Steam generator

Abstract

A steam generator includes: an annular member ( 21 ) that surrounds a U-bent portion ( 18 ) obtained by collectively disposing bent portions of a plurality of heat transfer tubes and is provided between an outer peripheral portion of the U-bent portion ( 18 ) and a tube bundle shroud ( 3 ) surrounding the outer peripheral portion so as to have a predetermined gap with respect to the U-bent portion ( 18 ); a second support member ( 22 ) that is provided between the annular member ( 21 ) and the tube bundle shroud ( 3 ); and a third support member ( 23 ) that is attached to a cylinder portion ( 2 ) accommodating a plurality of heat transfer tubes and supports the second support member ( 22 ).

1 . A steam generator comprising:
 a first support member that surrounds a U-bent portion obtained by collectively disposing bent portions of a plurality of heat transfer tubes and is provided between the U-bent portion and a tube bundle shroud surrounding an outer peripheral portion of the U-bent portion so as to have a predetermined gap with respect to the U-bent portion;   a second support member that is provided between the first support member and the tube bundle shroud; and   a third support member that is attached to a cylinder portion accommodating the plurality of heat transfer tubes and supports the second support member.   
     
     
         2 . The steam generator according to  claim 1 , wherein the first support member includes a regulation member that sandwiches a bridge, connecting a plurality of holding members connecting ends of a plurality of vibration preventing members disposed between the heat transfer tubes in the portion, with a predetermined gap therebetween so as to regulate a movement of the bridge. 
     
     
         3 . The steam generator according to  claim 2 , wherein the regulation member includes an orifice that is formed at a portion facing the bridge. 
     
     
         4 . The steam generator according to  claim 1 , wherein a plurality of the second support members extend radially from the first support member toward the tube bundle shroud and are fixed to the tube bundle shroud, and
 a plurality of the third support members extend radially from the tube bundle shroud and connect the tube bundle shroud and the cylinder portion to each other.   
     
     
         5 . The steam generator according to  claim 1 , wherein a plurality of the first support members are disposed toward a top portion of the U-bent portion. 
     
     
         6 . The steam generator according to  claim 5 , wherein the plurality of second support members overlap each other and the plurality of second members overlap each other between the plurality of the plurality of first support members when viewed from a direction in which the plurality of first support members are arranged. 
     
     
         7 . A steam generator with a U-bent portion obtained by collectively disposing circular-arc portions of upper ends of a plurality of inverse U-shaped heat transfer tubes, the steam generator comprising:
 partition plates that are inserted between the heat transfer tubes of the U-bent portion so as to divide the U-bent portion into a plurality of portions and are supported by a support portion to a cylinder portion accommodating the heat transfer tubes of the steam generator.   
     
     
         8 . The steam generator according to  claim 7 , wherein the partition plates are provided at a plurality of positions. 
     
     
         9 . The steam generator according to  claim 7 , wherein the partition plates are provided so as to overlap each other. 
     
     
         10 . The steam generator according to  claim 7 , wherein the partition plates are provided with a penetration hole. 
     
     
         11 . The steam generator according to  claim 10 , wherein the penetration hole is formed as an orifice. 
     
     
         12 . The steam generator according to  claim 7 , wherein the support portion is a tube support plate that is supported to the cylinder portion so as to fix the heat transfer tubes. 
     
     
         13 . The steam generator according to  claim 7 , wherein the support portion includes an annular portion that surrounds the U-bent portion at the inside of a tube bundle shroud surrounding an outer peripheral portion of the U-bent portion, a tube bundle shroud inner member that is interposed between the tube bundle shroud and the annular portion at the inside of the tube bundle shroud and supports the annular portion, and a tube bundle shroud outer member that is interposed between the tube bundle shroud and the cylinder portion at the outside of the tube bundle shroud and supports the tube bundle shroud inner member, and the partition plate is supported by the annular portion. 
     
     
         14 . The steam generator according to  claim 7 , wherein the support portion includes a tube bundle shroud outer member that is interposed between the tube bundle shroud and the cylinder portion at the outside of a tube bundle shroud surrounding an outer peripheral portion of the U-bent portion, and an end of the partition plate extending to the tube bundle shroud is supported by the tube bundle shroud outer member. 
     
     
         15 . The steam generator according to  claim 7 , wherein the support portion includes a tube bundle shroud inner member that is provided at the inside of a tube bundle shroud surrounding an outer peripheral portion of the U-bent portion and a tube bundle shroud outer member that is interposed between the tube bundle shroud and the cylinder portion at the outside of the tube bundle shroud and supports the tube bundle shroud inner member, and the partition plate is supported so as to be sandwiched between the plurality of tube bundle Shroud inner members. 
     
     
         16 . The steam generator according to  claim 7 , wherein a bonding mechanism is provided between the support portion and the partition plate or between members of the support portion so as to bond them to each other with a predetermined gap therebetween. 
     
     
         17 . The steam generator according to  claim 7 , Wherein a damping mechanism is provided between the support portion and the partition plate or between members of the support portion so as to connect them to each other and damps a relative movement therebetween while allowing the movement. 
     
     
         18 . A steam generator comprising:
 a U-bent portion in which a plurality of bent portions of a plurality of heat transfer tubes are formed in a U-shape so as to form a semi-spherical shape on the whole and are disposed in the out-of-plane direction perpendicular to a plane including the bent portions;   a tube bundle shroud that surrounds the U-bent portions at the outer peripheral side thereof and   a beam member that is disposed near a top portion of the U-bent portion so as to have a gap with respect to the U-bent portion and has both ends fixed to an inner peripheral surface of the tube bundle shroud so that the beam member extends in the out-of-plane direction along a semi-spherical surface of the U-bent portion.   
     
     
         19 . The steam generator according to  claim 18 , further comprising:
 a movement regulation portion that regulates a relative movement of the U-bent portion with respect to the beam member in the out-of-plane direction.   
     
     
         20 . The steam generator according to  claim 19 , wherein
 the movement regulation portion includes
 a plurality of vibration preventing members that are disposed between the adjacent heat transfer tubes in the out-of-plane direction so as to connect the adjacent heat transfer tubes to each other and has an end protruding from the semi-spherical surface, 
 a bridge that connects ends of the plurality of vibration preventing member to each other in the extension direction of the bent portion, and 
 a regulation member that is provided in the beam member and sandwiches the bridge with a predetermined gap therebetween in the out-of-plane direction. 
   
     
     
         21 . The steam generator according to  claim 18 , further comprising:
 a cylinder portion that is provided at the outer peripheral side of the tube bundle shroud and accommodates the tube bundle shroud and the plurality of heat transfer tubes; and   an outer tube support member that is disposed throughout an inner peripheral surface of the cylinder portion and an outer peripheral surface of the tube bundle shroud and supports the tube bundle shroud.   
     
     
         22 . The steam generator according to  claim 18 , wherein a plurality of the beam members are provided with a gap therebetween in the extension direction of the bent portion. 
     
     
         23 . The steam generator according to  claim 18 , wherein each beam member is obtained by connecting a plurality of divided beams in the out-of-plane direction. 
     
     
         24 . The steam generator according to  claim 18 , wherein the beam member forms a truss structure.