JP3605004B2 - Reactor coolant drain facility - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
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 particularly to a nuclear reactor applied to a primary cooling system, a secondary cooling system, an auxiliary system, and the like Related to a coolant drain facility.
[0002]
[Prior art]
In a liquid metal-cooled reactor, for example, in a fast reactor, a primary coolant such as liquid sodium passing through a reactor core is heat-exchanged with a secondary coolant such as liquid sodium in an intermediate heat exchanger. Heat is 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 the event of an emergency such as leakage of the coolant in the system piping.
[0003]
FIG. 33 shows an example of a conventional coolant drain facility applied to a secondary cooling system of a fast reactor. That is, an intermediate heat exchanger 1 is provided in the secondary system of the illustrated fast reactor, and the secondary coolant exchanged with the primary coolant in the intermediate heat exchanger 1 passes through the pipe 2 for feeding. The steam is sent to the header 3 and sent from the header 3 to 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 that has been 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 to a circulation pipe 8, the intermediate heat exchanger. It is to be returned to 1.
[0004]
Drain tanks 9 and 10 for storing the secondary coolant are connected to the respective pipes 2, 6 and 8 via drain pipes 11, 12 and 13 branched from the bottoms of the pipes 2, 6 and 8. Automatic opening / closing valves 14 to 18 are provided in the middle of the drain pipes 11, 12, and 13, respectively. Then, in an emergency or the like, the automatic opening / closing valves 14 to 18 are opened, and the secondary coolant in the secondary cooling system is automatically discharged into the drain tanks 9 and 10.
[0005]
In addition, the circulation pump 7 has an overflow space 7a that can accommodate an excess secondary coolant, and the overflow space 7a is provided in an overflow column 19 for receiving a secondary coolant arranged near the circulation pump 7. It is connected via an overflow pipe 20. Thus, when the liquid level of the secondary coolant in the circulation pump 7 becomes equal to or higher than a predetermined liquid level, excess secondary coolant is sent to the overflow column 19 through the overflow pipe 20. Overflow pipes 21 and 22 are provided in the overflow column 19 and the steam generator 5, respectively, and these overflow pipes 21 and 22 are connected to one drain tank 9.
[0006]
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 enters the drain tank 9 via the overflow pipes 21 and 22. The liquid is discharged 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.
[0007]
By the way, in such a secondary cooling system, an air cooler 23 is provided in case a load side such as a turbine trips. The air cooler 23 cools the secondary coolant by exchanging heat 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 on 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.
[0008]
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, and the secondary coolant is supplied to the air cooler 23 through the inflow side bypass pipe 25 and the outflow side bypass pipe 27. Flows, and the secondary coolant exchanges heat with air in the heat transfer tube 23a of the air cooler 23, whereby heat generated in the core is finally exhausted.
[0009]
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.²A cover having a pressure of is sealed, so that when the coolant is drained, the gas pushed out from the drain tank side can be transferred to the secondary cooling system side.
[0010]
Since the secondary cooling system devices and piping described above are generally installed in an air atmosphere, if sodium or the like as the secondary cooling material leaks to the outside, chemical reaction with oxygen in the atmosphere will occur. It is possible that a high temperature could be generated to cause a fire and a fire. Therefore, if a leak occurs, the automatic opening / closing valves 14 to 18 installed in the drain pipes 11 to 13 are opened to prevent the effect of the fire from spreading due to the continuation of the leak, and the drain tanks 9 and 10 are opened. The secondary coolant is sent urgently.
[0011]
In addition, a liner (a steel pan) is provided on the inner surface of the floor of the building where the devices and piping are installed so that the leaking sodium can be stored or transferred.
[0012]
FIG. 34 illustrates a configuration of a building provided with a liner. As shown in FIG. 34, a sodium pipe 32 connected to a sodium device 31 such as the generator is inserted through a sleeve 34 into a building 33, and is connected to a floor 35 on which these pipes 32 face. A liner 37 is provided via a heat insulating material 36. The end of the liner 37 is covered with a lid 38 or the like.
[0013]
[Problems to be solved by the invention]
If any of the automatic opening / closing valves 14 to 18 cannot be opened when the cooling system equipment or piping is damaged, the relevant part cannot achieve the function of stopping the leakage due to drainage, and the leaked coolant will remain in the liner for a long time. Since the liner 37 falls down on the surface of the liner 37 due to the chemical reaction of the steel material of the coolant generated at this time, it is necessary to use a thick steel material for the liner 37 in consideration of the corrosion thinning. Was.
[0014]
Further, depending on the size of the leak, the ambient temperature reaches several hundred degrees Celsius due to the chemical reaction between the coolant and oxygen in the air, so that a valve driving device (not shown) for driving the automatic on-off valves 14 to 18 is provided. It is possible that the temperature exceeds the heat-resistant temperature (generally 100 ° C. to 200 ° C.), thereby causing a problem in opening and closing the automatic on-off valves 14 to 18.
[0015]
Furthermore, 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 pipe and the flow resistance of the cover gas flowing from the drain tank to the cooling system instead of the coolant. Therefore, it was necessary to install a large-diameter drain pipe and a cover gas pipe. In addition, 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 side that has been finished. However, there is a possibility that the remaining drain flow becomes a two-phase flow and the drain time is extended.
[0016]
The present invention has been made in view of such circumstances, and an object of the present invention is to ensure that drainage can be quickly performed in the event of an emergency such as leakage of a coolant, thereby reducing the amount of corrosion reduction of the liner plate. It is an object of the present invention to provide a coolant drain facility for a nuclear reactor, which can suppress the occurrence of water.
[0017]
[Means for Solving the Problems]
In the cooling system of the nuclear reactor, the present invention provides a method of draining the drain pipe and the cover gas pipe by installing a plurality of automatic opening / closing valves for the drain pipe in order to reliably drain the coolant when leakage occurs. The drain function is effectively prevented by suppressing the resistance and reducing the flow rate of the drain due to gas entrainment, terminating the drain at an early stage, and properly protecting the valve drive unit against an increase in the ambient temperature due to the chemical reaction of the coolant. The main point is to improve the reliability of the reactor and to quickly and surely terminate the drain, thereby significantly reducing the corrosion thinning of the liner plate, and improving the reliability and economy of the reactor.
[0018]
That is, the invention of claim 1 is provided in a coolant distribution system of a nuclear reactor using liquid metal as a coolant, and a coolant drain facility for discharging the coolant from a device or a pipe of the system to a drain tank through a drain pipe. An automatic on-off valve that is opened in an emergency in the drain pipe, wherein the automatic on-off valve is configured as a set of a plurality of parallel on-off valves, and a plurality of sets of the automatic on-off valves are provided on the drain pipe. , Arranged in series.
