WO2011093305A1 - Treatment method, treatment facility and impurity-removing material for radioactive gaseous waste - Google Patents

Treatment method, treatment facility and impurity-removing material for radioactive gaseous waste Download PDF

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WO2011093305A1
WO2011093305A1 PCT/JP2011/051416 JP2011051416W WO2011093305A1 WO 2011093305 A1 WO2011093305 A1 WO 2011093305A1 JP 2011051416 W JP2011051416 W JP 2011051416W WO 2011093305 A1 WO2011093305 A1 WO 2011093305A1
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gas waste
radioactive gas
impurity
radioactive
removing material
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PCT/JP2011/051416
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French (fr)
Japanese (ja)
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周一 菅野
泰雄 吉井
秀宏 飯塚
高志 西
元浩 会沢
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日立Ｇｅニュークリア・エナジー株式会社
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Priority to JP2011551864A priority Critical patent/JP5564519B2/en
Publication of WO2011093305A1 publication Critical patent/WO2011093305A1/en

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/02—Treating gases

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  • the present invention relates to a treatment method and treatment equipment for radioactive gas waste discharged from a nuclear reactor at a nuclear power plant. Moreover, it is related with the impurity removal material which removes the impurity in a radioactive gas waste.
  • reactor water in a nuclear reactor is partially decomposed into hydrogen and oxygen by radiation decomposition.
  • the hydrogen and oxygen are discharged from the reactor as radioactive gas waste together with the water vapor evaporated from the reactor water.
  • the water vapor containing hydrogen and oxygen passes through a recombination catalyst provided in a recombination apparatus at the rear stage of the nuclear reactor, and the hydrogen and oxygen recombine with H 2 O on the catalyst.
  • air is added between the nuclear reactor and the recombination apparatus.
  • the recombination catalyst an alumina catalyst supporting Pt and Pd is used as the recombination catalyst.
  • Patent Document 1 discloses a technique for supplementing an organosilicon complex in a gasoline fraction.
  • a material in which an alkali metal is supported on alumina is used as a material for removing the impurity.
  • radioactive gas waste discharged from nuclear reactors contains impurities depending on the operating conditions of the equipment inside the reactor and upstream of the reactor, and these impurities poison the recombination catalyst of the recombination equipment.
  • impurities depending on the operating conditions of the equipment inside the reactor and upstream of the reactor, and these impurities poison the recombination catalyst of the recombination equipment.
  • a recombination catalyst is poisoned by a silicon compound such as siloxane and the performance is lowered, and H 2 remains in a high concentration in exhaust gas discharged from the recombiner.
  • the present invention has been made in order to solve the above-described problems, and is intended to provide a radioactive gas waste capable of operating a nuclear power plant without causing an abnormal increase in H 2 concentration in exhaust gas from a recombiner.
  • a processing method, processing equipment, and an impurity removing material are provided.
  • the radioactive gas waste processing method according to the present invention basically has the following characteristics.
  • the impurities contained in the radioactive gas waste are: A step of removing by contacting with an impurity removing material containing at least one of ZrO 2 , mesoporous silica, and activated carbon; and after removing the impurities, contacting the radioactive gas waste with the catalyst to form the hydrogen and the hydrogen And recombining with oxygen.
  • An impurity removing material according to the present invention is an impurity removing material that removes impurities contained in radioactive gas waste discharged from a nuclear reactor at a nuclear power plant, and includes at least one of ZrO 2 , mesoporous silica, and activated carbon. Including is a basic feature.
  • the radioactive gas waste treatment facility according to the present invention basically has the following characteristics.
  • the recombination An exhaust gas preheater that heats the radioactive gas waste at the front stage of the vessel, and an impurity removing material that includes at least one of ZrO 2 , mesoporous silica, and activated carbon between the exhaust gas preheater and the recombiner. And a filled impurity removal layer.
  • the radioactive gas waste treatment facility according to the present invention can basically have the following characteristics.
  • the recombination The vessel includes an impurity removal layer filled with an impurity removal material including at least one of ZrO 2 , mesoporous silica, and activated carbon, and the impurity removal layer and the recombination catalyst layer are configured such that the radioactive gas waste is regenerated by the recycle catalyst layer. It is arranged to pass through the coupler in this order.
