JPS6134496A - Cooling system facility for nuclear 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] [Field of Application of the Invention] The present invention relates to a nuclear reactor cooling system equipment, in particular, a nuclear reactor pressure vessel and a subreduction chamber, a residual heat removal system, a high pressure core spray system, a low pressure core This article relates to a nuclear reactor cooling system equipped with a SBRAY system and a boric acid water injection system.

[Background of the invention]

Nuclear power plants are equipped with reactor cooling system equipment such as a residual heat removal system, a high-pressure core spray system, a low-pressure core spray system, and a boric acid water injection system.

Figure 2 shows a conventional residual heat removal system, where 1 is the reactor pressure vessel, 2 is the reactor containment vessel (hereinafter referred to as the containment vessel), 3 is the subreduction chamber, and 4 is the residual heat removal system (
RHR) heat exchanger, 5 is the RHR pump, 6.7 and 8 are the cooling mode suction piping at shutdown, respectively, from the containment vessel outer isolation valve to the loop branch point or 1,
and after the loop branch point. 9 is the pump suction piping, 10 is the pump discharge piping, 11 is the low pressure water injection mode injection piping, 12 is the cooling mode return piping at the time of shutdown after the isolation valve outside the containment vessel, 13 and 14 are the cooling motor head spray piping at the time of shutdown, The upstream side of the isolation valve on the outside of the containment vessel and the area after the isolation valve on the outside of the containment vessel are shown, respectively. 15 is suppression boule water cooling mode piping, 16 is containment vessel (dry well) cooling mode piping, 17 is containment vessel (subpression chamber) cooling mode piping, and 18 is test piping.

This residual heat removal system has 3 series, consisting of 3 pumps, 2 heat exchangers, piping, valves, supports, etc. 9 In the event of a loss of coolant accident, the suppression pool water is transferred to the RHR pump in low pressure water injection mode. 5 and injected into the reactor pressure vessel 1 shroud. Furthermore, during operation in the containment vessel cooling mode, suppression pool water is absorbed by the R, H tank pump 5, cooled by the R, HR heat exchanger 4, and then sprayed into the containment vessel 2. During operation in the shutdown cooling mode, reactor water is taken out from the recirculation pump inlet piping via the shutdown cooling mode suction piping 6°7.8, is pressurized by the RHR pump 5, and is pressurized by the RHR heat exchanger 4. After cooling, a closed loop circulation circuit is formed which returns to the recirculation pump discharge piping. In addition, when operating in the suppression pool water cooling mode, the suppression pool water is sucked by the RHR pump 5, cooled by the heat exchanger 4, and then returned to the suppression chamber 3 via the test pipe 18. The operation test performed using the test pipe 18 is operated single-handedly from the central control room. During normal operation, the pipe is branched from the pump discharge piping 10 so that the system capacity can be A test pipe 18 is installed to return the entire amount of water to the suppression pool, and it is also possible to test the operation of the valves necessary for injection. Also,
In order to simulate the injection pressure during the test, a throttle valve and a pressure reducing orifice are installed in the test pipe 18.
8 uses suppression pool water cooling mode piping 15.

Figure 3 shows a conventional high-pressure core spray system.
The same parts as in the figure are given the same symbols, 19 is the condensate storage tank (C8T), 20 is the high pressure core spray system (
HFO2) pump, 21 is the HPCS pump suction pipe (C
8T side), 22 is HPC8 pump suction piping (subrection chamber side), 23 is HPC8 pump discharge piping, 2
4 is an injection pipe, 25 is a test pipe (C8T side), and 26 is a test pipe (subrection chamber side).

This high-pressure core spray system is installed as part of the emergency core cooling system and includes one pump, piping, and valves.