[0019]
The invention according to claim 2 is a coolant drain facility that is provided in a coolant distribution system of a reactor using liquid metal as a coolant and discharges the coolant from a device or a pipe of the system to a drain tank through 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 serial opening / closing valves, and a plurality of the automatic opening / closing valves are provided in the drain pipe in parallel. It is characterized by being arranged in.
[0020]
According to a third aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the first or second aspect, the drain pipes are integrated at an outlet position of an automatic on-off valve arranged near the drain tank and connected to one drain tank, Alternatively, they are connected to different drain tanks without being integrated.
[0021]
According to a fourth aspect of the present invention, there is provided the coolant drain system for a nuclear reactor according to the third aspect, wherein the drain pipes are connected to different drain tanks without being integrated at an outlet position of an automatic on-off valve arranged near the drain tank. In the above structure, 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.
[0022]
According to a fifth aspect of the present invention, in the 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 having different coolant distribution systems or pipes are integrated. The drainage of the coolant is terminated earlier than the drainage of one of the two drain pipes. The difference in height from the drain nozzle to the pipe integration part is delayed. The pressure loss (equivalent to the water head) during continuous discharge of the coolant from the drain nozzle of the other drain pipe to the pipe integration part.
[0023]
According to a sixth aspect of the present invention, in the coolant drain facility 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 having different coolant distribution systems or pipes are provided. The drains are integrated by the integration part and connected to the drain tank, and the difference in elevation from the drain nozzle to the pipe integration part of one or more drain pipes of which drainage of coolant ends first is delayed. The pressure loss (equivalent to the water head) when the coolant is continuously discharged from the drain nozzle of the other drain pipe to the pipe integration part of the other drain pipe which is completed at the same time is set to be larger.
[0024]
According to a seventh aspect of the present invention, in the coolant drain facility for a nuclear reactor according to any one of the first to sixth aspects, the pipe to which the drain pipe is connected always drains excess coolant in a system through which the coolant flows. It is an overflow piping for overflowing into the tank.
[0025]
According to an eighth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to any one of the first to seventh aspects, an emergency operation of the coolant to the drain tank is performed in equipment, piping or a drain tank of a coolant distribution system. A piping and an automatic opening / closing valve for releasing the cover gas from the device, the piping or the drain tank together with the discharge are provided.
[0026]
According to a ninth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to any one of the first to eighth aspects, the drain tank has a liquid level for measuring a liquid level of the coolant stored therein. The level gauge is covered with the level gauge sheath, and is inserted and installed in the nozzle portion provided on the upper wall of the drain tank through the level gauge sheath, and is provided around the level gauge. A gap is formed between the level gauge sheath and the level gauge and the level gauge sheath each have a seal portion at a position protruding above the drain tank, and the gap is an emergency liquid level. The length of the upwardly projecting coolant is set such that the coolant that enters the gap due to breakage of the surface gauge sheath and rises is cooled to the freezing point and solidified before flowing out of the seal portion to the outside.
[0027]
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 is provided with a thermometer for measuring a 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 placed between the thermometer sheath around the thermometer. 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. The upwardly protruding length is set so that the temperature of the coolant rising to the solidification point is lowered and solidified before flowing out of the seal portion to the outside.
[0028]
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 covered with a heat-resistant protective box. It is characterized by.
[0029]
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. I do.
[0030]
According to a thirteenth aspect of the present invention, in the coolant drain system 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. It is a normally open type fixed by a fixing jig that closes upon sensing.
[0031]
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, a net is installed in the opening window, and the foam has a heat insulating performance in the net. Is applied.
[0032]
According to a fifteenth aspect of the present invention, in the coolant drain facility for a nuclear reactor according to the eleventh aspect, the protection 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. I do.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a coolant emergency drain facility for a nuclear reactor according to the present invention will be described below with reference to FIGS.
[0034]
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. The structure of the building is the same as that shown in FIG.
[0035]
In this embodiment, a heat exchanger 1 for performing heat exchange with a primary coolant flowing through a primary cooling system (not shown) of the fast reactor is provided, and the secondary heat exchanged with the primary coolant by the intermediate heat exchanger 1 is provided. The coolant is sent to the header 3 through the feed pipe 2, and is sent from the header 3 to 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 the heat exchange in the steam generator 5 is sent to the circulation pump 7 through the pipe 6 on the outlet side, and from the circulation pump 7 to the intermediate heat exchanger 1 through the pipe 8 for reflux. Will be returned.
[0036]
Further, the circulation pump 7 has an overflow space 7a that can accommodate an excess secondary coolant, and the overflow space 7a is provided in an overflow column 19 for receiving a secondary coolant arranged near the circulation pump 7. It is connected via an overflow pipe 20. Thus, when the liquid level of the secondary coolant in the circulation pump 7 becomes equal to or higher than a predetermined liquid level, excess secondary coolant is sent to the overflow column 19 through the overflow pipe 20. The overflow column 19 and the steam generator 5 are provided with overflow pipes 21 and 22, respectively. The overflow pipes 21 and 22 are connected to one drain tank 9.
[0037]
Thereby, 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 drain tank 9 through the overflow pipes 21 and 22. The secondary coolant in the steam generator 5, the overflow column 19, and the circulation pump 7 is maintained at a predetermined liquid level.
[0038]
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 exchanging heat 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 on 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.
[0039]
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, and the secondary coolant is supplied to the air cooler 23 through the inflow side bypass pipe 25 and the outflow side bypass pipe 27. Flows, and the secondary coolant exchanges heat with air in the heat transfer tube 23a of the air cooler 23, whereby heat generated in the core is finally exhausted.
[0040]
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 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.²A cover having a pressure of is sealed, so that when the coolant is drained, the gas pushed out from the drain tank side can be transferred to the secondary cooling system side.
[0041]
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 guided from the overflow column 19 and the steam generator 5 have on-off valves, respectively. These overflow pipes 21 and 22 are also integrated with each other and connected to the first drain tank 9. I have.
[0042]
In the present embodiment, the drain pipes 11, 12, and 13 are respectively provided with automatic opening / closing valves 14 to 18 that are opened in an emergency. That is, the drain pipes 11 and 13 which are integrated with each other are provided with automatic opening / closing valves 14 and 16 at the drooping portions between the pipes 2 and 8 to which they are connected and the integration section (point A), respectively. An automatic opening / closing valve 17 is provided at an intermediate portion from the portion (point A) to the drain tank 9. These automatic opening / closing valves 14, 16, 17 are each configured as a set of two parallel automatic opening / closing valves (valve elements) 14a, 14b, 16a, 16b, 17a, 17b. Thus, two sets of automatic on-off valves 14, 16, and 17 each having two parallel units are arranged in series in each of the drain pipes 11, 13 in front of and behind the integrated portion (point A).