  • the nuclear power plant can be safely operated without increasing the H 2 concentration in the exhaust gas at the outlet of the recombiner. Can do.
  • the impurities can be removed from the radioactive gas waste by bringing the impurities into contact with the impurity removing material under appropriate conditions before the radioactive gas waste flows into the recombination catalyst layer. It was found that the catalyst performance degradation can be suppressed.
  • the radioactive gas waste processing method, the processing equipment, and the impurity removing material according to the present invention can be used for various catalysts without changing the recombination catalyst.
  • the impurity removing material As the impurity removing material, a material that can remove impurities even in a high-concentration water vapor atmosphere is optimal.
  • the composition of the radioactive gas waste processed by the recombiner is largely different from that of a normal processing gas because water vapor accounts for about 98 vol%. The remaining few percent is radioactively decomposed H 2 and O 2 , and N 2 in the air added before the recombiner. For this reason, there is an optimum material for removing impurities, and otherwise, the catalyst performance is lowered.
  • Specific examples of the impurity removing material include those containing at least one of ZrO 2 , mesoporous silica, and activated carbon. In particular, ZrO 2 and mesoporous silica are desirable because they do not contain carbon.
  • the operating temperature is preferably 100 to 500 ° C. When the temperature is 100 ° C. or lower, water vapor in the radioactive gas waste is condensed, so that the predetermined performance is not exhibited.
  • the upper limit of the use temperature depends on the system to be used, but it is desirable to use it at 500 ° C. or lower in order to heat the entire radioactive gas waste.
  • the temperature is 200 ° C. or lower. It is desirable to use it.
  • the temperature of the radioactive gas waste flowing into the recombination catalyst becomes high, and the recombination catalyst may deteriorate due to heat generated by the recombination reaction.
  • the impurity removing material needs to pay attention to radiation of recombination reaction heat on the recombination catalyst.
  • the temperature of the impurity removing material increases due to radiation, the trapped impurities may be desorbed.
  • the impurity removing material when installed outside the recombiner, it can be used below the heat resistance temperature of the impurity removing material. However, in order to heat the whole radioactive gaseous waste, it is desirable to use it at 500 degrees C or less. When using at 200 degreeC or more, it is desirable to install coolers, such as a heat exchanger, between an impurity removal layer and a recombination catalyst layer, before making a radioactive waste flow into a recombiner.
  • coolers such as a heat exchanger
  • siloxane when used as the impurity removing material, siloxane can be decomposed when used at 180 ° C. or higher. If water vapor is present, it can be hydrolyzed.
  • the decomposition reaction of C 10 H 30 O 5 Si 5 (D5), which is a kind of siloxane, is represented by the following formula.
  • the recombination catalyst is desirably used at 600 ° C or lower, and more preferably at 500 ° C or lower.
  • the sintering of the catalytically active component is easily promoted, and the performance is deteriorated.
  • the exotherm due to the recombination reaction varies depending on the amount of H 2 flowing into the recombination catalyst.
  • the temperature of the impurity removing material can be set so that the use temperature of the recombination catalyst is 600 ° C. or less.
  • the impurity removing material is installed outside the recombiner, it can be used at 200 ° C. or higher. In that case, it is desirable to install a cooler such as a heat exchanger between the impurity removal layer and the recombination catalyst layer before the radioactive waste flows into the recombiner.
  • a material that exhibits decomposition characteristics after trapping when the operating temperature is raised needs to have an acid point as a chemical property. Moreover, it is desirable that many acid sites exist per unit surface area.
  • the aforementioned ZrO 2 is 0.0064 ⁇ mol / m 2 , Materials with higher values are desirable. Further, TiO 2 is less than 0.0051 ⁇ mol / m 2 and ZrO 2, is believed to show similar effects.
  • ZSM-5 is 0.0017 mol / m 2, but up to this level, it is considered that the same effect can be obtained depending on the operating temperature. Other than that of 0.0017 mol / m 2 or more is activated alumina. A second component may be added to these to improve the acid point amount. In addition, said acid point amount was measured as follows.
  • the acid point amount of the impurity removing material was measured using a metal exposure analyzer (BELCAT-A manufactured by Nippon Bell Co., Ltd.).
  • a metal exposure analyzer BELCAT-A manufactured by Nippon Bell Co., Ltd.
