CN113860415A - Nuclear power plant emergency water supply tank deoxygenation method, water supply system and catalytic deoxygenation device - Google Patents

Nuclear power plant emergency water supply tank deoxygenation method, water supply system and catalytic deoxygenation device Download PDF

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CN113860415A
CN113860415A CN202111126291.5A CN202111126291A CN113860415A CN 113860415 A CN113860415 A CN 113860415A CN 202111126291 A CN202111126291 A CN 202111126291A CN 113860415 A CN113860415 A CN 113860415A
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water
catalytic
value
isolation valve
water inlet
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CN113860415B (en
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张永祥
蔡亚清
孟涌
张建华
钱伟程
杨传沿
赖汉鹏
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Cgn Lufeng Nuclear Power Co ltd
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/20Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21DNUCLEAR POWER PLANT
    • G21D1/00Details of nuclear power plant
    • G21D1/02Arrangements of auxiliary equipment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08Seawater, e.g. for desalination
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00Energy generation of nuclear origin

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Abstract

The invention discloses a nuclear power plant emergency water supply tank deoxidizing method, an emergency water supply system and a catalytic deoxidizing device, wherein the catalytic deoxidizing device comprises a water inlet isolation valve, a water supply pump, a hydrogen-oxygen mixer, a catalytic deoxidizing resin bed and a water outlet isolation valve, and a water inlet of the water inlet isolation valve and a water outlet of the water outlet isolation valve are connected with an external water tank body; the catalytic deoxygenation device comprises a first control module, a second control module and a third control module, wherein the first control module is used for measuring the oxygen content value of the water tank body and comparing the oxygen content value with a preset oxygen content threshold value to obtain a first opening value for controlling the water inlet/outlet isolating valve assembly and the water feeding pump; the water inlet and outlet isolating valve component comprises a water inlet isolating valve and a water outlet isolating valve. The invention relates to a nuclear power plant emergency water supply tank deoxygenation method, a water supply system and a catalytic deoxygenation device.

Description

Nuclear power plant emergency water supply tank deoxygenation method, water supply system and catalytic deoxygenation device
Technical Field
The invention relates to the field of nuclear power plants, in particular to a nuclear power plant emergency water supply tank deoxygenation method, a water supply system and a catalytic deoxygenation device.
Background
In recent years, the nuclear power industry in China is rapidly developed. By using 'Hualongyi' construction and CAP1400 successful research and development as marks, China becomes another country with independent autonomous third-generation nuclear power technology and whole industrial chain after the nuclear power strong countries such as the United states, France, Russia and the like.
Hua longyi nuclear power generating set is the third generation nuclear power generating set, and when normal water supply systems such as main water supply flow control system (ARE) and start-up and shut-down water supply system (AAD) ARE unavailable, emergency water supply system (ASG) provides emergency water supply for steam generator so as to satisfy the functional requirement that Steam Generator (SG) continuously discharges waste heat. The waste heat from the reactor coolant system (RCP) generates steam in the steam generator that is vented through a turbine bypass vent system (GCT-c) (if available) or a steam atmospheric vent system (VDA).
The emergency water supply system has the following functions:
in the event of a main steam line rupture (MSLB) event, excessive feedwater injection into the steam generator resulting in core overcooling is prevented by isolating the emergency water injection lines (ASG system tubes) of the affected steam generators.
The ASG system must ensure that emergency feedwater is provided to intact steam generators during expected operating events (DBC-2), rare events (DBC-3), extreme events (DBC-4), core decay and sensible heat of the reactor coolant system (RCP) system is conducted out through the steam generators and continues until the safety injection system (RIS) operates in a waste heat rejection mode (RHR).
In the event of a complex sequence accident (DEC-a), such as a plant blackout (SBO) or complete loss of cold chain (TLOCC), the ASG system provides emergency feedwater to the steam generators, through which the core decay heat and sensible heat of the RCP system are conducted away, bringing the plant to a final state.
Under the accident conditions of primary and secondary side communication such as steam generator heat transfer pipe rupture (SGTR), the emergency water injection pipeline (ASG system pipeline) of the affected steam generator is isolated, and the radioactive substances are prevented from being uncontrollably released to the environment, so that the radioactive substances are contained.
Under the working condition of a water supply pipe rupture (FLB) or MSLB accident occurring in the containment, an emergency water injection pipeline (ASG system pipe) of an affected steam generator is isolated, the flow of high-temperature and high-pressure fluid sprayed into the containment through a crevasse is reduced, and the failure of the integrity of a third barrier caused by the continuous rise of the pressure and the temperature of the containment is prevented.
During normal shutdown of the power plant, the steam generator is filled with water, and chemical agents provided by a chemical dosing System (SIH) of the nuclear island are simultaneously injected into the steam generator to complete the wet maintenance operation.
During normal plant startup, the steam generator is initially filled with water. Before the average temperature of the primary circuit reaches 80 ℃, necessary water replenishing is carried out on the steam generator, and the normal water level is maintained. During the filling period, the SIH system provides chemical agents to ensure that the feed water meets the water quality requirement of the steam generator.