[0043]
In addition, another drain pipe 12 connected to the upstream pipe 6 for returning the secondary coolant also has an upstream automatic opening and closing part in a hanging part between each pipe 6 to which it is connected and the drain tank 10. A valve 15 and a downstream automatic opening / closing valve 18 are provided. These automatic opening / closing valves 15 and 18 are also configured as one set each of two parallel automatic opening / closing valves (valve elements) 15a, 15b, 18a and 18b. Two sets of valves 15 and 18 are arranged in series.
[0044]
As shown in FIG. 33, a liner plate 37 is provided on the inner surface of the floor of the building where the devices and pipes are installed so as to store or transfer the leaking coolant such as sodium.
[0045]
According to such a configuration, by opening the automatic opening / closing valves 14 to 18 of the drain pipes 11, 12, 13 in an emergency, the secondary coolant in the secondary cooling system can be reliably stored in the drain tanks 9, 10. Can be discharged. In other words, since the secondary cooling system equipment and piping are generally installed in an air atmosphere, if sodium or the like as the secondary cooling material leaks to the outside, it reacts chemically with oxygen in the atmosphere. 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.
[0046]
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. Of these pipes, the drain pipe 11 has two parallel automatic opening / closing valves 14a and 14b. , 17a, 17b are connected in series, the drain pipe 13 is connected with two parallel automatic opening / closing valves 16a, 16b, 17a, 17b, and the drain pipe 12 is connected with two parallel automatic opening / closing valves 15a, 15b, 18a. , 18b are installed in series, so that even if any one of the sets of the automatic opening and closing valves 14a to 18b does not open, the other valve can be opened. The pipes 11 to 13 are reliably conducted 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.
[0047]
Therefore, according to the present embodiment, when an emergency such as leakage of the coolant occurs, the coolant can be drained reliably and promptly, whereby the amount of corrosion thinning of the liner plate is suppressed or the leakage is continued. It is possible to prevent the effect of the fire from spreading.
[0048]
In the present embodiment, since the coolant supply pipe 2 is longer than the downstream return pipe 8, the coolant is simultaneously discharged through the drain pipes 11 and 13 of both the pipes 2 and 8. Is performed, the drain pipe 13 of the return pipe 8 which is relatively short ends draining early, but the integrated part (point A) of both drain pipes 11 and 13 and the pipe 2 and the drain pipe 11 are connected. The height difference Ho (m) from the branch point (point B) is the pressure loss between the points A and B in the pressure loss occurring in the drain pipe 11 when it is assumed that the drain pipe 11 is drained alone. When the pressure loss (water head equivalent) with respect to the entire length is ΔPo (m), the position satisfies Ho> ΔPo.
[0049]
Thereby, for example, even when the coolant discharge from the pipe 8 portion is terminated first via the drain pipe 13 and the remaining coolant is discharged from the pipe 2 portion via the other drain pipe 11, 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.
[0050]
In the above-described first embodiment, a case has been described in which two sets of automatic on-off valves having a two-parallel configuration are arranged in series with respect to each drain pipe. Any number of the above may be used. 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).
[0051]
Second embodiment (FIG. 2)
FIG. 2 is a system diagram showing a second embodiment of the present invention.
[0052]
As in the first embodiment described above, this embodiment is also for a secondary cooling system in a drain facility of a fast reactor, and has a drain pipe provided with an automatic opening / closing valve that opens in an emergency. The first embodiment is different from the first embodiment in that a plurality of valves are arranged in series as one set, and a plurality of automatic on-off valves are arranged in a drain pipe in parallel.
[0053]
That is, as specifically shown in FIG. 2, in this embodiment, the drain pipes 11, 12, and 13 configured in the same manner as in the first embodiment are provided with automatic opening / closing valves 14 to 18 that are respectively opened in an emergency. As for the drain pipes 11 and 13 which are integrated with each other, the automatic open / close valves are respectively provided at the drooping portions between the pipes 2 and 8 to which they are connected and the integrated portion (point A) as in the first embodiment. 14 and 16 are 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 opening / closing valves 14 and 16 are each configured as one set by two automatic opening / closing valves (valve elements) 14a, 14b, 16a and 16b in parallel. Thus, two sets of automatic on-off valves 14, 16, and 17 each having two parallel units are arranged in series in each of the drain pipes 11, 13 in front of and behind the integrated portion (point A).
[0054]
On the other hand, as for another drain pipe 12 connected to the pipe 6 on the upstream side for returning the secondary coolant, an automatic opening / closing valve is provided in a drooping portion between each pipe 6 to which it is connected and the drain tank 10. Although 15, 18 are provided, the configuration of these automatic on-off valves 15, 18 is different from that of the first embodiment. That is, although the drain pipe 12 has a configuration of a single pipe 12a halfway, it is divided into two branch pipe sections 12b and 12c halfway, and one of the branch pipe sections 12b has an in-line two-way automatic opening / closing valve. (Valve elements) 15a, 15b are provided, and the other branch pipe section 12c is also provided with two automatic on-off valves (valve elements) 18a, 18b in series, whereby the two automatic on-off valves 15, 18 are connected in series. Depending on the configuration, two sets are arranged in parallel.
[0055]
The other configuration is the same as that of the first embodiment, and the description is omitted.
[0056]
According to the second embodiment having such a configuration, the drain pipes 11 and 13 perform the same operation as the first embodiment. Further, as for the drain pipe 12, since two automatic on-off valves 15a, 15b, 18a and 18b are installed in parallel, one of the automatic on-off valves 15 and 18 may not be opened. Even so, the coolant can be discharged by opening the other valve.
[0057]
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 promptly, thereby suppressing the amount of corrosion thinning of the liner plate or maintaining the leakage. The effect of the fire can be prevented from spreading.
[0058]
In this embodiment, the case where two sets of automatic on-off valves in parallel or in series are arranged in series or in parallel for each drain pipe has been described. Any number of the above may be used.
[0059]
Third embodiment (FIG. 3)
FIG. 3 is a system diagram showing a third embodiment of the present invention.
[0060]
Although the basic configuration of this embodiment is the same as that of the first embodiment, 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, and another drain pipe 12d is not provided. , 12e are connected to different drain tanks 10a, 10b, respectively, and the non-integrated drain pipes 12d, 12e are connected to each other by a conductive pipe (tie line) 12f at a position downstream of the automatic on-off valve. Is provided with another automatic opening / closing valve 18c. Other configurations are the same as those in the first embodiment, and therefore, the same reference numerals as in FIG. 1 are used in FIG. 3 and the description is omitted.
