JPS59116581A - Device of removing hydrogen in reactor container or pressurevessel - 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 device for removing hydrogen in a nuclear reactor containment vessel or a reactor pressure vessel, and in particular to a device for removing hydrogen in a nuclear reactor containment vessel or a reactor pressure vessel, and in particular to a device for removing hydrogen in a nuclear reactor containment vessel or a reactor pressure vessel, and in particular to a device for removing hydrogen in a nuclear reactor containment vessel or a nuclear reactor pressure vessel. The present invention relates to a hydrogen removal device suitable for treating a large amount of hydrogen generated in a short period of time in a multi-nuclear reactor pressure vessel (abbreviated as Zr-H20 reaction), and furthermore, in a reactor containment vessel storing it.

[Prior art]

FIG. 1 is a system diagram of a conventional flammable gas treatment system (abbreviated as Fe2) for removing hydrogen gas present in the containment vessel of a boiling water reactor (abbreviated as BWR). Fe2 is
Upstream isolation valve 1, flow control valve 2, blower 3, recombiner 4
, a cooler 5, a steam separator 6, a downstream isolation valve 7, a recirculation amount control valve 8, and a closed loop f consisting of piping 9 connecting these, and connected to the upper and lower parts of the reactor containment vessel 10. 11.
12 has been done.

When a loss of coolant accident occurs in a nuclear reactor, Fe2 is activated, and the upstream isolation valve 1, flow control valve 2, and downstream isolation valve 7 are opened. Meanwhile, inside the reactor pressure vessel (not shown), hydrogen gas and oxygen gas are generated by the Zr-H20 reaction caused by Zircaloy, which is the material of the fuel cladding tube, and by the radiolysis of water caused by the radiation emitted from radioactive materials such as nuclear fission products. occurs. (Of course, when fuel failure does not occur, the radiolysis of water due to the shielding effect of the fuel cladding is small.) Hydrogen and oxygen gas leaked from the reactor pressure vessel into the reactor containment vessel 10 and containment Nitrogen gas sealed in container 10 is sucked out from containment container 10 by blower 3 through valves 1 and 2 and sent to recombiner 4, where oxygen and hydrogen are recombined to form water.

The water and nitrogen gas generated by the recombination are cooled in the cooler 5 and then enter the steam/water separator 6, from which part of the nitrogen gas is released due to excessive temperature rise in the recombiner 4 (recombination causes heat generation). In order to prevent this reaction, the gas is recirculated to the upstream side of the blower 3 via the recirculation amount control valve 8, and dilutes the concentration of the hydrogen gas and oxygen gas entering the recombiner 4.

The remaining nitrogen gas and water are stored in the pressure suppression chamber 1 at the bottom of the containment vessel 10.
3, the nitrogen gas returns to the containment vessel (dry well) 10.

As described above, conventional Fe2 reduces the concentration of hydrogen and oxygen gas in the reactor containment vessel 10 by combining oxygen gas and hydrogen gas and returning them to water. If the abundance ratio of hydrogen and oxygen in the containment vessel lo is 2:1 and the recombination capacity of the recombiner 4 is greater than the amount of hydrogen and oxygen generated, the concentration of hydrogen and oxygen gas in the containment vessel 10 is can be kept low. However, at present, the recombiner 4 has a K! If the time required for the Z r
In the -H20 reaction, only hydrogen gas is generated as shown in the following equation, and oxygen, which is the recombination partner in the recombiner 4, is not generated, so the recombiner 4 does not exhibit a satisfactory effect.

Zr + 2H20-Zr02+ 2H2 Considering this in more detail, during the operation of a nuclear reactor, in order to prevent the explosion of hydrogen generated in the reactor containment vessel, air is replaced with nitrogen gas to reduce the amount of oxygen in the containment vessel. The standard is to keep it below 4% at all times. Since it is technically difficult to completely eliminate the amount of oxygen in the containment vessel, the amount of residual oxygen in the containment vessel during normal operation of the reactor is 1.
It is thought to be in the range of 1 to 4.