As shown in fig. 1, the ASG system consists of three independent trains of emergency feedwater pumps. Each ASG emergency feed pump train comprises the following equipment:
a concrete water tank;
an emergency feed pump;
a steam generator level regulating valve;
an out-of-containment electrically-actuated isolation valve;
associated valves and piping.
The ASG water tank has the following main technical characteristics:
concrete structure, rectangular parallelepiped, stainless steel lining of the inner surface, inner bottom area 77.5m2Net height 8.94 m;
minimum effective water volume 516.2m3To meet the safety requirement of 24 hours of thermal shutdown; alarming when the liquid level is lower than 2;
water temperature 10-50 deg.C (accident 24 hours, 10-60 deg.C);
normally filled alkaline demineralized water distribution System (SER) demineralized water, emergency water supply from secondary side passive waste heat removal system (ASP), mobile water source as backup;
the device is arranged at the floor height of-4.9 m of a safe factory building, and the top of the device is communicated with the atmosphere;
an independent mixing stirring pump and a pipeline are arranged;
the water in the water tank is oxygen-containing desalted water, SER oxygen-containing water is used for supplementing water or filling water, and nitrogen is not used for covering. A nuclear island chemical dosing System (SIH) dosing line is downstream of the ASG pump outlet level regulating valve, only effective when flooding the Steam Generator (SG).
The design that water that hualong No. one ASG water tank stored is for containing oxygen water has led to many security problems and unit availability influence. The following is a description of specific problems.
1. The safety problem is as follows:
corrosion of structural materials of the secondary side of the steam generator, feed water and leakage of the condenser are main sources of impurities on the secondary side. If these impurities are not removed by the condensate polishing system or the steam generator sewage system, they will be concentrated in the steam generator and form dirt, which leads to corrosion of the heat transfer tubes of the steam generator, decrease of the heat transfer efficiency and decrease of the main steam pressure.
Table 1 shows the requirements of hualong No. one chemical specification and preliminary safety analysis report on SG water quality.
Figure BDA0003277759040000041
Description of the drawings:
pH, NH when starting from a hot standby4 +、O2The Fe value may be higher.
ADG (feedwater deaerator system) monitoring as AHP backup monitoring point.
TABLE 1 steam generator Normal feedwater chemistry Specification requirements
According to the analysis, the oxygen-containing water in the Hualong I ASG water tank is injected into the SG steam generator, the water quality of the SG can be influenced, the service life of the SG is further influenced, and even the heat transfer pipe of the steam generator is leaked, so that the integrity of the steam generator is influenced. Hualong number one the following two conditions can cause oxygen-containing water in ASG tanks to enter the SG:
(1) when normal water supply is lost under the accident condition, the SG is low in liquid level by 2, and the loss of an external electric field (LOOP) signal and a safe injection signal simultaneously occurs to start ASG auxiliary water supply. Because the ASG water tank contains oxygen water, the accident water supply corrodes SG, influences steam generator's integrality and life-span.
(2) The Hualongyi ASG system runs a periodic test, and has influence on SG water quality: during the tests such as the full flow test of the ASG pump (executed once per fuel cycle), the cavitation margin test of the ASG system (executed once every two fuel cycles), the mechanical limit test of the ASG power limiting valve (executed once every 10 fuel cycles), and the like, the water in the ASG water tank is actually injected into the steam generator.
Under the condition of a seawater leakage accident of the condenser, the chemical technical specification and the operation program of the second generation unit require, a corresponding circulating water system (CRF) pump is shut down, the power is reduced to thermal shutdown as soon as possible, the water supply of a steam generator is switched to ASG when the Pn is less than 2%, and ARE water supply is directly replaced. And Hualongyi will be unable to use ASG deoxidization water to supply water for SG because of the water tank oxygen water containing design of ASG, and the unit can't stop in mode 1 or mode 2, need withdraw to safe injection system (RIS) with the mode 4 of waste heat removal mode (RHR) operation, has increased SG quality of water deterioration time and unit and has overhauld the time limit for a project.
Because the maintenance of the conventional island in the daily period of the unit, which relates to the vacuum damage of the condenser, needs a primary circuit matched with a mode 4 that a safety injection system (RIS) operates in a waste heat discharge mode (RHR), the maintenance is not like a second-generation nuclear power unit which only needs to be withdrawn to a thermal shutdown or a thermal standby state. Hualongyi unit has increased withdrawal operation risk and mode conversion risk, has also increased the risk that human error and equipment impact damage.
Under the conditions of temporary shutdown, important fault overhaul and overhaul of a conventional island and the like, the unit can be transited between power operation and the operation of a safety injection system in a residual heat removal mode (RIS/RHR) for multiple times in one fuel cycle, the frequency of the use of an isolation valve between the RIS and the RCP is greatly increased compared with that of a second-generation nuclear power unit, the frequency of valve faults can also be increased, and further the safety influence is brought.
2. The unit availability factor influences:
the design of oxygen-containing water supply for the Hualong I ASG water tank can affect the overhaul period and the unplanned shutdown maintenance period.
