JP2002006081A - Coolant draining equipment for reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress corrosion reduction quantity of a liner plate by making early draining surely possible during emergency such as leakage of coolant. SOLUTION: A coolant draining equipment is placed in a coolant path system of a reactor using liquid metal as coolant to drain the coolant through pipes 2, 6 and 8 to drain tanks 9 and 10. In drain pipes 11, 12 and 13, automatic opening valves 14 to 18 to open in emergency are provided. The automatic drain opening valves 14 to 18 are constituted of a plurality of automatic opening and closing valves 14a and 14b to 18a and 18b as one group in parallel and the automatic opening and closing valves 14a and 14b to 18a and 18b are provided in series to the drain pipes 11, 12 and 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drain system for discharging a coolant which is provided, for example, for emergency use in a cooling system or the like of a liquid metal cooled reactor, and more particularly to a primary cooling system, a secondary cooling system and an auxiliary system. The present invention relates to a coolant drain facility of a nuclear reactor applied to a reactor or the like.

[0002]

2. Description of the Related Art In a liquid metal-cooled reactor, for example, a fast reactor, a primary coolant such as liquid sodium passing through a core is exchanged with a secondary coolant such as liquid sodium in an intermediate heat exchanger. The secondary coolant is heat-exchanged with water in an evaporator to generate steam, and the steam drives a turbine or the like. The secondary cooling system or the like is provided with a coolant drain facility for discharging the coolant from the piping in case of emergency such as leakage of the coolant in the system piping.

FIG. 33 shows an example of a conventional coolant drain facility applied to a secondary cooling system of a fast reactor. That is, the secondary system of the illustrated fast reactor is provided with an intermediate heat exchanger 1, and the secondary coolant heat-exchanged with the primary coolant in the intermediate heat exchanger 1 passes through the pipe 2 for feeding. Sent to header 3,
From the header 3, the steam is sent into the steam generator 5 through the distribution pipe 4. In the steam generator 5, steam is generated by heat exchange between the secondary coolant and water. The secondary coolant subjected to heat exchange in the steam generator 5 is sent to a circulation pump 7 through a pipe 6 on the outlet side, and from the circulation pump 7 through a pipe 8 for recirculation, the intermediate heat exchanger. It is to be returned to 1.

Drain tanks 9 and 10 for storing a secondary coolant are provided in the pipes 2, 6 and 8, respectively.
The drain pipes 11, 12 and 13 are connected via drain pipes 11, 12 and 13 branched from the bottoms of the pipes 6 and 8, and automatic opening / closing valves 14 to 18 are provided in the drain pipes 11, 12 and 13, respectively. In an emergency or the like, each of the automatic on-off valves 14 to 1 is used.
8, the secondary coolant in the secondary cooling system is automatically discharged into the drain tanks 9, 10.

The circulating pump 7 has an overflow space 7a for accommodating excess secondary coolant, and the overflow space 7a is provided near the circulating pump 7 for receiving an overflow column for receiving a secondary coolant. 19 is connected through an overflow pipe 20. Thereby, when the liquid level of the secondary coolant in the circulation pump 7 becomes equal to or higher than a predetermined liquid level, the excess secondary coolant is removed from the overflow pipe 20.
Through to the overflow column 19. The overflow column 19 and the steam generator 5 are provided with overflow pipes 21 and 22, respectively.
It is connected to the.

When the liquid level of the secondary coolant in the overflow column 19 or the steam generator 5 becomes equal to or higher than a predetermined liquid level, excess secondary coolant is supplied to the overflow pipe 21,
The secondary coolant is discharged into the drain tank 9 through the pipe 22, and the liquid level of the secondary coolant in the steam generator 5, the overflow column 19, and the circulation pump 7 is maintained at a predetermined liquid level.

Incidentally, in such a secondary cooling system, an air cooler 23 is provided in case a load side such as a turbine trips. This air cooler 23 cools the secondary coolant by heat exchange with air.
It has a heat transfer tube 23a for radiating the secondary coolant. The system of the air cooler 23 will be described. An on-off valve 24 is provided in the pipe 2 on the upstream side of the steam generator 5, and the inflow-side bypass pipe 25
Is branched, and the inflow-side bypass pipe 25 is connected to the air cooler 2.
3 is connected to one end of the heat transfer tube 23a. An on-off valve 26 is also provided on the pipe 6 on the downstream side of the steam generator 5, and an outflow-side bypass pipe 27 is branched from a position on the downstream side of the on-off valve 26 of the pipe 6. The outflow side bypass pipe 27 is connected to the other end of the heat transfer pipe 23 a of the air cooler 23. An on-off valve 28 is provided in the middle of the outflow-side bypass pipe 27.

When a trip occurs on the load side of the turbine or the like, the on-off valve 28 of the outflow side bypass pipe 27
Is opened, the secondary coolant flows to the air cooler 23 through the inflow-side bypass pipe 25 and the outflow-side bypass pipe 27, and the secondary coolant is exchanged with air in the heat transfer pipe 23a of the air cooler 23. As a result, heat generated in the core is finally exhausted.

A cover gas space is also formed in the steam generator 5, the overflow column 19 and the drain tanks 9, 10, and these cover gas spaces are connected to each other by cover gas pipes 29, 30. . The cover gas space of each of these devices can be filled with an inert gas, evacuated, and the like.
A cover having a pressure of ２2 kg / cm ² is sealed, so that the gas pushed out from the drain tank side can be transferred to the secondary cooling system side when the coolant is drained.

Since the above-mentioned secondary cooling system equipment and piping are generally installed in an air atmosphere, if sodium or the like as a secondary cooling material leaks to the outside, the oxygen in the atmosphere is It is possible that a chemical reaction may occur to generate high heat and cause a fire. For this reason, if a leak occurs, the automatic opening / closing valve 14 installed in the drain pipes 11 to 13 is installed in order to prevent the effect of the fire from continuing due to the leakage.
To 18 are opened, and the secondary coolant is urgently sent to the drain tanks 9 and 10.

[0011] A liner (steel receiving pan) is provided on the inner surface of the floor of the building where the equipment and piping are installed so as to store or transfer the leaking sodium.

FIG. 34 illustrates the configuration of a building provided with a liner. As shown in FIG. 34, a sodium pipe 3 connected to a sodium device 31 such as the generator described above.
2 is inserted into a building 33 via a sleeve 34, and a liner 37 is installed via a heat insulating material 36 on a floor 35 facing these pipes 32. The liner 37
Is covered with a lid 38 or the like.

[0013]

If any of the automatic opening / closing valves 14 to 18 cannot be opened due to breakage of the cooling system equipment or piping, the relevant part cannot achieve the function of stopping leakage by drainage. , Leaked coolant is liner 3 for a long time
7, the liner 37 is corroded by the chemical reaction of the steel material of the coolant generated at this time. Therefore, it is necessary to use a thick steel material for the liner 37 in consideration of the corrosion thinning. Was.

Further, depending on the size of the leakage, the ambient temperature may be several hundred degrees centigrade due to the chemical reaction between the coolant and oxygen in the air.
Therefore, a valve driving device (not shown) for driving the automatic on-off valves 14 to 18 has a heat resistant temperature (generally, 1).
00 ° C. to 200 ° C.), whereby the automatic on-off valve 14
It is conceivable that the opening / closing of １８18 may be hindered.

Further, even when the automatic on-off valves 14 to 18 can be opened, the drain speed is limited by the flow resistance of the drain piping and the flow resistance of the cover gas flowing from the drain tank to the cooling system instead of the coolant. Therefore, it is necessary to install a large-diameter drain pipe and a cover gas pipe. Also, since the coolant drains are merged into the drain pipes 11 and 13 and introduced into the drain tank 9, if the coolant drain from one drain pipe ends in advance, the gas flows in from the drain pipe end. However, there is a possibility that the remaining drain flow becomes a two-phase flow and the drain time is extended.

The present invention has been made in view of such circumstances, and an object of the present invention is to surely perform early drainage in the event of an emergency such as leakage of a coolant, thereby preventing liner plate corrosion. It is an object of the present invention to provide a coolant drain facility for a nuclear reactor capable of suppressing a wall thinning amount.

[0017]

SUMMARY OF THE INVENTION According to the present invention, in a cooling system of a nuclear reactor, a plurality of automatic opening / closing valves for drain pipes are installed in order to reliably drain when coolant leaks. In addition to suppressing the flow resistance of the drain pipe and cover gas pipe, effectively suppressing the decrease in the drain flow rate due to gas entrainment, the drain is terminated early, and the valve drive unit is operated in response to the increase in the ambient temperature due to the chemical reaction of the coolant. Proper protection enhances the reliability of the drain function, and quickly and reliably terminates drainage.This significantly reduces corrosion thinning of the liner plate, and improves the reliability and economy of the reactor. The main point is to achieve.

More specifically, the invention of claim 1 is provided in a coolant distribution system of a nuclear reactor using liquid metal as a coolant, and the coolant is discharged from a device or a pipe of the system to a drain tank by a drain pipe. Material drain equipment, wherein the drain pipe is provided with an automatic opening / closing valve which is opened in an emergency, wherein the automatic opening / closing valve is provided by a plurality of parallel ones.
A plurality of automatic on-off valves are provided in the drain pipe and arranged in series.