On the other hand, at present, Zr present in the core during a loss of coolant accident
A safety analysis of the reactor is being carried out assuming that 0.73% of the total amount (approximately 2.7 tons) will react with water. This 0.73% l r
-The amount of hydrogen gas produced by the H20 reaction is approximately 11ONm3
Since the amount of oxygen required to combine with this amount is equivalent to 1% of the volume of the dry well portion of the containment vessel (7900 m3), the amount of residual oxygen described above is sufficient.

However, if Zr of 4 or more in the core causes a Zr-H20 reaction, even if it is assumed that the amount of residual oxygen is 4 or more, the amount of oxygen is insufficient and hydrogen gas that is not recombined remains. Therefore, the possibility that 4% or more of the Z r -H20 reaction actually occurs cannot be denied.

The Zr-H20 reaction becomes noticeable when the reactor core is exposed and the temperature of the fuel cladding reaches 1000°C or higher, and this is coupled with the fact that it is an exothermic reaction and the generated hydrogen inhibits heat transfer. This reaction increases as the temperature rises rapidly, but when the temperature of the fuel cladding becomes low due to the exponential decrease in decay heat and the re-flooding of the core due to the action of the emergency core cooling system, this reaction (
d stop learning. Usually, hydrogen is generated by the Zr-H20 reaction within one hour after the accident occurs. On the other hand, radiolysis of water continues as long as the emission of alpha and gamma rays is not stopped. In other words, radiolysis of water continues for a long period of time, gradually decreasing.

As an example, Fig. 2 shows that the amount of residual oxygen in the containment vessel is 3%, and due to loss of coolant, Zr-010 in the multiple core is
This figure shows the change in the concentration of hydrogen and oxygen in the containment vessel after an accident occurs when hydrogen reacts with H2O. Until about 6 minutes after the accident, the hydrogen concentration increases rapidly due to the Zr-H20 reaction. After that, the Zr-H20 reaction stops and only water radiolysis continues, and the concentrations of hydrogen and oxygen continue to rise slightly, but the rate of soil elevation increases as the oxygen-hydrogen bonding efficiency of Fe2 gradually improves. After FC8 rated operation, the concentration of hydrogen and oxygen decreases. As shown in the shaded area in Figure 3, oxygen and hydrogen have a volume ratio of 5% or more for the former and 4% for the latter.
An explosion occurs in the above cases. In the case shown in Figure 2, if hydrogen and oxygen are mixed evenly, an explosion will not occur because the oxygen concentration is below the explosive limit, but if oxygen gas is unevenly distributed, there is a risk that a local explosion will occur. Also, as mentioned above, the recombiner 4
Since it takes 3.5 hours from startup to the rated operating state, it is possible that the recombination efficiency is insufficient during that time, and even if this time is shortened, the hydrogen gas generated by the Zr-H20 reaction will be Since the concentration of oxygen gas is low compared to the concentration of oxygen gas, recombination is not performed satisfactorily, and it cannot be expected to effectively reduce the hydrogen concentration. Furthermore, a high hydrogen concentration within the containment vessel means high pressure, which is also undesirable in that a large amount of nuclear fission products within the containment vessel leaks to the outside.

