JPS62254099A - Controller for quantity of hydrogen injected to 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] [Purpose of R, Light] (Industrial Field of Application) The present invention relates to a hydrogen injection amount control device for a reactor-subsystem in a boiling water reactor (hereinafter referred to as BWR). Regarding.

(Prior Art) A system overview of a conventional sWR-order system and a reactor water sample collection method will be explained with reference to FIG. In the BWR secondary system (15), high-purity water is used as a coolant.The heat generated in the reactor core 1 generates steam, and this steam flows through the main steam pipe 2 to the high-pressure turbine 3, The steam is guided to a low pressure turbine 4 and drives these turbines 3.4.The steam that has done work in the turbine 3.4 is cooled by a condenser 5, condensed and returned to water.This water is fed to a condensate pump 6. , is sent to the reactor water supply system via the condensate purification system 7, is further back-pressured by the water supply pump E, and is injected into the reactor pressure vessel 9.

On the other hand, some or all of the reactor water is recirculated outside the reactor by the reactor recirculation pump 10.

This is to forcibly increase the core flow rate and remove more heat from the core 1.

Furthermore, a portion of this recirculated water is transferred to the reactor coolant purification system 12.
After being purified through the reactor coolant purification system recirculation pump 11 and the reactor coolant purification system 12, the atomic or flood control system C. b) 1-3 Conventional BWR
Plan 1 ~ Smell'' (usually involves collecting samples of reactor water in five steps. -7f) However, the reactor coolant purification system 12 person 11 i,: i, Q (, J
J at the sample collection point. Su1 Tsuku/Shilling Line 13
The reactor water is sample analysis −5 knock 14i, :: guided by 1°. In this case, the reactor water is the source J′: reactor
,! if] Heat exchanged by the shrine purification system heat exchanger 15 7
Is there a decrease after sample collection? L'+, reduced pressure Hi, no need to do 1. The nuclear reactor coolant purification system
diE'JA is a little higher than 4f and the flow velocity is too fast, so the reactor water reaches the sampling point after leaving the pressure vessel 9 -4-
Rumatei,: L↓'It takes a considerable amount of time.

Furthermore, when the reactor cooling VJ purification system is isolated, reactor water is sampled from a sampling point provided at the reactor recirculation system pump flO outlet L-1, and two loaves are placed in the analysis rack 14.

In this case, because the reactor water is high temperature and stagnant, the sample must be placed in the analysis rack's own cooler 16. The temperature and pressure are reduced by the pressure reduction mechanism 17. In the sample analysis rack 14, dissolved oxygen concentration, electrical conductivity, corrosion products, silica concentration, etc. are measured.

Jj, figure center mark 'i-52'''l I, reactor + 8 storage vessel 4 1゜ In this way, in a normal BWR, (1) water is added to the reactor coolant purification system. [1, or) The water quality of the recirculation system of the raw material 1 reactor [] is representative of the water quality of 15%.

C, Corrosion of the metal materials that make up the nuclear reactor 43
From the second point, reactor water melt i'fi'l! Prime i: The most important factor is the luck of BWR (1η, smell). d'3, reactor water supply °30p
1, which is around p+).
Because the line suspension is extremely high, the water resistance line decomposition is difficult 3
, )-b 02 , )-102・・・・・・・・・・・・
. . . A z reaction occurs as shown in (1), and finally 9 chemically stable chemical rods such as f-12,02,1-bo2 are formed. As a result, the level of dissolved F acid in the reactor water is around 200 ppb1, and the temperature of the feed water is high.

) Hydrogen injection technology has recently been developed for the outboard BWR Zorant in order to significantly lower this dissolved oxygen concentration and further ensure the integrity of the material. This is a method that is currently being implemented (1), in which hydrogen is injected from the water supply system to maintain the inside of the 7τ reactor in a reducing H atmosphere, thereby suppressing the generation of oxygen in the reactor core.

