JP6137972B2 - Method and apparatus for inhibiting corrosion of nuclear reactor structure - Google Patents

Description

  The present invention relates to a method and an apparatus for inhibiting corrosion of a nuclear reactor structure.

  In a nuclear power plant, for example, water (cooling water) for cooling a reactor (reactor structure) is water (pure water) in which the type and concentration of ions contained are controlled in order to suppress corrosion of the reactor. Etc.) are used. However, due to unforeseen accidents, such controlled water cannot be used, and river water, seawater, etc. must be used instead. The sea water etc. that flows may flow in. In addition, after the operation of the power plant is stopped, the corrosive substances may be mixed into the reactor cooling water for some reason during the period until the nuclear reactor decommissioning or large-scale repair work.

  In these cases, since water other than the predetermined cooling water is supplied to the reactor, depending on the ions contained in the supplied water, corrosion of the reactor may be a concern. is there. In particular, when water (seawater or the like) containing a large amount of chloride ions is supplied to the reactor, the concern about the corrosion of the reactor becomes serious.

  Therefore, it is conceivable to use a corrosion inhibitor that suppresses corrosion of the metal so that water containing the corrosion inhibitor is supplied to a nuclear reactor structure such as a nuclear reactor. As such a technique, for example, Patent Document 1 discloses a chemical decontamination in a nuclear power plant by a chemical decontamination processing system in a nuclear power plant that removes radioactive corrosion products attached to a structure in contact with a fluid containing a radioactive substance in the nuclear power plant. A suppression pool water purification treatment step by a treatment pool, and a suppression pool water purification treatment system that purifies the pool water by filtering insoluble impurities in suppression pool water stored in the pressure suppression chamber of the reactor containment vessel; Used in each of the above-mentioned steps when the corrosion inhibitor-containing waste liquid treatment system by the corrosion inhibitor-containing waste liquid treatment system that decomposes and detoxifies the corrosion inhibitor contained in the radioactive waste liquid is carried out approximately simultaneously. Shared equipment / equipment to be used.

JP 2010-223739 A

  In the technique described in Patent Document 1, a corrosion inhibitor is contained in the water in the suppression pool (pressure suppression chamber, reactor structure). Thereby, corrosion of the inside of a suppression pool, the apparatus connected to it, piping, etc. is suppressed. This water is appropriately extracted together with the corrosion inhibitor, and then a new corrosion inhibitor is supplied into the suppression pool. The corrosion inhibitor contained in the extracted water is concentrated after being removed by itself and treated as waste.

  Such waste is usually treated as radioactive waste. Therefore, the larger the amount of waste, the more time is required for processing. In particular, when radioactive materials are mixed into the discharge water from the reactor structure for some reason, this waste may contain a large amount of radioactive materials. For this reason, it may take more time to process the radioactive waste. Further, since the used corrosion inhibitor is extracted and removed as described above, it may be necessary to add a new corrosion inhibitor to the water supplied to the suppression pool. Therefore, the used corrosion inhibitor continues to increase, and the amount of radioactive waste continues to increase with it.

  The present invention has been made in view of the above problems, and the problem to be solved by the present invention is to provide a method and apparatus for inhibiting corrosion of a nuclear reactor structure that can reduce radioactive waste as much as possible.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following . That is, the gist of the present invention is to provide a corrosion inhibitor-containing water supply step for supplying water containing a corrosion inhibitor to a nuclear reactor structure in which seawater containing a radioactive substance is retained, and discharging from the reactor structure. A precipitate generating step of adding a precipitation generator to the seawater containing the corrosion inhibitor and the radioactive substance, and generating a precipitate of the corrosion inhibitor that is re-dissolvable in water; and In the separation step of separating the precipitate generated in the precipitate generation step from the supernatant, in the ionization step of ionizing the precipitate separated in the separation step to obtain water in which the corrosion inhibitor is dissolved, in the ionization step The obtained corrosion inhibitor-added step is added to the water supplied to the reactor structure in the corrosion inhibitor-containing water supply step. And having a flop, and to a method of corrosion inhibition reactor structure. Other solution means will be described later in the embodiment for carrying out the invention.