  • particles having a diameter of 0.5 to 1.0 mm were used in the form of powder in a mortar.
  • the sample amount is 0.05 g.
  • the measurement includes a pretreatment process, an NH 3 adsorption process, and a temperature programmed desorption process.
  • the pretreatment step He was circulated as a treatment gas at 50 ml / min, the temperature was raised from room temperature to 500 ° C. at 10 ° C./min, and held at 500 ° C. for 60 min. Thereafter, the temperature was lowered to 100 degrees by natural cooling.
  • Impurity-removing materials are used to reduce poisoning caused by siloxane as a recombination catalyst in nuclear power plants, suppress insulation failure due to adhesion of siloxane to electrical relays, suppress haze caused by adhesion of siloxane to optical products, and repel paint due to adhesion of siloxane to the coating surface Can be used for suppression.
  • Siloxane is also contained in dry cleaning chemicals, shampoos, cosmetics, silicone tubes and silicone grease, and siloxane-containing substances may be generated even in the environment where these are used.
  • An impurity removing material can be used.
  • Fig. 7 shows the processing flow diagram of the system.
  • the fluid containing siloxane or the fluid passing through the siloxane generation source 100 is allowed to flow into the device 102 that is not desired to be poisoned by siloxane, the fluid is passed through the impurity removal layer 101 containing the impurity removing material and then poisoned by siloxane. It flows into the apparatus 102 which does not want to be discharged.
  • Siloxane is a compound in which a reference structure of —OSi (CH 3 ) 2 — is continuously bonded and finally becomes a ring.
  • the size of the compound is determined by the number of reference structures. For example, in the case of describing D5, the above-described reference structure is five cyclic compounds.
  • compounds of about D3 to D8 are targeted, but in the present invention, compounds having two or less reference structures can also be handled as impurities. It is presumed that a compound having two or less reference structures cannot form a cyclic structure, and thus has a linear structure and has a terminal —OH.
  • Impurities other than silicon compounds include hydrocarbons, sulfuric acid compounds, chlorine compounds, and fluorine compounds.
  • the test was conducted with a silicon compound as a representative example, but the present invention has the same effect with respect to other impurities.
  • the impurity removing material preferably has a large specific surface area.
  • the impurity removing material has a structure having micropores and mesopores, the specific surface area becomes large, and the amount of impurities to be captured increases.
  • an impurity removing material such as ZrO 2 may be supported on a material having a high specific surface area such as alumina, TiO 2 , zeolite, or mesoporous silica. It may be combined with these components and converted into a composite oxide to increase the specific surface area.
  • the siloxane trapping performance is improved.
  • hydrophilic components such as Ni, Zn, W, Fe, Co, Ce, and Ti may be supported.
  • hydrophobic components such as organic groups, such as F and a methyl group. Since siloxane has a hydrophilic Si group and a hydrophobic organic group, increasing the hydrophilicity improves the Si group capturing performance, and improving the hydrophobicity improves the organic group capturing performance. You may carry
  • FIG. 5 shows an exhaust gas treatment flow from the nuclear reactor.
  • Water vapor including H 2 and O 2 ) contained in the radioactive gas waste generated in the nuclear reactor is used to turn the turbine.
  • the radioactive gas waste after turning the turbine is heated to a predetermined temperature by the exhaust gas preheater and introduced into the recombiner.
  • H 2 and O 2 are combined and changed to H 2 O (water vapor).
  • the steam is returned to the water by the condenser, and the moisture is removed by the dehumidifying cooler.
  • ZrO 2 material 1
  • mesoporous silica material 2
  • activated carbon material 3
  • TiO 2 Comparative 1
  • ZSM-5 Comparative 2
  • ZrO 2 Zirconyl nitrate dihydrate (commercial product, Wako Pure Chemical Industries, Ltd. reagent) was calcined in the atmosphere at 500 ° C. for 2 hours to prepare ZrO 2 .
  • the fired powder was press-molded at 500 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
  • Mesoporous silica (commercial product, manufactured by Zude Chemie Catalyst Co., Ltd.) was dried at 120 ° C. for 2 hours. The dried powder was press-molded at 200 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
  • Activated carbon activated carbon (commercially available product, spherical white DX7-3 (0.5-3.0 mm diameter) manufactured by Takeda Pharmaceutical Co., Ltd.) was dried at 120 ° C. for 2 hours. After drying, the mixture was crushed with a mortar and sized to 0.5 to 1.0 mm.
