JPS61207997A - Nuclear reactor system 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 [Technical Field of the Invention] The present invention relates to nuclear reactor equipment having a residual heat removal system and a reactor coolant purification system, and in particular, to purification of reactor coolant during periodic inspections. This invention relates to nuclear reactor equipment that does not reduce capacity.

[Technical background of the invention]

In general, in boiling water nuclear power plants, in order to maintain the reliability of operating equipment, it is mandatory to periodically stop the operation of the reactor and conduct a comprehensive inspection of the equipment. During this inspection/inspection period (hereinafter referred to as the periodic inspection period), all control rods are inserted into the reactor core and the reactor is shut down. However, even when a nuclear reactor is shut down, decay heat is constantly generated from the reactor core, heating the reactor water. For this reason, even during periodic inspections, the reactor is cooled by the residual heat removal system, while the reactor water continues to be purified by the reactor coolant purification system.

The residual heat removal system 101 and the reactor coolant purification system 102 are constructed as shown in FIG. That is, the residual heat removal system 101 transfers reactor water in the reactor pressure vessel 103 heated by the decay heat of the reactor core to the suction pipe 10.
4 through the residual heat removal pump 105 and cooled by the residual heat removal heat exchanger 106, the heat exchanger outlet piping 1
07, Reactor pressure vessel 1 via heat exchanger return pipe 108
It is configured to return to 03 again. During this operation, if the temperature inside the reactor suddenly changes, a temperature difference may occur between the inner and outer walls of the reactor pressure vessel 103, resulting in large thermal stress. Therefore, due to this thermal stress, the reactor pressure vessel 10
In order to protect No. 3, there is a limit on the rate of decrease in reactor water temperature, which is currently 5°C/hr. Therefore, in order to prevent the temperature of the reactor water returning to the reactor pressure vessel 103 from becoming low, when the residual heat removal system 101 is operating, reactor water is also flowed through the heat exchanger bypass piping 109 that bypasses the heat exchanger 106. By adjusting the opening degrees of the artificial valve 110 and the heat exchanger bypass valve 111, the return humidity of the reactor water is adjusted.

At this time, since the flow rate of the cooling water passed through the heat exchanger 106 is constant, the larger the flow rate without flowing through the heat exchanger 106, the greater the amount of heat removed, and the lower the temperature returned to the reactor pressure vessel 103. On the other hand, the heat exchanger 106 has the ability to remove heat from inside the reactor containment vessel in the event of an accident, so it can perform heat exchange immediately after the reactor is shut down as described above. The water flow a to the heat exchanger 106 is small compared to the discharge amount from the residual heat removal pump 105, and as a result, the heat exchanger artificial valve f
The temperature of the reactor water at f107 is extremely low.

In addition, the reactor coolant purification system 102 includes the reactor pressure vessel 1
Reactor water led from 03 is pressurized by a purification pump 112, cooled by a regenerative heat exchanger 113 and a non-regenerative heat exchanger 114, and then purified by a filtration 1112 salter 115. The reactor water is configured to recover heat again in the regenerative heat exchanger 113 and return to the reactor pressure vessel 103. With this configuration, the resin of the filtration chlorinator 115, which is vulnerable to high temperatures, is protected, and since it is heated again after purification, heat loss during normal plant operation is reduced, and the thermal efficiency of the entire power plant is reduced. can be prevented.

In this way, cooling and purification of the reactor coolant after the nuclear reactor is shut down are performed by separate systems.

As described above, during the regular inspection period, the purification pump 112 is to be disassembled and inspected as one item of the general inspection. As shown in the figure, two purification pumps 112 with a capacity of 50% of the required water supply capacity are arranged in parallel, so that even if one purification pump 112 is stopped, the purification of the reactor water continues. One of the machines is also operated during disassembly and inspection during the inspection period.

In FIG. 2, reference numeral 116 is a recirculation pump for forcedly circulating reactor water within the reactor pressure vessel 103.

[Problems with background technology]

As mentioned above, although the reactor coolant is cooled and purified, the overhaul of the purification pump 112 during the inspection period is
We plan to do this for each vehicle separately. However, when only one unit is operated, its water supply capacity is half of what is required, so the system flow rate is half of the normal flow rate, which unavoidably reduces the purification capacity. In order to switch roads, disassembling and inspecting each vehicle one by one naturally had to lengthen the entire process, which caused various problems.