  According to the present invention, it is possible to provide a method and an apparatus for inhibiting corrosion of a nuclear reactor structure that can reduce radioactive waste as much as possible.

It is a systematic diagram of the water and the corrosion inhibitor which circulate between the nuclear power plant and the corrosion inhibitor of this embodiment in the first embodiment. It is a flowchart when reusing a corrosion inhibitor. It is a systematic diagram of the water and corrosion inhibitor which circulate between another nuclear power plant and the corrosion inhibitor of this embodiment in 2nd Embodiment. It is a systematic diagram of the water and the corrosion inhibitor which circulate between another nuclear power plant and corrosion inhibitor of this embodiment in a 3rd embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (this embodiment) will be described with reference to the drawings.

[1. First Embodiment]
FIG. 1 is a system diagram of water and a corrosion inhibitor circulated between the nuclear power plant and the corrosion inhibitor of this embodiment in the first embodiment. In the first embodiment, the nuclear power plant 50, specifically the reactor building 51 and the turbine building 54 (the steam turbine stored in the turbine building 54 is not shown for convenience of illustration), seawater is inundated. Yes. The reactor pressure vessel 53 and the reactor containment vessel 52 are damaged. Therefore, the cooling water supplied to the reactor pressure vessel 53 leaks from the reactor pressure vessel 53 and the reactor containment vessel 52 and stays with the seawater on the floor of the nuclear power plant 50. Moreover, since these are damaged, radioactive materials, such as cesium, leak from these, and the radioactive material is contained in the said seawater.

  Under such circumstances, in the water treatment in the first embodiment, seawater (retained water) staying in the nuclear power plant 50 by being submerged is pumped up by a pump (not shown). Then, the pumped-up seawater is desalinated after the contained corrosion inhibitor (described later in detail) is removed. Thereafter, a corrosion inhibitor is added to the obtained fresh water, and fresh water containing the corrosion inhibitor is used as water for cooling the reactor in the reactor pressure vessel 53 (reactor structure) in the reactor containment vessel 52. It comes to be supplied. That is, the corrosion suppression apparatus 100 described later removes cesium from seawater containing radioactive substances, particularly cesium, and desalinates it, and the obtained fresh water is supplied to the reactor pressure vessel 53 again.

  Thus, water (seawater and fresh water) is circulated between the nuclear power plant 50 and the corrosion suppression apparatus 100 described later. And a corrosion inhibitor is added to the cooling water (fresh water) supplied to the nuclear power plant 50, and a corrosion inhibitor is also collect | recovered from the water (seawater) discharged | emitted from the nuclear power plant 50. As a result, the corrosion inhibitor is reused and the amount of radioactive waste discharged is reduced.

  Hereinafter, each device shown in FIG. 1 will be described.

〔Constitution〕
The corrosion suppression apparatus 100 includes a reaction tank 101, a sedimentation tank 102, and an ion exchange resin 103. Furthermore, the corrosion inhibiting device 100 of the first embodiment includes a cesium removing device 104, a desalinating device 105, a fresh water tank 106, a concentrated water tank 107, an evaporating and concentrating device 108, and a concentrated waste liquid storage tank 109. . Although details will be described later, in the first embodiment, sodium molybdate (oxo acid salt; dissociates into molybdate ions (ions constituting the oxo acid salt) in water) is used as a corrosion inhibitor to be used. It has been. Furthermore, calcium chloride (which dissociates into calcium ions in water) is used as a precipitation generator for precipitating and collecting corrosion inhibitors (molybdate ions) in water.

  In the reaction tank 101, calcium chloride or calcium ions are added to the accumulated water pumped from the nuclear power plant 50 to generate a precipitate of a corrosion inhibitor. In 1st Embodiment, since water-soluble sodium molybdate is used as a corrosion inhibitor, this precipitation is hardly soluble calcium molybdate (calcium salt of a corrosion inhibitor).

