Jet pump clamps and methods for use in a nuclear reactor jet pump

A repaired jet pump assembly in a nuclear reactor, the assembly comprising:

• a riser pipe configured to convey a fluid coolant vertically upward;
• two inlet mixers each at a different side of the riser pipe from one another and configured to convey the fluid coolant vertically downward;
• a restrainer bracket connected to the riser pipe and one of the two inlet mixers;
• and
• a clamp on the riser pipe and passing through the restrainer bracket to prevent relative movement of the riser pipe and the restrainer bracket, wherein the clamp compresses the riser pipe in the vertical direction, wherein the clamp seats into two grooves in an outer surface of the riser pipe, and wherein the clamp compresses the riser pipe by vertically compressing the two grooves together.

A method of preparing a jet pump assembly having a restrainer bracket for use in a nuclear reactor with a jet pump clamp, the method comprising:

• forming at least one groove in an outer surface of a riser pipe of the jet pump assembly above a restrainer bracket-riser pipe junction point;
• forming at least one groove in the outer surface of the riser pipe below the restrainer bracket-riser pipe junction point;
• and
• forming at least one hole passing vertically through the restrainer bracket of the jet pump assembly.