KR20030064634A - Direct vessel injection system for emergency core cooling water using vertical injection pipe, sparger, internal spiral threaded injection pipe, and inclined injection pipe - Google Patents

Abstract

PURPOSE: A direct vessel injection system of an emergency core coolant using inner screw threads of a vertical injection leg, a sparger, and an injection hole and an inclined injection hole is provided to prevent a degradation phenomenon due to impingement, breakup, and bypass by using the gravity in an injection process. CONSTITUTION: A direct vessel injection type a pressurized water reactor, a boiling water reactor, and an advanced reactor(1) of a direct vessel injection method includes a direct vessel injection system of an emergency core coolant in order to permeate the cooling water of a safety injection leg(4) into a center of the reactor by adding a vertical leg(6) to a safety injection leg horizontal to a reactor vessel. The width of the vertical leg is equal to the width of the safety injection leg. A lower end portion of the vertical leg is installed at a position higher than an upper end portion of a cold leg(2).

Description

DIRECT VESSEL INJECTION SYSTEM FOR EMERGENCY CORE COOLING WATER USING VERTICAL INJECTION PIPE, SPARGER, INTERNAL SPIRAL THREADED INJECTION PIPE, AND INCLINED INJECTION PIPE}

The present invention relates to an emergency core coolant reactor direct injection system using a vertical pipe, a sparger, a screw thread inside an injection pipe, an inclined injection pipe, and a safety injection pipe installed at an upper head of the reactor, and more specifically, the safety injection water is a low temperature pipe. In pressurized water boiling boiling water type or new reactors having safety injection method of direct injection vessel, which is injected into the safety injection pipe installed separately from, the vertical pipe is added to the safety injection pipe horizontal to the reactor vessel. An emergency core coolant injection system, in which a sparger is installed or a screw thread inside the injection pipe, allows the coolant injected into the safety injection pipe to penetrate the core vertically in the vertical direction. The emergency core coolant injection system and the safety injection pipe installed have an angle on the reactor vessel wall. And it relates to an emergency core cooling water injection system to be installed is the injected cooling water penetration into the core at a predetermined angle.

Among nuclear reactors that produce energy using nuclear nucleus as fuel, in particular, the use of hard water as a coolant, which is a heat energy carrier medium generated by nuclear reaction of nuclear fuel, and the pressure inside the reactor is constant so that the coolant does not boil in the reactor vessel. Reactors that are kept larger than their size are called Pressurized Water Reactors (PWRs), and reactors where the coolant boils in a reactor vessel to produce steam directly are called Boiling Water Reactors (BWRs).

When designing such a pressurized light reactor or a boiling light reactor, a virtual accident that is difficult to occur in practice is considered. For these virtual accidents, the boundary of the reactor coolant system is damaged and the coolant flows out of the system. It is called a loss accident.

If a coolant loss occurs in the reactor, the temperature on the surface of the fuel rods will rise rapidly. Therefore, in the event of a coolant loss accident that causes the fuel rod surface temperature to rise rapidly, the reactor can be engineered with the safety of emergency core coolant from outside to high pressure into the reactor vessel. ESF) is installed, commonly referred to as Emergency Core Cooling System (ECCS).

Emergency cooling water injection into the reactor core from the safety injection system of the reactor includes cold leg injection (CLI) and direct vessel injection (DVI). In the related art, a safety injection line has been used in which a safety injection nozzle is connected to each low temperature pipe to inject safety injection water through the low temperature pipe. The existing low temperature pipe injection method consists of two safety injection lines (train) and places high pressure safety injection pump and low pressure safety injection pump on each safety injection line so that the low temperature pipe is broken and one of the safety injection lines It is designed to inject emergency core coolant into each cold tube even when not in operation. However, according to the results of the Probabilistic Safety Assessment (PSA) for nuclear power plants, the design of the safety injection system as a mechanical four-safe injection line can significantly improve the safety of the power plant compared to the two-safe injection line. Turned out to be.