Consists of support, etc. This system boosts the pressure of condensate storage tank 19 water or suppression pool water using an HPCS pump 20 and injects it into the reactor pressure vessel 1 shroud.In the event of a loss of coolant accident, the reactor core is depressurized, spray cooled,
It is now possible to re-flood. Then, a test pipe 25 is installed that branches from the HPC8 pump discharge pipe 23 and returns to the condensate storage tank 19 so that a functional test can be performed using water from the condensate storage tank 19 without injecting it into the reactor during normal operation. Along with the installation, it is now possible to test the operation of the valves necessary for water injection. This test pipe 25 is equipped with a throttle valve and a pressure reducing orifice in order to simulate the injection pressure during testing. In addition, a test pipe 26 is installed that branches off from the RPC8 pump discharge pipe 23 and returns to the subrepression chamber 3 in order to perform a functional test using the subrepression chamber 3 as a water source.
Furthermore, a restrictor valve and a pressure reducing orifice are installed in this test pipe 26 in order to simulate the injection pressure during the test.

Figure 4 shows a conventional low-pressure core spray system.
The same parts as in Figures and Figure 3 are given the same numbers)
, 27 is the low pressure core spray system (LP01) pump, 2
8 and 29 indicate LPC8 pump suction piping, respectively, up to the subrepression chamber outlet isolation valve and from the subrepression chamber outlet isolation valve to the inlet of the cylinder. 30
3 shows the LPCB pump discharge pipe up to the injection valve, 31 the reactor injection pipe, 32 the test pipe, and 33 the LPC8 water seal pump.

This low-pressure core spray system is also installed as part of the emergency core cooling system, and includes one pump, piping, and valves.

Consists of support, etc. In this system, suppression pool water is pressurized by the LPCS pump 27 and injected into the shroud of the reactor pressure vessel 1, so that in the event of a loss of coolant accident, the reactor core can be spray cooled and re-flooded. Then, during normal operation, a test pipe 32 is installed that branches off from the LPCS pump discharge pipe 30 and returns the entire system capacity to the subreduction chamber 3, so that a functional test can be performed without injecting water into the reactor. It is now possible to perform valve operation tests required for In addition, a throttle valve and a pressure reducing orifice are installed in the test pipe 32 so that injection pressure can be simulated during testing. - Figure 5 shows a conventional boric acid water injection system (8LC), and the same parts as in Figures 2, 3 and 4 are given the same reference numerals. 34 is a sodium pentaphosphate aqueous solution (hereinafter referred to as oxalic acid water) storage tank, 35 is a boric acid water injection system (SLC) pump, 36 is an SLC test tank, 37
is the injection pump suction pipe, 38 is the blast release valve, 39 is the pump discharge pipe to the blast release valve 38, and 40 is the blast release valve 3.
8 is the injection pipe to the multi-reactor pressure vessel 1, 41 is the SLC
Test tank 36 population stop valve, DSLC test tank 36 population piping, 42 shows the piping from 8LC test tank 36 to the outlet valve, 43 shows the water storage tank 34 to the outlet stop valve. There is.

This boric acid water injection system is installed so that boric acid water can be injected into the reactor in order to maintain the reactor in a cold subcritical state when control rods cannot be inserted during normal operation. It consists of a watering storage tank, a test tank, a crawling watering injection pump, piping, valves, supports, etc. An injection nozzle was installed at the bottom of the core support plate so that boron and reactor water could be mixed uniformly and the reactivity of the reactor core could be effectively controlled.
Hydrolic acid water can be injected into the furnace using an 8LC pump 35. In order to have redundancy with the control rod drive water system as a reactor shutdown system and to increase the reliability of the system, all dynamic equipment (instrumentation, control equipment, etc.) necessary to achieve system functions are duplicated. The emergency AC power supply connected to the
are separated and connected.

Therefore, conventional nuclear reactors equipped with a residual heat removal system, a high-pressure core spray system, a low-pressure core spray system, and a boric acid water injection system, as shown in FIGS. 2, 3, 4, and 5, In the reactor cooling system equipment, the residual heat removal system, which is the reactor emergency shutdown system, the high-pressure core spray system, and the low-pressure core spray system, etc. need to be operated while ensuring the independence of each system. Since each system is installed independently and has its own test piping, the length of piping increases significantly, which increases the amount of piping.

There were disadvantages such as an increase in the amount of piping support, an increase in the amount of piping insulation, and an increase in the number of valve members.

