JPS59128488A - Fast breeder - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fast breeder reactor, and particularly to a tank-type fast breeder reactor using sodium as a coolant.

[Prior art]

In a conventional sodium-cooled tank fast breeder reactor,
In addition to the main intermediate heat exchanger that exchanges heat between the primary coolant and the secondary coolant in the reactor main vessel, there is also an auxiliary intermediate heat exchanger that cools the primary coolant in the event of a reactor emergency due to failure of the main cooling system. A container is provided. Figure 1 shows DRAC8 (Djrect
1%reactor Auxiii2ryCool
FIG. 3 is an explanatory diagram of a fast'breeder reactor equipped with an auxiliary core cooling system developed by Ing System.

The reactor main vessel 10 is provided with a roof slab 12 on the upper part for isolating the inside of the reactor from the outside world and for installing reactor internal structures. A partition wall 14 is formed inside the reactor main vessel 10, and a hot plenum 16 is formed inside the reactor main vessel 10.
and cold plenum 18. A reactor core 20 is housed in the center of the reactor main vessel 10, that is, in the center of the bottom of the hot plenum 16. The hot plenum 16 and the cold plenum 18 are filled with primary sodium, which is a secondary coolant, and a cover gas 21 made of an inert gas is sealed above the hot plenum 16 and the cold plenum 18. .

A core upper mechanism 22 for guiding a control rod drive shaft (not shown), a life circulation pump 24, a main intermediate heat exchanger 26, and an auxiliary heat exchanger 28 are suspended from the roof slab 12. ,
A heat exchanger tube 30 is provided in the main heat exchanger 26 so that heat can be exchanged between the primary sodium in the hot plenum 16 and the secondary sodium flowing inside the heat exchanger tube 30. . The secondary sodium flowing through the heat transfer tube 30 is circulated via a superheater 32 and a steam generator 34. The coolant flowing through the auxiliary heat exchanger 28 is generally N a K (an alloy of sodium and potassium) having a low melting point, and is circulated through the auxiliary core cooling system 36 . This auxiliary core cooling system 36 is provided with an expansion kunk 3β that absorbs the expansion of the coolant, and also has an NaK
A cooler 40, a pump 42, and a flow meter 44 are provided for cooling and circulating the water.

On the other hand, the partition wall 14 is provided with a heat shield plate 48 in the circumferential direction, facing the main container side wall 46. And the main container side wall 4
6 and the heat shield plate 48,
The flow paths 54 and 5 of the main vessel wall cooling system 52 are separated by the partition plate 50.
6 is formed. As shown in FIG. 2, this main container wall cooling system 52 includes an upper opening 58 formed in the partition plate 50, a space 59 formed at the upper end of the heat shield plate 48, and a lower opening 60 formed at the lower end. is formed.

The operation of the tank-type fast breeder reactor equipped with the DRAC8 configured as described above is as follows.

The cold primary sodium in the cold plenum 18 is -
It is sent to the reactor core 20 by the biocirculation pump 24 and flows into the hot plenum 16 as high temperature primary sodium.

The high temperature primary sodium in the hot plenum 16 flows into the main intermediate heat exchanger 26 and is cooled by exchanging heat with the secondary sodium flowing in the heat transfer tubes 30 before returning to the cold plenum 18 . The secondary sodium heated by the primary sodium in the main intermediate heat exchanger 26 is transferred to the superheater 32
It is further heated in the steam generator 3 and sent to the steam generators 3 and 4.

After the secondary sodium generates steam for driving a turbine (not shown) in the steam generator 34, it is returned to the main intermediate heat exchanger 26 again.

The main vessel wall cooling system 52 is provided to prevent the main vessel side wall 46 around the hot plenum 16 from becoming high in temperature due to high temperature sodium during the operation of the nuclear reactor as described above. That is, the upper end of the heat shield plate 48 forms a space 59 to prevent heat from the hot plenum 16 from being easily transmitted to the main container side wall 46. The flow path 54 allows low-temperature primary sodium in the cold plenum 18 to flow from below through natural convection or through the primary circulation pump 2.
4 and flows into the channel 56 from the upper opening 58. The primary sodium that has entered the flow path 56 returns to the cold plenum 18 through the lower opening 60, and transports the heat transferred via the heat shield plate 48 to the cold plenum 18.

