DEVICE AND METHOD FOR FIXING A REACTOR METERING PIPE

• US 20090032650A1
• Filed: 07/03/2008
• Published: 02/05/2009
• Est. Priority Date: 07/06/2007
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Watanabe, Yuusuke, Kasai, Shigeru, Hagiwara, Tsuyoshi, Mori, Hajime, Saito, Noboru, Watanabe, Masanobu, Okuda, Ken, Saiki, Kiyofumi, MAEHARA, Takeshi, Iwasa, Hideshi, Kinugasa, Kunihiko
• Granted Patent: US 8,608,121 B2
• Time in Patent Office: Days
• US Class Current: 248/65
• CPC Class Codes: F16L 3/02 partly surrounding the pipes, cables or protective tubing bands or chains F16L3/14
• 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: G21C 17/032 Reactor-coolant flow measuring or monitoring measuring volume or mass flow in general G01F
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A reactor metering pipe fixing device fixes a reactor metering pipe disposed in a reactor to a cylindrical outer surface of a jet pump diffuser and reduces stress that may be induced in a weld zone in the reactor metering pipe. An outer holding member 41 is held on the cylindrical outer surface 18a of a jet pump diffuser 18 by a C-shaped holding member 30. The reactor metering pipe 19 is clamped from radial directions by the outer holding member 41 and inner holding members 42 and 43. Wedges 44 and 45 are wedged into a gap between the cylindrical outer surface 18a and the inner holding member 42 and a gap between the cylindrical outer surface 18a and the inner holding member 43 to fix the reactor metering pipe 19 firmly to the cylindrical outer surface 18a.

Claims

1. A reactor metering pipe fixing device for fixedly holding a vertical metering pipe on the cylindrical outer surface of a jet pump diffuser installed in the reactor pressure vessel of a boiling-water reactor so as to be spaced from the cylindrical outer surface by holding the metering pipe from the outer and the inner side with respect to a radial direction, said reactor metering pipe fixing device comprising:

an outer holding member brought into contact with the metering pipe from the outer side of the metering pipe with respect to a radial direction;

inner holding members brought into contact with the metering pipe from the inner side of the metering pipe with respect to a radial direction;

wedges each wedged into a space between the inner holding member and the cylindrical outer surface;

a first holding means for holding the outer holding member on the cylindrical outer surface;

a second holding means holding either of the inner holding members and the wedges so as to be movable in the radial direction relative to the outer holding member; and

vertically moving means for vertically moving the other of the inner holding members and the wedges relative to the outer holding member, held by the other of the inner holding members and the wedges, and the outer holding member or either of the inner holding members and the wedges.

2. The reactor metering pipe fixing device according to claim 1, wherein the inner holding members the wedges, the second support means, and the vertically moving means are disposed at the upper and the lower end of the outer holding member, respectively, to fix two vertically spaced parts of the metering pipe to the cylindrical outer surface.

3. The reactor metering pipe fixing device according to claim 1, wherein the outer holding member is detachably attached to the first holding means.

4. The reactor metering pipe fixing device according to claim 3 further comprising an outer holding member moving means for radially moving the outer holding member relative to the cylindrical outer surface, supported on the first holding means.

5. The reactor metering pipe fixing device according to claim 1, wherein the outer holding member is formed integrally with the first holding means.

6. The reactor metering pipe fixing device according to claim 1, wherein the outer holding member has a positioning part that is engaged with a connecting member for connecting the metering pipe to the cylindrical outer surface to position the outer holding member with respect to a vertical direction.

7. The reactor metering pipe fixing device according to claim 6, wherein the inner holding member, the wedge, the second support means, and the vertically moving means are disposed directly below the positioning part of the outer holding member.

8. The reactor metering pipe fixing device according to claim 1, wherein the wedge is provided in its contact surface to be in contact with the cylindrical outer surface with a recess capable of being engaged with a stump-shaped protrusion formed by cutting the connecting part for connecting the metering pipe to the cylindrical outer surface for repairing and remaining on the cylindrical outer surface to position the wedge with respect to a vertical direction.

9. The reactor metering pipe fixing device according to claim 1, wherein the vertically moving means are a screw vertically screwed in either of one of the inner holding member and one of the wedges, and a screw screwed in either of the other inner holding member and the other wedge or the outer holding member.

10. The reactor metering pipe fixing device according to claim 9, wherein the screw on the side of the upper end of the outer holding member is disposed on one side of the metering pipe with respect to a circumferential direction on the cylindrical surface, and the screw on the side of the lower end of the outer holding member is disposed on the other side of the metering pipe with respect to a circumferential direction on the cylindrical outer surface.

11. A reactor metering pipe fixing method of fixing the metering pipe to the cylindrical surface by using the reactor metering pipe fixing device in claim 1, characterized in fixing plural vertically spaced parts of the metering pipe to the cylindrical outer surface.

12. A reactor metering pipe fixing device capable of reducing stress that may be induced by fluid vibrations in a welded joint of a metering pipe and a connecting member connecting the metering pipe to the cylindrical outer surface of a jet pump diffuser installed in the reactor pressure vessel of a boiling-water reactor, said reactor metering pipe fixing device comprising:

a C-shaped holding member detachably mounted on the jet pump diffuser;

an assembly placed on the C-shaped holding member in contact with the metering pipe and the cylindrical outer surface of the jet pump diffuser; and

inner holding members, wedges for fixing the metering pipe, and screws for moving the wedges, which are included in the assembly.

13. The reactor metering pipe fixing device according to claim 12, wherein the C-shaped molding member and the assembly apply pressure to one side of the cylindrical outer surface of the jet pump diffuser, the other opposite side of the cylindrical outer surface, and the connecting the connecting member by the agency of the inner holding members and the wedges.

14. The reactor metering pipe fixing device according to claim 12, wherein the C-shaped holding member has the shape of a circular arc surrounding substantially half the cylindrical outer surface;

pressing members are disposed on one circumferential end of the C-shaped holding member; and

the pressing members are combined with a wedge and a screw for pressing the pressing members against the cylindrical outer surface.

15. The reactor metering pipe fixing device according to claim 12, wherein the assembly includes inner holding members for fastening the reactor metering pipe, wedges for fastening the diffuser, and screws for moving the wedges;

and the wedges are guided by guide pins included in the assembly for movement in predetermined directions.

16. The reactor metering pipe fixing device according to claim 12, wherein the screws are locked by lock sleeves or toothed lock washers, respectively.