  The sedimentation tank 102 settles and separates the precipitate generated in the reaction tank 101. The separated slurry-like precipitate (calcium molybdate) is supplied to an ion exchange resin 103 described later. Further, the supernatant (including cesium and the like) after the corrosion inhibitor is removed is supplied to a cesium removing device 104 described later.

  The ion exchange resin 103 is made of a hydrogen-type strongly acidic ion exchange resin. By bringing the precipitate into contact with the ion exchange resin 103, calcium ions and hydrogen ions contained in the calcium molybdate are ion-exchanged to generate soluble molybdate ions. As will be described in detail later, the generated molybdate ions are added to the fresh water in the subsequent stage of the fresh water tank 106 instead of sodium molybdate as a corrosion inhibitor or together with sodium molybdate. Thereby, fresh water (cooling water) containing a corrosion inhibitor is supplied to the reactor containment vessel 53, and corrosion of the nuclear power plant 50 in the reactor containment vessel 53 or the like is suppressed.

  Note that calcium constituting calcium molybdate is adsorbed by the ion exchange resin 103. Accordingly, the ion exchange resin 103 is periodically washed with a strong acid such as sulfuric acid or nitric acid, whereby hydrogen ions and calcium ions in the strong acid are ion exchanged, and the ion exchange resin 103 is regenerated. ing. Further, the calcium ions obtained by regeneration will be described later in detail, but in the reaction tank 101, instead of calcium chloride or together with calcium chloride, it is added to the accumulated water pumped up from the nuclear power plant 50. Yes.

  The cesium removing device 104 is a device in which the supernatant after the sediment is removed in the sedimentation tank 102, that is, seawater containing cesium is supplied, and cesium in the seawater is removed. Specifically, the cesium removing device 104 is configured such that an adsorbent such as zeolite is added to seawater, and the cesium is removed by adsorbing cesium on the adsorbent. In addition, adsorption | suction of other radioactive substances is also attained by adsorption agents, such as a zeolite.

  The desalination apparatus 105 desalinates the seawater from which cesium has been removed. Specifically, the desalination apparatus 105 is composed of a reverse osmosis membrane or the like, and can be separated into fresh water and concentrated water containing ions by permeabilizing the reverse osmosis membrane using a high pressure pump (not shown). It is like that. Fresh water obtained in the desalination apparatus 105 is stored in a fresh water tank 106. Concentrated water is stored in the concentrated water tank 107. The fresh water stored in the fresh water tank 106 is supplied to the reactor pressure vessel 53.

  The evaporative concentration device 108 heats and concentrates the concentrated water concentrated in the desalination device 105. That is, steam (water) is separated by heating and boiling concentrated water, and concentrated water containing ions and the like is further concentrated. Further concentrated ions and the like are stored in the concentrated waste liquid storage tank 109 as a concentrated liquid. The obtained water vapor is stored in the fresh water tank 106 after cooling.

[Action]
Next, a method for treating seawater staying in the nuclear power plant 50 using the corrosion suppression apparatus 100 (corrosion suppression method) will be described.

  FIG. 2 is a flowchart when the corrosion inhibitor is reused. In FIG. 2, for simplification of description, steps related to addition and recovery of sodium molybdate or molybdate ions as corrosion inhibitors are mainly shown, and steps related to water circulation are not shown.

  First, sodium molybdate as a corrosion inhibitor is added to the cooling water to the reactor pressure vessel 53 (step S101). Then, cooling water to which sodium molybdate is added is supplied to the reactor pressure vessel 53. As described above, the reactor containment vessel 52 and the reactor pressure vessel 53 are damaged, and the cooling water containing the corrosion inhibitor stays on the floor surfaces of the reactor building 51 and the turbine building 54 and stays with the submerged seawater. It becomes. Therefore, this accumulated water is pumped up by a pump (not shown) and supplied to the reaction tank 101, and calcium chloride is added to the pumped-up accumulated water (step S102). As a result, the molybdate ions in the retained water are combined with the added calcium ions to form hardly soluble calcium molybdate, and a precipitate of calcium molybdate is generated (step S103, precipitate generation step). By these steps, the corrosion inhibitor contained in the staying water of the nuclear power plant 50 is changed into a precipitate and removed from the staying water.