[0061]
According to the present embodiment having such a configuration, even if any one of the automatic on-off valves 18a, 18b, and 18c provided in a portion of the drain pipe 12 close to the tank is not opened, the pipe of the drain pipe 12 is not opened. The road is reliably connected to the two drain tanks 10a and 10b, and the effect that drain is 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 12d from the integration point of the tie line 12f to the drain tanks 10a and 10b can be obtained. , 12e is long, the flow rate of the drain to each of the drain tanks 10a, 10b can be distributed to about ず つ each, so that the pressure loss in the relevant portion can be reduced, thereby cooling even when the automatic on-off valve fails. It is possible to prevent the material discharge time from being delayed.
[0062]
Fourth embodiment (FIG. 4)
FIG. 4 is a system diagram showing a fourth embodiment of the present invention.
[0063]
Although the basic configuration of this embodiment is the same as that of the first embodiment, 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, and the other is not. Is different in that the drain pipe 13 is integrated with the overflow pipes 21 and 22 and connected to the drain tank 9. One of the independent drain pipes 11 is provided with two sets of automatic open / close valves 14 (14a, 14b) and 17 (17a, 17b) in series, and two drain valves 13 are provided in series. Two sets of automatic on-off valves 16 (16a, 16b) and 41 (41a, 41b) in a two-parallel configuration are provided in series upstream of an integrated portion (point C) with the overflow pipes 21 and 22.
[0064]
The height difference H1 (m) between the integrated portion (point C) of the drain pipe 13 and the overflow pipes 21 and 22 and the branch point (point D) of the pipe 8 and the drain pipe 13 is independent of the drain pipe 13 When the pressure loss from the point C to the point D is ΔP1 (m) in the pressure loss (water head equivalent) of the drain pipe 13 when it is assumed that the drain is performed, the position satisfying H1> ΔP1 Has become.
[0065]
Other configurations are the same as those of the first embodiment, and therefore, the same reference numerals as in FIG.
[0066]
According to the fourth embodiment having such a configuration, similarly to the first embodiment, one of the automatic open / close valves 14a, 14b, 17a, 17b, 16a, 16b, 41a, and 41b in the parallel configuration is opened. Even if this is not the case, the conduits 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. In addition, by setting the automatic opening / closing valves 14a, 14b, 17a, 17b, 16a, 16b, 41a, 41b installed in parallel to have the same capacity, even if any of the automatic opening / closing valves cannot be opened, a predetermined time is required. Of the coolant can be discharged.
[0067]
Further, since the drain pipe 13 is integrated with the overflow pipes 21 and 22 without being integrated with the drain pipe 11, these overflow pipes 21 and 22 can also be used as drain pipes, and the number of drain pipes to be installed can be reduced. It becomes possible. 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, the overflow also occurs in the event of an emergency drain at the time of coolant leakage. 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.
[0068]
Furthermore, a 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 from the drain pipe 13 H1> ΔP1 is satisfied when ΔP1 (m) is the pressure loss from point C to point D in the pressure loss (water head equivalent) of the drain pipe 13 when it is assumed that the coolant is discharged alone. Therefore, when the coolant is discharged from the drain pipe 13 to the pipe 8, there is no possibility that the gas flows from the overflow pipes 21 and 22 and the drain flow rate is reduced.
[0069]
Fifth embodiment (FIG. 5)
FIG. 5 is a system diagram showing a fifth embodiment of the present invention.
[0070]
This embodiment has a drain pipe configuration substantially similar to that of the fourth embodiment, except that drain pipes 13 and 42 are connected to two positions of the coolant return pipe 6 at positions before and after the circulation pump 7. The difference is that the drain pipes 13 and 42 are integrated (point E) and then integrated with the overflow pipes 21 and 22 (point F). Each of these drain pipes 13 and 42 has two parallel automatic opening / closing valves 16 (16a, 16b) and 43 (43a, 43b) upstream of an integrated portion (point F) with the overflow pipes 21 and 22. ) Are provided, and an automatic on-off valve 41 (41a, 41b) having two parallel arrangements is provided downstream of the integration unit. Other configurations are the same as those of the fourth embodiment, and therefore, the same reference numerals as in FIG.
[0071]
According to the fifth embodiment having such a configuration, the drain pipe 42 is branched on the upstream side of the circulation pump 7 of the pipe 8, so that the discharge around the steam generator 5 where the volume of the coolant becomes large even in the secondary cooling system. The effect that can be performed early is added.
[0072]
The installation height of the integrated part (point E) of the drain pipe 13 and the drain pipe 42 and the installation height of the integrated part (point F) of the overflow pipes 21 and 22 after the integration of the drain pipes 13 and 42 are set. Is the same as in the fourth embodiment.
[0073]
Sixth embodiment (FIG. 6)
FIG. 6 is a system diagram showing a sixth embodiment of the present invention.
[0074]
This embodiment has a drain pipe configuration similar to that of the fourth embodiment. However, a gas discharge pipe 44 for opening to the atmosphere is branched from the cover gas pipe 30 and two gas discharge pipes 44 are connected in parallel. The automatic opening / closing valves 45a and 45b for controlling the released gas are installed. Other configurations are the same as those of the fourth embodiment, and therefore, the same reference numerals as in FIG.
[0075]
According to the sixth embodiment having such a configuration, it is possible to reduce the gas flow rate in the cover gas pipe 30 when the coolant is discharged, and to reduce the pressure loss due to the gas flow in the cover gas pipe 30.
[0076]
That is, the coolant is discharged to the drain tank 9 from the drain pipe 11 connected to the pipe 2 for supplying the coolant and the drain pipe 13 connected to the downstream pipe 8 for returning the coolant, and the coolant is returned. When the coolant is discharged from the drain pipe 12 connected to the upstream piping 6 to another drain tank 10, a gas having the same volume as the coolant is pushed out from each of the drain tanks 9 and 10, and the secondary cooling is performed. Move to the system side.
[0077]
At this time, if the cover gas flow rate from the drain tank 9 is V1 and the cover gas flow rate from the drain tank 10 is V2, when the cover gas is not discharged, the flow rate V3 of the cover gas pipe 30 becomes:
(Equation 1)
V3 = V1 + V2
It becomes.
[0078]
On the other hand, in the present 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 becomes:
(Equation 2)
V3 = V1 + V2-V4
Thus, 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.
[0079]
In addition, since the entire system including the secondary cooling system and the drain tanks 9 and 10 is depressurized, the pressure difference between the system and the atmosphere is eliminated, leading to a reduction in the leak rate until the drain is completed.
[0080]
Seventh embodiment (FIGS. 7 to 11)
This embodiment relates to a coolant drain of a nuclear reactor having a liquid level gauge for measuring a coolant level in a drain tank, and FIG. 7 is a system diagram showing an entire configuration of the drain equipment. . FIG. 8 is a partially enlarged view showing a configuration for mounting the liquid level gauge on the drain tank, and FIG. 9 is an enlarged view showing a portion G in FIG. 10 and 11 show modified examples, which correspond to FIGS. 8 and 9, respectively.