However, if the safety injection system is designed as a four-safe injection line and the low-temperature pipe injection method is used, sufficient flow rate for core cooling is required when the emergency power system can only use the 1-safe injection line due to the loss of large coolant that breaks the low temperature pipe. The high pressure safety injection pump and the low pressure safety injection pump each need four. On the other hand, in this case, if the reactor vessel direct injection method is used, the system can be configured with a pump having a capacity smaller than the conventional safety injection capacity at the time of cold tube breakage. In addition, as in the conventional emergency core cooling system, when the safety injection nozzle is connected to the low temperature pipe, the safety injection water to be introduced into the reactor core side through the safety injection nozzle does not reach the core when the low temperature pipe breakage accident occurs. Problems arise. That is, since the safety injection water flowing through the safety injection nozzle is mixed with the coolant flowing back to the low temperature pipe due to the pressure difference, the safety injection water does not reach the core because the safety injection water flows out through the break portion of the low temperature pipe.

In recent years, such a problem has been considered, and as shown in FIG. 3, the safety injection pipe is directly connected to the reactor vessel and the emergency core cooling water is directly introduced into the reactor vessel, so that even if the low temperature tube is broken, the low temperature of the safety injection water is broken. It has been proposed to allow the safety injection to cool down the core so that it does not flow out of the system through the pipe and thus reaches the core side. In this way, the safety injection pipe is directly connected to the reactor vessel so that the emergency core cooling water is directly injected into the reactor vessel is called a reactor vessel direct injection method.

In the current trend of technological development, the US advanced reactor, System 80 + ^™ , is designing an emergency core cooling system by direct injection of 4-safety injection reactor vessels. The Advanced Power Water Reactor Utility Requirements Document (ALWR URD) of the Electric Power Research Institute (EPRI) has also introduced the safety injection of the emergency core cooling system into the reactor vessel from the conventional low-temperature tube injection method. It is recommended to design by injecting directly into the precipitation part. In this trend, the reactor reactor direct injection method was adopted as the emergency core cooling water injection method in Korea's new water reactor APR1400 design.

However, even in such a reactor vessel direct injection method, there is a possibility that the safety injection water flows out. That is, when the safety injection pipe is installed above the low temperature pipe, when the low temperature pipe that is the coolant inlet pipe is broken, the safety injection water injected through the safety injection pipe moves along the inner wall of the reactor vessel and flows back to the broken low temperature pipe. In addition, there is a possibility that a significant amount of spillage through the low temperature pipe. However, when the safety injection pipe is installed under the low temperature pipe, the safety injection water at low temperature flows rapidly into the reactor vessel at high temperature and high pressure through the safety injection pipe, and thus pressurized thermal shock (PTS) is generated. Not only does the integrity of the container 1 occur, but the amount of coolant flowing out through the safety injection pipe, in particular when the safety injection pipe is broken, causes the direct container injection nozzle 6 to attach to the reactor cold tube nozzle 2. There are many more problems than that.

In order to solve this problem, US Patent Publication No. 5135708, Method of injection to or near core inlet, aims to maximize the effect of safety injection, from the safety injection tube at the top of the cold tube inside the reactor vessel to the bottom of the core support. A method of installing a cylindrical or tubular safety injection passage is disclosed.

However, this method can supply the safety injection water directly to the bottom of the core in the event of cold tube breakage, but if the safety injection pipe breaks out of the reactor vessel, the siphon effect will result in the siphon effect. Since the coolant is continuously drawn out of the coolant level in the reactor vessel until the core is fully exposed, there is a serious consequence of a significant shortage of coolant to prevent the core from melting in the reactor vessel.

In addition, Korean Patent Publication No. 10-0319068, 'Safe injection line in the reactor to block the siphon effect and the contact with the steam flow rate,' shows the amount of safety injection water flowing into the cold tube when the cold tube breakage, which is the coolant inlet pipe, occurs. It is a direct injection nozzle that is installed at a position higher than the low temperature pipe of the reactor and is connected with a gap to minimize the siphon effect that minimizes the coolant flow through the safety injection pipe and blocks the contact with the steam flow. Disclosed is a direct injection nozzle having a safety injection pipe for bypassing and inducing the safety injection water injected from the reactor inlet nozzle and injecting it into the lower space of the reactor vessel.