  • TiO 2 TiO 2 having a particle diameter of 2 to 4 mm (commercial product, CS-200S-24 manufactured by Sakai Chemical Industry Co., Ltd.) was crushed with a mortar and sized to 0.5 to 1.0 mm.
  • ZSM-5 ZSM-5 (commercial product, H-MFI-240 manufactured by Zude Chemie Catalysts Co., Ltd.) was press-molded at 500 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
  • siloxane was added as an impurity to the reaction gas, and the effect of the impurity removing material prepared in Example 1 was examined. Specifically, the reaction gas to which siloxane was added was introduced into a reaction tube having an impurity removal layer and a recombination catalyst layer, and the H 2 concentration at the outlet of the reaction tube was measured. The impurity removal layer of the reaction tube is filled with an impurity removal material, and the recombination catalyst layer is filled with a recombination catalyst.
  • reaction gas water 2.4 ml / min is vaporized into water vapor by a steam generator, H 2 97 ml / min and O 2 48.3 ml / min are mixed, and air is added 17.7 ml / min. Was used.
  • This reaction gas was allowed to flow at 150 ° C. into the recombination catalyst layer.
  • the space velocity represented by (Equation 1) was 109,400 h ⁇ 1
  • linear velocity represented by (Equation 2) was 0.297 m / s.
  • the reason why the metal mesh is laid is to prevent the impurity removing material from falling to the lower part (downstream of the flow of the reaction gas).
  • the reaction gas introduced into the reaction tube first passes through the impurity removal layer, then the recombination catalyst layer, and reaches the outlet.
  • the H 2 concentration in the reaction gas that has passed through the recombination catalyst layer is determined by using a PDD (Pulsed Discharge Detector) gas chromatograph analyzer (GC Science Co., Ltd. GC) after condensing water vapor into water in an ice-cooled cooling bath. -4000) and measured.
  • PDD Pulsed Discharge Detector
  • HID Helium Ionization Detector
  • 100 ⁇ l of sample gas (reactive gas that passed through the recombination catalyst layer) was sucked with a pump.
  • the gas inlet temperature of the gas chromatograph was room temperature, the detector temperature was 150 ° C., and the oven temperature was 50 ° C.
  • the column had an outer diameter of 1/8 inch ⁇ ⁇ length of 2 m, and Molecular Sieve 13X-S (60-80 mesh) was used as a packing material.
  • He was allowed to flow at 20 ml / min. Further, He was allowed to flow at 30 ml / min as a discharge gas.
  • the impurities are heated to 150 ° C. and introduced into a reaction tube filled with an impurity removing material and a recombination catalyst, and when the H 2 concentration at the outlet of the reaction tube (outlet H 2 concentration) becomes stable,
  • One type of D5 was added dropwise from the top of the reaction tube at 2.5 ⁇ 10 ⁇ 8 liter / min.
  • the outlet concentration of H 2 to be stable for each test differs slightly with respect to the outlet concentration of H 2 immediately before the addition of D5, was compared outlet concentration of H 2 was increased after addition of D5.
  • FIG. 1 is a diagram comparing outlet H 2 concentrations 35 minutes and 60 minutes after adding D5 to the reaction gas.
  • ZrO 2 material 1
  • MPS mesoporous silica
  • activated carbon material 3
  • TiO 2 material 3
  • ZrO 2 was charged with 1.8 ml (2.51 g) in the impurity removal layer on the upper part of the recombination catalyst layer (upstream side of the reaction gas flow).
  • the outlet H 2 concentration when ZrO 2 was filled as an impurity removing material was almost the same as when only the recombination catalyst was filled after 35 minutes, but the increase was clearly suppressed after 60 minutes.
  • MPS mesoporous silica
  • the outlet gas temperature measured at the outlet of the recombination catalyst layer under test was 285 ° C. at the maximum. This is because the recombination reaction proceeds on the recombination catalyst and heat is generated.
  • the difference in the removal performance of ZrO 2 and TiO 2 is due to the difference in specific surface area and the amount of solid acid.