A. The actual construction period of overhaul is prolonged
In the starting and stopping stage, because the ASG water tank contains oxygen water, the unit can not use the ASG to cool the primary loop when moving downwards, and the heat of a steam generator is brought out by the running of a bypass discharge system (GCT-c) and a main water supply system (ARE) of a steam turbine until the temperature of the primary loop reaches 120 ℃ and the waste heat discharge mode (RIS/RHR) of a safe injection system is connected; when the system goes upwards, the system leaves the RIS/RHR mode before 120 ℃, namely a bypass discharge system (GCT-c) of a steam turbine and an ARE ARE needed to operate a cooling loop, so that the work of two-loop preparation, flushing and the like which ARE originally parallel to the heating and the pressure rise of the loop to reach the critical state ARE changed into serial work. The two-loop water supply loop and the steam loop are stopped late and recovered early, the two-loop overhaul and the primary loop overhaul cannot be carried out simultaneously on the whole, the available time for the two-loop overhaul is very short, the two-loop overhaul becomes a key path, and the actual overhaul period is prolonged. And the CPR1000 unit descends until the water supply of the steam generator is switched from ARE to ASG when the thermal power of the reactor is less than 2 percent Pn, and an atmospheric emission system (GCT-a) is adopted to cool the primary loop, at the moment, the main steam isolation valve can be closed, so that the primary loop and the secondary loop ARE separated, and the shutdown and the maintenance of the secondary loop ARE started. Similarly, when CPR1000 is up, the steam generator feed is fed by ASG before reactor thermal power 2% Pn, and atmospheric vent system (GCT-a) is used to cool the primary loop without the need for a two loop operation.
Figure BDA0003277759040000061
TABLE 2 calculation of project duration for Hualong I major repair conventional island
Since there are no multiple overhaul instances for the hualong one-unit, as shown in table 2, the conventional island construction period of the unit plus about 5 days (two loops cooperate with one loop to cause a delay in downlink and an uplink advance time) is taken as the hualong one-unit conventional island overhaul period by calculating the data of nearly 9 overhauls of a certain CPR1000 unit. The calculation result shows that all the conventional islands after 8 times of overhaul become critical paths, the actual construction period is exceeded, the overhaul construction period is prolonged by 2-5 days in different degrees, and huge economic loss is caused.
B. Impact on daily unplanned overhauls:
daily routine island defects need to be repaired, and the CPR1000 nuclear island only needs to be withdrawn to a hot standby state or a hot shutdown state. However, the Hualongyi unit needs to be withdrawn to a mode 4 that a safety injection system (RIS) runs in a waste heat removal mode (RHR), and the withdrawal is deeper; such as the following day-to-day service work:
Figure BDA0003277759040000071
the working of a steam turbine generator set shafting, the disassembly and maintenance of a steam turbine bypass discharge system (GCT-c) and the like require a condenser to break vacuum, stop a vehicle and the like;
Figure BDA0003277759040000072
two-loop water side related defects: the main water supply isolation valve can not be closed, the leakage or the fault of a main water supply system (ARE) pipeline test pore plate or a Venturi tube, the small leakage of a condensate pump inlet or outlet main pipe, the leakage of a deaerator body steam side pipeline and the like can not cause the immediate loss of the two-loop water supply but can not be isolated, so that the efficiency of a unit is reduced and great industrial safety risk is caused;
Figure BDA0003277759040000073
the two pumps are stopped completely due to the problems of failure of the circulating water pump or high pressure difference of a drum network caused by open sea factors.
C. Influence on daily planned outages
At present, the participation of a nuclear power unit in power grid peak regulation becomes a frequent phenomenon, the nuclear power unit is stopped for many times according to the requirement of a power grid every year, the unit can stop in an NS/SG mode due to the cooperation of the Hualong No. I ARE + GCT-c, but the NS/SG is only a transition mode and an unstable operation mode in the design of Hualong; under the working condition, the APA pump is always in a low-flow operation working condition, and the reliability of the APA pump and the deaerator is influenced at the moment; therefore, in a general temporary shutdown condition, the unit is required to be switched to the mode 4 in which the safety injection system (RIS) operates in the waste heat removal mode (RHR), which results in that the time for operating the first hualong unit is longer than that for operating the CPR1000 in the start-stop stage, such that the associated operation time for cooling down, heating up and boosting is increased, and corresponding economic loss is caused.
Disclosure of Invention
The invention aims to solve the technical problem of providing an improved deoxidizing method for an emergency water supply tank of a nuclear power plant, an emergency water supply system and a catalytic deoxidizing device aiming at the defects.