In addition, crud generated from the inner surfaces of the piping and vessels is left to accumulate in the reactor pressure vessel, and as the plant continues to operate, activated crud accumulates at the bottom of the reactor pressure vessel and becomes unstable. There was a drawback that workers could be exposed to radiation when replacing control rods during inspections and during maintenance and inspection of piping, valves, supports, etc. inside the reactor containment vessel.

[Purpose of the invention]

The primary purpose of the present invention is to provide a rational residual heat removal system that eliminates the problems of the prior art, improves the reliability of the reactor containment vessel, and secures effective space.
A second objective is to provide a residual heat removal system that can reduce radiation exposure.

[Summary of the invention]

The present invention provides a nuclear reactor cooling system equipment that has a reactor pressure vessel and a subrection chamber, and is provided with a residual heat removal system, a high pressure core spray system, a low pressure core spray system, and a boric acid water injection system. At least one line between the test piping of the high-pressure core spray system and the heat exchanger exit line of the residual heat removal system, and between the test piping of the low-pressure core spray system and the heat exchanger exit line of the residual heat removal system. (10) characterized in that the points are connected via valves, and further, there is a connection between the heat exchanger outlet line of the residual heat removal system and the downstream side of the blast release valve of the boric acid water injection system. The second feature is that they are connected via a valve.

That is, for example, between the test piping of the high-pressure core spray system and the heat exchanger outlet line of the residual heat removal system (connecting the test piping of the residual heat removal system and the test piping of the high-pressure core spray system and the low-pressure core spray system, By installing remote control valves and providing isolation signals to maintain the independence of each system, it is possible to test the system function [and achieve a rational system configuration, which reduces radiation exposure during maintenance inspections and inspection work within the plant. It is possible to contribute to improving the reliability of the reactor containment vessel, improving economic efficiency by rationalizing equipment, and improving the space and layout around the reactor containment vessel.

Also, for example, between the test piping of the high pressure core spray system and the heat exchanger outlet line of the residual heat removal system, between the test piping of the low pressure core spray system and the heat exchanger exit line of the residual heat removal system, and between the test piping of the low pressure core spray system and the heat exchanger exit line of the residual heat removal system, If the heat exchanger outlet line of the heat removal system and the downstream side of the blast release valve of the boric acid water injection system are connected via valves, the boric acid water injection line connected to the bottom of the reactor pressure vessel High-velocity pure water is injected through the nozzle, and the accumulated crud at the bottom of the reactor pressure vessel is blown away with a jet flow, allowing the normal reactor cooling system equipment to work effectively to cool the reactor pressure vessel and the components connected to it. It is possible to improve the water purification inside the pipes.

In this way, by rationally configuring the residual heat removal system and at the same time effectively flushing the cladding at the bottom of the reactor pressure vessel, it is possible to eliminate the penetration of the reactor pressure vessel subreduction chamber and the residual heat removal system. Heat removal system test piping, valves, and insulation.

Improve the reliability of the reactor containment vessel by reducing the number of supports, etc., secure effective space by improving the arrangement around the outside of the reactor containment vessel, reduce radiation exposure after reactor shutdown by removing crud, and reduce the amount of residual radiation in a rational manner. This makes it possible to provide heat removal system equipment.

[Embodiments of the invention]

FIG. 1 is a system diagram of the overall system configuration of one embodiment, and the same parts as in FIGS. 2 to 5 are given the same reference numerals.

4a, 5a, and 10a are the RHR, heat exchanger, RIHR, pump, and pump discharge piping provided on the HFO2 side, respectively; 4b, 5b, and 10b are the RHR heat exchanger and 几HR pump provided on the LP01 side, respectively. , pump discharge piping, 44 is a valve provided in the piping connecting between the test piping 32 and the pump discharge piping 10b, 45 is a connection between the test piping C (subreduction chamber side) 26 and the pump discharge piping 10a. A valve installed in the piping, 4
6 is a valve provided on the subrepression chamber 26 side of the test pipe (subrepression chamber side) 26; 47;
Reference numeral 48 indicates an explosion release valve provided in the boric acid water injection system; 48 indicates a valve provided in a pipe connecting between the pump discharge pipe 10a and the downstream side of the explosion release valve 47 of the #1 boric acid water injection system; Reference numeral 49 indicates a reactor coolant recirculation system (PLR) piping, and the thick line portion in the figure indicates the system configuration improved by the present invention.