The conventional technique for removing hydrogen within the reactor containment vessel has been described above. Next, the conventional technique for removing hydrogen generated within the reactor pressure vessel will be explained with reference to FIG. 4. In FIG. 4, 14 is a B reactor pressure vessel stored in the containment vessel IO, 15 is a main steam isolation valve connected to the pressure vessel 14, 16 is a turbine, 17 is a condenser, and 18 is a It is a water pump. Oxygen and hydrogen produced in the reactor core by radiolysis of water pass through a condenser 17 together with steam passing through a turbine 16, where they are recombined in a recombiner 19 attached thereto and removed as water. However, rare gases are processed by the rare gas hold rough 0 system 20. In this way, under normal conditions, oxygen and hydrogen in the primary cooling system are treated by the operation of the recombiner 19, so problems such as hydrogen explosion do not occur. However, when a loss of cooling water accident occurs, the main steam isolation valve 15 closes, and as a result, hydrogen and oxygen generated within the pressure vessel 14 are accumulated in the pressure vessel 14FrJ, and their concentration increases. In other words, the temporal changes in the concentration of oxygen and hydrogen in the reactor after a loss of coolant accident is as shown in Figure 5.
As mentioned above in FC8, the hydrogen concentration is Z r −H2
The Zr-H20 reaction shows a rapid rise in the initial stage of the accident, and then the temperature of the fuel cladding tube drops and the Zr-H20 reaction is terminated (hydrogen gas is generally generated by this Zr-H20 reaction within one hour after the accident occurs). ) However, as water continues to undergo radiolysis, the concentrations of oxygen and hydrogen increase, albeit slightly. Oxygen and hydrogen generated in the pressure vessel 14 after an accident cannot be removed by the recombiner 19, and there is a risk of an explosion within the pressure vessel. The aforementioned Fe2 fd, especially Z
As already mentioned, it is not possible to take satisfactory measures in the early stages of an accident when the r-H20 reaction is significant, and there is a possibility of an explosion inside the containment vessel or escape of fission products.

As described above, the above-mentioned conventional technology has the disadvantage that it is not possible to satisfactorily remove hydrogen that is generated in large quantities due to the Z r -H20 reaction in a short period of time after an accident occurs. It could not be said that there was no risk of pressure rise, hydrogen explosion, or escape of fission products.

[Purpose of the invention]

An object of the present invention is to remove hydrogen gas that rapidly increases in a reactor containment vessel or a reactor pressure vessel within a short time after a loss of coolant accident occurs, and to prevent a sudden increase in the concentration of hydrogen gas in these vessels. In order to provide hydrogen removal equipment,
This is an attempt to compensate for the above-mentioned conventional technology which is unable to cope with the generation of hydrogen due to the Zr-H20 reaction that occurs early after an accident occurs.

[Summary of the invention]

The first invention relates to a device for removing hydrogen gas in a nuclear reactor containment vessel, and its feature is in a nuclear reactor containment vessel.

The present invention is equipped with a hydrogen trap made of a hydrogen storage metal that is brought into contact with the hydrogen gas in the container.

The second invention relates to a device for removing hydrogen gas in the pressure vessel of a boiling water reactor, and its feature is that from the top of the pressure vessel of the boiling water reactor to the pool of the pressure suppression chamber in the reactor containment vessel. A pipe line leading to water is provided, and a pressure reducing valve and a hydrogen trap made of a hydrogen storage metal located downstream of the pressure reducing valve are provided in this pipe line.

The third invention relates to an apparatus for removing hydrogen gas in a reactor containment vessel, and its characteristics include oxygen injection in which oxygen is injected from outside the closed loop into the oxygen-hydrogen recombiner in Fe2 forming a closed loop as described above. The point is that the device was installed.

As the hydrogen storage metal, it is preferable to use, for example, Mg or a Mg-Ni alloy. Originally, hydrogen tends to diffuse easily into metals, and hydrogen storage metals were developed for storing hydrogen gas. It has the following percentage characteristics compared to other materials.

(1) The amount of hydrogen absorbed and released is large, and the speed is fast.

(2) There is little performance deterioration even after hydrogen storage-desorption cycles, and reuse is possible.

(3) It is relatively inexpensive.

When the hydrogen storage metal comes into contact with hydrogen gas, the following Mg-Ni
As shown in the alloy example, metal hydrides are formed and hydrogen is absorbed.

This is a reversible reaction, and the metal hydride gives an amount of heat equivalent to the heat of formation and does not release the force or occluded hydrogen.