[0081]
In this embodiment, the case where the mounting structure of the liquid level gauge is applied to the drain equipment system shown in the first embodiment is exemplified, and the entire structure of the system is denoted by the same reference numeral in FIG. 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.
[0082]
As shown in FIG. 7, vertically long bar-shaped liquid level gauges 50 and 51 are inserted into the drain tanks 9 and 10, respectively, and the upper ends of the liquid level gauges 50 and 51 are attached to the drain tanks 9 and 10 in the same manner. Fixed by configuration. In the following description, the mounting configuration of the liquid level gauge 50 to one drain tank 9 will be described.
[0083]
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 that rises integrally. A nozzle flange 53 is formed at an upper end of the nozzle 52. I have. 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 the vertically long rod-shaped body, and is configured to obtain an electric output corresponding to the liquid level 60 outside the liquid level gauge sheath 55. A flange 57 is provided on the upper end side of the projection 50. The level gauge sheath 55 has a vertically long cylindrical shape with an upper end opening and a lower end closed, and covers the periphery of the level gauge 50 with a certain gap therebetween. A large-diameter flange-shaped lid 54 mounted on the nozzle flange 53 to close the nozzle 52 and a flange 57 of the liquid level gauge 50 protruding from a position at a constant height L above the lid 54 can be abutted and supported. The level gauge and the flange 56 are provided integrally. 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 by bolts or the like in a sealed state. The lower ends of the level gauge 50 and the level gauge sheath 55 are inserted near the inner bottom of the drain tank 9.
[0084]
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. An O-ring having good properties is provided as a sealing material. The joining surface between the level gauge sheath 56 and the flange 57 of the level gauge 50 is a boundary 59 between the internal space of the level gauge sheath 55 and the external atmosphere, and this boundary 59 is directly connected to the drain tank 9. Since there is no communication with the inside, there is no requirement for airtightness during normal use, but in the unlikely event that the level gauge sheath 55 is damaged, the coolant enters the gap between the level gauge 50 and the level gauge sheath 55. Even if it rises, the liquid level of the liquid level gauge 55 and the liquid level gauge 50 are adjusted so as to obtain sufficient airtightness to secure sufficient time for the gas inside the liquid level gauge 55 to completely escape. Both contact surfaces with the flange 57 are surface-finished.
[0085]
FIG. 9 further illustrates the above-mentioned joints in order to explain details of the width d of the gap between the level gauge 50 and the level gauge sheath 55, the thickness t of the peripheral wall of the level gauge sheath 55, and the like. It is shown enlarged. As shown in FIG. 9, even if the level gauge sheath 55 is broken and the above-mentioned coolant enters the gap between the level gauge 50 and the liquid level gauge 50, the connection with the level gauge 50 may occur. Before flowing out from a certain boundary 59 to the outside, the liquid level gauge which is a connection part with the liquid level gauge 50 from the lid 54 which is an attachment part to the drain tank 9 so that the temperature of the coolant drops to the solidification point and solidifies. In the protruding portion up to the flange 56, a sheath thickness t and a protruding length L corresponding to the gap width d with the liquid level gauge 50 are secured so that the temperature of the sheath portion is sufficiently lower than, for example, the sodium freezing point (about 98 ° C.). I have.
[0086]
In this way, even if the level gauge sheath 55 is damaged, coolant such as sodium, which has risen in the gap between the level gauge sheath 55 and the level gauge 50, can be removed from the nozzle lid 54 and the level gauge sheath. It freezes between the flange 56 and does not reach the boundary 59 which is the connection portion with the liquid level gauge 50, and is prevented from flowing out from the boundary 59.
[0087]
That is, according to the present embodiment, a gap is formed between the periphery of the level gauge 50 and the level gauge sheath 55, and the level gauge 50 and the level gauge sheath 55 project upward from the drain tank 9. A seal portion is provided at the position, and the gap is formed so that the coolant that enters the gap due to breakage of the liquid level gauge 55 and rises can be cooled to the freezing point and solidified before flowing out of the seal portion to the outside. Since the protrusion length is set, it is possible to prevent the base coolant from flowing out from the seal portion, thereby providing an effect of ensuring safety.
[0088]
Next, a modified example of the mounting structure of the liquid level gauge 50 will be described with reference to FIGS. FIG. 10 is an enlarged view corresponding to FIG. 8 described above, and FIG. 11 is an enlarged view of a portion H in FIG.
[0089]
As shown in these figures, in this modified example, the liquid level gauge sheath 55 is attached to the drain tank 9 from the nozzle lid 54 to the liquid level gauge sheath flange 52 which is a connection part with the level gauge 50. The fin structure 63 is provided on the protruding portion of the fin.
[0090]
As a result, as compared with the case where the fin structure 63 is not provided, the heat radiation ability of the protruding portion is further improved, and even if the level gauge sheath 55 is damaged and the coolant vapor enters the gap, The temperature can be more quickly lowered to the freezing point and frozen. For this reason, the prevention of coolant leakage to the outside becomes more reliable.
[0091]
As shown in FIG. 11, in this modified example, an O-ring 64 is provided as a sealing material on the connection surface between the level gauge or the flange portion 56 and the flange 57 of the level gauge 50.
[0092]
Thereby, the sealing performance of the boundary 59 between the internal space of the liquid level gauge 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 in 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, the prevention of coolant leakage to the outside becomes more reliable.
[0093]
In the above description, the O-ring 64 is shown as an example of the sealing material. However, if the sealing property can be maintained, the same effect can be obtained even with a sheet-shaped packing gasket.
[0094]
Further, 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, but the same effect can be obtained when a PT screw structure is adopted. As a means for improving the sealing performance in this case, by inserting a sealing tape, the same effect as when an O-ring or a sheet-shaped packing gasket is installed in the flange structure can be obtained.
[0095]
Eighth embodiment (FIG. 12)
The present embodiment relates to a configuration in which a thermometer is installed in a drain tank in order to measure the temperature of a coolant that may flow into the drain tank, and FIG. 12 is a system configuration diagram thereof. In this embodiment, a case where the mounting configuration of the thermometer is applied to the drain equipment system shown in the first embodiment is also illustrated, and the overall 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.
[0096]
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.
[0097]
The mounting configuration of these thermometers 61 and 62 to the drain tanks 9 and 10 is substantially the same as the mounting configuration of the liquid level gauges 50 and 51 of FIGS. 8 to 11 showing the seventh embodiment. That is, the liquid level gauges 50 and 51 described above are replaced with thermometers 61 and 62, and the liquid level gauge sheath 55 described above is replaced with a thermometer sheath.