  Next, the retained water containing the precipitate is supplied to the sedimentation tank 102, and is separated into a supernatant and a sediment in the sedimentation tank 102 (step S104, separation step). The separated precipitate is supplied to the ion exchange resin 103 as a slurry of calcium molybdate. Then, in the ion exchange resin 103, calcium ions constituting the calcium molybdate and hydrogen ions in the ion exchange resin 103 are ion-exchanged, so that the calcium molybdate (precipitate) is solubilized (step S105, ionization step). That is, the initially added corrosion inhibitor returns to the form of molybdate ions and is present in water.

  And the molybdate ion obtained in the ion exchange resin 103 is added to the cooling water (fresh water) to the reactor pressure vessel 53 as a corrosion inhibitor instead of the sodium molybdate added in step S101 (step S101). S106). Thus, the cooling water to which molybdate ions are added is supplied again to the reactor pressure vessel 53 without adding new sodium molybdate from the outside.

  On the other hand, in the ion exchange resin 103, there is a limit to the amount of calcium ions supported. Therefore, for example, sulfuric acid or nitric acid is brought into contact with the ion exchange resin 103 to desorb the supported calcium ions, and the ion exchange resin 103 is appropriately regenerated. The desorbed calcium ions are once stored in a tank (not shown). Then, instead of the calcium chloride added in step S102, water containing calcium ions stored in the tank is added to the accumulated water of the nuclear power plant 50 pumped up (step 107). As a result, as in the case of adding calcium chloride, the molybdate ions in the retained water become calcium molybdate to form a precipitate (Step S103 described above). After that, the above steps S104 to S107 are performed. Therefore, sodium molybdate as a corrosion inhibitor is first added (step S101), and further calcium chloride is added (step S102). Thereafter, the corrosion inhibitor is circulated without adding these components. Can be reused.

〔effect〕
According to the corrosion inhibiting method and the corrosion inhibiting apparatus of the present embodiment described above, it is possible to provide a reactor structure corrosion inhibiting method and a corrosion inhibiting apparatus that can reduce radioactive waste as much as possible. As a result, the corrosion of the reactor structure due to the use of the corrosion inhibitor can be suppressed, and the corrosion inhibitor can be used efficiently.

  Moreover, in the corrosion suppression apparatus 100, the molybdate ion is selectively collect | recovered, before desalinating the stagnant water containing seawater with the desalination apparatus 105. FIG. Therefore, the amount of molybdate ions removed in the desalination apparatus 105 and discarded as concentrated water can be greatly reduced. Therefore, the amount of sodium molybdate newly used in the corrosion inhibiting apparatus 100 can be greatly reduced, and the amount of concentrated liquid (that is, radioactive waste) to be discarded can be greatly reduced.

  Furthermore, the recovery of molybdate ions is also performed before the cesium removal apparatus 104 removes cesium. Thereby, it is possible to prevent the molybdate ions from being removed together with cesium, and the molybdate ions can be used more efficiently. For example, when cesium is removed using an adsorbent, molybdate ions are not included, and therefore the amount of cesium adsorbed on the adsorbent can be increased. Therefore, cesium in the retained water can be efficiently removed, and the amount of used adsorbent (ie, radioactive waste) that has adsorbed cesium can be reduced.

  Moreover, in the corrosion inhibitor 100, calcium ions for precipitating molybdate ions are reused as in the case of the corrosion inhibitors. That is, the amount of calcium chloride newly added can be reduced by re-adding calcium ions desorbed by washing the ion exchange resin 103 to the reaction vessel 101. Thereby, similarly to the corrosion inhibitor, the amount of calcium ions removed in the desalination apparatus 105 and discarded as concentrated water can be greatly reduced. Therefore, the amount of calcium chloride newly used in the corrosion inhibiting apparatus 100 can be greatly reduced, and the amount of concentrated liquid (that is, radioactive waste) to be discarded can be greatly reduced.