The technical scheme adopted by the invention for solving the technical problems is as follows: the catalytic deoxygenation device comprises a water inlet isolation valve, a water feed pump, a hydrogen-oxygen mixer, a catalytic deoxygenation resin bed and a water outlet isolation valve which are sequentially connected, wherein a water inlet of the water inlet isolation valve and a water outlet of the water outlet isolation valve are respectively connected with an external water tank body;
the catalytic deoxygenation device further comprises a first control module, wherein the first control module is used for measuring an oxygen content value of the water tank body and comparing the oxygen content value with a preset oxygen content threshold value to obtain a first opening value for controlling the water inlet and outlet isolation valve assembly and the water feeding pump; the water inlet and outlet isolation valve component comprises the water inlet isolation valve and the water outlet isolation valve.
Preferably, the catalytic oxygen removal device further comprises a second control module, wherein the second control module is used for measuring a liquid level value of the water tank body and comparing the liquid level value with a preset liquid level threshold value to obtain a second opening value for controlling the water inlet and outlet isolation valve assembly and the water feeding pump.
Preferably, the catalytic oxygen removal device further comprises a third control module, wherein the third control module is used for receiving the first opening value and the second opening value and comparing the first opening value with the second opening value to obtain a third opening value for controlling the water inlet and outlet isolation valve assembly and the water feed pump.
Preferably, catalytic oxygen removal device still includes degasification tower and degasification fan, degasification fan be used for to the degasification tower blows in gas, the degasification tower with catalytic oxygen removal resin bed is connected, just the degasification tower is used for with hydrogen in the catalytic oxygen removal resin bed discharges.
Preferably, the catalytic deoxygenation device further comprises a resin trap disposed between the catalytic deoxygenation resin bed and the water outlet isolation valve, the resin trap being configured to capture resin.
The nuclear power plant emergency water supply tank deoxidizing method comprises the following steps:
s1, measuring an oxygen content value of a tank body of a water tank;
s2, judging whether the oxygen content value exceeds a preset first oxygen content threshold value, if so, executing a step S3; if not, the current situation is kept;
s3, outputting a first opening signal, and opening a water inlet and outlet isolation valve assembly of the catalytic deoxygenation device and the water feed pump according to the first opening signal;
s4, judging whether the oxygen content value is lower than a preset second oxygen content threshold value or not, and if so, outputting a first closing signal; if not, the current situation is kept; the water inlet and outlet isolating valve assembly and the water feeding pump are closed according to the first closing signal;
wherein the first opening value comprises the first on signal and the first off signal.
Preferably, the nuclear power plant emergency feedwater tank oxygen removal method further comprises the following steps:
s5, measuring the liquid level value of the water tank body,
s6, judging whether the liquid level value is lower than a preset liquid level threshold value or not, if so, executing a step S7; if not, go to step S8;
s7, outputting a second closing signal, and closing the water inlet and outlet isolating valve assembly and the water feeding pump according to the second closing signal;
s8, keeping the current situation;
wherein the second opening value comprises the second off signal.
Preferably, the nuclear power plant emergency feedwater tank oxygen removal method further comprises the following steps:
s9, receiving the first opening degree value and the second opening degree value;
s10, judging whether the first opening value is a first opening signal and the second opening value is a second closing signal, if so, executing a step S11;
s11, outputting a third opening value, wherein the third opening value comprises a third closing signal, and the water inlet and outlet isolating valve assembly and the water feeding pump are closed according to the third closing signal.
The emergency water supply system of the nuclear power plant comprises a water tank assembly and the catalytic deoxygenation device;
the water tank assembly comprises a water tank body, and an oxygen analyzer and a liquid level meter which are respectively connected with the water tank body; the catalytic deoxygenator device is connected with the water tank component.
Preferably, the water tank assembly further comprises a nitrogen supply isolation valve and a nitrogen pressure regulating valve which are respectively connected with the water tank body, the nitrogen supply isolation valve is used for accessing nitrogen, and the nitrogen pressure regulating valve is used for regulating nitrogen pressure.
The beneficial effects of the implementation of the invention are as follows: according to the nuclear power plant emergency water supply tank deoxygenation method, the emergency water supply system and the catalytic deoxygenation device, the oxygen content value of the tank body of the water tank is measured, and the first opening value is output according to the oxygen content value, so that the opening and closing conditions of the water inlet and outlet isolation valve assembly and the water supply pump are controlled, and the automatic control of catalytic deoxygenation on the water tank of the emergency water supply system is realized.
The invention discloses a nuclear power plant emergency water supply tank deoxygenation method, an emergency water supply system and a catalytic deoxygenation device, and relates to a Hualongyi nuclear power unit (third generation nuclear power unit) emergency water supply system (ASG) water tank deoxygenation method.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic diagram of a nuclear power plant emergency feedwater system according to the prior art;
FIG. 2 is a schematic diagram of a nuclear power plant emergency feedwater system in accordance with certain embodiments of the present invention;
FIG. 3 is a schematic representation of a catalytic deoxygenator device in accordance with some embodiments of the present invention;
FIG. 4 is a flow chart of a method for deoxidizing an emergency feedwater tank of a nuclear power plant in accordance with certain embodiments of the present invention;
FIG. 5 is a flow chart of a method for deoxidizing an emergency feedwater tank of a nuclear power plant in accordance with further embodiments of the present invention;
FIG. 6 is a flow chart of a method for deoxidizing an emergency feedwater tank of a nuclear power plant in accordance with certain preferred embodiments of the present invention.