[Purpose of the invention]

Therefore, the present invention has been developed in view of these circumstances, so that the operation of the two purification pumps can be stopped at the same time and the decomposition of the two purification pumps can be stopped simultaneously without reducing the purification ability of the reactor coolant during the inspection period. The purpose is to provide nuclear reactor equipment that allows quick inspection.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides a nuclear reactor having a residual heat removal system for removing residual heat in the reactor and a reactor coolant purification system for purifying reactor water. In the system equipment, a bypass pipe is provided that connects the downstream side of the residual heat removal heat exchanger of the residual heat removal system to the downstream side of the purification pump of the reactor coolant purification system.

[Embodiments of the invention]

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

FIG. 1 is a system diagram showing the main parts of an embodiment of the present invention,
1 is a reactor pressure vessel. This reactor pressure vessel 1 includes a residual heat removal system 2 that removes residual heat such as decay heat after the reactor operation is stopped, and a residual heat removal system 2 that removes fission products and corrosion products from reactor water, which is a coolant, for purification. The reactor coolant purification system 3 is connected to the reactor coolant purification system 3.

The residual heat removal system 2 connects a suction pipe 4 connected to the reactor pressure vessel 1 with a residual heat removal pump 5 that boosts the pressure of reactor water. Connect the vessel inlet piping 7 and perform residual heat removal heat exchange J! A device 8
Furthermore, the heat exchanger outlet pipe 9 and the heat exchange return pipe 10 are connected from this heat exchanger 8 to form a flow path for reactor water leading to the reactor pressure content 'a1, and the inlet pipe 7 From there, a heat exchanger bypass pipe 12 having a heat exchanger bypass valve 11 is connected to the return pipe 10 .

Therefore, the reactor water in the reactor pressure vessel 1 is transferred to the heat exchanger 8
While it is cooled by heat exchange with cooling water 13 from the outside, a large drop in the temperature of the reactor water can be prevented by mixing it with an appropriate amount of uncooled reactor water from the bypass piping 12.

On the other hand, the reactor coolant purification system 3 has a purification pump inlet valve 15, a purification pump 16, and a purification pump outlet valve 17 connected in parallel to a lower reactor drain pipe 14 connected to the reactor pressure vessel 1. A regenerative heat exchanger 19 is connected to a purification pump outlet pipe 18 connected from the outlet valve 17. A non-regenerative heat exchanger 21 is connected to the heat exchanger connection piping 20 connected from the regenerative heat exchanger 19, and a filtration general increaser is connected to the filtration general increaser inlet piping 22 connected from the non-regenerative heat exchanger 21. Common theory J! ! 24. A return connecting pipe 25 is connected from this filter stone tool 24 to connect it again to the regenerative heat exchanger 19, and a return pipe 26 connected from the regenerative heat exchanger 19 connects it to the reactor pressure vessel 1. . Therefore, the reactor water in the reactor pressure vessel 1 is cooled by the external coolant 27 in the non-regenerative heat exchanger 19, and then purified by the filtration salt generator 24. The resin within 24 is protected from high temperatures and can also prevent a decrease in overall thermal efficiency.

A purification pump bypass pipe 28 is provided to send reactor water from the heat exchanger 8 of the residual heat removal system 2 to the filtration stone 24 of the coolant purification system 3. This bypass pipe 28 is branched from the middle of the outlet pipe 9, and as shown in the figure, is connected to the upstream side of the filter salt mold 24, that is, the upstream side of the filter salt valve 23, and, A gate valve 29 is provided so that the flow path can be opened and opened.

Although not shown, the bypass pipe 28 branched from the outlet pipe 9 can be connected to the purification pump outlet pipe 18 upstream of the regenerative heat exchanger 19 or to the non-regenerative heat exchanger 2.
It may be connected to the heat exchanger connection pipe 20 which is on the upstream side of the heat exchanger 1. According to this, filtered salt! It is possible to ensure complete protection of the resin within 24, and further prevent a decrease in the overall thermal efficiency.

In FIG. 1, reference numeral 30 is a recirculation pump for forcedly circulating reactor water within the reactor pressure vessel 1.

Next, to explain the operation during the regular inspection period of this embodiment, reactor water that passes from the reactor pressure vessel 1 through the suction pipe 4 and is pressurized by the removal pump 5 is partially transferred to the heat exchanger 8. The remaining part passes through the bypass pipe 28 and is purified by the filtration quartz 24, and then returned to the reactor pressure vessel 1 through the return pipe 26. At that time, the distribution between the heat exchanger 8 water flow valve 6 and the heat exchanger bypass pipe 28 is determined by the operator who is monitoring the temperature drop rate of the reactor pressure vessel 1. It is determined by operating the valve 11.