Figure 3 shows an example of reducing dissolved wiring in a plant, and Figure 10 shows an example of how to reduce the amount of dissolved wiring in a plant.
f, j, reactor water dissolved oxygen level (ppb), side view, i feed water dissolved hydrogen pilgrimage (op m >), ◇ indicates reactor output is 81%, ◆ indicates 95% This is the case.

As can be seen from this, as the hydrogen concentration in the feed water is increased, dissolved oxygen in the furnace is reduced.

These lines 14 rows 1-3B hydrogen injection test (Koi'Ct, t, hydrogen dissolved by one person i'? Oxygen reduction effect Song indicator, reactor water dissolved acid wood overflow shade), 1. The former is assumed to be flooded with oxygen in the li steam., 1': i is the former in the core,
13 Important as a direct indicator of water quality7
・(ν) is an important parameter that controls the amount of hydrogen injection.In order to maintain the health of vJ and I in high temperature water, the value must be set to 20pp.
It is said that it is necessary to control the temperature to below b.

(Problems to be Solved by the Invention) The method for collecting raw reactor water samples is as described above.
According to this, reactor water flows out of the reactor pressure vessel 9, which is a high-emission Q1 radiation field, and then reaches the reactor coolant purification system heat exchanger 15 or the reactor recirculation system sampling line cooler 16. It takes a considerable amount of time (several minutes). During this time, the temperature is high; the feeling of being alone is maintained.

On the other hand, reactor water that has undergone Q4-ray decomposition due to high-release J-ray damage in the reactor core is thought to contain oxygen, hydrogen, and hydrogen peroxide. Among these, oxygen and hydrogen are Although hydrogen peroxide is stable at around the reactor temperature (approximately 280°C), it is known that hydrogen peroxide t,-1 rapidly thermally decomposes1, and when there is no hydrogen in the reactor water (
, it simply decomposes into water and oxygen, but if oxygen and hydrogen coexist in the system, the reaction becomes complicated.7 From the recombination reaction between hydrogen peroxide and hydrogen, hydrogen peroxide acts catalytically. Recombination reactions between oxygen and hydrogen proceed in parallel. The following three reactions will cause the composition ratios of oxygen, hydrogen, and hydrogen peroxide in the reactor water to change dramatically.

2+-1202→2H20+02・・・・・・・・・・
...(2) To1202+) [2→2H20...
・・・・・・・・・・・・ (3) 2112+02→2H2
0・・・・・・・・・・・・・・・・・・・・・(4) This situation is shown qualitatively as shown in FIG.

The figure shows 4.5% for a chemical balance of 10 types or more containing active species.
The evaluation is based on a plan that simulates actual chemical changes by assuming 0 or more mutual chemical reactions, and the vertical axis is 02 and H2.
, ]-1202 small ♀) (arbitrary unit), the horizontal axis is the holding time at a high temperature (28()'C). As can be seen, although the reactor water that exits the reactor pressure vessel 9 initially contains hydrogen peroxide, this hydrogen peroxide quickly disappears due to thermal decomposition, and the composition of oxygen and hydrogen also changes. It's changing. It should be noted that hydrogen peroxide is not simply converted to oxygen by decomposition, but has the effect of promoting the recombination reaction of oxygen and hydrogen into water.

Therefore, with the current sampling method, the raw material r in the reactor core is
It can be said that it does not necessarily represent the reactor water v1. Herein lies a problem with the prior art.

However, at present, there is no well-established method for evaluating the condition inside the furnace with good viscosity from the data obtained by 4 non-bringing, and there are indirect methods such as predicting by cutting as shown in Figure 4. I don't know.

On the other hand, in hydrogen injection technology, it is necessary to accurately understand the effect of hydrogen injection on reducing dissolved oxygen in the furnace.
It is necessary to understand the presence of hydrogen peroxide as well as oxygen.It is also important to understand the presence of hydrogen peroxide.

