Water supply tube for steam generator

Abstract

The water supply tube for steam generator includes an insert tube portion inserted in a penetration hole of a shell member and a generator internal tube portion connected to the insert tube portion. The generator internal tube portion includes a tubular passage and an effluence tube allowing effluence of cooling water in the tubular passage to a space in a steam generator. The tubular passage includes a first tilted portion in which a side having a greater distance from the insert tube portion along a flow direction is located vertically higher than a side having a smaller distance from the insert tube portion and a second tilted portion which is located with a greater distance from the insert tube portion than the first tilted portion.

1 . A water supply tube for a steam generator comprising:
 an insert tube portion horizontally extending and configured to be inserted in a penetration hole penetrating a shell member of the steam generator; and   a generator internal tube portion connected to the insert tube portion and arranged inside the steam generator,   wherein the generator internal tube portion includes a tubular passage formed in an axial direction of the generator internal tube portion and an effluence unit allowing effluence of cooling water in the tubular passage from the tubular passage to a space in the steam generator, the tubular passage allowing cooling water supplied from outside the steam generator via the insert tube portion to flow in the tubular passage,   wherein the tubular passage includes a first tilted portion which is tilted so that a side having a greater distance from the insert tube portion along a flow direction of cooling water is located vertically higher than a side having a smaller distance from the insert tube portion and a second tilted portion which is located with a greater distance from the insert tube portion along the flow direction than the first tilted portion and is tilted so that a side having a greater distance from the insert tube portion along the flow direction is located vertically lower than a side having a smaller distance from the insert tube portion, and   wherein, in at least a portion of a section, along the flow direction, of the tubular passage between the first tilted portion and the second tilted portion, a bottom end of a cross section, perpendicular to the flow direction, of the tubular passage is arranged vertically higher than a horizontal plane including a top end of an inner wall surface of the insert tube portion at a connection between the insert tube portion and the generator internal tube portion.   
     
     
         2 . The water supply tube for a steam generator according to  claim 1 , wherein the effluence unit is not included in a section, of the generator internal tube portion, in which the first tilted portion is formed. 
     
     
         3 . The water supply tube for a steam generator according to  claim 1 , wherein the generator internal tube portion includes a ring tube portion extending in a ring shape along an inner circumferential surface of the shell member and a connection tube portion branching off from the ring tube portion to connect the ring tube portion and the insert tube portion,
 wherein the first tilted portion is provided as the tubular passage formed in the connection tube portion, and   wherein the second tilted portion is provided as the tubular passage formed in the ring tube portion, the second tilted portion being formed on each of both ends, in an axial direction, of the ring tube portion with the connection tube portion in between.   
     
     
         4 . The water supply tube for a steam generator according to  claim 3 , wherein a horizontal ring tubular passage which is the tubular passage extending in a horizontal direction is formed in a portion, arranged farther than the second tilted portion from the insert tube portion along the flow direction, of the ring tube portion, and
 wherein a top end of a cross section, perpendicular to the flow direction, of the horizontal ring tubular passage is provided vertically lower than the horizontal plane including the top end of the inner wall surface of the insert tube portion at the connection between the insert tube portion and the generator internal tube portion.   
     
     
         5 . The water supply tube for a steam generator according to  claim 3 , wherein a horizontal ring tubular passage which is the tubular passage extending in a horizontal direction is formed in a portion, arranged farther than the second tilted portion from the insert tube portion along the flow direction, of the ring tube portion, and
 wherein a top end of a cross section, perpendicular to the flow direction, of the horizontal ring tubular passage is arranged vertically lower than a lower limit of a target for controlling a water level of cooling water in the space in the steam generator.