[0098]
Also in this embodiment, as in the case of the level gauge sheath, the sheath size corresponding to the gap width with the thermometer is set so that the temperature of the protruding portion of the thermometer sheath is sufficiently lower than the sodium freezing point (about 98 ° C.). It is configured to ensure thickness and protruding length.
[0099]
With this configuration, even if the thermometer sheath is damaged, the sodium that has entered the sheath will freeze at that portion and reach the connection between the thermometer body and the thermometer sheath. Is prevented from flowing out.
[0100]
In addition, as the mounting configuration of the thermometers 61 and 62 in the present embodiment, all the configurations including the modifications in the seventh embodiment can be applied, and the same effects can be obtained.
[0101]
Ninth embodiment (FIGS. 13 and 14)
The present embodiment relates to a configuration in which a drive unit 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.
[0102]
As shown in these figures, in the present embodiment, the drive unit 102b of the automatic on-off valve 102a is covered and protected by a heat-resistant protective box 101a. The heat-resistant protective box 101a is, for example, a rectangular parallelepiped, and includes a top plate 103, a bottom plate 104, and respective side plates 105, and edges of these plates 103, 104, and 105 are joined by an attachment jig 106 so as to be disassembled. Assembled.
[0103]
Each of the top plate 103, the bottom plate 104, and the side plate 105 are respectively provided with an outermost plate 107, an inner plate 108 with a space therebetween, and a heat insulating material 109 filled therebetween. And is constituted by.
[0104]
According to the present embodiment having such a configuration, even if the coolant such as sodium leaks to the outside and the ambient temperature becomes high due to a chemical reaction with oxygen in the ambient, it is assumed that the automatic opening / closing operation is performed. Since the drive section 102b of the 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.
[0105]
In addition, since the heat-resistant protection box 101a is configured to be disassembled, it is possible to work efficiently by disassembling and assembling when inspecting the drive unit 102b of the automatic on-off valve 102a and the heat-resistant protection box 101a. Efficiency can be improved, and it can be easily applied to an existing automatic on-off valve.
[0106]
Tenth embodiment (FIGS. 15 and 16)
This embodiment also relates to a configuration in which the drive unit 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.
[0107]
As shown in these figures, the heat-resistant protective box 101b of the present 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 unit 102b of the automatic opening / closing valve 102a is covered and protected by the heat-resistant protection box 101a. The heat-resistant protection box 101a is formed as a cylindrical body, for example, a disk-shaped top plate 103 and A bottom plate 104 and a split tubular side plate 105 joined to the periphery thereof are provided, and the edges of these plates 103, 104, 105 are assembled by being disassembled by a mounting jig 106.
[0108]
As in the ninth embodiment, the top plate 103, the bottom plate 104, and the side plate 105 are each provided with an outermost plate 107 disposed at the outermost position, an inner plate 108 disposed at an interval therebetween, and an inner plate 108 disposed therebetween. And a heat insulating material 109 filled in.
[0109]
According to the present embodiment, in addition to the same effects as in the ninth embodiment, by making the shape of the heat-resistant protective box 101b a cylinder, the strength against the rise in the atmospheric pressure in the installation room when the coolant (sodium or the like) leaks to the outside is obtained. And the distance from the outside of the heat-resistant protective box 101b to the drive unit 102b is substantially the same in each direction due to the shape thereof, so that an effect of suppressing a temperature difference between the respective units of the drive unit 102b is achieved.
[0110]
Eleventh embodiment (FIGS. 17 to 19)
The present embodiment relates to a configuration in which an opening window is provided in the heat-resistant protective box in the ninth and tenth embodiments, and a closing lid having heat insulation and elasticity is attached to the opening window.
[0111]
FIG. 17 is a perspective view showing a case where this embodiment is applied to the heat-resistant protective box 101a of the ninth embodiment (FIGS. 13 and 14), and FIG. 18 is a tenth embodiment (FIGS. 15 and 16). It is a perspective view showing the case where this embodiment is applied to the heat resistant protection box 101a of FIG.
[0112]
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 the opening window 111 has a heat insulating and extensible, for example, bellows-like closing lid 112. The closing lid 112 is provided to be openable and closable along the guide groove 114. The closing lid 112 always contracts to open the opening window 111, and extends along the guide groove 114 in an emergency to close the opening window 111 confidentially.
[0113]
FIGS. 19A, 19B, and 19C are enlarged views showing different configuration examples (112a, 112b, 112c) of the closing lid 112, respectively.
[0114]
The closing lid 112a 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, and the bellows contracts. It has a shaped 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 into the heat-resistant protective boxes 101a and 101b. Acts to suppress the invasion of heat.
[0115]
The closing lid 112b of FIG. 19B has a three-layer structure as a whole, and includes lid bodies 15a and 15b having a two-layer structure in which dissimilar metals A and B are joined, and a heat insulating material 113. 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 larger coefficient of thermal expansion than the lid body 115b of the metal B facing the inside, and under a normal atmosphere temperature environment. Has a contracted bellows shape. Then, when the ambient temperature becomes high, it extends along with the heat insulating material 113 along the groove 114, closes the opening window 111, and has a function of suppressing heat from entering the heat-resistant protective boxes 101a and 101b. Do.
[0116]
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 bonded to the inner surface of the heat-resistant protective box, and shrinks under a normal atmosphere temperature environment. When the ambient temperature is high, the gas in the cover body 116 made of bellows expands along with the heat insulating material 113 along the groove 114 by the thermal expansion of the gas, and the opening window 111 is opened. It acts to close and prevent heat from entering the heat-resistant protective box.
[0117]
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 is automatically closed by the temperature change. , 112b, 112c), and has an effect of suppressing heat from entering the heat-resistant protective box 101 (101a, 101b). Further, since the heat-resistant protective box 101 (101a, 101b) is in an open state during normal operation, heat received by heat conduction from the automatic on-off valve can be released to the outside of the heat-resistant protective box. Effects such as a simple inspection of the drive unit can be achieved without disassembling the protection box.
[0118]
Twelfth embodiment (FIG. 20)
This embodiment also has an opening window provided in the heat-resistant protective box in the ninth and tenth embodiments, but differs from the eleventh embodiment in that a heat-insulating closing lid attached to the opening window detects high heat. It is of a normally open type fixed by a fixing jig that closes by the above. FIG. 20 is a perspective view showing the heat-resistant protective box of the present embodiment.
[0119]
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 thermal effect when the temperature exceeds a predetermined temperature, and is in a connected state under a normal ambient temperature environment. When the temperature becomes high, the opening window 111 is closed because it is broken and the closing lid 112 is opened.
