An apparatus for reinforcing a jet pump riser includes: an elbow upper clamp for covering a riser elbow coupled to a thermal sleeve from an upper side thereof; an elbow lower clamping member for clamping the riser elbow from a lower side thereof; an elbow vertical portion clamping member for covering a vertical portion of the riser elbow; and an elbow horizontal portion clamping member for covering a horizontal portion of the riser elbow. These members are disposed in different orientations with respect to the elbow upper clamp so as to fix the thermal sleeve, the riser elbow and the riser pipe.

Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.

Flow induced vibration (FIV) at the slip joint between a nuclear reactor jet pump mixer and diffuser is suppressed without installing additional parts or altering the jet pump construction. The disclosed method determines a relationship between reactor operating conditions that trigger FIV and the magnitude of a mixer/diffuser transverse contact load. A mathematical analysis on a representative jet pump configuration determines the quantitative relationship between mixer/diffuser cold positions and their positions when the reactor is operating. Thus, a prediction can be made as to whether an installed jet pump will experience FIV, and the mixer and diffuser can be positioned by a mixer adjustment tool when the reactor is cold to provide the necessary operational transverse contact load. Alternatively, a contact load measuring tool directly measures the magnitude and direction of the cold mixer/diffuser transverse contact load to determine if FIV will be suppressed when the reactor is operating.

Flow induced vibration (FIV) at the slip joint between a nuclear reactor jet pump mixer and diffuser is suppressed without installing additional parts or altering the jet pump construction. The disclosed method determines a relationship between reactor operating conditions that trigger FIV and the magnitude of a mixer/diffuser transverse contact load. A mathematical analysis on a representative jet pump configuration determines the quantitative relationship between mixer/diffuser cold positions and their positions when the reactor is operating. Thus, a prediction can be made as to whether an installed jet pump will experience FIV, and the mixer and diffuser can be positioned by a mixer adjustment tool when the reactor is cold to provide the necessary operational transverse contact load. Alternatively, a contact load measuring tool directly measures the magnitude and direction of the cold mixer/diffuser transverse contact load to determine if FIV will be suppressed when the reactor is operating.

A jet pump slip joint repair assembly includes at least one clamp and a bushing configured to be inserted in a bore of a diffuser and to surround a portion of an inlet mixer. The clamp includes a gripping surface and a gripping collar. The bushing includes a generally cylindrical sidewall, the sidewall configured to surround the portion of the inlet mixer, a grooved flange on an upper surface of the sidewall, at least one cutout between adjacent portions of the grooved flange, and a groove on an inner, bottom surface of the sidewall. The assembly also includes a seal in the groove. The seal is flexible and formed of a metallic material. The seal is configured to be compressed when the at least one clamp engages the bushing.

A method of repairing a slip joint on a jet pump assembly between an inlet mixer and a diffuser, with the diffuser having an opening that receives the inlet mixer with a given spacing between an outside diameter of the inlet mixer and an inside diameter of the opening in the diffuser forming an annulus whose spacing is a product of manufacture and vibration wear. The method comprises the steps of remotely accessing the annulus and narrowing a radial dimension of the annulus.

A method of repairing a slip joint on a jet pump assembly between an inlet mixer and a diffuser, with the diffuser having an opening that receives the inlet mixer with a given spacing between an outside diameter of the inlet mixer and an inside diameter of the opening in the diffuser forming an annulus whose spacing is a product of manufacture and vibration wear. The method comprises the steps of remotely accessing the annulus and narrowing a radial dimension of the annulus.

A sealing device for a jet pump of a boiling water reactor is provided. The jet pump includes an inlet mixer and a diffuser receiving the inlet mixer at a slip joint such that an outer circumferential surface of the inlet mixer is received in an inner circumferential surface of the diffuser at the slip joint. The diffuser includes a plurality of guiding fins, each guiding fin including a radially inner surface, a radially outer surface and lateral surfaces extending radially between the inner and outer surfaces. The sealing device includes a seal configured for sealingly contacting the outer circumferential surface of the inlet mixer and a collar configured for holding the seal against the outer circumferential surface of the inlet mixer. The collar includes portions configured for being received radially between the radially inner surfaces of the guiding fins and the outer circumferential surface of the inlet mixer. The sealing device further includes a clamp configured for contacting the radially outer surfaces of the guiding fins to axially clamp the guiding fins. A method of mounting a sealing device onto a slip joint of a jet pump of a boiling water reactor is also provided.

A sealing device for a jet pump of a boiling water reactor is provided. The jet pump includes an inlet mixer and a diffuser receiving the inlet mixer at a slip joint such that an outer circumferential surface of the inlet mixer is received in an inner circumferential surface of the diffuser at the slip joint. The diffuser includes a plurality of guiding fins, each guiding fin including a radially inner surface, a radially outer surface and lateral surfaces extending radially between the inner and outer surfaces. The sealing device includes a seal configured for sealingly contacting the outer circumferential surface of the inlet mixer and a collar configured for holding the seal against the outer circumferential surface of the inlet mixer. The collar includes portions configured for being received radially between the radially inner surfaces of the guiding fins and the outer circumferential surface of the inlet mixer. The sealing device further includes a clamp configured for contacting the radially outer surfaces of the guiding fins to axially clamp the guiding fins. A method of mounting a sealing device onto a slip joint of a jet pump of a boiling water reactor is also provided.

Flow induced vibration (FIV) at the slip joint between a nuclear reactor jet pump mixer and diffuser is suppressed without installing additional parts or altering the jet pump construction. The disclosed method determines a relationship between reactor operating conditions that trigger FIV and the magnitude of a mixer/diffuser transverse contact load. A mathematical analysis on a representative jet pump configuration determines the quantitative relationship between mixer/diffuser cold positions and their positions when the reactor is operating. Thus, a prediction can be made as to whether an installed jet pump will experience FIV, and the mixer and diffuser can be positioned by a mixer adjustment tool when the reactor is cold to provide the necessary operational transverse contact load. Alternatively, a contact load measuring tool directly measures the magnitude and direction of the cold mixer/diffuser transverse contact load to determine if FIV will be suppressed when the reactor is operating.