According to a second aspect of the present invention, a coolant drain is provided in a coolant distribution system of a nuclear reactor using liquid metal as a coolant, and the coolant is discharged from a device or piping of the system to a drain tank through a drain pipe. Equipment, wherein the drain pipe is provided with an automatic on-off valve that is opened in an emergency,
A plurality of the automatic on-off valves are configured as a set of a plurality of automatic on-off valves in series, and a plurality of the automatic on-off valves are arranged in the drain pipe in parallel.

According to a third aspect of the present invention, in the coolant drain system for a nuclear reactor according to the first or second aspect, a drain pipe is integrated at an outlet position of an automatic opening / closing valve arranged near the drain tank to form one drain tank. It is characterized in that each is connected to another drain tank without being connected or integrated.

According to a fourth aspect of the present invention, there is provided a coolant drain system for a nuclear reactor according to the third aspect, wherein the drain pipes are separated from each other without being integrated at an outlet position of an automatic on-off valve arranged near the drain tank. In the tank connected to the tank, the drain pipes that are not integrated are connected to each other by a conduction pipe at a position downstream of the automatic opening / closing valve, and another automatic opening / closing valve is provided in the conduction pipe.

According to a fifth aspect of the present invention, there is provided a coolant drain facility for a nuclear reactor according to any one of the first to fourth aspects,
Two drain pipes hanging from drain nozzles of equipment or pipes having different coolant distribution systems are integrated by a pipe integration part and connected to a drain tank, and one of the two drain pipes, in which the coolant discharge ends first The height difference from the drain nozzle of the drain pipe to the pipe integration part is determined by the pressure loss (water head conversion) when the discharge of the coolant from the drain nozzle of the other drain pipe to the pipe integration part of the other drain pipe ends with a delay. Min.).

According to a sixth aspect of the present invention, there is provided a coolant drain installation for a nuclear reactor according to any one of the first to fourth aspects,
Three or more drain pipes hanging from drain nozzles of equipment or pipes with different coolant distribution systems are integrated by a pipe integration part and connected to a drain tank, and one or more of these drain pipes whose coolant discharge ends first The height difference from the drain nozzle of the drain pipe to the pipe integration part is determined by the pressure loss (water head conversion) when the coolant discharge from the drain nozzle of the other drain pipe to the pipe integration part of the other drain pipe is terminated with a delay. Min.).

According to a seventh aspect of the present invention, there is provided a coolant drain installation for a nuclear reactor according to any one of the first to sixth aspects,
The pipe to which the drain pipe is connected is an overflow pipe for constantly flowing excess coolant in a system through which the coolant flows into the drain tank.

[0025] The invention of claim 8 provides a coolant drain installation for a nuclear reactor according to any one of claims 1 to 7,
The apparatus, piping or drain tank of the coolant distribution system is provided with a pipe and an automatic open / close valve for releasing the cover gas from the apparatus, the pipe or the drain tank together with the emergency discharge of the coolant to the drain tank. And

According to a ninth aspect of the present invention, in a coolant drain facility for a nuclear reactor according to any one of the first to eighth aspects,
The drain tank is provided with a liquid level gauge for measuring the liquid level of the coolant stored in the drain tank. The liquid level gauge is covered with a liquid level gauge sheath, and the drain level is measured through the liquid level gauge sheath. It is inserted and installed in a nozzle portion provided on the upper wall of the tank, and a gap is formed between the liquid level gauge and the liquid level gauge around the liquid level gauge. A seal portion is provided at a position protruding upward from the tank, and the gap has a freezing point before the coolant that enters the gap due to breakage of the liquid level gauge and rises and flows out of the seal portion to the outside. It is characterized in that it is set to have an upwardly protruding length enough to solidify by lowering the temperature.

According to a tenth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to any one of the first to ninth aspects, the drain tank has a temperature for measuring the temperature of the coolant stored therein. The thermometer is covered with a thermometer sheath, inserted through a nozzle portion provided on an upper wall of the drain tank through the thermometer sheath, and the thermometer sheath is provided around the thermometer. A gap is formed between the thermometer and the thermometer and the thermometer sheath have a seal portion at a position protruding upward from the drain tank, and the gap is caused by breakage of the liquid level gauge sheath. It is characterized in that the upwardly protruding length is set such that the coolant that enters the gap and rises is cooled down to the freezing point and solidified before flowing out of the seal portion to the outside.

According to an eleventh aspect of the present invention, in the coolant drain facility for a nuclear reactor according to any one of the first to tenth aspects, the drive unit of the automatic on-off valve installed on each drain pipe is provided by a heat-resistant protective box. It is characterized by being coated.

According to a twelfth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the eleventh aspect, an opening window is provided in the heat-resistant protective box, and a closing lid having heat insulation and elasticity is attached to the opening window. It is characterized by.

According to a thirteenth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the eleventh aspect, an opening window is provided in the heat-resistant protective box, and a heat-insulating closing lid is attached to the opening window. Is characterized in that it is of a normally open type fixed by a fixing jig which closes upon sensing of high heat.

According to a fourteenth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the eleventh aspect, an opening window is provided in the heat-resistant protective box, and a net is installed in the opening window, and the net has heat insulation performance. It is characterized by applying a foaming paint.

According to a fifteenth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the eleventh aspect, the protective box of the automatic on-off valve is covered with a net, and the net is coated with a foaming paint having heat insulating properties. It is characterized by.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a coolant emergency drain equipment system for a nuclear reactor according to the present invention will be described below with reference to FIGS.

First Embodiment (FIG. 1) FIG. 1 is a system diagram showing a secondary cooling system in a drain facility of a fast reactor as a first embodiment of the present invention. Parts that are the same as or correspond to those in the conventional example will be described with the same reference numerals as in FIG. For the building configuration, see FIG.
Since this is the same as that shown in FIG.

In this embodiment, there is provided a heat exchanger 1 for exchanging heat with a primary coolant flowing through a primary cooling system (not shown) of the fast reactor, and the intermediate heat exchanger 1 exchanges heat with the primary coolant. The secondary coolant passed through the feed pipe 2 and the header 3
And from the header 3 through the distribution pipe 4 into the steam generator 5. In the steam generator 5, steam is generated by heat exchange between the secondary coolant and water. The secondary coolant subjected to heat exchange in the steam generator 5 is sent to a circulation pump 7 through a pipe 6 on the outlet side,
And returned to the intermediate heat exchanger 1 through a reflux pipe 8.

The circulating pump 7 has an overflow space 7a for accommodating excess secondary coolant, and the overflow space 7a is provided near the circulating pump 7 for receiving an overflow column for receiving a secondary coolant. 19 is connected through an overflow pipe 20. Thereby, when the liquid level of the secondary coolant in the circulation pump 7 becomes equal to or higher than a predetermined liquid level, the excess secondary coolant is removed from the overflow pipe 20.
Through to the overflow column 19. The overflow column 19 and the steam generator 5 are provided with overflow pipes 21 and 22, respectively, and these overflow pipes 21 and 22 are connected to one drain tank 9.

With this arrangement, when the liquid level of the secondary coolant in the overflow column 19 or the steam generator 5 becomes equal to or higher than a predetermined liquid level, excess secondary coolant is supplied to the overflow pipe 2.
The liquid is discharged into the drain tank 9 via the first and second 22 and the liquid level of the secondary coolant in the steam generator 5, the overflow column 19 and the circulation pump 7 is maintained at a predetermined liquid level.

Incidentally, such a secondary cooling system is provided with an air cooler 23 in case a load side such as a turbine trips. The air cooler 23 cools the secondary coolant by heat exchange with air, and has a heat transfer tube 23a for radiating the secondary coolant. To explain the system of the air cooler 23, an on-off valve 24 is provided in the pipe 2 on the upstream side of the steam generator 5, and an inflow-side bypass pipe 25 is branched from a position on the upstream side of the on-off valve 24 of the pipe 2, The inflow-side bypass pipe 25 is connected to one end of the heat transfer pipe 23 a of the air cooler 23. An on-off valve 26 is also provided on the pipe 6 on the downstream side of the steam generator 5, and an outflow-side bypass pipe 27 is branched from a position on the downstream side of the on-off valve 26 of the pipe 6. The outflow side bypass pipe 27 is connected to the other end of the heat transfer pipe 23 a of the air cooler 23. An on-off valve 28 is provided in the middle of the outflow-side bypass pipe 27.

When a trip occurs on the load side of the turbine or the like, the on-off valve 28 of the outflow side bypass pipe 27
Is opened, the secondary coolant flows to the air cooler 23 through the inflow-side bypass pipe 25 and the outflow-side bypass pipe 27, and the secondary coolant is exchanged with air in the heat transfer pipe 23a of the air cooler 23. As a result, heat generated in the core is finally exhausted.

A cover gas space is also formed in the steam generator 5, the pump overflow column 19, and the drain tanks 9, 10, and these cover gas spaces are
The cover gas pipes 29 and 30 are connected to each other. In addition, the cover gas space of each of these devices can be filled with an inert gas, evacuated, and the like, and a cover with a pressure of 1 to ² kg / cm ² is filled during normal operation, thereby providing a coolant drain. Sometimes, the gas pushed out from the drain tank side can be transferred to the secondary cooling system side.