However, such a nozzle is said to prevent the siphon effect through the gap, but it is difficult to prevent the siphon effect due to the safety injection pipe which injects the emergency core coolant at a lower position than the low temperature pipe in the reactor vessel. Pressurized heat shock is expected as the coolant is sprayed in too close a position.

Accordingly, an object of the present invention is to effectively prevent the pressurized heat shock and siphon effect by using a direct injection system of an emergency core coolant reactor vessel using a vertical pipe, a sparger, and an inclined injection pipe. In addition, the present invention is to increase the momentum in the downward direction through the vertical direct injection to compensate for the disadvantage that the large amount of coolant bypasses the break during the injection of emergency core coolant to increase the downward momentum through the vertical direct injection to the bottom without being bypassed by steam in the reactor precipitation section The purpose is to increase the amount of infiltrating safety injection water.

More specifically, the reactor direct injection method of the present invention is to maintain the temperature of the fuel rod temperature below an appropriate level in the reactor using the emergency core coolant direct injection method during the loss of coolant of the Nuclear Steam Supply System (NSSS). The objective is to infiltrate the safety injection water into the lower plenum through the downcomer more efficiently and stably than the conventional horizontal injection method. In the commonly used reactor vessel direct injection method, since the coolant injected into the reactor vessel horizontally flows in the circumferential direction, the amount of diverting to the breakage portion is not large due to the vertically rising steam from the lower portion of the precipitation portion. . However, the vertical direct injection method of the reactor vessel greatly increases the vertical momentum of the safety injection water and the safety injection water injected in the horizontal direction does not occur in the circumferential direction due to the impingement phenomenon that the circumferential direction does not occur. It aims to significantly reduce the likelihood of nuclear fuel rod exposure by bypass.

In addition, the present invention is intended to play a major role in securing reactor safety when applied to the reactor vessel direct injection system applied to the new water reactor APR1400.

Other objects and applications of the present invention will become apparent to those skilled in the art from the following detailed description.

1 is a schematic representation of one embodiment of a reactor vessel vertical direct injection.

2 is an expected cross-sectional view of a reactor vessel vertical direct injection of APR1400.

Figure 3 is a cross-sectional view of one embodiment of the cold tube injection method and the reactor vessel direct injection method.

Figure 4 is a cross-sectional view of an embodiment of the DVI vertical injection method using a protective plate (a) is a perspective view of the protective plate is installed in the reactor, (b) is a partial enlarged view showing a state that the original plate is attached to the protective plate.

5 is a view showing a DVI vertical injection method using a sparger according to an embodiment of the present invention, (a) is a bottom view of the reactor in which the sparger is installed, and (b) is a sparger (C) is a cross-sectional view schematically showing the cross section of the sparger from the top of the reactor where the reactor is installed.

Figure 6 (a) is a cross-sectional view of one embodiment of the method of inclining the DVI, (b) is a cross-sectional view of one embodiment of the DVI horizontal injection for comparison with the inclined injection of (a).

Figure 7 is a perspective view showing the processing of the screw thread inlet portion of the safety injection water injection pipe.

8 is a top view of the emergency cooling water inlet pipe (DVI tube) installed in the reactor upper head according to an embodiment of the present invention.

Figure 9 is a perspective view of the precipitation portion using the CFX code for the multi-dimensional flow experiment for the (a) horizontal injection method and (b) the vertical injection method of the direct injection method according to an embodiment of the present invention.

FIG. 10 is a comparison diagram illustrating a downward velocity distribution of (a) horizontal injection and (b) vertical injection by performing a multidimensional flow experiment according to the precipitation part model according to FIG. 9. FIG.

11 is a constant velocity profile of horizontal and vertical injection through multi-dimensional flow experiments.