Detailed Description
For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
Fig. 2 shows an emergency water supply system of a nuclear power plant in some embodiments of the present invention, which is used for chemically catalyzing and deoxidizing ASG water tanks through a catalytic deoxidizing device 10, so as to ensure that the stored water in the ASG water tanks is deoxidized water, thereby eliminating or reducing the influence of defects in the prior art on the safety and the availability of units. The emergency water supply system for the nuclear power plant comprises a water tank assembly 20 and a catalytic deoxygenation device 10, wherein the catalytic deoxygenation device 10 is connected with the water tank assembly 20.
The water tank assembly 20 includes a water tank body 21, and an oxygen analyzer 22 and a liquid level meter 23 respectively connected to the water tank body 21. The oxygen analyzer 22 is used for measuring the oxygen content value in the water tank body 21, and the liquid level meter 23 is used for measuring the liquid level value.
In some preferred embodiments, the water tank assembly 20 further comprises a nitrogen supply isolation valve 25 and a nitrogen pressure regulating valve 26 respectively connected to the water tank body 21, wherein the nitrogen supply isolation valve 25 is used for introducing nitrogen, and the nitrogen pressure regulating valve 26 is used for regulating the nitrogen pressure. The advantage of setting up nitrogen gas supply isolation valve 25 and nitrogen gas pressure regulating valve 26 is that, water tank box 21 adopts the mode of nitrogen gas cover, and reducible or prevent that oxygen from getting into water tank box 21 and leading to the deoxidization water oxygen content in water tank box 21 to rise, simultaneously, sets up water tank nitrogen gas pressure regulating valve 26, guarantees that water tank box 21 pressure is the pressure of pressure a little. The nitrogen pressure regulating valve 26 exhausts to the outside of the factory building, so that nitrogen is prevented from being accumulated in the factory building, and industrial safety risks are avoided.
Referring to fig. 2 and 3, the catalytic deoxygenation device includes a water inlet isolation valve, a water feed pump, a hydrogen-oxygen mixer, a catalytic deoxygenation resin bed, a water outlet isolation valve, a degassing tower, a degassing fan, a resin trap, a first control module, a second control module, and a third control module. In the catalytic deoxygenation device, a water feeding pump absorbs water from an outlet pipeline of a water tank body through a water inlet isolation valve, and liquid in the water tank body is deoxygenated through a hydrogen-oxygen mixer and a catalytic deoxygenation resin bed and then returns to the water tank body, so that the dissolved oxygen level is kept within a chemical limit range.
Wherein, the water inlet isolation valve 191, the water feeding pump 11, the oxyhydrogen mixer 12, the catalytic deoxidizing resin bed 13 and the water outlet isolation valve 192 are connected in sequence, and the water inlet of the water inlet isolation valve 191 and the water outlet of the water outlet isolation valve 192 are respectively connected with the external water tank body 21.
The hydrogen-oxygen mixer 12 is a stainless steel in-line static mixer, and the liquid in the tank body 21 is driven by the feed pump 11 into the hydrogen-oxygen mixer 12 to be mixed with the injected hydrogen. The hydrogen gas is injected from the bottom of the hydrogen-oxygen mixer 12 and dissolves in the water while flowing upward through the hydrogen-oxygen mixer 12.
Undissolved hydrogen leaves the hydrogen-oxygen mixer 12 and enters the catalytic oxygen scavenging resin bed 13. After hydrogen is added into a hydrogen-oxygen mixer 12, water enters a catalytic oxygen removal resin bed 13 for catalytic removalThe oxygen resin bed 13 contains an anionic resin as a catalyst for converting an oxygen-hydrogen mixture to water. The hydrogen and oxygen are combined to produce water as a byproduct through catalytic reaction in the catalytic oxygen removal resin bed 13. The equation for the reaction is 2H2+O2=2H2And O. The deoxygenated water flows out of the catalytic deoxygenating resin bed 13 and returns to the tank body 21.
It is understood that the water inlet isolation valve 191, the feed water pump 11, the hydrogen-oxygen mixer 12, the catalytic deoxygenating resin bed 13, and the water outlet isolation valve 192 constitute a catalytic deoxygenation process. The water inlet isolation valve 191 and the water outlet isolation valve 192 are used for water inlet and water outlet respectively, the water supply pump 11 is used for providing power, the hydrogen-oxygen mixer 12 is used for mixing hydrogen, and the catalytic deoxidizing resin bed 13 is used for catalytic deoxidizing. The water inlet isolation valve 191, the water feed pump 11, the hydrogen-oxygen mixer 12, the catalytic oxygen removal resin bed 13 and the water outlet isolation valve 192 constitute the most basic catalytic oxygen removal process.
