characteristics for the particular example fuel bundle including the spacers. Historic performance data for the particular bundle location, predictive modeling, etc. may be used to determine what spacer types at which locations result in the best operating conditions and margins for example fuel bundles.

Abstract: Control rod guide tubes for a nuclear reactor having a body with an axial length that defines a lower end portion and an upper end portion and a cavity within a substantial length of the body. Orifices are included at the upper and lower end portions of the body. A control rod chamber is located within the cavity and is configured for receiving a control rod. A plurality of ports is coupled to the cavity and is positioned at a substantial length from the upper end portion of the body. Also included are at least two flow channels within the cavity that extend a substantial portion of the axial length of the body. Each flow channel is fluidly coupled to one or more of the ports for receiving fluid flow from outside the body and an outlet proximate to the upper end portion of the body for providing the received fluid flow.

Abstract: Control rod guide tubes for a nuclear reactor having a body with an axial length that defines a lower end portion and an upper end portion and a cavity within a substantial length of the body. Orifices are included at the upper and lower end portions of the body. A control rod chamber is located within the cavity and is configured for receiving a control rod. A plurality of ports is coupled to the cavity and is positioned at a substantial length from the upper end portion of the body. Also included are at least two flow channels within the cavity that extend a substantial portion of the axial length of the body. Each flow channel is fluidly coupled to one or more of the ports for receiving fluid flow from outside the body and an outlet proximate to the upper end portion of the body for providing the received fluid flow.

Abstract: A fuel support for a nuclear reactor may include: a plurality of fuel support apertures, each fuel support aperture dimensioned for receiving a lower tie plate of a fuel assembly; and a plurality of lumens, each lumen being coupled to a different fuel support aperture. At least one lumen may be configured for attenuating a fluid flow differently than the fluid flow in at least one other of the lumen.

Abstract: Fuel supports for a nuclear reactor and methods of modifying fluid flow in a reactor using a fuel support. The fuel supports include a plurality of lumens and a plurality of fuel support apertures with each fuel support aperture being dimensioned for receiving a lower tie plate of a fuel assembly. Each lumen is fluidly coupled to a different fuel support aperture. At least one lumen is configured for attenuating a fluid flow differently than the fluid flow in at least one other of the lumen.

Abstract: Fuel supports for a nuclear reactor and methods of modifying fluid flow in a reactor using a fuel support. The fuel supports include a plurality of lumens and a plurality of fuel support apertures with each fuel support aperture being dimensioned for receiving a lower tie plate of a fuel assembly. Each lumen is fluidly coupled to a different fuel support aperture. At least one lumen is configured for attenuating a fluid flow differently than the fluid flow in at least one other of the lumen.

Abstract: Control rod guide tubes for a nuclear reactor having a body with an axial length that defines a lower end portion and an upper end portion and a cavity within a substantial length of the body. Orifices are included at the upper and lower end portions of the body. A control rod chamber is located within the cavity and is configured for receiving a control rod. A plurality of ports is coupled to the cavity and is positioned at a substantial length from the upper end portion of the body. Also included are at least two flow channels within the cavity that extend a substantial portion of the axial length of the body. Each flow channel is fluidly coupled to one or more of the ports for receiving fluid flow from outside the body and an outlet proximate to the upper end portion of the body for providing the received fluid flow.