12 is a schematic diagram of the arrangement of precipitation nozzles used in multidimensional flow analysis.

FIG. 13 is a graph comparing speed distribution according to height from a safety injection pipe of a DVI and a DVVI method when injecting emergency core coolant through each nozzle of FIG. 12; FIG.

FIG. 14 is a graph comparing the velocity distribution of (a) horizontal injection and (b) vertical injection in which the graph of FIG. 13 is combined. FIG.

* Description of the symbols for the main parts of the drawings *

1: Reactor 2: Low temperature tube

3: low temperature pipe injection line 4: container direct injection pipe

5: Reactor top head 6: Vertical injection pipe

7: Protection board 8: Precipitation

9: high-temperature tube 10: sparger

Hereinafter, a direct injection system of an emergency core coolant reactor vessel using a vertical pipe, a sparger, a screw thread inside an inlet and an inclined injection tube, and a reactor vessel direct injection system in which the emergency core coolant injection tube is installed on the upper head of the reactor vessel. It will be described in detail with reference to the accompanying drawings with respect to.

Emergency core coolant reactor direct injection system using vertical pipe, sparger, threaded thread and inclined injection pipe according to the present invention, and safety injection water having such emergency core coolant injection pipe installed at the upper head of the reactor vessel are separate from the low temperature pipe. In pressurized water type, boiling water type or new type reactors with safety injection method of direct injection of reactor vessels installed in the safety injection pipe installed in the reactor, a vertical pipe is added to the safety injection pipe horizontally in the reactor vessel. The emergency core coolant injection system and safety injection pipe, which allow the coolant injected into the safety injection pipe to penetrate the core in the vertical direction or form a screw thread in the injection pipe, make the injection water less resistant to steam and penetrate the core. Coolant injected and installed at a certain angle on the core It is composed of an emergency core coolant injection system that effectively injects the safety injection water by maximizing the vertical momentum of the injection water by discharging or installing the safety injection pipe in the upper head of the reactor.

The above system will be described in more detail below.

1 is a pressurized hard water type, boiling hard water type, or new reactor (1) having a safety injection method of the reactor vessel direct injection method in which safety injection water is injected into the safety injection pipe (4) installed separately from the low temperature pipe (2). In this case, a vertical core 6 is attached to a safety injection tube 4 horizontally in a reactor vessel, so that the emergency core coolant injection system allows the coolant injected into the safety injection tube to penetrate the core in the vertical direction.

Safety injection pipe (4) is located in the upper portion of the low temperature pipe (2), which, as described in the prior art, when the safety injection pipe is installed below the low temperature pipe, if the safety injection pipe breaks accident occurs rather than the safety injection pipe This is to prevent the coolant because of the risk of leakage. The reactor vessel of this system uses the same system as the normal horizontal direct injection and the outside of the reactor, and has the structure of the vertical injection type differently from the horizontal inside the reactor, and the vertical pipe 6 has a width of the safety injection pipe. It is almost equal to the width of, and the position of the bottom of the vertical tube is above the top of the cold tube. Since the width of the vertical pipe 6 is about the same as the width of the safety injection pipe 4, the inflow pressure of the safety injection water is not increased further by the vertical pipe, so that the safety injection water is easily introduced. If the width of the vertical pipe is smaller than the width of the safety injection pipe or the width of the precipitation section, there may be leakage of coolant due to the siphon effect through the vertical pipe so that the width of the vertical pipe is approximately equal to the width of the safety injection pipe. It is. The length of the vertical tube may vary in a range where the position of the bottom of the vertical tube does not reach the top of the cold tube. If the bottom of the vertical pipe is lower than the top of the low temperature pipe, the coolant may flow from too close to the core and pressurized heat shock may occur. Also, in the event of a breakdown of the safety injection pipe, the safety injection pipe must be supplied. The coolant in the reactor vessel is discharged until the water level is lower than the lower part of the vertical injection pipe, and the coolant flowing through the low temperature pipe can flow into the safety injection pipe, so that more leakage occurs, so the water level in the core is lowered. The core is not cooled properly and is dangerous.

