JPS59100895A - Nozzle - 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] [Field of Application of the Invention] The present invention relates to a nozzle suitable for injecting cold water into high-temperature water, and particularly to a nozzle suitable for injecting cold water into a nuclear reactor pressure vessel. Regarding.

[Prior art]

A large number of nozzles are attached to the reactor pressure vessel for purposes such as circulating coolant. Generally, the inside of the reactor pressure vessel is in a high temperature state, and the high temperature reactor water (280 tll)
In some cases, it is necessary to inject cold water (minimum 10C) into the reactor. Therefore, the nozzle body is subjected to severe thermal stress (due to the high-temperature reactor water and the injected cold water). A long sleeve is attached to the nozzle that leads cold water into the pressure vessel to protect the nozzle body from severe thermal stress. Figures 1 to 3 show how to protect the nozzle body from thermal stress. Let me explain.

FIG. 1 is a sectional view showing the entire nuclear reactor pressure vessel.

In FIG. 1, a reactor pressure vessel IO is provided with a large number of nozzles 12 for connecting various pipes. As shown in FIG. 2, this nozzle 12 has a thermal sleeve 16 inserted into a nozzle body 14. This thermal sleeve 16 prevents the cold water shown by the arrow 18 from coming into direct contact with the inner surface 20 of the nozzle body 14 that is in contact with high-temperature reactor water, and prevents the generation of thermal stress in the nozzle body 14. Pour the cold water 18 into the tip of the thermal sleeve 16
A sparger (not shown) with a sparger installed at the right end of FIG. 2 is injected into the reactor pressure vessel.

However, in the nozzle 12 using such a plug-in type Mars IJ, when cold water 18 is injected into the reactor pressure vessel 10, the thermal sleeve 16 contracts and the thermal sleeve 16 and the nozzle body 14, a gap is created between the two. Therefore, as shown by arrows 22 and 23, the cold water 18 leaks from between the thermal sleeve 16 and the nozzle body 14, mixes with the high-temperature reactor water in the corner 24 of the nozzle body 14, and Thermal fatigue occurs in the portion 24 due to high cycle thermal fluctuations. Therefore, the attachment of the thermal sleeve 16 to the nozzle body 14 is approximately 0.2 to 0.2 mm.
A method has been considered in which a tightness of about 0.5 m is provided to minimize the gap that occurs when cold water is injected. However, even in this case, it is not possible to prevent the contraction of the one I-ring sleeve when cold water is injected, and leakage of cold water occurs.

Furthermore, the insertion type thermal sleeve 16 is generally made of Inconel or stainless steel, and the nozzle body 14 is made of carbon steel. Therefore, corrosion of the metal on the nozzle body side,
It is conceivable that aging deterioration due to lotion, etc. occurs, and when the thermal sleeve 16 is installed, the gap between the nozzle body 14 and the thermal sleeve 16 gradually increases, leading to increased leakage of cold water. Furthermore, the length of the sleeve, which should have provided a tightening margin, is subject to thermal cycles during reactor operation, and there is a risk that the tightening margin will gradually disappear and the fit will become loose, resulting in so-called sagging. .

FIG. 3 is a sectional view of a nozzle designed to eliminate the above drawbacks. In the nozzle 12 shown in FIG. 3, a thermal sleeve 26 is welded to an end 28 of the nozzle body 14 at a welded portion 3o. This nozzle 12
In this case, the thermal sleeve 26 is attached to the nozzle body 14 without fear of leakage of cold water. However, as shown in FIG. 3, the cold water 18 injected into the reactor pressure vessel 10 from the discharge port 34 of the sparger 32 is bounced back by the reactor groove rostrum 36, causing so-called tin lashback. The splashing water 38 flows in the direction of the nozzle body 14. At this time, the inventors drew in the downward flow 40 in the furnace indicated by the arrow by the splashed water 38, and the corner part 24 of the nozzle body 14 and the inner surface of part B on the right side of the line segment 42
It has been found that high cycle thermal stress can be applied to 0.

Moreover, according to experiments conducted by the inventors, the nozzle 12 using this welding type thermal sleeve 26 is not affected by sedge lashback, for example, in the section A on the left side of the line 42 in FIG. , the annulus section 44 between the nozzle body 14 and the thermal <IJ-p 26
There is no axial flow. Therefore, the cooling water flowing inside the thermal sleeve 26 can
The outer surface of thermal sleeve 26 is cooled, creating a layer of cold water on the outer surface of thermal sleeve 26 . When this cold water layer grows to a certain extent, the f
This causes the inner surface 20 of the nozzle body 14 to undergo rapid temperature fluctuations. In addition, since the thermal sleeve 26 and the nozzle body 14 are connected by welding, the thermal sleeve 26 and the nozzle body 14 are connected by welding.
6 from the nozzle body 14 and inspect the arrangement, a, etc. from the inner surface of the nozzle body 14.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a nozzle that can prevent the generation of thermal stress caused by introducing cold water.

[Summary of the invention]

In the present invention, a thermal sleeve is welded to the nozzle body, and a baffle plate is provided on the thermal sleeve to shield the opening of the nozzle body to prevent splashback of cold water injected from the sparger. The structure is such that thermal stress does not occur in the nozzle.

[Embodiments of the invention]

Preferred embodiments of the nozzle according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are given to the parts corresponding to the parts explained in the prior art, and the explanation thereof will be omitted.