In such a configuration, drain pipes 11, 12, and 13 are respectively connected to and suspended from the bottoms of the secondary coolant supply pipe 2 and the return pipes 3, 6. Among these drain pipes 11 to 13, drain pipes 11 and 13 connected to the pipe 2 and the pipe 6 are integrated with each other at the lower end side and connected to the first drain tank 9. The connected drain pipe 12 is independently connected to the second drain tank 10. The overflow pipes 21 and 22 respectively led from the overflow column 19 and the steam generator 5 have opening / closing valves, and these overflow pipes 21 and 22 are also integrated with each other and connected to the first drain tank 9. I have.

In this embodiment, the drain pipes 11, 12, and 13 are provided with automatic opening / closing valves 14 to 18 which are opened in an emergency. That is, the drain pipes 11 and 13 which are integrated with each other are provided with automatic open / close valves 14 and 16 respectively at the drooping portions between the pipes 2 and 8 to which they are connected and the integration section (point A), and An automatic opening / closing valve 17 is provided at an intermediate portion from the portion (point A) to the drain tank 9. These automatic on-off valves 1
4, 16 and 17 are two parallel automatic opening / closing valves (valve elements) 1
4a, 14b, 16a, 16b, 17a, and 17b are each configured as one set. This allows
Each of the drain pipes 11 and 13 has two parallel automatic opening / closing valves 14, 16 and 1 in front and behind the integrated portion (point A).
7 are arranged in series two by two.

Also, an upstream piping 6 for returning the secondary coolant is provided.
Is also provided with an automatic open / close valve 15 on the upstream side and an automatic open / close valve 18 on the downstream side in a drooping portion between each pipe 6 to which the drain pipe 12 is connected and the drain tank 10. ing. These automatic opening / closing valves 15 and 18 also have two parallel automatic opening / closing valves (valve elements) 15a, 15b, 18a,
18b, each of which is constituted as one set. Thereby, the drain pipe 12 is also provided with two parallel automatic opening / closing valves 15,18.
Are arranged in series.

As shown in FIG. 33, the liner plate 3 is provided on the inner surface of the floor of the building where the equipment and piping are installed so that the leaking coolant such as sodium can be stored or transferred.
7 are provided.

According to such a configuration, by opening the automatic opening / closing valves 14 to 18 of the drain pipes 11, 12, and 13 in an emergency, the secondary coolant in the secondary cooling system is drained to the respective drain tanks 9, 10. It can be surely discharged into the inside. That is, since the secondary cooling system equipment and piping are generally installed in an air atmosphere, if sodium or the like as a secondary coolant leaks to the outside, chemical reaction with oxygen in the atmosphere will occur. However, if a leak occurs, the automatic on-off valves 14 to 18 installed in the drain pipes 11 to 13 are opened, and the secondary tanks 9 and 10 are opened. Coolant is sent urgently.

In this case, in the present embodiment, drain pipes 11 to 13 are connected to the bottoms of the pipes 2, 6, and 8 of the secondary cooling system. 14a, 14b, 17a, 17b are connected in series, and the drain pipe 13 is connected in parallel with two automatic on-off valves 16a, 16b, 1
7a and 17b are connected in series, and
Since the automatic open / close valves 15a, 15b, 18a, and 18b are installed in series, respectively,
a to 18b can be opened even if any one of the valves in each set does not open.
13 are reliably connected to the drain tanks 9 and 10, and the coolant can be discharged. Further, if the automatic opening / closing valves 14a to 18b in the parallel configuration have the same capacity, even if one of the paired automatic opening / closing valves 14a to 18b cannot be opened, the other is opened for a predetermined time. With this, the coolant can be discharged.

Therefore, according to the present embodiment, when an emergency such as leakage of the coolant occurs, the coolant can be drained reliably and promptly, thereby suppressing the amount of corrosion thinning of the liner plate, or It is possible to prevent the effects of the fire from spreading due to the continued leakage.

In this embodiment, since the coolant supply pipe 2 is longer than the return pipe 8 on the downstream side, the drain pipes 11 and 13 of both pipes 2 and 8 are simultaneously provided. When the coolant is discharged, the drain pipe 13 of the relatively short return pipe 8 is drained early,
Height difference Ho (m) between an integrated portion (point A) of both drain pipes 11 and 13 and a branch point (point B) between pipe 2 and drain pipe 11.
Is the pressure loss that occurs in the drain pipe 11 when it is assumed that the drain pipe 11 alone drains the water.
When the pressure loss (water head equivalent) with respect to the entire length between the point B and the point B is ΔPo (m), the position is such that Ho> ΔPo is satisfied.

In this case, for example, the discharge of the coolant from the pipe 8 through one drain pipe 13 is finished first, and the remaining coolant from the pipe 2 is discharged through the other drain pipe 11. However, there is no possibility that the gas is drawn from one drain pipe 13 and the discharge flow rate of the other drain pipe 11 is reduced. For example, when Ho is only 1/2 of ΔPo, the drain flow rate is reduced to 0.7 times corresponding to 1/2, but this is not the case in the present embodiment.

In the first embodiment described above, a case has been described in which two sets of automatic on-off valves having two parallel units are arranged in series for each drain pipe. Can be two or more arbitrary pluralities. Although not shown, the same applies to the case where three or more drain pipes are integrated, as to how to take the height difference to prevent gas entrainment at the drain pipe integration part (point A).

Second Embodiment (FIG. 2) FIG. 2 is a system diagram showing a second embodiment of the present invention.

As in the first embodiment described above, this embodiment relates to a secondary cooling system in a drain facility of a fast reactor, and has a drain pipe provided with an automatic opening / closing valve which is opened in an emergency. The first embodiment differs from the first embodiment in that a plurality of automatic on-off valves are formed in series as a single set, and a plurality of automatic on-off valves are arranged in a drain pipe in parallel.

That is, as specifically shown in FIG. 2, in the present embodiment, the drain valves 11, 12, and 13 configured in the same manner as in the first embodiment are respectively provided with automatic opening / closing valves 14 to 14 which are opened in an emergency. The drain pipes 11 and 13 that are integrated with each other are provided from the respective pipes 2 and 8 to which they are connected as in the first embodiment.
Automatic opening / closing valves 14, 1
6 is provided, and an automatic opening / closing valve 17 is provided at an intermediate portion from the integrated portion (point A) to the drain tank 9. These automatic on-off valves 14 and 16 are connected in parallel 2
Base automatic on-off valves (valve elements) 14a, 14b, 16a, 1
6b constitutes one set. Thereby, the drain pipes 11 and 13 are arranged in parallel before and after the integrated portion (point A) so that the automatic on-off valves 14 and
Two pairs 16 and 17 are arranged in series.

On the other hand, another drain pipe 12 connected to the pipe 6 on the upstream side for returning the secondary coolant is provided in a hanging part between each pipe 6 to which it is connected and the drain tank 10. Although automatic opening and closing valves 15 and 18 are provided,
The configuration of these automatic on-off valves 15 and 18 is different from that of the first embodiment. In other words, the drain pipe 12 is partially
a, but two branch pipes 12
b, 12c, and one of the branch pipes 12b is provided with two automatic on-off valves (valve elements) 15a, 15b in series.
Are provided in the other branch pipe portion 12c, and automatic on-off valves (valve elements) 18a and 18b of two in-line configuration are also provided. They are arranged in parallel.

The other configuration is the same as that of the first embodiment, and the description is omitted.

According to the second embodiment having such a configuration,
The same operation as in the first embodiment is performed on the drain pipes 11 and 13. The drain pipe 12 is connected in series 2
Since the automatic open / close valves 15a, 15b, 18a and 18b are installed in parallel, even if one of the automatic open / close valves 15 and 18 does not open, the other valve is opened. This allows the coolant to be discharged.

Therefore, according to the present embodiment as well, in the event of an emergency such as leakage of the coolant, the coolant can be drained reliably and early, thereby suppressing the amount of corrosion thinning of the liner plate or leaking. Can prevent the effect of the fire from spreading due to the continuation of the work.

In this embodiment, the case where two sets of automatic open / close valves in parallel or in series are arranged in series or in parallel with each drain pipe has been described. Can be any plural number of two or more.

Third Embodiment (FIG. 3) FIG. 3 is a system diagram showing a third embodiment of the present invention.

This embodiment has the same basic structure as that of the first embodiment, except that the drain pipe 12 is not integrated at the outlet positions of the automatic opening / closing valves 18a and 18b disposed close to the drain tank. The drain pipes 12d and 12e are connected to different drain tanks 10a and 10b, respectively, and the unintegrated drain pipes 12d and 12e are connected to each other by a conduction pipe (tie line) 12f at a position downstream of the automatic on-off valve. The difference is that another automatic opening / closing valve 18c is provided in the conduit 12f. Other configurations are the same as those of the first embodiment, and therefore, the same reference numerals are given to FIG. 3 as in FIG. 1 and the description is omitted.