As described above, the present invention provides an apparatus for collecting and analyzing reactor water under conditions closer to those in the reactor pressure vessel, and controlling the amount of hydrogen injection during hydrogen injection operation based on the results. :? The purpose is to provide information.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention includes the following components. 1. However, the present invention includes a cooler and a depressurization mechanism that pumps and cools the reactor water in the reactor pressure vessel and cools it for 30 minutes in the reactor containment vessel, and a depressurization mechanism downstream of this depressurization mechanism. A sample analysis rack installed in the reactor containment vessel, a hydrogen injection amount adjustment device that uses dissolved oxygen from the sample analysis rack as an input signal and outputs an appropriate amount of hydrogen injection, and this hydrogen injection amount. This is a hydrogen injection amount control device for a nuclear reactor, characterized in that it is equipped with a hydrogen gas injection amount adjustment rack that inputs the output signal 8 of the adjustment device and injects hydrogen into the water supply system piping.

(Function) A cooler will be installed at a position where the trial tank will be cooled less than 10 seconds after the reactor water flows out of the Q1 line field in the reactor pressure vessel. This time of 10 seconds means that the change in oxygen and hydrogen concentration is 1 in the needle tube evaluation shown in Figure 4.
This is determined as the time within 0%. The sample is 40°
It shall be cooled to below C.

The cooled sample is then taken to an analysis rack via collection piping and the water quality is measured.

Furthermore, the water quality data obtained in this way,
We will also monitor the dissolved oxygen concentration and install a device that injects hydrogen into the water supply system to control the concentration so that it is below the target value.

In a device configured in this way, the reactor water and other chemical components are cooled and fixed before their composition changes.
The water quality inside the reactor pressure vessel can be accurately determined. As a result, it becomes possible to control the appropriate amount of hydrogen injection in the hydrogen injection operation.

<Embodiment> Hereinafter, an embodiment of the hydrogen injection amount adjusting device into a nuclear reactor according to the present invention will be described with reference to FIG.

In FIG. 1, a main steam pipe 2 is connected to the upper side of a reactor pressure vessel 9 containing a reactor core 1, and a high pressure turbine 3 and a low pressure turbine 4 are connected to the downstream side of the main steam pipe 2. A condenser 5 is connected to the downstream side of the low-pressure turbine 4, and the condenser 5 is connected to the condensate purification system "/" through the condensate pump (3). System 7 (, 1 water supply system piping B+, h (- via condensate pump 8a - (1
3i - One side of the riW9 is connected.

A recirculation system piping 11 is provided from the bottom point A of the reactor power vessel 9 to the side surface of the nuclear potash 1-power vessel 9) leading to the recirculation pump 10, and a recirculation system piping 1'1 is provided. The pipe 12a of the purification system 12 is branched to the heat exchanger 1 [) - furnace cooling system 1], and this pipe 12a
Connected to IJ water supply system piping 8.

Branched from the recirculation system piping 11, the cold JID device 1 ('l) is connected, and this cold J1 [1 device 1 (U0)
The F mechanism '17 is connected. This reduced tsubo VJ, structure
17 is a sample analysis [-] installed outside the reactor containment vessel.
It is connected to 7tsuku'14.

The output signal from the sample analysis rack 14 is output from the hydrogen injection amount adjustment device 18 and outputs 1 and 11 are sent to the hydrogen injection amount adjustment device 18. It is input to the adjustment rack 19. 3 (The 1 m adjustment sock 10 is connected to the hydrogen gas supply device 2C) +1', 3 and the force adjustment hook 21 of the water slug 1f.Hydrogen gas injection amount adjustment rack 19 condensate) is connected to the downstream piping of the child system 7.

Here, steam enters the reactor core, and this steam passes through the steam casing '2 to the high turbine 3 and the low turbine 4.The steam that has done this is condensed It is condensed in the vessel 5 and sent to the condensate pump 6 and the condensate purification system 7.
(It is sent to the reactor water supply system, and the water supply bong, 7'B
By! j? The reactor is pressurized and injected into the reactor container 9.

In addition, the reactor water is forcibly circulated by a recirculation bong 110, and the part (a) is purified by a reactor coolant recirculation pump 11 and a reactor cold 1, 1 material purification system 12. After that, return to reactor water supply.