  • D5 is adsorbed on the surface of the removal material, and the amount of adsorption is estimated to be governed by the amount of solid acid.
  • the solid acid point is a point where an acid-base reaction proceeds on the surface, and the solid acid amount per unit specific surface area is considered to determine the adsorption rate.
  • the solid acid amounts of ZrO 2 and TiO 2 were examined by NH 3 adsorption method.
  • the NH 3 adsorption method is a method in which NH 3 is adsorbed on a catalyst, and then the desorption temperature and desorption amount of adsorbed NH 3 are measured while raising the temperature. The adsorption power of NH 3 can be seen from the desorption temperature.
  • a predetermined amount of sample (ZrO 2 or TiO 2 ) was filled in the reaction tube, and pretreatment was performed.
  • the water adsorbed on the catalyst surface was removed by raising the temperature to 450 ° C. under a flow of He gas and maintaining the temperature at 450 ° C. for 30 minutes.
  • Adsorption treatment of NH 3 was introduced and NH 3 was diluted to 9.5Vol% with He gas into the reaction tube is adsorbed on the sample.
  • the adsorption temperature was 100 ° C.
  • the concentration of unadsorbed gas flowing out in a pulse manner from the reaction tube outlet was quantified, and it was judged that the adsorption was completed when this concentration became constant.
  • NH 3 was heated and desorbed by heating to 700 ° C. in a He stream after completion of adsorption, and the amount of NH 3 desorbed was measured.
  • the NH 3 concentration at the outlet of the reaction tube was measured with a TCD gas chromatograph.
  • the solid acid amount of ZrO 2 was 0.015 mol / m 2
  • the solid acid amount of TiO 2 was 0.012 mol / m 2 . From this, it was found that the impurity removing material requires a solid acid amount of at least 0.012 mol / m 2 or more. It is estimated that even if the amount of solid acid becomes too large, the removal performance is limited due to steric hindrance between adsorbed impurities.
  • ZSM-5 had a large specific surface area and a large amount of solid acid, but its performance was low. This is thought to be due to the low hydrothermal resistance of ZSM-5. When used in an atmosphere with a lot of water vapor as in this embodiment, it is necessary to make the surface hydrophobic and to sufficiently reduce impurities inside ZSM-5 containing structurally unstable Si.
  • FIG. 2 is a diagram showing a change with time of the outlet H 2 concentration when the amount of ZrO 2 in the impurity removal layer is increased to 2.7 ml (3.77 g).
  • the results when D5 is not added to the reaction gas and only the recombination catalyst is filled into the reaction tube and when only D5 is added to the reaction gas and the reaction tube is filled with only the recombination catalyst are also shown. It was.
  • the amount of ZrO 2 filled in the impurity removal layer is larger in the case of FIG. 2, and the increase in the outlet H 2 concentration is smaller. From this, it can be seen that increasing the filling amount of ZrO 2 further suppresses the increase in the outlet H 2 concentration.
  • FIG. 3 is an example of a cross-sectional view of a recombiner that recombines hydrogen and oxygen in water vapor contained in radioactive gas waste with a catalyst.
  • the recombiner 3 includes a recombination catalyst layer 2 filled with a recombination catalyst, and an impurity removal layer 5 filled with an impurity removal material, and the radioactive gas waste 1 flows in.
  • the impurity removal layer 5 is installed in the recombiner 3 on the upstream side of the flow of the radioactive gas waste 1 when viewed from the recombination catalyst layer 2.
  • the recombiner 3 includes a heating facility 4. For the heating equipment 4, for example, a heater is used.
  • the impurity removal layer 5 is filled in the cartridge 6, and the cartridge 6 is held by the cartridge support 7.
  • the cartridge support 7 is welded inside the recombiner 3.
  • the impurity removal layer 5 is installed in the recombiner 3 where the temperature is 100 to 200 ° C.
  • the temperature of the radioactive gas waste 1 is controlled to be 100 to 200 ° C. by the heating equipment 4. Due to the heated radioactive gas waste 1, the temperature of the impurity removal layer 5 can be kept within the range of 100 to 200 ° C. even if the temperature of the recombination catalyst layer 2 rises.