According to the present embodiment having such a configuration, the automatic on-off valve 18 provided at a portion of the drain pipe 12 near the tank is provided.
Even if any one of the valves a, 18b, and 18c is not opened, the pipe line of the drain pipe 12 is surely connected to the two drain tanks 10a and 10b, and an effect that the drain becomes possible is obtained. Thereby, in addition to the same effects as in the first embodiment, the configuration of the drain tank per unit can be reduced, and the drain pipe 12 from the integration point of the tie line 12f to the drain tanks 10a and 10b can be obtained.
Even if d and 12e are long, each drain tank 10a, 1
Since the drain flow rate to 0b can be distributed in approximately 1/2,
The pressure loss in the portion can be reduced, and thus, even when the automatic on-off valve fails, delay of the coolant discharge time can be prevented.

Fourth Embodiment (FIG. 4) FIG. 4 is a system diagram showing a fourth embodiment of the present invention.

The basic structure of this embodiment is the same as that of the first embodiment except that the drain pipe 11 and the drain pipe 13 are not integrated, and one drain pipe 11 is independently connected to the drain tank 9. However, the difference is that the other drain pipe 13 is integrated with the overflow pipes 21 and 22 and connected to the drain tank 9. And one of the independent drain pipes 11 has
Two sets of automatic on-off valves 14 (14a, 14
b) and 17 (17a, 17b) are provided in series, and the other drain pipe 13 is provided with two sets of automatic two sets in parallel at the upstream side of the integrated portion (point C) with the overflow pipes 21 and 22. On-off valves 16 (16a, 16b), 41 (41a, 41)
b) are provided in series.

The drain pipe 13 and the overflow pipe 2
1 and 22 (point C), pipe 8 and drain pipe 13
The height difference H1 (m) from the branch point (point D) with respect to the points C to D in the pressure loss of the drain pipe 13 (equivalent to the water head) when it is assumed that draining is performed independently from the drain pipe 13 When the pressure loss up to the point is ΔP1 (m), H1> ΔP1
It is a position that satisfies.

Since other configurations are the same as those of the first embodiment, the same reference numerals as in FIG. 1 are used in FIG. 3 and the description is omitted.

According to the fourth embodiment having such a configuration, similarly to the first embodiment, the automatic on-off valve 14 having the parallel configuration is provided.
a, 14b, 17a, 17b, 16a, 16b, 41
Even if one of the valves a and 41b does not open, the pipe lines of the drain pipes 11 and 13 are reliably conducted to the drain tank 9, and the coolant can be discharged in an emergency or the like. Become. Further, the automatic on-off valves 14a, 14
b, 17a, 17b, 16a, 16b, 41a, 41b
, The coolant can be discharged in a predetermined time even if any of the automatic on-off valves cannot be opened.

Further, since the drain pipe 13 is not integrated with the drain pipe 11 but is integrated with the overflow pipes 21 and 22, these overflow pipes 21 and 22 can also be used as drain pipes, and the number of drain pipes to be installed is reduced. It is also possible to do. Further, since the coolant is discharged to the drain tank 9 by two independent drain pipes 11 and 13, the drain time can be reduced. Further, since the coolant having substantially the same temperature as the coolant in the coolant return pipes 6 and 8 always flows through the overflow pipes 21 and 22, even in the case of an emergency drain at the time of coolant leakage, the overflow pipe is used. Since the coolant at the same temperature as in the normal operation is discharged to the system, the transient of heat to the drain tank nozzle can be reduced.

Further, the height difference H1 (m) between an integrated portion (point C) of the drain pipe 13 and the overflow pipes 21 and 22 and a branch point (point D) of the pipe 8 and the drain pipe 13 is represented by a drain. Of the pressure loss (equivalent to the water head) of the drain pipe 13 assuming that the coolant was discharged from the pipe 13 alone, C
When the pressure loss from point to point D is ΔP1 (m), H
Since the position satisfying 1> ΔP1 is satisfied, when the coolant is discharged from the drain pipe 13 to the pipe 8, the flow rate of the drain does not decrease due to the gas being drawn in from the overflow pipes 21 and 22.

Fifth Embodiment (FIG. 5) FIG. 5 is a system diagram showing a fifth embodiment of the present invention.

The present embodiment has a drain pipe configuration substantially the same as that of the fourth embodiment. However, the drain pipes 13 and 42 are provided at two positions in the coolant return pipe 6 at positions before and after the circulation pump 7.
And integrate these drain pipes 13 and 42 (point E)
After that, they are integrated with the overflow pipes 21 and 22 (point F). Each of these drain pipes 13 and 42 has an automatic on-off valve 16 (16a, 16a) of two parallel arrangements on the upstream side of the integrated part (point F) with the overflow pipes 21 and 22.
b) and 43 (43a, 43b) are provided, respectively, and an automatic on-off valve 4 having two parallel
1 (41a, 41b) are provided. Other configurations are the same as those of the fourth embodiment, and therefore, the same reference numerals as in FIG.

According to the fifth embodiment having such a structure,
By branching the drain pipe 42 on the upstream side of the circulation pump 7 of the pipe 8, an effect that the discharge around the steam generator 5 in which the volume of the coolant becomes large in the secondary cooling system can be performed early is added. .

The installation height of the integrated part (point E) of the drain pipe 13 and the drain pipe 42, and the integrated part of the overflow pipes 21 and 22 after integration of the drain pipes 13 and 42 (point F)
Is set in the same manner as in the fourth embodiment.

Sixth Embodiment (FIG. 6) FIG. 6 is a system diagram showing a sixth embodiment of the present invention.

This embodiment has the same drain pipe configuration as that of the fourth embodiment, except that a gas discharge pipe 44 for opening the atmosphere to the cover gas pipe 30 is branched and connected to the gas discharge pipe 44. The automatic on-off valves 45a and 45b for controlling the emission gas of the base parallel configuration are installed. Other configurations are the same as those in the fourth embodiment, and therefore, the same reference numerals as in FIG. 4 are assigned to FIG. 6 and the description is omitted.

According to the sixth embodiment having such a structure,
The gas flow rate in the cover gas pipe 30 at the time of discharging the coolant can be reduced, and the pressure loss due to the gas flow in the cover gas pipe 30 can be reduced.

That is, the drain pipe 11 connected to the pipe 2 for supplying the coolant and the downstream pipe 8 for returning the coolant
When the coolant is discharged from the drain pipe 13 connected to the drain pipe 9 to the drain tank 9, and the coolant is discharged from the drain pipe 12 connected to the upstream pipe 6 for returning the coolant to another drain tank 10, Gases having the same capacity as the coolant are pushed out from the drain tanks 9 and 10 and transferred to the secondary cooling system.

At this time, if the flow rate of the cover gas from the drain tank 9 is V1 and the flow rate of the cover gas from the drain tank 10 is V2, if the cover gas is not discharged,
The flow rate V3 of the cover gas pipe 30 is

## EQU1 ## V3 = V1 + V2.

On the other hand, in this embodiment, the gas is discharged at the flow rate V4 through the gas discharge pipe 44, so that the gas flow rate V3 flowing through the cover gas pipe 30 is reduced.

## EQU2 ## V3 = V1 + V2-V4, the flow rate of the gas flowing through the cover gas pipe 30 decreases, and the pressure loss due to the gas flow in the cover gas pipe 30 decreases. When the pressure loss of the cover gas pipe 30 is large, the pressure on the secondary cooling system side is low and the pressure on the drain tanks 9 and 10 is high, which causes a decrease in the drain flow rate. Outgassing works in the direction of suppressing a decrease in drain flow rate.

The secondary cooling system, drain tanks 9 and 10
As a result, the pressure difference between the inside of the system and the atmosphere is eliminated, leading to a reduction in the leak rate until the drain is completed.

Seventh Embodiment (FIGS. 7 to 11) This embodiment relates to a coolant drain of a nuclear reactor having a liquid level gauge for measuring the liquid level of the coolant in a drain tank. 7 is a system diagram showing the entire configuration of the drain facility. FIG. 8 is a partially enlarged view showing a mounting configuration of the liquid level gauge to the drain tank, and FIG. 9 is an enlarged view showing a portion G of FIG. FIGS. 10 and 11 show modified examples, which correspond to FIGS. 8 and 9, respectively.

This embodiment exemplifies a case in which the mounting structure of the liquid level gauge is applied to the drain equipment system shown in the first embodiment, and the entire structure of the system is shown in FIG.
The same reference numerals are given and the description is omitted. It is needless to say that this embodiment can be applied to the systems of the second to sixth embodiments.

As shown in FIG. 7, each drain tank 9, 1
Vertically elongated bar-shaped liquid level gauges 50 and 51 are inserted into the insides of the cylinders 0, respectively, and the upper ends of the liquid level gauges 50 and 51 are fixed to the drain tanks 9 and 10 by a similar mounting configuration.
In the following description, a configuration for mounting the liquid level gauge 50 to one drain tank 9 will be described.