FIG. 4 is a partial sectional view of an embodiment of a nozzle according to the present invention.

In FIG. 4, thermal sleeve 46 is connected to nozzle body 14 via shoulder 28 of nozzle 48. In FIG. That is, after the ring part 50 and the thermal sleeve 46 are welded and connected at the welding part 30, the end part 28 is connected to the welding part 5.
0, it is welded and connected to the nozzle body 14.

Tip of thermal sleeve 46 (right end in Fig. 4)
It is suspected that the diaphragm 9 has a slightly tapered diaphragm 54.
A sparger 56 is tightly fitted into this constriction portion 54.

A baffle plate 58 is attached behind the discharge port 34 of the sparger 56 at an angle θ to the axis 57 of the thermal sleeve 46. This angle θ is determined to be a predetermined angle within the range of 0 to 90 degrees depending on the structure of the reactor pressure vessel 10, the amount of cold water 18 supplied, the downflow 40 in the reactor, etc.
It will be done. Note that the reference numeral 60 shown in FIG. 4 is a reinforcing lip that reinforces the buckle plate 58.

In the nozzle 48 having the above structure, even if the cold water 18 injected into the reactor pressure volume a10 from the discharge port 34 of the sparger 56 collides with the reactor internals 36 and splashes back water 38, the buckle plate 58 can shield the splashed water 38 and prevent the splashed water 38 from reaching the nozzle body 14.

Therefore, the nozzle body 14 is not subjected to high cycle thermal stress. Moreover, the buckle plate 58 and the nozzle body 1
The in-furnace downward flow 40 flows into the annulus portion 44 from between the thermal sleeve 46 and the thermal sleeve 46, thereby preventing the cold water layer from forming on the outer surface of the thermal sleeve 46. Note that generation of thermal stress can also be prevented when a high temperature liquid is injected into a cold liquid.

FIG. 5 shows the effect of providing the buckle plate 58. The temperature fluctuation prevention effect shown on the vertical axis in Figure 5 is based on the assumption that the temperature fluctuation when no buckle plate is provided is 0%.
The state where there is no temperature fluctuation is defined as 100%. As is clear from FIG. 5, the temperature fluctuation prevention effect is maximized when the angle θ of the baffle plate 58 is about 60 degrees. Therefore, it is generally desirable to set the angle θ to 45 degrees to 80 degrees. In this way, in this embodiment, temperature fluctuations caused by cold water leakage from conventional plug-in thermal sleeves can be reduced to 1.
00% can be prevented, and temperature fluctuations associated with splash packs caused by conventional welded thermal sleeves can be reduced by approximately 1.
00% can be prevented and 1% temperature fluctuation due to the influence of heat transfer by cold water on the outer surface of the thermal sleeve - and about 5%
0% can be prevented. However, in the nozzle 48 of this embodiment, the temperature fluctuation is about 1/1 of the temperature fluctuation when using a conventional welded type thermal sleeve.
It can be improved to about 0.

FIG. 6 is a sectional view of another embodiment of the nozzle according to the present invention.

In the practical example shown in FIG. 6, the sparger 56 is welded to the diaphragm 9 54 of the thermal sleeve 46 at a weld 62. A baffle plate 64 is fixed to the circumferential surface of the sparger 56. This baffle plate 64
A reinforcing lip 66 is provided on the ridge surface, and this reinforcing lip 6
6 is fixed to the nozzle body 14 via a bracket 68.

The baffle plate 64 has an umbrella-shaped half-inverted structure as shown in FIGS.
It can be attached to.

〔Effect of the invention〕

As explained above, according to the present invention, by welding the nozzle body and the thermal sleeve and providing a baffle plate to cover the nozzle body opening, it is possible to prevent thermal stress from occurring in the nozzle. I can do it.

[Brief explanation of the drawing]

Figure 8g1 is a sectional view showing the entire reactor pressure vessel, Figure 2 is a sectional view of a nozzle using a plug-in thermal sleeve, and Figure 3 is a sectional view of a nozzle using a conventional welded Sakizuki thermal sleeve. FIG. 4 is a cross-sectional view of an embodiment of the nozzle according to the present invention, FIG. 5 is a diagram showing the relationship between the angle of the buckle plate and the effect of preventing temperature fluctuations, and FIG. 6 is another cross-sectional view of the nozzle according to the present invention. FIG. 7 is a front view of the baffle plate shown in FIG. 6, and FIG. 8 is a side view of the buckle plate shown in FIG. 6. 12.48... Nozzle nope 14... Nozzle body, 1
6゜26.46... Thermal sleeve, 30, 52゜62... Bath contact part, 32.56... Sparger, 58
゜64...Baffle plate. Izumi Figure 1 Figure 2 House 30 [〒 Figure 7 Figure 68

Claims (1)

[Claims] l. A nozzle body provided in a container in which high-temperature fluid circulates, a thermal sleeve attached to the inside of the nozzle body, and a sparger connected to the thermal sleeve for injecting low-temperature fluid into the container. A nozzle, characterized in that the thermal sleeve is connected to the nozzle main body in four connections, and a buckle plate for shielding the nozzle main body opening is removably attached to the thermal sleeve. 2. The nozzle according to claim 1, wherein the baffle plate is connected by bath welding to the sparger which is removably fitted to the thermal sleeve. 3. The nozzle according to item 1 or 2, wherein the buckle plate has an opening angle of 90 degrees to 160 degrees toward the inside of the container.