  Furthermore, the corrosion inhibitor 100 selectively precipitates and recovers the corrosion inhibitor by adding calcium chloride or calcium ions. That is, the radioactive material contained is not precipitated. Therefore, even if it is stagnant water containing a radioactive substance, the corrosion inhibitor can be simply precipitated and recovered simply by adding calcium chloride or the like, and the effects of radiation on workers can be further suppressed. .

  Moreover, since the desalination apparatus 105 is supplied with a supernatant that does not contain (or hardly contains) molybdate ions or the like, the filtration pressure for desalination can be reduced. Therefore, the durability of the reverse osmosis membrane constituting the desalination apparatus 105 can be improved.

[2. Second Embodiment]
Next, the corrosion suppression apparatus of 2nd Embodiment is demonstrated, referring FIG. In FIG. 3, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 3 is a system diagram of water and a corrosion inhibitor that are circulated between another nuclear power plant and the corrosion inhibitor of this embodiment in the second embodiment. A reactor cooling water purification device 60 is connected to the reactor pressure vessel 53, and the purity of the cooling water in the reactor pressure vessel 53 is maintained by the reactor cooling water purification device 60. However, after the operation of the reactor is stopped, seawater or the like may be mixed into the cooling water of the reactor due to an unexpected situation. If it does so, corrosion may generate | occur | produce in the metal material currently used for the apparatus which circulates the reactor pressure vessel 53 and cooling water by the chloride ion etc. which are contained in seawater.

  Therefore, in order to suppress such corrosion, the corrosion suppression apparatus 200 of the second embodiment is provided between the reactor pressure vessel 53 and the reactor cooling water purification apparatus 60. Then, the corrosion inhibitor 200 recovers the corrosion inhibitor in the cooling water of the reactor pressure vessel 53 (which contains a slight amount of radioactive material) and re-adds it to the supplied water. It has become. Specifically, the corrosion inhibitor is recovered immediately after the reactor pressure vessel 53, and the water after the corrosion inhibitor is removed is purified by the reactor cooling water purification device 60. Then, the corrosion inhibitor recovered in the water purified by the reactor cooling water purification device 60 is added again, and then returned to the reactor pressure vessel 53.

  The nuclear power plant 50A is a so-called boiling water reactor (BWR). Specifically, water in the reactor pressure vessel 53 is heated by heat generated from the reactor in the reactor pressure vessel 53, and steam is generated. Then, the generated steam rotates the steam turbine 55 in the turbine building 54, and power is generated by a generator (not shown) connected to the steam turbine 55. And the water vapor | steam after rotating the steam turbine 55 is condensed by the condenser 56, and changes to liquid water. Then, after being filtered by the condensate filtering device 57, the salt is desalted by the condensate desalting device 58, heated by the feed water heater 59, and returned to the reactor pressure vessel 53.

  Since the structure and the processing method of the corrosion inhibiting apparatus 200 that treats the water in the reactor pressure vessel 53 are the same as the treating method in the corrosion inhibiting apparatus 100, detailed description thereof is omitted. However, in the corrosion inhibitor 200, sodium tungstate is used as a corrosion inhibitor, and calcium nitrate is used as a precipitate. In addition, the corrosion inhibitor 200 includes a strong acid contact device 110 that contacts the precipitate with sulfuric acid (strong acid) in order to desorb tungstate ions from the calcium tungstate produced in the reaction vessel 101.

  In the strong acid contact device 110, sulfuric acid is contacted (added) to the slurry containing calcium tungstate produced in the reaction vessel 101, and tungstate ions, which are weak acids, are desorbed (ionization step). Thereby, the tungstate ion as a corrosion inhibitor can be reused. On the other hand, the produced calcium ions react with sulfate ions to form hardly soluble calcium sulfate, and a precipitate is formed. Therefore, unlike the corrosion suppression apparatus 100 of the first embodiment, the corrosion suppression apparatus 200 does not reuse calcium ions.