As shown in FIG. 8, a nozzle 52 for inserting a liquid level gauge is formed on the upper wall of the drain tank 9 by a cylindrical wall which rises up integrally, and a nozzle flange 53 is provided at an upper end of the nozzle 52. Is formed. The liquid level gauge 50 is fixed to the nozzle flange 53 while being housed in a vertically long cylindrical liquid level gauge sheath 55. That is, the liquid level gauge 50
Has a coil (not shown) inside a vertically long rod-shaped body, and is configured to obtain an electric output according to the liquid level 60 outside the level gauge sheath 55. 57 are protrudingly provided. The level gauge sheath 55 has a vertically long cylindrical shape with an upper end open and a lower end closed, and covers the periphery of the level gauge 50 with a predetermined gap therebetween. A large-diameter flange-shaped lid 54 mounted on the nozzle flange 53 to close the nozzle 52, and a level gauge 50 protruding from a position at a fixed height L above the lid 54.
And a flange 56 capable of abutting and supporting the flange 57 of the liquid crystal display. The joint between the nozzle flange 53 and the lid 54 of the level gauge sheath 55, and the level gauge sheath 56 and the flange 57 of the level gauge 50 are fastened and fixed with bolts or the like in a sealed state, respectively. Area meter 50
The lower end of the level gauge sheath 55 is inserted up to the inner bottom of the drain tank 9.

The joint surface between the nozzle flange 53 and the lid 54 of the level gauge sheath 55 is a boundary 58 between the upper cover gas space in the tank 9 and the external atmosphere. However, an O-ring having good airtightness is provided as a sealing material. The joint surface between the level gauge sheath 56 and the flange 57 of the level gauge 50 is the level gauge sheath 5.
5 is the boundary 59 between the internal space and the outside atmosphere,
Since this boundary 59 is not directly communicated with the inside of the drain tank 9, there is no need for hermeticity during normal use, but in the unlikely event that the level gauge sheath 55 is damaged, the coolant will not be in contact with the level gauge 50. Even if the liquid enters the gap with the gauge 55 and rises, the liquid level gauges are provided with sufficient airtightness to secure a sufficient time until the gas inside the level gauge 55 completely escapes. Both contact surfaces of the flange 56 and the flange 57 of the liquid level gauge 50 are surface-finished.

FIG. 9 shows the width d of the gap between the level gauge 50 and the level gauge sheath 55, and the thickness t of the peripheral wall of the level gauge sheath 55.
In order to explain the details of the above-mentioned and the like, the above-mentioned joint is shown in a further enlarged manner. As shown in FIG.
Even if the level gauge sheath 55 is broken and the above-mentioned coolant enters the gap with the level gauge 50 upward, it flows out from the boundary 59 which is a connection portion with the level gauge 50. Previously, at the protruding portion from the lid 54, which is the attachment portion to the drain tank 9, to the liquid level gauge 50 and the flange 56, which is the connection part with the liquid level gauge 50, so that the coolant is cooled to the freezing point and solidified. The sheath thickness t and the protruding length L corresponding to the gap width d with the liquid level gauge 50 are sufficient so that the temperature of the sheath portion is sufficiently lower than, for example, the sodium freezing point (about 98 ° C.).

Thus, even if the level gauge sheath 55 is damaged, the coolant such as sodium, which has risen in the gap between the level gauge sheath 55 and the level gauge 50, will not pass through the nozzle cover 54 and the liquid level. It freezes between the level gauge sheath and the flange 56 and does not reach the boundary 59 which is a connection portion with the level gauge 50,
Outflow from this boundary 59 is prevented.

That is, according to the present embodiment, the liquid level gauge 5
A gap is formed between the circumference of the cylinder 0 and the level gauge sheath 55, and a seal is provided between the level gauge 50 and the level gauge sheath 55 at a position protruding above the drain tank 9, and the gap is made all around. Since the coolant which enters the gap due to the breakage of the liquid level gauge sheath 55 and rises is set to an upward protruding length which can be cooled down to the freezing point and solidified before flowing out from the seal portion to the outside, the base coolant is It can be prevented from flowing out from the seal part,
This has the effect of ensuring safety.

Next, referring to FIGS. 10 and 11,
A description will be given of a modified example of the mounting configuration of No. 0. FIG. 10 is an enlarged view corresponding to FIG. 8 described above, and FIG.
It is the H section enlarged view of.

As shown in these figures, in this modification, a liquid level gauge, which is a connection section with the liquid level gauge 50, is provided from a nozzle lid 54, which is a part for attaching the liquid level gauge 55 to the drain tank 9. A fin structure 63 is provided on the protruding portion up to the flange 56.
Is provided.

As a result, as compared with the case where the fin structure 63 is not provided, the heat radiation capability of the protruding portion is further improved, and in the unlikely event that the level gauge sheath 55 is damaged, the coolant vapor enters the gap. Even so, it is possible to cool down to the freezing point more quickly and freeze it. For this reason, it is possible to more reliably prevent the coolant from leaking to the outside.

As shown in FIG. 11, in this modification, an O-ring 64 is provided as a sealing material on the connection surface between the liquid level gauge sheath or flange portion 56 and the flange 57 of the liquid level gauge 50.

As a result, the sealing performance at the boundary 59 between the internal space of the liquid level gauge sheath 55 and the external atmosphere is further improved as compared with the case where no sealing material is provided. Therefore, even if the coolant level gauge 55 is damaged and the coolant enters the gap, the leakage of the gas inside the sheath and the rise of the coolant level are further suppressed, and the coolant reaches the solidification point. The effect of promoting a phase change in which the temperature falls and freezes is obtained. For this reason, it is possible to more reliably prevent the coolant from leaking to the outside.

In the above description, O is used as the sealing material.
Although the ring 64 is shown as an example, the same effect can be obtained even with a sheet-shaped packing gasket as long as the sealing property can be maintained.

In the above embodiment, the flange structure is shown as an example of the connection structure between the liquid level gauge 55 and the liquid level gauge 50. However, the same effect can be obtained when a PT screw structure is employed. Can be As a means for improving the sealing performance in this case, the same effect as when an O-ring or a sheet-shaped packing gasket is installed in the flange structure can be obtained by inserting a sealing tape.

Eighth Embodiment (FIG. 12) In this embodiment, a thermometer is installed in a drain tank in order to measure the temperature of a coolant that may flow into the drain tank. FIG. 12 is a system configuration diagram. In this embodiment, the case where the mounting structure of the thermometer is applied to the drain equipment system shown in the first embodiment is also illustrated, and the entire configuration of the system is shown in FIG. And the description is omitted. It is needless to say that this embodiment can also be applied to the systems of the second to sixth embodiments.

As shown in FIG. 12, in this embodiment, thermometers 61 and 62 for measuring the sodium temperature in the drain tanks 9 and 10 are installed in the drain tanks 9 and 10, respectively.

The mounting structure of these thermometers 61 and 62 to the drain tanks 9 and 10 is substantially the same as the mounting structure of the liquid level gauges 50 and 51 of FIGS. 8 to 11 showing the seventh embodiment. is there. That is, the level gauges 50 and 51 described above are used.
Are replaced with thermometers 61 and 62, and the above-mentioned liquid level gauge sheath 55 is replaced with a thermometer sheath.

In the present embodiment, as in the case of the level gauge sheath, the gap between the thermometer sheath and the thermometer is adjusted so that the temperature of the protruding portion of the thermometer sheath sufficiently falls below the sodium freezing point (about 98 ° C.). It is configured to ensure the thickness, thickness and protrusion length.

With such a configuration, even if the thermometer sheath is damaged, the sodium that has entered the sheath is frozen at the relevant portion and reaches the connection between the thermometer body and the thermometer sheath. It does not reach, and is prevented from flowing out.

It should be noted that the thermometers 61 and 6 in the present embodiment
As the mounting configuration 2, all the configurations including the modifications in the seventh embodiment can be applied, and the same effect can be obtained.

Ninth Embodiment (FIGS. 13 and 14) This embodiment is directed to a configuration in which a drive section of an automatic on-off valve installed in a drain pipe is covered with a heat-resistant protective box. FIG. 13 is a sectional view showing the configuration of the present embodiment, and FIG. 14 is a side sectional view of FIG.

As shown in these figures, in this embodiment, the drive section 102b of the automatic on-off valve 102a is covered and protected by a heat-resistant protection box 101a. The heat-resistant protective box 101a is, for example, a rectangular parallelepiped, and
03, a bottom plate 104 and each side plate 105, and the edges of these plates 103, 104, 105 are assembled by being disassembled by a mounting jig 106.

Each top plate 103, bottom plate 104 and side plate 10
Numeral 5 is composed of an outermost plate 107 arranged on the outermost side, an innermost plate 108 arranged inside these with a space therebetween, and a heat insulating material 109 filled therebetween.

According to the present embodiment having such a configuration, assuming that the coolant such as sodium leaks to the outside and the atmosphere temperature becomes high due to the chemical reaction with oxygen in the atmosphere, it is assumed that Since the drive section 102b of the automatic opening / closing valve 102a is insulated and protected by the heat-resistant protective box 101a, the function of the automatic opening / closing valve 102a for discharging the coolant can be maintained.

