JPS62251695A - Nuclear-reactor container cooling facility - 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 Industrial Application] The present invention relates to reactor containment cooling equipment, and particularly to a reactor containment cooling equipment for a boiling water nuclear power plant.

[Conventional technology]

An example of the system configuration of conventional reactor containment vessel cooling equipment is shown in Part 5.
In Figure 0 shown in the figure, a reactor containment vessel (hereinafter referred to as a dry well) 1 has a reactor pressure vessel 2. -Water cooling system piping 7
．． Primary cooling system isolation valve (or electric valve or air-operated valve with solenoid valve) 10, reactor recirculation pump (motor) 34.
It houses the CRD drive unit G5, etc. Cooling equipment is required to remove the heat radiated from these high-temperature devices and piping.

The cooling equipment uses a cooling coil 12 and a blower 13 that use auxiliary cooling water, cold water, or refrigerant as a cooling source to cool the reactor pressure vessel (hereinafter referred to as RPV) 2 through an air supply duct 14.
Cold air is supplied and circulated to the space between the γ-ray shield and the γ-ray shield (hereinafter referred to as γ-ray shield) 4, the upper part of the dry well, and the RPV top head section 27. After the cooling gas removes heat from these parts, it descends to the lower part of the drywell.

The descending gas stirs and removes heat from the lower part of the dry well and the lower RPV 8, and then is sucked into the lower exhaust ring duct 32 and guided to the cooler (cooling coil, blower) 11.

In addition, as a conventional example regarding dry well cooling equipment,
JP-A-51-35888 and JP-A-57-13619
There is No. 1.

[Problem that the invention seeks to solve]

The inside of the drywell is normally sealed.

Moreover, since the amount of heat dissipated from the equipment, piping, etc. is very large, the size of the cooler and ducts will also be increased.

In addition, the cooling machine includes a blower, which is a dynamic equipment.
For safety reasons, a certain degree of redundancy is required and a standby unit is required, so the proportion of the drywell space occupied by the cooler and ducts is extremely large.

Figure 6 shows a cooling machine installed at 50% each in the upper and lower parts of the drywell.
The diagram shows an outline of the equipment and duct configuration when 3 units are installed. Inside the dry well, there are many piping systems such as the primary cooling water system and electric valves attached to these pipings as shown in Figure 7. They tend to come close to machines and ducts and cause interference.

For this reason, a lot of effort is spent adjusting the arrangement of the two devices and piping, but it is difficult to completely secure maintenance space and passage space, resulting in a loss of workability during periodic inspections.

In this way, in the conventional technology, in addition to equipment and piping such as the primary cooling water system, most of the related isolation valves, electric valves, and air-operated valves are installed inside the dry well, increasing the dry well space ( In order to increase the surface area of high-temperature pipes, etc.), and to maintain the functionality of isolation valves with electrical components, the entire inside of the drywell is kept at a relatively low temperature (e.g., an average of 57
Since no consideration is given to the fact that the two factors of maintaining the temperature at a temperature of 100°F (°C) result in an increase in the heat load inside the drywell, a problem arises in that the drywell cooling equipment becomes larger.

Additionally, in traditional drywell cooling equipment.

There was a problem in that the CRD piping was complicated and the ventilation of the CRD drive unit, which had a complicated structure, was insufficient, resulting in localized high temperature areas in the CRD piping, making it impossible to make the temperature distribution uniform.

This CRD drive section is equipped with a temperature measuring element, and the detected temperature constitutes an interlock such as an alarm or a stop, so it is undesirable for localized high humidity areas to occur.

By the way, in the dry well space, one way to avoid interference or proximity between the cooling device and other equipment or piping, etc., and to secure an effective maintenance space and passage is to install the dry well cooler outside the dry well. However, it is not realistic for the following reasons.

(1) The heat load inside the dry well is extremely large, and considering the capacity (size) and number of coolers, it is difficult to secure space for installing the cooler outside the dry well.

(2) The air supply duct and exhaust duct of the dry well cooler penetrate the dry well, but the air volume is very large, the duct size is also large, approximately 1.5 m to 2 mφ, and the arrangement of the dry well penetration part (penetration) is large. Ga is difficult.

From the above, in order to secure effective passage and maintenance space in the dry well interior space, the amount of heat dissipated from the high temperature equipment and piping surfaces within the dry well itself must be reduced.
Reduce the load on the cooler and make the cooler smaller; install the cooler outside the dry well; and save space as much as possible for the supply and exhaust ducts installed inside the dry well.

Although it is desirable to have a duct structure that makes the temperature distribution of the CRD drive unit as uniform as possible, the above conventional example has the following drawbacks.

JP-A No. 51-35888 (1) Cooler (cooling coil, blower) inside the dry well
Since it requires a start-up air supply duct,
The cooling equipment flange installation space occupies a very large amount of space inside the dry well.