FIG. 2 is an example of the reactor vessel vertical direct injection of the APR1400, which is an example of the reactor according to the present invention showing the shape and dimensions of the entire reactor so that the height of the safety injection pipe with a vertical pipe installed thereon can be viewed.

3 is a cross-sectional view of an embodiment of a cold tube injection method and a reactor vessel direct injection method, showing a safety injection pipe 4 of a direct injection method and a safety injection line 3 connected to a low temperature pipe according to the prior art. As can be seen from Figure 3, when the safety injection line is connected to the low temperature pipe, it can be seen that the safety injection water flows out of the break site without entering the reactor vessel during the cold tube breakage accident. In comparison, the direct injection method does not have such a risk.

Figure 4 is a cross-sectional view of an embodiment of the vertical injection of the reactor vessel direct injection using a protection disk (a) is a perspective view of a reactor with a protective plate, (b) is a view attached to the original plate of an embodiment of the protective plate Is a partial enlarged view. Referring to Figure 4 (a) is to attach the protective plate 7 to the inlet of the vertical pipe (6) to minimize the resistance of the steam and to maximize the core penetration of the safety injection water. This plate (7) resists the inflow of emergency core coolant due to the heat of the uncooled core in the event of loss of coolant, which can be used to minimize the resistance of the steam and maximize the core penetration of the safety injection. Install at the entrance of straight pipe. (b) shows a shape in which the conical plate is installed at the inlet of the vertical pipe through three connecting lines as an example of such a protective plate. By using such a conical plate, it is possible to minimize the disturbance of the downfall of the injection water due to the resistance of the steam.

5 is a view illustrating a vertical injection method using a sparger according to an embodiment of the present invention, (a) is a bottom view of the reactor in which the sparger is installed, and (b) is a sparger Top view from above of the installed reactor, (c) is a cross-sectional view schematically showing the cross section of the sparger.

5 (a) and 5 (b) illustrate an embodiment in which a method of directly injecting the upper head of a reactor and a method of injecting using a sparger are combined according to an embodiment of the present invention. It is to install the annular tube in the position where the emergency cooling water is injected so that it can be evenly sprayed in the precipitation part.

5 (c) is a pressurized hard water type, boiling hard water type, or a new reactor having a safety injection method of a reactor container direct injection method in which safety injection water is injected into a safety injection pipe installed separately from a low temperature pipe, The sparger 10 is installed in a horizontal safety injection pipe to disclose an emergency core coolant injection system for allowing the coolant injected into the safety injection pipe to penetrate the core in the vertical direction.

6 is a cross-sectional view of an embodiment of a method of inclined injection of cooling water. According to the present invention, in the pressurized hard water type, boiling hard water type or new type reactor having the reactor vessel direct injection method in which the emergency core cooling water is injected into the safety injection pipe installed separately from the low temperature pipe, as shown in FIG. An emergency core coolant injection system is disclosed in which a tube is installed at a constant angle on the reactor vessel wall to allow injected coolant to penetrate into the core at a constant angle. The angle θ may vary in a range of more than 0 ° and less than 90 °, and the larger the angle θ, the more effective the penetration of the safety injection into the core. However, the structure of the reactor may be very complicated and it may be difficult to add such a structure at an inclined angle. In this case, a structure in which the safety injection pipe passes horizontally or vertically is installed and the safety injection pipe therein, that is, the substantially safety injection water is installed. The present invention can be practiced by tilting only the flowing piping.

Figure 6 (b) shows a cross-sectional view of one embodiment of a conventional cooling water horizontal injection method in order to compare with (a). As can be seen from the flow of the safety injection water shown in the drawing, the safety injection water spreads before reaching the core bottom of the reactor in the case of horizontal injection, and its temperature rises to play a role of the safety injection water cooling the core. In the inclined injection method according to the present invention can be seen that the horizontal injection method is superior.