Further, since the heat-resistant protective box 101a is configured to be disassembled, the drive unit 102 of the automatic on-off valve 102a
b, when inspecting the heat-resistant protective box 101a, etc., it is possible to work efficiently by disassembling and assembling, thereby improving the working efficiency and easily applying to the existing automatic on-off valve. Becomes

Tenth Embodiment (FIGS. 15 and 16) This embodiment also has a configuration in which the drive section of the automatic on-off valve installed in the drain pipe is covered with a heat-resistant protective box. FIG. 15 is a sectional view showing the configuration of the present embodiment, and FIG. 16 is a side sectional view of FIG.

As shown in these figures, the heat-resistant protective box 101b of this embodiment is formed by bending the side plate 103 of the heat-resistant protective box 101a described in the ninth embodiment and forming it into a cylindrical shape. That is, also in the present embodiment, the drive section 102b of the automatic on-off valve 102a is covered and protected by the heat-resistant protection box 101a.
Is configured as a cylindrical body, and includes, for example, a disc-shaped top plate 103 and a bottom plate 104, and a split tubular side plate 105 joined therearound, and these plates 103, 104, 105
Are detachably joined by a mounting jig 106 and assembled.

Top plate 103, bottom plate 104 and side plate 105
As in the case of the ninth embodiment, the outer plate 107 is disposed on the outermost side, the inner plate 108 is disposed on the inner side of the outer plate 107 with a space therebetween, and the heat insulating material 109 filled therebetween is provided.
And is constituted by.

According to the present embodiment, in addition to the same effects as in the ninth embodiment, by making the heat-resistant protective box 101b a cylinder, the atmospheric pressure in the installation chamber when the coolant (sodium or the like) leaks out is reduced. The strength against the rise is increased, and the distance from the outside of the heat-resistant protective box 101b to the drive section 102b is substantially the same in each direction due to the shape thereof, so that the effect of suppressing the temperature difference between the respective sections of the drive section 102b is exhibited.

Eleventh Embodiment (FIGS. 17 to 19) In this embodiment, an opening window is provided in the heat-resistant protective box in the ninth embodiment and the tenth embodiment, and the opening window has heat insulation and elasticity. This is for a configuration with a lid attached.

FIG. 17 shows a ninth embodiment (FIG. 13, FIG. 1).
FIG. 18 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG. 4), and FIG. 18 is a tenth embodiment (FIG. 1).
FIG. 17 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG.

As shown in these figures, the heat-resistant protective boxes 101a and 101b of the present embodiment have an opening window 111 on one side surface 110, and this opening window 111 has a heat insulating and extensible, for example, bellows-like shape. A closing lid 112 is provided, and the closing lid 112 is provided to be openable and closable along a guide groove 114. The closing lid 112 always contracts and the opening window 11 is closed.
1 is opened, and extends along the guide groove 114 in an emergency, so that the opening window 111 is closed confidentially.

FIGS. 19 (a), (b) and (c) show different construction examples (112a, 1) of the closing lid 112, respectively.
12b, 112c).

The closing lid 112a shown in FIG. 19A has a two-layer structure including a lid main body 15 made of a shape memory metal and a heat insulating material 113, and is set in a contracted state under a normal ambient temperature environment. The bellows has a contracted shape. When the ambient temperature becomes high and the temperature exceeds a predetermined temperature, the closing lid 112a extends along with the heat insulating material 113 along the groove 114, closes the opening window 111, and enters the heat-resistant protective boxes 101a and 101b. Acts to suppress the invasion of heat.

The closing lid 112b shown in FIG. 19B has a three-layer structure as a whole, and includes two-layer lid bodies 15a and 15b in which dissimilar metals A and B are joined, and a heat insulating material 113. I have. The lid body 115a of the metal A facing the outside of the heat-resistant protective box of the closing lid 112b is made of a material having a higher coefficient of thermal expansion than the lid body 115b of the metal B facing the inside. Has a contracted bellows shape. Then, when the ambient temperature becomes high, it extends along the above-mentioned groove 114 together with the heat insulating material 113, closes the opening window 111, and suppresses the intrusion of heat into the heat-resistant protective boxes 101a, 101b. Do.

The closing lid 112c shown in FIG. 19C is composed of a lid body 116 made of a metal bellows and a heat insulating material 113 joined to the inner surface of the heat-resistant protective box.
Under a normal atmosphere temperature environment, the bellows shape is contracted, and when the atmosphere temperature becomes high, the thermal expansion of the gas inside the lid body 116 made of bellows causes the heat insulating material along the groove 114. It extends along with 113, closes the opening window 111, and acts to suppress the intrusion of heat into the heat-resistant protective box.

According to the present embodiment having the above configuration,
In the event that a coolant such as sodium leaks to the outside and the ambient temperature becomes high, the opening window 111 automatically closes the closing lid 112 (112a, 112b, 112) due to a temperature change.
c) and is closed by the heat-resistant protective box 101 (101a, 101a,
101b) has an effect of suppressing the invasion of heat into the inside.
During normal operation, the heat-resistant protective box 101 (101a, 1
01b) is open, the heat received by the heat conduction from the automatic on-off valve can be released to the outside of the heat-resistant protective box, and the drive unit can be simplified without disassembling the heat-resistant protective box. This makes it possible to perform a periodic inspection.

Twelfth Embodiment (FIG. 20) This embodiment is also the same as the ninth and tenth embodiments except that the heat-resistant protective box is provided with an opening window.
Unlike the embodiment, the heat-insulating closing lid attached to the opening window is of a normally-open type fixed by a fixing jig that closes by detecting high heat. FIG. 20 is a perspective view showing the heat-resistant protective box of the present embodiment.

As shown in FIG. 20, in this embodiment, an opening window 111 is provided on one side surface 110 of the heat-resistant protective box 101, and a closing lid 112 is attached to an upper end of the opening window 111. The closing lid 112 has a configuration in which a heat insulating material 113 is laid on the inner surface, and the closing lid 112 is normally fixed to an open state by a fixing jig 127.

[0120] The fixing jig 127 has a function of being broken by a heat effect when the temperature exceeds a predetermined temperature, and is in a connected state under a normal ambient temperature environment. When the ambient temperature becomes high due to the leakage, the opening lid 111 is broken and the closing lid 112 is opened. Therefore, the closing lid 112 is dropped downward with the mounting portion of the opening window 111 as a fulcrum, and the opening window 111 is closed.

Therefore, according to the present embodiment, when the ambient temperature becomes high due to the external leakage of the coolant, the fixing jig 127 is broken by the temperature rise, and the closing lid 112 closes the opening window 111. And heat-resistant protective box 1
In addition to suppressing the intrusion of heat into the inside of the heat-resistant protective box 101 during normal operation, the heat received by the heat conduction from the automatic on-off valve can be released to the outside of the heat-resistant protective box by the normally open state, without disassembling the heat-resistant protective box 101 However, such an effect is obtained that a simple inspection of the drive unit becomes possible.

Thirteenth Embodiment (FIGS. 21 to 23) In this embodiment, an opening window is provided in the heat-resistant protective box in the ninth embodiment and the tenth embodiment, and a net is installed in the opening window. Is coated with a foaming paint having heat insulation performance.

FIG. 21 shows a ninth embodiment (FIG. 13, FIG. 1).
FIG. 22 is a perspective view showing a case where this embodiment is applied to the heat-resistant protective box 101a of FIG. 4), and FIG. 22 is a tenth embodiment (FIG. 1).
FIG. 17 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG. FIG. 23 is an enlarged view showing the configuration of the wire net 117. As shown in FIG.

As shown in these figures, the heat-resistant protective boxes 101a and 101b of this embodiment have an opening window 111 on one side surface 110, and a wire net 117 is provided in the opening window 111. A foaming paint 118 is applied to the surface of the wire mesh 117. The foaming paint 118 foams when the ambient temperature rises, and expands from the thickness before foaming to about several tens times to close the opening window. , Functioning as a heat insulator.

According to the present embodiment, when the coolant such as sodium leaks to the outside and the ambient temperature becomes high, the foaming paint 118 applied to the wire mesh 117 foams and the opening window 111 is opened. Alternatively, the entire heat-resistant protective box can be closed to prevent heat from entering the heat-resistant protective box, and during normal operation, heat transmitted by heat conduction from the valve can be released outside the heat-resistant protective box. Effects such as a simple inspection of the drive unit are possible without disassembling the protective box.

Fourteenth Embodiment (FIGS. 24 and 25) In this embodiment, the protective box itself of the automatic on-off valve is covered with a net, and the net is coated with a foaming paint having heat insulating properties.

FIG. 24 shows a ninth embodiment (FIG. 13, FIG. 1).
FIG. 25 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG. 4), and FIG. 25 is a tenth embodiment (FIG. 1).
FIG. 17 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG.

As shown in these figures, in this embodiment, the entire heat-resistant protective boxes 101a and 101b are formed by a wire mesh 117, and the surface of the wire mesh 117 has a thirteenth aspect.
As in the embodiment, a foaming paint 118 is applied. The foaming paint 118 foams when the ambient temperature rises, expands to about several tens of times the thickness before foaming, closes the opening, and has the function of functioning as a heat insulating material.