The hydrogen storage properties of Mg are shown in FIG. The middle part of the figure is an absorption equilibrium line, in which hydrogen is occluded in the shaded region A, and hydrogen is released (dissociated) in the region B on the opposite side. Regarding the first invention, calculation results have been obtained that the maximum temperature in the dry well section of the reactor containment vessel in the event of a loss of coolant accident does not exceed 149°C. Therefore, it must have hydrogen storage capacity even at 149°C. In this respect, Mg (dissociation temperature 284°C), Mg
2N1 (250°C) is suitable. Looking at the second invention, it is confirmed that the conditions that the hydrogen storage metal is subjected to in the event of a loss of coolant accident are actually in the area C in Figure 6, so if Mg is used, sufficient hydrogen storage capacity can be ensured. .

The hydrogen storage capacities of Mg and Mg 2N i are 7.6 and 3.6 Mg, respectively. The 10th unit of Zr in the reactor core is Zr
Assuming that -H20 reaction occurs, the amount of hydrogen generated is approximately 120 kg (2688 Nm3), and the amount of Mg required to absorb this is 1580 kg.
It can be said that this is an amount that poses no practical problem.

If these are further distributed, the amount in each can be further reduced. For example, if 18 lines of pipes were provided in the second invention, the hydrogen storage metal Mg for each line would be 882, which would cause no practical problems.

Note that hydrogen storage metals generally have the property that they exhibit the best storage capacity in dry gas. The pressure reducing valve in the second invention is provided from this point of view, and is for converting saturated steam within the pressure vessel into superheated steam to provide drying properties.

[Embodiments of the invention]

FIG. 7 shows an embodiment of the first invention for removing hydrogen within the reactor containment vessel. In this embodiment, a filter 2 is installed in the middle of the conventional Fe2 recirculation piping shown in FIG.
1, a binoculars pipe 33, and a bypass valve 34. When a loss of coolant accident occurs, Fe2 is operated and the gas in the containment vessel IO is supplied to the recombiner 4. However, since the recombiner 4 has a very low recombination ability immediately after starting, the combination of oxygen and hydrogen does not occur, and the gas passes through the cooler 5 and the steam/water separator 6 and reaches the filter 21.

Here, hydrogen is stored in the hydrogen storage metal, and the remaining gas enters the pressure suppression chamber 13 via the bypass pipe 33 and is provided for the next circulation.

The oxygen-hydrogen bonding efficiency of the recombiner 4 improves as time passes after the accident, but since a large amount of hydrogen was generated in the Zr-H0 reaction at the beginning of the accident, the ratio of hydrogen to oxygen is large, and the recombiner 4 Excess hydrogen that is not combined with water is separated from water in the steam-water separator 6 and stored in the filter 21. As more time passes, the abundance ratio of hydrogen and oxygen becomes 2:l, and the capacity of the recombiner 4 becomes sufficient, all of the hydrogen and oxygen entering the recombiner 4 combine to form water 9, and the filter 21
There will be no more hydrogen to absorb. The concentration reduction effect of this embodiment is as shown in FIG. 8, in which hydrogen generated in large quantities at the early stage of an accident is captured by the filter 21, and after the recombiner 4 reaches its rated operation, the hydrogen is By performing oxygen-hydrogen bonding, it is possible to prevent an increase in concentration (and therefore pressure) of hydrogen gas and oxygen gas in the containment vessel IO. Note that the filter 21
requires no maintenance as long as the element does not store hydrogen.

In this embodiment, since the filter 21 is provided downstream of the steam-water separator 6, surplus hydrogen that is not combined in the recombiner 4 is captured, so that the concentration of hydrogen and oxygen in the containment vessel 10 is well-balanced. There is an effect that hydrogen trapping efficiency is reduced, and that the hydrogen trapping efficiency is not reduced because the filter element is not wetted. If the filter 21 is provided upstream of the recombiner 4, oxygen gas may remain in the containment vessel 10, and it is thought that the filter 21 will become wet, reducing its hydrogen capture efficiency.