7 is a three-dimensional view showing that a screw thread is processed in the inlet portion of the safety injection water injection pipe. As shown in FIG. 7, when the thread is machined in the inlet portion of the safety injection water, the injected water rotates, and when the bullet is fired while the bullet is fired from the firearm, the air is subjected to less resistance of steam, such as less air resistance. Can effectively penetrate the.

8 is a top view showing a state in which the emergency coolant direct injection pipe is installed in the upper head of the reactor according to an embodiment of the present invention.

Rather than installing the emergency coolant inlet tube on the side of the container as in the prior art, it is possible to maximize the vertical momentum of the injected coolant by installing the upper head of the reactor vessel. As can be seen in Figure 8 the injection tube installed in the upper head according to an embodiment of the present invention is a shape of a vertical tube to the horizontal direct injection tube. The installation of the direct injection pipe in the upper head of the reactor can be applied in combination with other structures of the present invention, that is, vertical pipe, sparger, inclined injection pipe, internal thread, and its utility is high.

The above detailed description of the invention is only for exemplifying the present invention, but it is obvious to those skilled in the art that the scope of the present invention is not limited. Therefore, simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

(Example)

Direct Vessel Vertical Injection (DVVI) that directly injects the vertical pipe among the existing horizontal injection and safety injection pipe injection in the direct vessel injection (DVI) method. An experiment comparing the was performed. Experimental results are shown through qualitative multidimensional flow analysis of horizontal and vertical injection for the injection methodology by DVI. These results are simple multi-dimensional flows, although they depend on simple models and are not supported by experimental studies. Provide enough information to consider how the shape appears in the precipitation section. The CFX code used for the multi-dimensional flow analysis is a well-known multi-dimensional thermofluid analysis tool, and the analysis was performed by simply simulating the precipitation part as shown in FIG. 9. The conditions of this analysis are three-dimensional flow, turbulent flow conditions in the Cartesian coordinate system, incompressible fluid is applied, the gravitational effect is considered, and only liquid phase flow is considered. The system pressure was atmospheric pressure, the system temperature was set at 350K, the safety injection water temperature was set at 288K, and the individual injection speed was set at 12m / s.

The vector distribution of the safety injection water for the two shapes of (a) the horizontal injection method and (b) the vertical injection method of FIG. 9 is the same as that of FIG. 10, and the downward velocity distribution of the vertical injection method is clearer and wider. have.

Fig. 11 shows a surface where the same velocity range (2.5 m / s, 5 m / s) appears in the flow field when the initial injection speed of the safety injection water is 12 m / s. / s is the area where (b) shows the same speed 2.5m / s during vertical injection, (c) is the area that shows the same speed 5m / s during horizontal injection, and (d) is the same when vertical injection It is an area | region which shows the speed 5m / s, (e) is an area | region which shows the same speed 10m / s at the time of horizontal injection, and (f) is an area | region which shows the same speed 10m / s at the time of vertical injection. The difference between vertical injection and horizontal injection is more apparent when comparing the constant velocity planes of (a), (c), (e) and (b), (d), and (f). That is, in the case of vertical injection, the high velocity downward velocity distribution is widely located. In particular, as shown in (c) and (d), the area of the safety injection number in the flow field with 5 m / s appears to be larger during vertical injection, which is a way to maximize the core penetration effect of the safety injection water. .

The analysis of the horizontal and vertical injections of the safety injection water ultimately can only be assessed for its performance by identifying and comparing the bypass of individual injection pipes.

