JPS60260885A - Tank type fast breeder reactor - 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 [Technical Field of the Invention] The present invention relates to a tank-type fast breeder reactor in which a core support structure is suspended from a roof slab into a main vessel.

[Technical background of the invention]

In general, fast breeder reactors that use liquid metal as a coolant are roughly divided into tank type and loop type depending on the reactor structure, and those in which an intermediate heat exchanger and circulation pump are installed in the main vessel are called tank type. , and others are called loop types. Generally, when a tank-type fast breeder reactor has an electric output equivalent to 1 million KWe, the diameter of the main vessel is larger than that of a loop-type fast breeder reactor, so there is a risk that the vertical displacement of the roof slab will be large in the event of an earthquake. For this reason, in conventional tank-type fast breeder reactors that support the reactor core from the bottom or side of the main vessel, the control rods may be pulled out excessively due to the vertical relative displacement between the roof slab and the reactor core that occurs during an earthquake. This is unfavorable in terms of ensuring the integrity of the furnace. Therefore, in order to minimize the vertical relative displacement between the roof slab and the reactor core during an earthquake, a tank-type fast breeder reactor has been proposed in which the core support structure is suspended from the roof slab into the main vessel.

FIG. 3 is a cross-sectional view of a tank-type fast breeder reactor showing one example, and 1 in the figure is the main vessel. At the upper end of this main container 1 is a roof slab 2 consisting of a fixed plug 2a and a rotating plug 2b.
is installed to close the upper end opening of the main container 1. This roof slab 2 is equipped with an intermediate heat exchanger 3, a circulation pump 4, a core upper mechanism 5, a fuel exchanger 6, etc., and the intermediate heat exchanger 3 and circulation pump 4 are arranged alternately along the circumferential direction of the roof slab 2. Multiple units are installed. Inside the main vessel 1, a core support structure 7 is connected to a roof slab 2 via a cylindrical suspension shell 8.
More suspended. A core 9 consisting of a large number of fuel assemblies is housed and supported within this core support structure 7. In addition, the inside of the main container 1 is provided with an upper high-temperature Na portion (
It is divided into a hot pool) 11 and a lower low temperature Na part (cold pool) 12. The coolant (liquid sodium) in the main melter 1 is usually about 35% in the cold boule 12.
The temperature is approximately 0° C., and it is sucked in through the inflow hole 13 of the circulation pump 4 and sent to the high-pressure plenum structure 14 below the reactor core 9. The coolant fed into the high-pressure blennium structure 14 is
It passed through Ueno, and at that time, the nuclear reaction heat of reactor core 9 caused about 5
The temperature rises to around 00℃ and the hot pool 11 inside the hanging shell 8
leaks to. The coolant flowing into the hot pool 11 passes through the flow hole 15 formed in the suspension shell 8 and enters the inlet hole 16 of the intermediate heat exchanger 3, where it exchanges heat with the coolant on the secondary side and reaches a temperature of about 350°C. After being cooled to a temperature of 100 mL, it returns to the cold boule 12 through the outlet nozzle 17.

[Problems with background technology]

Incidentally, in such a tank-type fast breeder reactor, the core support structure 7 and the roof slab 2 are connected via the suspension shell 8, so that the core support structure 7 and the roof slab are protected against vertical displacement during an earthquake. 2 move up and down in unison, and the control rods have the advantage of not being excessively pulled out of the core 9. However, if there is any abnormality in the suspension structure 8 or the core support structure 7. It could not be detected at any time, and the reactor's integrity could be compromised.

[Purpose of the invention]

The present invention was made in view of these circumstances, and its purpose is to provide a safe and reliable tank-type high-speed breeder that can detect any abnormality in the hanging shell or core support structure. The goal is to provide a furnace.

[Summary of the invention]

In order to achieve the above object, the present invention includes a main vessel, a roof slab that closes the upper end opening of the main vessel, a core support structure suspended within the main vessel from the roof slab, and a core support structure that is suspended from the roof slab into the main vessel. A sensing rod that penetrates the structure and reaches the bottom of the main vessel and has an arm below the core support structure that comes into contact with the lower end of the core support structure. A refueling machine that is brought into contact with the lower end, a stroke measuring device that measures the stroke of the refueling machine, a suspension shell that suspends and supports the core support structure from a roof slab, and disposed above and below and in the circumferential direction of the inner wall of the suspension shell. a bench marker, a slit corresponding to the bench marker formed in the thermal liner inside the suspension barrel, and a coolant see-through device for measuring the position of the bench marker through the slit. be.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

1 and 2 are diagrams showing one embodiment of the present invention, in which the same parts as in FIG. 3 are given the same reference numerals. In FIG. 1, reference numeral 101 is a sensing rod that measures the position of the core support structure 7.

A plurality of sensing rods 101 are arranged on the outer side of the core support structure 7, and penetrate through the core support structure 7 to reach the bottom of the main vessel 1. A support stand IC) 2 is provided at the bottom of the main container 1 to support the lower end of the sensil rod 101. Further, at a position below the core support structure 7 of the sensing rod 101, an arm portion 103 protruding in the horizontal direction is provided.
is provided. This arm portion 103 is attached to the core support structure 7
The sensing rods 101 and 104 are provided at a constant distance from each other and are spaced apart from each other at a constant distance from the measuring plate 104 attached to the lower end of the sensing rod 101.
By pulling it upward, it comes into contact with the measuring plate 104. Further, a handling head 105 for pulling the sensing rod 101 upward is provided at the upper end of the sensing rod 101. This handling head 105 is gripped by a gripper 6a provided at the tip of the fuel exchanger 6, and is pulled up by the vertical stroke of the gripper 6a.