9 to 13 show typical structures of the above filter. In FIG. 9, a granular hydrogen storage metal 25 is placed in a case 22, a baffle 24 is provided, and a wire mesh 23 for preventing particles from falling off is provided at the entrance and exit. FIG. 10 shows a case 22 with a large number of baffles 26 made of hydrogen-absorbing metal.
FIG. 11 shows a case 22 in which a large number of round pipes 27 made of hydrogen-absorbing metal are arranged in the direction of gas flow, and the gas flows inside and outside the pipes. Fig. 12 shows a case 22 in which a large number of plate-like fins 28 made of hydrogen-absorbing metal are provided behind a perforated plate 29 inside the case 22, and Fig. 13 shows a case 30 in which hydrogen-absorbing metal wires are assembled in a mesh shape. 22
It is contained within. In any of the above filter examples, the hydrogen storage metal has a large surface area and is in sufficient contact with the hydrogen gas flowing inside the case to increase the hydrogen trapping efficiency.

Hydrogen trapping capacity and trapping speed can be further increased by making the filter element porous, such as sintered metal.

FIG. 14 shows another embodiment of the first invention for removing hydrogen within the reactor containment vessel. In this embodiment, a hydrogen storage metal 31 formed in a triple cylindrical shape is installed inside a dry well head 32, and hydrogen gas has a specific gravity higher than other gases such as oxygen and nitrogen present in the containment vessel 10. Hydrogen is quickly captured by focusing on the fact that hydrogen is small and therefore collects in the upper part of the container 10. The hydrogen storage metal 31 can be removed from the container 10 together with the dry well head 32,
Further, although not shown, the aforementioned Fe2 is connected to the containment vessel IO. According to this embodiment, since hydrogen is captured regardless of the blowing capacity of the Fe2 blower 3, there is an effect of suppressing the hydrogen concentration in the containment vessel 10 even lower, as shown in FIG. 15. Another important effect is that hydrogen can be captured even if conventional Fe2 becomes ineffective due to power loss or the like.

FIG. 16 shows still another embodiment of the first invention for removing hydrogen within the reactor containment vessel. An isolation valve 39 and a tank 35 containing hydrogen-absorbing metal particles 36 are provided above the noizo 40 passing through the dry well head 32, and a nitrogen gas injection pipe sealed with a valve 41 is connected to the tank 35. A plurality of baffles 37 are provided within the containment vessel 10 with a slope toward the receiving tray 38. Although not shown, the aforementioned Fe
2 is connected to the containment vessel 10. When the valve 41 is opened to supply nitrogen gas to the tank 35 and the isolation valve 39 is opened in response to a detection signal of a loss of coolant accident or a detection signal of hydrogen concentration in the container 10, the hydrogen storage metal grains 36 are removed from the containment vessel 10.
The water ejects inside and falls to the saucer 38 according to the baffle 37. During this time, the hydrogen storage metal particles 36 store hydrogen, and the container 1
Rapidly lower the hydrogen temperature within 0. In this embodiment, since the hydrogen storage metal is in the form of particles and falls within the container 10, contact with hydrogen gas increases effectively, increasing the hydrogen storage effect.

FIG. 17 shows still another embodiment of the first invention for removing hydrogen within the reactor containment vessel. There are many pipes inside the reactor containment vessel, including coolant recirculation system pipes, main steam pipes, and water supply pipes. A heat insulating material 43 is wrapped around the outer periphery of these pipes 42,
Further, its outer periphery is usually covered with a thin metal plate 44. In this embodiment, the thin metal plate 44 is made of a hydrogen-absorbing metal, which has the effect of not requiring a special space for installing the hydrogen-absorbing metal.