That is, the pump discharge piping 10 of the R, HR heat exchanger 4b
a and the test pipe 32 of the low-pressure core spray system and the valve 44, and the pump discharge pipe 10b of the other R, HR heat exchanger 4b and the test pipe 2 of the high-pressure core spray system.
6 and a pipe connecting the injection pipe 40 of the water injection system.

In addition, the test piping (sub'reaction chamber side) 26 of the HPCS pump 20 and the injection piping 4 of the boric acid water injection system
Piping connecting 0 and valves 45 and 4 attached to it
When valve 48 is open, the system is interlocked so that valve 45 also opens according to the operation signal, and the boric acid water injection system operates properly. In order to do so, when the blast release valve 47 is open, an interlock is formed so that the valve 48 is reliably closed in response to the activation signal, and when the valve 48 is open, the valve 48 is closed. Upon receiving the open signal, the explosion release valve 47 forms an interlock to close.

The valves 45, 48 and the blast release valve 47 are interlocked as follows, and their opening and closing operations can be controlled remotely.

That is, when the valve 48 is opened for the first time, the valve 45 is then opened.
is also interlocked so that it opens upon receiving the open signal. Further, when the blast release valve 47 and the valve 48 are opened, the valve 48 is interlocked so as to be closed upon receiving the opening signal. Further, the explosion release valve 47 is interlocked so that it is closed when the valve 48 is open. Further, when the valve 45 is opened for the first time, the valve 48 is interlocked to be closed.

In this example, when the plant is stopped, HPCS pump 2
0 is activated, valve 46 is pre-closed, and valve 45.48 is activated.
The reactor pressure vessel 1 is supplied with pure water from the condensate storage tank 19 through the injection pipe 40 of the boric acid water injection system.
Inject high-speed water with a flow rate of about 50 m/s or more into the bottom of the tank. Thereby, the accumulated crud at the bottom of the reactor pressure vessel 1 can be thrown up by a jet flow, forced to circulate through the PLR piping 49, and purified by the reactor coolant purification system. 'In order to ensure that the boric acid water injection system operates properly, the valve 48 should be closed when the explosion release valve 47 is open, and when the valve 48 is open during flushing, the explosion should be stopped at the open signal. If an interlock is provided so that the open valve 47 is closed, flushing can be performed without affecting the boric acid water injection system when the plant is stopped. Father, flushing is not normally carried out during plant operation, but even if there is a malfunction in valve opening/closing, pump startup, or activation of the high-pressure core spray system, the valves are interlocked, so the boric acid water There is no problem because the functional integrity of the injection system is sufficiently ensured.

In addition, when carrying out a startup test of the residual heat removal system while the plant is operating or stopped, the valve 45 is opened, the RIHR pump 5a is started, and the water in the subreduction chamber 3 is discharged from the pump discharge pipe 10a. through valve 45
is returned to the subrepression chamber 3 via the test pipe 26. At that time, the valve 45 is open and the J-
6 is interlocked so that the valve 48 is closed upon receiving the 181 signal. Therefore, a start-up test of the residual heat removal system can be sufficiently carried out, and it is possible to prevent water from being accidentally injected into the pressure vessel due to erroneous operation of the valve 48.

In addition, when performing a start-up test of the high-pressure core spray system, the pump 20 is started with the valve 45 closed, and the water in the subreduction chamber 3 (via the PCS pump discharge pipe 23 and the test pipe 26) is started. Then, it can be returned to the subrepression chamber 3 and a startup test can be performed.

Similarly, when performing a start-up test of the low-pressure core spray system, the LPOS pump 27 is started while the valve 44 is closed, and the water in the subrepression chamber 3 is pumped through the LPCS pump pipe 30 to the test pipe. 32, it can be returned to the subrepression chamber 3 and a start-up test can be carried out.

As described above, it is possible to ensure the integrity and independence of the residual heat removal system, spray water system, high pressure core spray system, and low pressure core spray system, and also to prevent the accumulation of crud at the bottom of the reactor pressure vessel. Performing start-up tests of the flushing and residual heat removal systems will not have any adverse effect on the integrity and reliability of each system function.

