FLOW RESTRICTING SLIP JOINT CLAMPS AND METHODS FOR USE IN A NUCLEAR REACTOR JET PUMP

• US 20200135348A1
• Filed: 10/29/2018
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Ge-Hitachi Nuclear Energy Americas LLC (GE Vernova, Inc.)
• Original Assignee: Ge-Hitachi Nuclear Energy Americas LLC (GE Vernova, Inc.)
• Inventors: Lane, Hampton W., Nelson, Bret E., Schoonmaker, Brandon J., Andre, Lee J., Rooney, Hugo P., Bell, David J.
• Granted Patent: US 11,538,598 B2
• Time in Patent Office: Days
• CPC Class Codes: F04F 5/461 Adjustable nozzles
• CPC Class Codes: F04F 5/463 with provisions for mixing
• CPC Class Codes: F16L 23/0283 the collar being integral with the pipe
• CPC Class Codes: F16L 23/12 specially adapted for particular pipes
• CPC Class Codes: G21C 13/032 Joints between tubes and vessel walls, e.g. taking into account thermal stresses
• CPC Class Codes: G21C 15/25 using jet pumps
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

Clamps can be secured to a slip joint and limit flow through the same by seating on a diffuser axially regardless of wear and damage in the slip joint. An extension from the clamp seats to the inlet mixer. These extensions can be adjusted from outside the clamp to achieve an individual preload or flow limitation through the slip joint. The extension may be an O-ring or other shape. A biasing drive may connect to and move the extension from an outside surface of the clamp. The biasing drive may include a threaded cap in an outer groove that is linked to a plunger via a spring. Clamps are fabricated of materials that maintain their physical properties when exposed to an operating nuclear reactor environment and may be relatively rigid and resilient metals.

Claims

1. A clamp for a slip joint formed by a juncture of a diffuser and inlet mixer in a nuclear reactor, the clamp comprising:

a plurality of moveable clamp arms shaped to seat on a top end of the diffuser and against an outer surface of the inlet mixer;

a joint moveably connecting at least two of the clamp arms to permit movement of the two clamp arms around the inlet mixer; and

an adjustable extension from an inner surface of at least one of the clamp arms configured to move in a transverse direction and directly contact the inlet mixer so as to limit fluid flow past the inlet mixer and out of the slip joint.

2. The clamp of claim 1, wherein the plurality of moveably clamp arms are two annular halves that join to form a continuous annulus around an entire upper and inner perimeter of the diffuser, and wherein the adjustable extension is seated in and moves with an inner surface of only one of the two annular halves.

3. The clamp of claim 2, wherein the joint is a pin allowing rotation of the two annular halves with respect to each other about a single axis with no other relative movement.

4. The clamp of claim 1, further comprising:

a biasing drive connected to and moving the adjustable extension and open to an outside surface of the clamp.

5. The clamp of claim 4, wherein the biasing drive is captured in an outer groove of the outside surface, wherein the outer groove connects to an inner groove housing the adjustable extension in the inner surface.

6. The clamp of claim 5, wherein the biasing drive includes a threaded cap, a spring, and a plunger that drive the adjustable extension.

7. The clamp of claim 6, wherein the outer groove includes threads that mesh with the threaded cap such that the threaded cap moves transversely toward or away from the adjustable extension when rotated in the outer groove, wherein the threaded cap seats to the spring, and wherein the spring seats to the plunger such that the plunger and the threaded cap may move at different transverse rates.

8. The clamp of claim 7, wherein the adjustable extension is an O-ring, and wherein the plunger extends from the outer groove to the inner groove to contact and drive the O-ring.

9. The clamp of claim 1, wherein the adjustable extension is a rigid O-ring captured in a groove in the inner surface.

10. The clamp of claim 1, wherein the O-ring is fabricated entirely of at least one of a stainless steel alloy, a zirconium alloy, and an aluminum alloy.

11. The clamp of claim 1, further comprising:

an axial mount on one of the clamp arms, wherein the axial mount is configured to secure to only an exterior of the diffuser so as to prevent relative movement between the one clamp arm and the diffuser.

12. The clamp of claim 1, wherein the lateral drive includes a leaf spring captured in the one clamp arm, and wherein the adjustable extension is axially below the leaf spring.

13. A clamp for a slip joint formed by a juncture of a diffuser and inlet mixer in a nuclear reactor, the clamp comprising:

at least two opposite clamp arms shaped to fit inside of the diffuser and against the inlet mixer in the slip joint;

a spring configured to bias the inlet mixer in a transverse direction against at least one of the clamp arms without transversely loading the diffuser; and

an O-ring seated in a perimeter of the two opposite clamp arms, wherein the O-ring fills the slip joint, and wherein the O-ring is configured to bias against the inlet mixer separately from the spring biasing the inlet mixer.

14. The clamp of claim 13, wherein the two opposite clamp arms are semi-circular and join to create a continuous annulus, and wherein the O-ring extends around an entire inner surface of the annulus.

15. The clamp of claim 13, further comprising:

a biasing drive connected to and moving the O-ring and open to an outside surface of the clamp.

16. The clamp of claim 15, wherein the biasing drive is captured in an outer groove of the outside surface, wherein the outer groove connects to an inner groove housing the O-ring in an inner surface of the clamp arms.

17. The clamp of claim 16, wherein the biasing drive includes a threaded cap, a spring, and a plunger that drive the O-ring.

18. The clamp of claim 17, wherein the outer groove includes threads that mesh with the threaded cap such that the threaded cap moves transversely toward or away from the O-ring when rotated in the outer groove, wherein the threaded cap seats to the spring, and wherein the spring seats to the plunger such that the plunger and the threaded cap may move at different transverse rates.

19. A method of stabilizing a slip joint between a diffuser and an inlet mixer in a nuclear reactor jet pump assembly, the method comprising:

axially seating a slip joint clamp to an axial top of the diffuser to surround the inlet mixer without axially loading the inlet mixer;

transversely biasing the slip joint clamp against the inlet mixer; and

transversely biasing a flow limiting extension from the slip joint clamp against the inlet mixer.

20. The method of claim 19, wherein the axially seating includes clamping the slip joint clamp to a plurality of guide ears on the diffuser, and wherein the transversely biasing the flow limiting extension includes rotating a biasing drive from an exterior surface of the slip joint clamp to drive the flow limiting extension from an inner surface of the slip joint clamp.

20-1. The method of claim 19, wherein the transversely expanding includes rotating two annular halves about a pin, and wherein the transversely closing includes connecting a bolt between the two annular halves to prevent any further rotation.