  Using such a corrosion suppression device 200, the recovery and reuse of the corrosion inhibitor can be suitably performed even in a nuclear plant 50A different from the nuclear plant 50 shown in the first embodiment.

[3. Third Embodiment]
Next, a nuclear plant 50B to which the corrosion suppression apparatus 200 of the present embodiment can be applied will be described with reference to FIG. In FIG. 4, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 4 is a system diagram of water and a corrosion inhibitor circulated between still another nuclear power plant and the corrosion inhibitor of the present embodiment in the third embodiment. A nuclear power plant 50B shown in FIG. 4 is a so-called pressurized water reactor (PWR). Specifically, the nuclear power plant 50B includes a primary cooling water system that transmits heat from the core for generating steam for driving the steam turbine 55 to the secondary cooling water system, and steam generated by the steam generated by the heat from the primary cooling water system. And a secondary cooling water system that drives the turbine 55 to generate power. Heat exchange is performed in the steam generator 61 between the primary cooling water system and the secondary cooling water system. In addition, the primary cooling water system includes a chemical volume control device (not shown) for adjusting the volume of the cooling water when the temperature of the primary cooling water system changes, and a reactor water drainage for maintaining and managing the quality of the cooling water. A salt device 62 (purifying device) and a lithium remover 63 are provided.

  Similar to the second embodiment, seawater or the like may be mixed into the primary cooling water system due to an unexpected situation after the operation of the reactor is stopped. If it does so, corrosion may generate | occur | produce in the metal material currently used for the apparatus which circulates the reactor pressure vessel 53 and cooling water by the chloride ion etc. which are contained in seawater. In particular, since a material having excellent corrosion resistance is used in the primary cooling water system, if chloride ions are mixed, cooling water may leak due to local corrosion such as pitting corrosion, crevice corrosion, and stress corrosion cracking.

  Therefore, lithium hydroxide is added to the primary cooling water system in order to suppress corrosion. However, in the third embodiment, another corrosion inhibitor is added and the corrosion inhibitor 300 collects the corrosion inhibitor. And re-addition. In the third embodiment, sodium molybdate is used as the corrosion inhibitor, and calcium nitrate is used as the precipitation generator.

  The configuration and processing method of the corrosion suppression apparatus 300 for processing the cooling water in the reactor pressure vessel 53 (similar to the second embodiment, but containing a radioactive material) are the treatment in the corrosion suppression apparatus 100. Since it is similar to the method, its detailed description is omitted. However, the corrosion suppression apparatus 300 includes a strong acid contact apparatus 110 that contacts the precipitate with nitric acid in order to desorb molybdate ions from the calcium molybdate generated in the reaction tank 101, as in the case of the corrosion suppression apparatus 200 described above. ing.

  Even in such a nuclear power plant 50B, similarly to the first embodiment, the corrosion inhibitor 300 can be used to suitably recover and reuse the corrosion inhibitor.

[4. Modified example]
Although the present embodiment has been described with reference to the three embodiments, the present embodiment is not limited to the above-described embodiments.

  For example, in the above embodiment, sodium molybdate or the like is used as the corrosion inhibitor, but the corrosion inhibitor is not limited to these. However, in this embodiment, the corrosion inhibitor is used in an environment exposed to radiation. Therefore, the corrosion inhibitor is preferably an inorganic compound from the viewpoint of being hardly decomposed by radiation, and more preferably an oxoacid salt. In addition, the corrosion inhibitor preferably contains a metal, more preferably an inorganic compound containing a metal, and an oxidized corrosion inhibitor that forms a passive film on the metal surface from the viewpoint of higher stability. .

  Specific examples of the corrosion inhibitor include, in addition to the molybdate, tungstate, phosphate, vanadate, etc. Among them, molybdate, tungstic acid are preferable from the viewpoint of easy precipitation. Salt, phosphate and vanadate are preferred. One of these may be used alone, or two or more thereof may be used in any ratio and combination. In addition, although the kind in particular of salt is not restrict | limited, Sodium salt, potassium salt, etc. are mentioned from the high solubility to water.