On the other hand, when the reactor is shut down due to a failure of the main intermediate heat exchanger 26, that is, the main cooling system, the pump 42 of the auxiliary core cooling system 36 is driven, and the water in the hot plenum 16 is pumped through the auxiliary intermediate heat exchanger 28. The primary sodium is cooled and decay heat in the core 20 is removed.

In a nuclear reactor equipped with such a RAC8 type auxiliary core cooling system, it is necessary to provide an independent auxiliary intermediate heat exchanger 28, so there is not a large number of equipment, which increases the size of the reactor itself and makes it difficult to arrange the equipment. PRAC8 (Primary Reactor A), which incorporates a separate cooling system within the main intermediate heat exchanger 26,
There is a fast breeder reactor that uses an auxiliary core cooling system. However, in the case of PAf (, C8), a separate cooling system is incorporated into the main intermediate heat exchanger, which has the disadvantage that the main intermediate heat exchanger becomes large and has a complicated structure.

Despite the drawbacks mentioned above, the installation of an auxiliary core cooling system is essential for ensuring the safety of a nuclear reactor.
It must be installed as ancillary equipment to the reactor. Moreover, since the auxiliary core cooling system is used only for removing core decay heat after a reactor scram caused by a failure of the main cooling system, it is used infrequently and the operating rate of the equipment is extremely low.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a fast breeder reactor that can simplify nuclear reactor equipment.

[Summary of the invention]

The present invention provides an opening that can be freely opened and closed in the partition wall that divides the inside of the reactor main vessel into a hot plenum and a cold plenum, and a heat exchanger that is connected to an auxiliary cooling system in the cold plenum. During operation, it is operated to cool the main container wall, and in the event of a failure of the main cooling system, the opening is opened,
In order to remove the decay heat of the reactor core and allow the main vessel wall cooling system to serve as both the auxiliary core cooling system and simplify the reactor equipment,
It is composed of

[Embodiments of the invention]

Preferred embodiments of the fast breeder reactor according to the present invention will be described in detail with reference to the accompanying drawings.

Note that the same reference numerals are given to the parts corresponding to the parts explained in the prior art, and the explanation thereof will be omitted.

FIG. 3 is an explanatory diagram of an embodiment of a fast breeder reactor according to the present invention. In FIG. 3, the part of the bulkhead 62 that divides the inside of the reactor main vessel 10 into a hot plenum 16 and a cold plenum 18, facing the main vessel side wall 46, is an isolation cylinder 46 concentric with the main vessel side wall 46. It becomes. Annulus portion 6 formed by main container side wall 46 and isolation cylinder 64
6, a heat shielding cylinder 68 is installed, and the annulus part 66
The furnace wall side annulus part 70 and the cylindrical side annulus part 7 are separated from each other.
It is divided into 2. And in the annulus section 66,
A cooling pipe 76 of the auxiliary cooling system 74 is arranged. The cooling pipe 76 is arranged so that the furnace wall side annulus portion 70 and the isolated cylinder side annulus portion 72 are integrally connected. The coolant flowing through the cooling pipe 76 is slightly cooled by an air cooler 78 provided in the auxiliary cooling system 74, passes through the flow meter 44, and returns to the cooling pipe 76 again.

On the other hand, the isolation cylinder 64 has a sodium inlet window 82 formed near its upper end below the sodium liquid level 80 . The sodium inflow window 82 is openable and closable as shown in FIG. That is, a sliding cylinder 86 in which a window 84 is formed is provided on the hot plenum 16 side of the isolation cylinder 64. This sliding cylinder 86 is supported via a drive rod 90 by an expansion joint 88 provided on the roof slab 12.
A drive mechanism 92 provided at the tip of the drive rod 90 is capable of moving up and down along the isolation cylinder 64.

The operation of the auxiliary cooling system in the fast breeder reactor configured as described above is as follows.