Alternatively, it is also possible to spray or apply hydrogen storage metal powder together with a binder to the periphery of the heat insulating material cover 44 and the inner wall of the containment vessel 10.

In these embodiments as well, the containment vessel 10 contains conventional Fe.
2 are connected.

FIG. 18 shows an embodiment of the second invention for removing hydrogen within the reactor pressure vessel. 45 is a hydrogen gas detector connected to the reactor pressure vessel 14. 46 is a pressure reducing valve provided at the upper part of the pressure vessel 14 and activated by a signal from the detector 45; 47 is a hydrogen storage device connected downstream of the pressure reducing valve 46; 48 is a pipe connecting these; The end branches off from the main steam pipe via a relief valve 49 and is connected to the pressure suppression chamber 13 at 70.
- connected to an exhaust pipe 50 which is open during addition of water;

52 is the conventional Fe2 connected to the containment vessel 10.
It represents.

In the event of an accident, when the main steam isolation valve 15 is closed, the oxygen and hydrogen gases generated in the reactor core as described above accumulate in the pressure vessel 14. When the hydrogen concentration detected by the hydrogen detector 45, which constantly monitors the hydrogen concentration in the steam within the pressure vessel 14, exceeds a threshold value, the pressure reducing valve 46 is activated via the electric circuit 51. By operating the pressure reducing valve 46, the saturated steam in the pressure vessel 14 becomes superheated steam and is led to the hydrogen storage device 47, where hydrogen is removed. The steam from which hydrogen has been removed is discharged together with oxygen through the rear exhaust pipe 50 of the relief valve 49 into the pool water of the pressure suppression chamber 13.

The hydrogen storage device 47 used in this embodiment can have a structure substantially similar to that shown in FIGS. 8 to 12.

The pressure reducing valve 46 has the function of converting saturated steam into superheated steam as described above. Since hydrogen storage metal has the highest hydrogen storage efficiency in a dry state, dry steam is introduced to the hydrogen storage device 47 by providing the pressure reducing valve 46.

FIG. 19 shows temporal changes in the oxygen and hydrogen concentrations in the reactor water after the occurrence of a loss of coolant accident in the embodiment of FIG. 18 in which hydrogen is removed from the reactor pressure vessel.

In the figure, the solid line curve is the case where this embodiment is not applied, and the dashed line curve is the case where this embodiment is applied. When this embodiment is applied, rapid Z r
A transient hydrogen concentration peak appears because the -H20 reaction cannot be followed, but at this time the amount of oxygen in the reactor water is too small to cause an explosion. Thereafter, as time passes, the amount of hydrogen in the hydrogen storage metal reaches saturation, and after several hours, the oxygen and hydrogen gas flowing through the hydrogen storage device 47 passes through the pool water from the exhaust pipe 50 into the containment vessel without storing hydrogen. Move within 10. However, the hydrogen generated at this point is mainly due to the radiolysis of water due to the radiation of fission products, and is relatively small.
can be adequately processed.

In other words, Fe226 requires 3 to 4 to reach the rated operating state.
Although it takes time, by the time the hydrogen storage metal reaches saturation and hydrogen has migrated into the containment vessel 10, Fe2 is in its rated operating state and can be expected to perform its function. There's no danger.

FIG. 20 shows another embodiment of the second invention for removing hydrogen within the reactor pressure vessel. In this embodiment, an oxygen/hydrogen recombiner 53 is connected in series to the downstream side of the hydrogen absorber 47 in the embodiment shown in FIG. 18. The oxygen generated in the pressure vessel, which could not be recovered, can be treated.

Since the recombiner 53 takes 3 to 4 hours to start up, the hydrogen generated in the early stages of an accident is mainly removed by the hydrogen storage device 47, but by the time the hydrogen storage metal reaches saturation several hours after the accident, it is regenerated. The combiner 53 is in a rated operating state and can combine oxygen and hydrogen flowing out from the core. Therefore, the amount of oxygen and hydrogen gas discharged into the containment vessel 10 can be suppressed below the explosive limit, and Fe
226 can be reduced.