(2) Passing high-temperature gas through the space between the RPV and the γ-ray shield and transferring it from top to bottom goes against the laws of nature, and although possible in principle, it is impractical.

(3) G: The ventilation volume of the RD drive unit is small.

Non-uniformity of attitude tends to occur in the CRD piping complex.

JP-A-57-136191 (1) Since a cooler (cooling coil, blower) is provided within the dry well, the space occupied by the cooler within the dry well is extremely large.

(2) Since the temperature of the cooling gas is low, it stagnates at the bottom.

If the cooler is installed at the bottom, uniform cooling cannot be expected without a startup air supply duct or exhaust duct.

(3) Transferring high-temperature gas from top to bottom through the space between the RPV and the gamma ray shield goes against the laws of nature, and although it is theoretically possible, it is unrealistic. It is.

(4) Since the air volume in the CRD drive drive part is small, the CRD
Temperature non-uniformity tends to occur in piping complexes.

The purpose of the present invention is to reduce the heat load inside the dry well, downsize the dry well cooler, save space for installing the cooler outside the dry well and the duct installed inside the dry well, and improve the reliability of equipment operation. The objective is to provide dry well cooling equipment that can improve the

[Means for solving problems]

In order to achieve the above object, the present invention employs the following means.

(1) An internal pump is used in the recirculation system, and many isolation valves are installed inside the dry well.

Install electric valves, air-operated valves, etc. outside the dry well to reduce the dry well volume.

(2) Divide the inside of the dry well into a medium temperature area (electrical equipment area) and a high temperature area (area excluding the medium temperature area).

(3) Concentrate air supply to the lower part of the RPV pedestal.

(4) A grid plate is provided in the space between the RPV and the γ-ray shield.

[Effect]

Each of the above means contributes to achieving the objective in the following manner.

(1) Reducing the volume of the dry well reduces the surface area of high-temperature piping, etc., and reduces the heat load inside the dry well.

(2) Segmentation of medium and high temperature regions within the dry well reduces the high temperature region and reduces its heat load, thereby reducing the overall heat load within the dry well.

(3) Concentrated air supply to the lower part of the RPV pedestal will increase the ventilation rate in the area and make the temperature distribution uniform.

(4) Installing a grid plate in the space between the RPV and the γ-ray shield increases the separation of the medium temperature region and high temperature region, and
This will improve the rectification of the space between the PV and the γ-ray shield and the effect of the air passage.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The dry well 1 has a concrete support structure 3. centered around the RPV2. γ-ray shield 4゜CRD drive unit w
There is a 151 suppression pool 6, etc., and a large number of piping 7 such as a primary cooling water system are arranged.

The feature of this embodiment is that the internal pump 9 is installed in the lower part 8 of the RPV pedestal, and the isolation valves (or electric valves or air-operated valves with solenoid valves) 10 are all installed outside the dry well.

The above configuration and arrangement bring about the following effects.

First, an internal pump is used in the recirculation configuration, and 'all! The dry well volume can be reduced to 173 mm compared to the conventional one by installing the electrical components of the primary cooling water system, such as the 1 liter valve, electric valve, and air-operated valve, outside the dry well.

Next, due to the reduction in the volume of the dry well, the total length of high-temperature piping such as the primary cooling water system installed in the dry well is shortened, and the surface area is reduced, resulting in a decrease in the amount of heat dissipated from the piping.

Furthermore, in the conventional example, ti! In order to maintain an elegant heat-resistant environment, the average temperature of the entire dry well is set at 57°C (local maximum temperature 65°C). Since the temperature is set at 55°C (medium temperature range) and the other part is set at 110°C (high temperature range), the amount of heat dissipated in the high temperature range is reduced.

Corresponding to the above-mentioned changes to the dry well, the dry well cooling device has the following configuration. Dry well cooler 11 installed outside the dry well (cooling coil 12, blower 1
3), the atmospheric gas in the dry well is cooled, and the air supply duct 14. RPV pedicle lower part 8 through air outlet 15
After cooling the CRD drive unit T15 and internal pump 9 intensively, the gas is transferred to the space 18 between the RPV and the γ-ray shield 4 via the grid plate 17. On the other hand, the γ-ray shield 4 and the γ-ray shield insulation board 1
9, a branch duct 21 of the air supply duct 14 is provided.
Cooling gas is supplied from

Gas 2 transferred to the space 18 between the RPV and the γ-ray shield
After removing heat from each space, the gas 23 supplied to the space 20 between the γ-ray shield and the γ-ray shield insulation board diffuses into the upper part of the dry well, and passes through the suction port 24 provided at the upper part of the dry well. It is sucked into the suction ring duct 25,
It is recirculated to the dry well cooler 11 via the exhaust duct 26.