In Example 43 above, the reactor water sampling point is set to the recirculation pump 1 flow (-1) of the reactor repurification system (1).
Set it at a position close to ゛. 1i) Right time is 10
A. Cool the sample to below 40°C. Thereafter, sample 1':1 reduced by JF reduction machine 17 is guided to sample analysis rack 1/'l. In this analysis rack 171, the dissolved acid concentration is continuously monitored by 5". In addition to the dissolved acid detection, dissolved hydrogen (43 degrees), peroxide water Measurement of water depth J3 and other water quality data is also carried out as necessary.

Subsequently, this dissolved oxygen) surface is converted into electricity (J) and supplied to the hydrogen injection amount control device 1B (J"1), which then controls the flow rate control valve '19 to adjust the amount of hydrogen gas. An electric signal indicating the opening degree is transmitted.Thus, between this bulge, the hydrogen gas supply device 20 and the hydrogen gas 1
]1. - 43 pieces of water adjusted to a predetermined pressure are continuously supplied to the water supply system through a force adjustment system 2''1.

Next, as an effect of this embodiment, cooling is performed for 1.1 hours per head, compared to the conventional sample collection method in which the sample is kept at a high temperature for a long time. I will give a more accurate evaluation. Based on this data, the amount of hydrogen to be injected into the feed water is determined by exactly 1lll Hi to the dissolved oxygen 91α, which has very little effect on the wire properties of the reactor internal structure H. - It becomes extremely easy to do so. According to the present invention, conventionally indirectly evaluated/;
::It is possible to directly (and double-evaluate) water accumulation♀.

In addition, as another embodiment, there is an example in which the sample sampling point is installed outside the reactor containment vessel or in the reactor pressure vessel itself.

31. Hydrogen iU can be placed at any position in the reactor feed and condensate system. The configuration, operation J3, and effects in these cases are similar to those of the above-mentioned embodiments.

[Effect of the invention] According to the present invention, reactor water is transferred to the reactor
Since it is possible to collect hydrogen in a state close to '-1, it is possible to control the amount of hydrogen injected into the water supply system to an appropriate level by using the dissolved oxygen (dissolved oxygen) as a human parameter. .

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a system diagram showing the conventional BWR sub-system and reactor water sample collection system, and Fig. 3 is a system diagram showing the conventional BWR sub-system and reactor water sampling system. Figure 4 is a characteristic diagram showing an example of the results of a water supply hydrogen injection test. An evaluation example is shown in Figure 11 (-'). 1... Core 7... Condensate purification system 9... Reactor 8 power vessel 12... Reactor cooling shrine purification system 13...
・・・・・・・Limbling line 14・・・・・・・・・・
・Trial Oni 31 Analysis Rack 15・・・・・・Reactor cold 2J'l shrine purification system heat exchange agreement: 16・・・・・・・・・
Cooler 17...Excellent 11) Structure 18...
・・・・Hydrogen)〜G Bow Adjustment Device 19・・・・・・・
・Hydrogen scum injection height adjustment rack 20...Hydrogen scum supply device 21...Hydrogen scum JT force adjustment rack Applicant: Toshiba Corporation Patent attorney Toshiba Suyama − Figure 1: Figure 2: Figure 3: j2)
(Meeting) 4th itsu 1

Claims (1)

[Claims] (1) A cooler and a decompression mechanism installed inside the reactor containment vessel that sample and cool the reactor water in the reactor pressure vessel, and a decompression mechanism installed downstream of this depressurization mechanism outside the reactor containment vessel. A hydrogen injection amount adjustment device that uses dissolved oxygen from this sample analysis rack as an input signal and an appropriate amount of hydrogen injection as an output signal, and a hydrogen injection amount adjustment device that inputs the output signal of this hydrogen injection amount adjustment device and supplies water. 1. A hydrogen injection amount control device for a nuclear reactor, comprising a hydrogen gas injection amount adjustment rack for injecting hydrogen into system piping.