FIG. 21 shows an embodiment of the third invention in which the hydrogen concentration in the reactor containment vessel is reduced by injecting oxygen.

In this system, the recombiner 4 in the conventional FCS loop shown in FIG. 1 is equipped with an oxygen injection device 54, and a gas shading analyzer 55 and a flow meter 56 are installed in the middle of the upstream piping. As mentioned above, in the Zr H20 reaction, no oxygen is generated to recombine the generated hydrogen, which is one of the reasons why the recombiner 4 cannot satisfactorily process the hydrogen gas. According to this embodiment, even if hydrogen is generated by the Zr-H20 reaction during a coolant loss accident, oxygen is By controlling the amount of oxygen injected from the injector 54 and combining hydrogen with an appropriate amount of oxygen in the recombiner 4, an increase in internal pressure within the containment vessel 10 and the risk of explosion can be avoided as much as possible.

〔Effect of the invention〕

According to the first invention, hydrogen gas that increases in the reactor containment vessel in the event of a loss of coolant accident is quickly removed to reduce the pressure and hydrogen concentration in the containment vessel, thereby preventing a hydrogen explosion and containment in the containment vessel. The risk of leakage of fission products from the container can be reduced. According to the second invention, the hydrogen gas generated in the reactor core at the time of the above accident can be quickly removed to reduce the hydrogen concentration in the reactor pressure vessel, thereby reducing the risk of hydrogen explosion within the pressure vessel. Rather, it contributes to core cooling by preventing heat transfer deterioration due to hydrogen gas mixing in the coolant, and therefore suppresses the oxidation reaction of the fuel cladding, reducing its damage and reducing the total amount of hydrogen generated. In addition to this effect, hydrogen gas discharged from the pressure vessel to the containment vessel can be reduced.

In both the first and second inventions, the hydrogen storage metal has a high hydrogen storage rate, a large hydrogen storage capacity,
In addition, these hydrogen storage metals that have once stored hydrogen are chemically stable and do not release hydrogen under the operating environment at the time of a loss of coolant accident, so they can quickly respond to a sudden increase in hydrogen and prevent accidents. Can prevent spread. The hydrogen-absorbing metal that has occluded hydrogen can later release hydrogen by applying the required amount of heat, and has the advantage of being able to be reused with almost no deterioration in performance. Moreover, since the hydrogen storage function of the hydrogen storage metal is spontaneous and does not require an external supply of energy, it is not affected by power outages and has high reliability as a safety equipment for nuclear reactors.

According to the third invention, hydrogen generated by the Zr-H20 reaction, which conventional Fe2 could hardly treat, can be treated by combining with oxygen.

[Brief explanation of the drawing]