Therefore, according to the present embodiment, when the ambient temperature becomes high due to external leakage of the coolant, the foaming paint 118 applied to the wire mesh 117 foams, and the entire heat-resistant protective boxes 101a and 101b become full. Closed from the outside,
Intrusion of heat into the heat-resistant protective boxes 101a and 101b is suppressed. Also, during normal operation, heat transmitted by heat conduction from the valve is released to the outside of the heat-resistant protection boxes 101a and 101b,
Further, there is an effect that the drive unit can be easily inspected without disassembling the heat-resistant protective boxes 101a and 101b.

Fifteenth Embodiment (FIG. 26) This embodiment relates to the support structure of the heat-resistant protective box of each of the above embodiments, and FIG. 26 is a sectional view showing this support structure.

As shown in FIG. 26, in this embodiment, a support device 119 is provided in the building 33, and this support device 119 is provided.
The drive unit 102b of the automatic on-off valve 102a is connected to the control unit 102 via a support pipe 122. This automatic on-off valve 102
The heat-resistant protective box 101 covering the drive unit 102b of FIG. 1A is connected to a support pipe 122 via a mounting jig 121, whereby the load of the heat-resistant protective box 101 is supported by the support device 119. The support pipe 122 is a heat-resistant protective box 1
01 is inserted through the through hole 122.

According to the present embodiment configured as described above, by supporting the load of the heat-resistant protection box 101 by the support device 119, the load of the heat-resistant protection box 101 is not applied to the automatic opening / closing valve 102a. The occurrence of valve failure due to the application of a large load can be suppressed, whereby the reliability of the operation function of the automatic on-off valve 102a can be improved. Further, since the heat-resistant protective box 101 is connected to the valve side via the mounting jig 121, it moves following the displacement of the automatic opening / closing valve 102a due to thermal expansion of the secondary cooling system piping. Therefore, the area of the through-hole 122 such as the support pipe 120 that penetrates the heat-resistant protective box 101 can be minimized, and the effect of suppressing the intrusion of heat from the penetrating portion is achieved.

Sixteenth Embodiment (FIGS. 27 to 29) This embodiment relates to a structure for supporting a heat-resistant protective box.

FIG. 27 shows a ninth embodiment (FIG. 13, FIG. 1).
FIG. 28 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG. 4), and FIG. 28 is a tenth embodiment (FIG. 1).
FIG. 17 is a perspective view showing a case where the present embodiment is applied to the heat-resistant protective box 101a of FIG. FIG. 29 shows an automatic on-off valve 1
It is a side view including 02a.

As shown in FIGS. 27 and 28, in this embodiment, the heat-resistant protective boxes 101a and 101b are mounted on the frame 123, and the load of the heat-resistant protective box 101 is supported by the frame 123. As shown in FIG. 29, a part of the automatic opening / closing valve 102a penetrates the heat-resistant protective boxes 101a and 101b (see FIG. 26 and the like), and a heat insulating material is laid inside the penetrating portion. It is covered by a heat-resistant skirt 128.

According to the present embodiment having such a configuration, the load of the heat-resistant protective boxes 101a and 101b does not need to be applied to the automatic on-off valve 102a, and the occurrence of valve failure due to the application of an extra load is suppressed. Automatic opening and closing valve 10
The reliability of the operation function of 2a is improved. Further, the penetration of the automatic opening / closing valve 102a into the heat-resistant protection boxes 101a and 101b is covered with a heat-resistant skirt 128 in which a heat insulating material is laid, so that the effect of suppressing heat intrusion from the penetrations is exerted. .

Seventeenth Embodiment (FIG. 30) In this embodiment, a heat insulating material and the like are added to the support pipe and the mounting jig of the heat-resistant protective box shown in the fifteenth embodiment (FIG. 26). FIG. 30 is a sectional view showing the structure.

As shown in FIG. 30, in this embodiment, the heat-resistant protective box 101 is provided with a support device 119 for the automatic on-off valve 102a.
A heat insulating material 123 is provided inside a hollow support pipe 120 penetrating the heat-resistant protective box 101, and a mounting jig 121 is covered with an exterior plate 124.
The inside of the exterior plate 124 is reinforced by a heat insulating material 125.

According to this embodiment, the heat insulating material 12 is provided inside the support pipe 120 penetrating the heat-resistant protective box 101.
By providing 3, it is possible to suppress the convective heat transfer in the hollow support pipe 120, and to reinforced the periphery of the through-hole 122 with the heat insulating material 125, so that heat input into the heat-resistant protective box 101 is possible. Is suppressed.

Eighteenth Embodiment (FIG. 31) In this embodiment, in addition to the structure shown in the seventeenth embodiment (FIG. 30), a heat insulating material is further added to the drive section of the automatic on-off valve. FIG. 31 is a sectional view showing the structure.

In the present embodiment, as shown in FIG.
In addition to the configuration of No. 0, the drive unit 102 b of the automatic on-off valve 102 a covered with the heat insulating protection box 101 is covered with the heat insulating material 126. The automatic opening / closing valve 102a is provided with an automatic opening / closing valve protection section 102c, and the surface of the automatic opening / closing valve protection section 102c is whitened or polished.

According to the present embodiment having such a structure, by covering the drive section 102b with the heat insulating material 126, the heat resistance of the automatic opening / closing valve 102a can be improved and the surface of the protection section 102c can be whitened or polished. By doing so, the radiant heat transfer in the heat-resistant protective box 101 is suppressed in response to an increase in the ambient temperature when the coolant such as sodium leaks from the outside, so that the effect of slowing down the temperature rise in the protection portion 102c is achieved.

Nineteenth Embodiment (FIG. 32) This embodiment relates to a cable for driving an automatic on-off valve. FIGS. 32 (a) and (b) show different cables according to this embodiment. FIG.

In the first example shown in FIG. 32A, the cable for driving the automatic on-off valve is a heat-resistant cable 129, and the outside of the heat-resistant cable 129 is covered with a heat insulating material. .

In the second example shown in FIG. 32B, the outside of a similar heat-resistant cable 129 is a conduit (conduit) 13.
1 covered.

According to this embodiment having such a configuration, even when the ambient temperature becomes high due to external leakage of the coolant such as sodium, the heat-resistant cable 130 is covered with the heat insulating material 130 or the conduit 131. Therefore, the heat-resistant cable 129 is reliably protected, the function of the cable is not impaired, and the function of the automatic on-off valve 102a is maintained.

[0147]

As described above in detail, according to the present invention, in the cooling system of a nuclear reactor, even if a coolant leaks, the coolant can be reliably discharged to the drain tank. The flow resistance of the drain pipe and the cover gas pipe and the reduction of the drain flow rate due to the entrainment of the gas can be effectively suppressed, the drain is terminated early, and the valve drive unit responds to the rise in the ambient temperature due to the chemical reaction of the coolant. Can be properly protected. Therefore, by improving the reliability of the drain function and terminating the drain quickly and reliably, effects such as a significant reduction in corrosion thinning of the liner plate can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a secondary cooling system in a drain facility of a fast reactor as a first embodiment of the present invention.

FIG. 2 is a system diagram showing a second embodiment of the present invention.

FIG. 3 is a system diagram showing a third embodiment of the present invention.

FIG. 4 is a system diagram showing a fourth embodiment of the present invention.

FIG. 5 is a system diagram showing a fifth embodiment of the present invention.

FIG. 6 is a system diagram showing a sixth embodiment of the present invention.

FIG. 7 is a system diagram showing a seventh embodiment of the present invention.

FIG. 8 is a partially enlarged view showing a mounting configuration of a liquid level gauge to a drain tank in FIG. 7;

FIG. 9 is an enlarged view extracting and showing a G part in FIG. 8;

FIG. 10 is a view showing a modification of the seventh embodiment and corresponding to FIG. 8;

FIG. 11 is an enlarged view showing a portion H extracted from FIG. 10;

FIG. 12 is a system diagram showing an eighth embodiment of the present invention.

FIG. 13 is a sectional view showing a ninth embodiment of the present invention.

FIG. 14 is a side sectional view of FIG. 13;

FIG. 15 is a sectional view showing a tenth embodiment of the present invention.

FIG. 16 is a side sectional view of FIG. 15;

FIG. 17 is a perspective view showing a configuration example of an eleventh embodiment of the present invention.

FIG. 18 is a perspective view showing another configuration example of the eleventh embodiment.

FIGS. 19 (a), (b) and (c) show the eleventh embodiment, respectively.
FIG. 2 is an enlarged view showing a specific configuration example of the embodiment.

FIG. 20 is a perspective view showing a twelfth embodiment of the present invention.

FIG. 21 is a perspective view showing a configuration example of a thirteenth embodiment of the present invention.

FIG. 22 is a perspective view showing another configuration example of the thirteenth embodiment.

FIG. 23 is an enlarged view showing the configuration of the wire mesh of FIGS. 21 and 22.

FIG. 24 is a perspective view showing a configuration example of a fourteenth embodiment of the present invention.

FIG. 25 is a perspective view showing another configuration example of the fourteenth embodiment.

FIG. 26 is a sectional view showing a fifteenth embodiment of the present invention.

FIG. 27 is a perspective view showing a configuration example of a sixteenth embodiment of the present invention.

FIG. 28 is a perspective view showing another configuration example of the sixteenth embodiment.