FIG. 12 shows the arrangement of the precipitation nozzles used in the analysis and a schematic of the breakage of the cold tube and FIG. 13 shows the velocity distribution along the height from each individual DVI tube (DVI 1,2,3,4). . Figure 13 (a) shows the velocity distribution according to the height at the time of horizontal injection (DVI 1) and vertical injection (DVVI 1) in DVI 1, (b) is the horizontal injection (DVI 2) and vertical injection (DVVI) in DVI 2 2) shows the velocity distribution according to the height at time, (c) shows the velocity distribution according to the height at horizontal injection (DVI 3) and vertical injection (DVI VI) in DVI 3, and (d) indicates the horizontal distribution (in DVI 4). It shows the velocity distribution according to the height of DVI 4) and vertical injection (DVVI 4). The point where speed is the highest is the injection point of safety injection by DVI, and there is a cold tube break point at about 5.5m in height. 14 is a velocity distribution in each tube in which the injection method is different from horizontal injection and vertical injection. (A) is a velocity distribution in each tube at the time of horizontal injection, (b) is a velocity distribution in each pipe at the time of vertical injection. 14 (a) the horizontal injection shows a large difference in speed at the break according to the position of the injection tube, and (b) the vertical injection infiltrates into the core without a large difference in speed at the fracture. Shows.

As such, the results of the comparison between the horizontal injection and the vertical injection show that the vertical injection is superior in performance and safety by improving the core penetration of the safety injection compared to the horizontal injection.

As described above, the direct injection system of the emergency core coolant reactor vessel using the vertical pipe, the sparger, the thread of the injection pipe and the inclined injection pipe of the present invention, and the direct injection system having such an injection pipe installed on the upper head of the reactor vessel. According to the present invention, since a driven injection type using gravity is used to inject emergency core coolant into the reactor core, impingement, breakup, and bypass generated in the reactor vessel precipitation part after the emergency core coolant is injected. It is possible to prevent the performance of the reactor vessel direct injection system due to the thermal hydraulic phenomenon such as), and to penetrate the emergency core cooling water into the lower cavity more efficiently and stably than the conventional horizontal injection method.

The invention also plays an important role in economics as well as increasing the safety of the nuclear power plant system. Large design of engineered safety features (ESFs), which are often not used at the end of a plant's life, is economically disadvantageous. According to the present invention, a relatively small amount of emergency core coolant injection It is possible to secure the stability of the road can reduce the size of the device occupying a larger capacity than necessary in the design can bring the initial construction cost reduction effect.

In addition, the present invention can be used in the Generation IV nuclear power system currently under development internationally.

Claims (8)

In pressurized water type, boiling water type, or new reactor having safety injection method of direct vessel injection method, in which safety injection water is injected into safety injection pipe installed separately from low temperature pipe, Emergency core coolant injection system that allows the coolant injected through the safety injection pipe to penetrate the core in the vertical direction by adding a vertical pipe to the safety injection pipe that is horizontal to the reactor vessel. The emergency core cooling water injection system according to claim 1, wherein the vertical pipe has a width approximately equal to the width of the safety injection pipe, and the position of the bottom of the vertical pipe is above the top of the cold pipe. The emergency core cooling water injection system according to claim 1, wherein a protection plate is attached to the inlet of the vertical pipe to minimize the resistance of the steam and maximize the core penetration of the safety injection water. The emergency core cooling water injection system according to claim 3, wherein the protection plate is a convex conical plate which is connected to the inlet of the vertical pipe at regular intervals. According to claim 1, Emergency core cooling water injection system for rotating the safety injection water injected by processing the thread on the inner surface of the inlet of the vertical pipe. In a pressurized water, boiling water, or new reactor having a safety injection method of direct injection of the reactor vessel into which safety injection water is injected into a safety injection pipe installed separately from a low temperature pipe, The safety injection water injected through the safety injection pipe is an emergency core coolant injection system to penetrate the core in the vertical direction through a sparger (sparger) of the annular tube form having a plurality of holes in the lower circumferential surface. In a pressurized water, boiling water, or new reactor having a safety injection method of direct injection of the reactor vessel into which safety injection water is injected into a safety injection pipe installed separately from a low temperature pipe, An emergency core coolant injection system in which a safety injection pipe is installed at a constant angle on the reactor vessel wall to allow injected coolant to penetrate into the core at a constant angle. The emergency core cooling water injection system according to any one of claims 1 to 7, wherein the safety injection pipe is installed at an upper head of the reactor vessel.