JPS63157100A - Nuclear-reactor auxiliary 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] [Purpose of the invention] (Industrial application field) The present invention relates to a nuclear reactor auxiliary cooling equipment for a nuclear power plant.

(Prior Art) Nuclear power plants are provided with reactor auxiliary equipment cooling equipment for the purpose of cooling various equipment during normal operation, removing reactor residual heat in an emergency, and cooling an emergency opening lid.

As shown in FIG. 3, this reactor auxiliary equipment cooling equipment is configured such that a reactor auxiliary equipment cooling pump 2 supplies cooling water to a cooling load 1, and heat is removed from the cooling load 1 with the cooling water. The cooling water leaving the cooling load 1 flows into the reactor auxiliary equipment cooling heat exchanger 3 through the cooling water return pipe 5 and the cooling water population valve 6. In this heat exchanger 3, heat is removed from the cooling water by the seawater supplied from the seawater pump 10, and the cooling water exiting the heat exchanger 3 passes through the cooling water outlet valve 7 and the cooling water supply pipe 4, and is cooled again. W is introduced into load 1.

Additionally, a surge tank 12 is provided in the reactor auxiliary equipment cooling equipment for the purpose of replenishing cooling water that decreases in volume due to changes in cooling water temperature and leaks from seals such as valve glands. As shown in Fig. 4, this surge tank 12 is kept at a water level of 11 m so that the normal water level is 18, and when the water level drops to the make-up water start level 19 due to leakage from the seal, etc., the make-up water supply line 13 is Make-up water is supplied, and when the water level rises to make-up water stop level 17, the supply of make-up water is stopped. Note that the flow rate of make-up water from the make-up water supply inlet 13 is adjusted to a maximum of about 9 m'/hr in consideration of the drainage capacity of the drain funnel 15 connected to the overflow 14 of the surge tank 12. The water level in the surge tank 12 is constantly monitored for the purpose of detecting breaks in equipment, piping, etc. For example, if the water level rises to a high water level 16, the water level in the surge tank 12 is constantly monitored. It is determined that fluid has flowed from the load 1 side to the cooling water circulation line side, and an alarm etc. is issued. In addition, if the water level drops to low water level 20, it is determined that the cooling water has leaked to the outside due to a break in the pipe, etc.
A warning etc. will be issued.

In such a reactor auxiliary cooling equipment, a plurality of reactor auxiliary cooling heat exchangers 3 are installed in one system, and maintenance of the reactor auxiliary cooling heat exchangers 3 is required even when the system is in operation. It is now possible to implement. When performing maintenance on the reactor auxiliary equipment cooling heat exchanger 3, first check the cooling water inlet valve 6. Cooling water outlet valve7. Disassemble and inspect the heat exchanger 3 after draining the water inside the heat exchanger 3 using the pieces of the seawater inlet valve 8 and seawater outlet valve 9 as screws.

In addition, when filling the heat exchanger 3 with water after maintenance, first open the bend valve 11, then slightly open the open cooling water inlet valve 6, and then gradually fill the heat exchanger 3 with cooling water. Fill the area with water by letting it flow in.

In this case, the flow rate of cooling water flowing into the heat exchanger 3 needs to be lower than the flow rate of makeup water to the surge tank 12 (9 m3/hr), but the cooling water population valve 6 has a relatively large diameter (400 m3/hr) or less.
It is often a gate valve of grade A). Therefore, it is extremely difficult to adjust the valve opening degree of the cooling water valve 6 so that the flow rate of cooling water to the heat exchanger 3 is 9 m"/hr or less.
The valve opening becomes more open than necessary, and heat exchanger 3
There is a possibility that the flow rate of cooling water to the surge tank 12 may exceed the flow rate of make-up water to the surge tank 12.

In this way, when the reactor auxiliary equipment cooling heat exchanger 3 is filled with water, if the flow rate of cooling water to the heat exchanger 3 exceeds the flow rate of make-up water to the surge tank 12, the water level of the surge tank 12 is maintained at the normal water level 18. This may result in a low water level warning signal or a pump stop signal being issued.

(Problems to be Solved by the Invention) As described above, in the conventional reactor auxiliary cooling equipment, when filling the reactor auxiliary cooling heat exchanger 3 with water, the water level of the surge tank 12 is set to 18 There was a possibility that the decrease would be even greater, which could affect the operation of the plant.