FIG. 29 is a side view showing a configuration including an automatic on-off valve corresponding to FIGS. 27 and 28;

FIG. 30 is a sectional view showing a seventeenth embodiment of the present invention.

FIG. 31 is a sectional view showing an eighteenth embodiment of the present invention.

FIGS. 32 (a) and (b) are configuration diagrams each showing a cable according to a nineteenth embodiment of the present invention.

FIG. 33 is a system configuration diagram showing a conventional example.

FIG. 34 is a schematic configuration diagram showing a reactor building.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Intermediate heat exchanger 2 Pipe 3 Header 4 minute pipe 5 Steam generator 6 Pipe 7 Circulation pump 8 Pipe 9,10 Drain tank 10a, 10b Drain tank 11,12,13 Drain pipe 12d, 12e Drain pipe 12f Lines) 14, 15, 16, 17, 18 Automatic on-off valves 14a, 14b, 15a, 15b, 16a, 16b, 1
7a, 17b, 18a, 18b, 18c, 41a, 41
b, 43a, 43b, 45a, 45b Automatic on-off valve (valve element) 19 Overflow column 20 Overflow pipe 21, 22 Overflow pipe 23 Air cooler 23a Heat transfer pipe 24 On-off valve 25 Inflow-side bypass pipe 26 On-off valve 27 Outflow-side bypass pipe 28 On-off valve 29, 30 Cover gas pipe 31 Sodium equipment 32 Sodium pipe 32 Pipe 33 Building 34 Sleeve 35 Floor surface 36 Insulation material 37 Liner 38 Lid 42 Drain pipe 44 Gas discharge pipe 50, 51 Level gauge 52 Nozzle 53 Nozzle flange 54 Lid 55 Level gauge sheath 56 Level gauge sheath flange 57 Flange 58, 59 Boundary 60 Level level 61, 62 Thermometer 63 Fin structure 64 O-ring 101a Heat-resistant protective box 101b Outside heat-resistant protective box 102a Automatic open / close valve 102b Drive unit 103 Top board 04 Bottom plate 105 Side plate 106 Mounting jig 107 Exterior plate 108 Interior plate 109 Insulating material 110 One side surface 111 Open window 112, 112a, 112b, 112c Closing lid 114 Guide groove 115a, 115b, 116 Lid body 117 Wire mesh 118 Foaming paint 119 Support Apparatus 120 Support pipe 121 Mounting jig 122 Support pipe 123 Heat insulating material 124 Exterior plate 125 Heat insulating material 126 Heat insulating material 127 Fixing jig 128 Heat resistant skirt 129 Heat resistant cable 130 Heat insulating material 131 Conduit (electric conduit)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G21D 1/00 G21D 1/00 E (72) Inventor Maki Ikeda 2-1-1 Shiraki, Tsuruga-shi, Fukui Nuclear Fuel (72) Inventor Takenori Nakamura 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture In-house Toshiba Yokohama Office (72) Inventor Masahiko Kobayashi 8 Shin-Sugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Address Toshiba Yokohama Office (72) Inventor Nobuyuki Tanaka 8 Shinsugitacho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Yokohama Office

Claims (15)

[Claims] 1. A coolant drain facility provided in a coolant distribution system of a nuclear reactor using liquid metal as a coolant, wherein the coolant is discharged from a device or a pipe of the system to a drain tank by a drain pipe, When the drain pipe is provided with an automatic opening / closing valve that is opened in an emergency, the automatic opening / closing valve is configured as a set of a plurality of parallel opening / closing valves, and a plurality of the automatic opening / closing valves are arranged in the drain pipe in series. A coolant drain system for a nuclear reactor. 2. A coolant drain facility provided in a coolant distribution system of a nuclear reactor using liquid metal as a coolant, wherein the coolant is discharged from a device or a pipe of the system to a drain tank by a drain pipe, When the drain pipe is provided with an automatic opening / closing valve that is opened in an emergency, the automatic opening / closing valve is configured as a set of a plurality of automatic opening / closing valves, and a plurality of the automatic opening / closing valves are arranged in parallel with the drain pipe. A coolant drain system for a nuclear reactor. 3. The coolant drain facility for a nuclear reactor according to claim 1, wherein the drain pipes are integrated at an outlet position of an automatic opening / closing valve arranged near the drain tank and connected to one drain tank or integrated. A coolant drain facility for a nuclear reactor, wherein each of the coolant drain facilities is connected to a separate drain tank. 4. The coolant drain facility for a nuclear reactor according to claim 3, wherein the drain pipes are connected to different drain tanks without being integrated at an outlet position of an automatic opening / closing valve arranged near the drain tank. 3. The coolant drain facility for a nuclear reactor according to claim 1, wherein the drain pipes that are not integrated are connected to each other by a conduit at a position downstream of the automatic on-off valve, and another automatic on-off valve is provided in the conduit. 5. The coolant drain facility for a nuclear reactor according to claim 1, wherein two drain pipes hanging from drain nozzles of equipment having different coolant distribution systems or pipes are connected by a pipe integration unit. Integrate and connect to the drain tank. The coolant discharge of one of the two drain pipes ends first. The difference in elevation from the drain nozzle to the pipe integration part of one of the drain pipes is terminated. A coolant drain facility for a nuclear reactor, wherein the pressure loss is greater than a pressure loss (equivalent to a water head) when the coolant is continuously discharged from the drain nozzle of the other drain pipe to the pipe integration portion. 6. The coolant drain facility for a nuclear reactor according to claim 1, wherein three or more drain pipes hanging from drain nozzles of equipment or pipes having different coolant distribution systems are connected to a pipe integration unit. The drainage of one or more of these drain pipes from which the coolant discharge ends before the difference in elevation from the drain nozzle to the pipe integration part is terminated. A coolant drain facility for a reactor, wherein the pressure loss is greater than a pressure loss (equivalent to a water head) when the coolant is continuously discharged from the drain nozzle of the other drain pipe to the pipe integration part. 7. The coolant drain facility for a nuclear reactor according to claim 1, wherein the pipe to which the drain pipe is connected is configured such that surplus coolant in a system through which the coolant flows is always supplied to the drain tank. A coolant drain facility for a nuclear reactor, which is an overflow pipe for causing overflow. 8. The coolant drain facility for a nuclear reactor according to claim 1, wherein said coolant is supplied to a device, a pipe, or a drain tank of a coolant distribution system together with an emergency discharge of said coolant to said drain tank. A coolant drain facility for a nuclear reactor, comprising a pipe and an automatic on-off valve for releasing a cover gas from the equipment, the pipe or the drain tank. 9. The coolant drain facility for a nuclear reactor according to claim 1, wherein the drain tank includes a liquid level gauge for measuring a liquid level of the coolant stored therein. The liquid level gauge is covered with a liquid level gauge sheath, inserted through a nozzle section provided on an upper wall of the drain tank through the liquid level gauge sheath, and the liquid level gauge is provided around the liquid level gauge. A gap is formed between the level gauge sheath and the level gauge and the level gauge sheath have a sealing portion at a position protruding above the drain tank, and the gap is
The upper protrusion length is set such that the coolant that enters the gap due to breakage of the level gauge sheath and rises is cooled down to the solidification point and solidified before flowing out of the seal portion to the outside. Refrigerant coolant drain equipment. 10. The coolant drain installation for a nuclear reactor according to claim 1, wherein the drain tank includes a thermometer for measuring a temperature of a coolant stored in the drain tank. The thermometer is covered with a thermometer sheath, inserted into a nozzle portion provided on the upper wall of the drain tank through the thermometer sheath, and provided with a gap between the thermometer sheath and the thermometer around the thermometer. And the thermometer and the thermometer sheath have a seal portion at a position protruding above the drain tank, and the gap invades the gap due to breakage of the liquid level gauge sheath. A coolant drain facility for a nuclear reactor, wherein an ascending coolant is set to have an upwardly protruding length sufficient to solidify by lowering its temperature to a freezing point before flowing out of the seal portion to the outside. 11. The coolant drain equipment for a nuclear reactor according to claim 1, wherein a drive unit of an automatic on-off valve installed in each drain pipe is covered with a heat-resistant protective box. Refrigerant coolant drain equipment. 12. The coolant drain facility for a nuclear reactor according to claim 11, wherein an opening window is provided in the heat-resistant protective box, and a closing lid having heat insulation and elasticity is attached to the opening window. Furnace coolant drain equipment. 13. The coolant drain system for a nuclear reactor according to claim 11, wherein an opening window is provided in the heat-resistant protective box, and a heat-insulating closing lid is attached to the opening window, and the closing lid is provided by high-heat sensing. A coolant drain facility for a nuclear reactor, wherein the coolant drain facility is a normally open type fixed by a fixing jig that closes. 14. The coolant drain facility for a nuclear reactor according to claim 11, wherein an opening window is provided in the heat-resistant protective box, a net is installed in the opening window, and a foam type paint having heat insulation performance is applied to the net. A coolant drain facility for a nuclear reactor. 15. A coolant drain installation for a nuclear reactor according to claim 11, wherein the protective box of the automatic on-off valve is covered with a net, and the net is coated with a foaming paint having heat insulating properties. Furnace coolant drain equipment.