  • the impurity removing material is installed in a part where the temperature is lower than 100 ° C., the water vapor is condensed and the predetermined performance cannot be obtained. Moreover, when it exceeds 200 degreeC, the temperature control of the recombination catalyst layer 2 will become difficult. When the inlet temperature of the recombination catalyst layer 2 exceeds 200 ° C., the temperature inside the catalyst rises due to the recombination reaction, causing deterioration of the catalyst.
  • the radioactive gas waste 1 that has passed through the impurity removal layer 5 flows into the recombination catalyst layer 2 at 140 to 160 ° C. desirable.
  • the shape of the impurity removing material can be molded into a granular shape, a columnar shape, a pellet shape, or the like.
  • the ceramic honeycomb surface may be coated, or the metal wire surface may be coated.
  • the impurity removal layer 5 is preferably filled in a cartridge 6 which is a porous container.
  • a cartridge 6 which is a porous container.
  • a cartridge support may be placed on the recombination catalyst layer 2 and held.
  • FIG. 4 is a diagram showing another installation example of the impurity removing material, and shows an example of a cross-sectional view of the recombiner and the impurity removing layer.
  • FIG. 4 shows a case where the impurity removing material is installed outside the recombiner and before the recombiner.
  • An exhaust gas preheater (see FIG. 5) is usually arranged in the front stage of the recombiner 3, but an impurity removal layer 5 filled with an impurity removal material is installed between the exhaust gas preheater and the recombiner 3. May be.
  • the recombiner 3 includes only the recombination catalyst layer 2 filled with the recombination catalyst.
  • the impurity removal layer 5 is filled in the cartridge 6. The radioactive gas waste 1 passes through the impurity removal layer 5 and flows into the recombiner 3.
  • a heating facility 4 such as a heater is provided around the impurity removal layer 5.
  • the radioactive gaseous waste 1 can be heated to 100 to 200 ° C. by the heating equipment 4 and the temperature of the impurity removal layer 5 can be kept within the range of 100 to 200 ° C. For example, when the temperature of the impurity removal layer 5 is low, it can be heated by the heating equipment 4 and raised to a predetermined temperature.
  • high temperature exhaust gas burned with fuel may be mixed with radioactive gas waste.
  • the impurity removal layer 5 when the structure in which the impurity removal layer 5 is installed in the previous stage of the recombiner 3, two or more impurity removal layers 5 can be arranged.
  • the impurity removal layer 5 is installed inside the recombiner 3, and the number of installation is limited.
  • two or more impurity removal layers 5 are arranged, there is an advantage that the operation can be performed while operating the radioactive gas waste treatment facility even in an emergency or material exchange.
  • the recombination catalyst of Example 1 was removed, siloxanes before and after the material 1 (ZrO 2 ) were analyzed, and the effect of the impurity removing material was examined.
  • the reaction gas to which siloxane was added was introduced into a reaction tube having an impurity removal layer, and the concentration of siloxanes at the outlet of the reaction tube was measured.
  • the impurity removal layer of the reaction tube was filled with material 1 as an impurity removal material. Further, the same reaction gas was passed through a reaction tube having no impurity removal layer, and the concentration of siloxanes at the inlet of the reaction tube was measured.
  • the reaction gas was vaporized with 0.8 ml / min of water using a steam generator, and added with 7.5 ml / min of air to supply water vapor.
  • 40 ml / min of H 2 and 20.3 ml / min of O 2 were mixed and helium was further added at 2027.5 ml / min. Part of helium was used to supply D5, a kind of siloxane.
  • the reaction gas was allowed to flow into the impurity removal layer at 92 to 289 ° C.
  • the amount of the impurity removing material was 2.7 ml (3.76 g).
  • the reaction tube was filled with material 1 at the same position as in Example 1.
  • the recombination catalyst layer portion was filled with alumina wool.
  • the reaction gas introduced into the reaction tube passes through the impurity removal layer and reaches the outlet.
  • the H 2 concentration in the reaction gas that passed through the recombination catalyst layer was measured in the same manner as in Example 1.
  • the siloxanes were measured by collecting gas after condensing water vapor into water in an ice-cooled cooling bath and measuring with a mass spectrometer.
  • FIG. 6 is a graph showing the temperature of the material 1 (impurity removing material) and the D5 reduction rate 30 minutes after adding D5 to the reaction gas.