[0121]
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, so that the closing lid 112 closes the opening window 111, and the heat resistance is reduced. In addition to suppressing the intrusion of heat into the protection box 101, the heat received from the heat conduction from the automatic opening / closing valve can be released to the outside of the heat protection box by the normally open state during normal operation, and the heat protection box 101 is disassembled. There is an effect that a simple inspection of the drive unit can be performed without doing so.
[0122]
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, and the net is coated with a foaming paint having heat insulation performance. is there.
[0123]
FIG. 21 is a perspective view showing a case where this embodiment is applied to the heat-resistant protective box 101a of the ninth embodiment (FIGS. 13 and 14), and FIG. 22 is a tenth embodiment (FIGS. 15 and 16). It is a perspective view showing the case where this embodiment is applied to the heat resistant protection box 101a of FIG. FIG. 23 is an enlarged view showing the configuration of the wire net 117. As shown in FIG.
[0124]
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 a wire mesh 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.
[0125]
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 or heat protection The entire box is 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 to the outside of the heat-resistant protective box. Effects such as a simple inspection of the drive unit can be obtained without disassembly.
[0126]
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 insulation.
[0127]
FIG. 24 is a perspective view showing a case where this embodiment is applied to the heat-resistant protective box 101a of the ninth embodiment (FIGS. 13 and 14), and FIG. 25 is a tenth embodiment (FIGS. 15 and 16). It is a perspective view showing the case where this embodiment is applied to the heat resistant protection box 101a of FIG.
[0128]
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 a foam paint 118 is applied to the surface of the wire mesh 117 as in the thirteenth embodiment. Have been. 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.
[0129]
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 are closed from the outside. Thus, heat is prevented from entering the heat-resistant protective boxes 101a and 101b. 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, and further, a simple inspection of the drive unit can be performed without disassembling the heat-resistant protection boxes 101a and 101b. Effects such as being possible are achieved.
[0130]
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 the support structure.
[0131]
As shown in FIG. 26, in the present embodiment, a support device 119 is provided in the building 33, and the drive unit 102 b of the automatic on-off valve 102 a is connected to the support device 119 via a support pipe 122. The heat-resistant protective box 101 that covers the drive unit 102b of the automatic opening / closing valve 102a 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 a support device 119. The support pipe 122 is inserted into a through hole 122 formed in the heat-resistant protection box 101.
[0132]
According to the present embodiment configured as described above, by supporting the load of the heat-resistant protection box 101 with the support device 119, the load of the heat-resistant protection box 101 is not applied to the automatic on-off valve 102a, and an extra load is applied. The occurrence of a valve failure due to the load can be suppressed, thereby improving the reliability of the operation function of the automatic on-off valve 102a. 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 penetrating the heat-resistant protective box 101 can be minimized, and the effect of suppressing the intrusion of heat from the penetrating portion is exerted.
[0133]
Sixteenth embodiment (FIGS. 27 to 29)
This embodiment relates to a support structure for a heat-resistant protective box.
[0134]
FIG. 27 is a perspective view showing a case where this embodiment is applied to the heat-resistant protective box 101a of the ninth embodiment (FIGS. 13 and 14), and FIG. 28 is a tenth embodiment (FIGS. 15 and 16). It is a perspective view showing the case where this embodiment is applied to the heat resistant protection box 101a of FIG. FIG. 29 is a side view including the automatic on-off valve 102a.
[0135]
As shown in FIGS. 27 and 28, in this embodiment, the heat-resistant protective boxes 101 a and 101 b are attached to the frame 123, whereby 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 on-off 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 periphery of the penetrating part. It is covered by a heat-resistant skirt 128.
[0136]
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 can be suppressed. Thus, the reliability of the operation function of the automatic on-off valve 102a is improved. Further, the penetration of the automatic opening / closing valve 102a into the heat-resistant protection boxes 101a and 101b is covered with the heat-resistant skirt 128 in which a heat insulating material is laid, so that the effect of suppressing the intrusion of heat from the penetrations is exerted. .
[0137]
Seventeenth embodiment (FIG. 30)
In the present embodiment, a heat insulating material or the like is 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.
[0138]
As shown in FIG. 30, in the present embodiment, the heat-resistant protection box 101 is connected to the support device 119 of the automatic on-off valve 102a, and the inside of the hollow support pipe 120 penetrating the heat-resistant protection box 101 is insulated. A member 123 is provided, and the 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.
[0139]
According to the present embodiment, by providing the heat insulating material 123 inside the support pipe 120 penetrating the heat-resistant protective box 101, it becomes possible to suppress the convective heat transfer in the hollow support pipe 120. By reinforcing the periphery of the through hole 122 with the heat insulating material 125, the effect of suppressing heat input into the heat-resistant protective box 101 is achieved.
[0140]
Eighteenth embodiment (FIG. 31)
In the present embodiment, in addition to the configuration shown in the seventeenth embodiment (FIG. 30), a heat insulating material is further added to the drive unit of the automatic on-off valve and the like. FIG. 31 is a sectional view showing the structure.
[0141]
In the present embodiment, as shown in FIG. 31, in addition to the configuration in FIG. 30, the drive unit 102 b of the automatic on-off valve 102 a covered with the heat insulation 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.
[0142]
According to this embodiment having such a configuration, by covering the drive unit 102b with the heat insulating material 126, the heat resistance of the automatic on-off valve 102a can be improved, and the surface of the protection unit 102c can be whitened or polished. Since 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 to the outside, the effect of slowing down the temperature increase in the protection portion 102c is exerted.
[0143]
Nineteenth embodiment (FIG. 32)
This embodiment relates to a cable for driving an automatic on-off valve, and FIGS. 32A and 32B are configuration diagrams showing different cables according to the present embodiment.
[0144]
In the first example shown in FIG. 32A, a 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 130.
[0145]
In the second example shown in FIG. 32B, the outside of a similar heat-resistant cable 129 is covered with a conduit (electric conduit) 131.
[0146]
According to the present 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. The cable 129 is reliably protected, and the function of the cable is not impaired, so that the function of the automatic on-off valve 102a is maintained.
[0147]
【The invention's effect】
As described above in detail, according to the present invention, in the cooling system of a nuclear reactor, even when leakage of the coolant occurs, the coolant can be reliably discharged to the drain tank, and the drain pipe and the cover gas Effective control of flow resistance in pipes and reduction of drain flow rate due to entrainment of gas, terminates drainage early, and appropriately protects the valve drive unit against an increase in ambient temperature due to a chemical reaction of coolant. be able to. Therefore, by improving the reliability of the drain function and terminating the drain quickly and reliably, there is an effect that the corrosion thinning of the liner plate can be greatly reduced.
[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 the liquid level gauge to the drain tank in FIG. 7;
FIG. 9 is an enlarged view showing a portion G extracted from FIG. 8;
FIG. 10 shows a modification of the seventh embodiment, and is a view corresponding to FIG.