Further, the reactor water flow j cooled by the heat exchanger 8 and sent through the bypass pipe 28 is equal to the normal flow rate in the reactor coolant purification system 3, that is, the water flow rate when the two purification pumps 16 are in operation. Sent to Tero Common Theory Stoneware 24. This allows the purification capacity to be exactly the same as that during normal operation, and does not interfere with the operation.

The purified reactor water is sent to the filtration stone tool 24 through the bypass piping 28 and is returned to the reactor pressure vessel 1 through the return piping 26, where it is combined with the reactor water that is not bypassed.

Therefore, the reactor water cooled in the residual heat removal system 2 can be sent to the filtration stone tool 24 without passing through the purification pump 16. Therefore, by opening and closing each of the artificial valve 15 on the upstream side of the purification pump 16 and the outlet valve 17 on the downstream side, the purification pump 16 can be isolated.

〔Effect of the invention〕

As explained above, the present invention is provided with a purification pump bypass piping that sends reactor water from the residual heat removal heat exchanger of the residual heat removal system to the filtration stone tool of the reactor coolant purification system, so that the purification pump is stopped. Even if the reactor coolant purification system is operated, the purification ability of the reactor coolant purification system is not inferior to that during normal operation, and the purification can be carried out. Moreover, it is possible to prevent a decrease in the purifying capacity during disassembly and inspection of the conventional purifying pump, and it is possible to avoid the deterioration of the purifying capacity during disassembly and inspection of the purifying pump, which has conventionally been forced to be accepted.

In addition, since there is no problem even if all of the purification pumps are stopped, disassembly and inspection can be done all at the same time, greatly reducing the time required for the inspection process. Since it does not operate at all and can be stopped, its overhaul can be carried out at any time, even when the reactor water purification ability needs to be maintained, and work plans can be made freely. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system diagram of an embodiment of nuclear reactor equipment according to the present invention, and FIG. 2 is a system diagram of a conventional example. 1... Reactor pressure vessel, 2... Residual heat removal system, 3...
...Reactor coolant purification system, 4...Suction piping, 5...
Residual heat removal pump, 6... Heat exchanger artificial valve, 7...
Heat exchanger inlet piping, 8... Residual heat removal heat exchanger, 9.
...Heat exchanger outlet piping, 10...Heat exchanger return piping,
DESCRIPTION OF SYMBOLS 11... Heat exchanger bypass valve, 12... Heat exchanger bypass piping, 13... Cooling water, 14... Reactor lower drain piping, 15... Purification pump artificial valve, 16...
Purification pump, 17...Purification pump outlet valve, 18...
Purification pump outlet piping, 19... regenerative heat exchanger, 20.
・・Heat exchanger connection piping, 21 ・・Non-regenerative heat exchanger, 2
2... filtration theory stoneware inlet piping, 23... filtration theory salt inlet valve, 24... filtration theory stoneware, 25... return connection piping,
26... Return piping, 27... Coolant, 28... Purification pump bypass piping, 29... Gate valve, 30...
Recirculation pump, 101... Residual heat removal system, 102...
・Reactor coolant purification system, 103...Reactor pressure vessel,
104... Suction piping, 105... Residual heat removal pump, 106... Residual heat removal heat exchanger, 107... Heat exchanger outlet piping, 108... Heat exchanger return piping, 109
...Heat exchanger bypass piping, 110...Heat exchanger artificial valve, 111...Heat exchanger bypass valve, 112...
Purification pump, 113... Regeneration heat exchanger, 114...
Non-regenerative heat exchanger, 115...filtration deviation stone tool.

Claims (1)

[Claims] 1. In nuclear reactor equipment having a residual heat removal system for removing residual heat in the reactor after the reactor is shut down and a reactor coolant purification system for purifying reactor water, 1. Nuclear reactor system equipment, characterized in that a bypass piping is provided that connects the downstream side of the residual heat removal heat exchanger of the system to the downstream side of the purification pump of the reactor coolant purification system. 2. The reactor system equipment according to claim 1, wherein the flow rate of reactor water sent through the bypass pipe is equal to the normal flow rate in the reactor coolant purification system. 3. The bypass piping is connected upstream of a regenerative heat exchanger, a non-regenerative heat exchanger, or a filtration demineralizer in the reactor coolant purification system, according to claim 1 or 2. Nuclear reactor equipment.