  Moreover, as a precipitation production | generation agent used when precipitating the said corrosion inhibitor, what kind of thing may be used if the said corrosion inhibitor can be precipitated. Examples of such a precipitation generator include various calcium compounds such as calcium chloride, calcium bromide, calcium iodide, calcium nitrate, and calcium nitrite, and these compounds have high solubility in water. Is preferred. In addition, these may be used individually by 1 type and 2 or more types may be used by arbitrary ratios and combinations.

  Further, the method for separating the precipitate of the corrosion inhibitor and the supernatant is not limited to this in the above embodiment, but may be any method. For example, in addition to the settling tank, a separation membrane (filtration membrane) can also be used. However, in consideration of use in an environment exposed to radiation, it is preferable to use a sedimentation tank that is less susceptible to radiation and has higher durability.

  Furthermore, in the above-described embodiment, an ion exchange resin or a strong acid contact device is used to solubilize the precipitate of the corrosion inhibitor. Is not to be done. Further, the strong acid used in the strong acid contact device 110 is not limited to the sulfuric acid or nitric acid, and any strong acid can be used as long as the effects of the present invention are not significantly impaired.

  Further, for example, in the first embodiment shown in FIG. 1, the corrosion inhibitor is recovered before the cesium removing device 104 removes cesium, and the recovered corrosion inhibitor is added again to the fresh water from the fresh water tank 106. ing. However, these locations can be changed as appropriate, and as the recovery position of the corrosion inhibitor, for example, between the cesium removal device 104 and the desalination device 105, between the desalination device 105 and the concentrated water tank 107, Between the concentrated water tank 107 and the evaporative concentration apparatus 108, between the evaporative concentration apparatus 108 and the concentrated waste liquid storage tank 109, and the like are possible. Further, the position of re-addition of the corrosion inhibitor may be, for example, between the desalinator 105 and the fresh water tank 106, or between the evaporation concentrator 108 and the fresh water tank 106.

  Further, for example, in the second embodiment shown in FIG. 3, as described above, the corrosion inhibitor is recovered between the reactor pressure vessel 53 and the reactor cooling water purification device 60, and the re-addition position of the corrosion inhibitor is obtained. Is between the reactor pressure vessel 53 and the reactor cooling water purification device 60, but is not limited thereto. Specifically, for example, the recovery position of the corrosion inhibitor may be a front stage of a condensate filtration device or a condensate demineralizer. Further, the re-addition position of the corrosion inhibitor may be between the condensate demineralizer 58 and the feed water heater 59, between the feed water heater 59 and the reactor pressure vessel 53, or the like. However, the re-addition position of the corrosion inhibitor is on the downstream side of the recovery position.

  For example, in the third embodiment shown in FIG. 4, the recovery position of the corrosion inhibitor is between the reactor pressure vessel 53 and the reactor water demineralizer 62, and the re-addition position of the corrosion inhibitor is the lithium remover 63. However, the present invention is not limited to this. Specifically, the recovery position of the corrosion inhibitor can be, for example, between the reactor water demineralizer 62 and the lithium remover 63. Further, the re-addition position of the corrosion inhibitor can be set, for example, between the reactor water demineralizer 62 and the lithium remover 63. However, the re-addition position of the corrosion inhibitor is on the downstream side of the recovery position.

  Further, the reactor structure with water to be treated is not limited to those described in the above embodiments (such as stagnant water and cooling water). For example, in the first embodiment, water containing a corrosion inhibitor is supplied to the reactor pressure vessel 53, and the corrosion inhibitor is recovered from the water retained in the reactor building 51 and the turbine building 54. As long as the contained water is a nuclear reactor structure, the corrosion suppression apparatus and the corrosion suppression method of the present embodiment are suitable for any building, apparatus, means, member, or the like.