FIG. 11 is an enlarged view showing an extracted portion H of 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. 19A, 19B, and 19C are enlarged views each showing a specific configuration example of the eleventh embodiment; FIGS.
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. 32A and 32B are configuration diagrams 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]
1 intermediate heat exchanger
2 Piping
3 header
4-minute piping
5 Steam generator
6 Piping
7 Circulation pump
8 Piping
9,10 Drain tank
10a, 10b Drain tank
11,12,13 Drain pipe
12d, 12e drain pipe
12f Conductive tube (Tie line)
14,15,16,17,18 Automatic open / close valve
14a, 14b, 15a, 15b, 16a, 16b, 17a, 17b, 18a, 18b, 18c, 41a, 41b, 43a, 43b, 45a, 45b Automatic open / close valve (valve element)
19 Overflow column
20 overflow pipe
21,22 overflow pipe
23 Air cooler
23a heat transfer tube
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 piping
31 sodium equipment
32 sodium piping
32 piping
33 Building
34 sleeve
35 floor
36 Insulation
37 Liner
38 lid
42 drain pipe
44 Gas release piping
50,51 Level gauge
52 nozzles
53 Nozzle flange
54 lid
55 Level gauge sheath
56 Level gauge sheath flange
57 Tsuba
58,59 border
60 liquid 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 plate
104 bottom plate
105 side plate
106 Mounting jig
107 Exterior plate
108 Interior board
109 Insulation
110 One side
111 window
112, 112a, 112b, 112c Closing lid
114 Guide groove
115a, 115b, 116 Lid body
117 Wire Mesh
118 Foam paint
119 Support device
120 Support pipe
121 Mounting jig
122 Support pipe
123 Insulation
124 exterior plate
125 Insulation
126 Insulation
127 Fixing jig
128 heat resistant skirt
129 heat resistant cable
130 Insulation
131 Conduit

Claims (15)

A coolant drain facility that is provided in a coolant circulation system of a nuclear reactor using liquid metal as a coolant and discharges the coolant to a drain tank through a drain tube from equipment or piping of the system. The automatic on-off valve which is sometimes opened is provided, and the automatic on-off valve is configured as a set of a plurality of parallel on-off valves, and a plurality of the automatic on-off valves are arranged in the drain pipe in series. Refrigerant coolant drain equipment. A coolant drain facility that is provided in a coolant circulation system of a nuclear reactor using liquid metal as a coolant and discharges the coolant to a drain tank through a drain tube from equipment or piping of the system. An automatic on-off valve which is sometimes opened is provided, wherein the automatic on-off valve is configured as a set of a plurality of in-line automatic on-off valves, and a plurality of the automatic on-off valves are arranged in the drain pipe in parallel. Refrigerant coolant drain equipment. 3. The coolant drain system for a nuclear reactor according to claim 1, wherein the drain pipes are integrated at an outlet position of an automatic opening / closing valve disposed close to the drain tank and connected to one drain tank, or each of the drain pipes is integrated without being integrated. A coolant drain facility for a nuclear reactor, wherein the coolant drain facility is connected to a drain tank. 4. The coolant drain equipment 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, and the drain pipes are not integrated. A coolant drain facility for a nuclear reactor, wherein drain pipes are connected to each other at a position downstream of the automatic open / close valve by a conductive pipe, and another automatic open / close valve is provided in the conductive pipe. 5. The coolant drain facility for a nuclear reactor according to claim 1, wherein two drain pipes hanging down from drain nozzles of equipment or pipes having different coolant distribution systems are integrated by a pipe integration unit to form a drain tank. The drainage of one of the two drain pipes, from which the coolant discharge ends earlier, is determined by the height difference from the drain nozzle to the pipe integration part. Wherein the pressure loss (equivalent to the water head) during continuous discharge of the coolant from the drain nozzle to the pipe integration portion is set to be greater than the pressure loss. 5. 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 integrated by a pipe integration unit to drain. Connected to a tank, the drainage of one or more of these drain pipes from which the coolant discharge ends first is determined by the height difference from the drain nozzle to the pipe integration part. Wherein the pressure loss (equivalent to the water head) during continuous discharge of the coolant from the drain nozzle to the pipe integration portion is set to be greater than the pressure loss. 7. The coolant drain facility for a nuclear reactor according to claim 1, wherein the pipe to which the drain pipe is connected is an overflow for constantly causing excess coolant in a system through which the coolant flows to overflow to the drain tank. 8. Coolant drain equipment for a nuclear reactor, characterized by being system piping. The coolant drain facility for a nuclear reactor according to any one of claims 1 to 7, wherein a device, a pipe, or a drain tank of a coolant distribution system includes an emergency discharge of the coolant to the drain tank, and the device, the pipe, or A coolant drain facility for a nuclear reactor, comprising a pipe for releasing cover gas from a drain tank and an automatic on-off valve. 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 a coolant stored in the drain tank. The gauge is covered with a level gauge sheath, inserted through a nozzle section provided on an upper wall of the drain tank through the level gauge sheath, and is provided around the level gauge with the level gauge sheath. In addition to forming a gap between these, the level gauge and the level gauge sheath have a seal portion at a position protruding above the drain tank, and the gap is caused by any damage of the level gauge sheath. A coolant drain facility for a nuclear reactor, characterized in that the coolant drain facility is configured to have an upward protruding length that allows the temperature of the coolant that intrudes into the gap and rises to the freezing point before the coolant flows out of the seal portion and solidifies. 10. The coolant drain facility 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, wherein the thermometer is a thermometer. Along with covering with the sheath, the thermometer sheath is inserted and installed in a nozzle portion provided on the upper wall of the drain tank, and a gap is formed between the thermometer sheath and the thermometer around the thermometer, These thermometer and thermometer sheath have a seal portion at a position protruding above the drain tank, and the gap is provided with a coolant that enters the gap due to breakage of the liquid level gauge sheath and rises. A coolant drain facility for a nuclear reactor, wherein the length of the coolant drain is set to an upwardly protruding length such that the temperature is reduced to a freezing point and solidified before flowing out of the seal portion to the outside. 11. The coolant drain equipment for a nuclear reactor according to any one of claims 1 to 10, wherein a drive unit of an automatic on-off valve installed on each drain pipe is covered with a heat-resistant protective box. Coolant drain equipment. 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 closing lid having heat insulation and elasticity is attached to the opening window. Facility. 12. 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 operates to close by high heat detection. A coolant drain facility for a nuclear reactor, wherein the coolant drain facility is a normally open type fixed by a tool. 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, a net is installed in the opening window, and a foam type paint having heat insulating performance is applied to the net. Coolant drain equipment for nuclear reactors. 12. The coolant drain system for a nuclear reactor according to claim 11, wherein the protection 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. Facility.

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