In some preferred embodiments, the catalytic oxygen removal device 10 further comprises a degassing tower 15 and a degassing fan 151, the degassing fan 151 is used for blowing gas into the degassing tower 15, the degassing tower 15 is connected with the catalytic oxygen removal resin bed 13, and the degassing tower 15 is used for discharging hydrogen in the catalytic oxygen removal resin bed 13. In particular, a continuous discharge line is provided leading to a forced air purged deaeration tower 15, the deaeration tower 15 being discharged to the atmosphere outside the plant. The benefit of the provision of the de-aeration column 15 and de-aeration fan 151 is that any hydrogen build-up in the catalytic deoxygenating resin bed 13 is prevented.
In some preferred embodiments, the catalytic deoxygenator device 10 further includes a resin trap 14 disposed between the catalytic deoxygenation resin bed 13 and the outlet isolation valve 192, the resin trap 14 for trapping resin. Specifically, a resin trap 14 is provided in the outlet line from the catalytic oxygen scavenging resin bed 13. The benefit of providing resin trap 14 is that if there is a malfunction inside the catalytic oxygen scavenging resin bed 13, the resin trap 14 will trap the resin.
In some embodiments, the catalytic deoxygenator device 10 further includes a first control module 16, a second control module 17, and a third control module 18.
The first control module 16 is used for measuring the oxygen content value of the water tank body 21 and comparing the oxygen content value with a preset oxygen content threshold value to obtain a first opening value for controlling the water inlet and outlet isolating valve assembly and the water feeding pump 11; the water inlet and outlet isolation valve component comprises a water inlet isolation valve 191 and a water outlet isolation valve 192. The second control module 17 is used for measuring the liquid level value of the water tank body 21 and comparing the liquid level value with a preset liquid level threshold value to obtain a second opening value for controlling the water inlet and outlet isolating valve assembly and the water feeding pump 11. The third control module 18 is configured to receive the first opening value and the second opening value, and compare the first opening value with the second opening value to obtain a third opening value for controlling the water inlet/outlet isolation valve assembly and the water feed pump 11.
As will be appreciated, the first control module 16 is connected to an oxygen analyzer 22 for measuring the oxygen content of the tank body 21; the second control module 17 is connected with a liquid level meter 23 so as to measure the liquid level value of the water tank body 21; the third control module 18 is connected to the first control module 16 and the second control module 17 to obtain a first opening value and a second opening value. The first control module 16, the second control module 17 and the third control module 18 are connected with the water inlet and outlet isolation valve assembly and the water feed pump 11, so that the first opening value, the second opening value and the third opening value are sent to the water inlet isolation valve 191, the water outlet isolation valve 192 and the water feed pump 11, and the opening and closing states of the water inlet isolation valve 191 and the water outlet isolation valve 192 and the starting and stopping of the water feed pump 11 are controlled.
The benefit of providing the first control module 16, the second control module 17 and the third control module 18 is that the catalytic deoxygenator device 10 can be turned on and off on site, or placed "on the fly". When the unit is switched to a remote control mode on a local control cabinet, the catalytic deoxygenator device 10 can be remotely controlled to receive remote start permission and remote stop permission commands sent by a main control room. The specific mode is as follows:
in the automatic control state, the catalytic deoxygenator device 10 is interlocked with the oxygen analyzer 22 and the level gauge 23 of the tank body 21. If an oxygen content signal of the oxygen analyzer 22 is received, the water inlet isolation valve 191 is automatically opened, the catalytic deoxygenation process is automatically started, and the water outlet isolation valve 192 is also automatically opened; if the signal of low oxygen content is received, the catalytic deoxygenation process is automatically stopped, and the water inlet isolation valve 191 and the water outlet isolation valve 192 are automatically closed; if a low level signal is received from the tank body 21, the catalytic deoxygenation process is automatically stopped and the low level signal is superior to the signal from the oxygen analyzer 22 to ensure that the catalytic deoxygenation device 10 has sufficient net suction head for the water pump 11.
Alternatively, the first control module 16, the second control module 17, and the third control module 18 may or may not be provided. When the first control module 16, the second control module 17 and the third control module 18 are not provided, the water inlet and outlet isolation valve assembly and the feed pump 11 are controlled manually, that is, the water inlet isolation valve 191 and the water outlet isolation valve 192 are manually opened or closed manually, and the feed pump 11 is started or stopped manually.
The specific steps of the method for deoxidizing the emergency feedwater tank of the nuclear power plant according to some embodiments of the present invention will be described with reference to fig. 2-6. The nuclear power plant emergency water supply tank deoxygenation method is used for carrying out chemical catalytic deoxygenation on an ASG water tank through the chemical catalytic deoxygenation device 10, and ensures that stored water in the ASG water tank is deoxygenated water, so that the influence of defects in the prior art on the safety and the availability of a unit is eliminated or reduced.
Referring to fig. 2-4, the method for deoxidizing the emergency feedwater tank of the nuclear power plant in some embodiments includes steps S1-S4:
s1, measuring an oxygen content value of a water tank body 21;
s2, judging whether the oxygen content value exceeds a preset first oxygen content threshold value, if so, executing a step S3; if not, the current situation is kept;
s3, outputting a first opening signal, and opening a water inlet and outlet isolation valve assembly of the catalytic deoxygenation device 10 and a water feeding pump 11 according to the first opening signal;
s4, judging whether the oxygen content value is lower than a preset second oxygen content threshold value or not, and if so, outputting a first closing signal; if not, the current situation is kept; the inlet and outlet water isolation valve assembly and the feed pump 11 are closed in response to the first closing signal.