  • the D5 reduction rate is as low as 25.0% when the temperature of the material 1 is 92 ° C. (corresponding to the reaction gas temperature of 150 ° C. in Example 1), but is 86.8% at 180 ° C., 91.8% at 220 ° C. It was found to be 96.4% at 257 ° C. and 99.6% at 289 ° C.
  • methane CH 4
  • Degradation of D5 was suggested. Therefore, the effect of the material 1 is considered to decompose the adsorbed siloxane.
  • the present invention can be used for the treatment of radioactive gas waste at nuclear power plants.

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  • Engineering & Computer Science (AREA)
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  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

Impurities contained in a radioactive gaseous waste that is discharged from a nuclear reactor can be removed to prevent the deterioration in performance of a recombination catalyst in a recombination device. Disclosed is a radioactive gaseous waste treatment method in which hydrogen and oxygen in water vapor that is contained in a radioactive gaseous waste discharged from a nuclear reactor in a nuclear power plant are recombined with each other by utilizing a catalyst. The method comprises the steps of: bringing impurities contained in a radioactive gaseous waste (1) into contact with an impurity-removing material (5) containing at least one material selected from ZrO2, mesoporous silica and activated carbon to remove the impurities; and, subsequent to the removal of the impurities, bringing the radioactive gaseous waste into contact with a catalyst (2) to cause the recombination of hydrogen with oxygen.

Description

放射性気体廃棄物の処理方法、処理設備、及び不純物除去材Radioactive gas waste treatment method, treatment facility, and impurity removal material
　本発明は、原子力発電所で原子炉から排出される放射性気体廃棄物の処理方法及び処理設備に関する。また、放射性気体廃棄物中の不純物を除去する不純物除去材に関する。 The present invention relates to a treatment method and treatment equipment for radioactive gas waste discharged from a nuclear reactor at a nuclear power plant. Moreover, it is related with the impurity removal material which removes the impurity in a radioactive gas waste.
　原子力発電プラントにおいて、原子炉内の炉水は、放射線分解により、一部が水素と酸素に分解する。この水素と酸素は、炉水が気化した水蒸気とともに、放射性気体廃棄物として原子炉から排出される。水素と酸素を含む水蒸気は、原子炉の後段の再結合装置に設けられた再結合触媒を通り、水素と酸素は、触媒上でＨ２Ｏに再結合する。触媒上での再結合反応を効率良く行わせるために、原子炉と再結合装置との間で空気を添加している。再結合触媒としては、Ｐｔ、Ｐｄを担持したアルミナ触媒が使用されている。 In a nuclear power plant, reactor water in a nuclear reactor is partially decomposed into hydrogen and oxygen by radiation decomposition. The hydrogen and oxygen are discharged from the reactor as radioactive gas waste together with the water vapor evaporated from the reactor water. The water vapor containing hydrogen and oxygen passes through a recombination catalyst provided in a recombination apparatus at the rear stage of the nuclear reactor, and the hydrogen and oxygen recombine with H 2 O on the catalyst. In order to efficiently perform the recombination reaction on the catalyst, air is added between the nuclear reactor and the recombination apparatus. As the recombination catalyst, an alumina catalyst supporting Pt and Pd is used.
　一方、ガソリン留分中の有機シリコン複合体を補足する技術が、特許文献１に開示されている。これは、有機ケイ素化合物がガソリン留分中に不純物として含まれる場合に、この不純物の除去材として、アルミナにアルカリ系金属を担持した材料を用いるというものである。 On the other hand, Patent Document 1 discloses a technique for supplementing an organosilicon complex in a gasoline fraction. In this method, when an organosilicon compound is contained as an impurity in a gasoline fraction, a material in which an alkali metal is supported on alumina is used as a material for removing the impurity.
特開２００８－１０１２０７号公報JP 2008-101207 A
　原子力発電プラントにおいて、原子炉から排出される放射性気体廃棄物には、原子炉内や原子炉より上流の機器の運転条件により不純物が含まれ、この不純物により再結合装置の再結合触媒が被毒されることが判明した。近年、特に、シロキサンなどのケイ素化合物により再結合触媒が被毒して性能が低下し、再結合器から排出される排ガス中にＨ２が高濃度で残存することがわかった。 In nuclear power plants, radioactive gas waste discharged from nuclear reactors contains impurities depending on the operating conditions of the equipment inside the reactor and upstream of the reactor, and these impurities poison the recombination catalyst of the recombination equipment. Turned out to be. In recent years, it has been found that, particularly, a recombination catalyst is poisoned by a silicon compound such as siloxane and the performance is lowered, and H 2 remains in a high concentration in exhaust gas discharged from the recombiner.