During normal operation of the reactor, the sodium inflow window 82
is closed by a sliding cylinder 86 as shown in FIG. The coolant naturally circulating in the auxiliary cooling system 74 is cooled in the air cooler 78 and then flows into the cooling pipe 76 . The coolant of the auxiliary cooling system that has flowed into the cooling pipe 76 exchanges heat with the primary sodium in the cold plenum 18 in the annulus section 66 and is warmed before being transferred to the air cooler 7.
8 and cooled. Therefore, the main container side wall 46 is
Not only is the heat shielding cylinder 68 shielding the heat from the high temperature primary sodium in the hot plenum 16, but also the primary sodium in the annulus portion 66 is cooled by the heat exchange action of the cooling pipe 76, so that it does not reach a high temperature.

On the other hand, when the reactor scrams due to a failure in the main cooling system and the amount of primary sodium flowing into the hot plenum 16 decreases, the drive mechanism 92 is operated as shown in FIG. 82 and open the sodium inflow window 82. When the sodium inlet window 82 is opened, the high temperature sodium in the hot plenum 16 flows into the annulus section 66 through the sodium inlet window 82 and is cooled by the auxiliary cooling system 74 via the cooling pipe 76 . The primary sodium cooled in the cooling pipe 76 is
Due to natural circulation, it flows down from the annulus section 66 to the bottom of the cold plenum 18 and flows back into the hot plenum through the core 20.

By sharing the auxiliary cooling system with the main vessel wall cooling system and the auxiliary core cooling system as described above, the reactor main body can be downsized and simplified, and reliability can be improved.

6 and 7 show other embodiments of the fast breeder reactor according to the present invention. In the fast breeder reactor shown in FIG.
n IJ Song Gooder - Connected to 94°96. That is, the coolant circulating in the auxiliary cooling system is transferred to the ring header 94.
The air flows into the cooling pipe 76 through the ring header 96 and is led to the air cooler 78. With such a structure, the number of pipes passing through the roof slab 12 can be reduced, and by using only one cooling system, the equipment configuration can be simplified.

In the embodiment shown in FIG. 7, the auxiliary cooling system 74 is provided with coolant forced circulation means such as an electrode pump 98. By providing the forced circulation means in this way, the cooling pipe 76
It is possible to reliably ensure the circulation flow rate of the coolant flowing therein, and it is also possible to adjust the flow rate by a small amount commensurate with the amount of cooling. In this embodiment as well, even if the forced circulation means does not operate, such as when the power is lost, heat can be removed by natural circulation.

[Effects of the Invention] As explained above, according to the present invention, the fast breeder reactor can be simplified by sharing the main vessel wall cooling system and the auxiliary core cooling system.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional tank-type fast breeder reactor equipped with a D-type AC8, Figure 2 is a detailed diagram of the main vessel wall cooling system of the tank-type fast breeder reactor shown in Figure 1, and Figure 3 is An explanatory diagram of a fast breeder reactor according to an embodiment of the present invention, FIG. 4 is a sectional view showing a state in which the sodium inflow window provided in the isolation cylinder of the partition wall is closed, and FIG. 5 is a sectional view showing the sodium inflow window in an open state. 6 and 7 are explanatory diagrams of other embodiments of the fast breeder reactor according to the present invention. 10... Reactor main vessel, 14..., 62... Partition wall, 1
6... Hot plenum, 18... Cold plenum, 20... Core, 26... Main intermediate heat exchanger, 28...
...Auxiliary intermediate heat exchanger, 36...Auxiliary core cooling system, 6
4... Isolation cylinder, 74... Auxiliary cooling system, 76...
Cooling pipe, 82...Sodium inlet.し:１：、ノ [door[) 36 2nd 4th ! 5th eye

Claims (1)

[Claims] 1. A reactor main vessel that houses the reactor core, a partition wall that divides the inside of the reactor main vessel into a hot plenum and a cold plenum, and a partition wall that divides the primary coolant in the hot plenum into a secondary coolant and heat. In a fast breeder reactor, the hot plenum formed in the partition wall is provided with a main intermediate heat exchanger that causes the coolant to flow down into the cold plenum while being exchanged, and an auxiliary cooling system that cools the secondary coolant in the event of a reactor emergency. A fast breeder reactor comprising: an opening that can be freely opened and closed to communicate the cold plenum with the auxiliary cooling system; and a heat exchanger that is connected to the auxiliary cooling system and installed inside the cold plenum.