The present invention was made by focusing on these problems.
The purpose is to provide a reactor auxiliary equipment cooling facility that can fill a reactor auxiliary equipment cooling heat exchanger with water without significantly lowering the water level of the surge tank.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides bypass piping that bypasses the cooling water inlet valve in the cooling water inlet line of the reactor auxiliary equipment cooling heat exchanger. In addition, the bypass piping is provided with an on-off valve so that the flow rate of cooling water to the heat exchanger is equal to or less than the flow rate of make-up water to the surge tank.

(Function) In the present invention, when filling the reactor auxiliary equipment cooling heat exchanger with water, cooling water flows into the heat exchanger through bypass piping, thereby controlling the flow rate of cooling water to the heat exchanger to the surge tank. The make-up water flow rate can be less than or equal to

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Note that parts that are the same as those in the prior art are given the same reference numerals, and their explanations will be omitted. FIG. 1 is a schematic configuration diagram of a nuclear reactor auxiliary cooling equipment showing an embodiment of the present invention. A bypass pipe 22 is provided to bypass the artificial valve 6, and the bypass pipe 22 is further provided with an on-off valve 23 having a small diameter (about 25A). Therefore, when filling the reactor auxiliary equipment cooling heat exchanger 3 with water, the bend valve 11 and the on-off valve 23 are opened to allow cooling water to flow into the heat exchanger 3 through the bypass pipe 22. At this time, heat exchanger 3
The flow rate of cooling water flowing into the surge tank 12 is reduced by the throttling effect of the on-off valve 23 (9 m3/hr).
The water level in the surge tank 12 is set to the normal water level 1.
It can be kept at 8.

As described above, in this embodiment, the bypass piping 22 that bypasses the cooling water inlet valve 6 is provided on the cooling water inlet side of the reactor auxiliary equipment cooling heat exchanger 3, and this bypass piping 22
By providing a small-diameter opening/closing valve 23 in which the cooling water flow rate of the heat exchanger 3 is lower than the make-up water flow rate to the surge tank 12, the water level of the surge tank 12 can be maintained at the normal water level 18. The reactor auxiliary equipment cooling heat exchanger 3 can be filled with water without significantly lowering the water level of the reactor auxiliary equipment cooling heat exchanger 3.

In the above embodiment, the reactor auxiliary equipment cooling heat exchanger 3 was filled with water through the bypass pipe 22, but the second
As shown in the figure, an external supply line 24 is connected to the cooling water return pipe 5 between the reactor auxiliary equipment cooling heat exchanger 3 and the cooling water population valve 6, and the cooling water is supplied from the external supply line 24 to the heat exchanger 3. It may also be made to flow directly into the interior.

[Effects of the Invention] As explained above, according to the present invention, it is possible to fill the reactor auxiliary equipment cooling heat exchanger with water without significantly lowering the water level of the surge tank, and various problems caused by a drop in the water level of the surge tank can be carried out. It is possible to prevent the harmful effects of

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a reactor auxiliary cooling equipment showing one embodiment of the present invention, Fig. 2 is a schematic diagram of a reactor auxiliary cooling equipment showing another embodiment of the invention, and Fig. 3 4 is a schematic configuration diagram of a conventional nuclear reactor auxiliary cooling equipment, and FIG. 4 is a sectional view showing the normal water level of a surge tank. 1... Cooling load, 2... Reactor auxiliary equipment cooling pump, 3
...Reactor auxiliary equipment cooling heat exchanger, 6...Cooling water population valve, 7...Cooling water outlet valve, 12...Surge tank, 2
2...Bypass piping, 23...Opening/closing valve. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A reactor auxiliary equipment cooling pump that supplies cooling water to the cooling load;
A reactor auxiliary equipment cooling heat exchanger that cools the return cooling water from the cooling load with sea water, and a cooling water circulation that circulates the cooling water flowing out from the heat exchanger via the reactor auxiliary equipment cooling pump and the cooling load. In the reactor auxiliary equipment cooling equipment, the cooling water inlet of the heat exchanger is equipped with a surge tank that supplies cooling water to the cooling water circulation line, and a makeup water supply line that supplies makeup water to the surge tank. A nuclear reactor characterized in that a bypass piping that bypasses a cooling water inlet valve is provided in the line, and an on-off valve is provided in the bypass piping so that the flow rate of cooling water to the heat exchanger is equal to or less than the flow rate of make-up water to the surge tank. Auxiliary cooling equipment.