Furthermore, a scale portion 6b is carved on the top of the fuel exchanger 6 to measure the vertical stroke of the gripper 6a.
This scale portion 6a is designed to be measured by a stroke measuring device 106 installed on the top surface of the roof slab 2.

On the other hand, as shown in FIG.
A bench marker 107 is provided for identifying the position when abnormal deformation or the like occurs in the reactor core support structure 7 or the reactor core support structure 7. The bench markers 107 are arranged at several locations on the upper and lower sides of the inner wall of the hanging barrel and in the circumferential direction, and are vertical bench markers 107a.

107, b, and 107c are arranged at regular intervals.

Further, a thermal liner 108 is provided inside the hanging body 8, and a vertically long slit 109 is formed in the thermal liner 108 at a position facing the bench marker 107. Further, near the side of this slit 109, a scale portion (not shown) is carved in the vertical direction. Furthermore, a sodium fluoroscopy device 110 is installed on the top surface of the roof slab 2 to measure the position of the bench marker 107 through the slit 109. This sodium fluoroscope 110 is equipped with an ultrasonic sensor 111 at its tip, and the position of each bench marker 107 can be measured by reading the scale near the slit 109 with the ultrasonic sensor 111. Further, a packet 112 is provided on the upper part of the suspension barrel 8, and a bench marker 107 is provided at the upper end of this packet 112. In the figure, reference numeral 113 is a liquid level measurement sensor that measures the coolant liquid level within the packet 112.

Next, the operation of this embodiment configured as described above will be explained.

During an in-service inspection after a nuclear reactor has been shut down, first grasp the upper end of the sensing rod 101 with the gripper 6a of the fuel exchanger 6, and place the tip of the sensing rod 101 on the support stand 10.
2, and the position of the core support structure 7 from above the roof slab 2 is measured using the stroke measuring device 106 at the scale portion 6b of the fuel exchange t16. Next, the fuel exchanger 6 is operated to pull the sensing rod 101 upward, and the bowl portion 103 of the sensing rod 1o1 is brought into contact with the measurement plate 104. Then, the position is measured by the stroke measuring device 106 in the same manner as described above. Connect this to all sensing rods 1
01 and compared with values previously measured at the initial stage of reactor operation. Thereby, if there is any abnormality in the suspension shell 8 or the core support structure 7, it can be detected. If any abnormality is detected in the measurement, the sodium fluoroscope 110 reads the scale provided on the side of the slit 109, and the suspension body 8 is
Its location at can be identified. For example, if the measured value of bench marker 107H is normal and the measured values of bench markers 107b and 107G are abnormal as shown in FIG.
It can be determined that there is some abnormality in area C between 07C.

As described above, according to this embodiment, the position of the core support structure 7 during the service life of the nuclear reactor is determined by the sensing rod 101.
By measuring this, it becomes possible to detect excessive strain or abnormal deformation occurring in the suspension shell 8 or the core support structure 7. Further, according to the present embodiment, the soundness of the hanging body 8 from thermal stress can be ensured by constantly measuring the coolant liquid level in the bucket l-112 with the liquid level measurement sensor 113.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a main container, a roof slab that closes the upper end opening of the main container,
A core support structure suspended from the roof slab into the main vessel, and an arm that penetrates the core support structure to reach the bottom of the main vessel and abuts the lower end of the core support structure below the core support structure. a refueling machine that grips the upper end of the sensing rod and brings the arm into contact with the lower end of the core support structure; a stroke measuring device that measures the stroke of the fuel exchanger; A hanging cylinder suspended from a slab, bench markers arranged vertically and circumferentially on the inner wall of the hanging cylinder, slits corresponding to the bench markers formed in a thermal liner inside the hanging cylinder, and the slits. Since it is equipped with a coolant fluoroscopic device that measures the position of the bench marker through the We can provide tank-type fast breeder reactors.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention.
The figure is a sectional view showing a part of a tank-type fast breeder reactor, FIG. 2 is a sectional view showing a part of a hanging shell, and FIG. 3 is a sectional view of a conventional tank-type fast breeder reactor. 1... Main vessel, 2... Roof slab, 3... Intermediate heat exchanger, 4... Circulation pump, 5 Inner core upper i structure, 6
... Fuel exchanger, 7... Core support structure, 8...
Hanging shell, 9... Core, 101... Sensing rod, 106... Stroke measuring device, 107... Benchmer 1-1110... Sodium fluoroscopy device. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A main vessel, a roof slab that closes the upper end opening of the main vessel, a core support structure suspended from the roof slab into the main vessel, and a core support structure that penetrates the core support structure and reaches the bottom of the main vessel. A sensing rod having an arm below the core support structure that contacts the lower end of the core support structure; a fuel exchanger that grips the upper end of the sensing rod and brings the arm into contact with the lower end of the core support structure; and the fuel exchanger. a stroke measuring device for measuring the stroke of the core support structure, a suspension shell that suspends and supports the core support structure from a roof slab, bench markers disposed above and below and in the circumferential direction of the inner wall of the suspension shell, and bench markers corresponding to the bench markers. A tank-type fast breeder reactor comprising: a slit formed in a thermal liner inside the hanging barrel; and a coolant see-through device that measures the position of the bench marker through the slit.