In addition, according to this reactor cooling system equipment, it is possible to create a system configuration in which the reactor containment vessel and the subrection chamber (approximately 8 to 10 inches in diameter) are shared. The number of personnel is reduced, and the space around the penetration area, which is originally narrow, is improved, making it possible to contribute to the ease of passage for workers, ease of maintenance and inspection work, and the reduction of radiation exposure based on this.

At the same time, the penetration of the reactor containment vessel is reduced, which improves reliability against leakage from penetration welds.
This makes it possible to realize a rationalized and economical reactor containment vessel.

In addition, this reactor cooling system equipment makes it possible to effectively inject high-speed pure water into the reactor pressure vessel to remove and clean accumulated crud inside the reactor in a short period of time.
It prevents increases in the dose rate around the reactor pressure vessel and the piping connected to the reactor pressure vessel, and has the effect of reducing radiation exposure for workers during maintenance, inspection, disassembly, and inspection work in the vicinity.

Furthermore, it is possible to significantly reduce the length of the test piping of the residual heat removal system piping, and it is also possible to significantly reduce the amount of piping, the amount of piping ports, the amount of piping insulation, and the number of valve members. This has the effect of making it possible to realize an economical plan for installing a rational system configuration.

〔Effect of the invention〕

The present invention makes it possible to provide a rational residual heat removal system that can improve the reliability of a reactor containment vessel, secure effective space, and further reduce radiation exposure. And it has great industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an embodiment of the reactor cooling system equipment of the present invention, Fig. 2 is a system diagram of a residual heat removal system of a conventional reactor cooling system, and Fig. 3 is a system diagram of a high-pressure core spray system. 4 is a system diagram of the low-pressure core spray system, and FIG. 5 is a system diagram of the boric acid water injection system. 1... Reactor pressure vessel, 2... Reactor containment vessel, 3
...Subrection chain/<, 4a, 4b...R
, HRI exchanger, 5a, 5b-... 几HR pump, 10
a. 10b...Pump discharge piping, 19...C8T, 20
...HPC8 pump, 21...HPC8 pump suction pipe, 26...test pipe C subrection chamber side), 27...LPOS pump, 30...LPC8 pump discharge pipe (up to injection valve), 32...Test piping, 34...Crawling water storage tank, 35...8LC
Pump, 45. 46... Valve, 47... Blast release valve (provided in the boric acid water injection system), 4B... Valve, 49
...PLR piping.

Claims (1)

[Claims] 1. A reactor cooling system that has a reactor pressure vessel and a subreduction chamber, and is provided with a residual heat removal system, a high-pressure core spray system, a low-pressure core spray system, and a boric acid water injection system. In the equipment, between the test piping of the high-pressure core spray system and the heat exchanger exit line of the residual heat removal system, and between the test piping of the low-pressure core spray system and the heat exchanger exit line of the residual heat removal system. Nuclear reactor cooling system equipment characterized in that at least one point between the two is connected via a valve. 2. In a reactor cooling system facility that has a reactor pressure vessel and a subrepression chamber and is provided with a residual heat removal system, a high pressure core spray system, a low pressure core spray system, and a boric acid water injection system, the high pressure core at least one location between the test piping of the spray system and the heat exchanger exit line of the residual heat removal system, and between the test piping of the low pressure core spray system and the heat exchanger exit line of the residual heat removal system;
The reactor cooling system equipment is characterized in that the heat exchanger outlet line of the residual heat removal system and the downstream side of the blast release valve of the boric acid water injection system are connected via a valve. 3. The blast release valve and the valves provided between the heat exchanger outlet line of the residual heat removal system and the downstream side of the blast release valve of the boric acid water injection system are configured such that their opening and closing states are opposite to each other. A valve interlocked and provided between the blast release valve downstream of the boric acid water injection system and a test pipe of the high pressure core spray system and a heat exchanger outlet line of the residual heat removal system. 3. The reactor cooling system equipment according to claim 2, wherein the valves are interlocked so that their opening and closing states are opposite to each other.