50 Nuclear power plant (reactor structure)
51 Reactor building (reactor structure)
50A Nuclear power plant 50B Nuclear power plant 53 Reactor pressure vessel (reactor structure)
54 Turbine building (reactor structure)
100 Corrosion Inhibitor 101 Reaction Tank (Reactor)
102 Sedimentation tank (separator)
103 Ion exchange resin (ionization equipment)
110 Strong acid contact device (ionization device)
200 Corrosion inhibitor 300 Corrosion inhibitor

Claims (11)

Against the reactor structure seawater containing radioactive materials is retained, and the corrosion inhibitor-containing water supplying step of supplying water containing corrosion inhibitors,
A precipitation generator is added to the seawater containing the corrosion inhibitor and the radioactive material discharged from the nuclear reactor structure to generate a precipitate of the corrosion inhibitor that can be re-dissolved in water. A precipitate generation step;
A separation step of separating the precipitate generated in the precipitate generation step from the supernatant;
An ionization step of ionizing the precipitate separated in the separation step to obtain water in which the corrosion inhibitor is dissolved;
A corrosion inhibitor addition step for adding the water obtained by dissolving the corrosion inhibitor obtained in the ionization step to the water supplied to the reactor structure in the corrosion inhibitor-containing water supply step. A feature of the method for inhibiting corrosion of a nuclear reactor structure.   The method for inhibiting corrosion of a nuclear reactor structure according to claim 1, wherein the corrosion inhibitor is at least one of an oxoacid salt and an ion constituting the oxoacid salt.   The reactor structure according to claim 2, wherein the oxo acid salt is at least one selected from the group consisting of molybdate, tungstate, phosphate and vanadate. Suppression method.   Fresh water obtained by removing the radioactive material from the seawater after the corrosion inhibitor is recovered in the precipitate generation step and desalinating the seawater after the radioactive material is removed is the corrosion inhibitor. The method for inhibiting corrosion of a nuclear reactor structure according to any one of claims 1 to 3, wherein the method is used as water to be supplied to the nuclear reactor structure in a contained water supply step. The said precipitation production | generation agent is at least 1 sort (s) chosen from the group which consists of calcium chloride, calcium bromide, calcium iodide, calcium nitrate, and calcium nitrite , The any one of Claims 1-3 characterized by the above-mentioned. The method for inhibiting corrosion of a nuclear reactor structure according to claim 1. In the ionization step, the ionization of the precipitate is performed by bringing the precipitate into contact with at least one of a hydrogen-type strongly acidic ion exchange resin and an acidic aqueous solution . The method for inhibiting corrosion of a nuclear reactor structure according to any one of the above items. A reactor for generating a precipitate of the corrosion inhibitor by being discharged from a reactor structure supplied with water containing a corrosion inhibitor and adding a precipitation generator to seawater containing the corrosion inhibitor and a radioactive substance. When,
A separator for separating the precipitate generated in the reactor from the supernatant, and supplying the separated supernatant to the reactor structure;
And a ionizer said obtaining corrosion inhibitor is dissolved water, are added to the water supplied to the obtained water to the reactor structure by ionizing the separated precipitate in the separation device An apparatus for inhibiting corrosion of a nuclear reactor structure.   8. The corrosion inhibitor for a nuclear reactor structure according to claim 7, wherein the corrosion inhibitor is at least one of an oxo acid salt and an ion constituting the oxo acid salt.   9. The corrosion of a nuclear reactor structure according to claim 8, wherein the oxo acid salt is at least one selected from the group consisting of molybdate, tungstate, phosphate and vanadate. Suppression device.   The said precipitation production | generation agent is at least 1 sort (s) chosen from the group which consists of calcium chloride, calcium bromide, calcium iodide, calcium nitrate, and calcium nitrite, The any one of Claims 7-9 characterized by the above-mentioned. The reactor structure corrosion inhibitor according to claim 1.   The said ionization apparatus is provided with at least one of a hydrogen type strong acidic ion exchange resin and the strong acid contact apparatus which makes the said precipitate contact with a strong acid, The any one of Claims 7-9 characterized by the above-mentioned. The reactor structure corrosion inhibitor according to Item 1.

Images