In steps S1-S4, the first control module 16 measures the oxygen content value of the tank body 21 and compares the oxygen content value with a predetermined oxygen content threshold to obtain a first opening value for controlling the water inlet/outlet isolation valve assembly and the water pump 11. The oxygen content threshold comprises a first oxygen content threshold and a second oxygen content threshold, and the first opening value comprises a first opening signal and a first closing signal. If the oxygen content value exceeds a preset first oxygen content threshold value, outputting a first opening signal to open the water inlet and outlet isolating valve assembly and the water feeding pump 11; if the oxygen content value is lower than the preset second oxygen content threshold value, a first closing signal is output, so that the water inlet and outlet isolating valve assembly and the water feeding pump 11 are closed. The water inlet and outlet isolation valve component comprises a water inlet isolation valve 191 and a water outlet isolation valve 192. In some preferred embodiments, the first oxygen content threshold is 15 μ g/kg or 20 μ g/kg and the second oxygen content threshold is 5 μ g/kg. The oxygen content threshold can be set according to actual requirements, and is not limited here as long as related functions can be realized.
Specifically, if an oxygen content signal of the oxygen analyzer 22 is received, the water inlet isolation valve 191 is automatically opened, the catalytic deoxygenation process is automatically started, and the water feed pump 11 and the water outlet isolation valve 192 are also automatically opened; if the oxygen content is low, the catalytic deoxygenation process is automatically stopped, and the water inlet isolation valve 191, the water feed pump 11 and the water outlet isolation valve 192 are automatically closed.
Referring to fig. 2-5, the method for deoxidizing the emergency feedwater tank of the nuclear power plant in some embodiments further includes steps S5-S8:
s5, measuring the liquid level value of the water tank body 21,
s6, judging whether the liquid level value is lower than a set liquid level threshold value or not, if so, executing a step S7; if not, go to step S8;
s7, outputting a second closing signal, and closing the water inlet and outlet isolating valve assembly and the water feeding pump 11 according to the second closing signal;
s8, keeping the current situation;
wherein the second opening value comprises a second off signal.
In steps S5-S8, the second control module 17 is used for measuring the level value of the tank body 21 and comparing the level value with a preset level threshold value to obtain a second opening value for controlling the water inlet and outlet isolation valve assembly and the feed pump 11. If the liquid level value is lower than the preset liquid level threshold value, outputting a second closing signal to close the water inlet and outlet isolating valve assembly and the water feeding pump 11; and if the liquid level value is not lower than the preset liquid level threshold value, keeping the current situation. Preferably, the liquid level threshold is 0.5 m. The liquid level threshold value can be set according to actual requirements, and is not limited here as long as related functions can be realized.
Referring to fig. 2-6, the method for deoxidizing the emergency feedwater tank of the nuclear power plant in some embodiments further includes steps S9-S11:
s9, receiving a first opening degree value and a second opening degree value;
s10, judging whether the first opening degree value is a first opening signal and the second opening degree value is a second closing signal, if so, executing a step S11;
and S11, outputting a third opening value, wherein the third opening value comprises a third closing signal, and the water inlet and outlet isolating valve assembly and the water feeding pump 11 are closed according to the third closing signal.
In steps S9-S11, the third control module 18 receives the first and second opening values and compares the first and second opening values to obtain a third opening value for controlling the water inlet and outlet isolation valve assembly and the feed pump 11. If the first opening value is a first opening signal and the second opening value is a second closing signal, outputting a third closing signal to close the water inlet and outlet isolating valve assembly and the water feeding pump 11; if the first opening value is not the first opening signal and the second opening value is the second closing signal, the current situation is not output, namely the current situation is kept. The advantage of this arrangement is that the level of the level gauge 23 is superior to the oxygen content value of the oxygen analyzer 22 to ensure sufficient net suction head for the feed pump 11 of the catalytic deoxygenator device 10.
In other embodiments of the present invention, a catalytic oxygen removal device 10 is further provided, which is the same as the catalytic oxygen removal device 10 in the foregoing embodiments, and is not described herein again as long as related functions can be achieved.
In some embodiments of the invention, a catalytic deoxygenation device 10 is arranged for an emergency water supply ASG system water tank of Hua Long I nuclear power unit, and can be used for manually or automatically deoxygenating water in the ASG water tank, so that the oxygen content of the ASG water tank is kept within a limit value. Compare for containing oxygen water with former design ASG water tank, effectively avoided ASG water tank to steam generator water injection under accident condition and experimental condition to lead to steam generator to corrode, avoided steam generator's life-span to shorten. Meanwhile, the ASG can realize the function of cooling the steam generator during normal ascending and descending, thereby greatly improving the flexibility and the availability ratio of the unit.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that several modifications and adaptations to those skilled in the art without departing from the principles of the present invention should also be considered within the scope of the present invention.

