JPS58218687A - Main steam pipe facility of reactor pressure vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention In particular, it is possible to effectively utilize the piping equipment space in the reactor containment vessel, and to quickly condense the steam flowing in the through pipe basin. The present invention relates to main steam pipe equipment that can reduce blowdown thrust for discharging into a subreduction chamber.

Generally, in nuclear power generation equipment, as shown in the first part [9], the main steam pipe 3 taken out from the upper side surface 2 of the reactor pressure vessel 1 is bent downward after passing above the biological shielding wall 4. It hangs down.

While the main steam pipe 3 is hanging down, it is bent again almost horizontally at a position approximately halfway up the height of the biological shielding wall 4, and is connected to the main steam header 6 supported on the fixed side of the pipe whip structure 5 or the like. , and then further taken out from the rudder 6 into this main steam and hung down again to a predetermined height position,
It was arranged to be guided out of the reactor containment vessel 8 substantially horizontally along the diaphragm floor T.

Further, several spray pipes 9 are taken out from the main steam header 6, which are pressure relief pipes for measuring the pressure reduction in the reactor pressure vessel 1 in case of an emergency such as an accident.

These spray pipes 9 extend directly below the main steam header 6, penetrate the diaphragm floor 1, and are disposed below the water surface 11 in a suppression chamber 10 provided below.

By the way, in the reactor containment vessel 8, the upper area outside the biological shielding wall 4 and separated by the diaphragm floor 7GC is called a dry well 12. Inside this dry well 12, piping for various systems are arranged vertically and horizontally. The arrangement of the through pipes 9 as described above poses a problem in that the space within the dry well 12 cannot be used effectively due to the layout with other piping equipment.

1. In order to prevent the steam pressure inside the main steam pipe 3 from exceeding a certain level, excess pressure steam is always released to the spray pipe 9. The steam discharged into the through pipe 9 is
Since the open end 13 of the tube 9 is submerged below the water surface 11, the pressure inside this tube 9 (hereinafter referred to as blowdown thrust) is completely increased. When this blowdown thrust increases above the water pressure at the open end 13, air bubbles are blown down into the water in the suppression chamber 10. At this time, through pipe 9
Vibration is caused in this through tube 9 due to sudden pressure fluctuations within the tube, and if this vibration occurs repeatedly, there is a risk of damaging the through tube 9. To prevent this, the support had to be completely strengthened. .

The present invention has been devised in view of the above-mentioned problems with VC in order to effectively solve them.

The purpose of the present invention is to make it possible to effectively utilize all the piping equipment space in the reactor containment vessel, to quickly condense the steam flowing in the spray pipe, and to discharge the steam from the spray pipe into the suppression chamber. An object of the present invention is to provide main steam pipe equipment for a nuclear reactor containment vessel that can reduce blowdown thrust.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

As shown in FIG. 2, the reactor pressure vessel 1 is supported with its legs 14 placed on a pedestal 15. As shown in FIG. On this pedestal 15, the reactor pressure vessel 1
A biological shielding wall 4 is provided vertically upward from the outside of the leg 14 to surround the outer periphery of the leg 14 . These reactor pressure vessel 1, pedestal 15, and biological shielding wall 4
The outside of these facilities is covered with metal by a reactor containment vessel 8vc to separate the surrounding area from the outside world. A diaphragm 70a1 is provided between the reactor containment vessel 8 and the destination 15, and the area outside the biological shielding wall 4 and inside the reactor containment vessel 8 is from this diaphragm floor 7VC. It is divided into a dry well 12 in an upper layer and a salt chamber chamber 10 in a lower layer.

On the other hand, the main steam pipe 3 is taken out approximately horizontally from above the side of the reactor pressure vessel 1 that protrudes upward from the upper end surface 16 of the biological shielding wall 4, and passes above the biological shielding wall 4 to the dry well. 12 and extends upward inward. Thereafter, the main steam pipe 3 is bent downward and suspended along the biological shielding wall 4 to a predetermined height close to above the diaphragm floor 14-. Furthermore, this main steam pipe 3 is bent and extended approximately horizontally along the diaphragm floor 7 to maintain the above-mentioned predetermined height, and is taken out of the reactor containment vessel 8. A main steam header 6 is provided in the middle of the pipe in a portion bent at the height and along the diaphragm floor 71C. Several through pipes 9 are branched from the main steam header 6 via safety relief valves and other metals, and then are suspended downward, penetrating the diaphragm floor 1 and flowing below the water surface 11 in the suppression chamber 10 below. The open end 13 is recessed.

Next, the operation of the present invention will be described.

In the piping route of the main steam pipe 3, the outlet branch of the through pipe 9, that is, the installation of the main steam header 6, is located at a height close to the diaphragm floor 1, and is occupied by the installation of the spray pipe 9. The space within the dry well 12 becomes smaller.

Therefore, when arranging piping equipment for other systems, sufficient space will be effectively utilized. Also, the steam discharged from the main steam pipe 3 to the through pipe 9 via the relief safety valve etc. Since the spray pipe 9 is short, it reaches the water surface 11 in the suppression chamber 10 in a short time and is cooled, so that it condenses quickly.

Therefore, the pressure within the spray pipe 9 is quickly reduced, and the blowdown thrust can be reduced. That is, since the steam discharged into the through pipe 9 is immediately condensed, no pressure is accumulated within the pipe 9.

Therefore, the above-described vibration of the spray tube 9 is eliminated from its cause, so there is no possibility of it occurring.

According to the present invention, the following excellent effects are exhibited.

(1) Since the space occupied by the spray pipes is completely reduced, the entire piping equipment space within the reactor containment vessel can be used effectively.

(2) The length of the spray pipe has been shortened, so the steam flowing inside this pipe can be condensed quickly. (3) The blowdown thrust for discharging the steam inside the spray pipe into the subrection channel can be reduced. can do.

(4) By reducing the blowdown thrust, it is possible to completely prevent vibrations occurring in the through pipe.

(5) The structure is simple and can be easily adopted.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional example, and FIG. 2 is a vertical sectional view showing an embodiment according to the present invention. In the figure, 1 is the reactor pressure vessel, 3 is the main steam pipe, 4 is the biological shielding wall, 1 is the diaphragm floor, 8 is the reactor containment vessel,
9 is a spray tube, 10 is a suppression chamber, and 15 is a target to be destroyed. Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Agent: Patent attorney: Nobuo Kinutani Figure 1

Claims (1)

[Claims] A pedestal provided to fully support the reactor pressure vessel, a biological shielding wall provided from the pedestal to surround the outer circumference of the reactor pressure vessel, and a reactor containment vessel provided to cover the reactor containment vessel; a diaphragm floor extending between the reactor containment vessel and the pedestal; A main steam pipe that hangs down and is bent and extended to be taken out of the reactor containment vessel along the diaphragm floor, and a portion of the main steam pipe that is bent along the diaphragm floor. The main steam pipe equipment of the reactor pressure vessel is characterized by a branch formed from this and a sore pipe for releasing pressure to a susolation channel under the diaphragm floor.