In addition, in order to prevent the high temperature gas from stagnation in the RPV top head 27, a dedicated suction port 28. An exhaust duct 29 is provided. Furthermore, the air supply duct 14 and the exhaust duct 26 are provided with two isolation valves 30, 31 each in series.

The purpose of supplying cooling gas to the space between the γ-ray shield and the γ-ray shield insulation board is to maintain the temperature of the space below 65°C and prevent high-temperature deterioration (moisture reduction) of the γ-ray shield (concrete). It is.

Next, the grid plate 17 will be explained with reference to FIGS. 2 and 3.

The grid plate 17 is placed in the space between the RPV and the γ-ray shield.
It is installed at an angle and has the following functions. The temperature region within the dry well is divided into a medium temperature region (lower part of the RPV pedestal where electrical equipment such as internal pumps are installed) and a high temperature region (region excluding the medium temperature region). Lattice plate 1
In order to temporarily confine the gas that is intensively supplied to the lower part of the RPV pedestal by using the resistor 7, the temperature of the CRD drive unit i25 where the CRD piping is complicated is made uniform, and the transferred air is connected to the RPV and the γ-ray shield. It can be evenly supplied to the space.

In this embodiment, the air volume of the dry well cooler can be calculated as follows. Note that in this calculation, the air volume was calculated by including the space between the γ-ray shield and the γ-ray shield insulation board in the space between the RPV and the γ-ray shield, but it is different from the value calculated using a strict formula. The difference is small.

L- is 22, Qw Nidrywell cooler air volume (m'/h) q^:
Space between RPV and γ-ray shield in the example (wind duct)
Calorific value (kca Q / h) qB = Calorific value in the dry well excluding the calorific value of the lower part of the RPV pedestal in the example and q^ (kca Q / h) q'^: The difference between the RPV and the γ-ray shield in the conventional example Space calorific value (22G, 000kca Q/h)q
I, a Calorific value in the lower part of the RPV pedestal in the conventional example and calorific value in the dry well excluding q'^ (520,000 kca Q/h)
T: Reactor water temperature in the raw water reactor (272°C) t: Ambient temperature inside the dry well in the conventional example (57°C)
) t^: Space between RPV and γ-ray shield in the example (
temperature ('C) of the RPV pedestal lower part (55
℃) and the temperature inside the dry well excluding the space between the RPV and the gamma ray shield (110 ℃) C Specific heat of the atmospheric gas inside the dry well (0.28 kcaA/m'' ℃) K: Dry temperature of the conventional example and the example Well volume ratio (2/3) In equations (1), (2), and (3) above, q'^tq'BeT+
t e t' 81 By substituting the values of c and K, we get
Qw=29,600ma/h and t^=78.5°C are obtained.

Moreover, the supply air temperature t' to the lower part of the RPV pedestal is calculated as follows.

QwX smile, tc: Ambient temperature at the bottom of the RPV pedestal (55℃) qc: Calorific value at the bottom of the RPV pedestal (60,000℃)
kca Q/h) Therefore, t'=47. sf, press 4
The temperature will be 8℃.

In addition, the heat load inside the dry well in the example is q^+ q
a+ qc=198,000+261,000+60,
000″=520+0OOkca Q/h.

From the above, in the example, compared to the comparative example, the heat load inside the dry well was reduced by 60%, and the air volume of the cooler (in the conventional example, it was 17%).
4,000 m'/h) by 83%, the cooler can be made smaller and installation space can be secured outside the dry well. Furthermore, due to the reduction in air volume, the size of the supply and exhaust ducts is reduced to about 500 mφ to 600 mφ, making it easy to secure the dry well penetration portion of the ducts.

According to this embodiment, the following effects can be obtained.

(1) In the conventional example, it was impossible to perform normal maintenance on the isolation valves, electric valves, air-operated valves, and coolers (air blowers) installed in the closed dry well, but in the example, these Because the equipment is installed outside the drywell,
Maintenance becomes possible and reliability of single equipment operation is improved.

(2) Supply by reducing the air volume of the dry well cooler.

The size of the exhaust duct can be reduced, and the space between the RPV and the γ-ray shield can be used as an air passage, eliminating the need for a conventional air supply startup duct, significantly reducing the space required for installing the duct inside the dry well. This is possible, and due to the synergistic effect with the above reliability improvement, sufficient maintenance space and passages for other equipment and piping can be secured in the dry well interior space.

(3) Uniform temperature distribution at the bottom of the RPV pedestal:
False alarm (AN
N), and also suppress the temperature rise to about 10°C even when the heat load increases during reactor scram, so by setting the allowable temperature of the internal pump to 65°C, it is possible to This eliminates the need for the increased air operation mode, which simplifies the operation and operation of the cooling device.