Figure 1 is a conventional Fe2 system diagram, Figure 2 is a conventional Fe2 system diagram.
Figure 3 is a diagram showing the explosion limit of a mixed gas of oxygen and hydrogen, and Figure 4 is a diagram showing the changes in hydrogen and oxygen concentrations in the reactor pressure vessel. Figure 5 is a diagram showing changes in oxygen and hydrogen concentrations in reactor water after an accident occurs in the case shown in Figure 4, Figure 6 is a schematic diagram of a BWR secondary cooling system equipped with a hydrogen storage metal Mg. Diagrams showing the characteristics, Figure 7 is a system diagram showing an embodiment of the present invention for removing hydrogen in the reactor containment vessel, and Figure 8 shows changes in hydrogen and oxygen concentrations in the containment vessel according to the embodiment of Figure 7. 9 to 13 are sectional views showing some examples of hydrogen storage filters used in embodiments of the present invention, and FIG. 14 is a cross-sectional view showing some examples of hydrogen storage filters used in embodiments of the present invention. FIG. 15 is a cross-sectional view of the containment vessel showing another embodiment, and FIG. 15 is a diagram showing changes in hydrogen and oxygen concentrations in the containment vessel according to the embodiment of FIG.
16 and 17 are sectional views of the containment vessel showing other different embodiments of the present invention for removing hydrogen in the containment vessel, the first
Figure 8 is a sectional view of the containment vessel showing an embodiment of the present invention for removing hydrogen in the reactor pressure vessel, Figure 19 is a diagram showing changes in the oxygen and hydrogen concentration in the reactor water according to the embodiment of Figure 18, and Figure 20
The figure is a cross-sectional view of the containment vessel showing another embodiment of the present invention for removing hydrogen within the reactor pressure vessel, and Figure 21 is the present invention for removing hydrogen within the reactor containment vessel by injecting oxygen. It is a system diagram showing an example of. 4... Recombiner 5... Cooler 6... Steam-water separator lO... Reactor containment vessel 13...
Pressure suppression chamber 14... Reactor pressure vessel 16...
・Turbine 17... Condenser 19...
Recombiner 21...Hydrogen storage device 31...Hydrogen storage metal cylinder 36...Hydrogen storage metal particles 37...
・Baffle 38...Saucer 42...Piping
44... Hydrogen storage metal cover 45
... Hydrogen concentration detector 46 ... Pressure reducing valve 47 ...
Hydrogen storage device 49... Relief valve 50... Exhaust pipe 52... FC853... Recombiner, 54... Oxygen injection device 55... Gas concentration analyzer 56... Flow meter agent Honda small
i flat ¥1 Figure 1 ``Ball Figure 3 Hydrogen concentration Figure 4 Figure 1 m = -■ H line spacing after the accident (hr) 1 item 1 degree C) Time after the accident (hr) Figure 9 '24 Fig. 12 Fig. 15 Time after the accident occurred (Nir) Fig. 19 Time after the accident (Nir) Fig. 20 448-448 Energy Research Institute Co., Ltd., 1168 Moriyama-cho, Hitachi City

Claims (1)

[Scope of Claims] 1. A device for removing hydrogen gas in a reactor containment vessel, characterized by comprising a hydrogen trap made of a hydrogen storage metal and brought into contact with hydrogen gas in the reactor containment vessel. 2. One end is connected to the upper part of the reactor containment vessel, the other end is connected to the lower part of the containment vessel, and the closed loop flow path includes a proa, an oxygen hydrogen recombiner, and a steam/water separator in this order in the direction of fluid flow. 2. The device for removing hydrogen gas in a reactor containment vessel according to claim 1, wherein the hydrogen trap is provided downstream of the steam separator. 3. The device for removing hydrogen gas in a reactor containment vessel according to claim 1, characterized in that a hydrogen trap is provided inside the reactor containment vessel. 4. Hydrogen gas in the reactor containment vessel according to claim 1, characterized in that a large number of granular hydrogen traps made of hydrogen storage metal are ejected from the upper part of the reactor containment vessel. removal device. 5. Hydrogen capture consisting of a pressure reducing valve in the pipeline from the top of the pressure vessel of a boiling water reactor to the pool water of the pressure suppression chamber in the reactor containment vessel, and a hydrogen storage metal located downstream of the pressure reducing valve. 1. A device for removing hydrogen gas in a pressure vessel of a boiling water reactor, characterized in that it is provided with a body. 6. The device for removing hydrogen gas in a pressure vessel of a boiling water nuclear reactor according to claim 5, characterized in that an oxygen-hydrogen recombiner is provided in the pipeline downstream of the hydrogen trapping body. 7. A closed loop flow path having one end connected to the upper part of the reactor containment vessel and the other end connected to the lower part of the containment vessel, including a proa, an oxygen hydrogen recombiner, and a steam water separator in this order in the direction of fluid flow; and a device for injecting oxygen into the oxygen-hydrogen recombiner from outside the closed loop.