Claims (10)

1. The catalytic deoxygenation device is characterized by comprising a water inlet isolation valve (191), a water feed pump (11), a hydrogen-oxygen mixer (12), a catalytic deoxygenation resin bed (13) and a water outlet isolation valve (192) which are sequentially connected, wherein a water inlet of the water inlet isolation valve (191) and a water outlet of the water outlet isolation valve (192) are respectively connected with an external water tank body (21);
the catalytic deoxygenation device (10) further comprises a first control module (16), wherein the first control module (16) is used for measuring an oxygen content value of the water tank body (21) and comparing the oxygen content value with a preset oxygen content threshold value to obtain a first opening value for controlling the water inlet/outlet isolation valve assembly and the feed water pump (11); the water inlet and outlet isolation valve component comprises the water inlet isolation valve (191) and the water outlet isolation valve (192).
2. The catalytic deoxygenator device according to claim 1, wherein the catalytic deoxygenator device (10) further comprises a second control module (17), wherein the second control module (17) is configured to measure a level value of the tank body (21) and compare the level value with a preset level threshold value to obtain a second opening value for controlling the water inlet and outlet isolation valve assembly and the feed pump (11).
3. The catalytic deoxygenator device of claim 2, wherein the catalytic deoxygenator device (10) further comprises a third control module (18), the third control module (18) being configured to receive the first and second opening values and to compare the first and second opening values to obtain a third opening value for controlling the water inlet/outlet isolation valve assembly and the feed water pump (11).
4. The catalytic oxygen removal device of any one of claims 1-3, wherein the catalytic oxygen removal device (10) further comprises a degassing tower (15) and a degassing fan (151), the degassing fan (151) is used for blowing gas into the degassing tower (15), the degassing tower (15) is connected with the catalytic oxygen removal resin bed (13), and the degassing tower (15) is used for discharging hydrogen in the catalytic oxygen removal resin bed (13).
5. The catalytic deoxygenator device according to any one of claims 1-3, wherein the catalytic deoxygenator device (10) further comprises a resin trap (14) arranged between the catalytic deoxygenating resin bed (13) and the outlet water isolation valve (192), the resin trap (14) being configured to trap resin.
6. A nuclear power plant emergency water supply tank deoxygenation method is characterized by comprising the following steps:
s1, measuring the oxygen content value of a water tank body (21);
s2, judging whether the oxygen content value exceeds a preset first oxygen content threshold value, if so, executing a step S3; if not, the current situation is kept;
s3, outputting a first opening signal, and opening a water inlet and outlet isolation valve assembly of the catalytic oxygen removal device (10) and the water feed pump (11) according to the first opening signal;
s4, judging whether the oxygen content value is lower than a preset second oxygen content threshold value or not, and if so, outputting a first closing signal; if not, the current situation is kept; the water inlet and outlet isolating valve component and the water feeding pump (11) are closed according to the first closing signal;
wherein the first opening value comprises the first on signal and the first off signal.
7. The method for deoxidizing the emergency feedwater tank of the nuclear power plant as recited in claim 6, further comprising:
s5, measuring the liquid level value of the water tank body (21),
s6, judging whether the liquid level value is lower than a preset liquid level threshold value or not, if so, executing a step S7; if not, go to step S8;
s7, outputting a second closing signal, and closing the water inlet and outlet isolating valve assembly and the water feeding pump (11) according to the second closing signal;
s8, keeping the current situation;
wherein the second opening value comprises the second off signal.
8. The method for deoxidizing the emergency feedwater tank of the nuclear power plant as recited in claim 7, wherein the method for deoxidizing the emergency feedwater tank of the nuclear power plant further comprises:
s9, receiving the first opening degree value and the second opening degree value;
s10, judging whether the first opening value is a first opening signal and the second opening value is a second closing signal, if so, executing a step S11;
s11, outputting a third opening value, wherein the third opening value comprises a third closing signal, and the water inlet and outlet isolating valve assembly and the water feeding pump (11) are closed according to the third closing signal.
9. An emergency water supply system for a nuclear power plant, comprising a water tank assembly (20) and a catalytic deoxygenator device (10) according to any one of claims 1-5;
the water tank assembly (20) comprises a water tank body (21), and an oxygen analyzer (22) and a liquid level meter (23) which are respectively connected with the water tank body (21); the catalytic oxygen removal device (10) is connected with the water tank assembly (20).
10. The emergency water supply system of a nuclear power plant according to claim 9, wherein the water tank assembly (20) further comprises a nitrogen supply isolation valve (25) and a nitrogen pressure regulating valve (26) respectively connected to the water tank body (21), the nitrogen supply isolation valve (25) being used for introducing nitrogen, and the nitrogen pressure regulating valve (26) being used for regulating nitrogen pressure.
CN202111126291.5A 2021-09-24 2021-09-24 Deoxygenation method, water supply system and catalytic deoxygenation device for emergency water supply tank of nuclear power plant Active CN113860415B (en)

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