(4) The dry well cooler has an inlet gas temperature of 110°C.
Since the outlet gas temperature is approximately 48°C, reactor auxiliary cooling water (15 to 35°C) is sufficient as the cooling water for the cooling coil.
Unlike the conventional example, since the cooler air volume is reduced (the outlet gas temperature is lowered), there is no need to install a refrigerator, making it economical.

Furthermore, the cooler and duct can be made smaller.

The equipment cost of the entire cooling device can be reduced to 1/1 degree of that of the conventional example.

Next, a modification of the embodiment shown in FIG. 1 is shown in FIG. 4.

The difference between this example and the example shown in FIG. 1 is that the dry well cooler is installed at the bottom 8 of the RPV pedicle. Qm and the exhaust ring duct 32 was installed at the bottom of the dry well.

In the case of the embodiment shown in FIG. 1, an air supply duct 14 is required to draw cold air from the dry well cooler 11 to the lower part of the pedicle.
All you need to do is install a vibrator that discharges the waste heat absorbed by the system to the outside, making it even more efficient in terms of space.

〔Effect of the invention〕

According to the present invention, the dry well volume can be reduced, the temperature inside the dry well can be divided into a medium temperature region and a high temperature region, and the heat load inside the dry well can be reduced. Also.

Cooling gas is collected and supplied to the lower part of the RPV pedestal, and after cooling this part, it is transferred to the upper part of the dry well using the lattice plate and air passage (the space between the RPV and the gamma ray shield). It has become possible to downsize the cooler and install it outside the dry well, and it is also possible to install it outside the dry well.
The temperature distribution at the bottom of the pedestal can be made uniform.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the system configuration of an embodiment of the reactor containment cooling equipment according to the present invention, and FIGS. 2 and 3 are diagrams explaining the function of the grid plate of the cooling equipment shown in FIG. Fig. 4 is a diagram showing a modification of Fig. 1@Embodiment, Fig. 5 is a diagram showing a system configuration of an example of conventional dry well cooling equipment, and Fig. 6 is a diagram showing a cooling machine and duct of the cooling equipment shown in Fig. 5. FIG. 7, a diagram showing the arrangement, is a perspective view showing an outline of the electric valve installed in the primary cooling water system. 1... Reactor containment vessel (dry well), 2... Reactor pressure vessel, 3... Concrete support structure, 4
... γ-ray blocking body (shield), 5... CRD drive device, 6... Suppression pool, 7... Piping for primary cooling water system, etc., 8... Lower part of RPV pedicle,
9... Internal pump, 10... Primary cooling water system isolation valve, ``ff1 valve, air operated valves, 11...
Dry well cooler, 12... Cooling coil, 13...
·Blower. 14... Air supply duct, 15... Air outlet, 16...
Cooling gas, 17... Grid plate, 18... Space between RPV and gamma ray shield (air duct), 19... Gamma ray shield insulation board, 20... Gamma ray shield and gamma ray shield insulation board 21... Branch duct of the air supply duct 14, 22... Gas transferred to the space between the RPV and the γ-ray shield, 23... The γ-ray shield and the γ-ray shield insulation board. Cooling gas supplied to the space, 24...Drywell upper suction port, 25...Drywell upper suction ring duct, 25...Exhaust duct, 27...R
Pv top head, 28...RPV top head gas inlet, 29...RPv top head exhaust/low exhaust duct 0...supply air isolation valve, 31...exhaust isolation valve. 32... Drywell lower exhaust ring duct, 33.
...Drywell lower air inlet, 34...Reactor recirculation pump, 35...Drywell upper air supply ring duct, 36...RPV upper air supply ring duct, 37...
RPV top head air supply ring duct, 38...
Drywell lower cooler, 39...Drywell upper cooler.

Claims (1)

[Claims] 1. Reactor pressure vessel whose sides are surrounded by gamma ray shielding bodies, primary cooling system piping equipped with isolation valves, reactor recirculation pump, and C
In the reactor containment cooling equipment for removing heat emitted from the equipment, piping, etc. that becomes high temperature in the reactor containment vessel housing the RD drive device, the recirculation pump is disposed at the lower part of the pressure vessel. The isolation valve for the primary cooling system piping is located outside the containment vessel, and the medium-temperature area at the bottom of the pedestal where the internal pump and CRD drive device, etc. located at the bottom of the pressure vessel is located. A lattice plate separating the high-temperature area from other areas is installed in the air passage below the pressure vessel and the gamma ray shielding body surrounding it, and a cooler is installed outside the reactor containment vessel, and cooling gas from the cooler is provided. A nuclear reactor comprising: a duct for centrally supplying air to the lower part of the pedestal; and exhaust dust that ascends the air passage after cooling the lower part of the pedestal and returns the cooling gas that cooled the high temperature area to the cooler. Containment vessel cooling equipment.