　以前は、再結合器より上流側の設備には異なる材料が使用されていたため、再結合触媒の被毒を考慮する必要がなかった。従って、不純物の除去については考慮されていない。 Previously, different materials were used for the equipment upstream of the recombiner, so there was no need to consider poisoning of the recombination catalyst. Therefore, removal of impurities is not considered.
　そこで、排ガス中のＨ２濃度の上昇を防ぎ、原子力発電プラントを安全に運転するためには、放射性気体廃棄物に含まれる不純物を除去し、再結合装置の再結合触媒の被毒と性能低下を防止することが新たな課題となっている。 Therefore, in order to prevent an increase in H 2 concentration in the exhaust gas and to safely operate the nuclear power plant, impurities contained in the radioactive gas waste are removed, and the recombination catalyst poisoning and performance degradation of the recombination equipment Prevention has become a new issue.
　本発明は、上記課題を解決するためになされたものであり、再結合器からの排出ガス中のＨ２濃度の異常上昇を起こさずに原子力発電プラントを運転することができる放射性気体廃棄物の処理方法、処理設備、及び不純物除去材を提供する。 The present invention has been made in order to solve the above-described problems, and is intended to provide a radioactive gas waste capable of operating a nuclear power plant without causing an abnormal increase in H 2 concentration in exhaust gas from a recombiner. A processing method, processing equipment, and an impurity removing material are provided.
　上記課題を解決するための手段として、本発明による放射性気体廃棄物処理方法は、基本的には、以下のような特徴を有する。 As a means for solving the above problems, the radioactive gas waste processing method according to the present invention basically has the following characteristics.
　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを触媒にて再結合させる放射性気体廃棄物処理方法において、前記放射性気体廃棄物に含まれる不純物を、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材と接触させて除去する工程と、前記不純物を除去した後、前記放射性気体廃棄物を前記触媒と接触させて前記水素と前記酸素とを再結合させる工程とを備える。 In the radioactive gas waste treatment method of recombining hydrogen and oxygen in water vapor contained in the radioactive gas waste discharged from the nuclear reactor at the nuclear power plant with a catalyst, the impurities contained in the radioactive gas waste are: A step of removing by contacting with an impurity removing material containing at least one of ZrO 2 , mesoporous silica, and activated carbon; and after removing the impurities, contacting the radioactive gas waste with the catalyst to form the hydrogen and the hydrogen And recombining with oxygen.
　本発明による不純物除去材は、原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる不純物を除去する不純物除去材であって、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含むことを基本的な特徴とする。 An impurity removing material according to the present invention is an impurity removing material that removes impurities contained in radioactive gas waste discharged from a nuclear reactor at a nuclear power plant, and includes at least one of ZrO 2 , mesoporous silica, and activated carbon. Including is a basic feature.
　本発明による放射性気体廃棄物処理設備は、基本的には、以下のような特徴を有する。 The radioactive gas waste treatment facility according to the present invention basically has the following characteristics.
　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを再結合させる再結合触媒層を有する再結合器を備える放射性気体廃棄物処理設備において、前記再結合器の前段で前記放射性気体廃棄物を加熱する排ガス予熱器と、前記排ガス予熱器と前記再結合器との間に、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材を充填した不純物除去層とを備える。 In the radioactive gas waste treatment facility comprising a recombiner having a recombination catalyst layer for recombining hydrogen and oxygen in water vapor contained in the radioactive gas waste discharged from a nuclear reactor at a nuclear power plant, the recombination An exhaust gas preheater that heats the radioactive gas waste at the front stage of the vessel, and an impurity removing material that includes at least one of ZrO 2 , mesoporous silica, and activated carbon between the exhaust gas preheater and the recombiner. And a filled impurity removal layer.
　また、本発明による放射性気体廃棄物処理設備は、基本的には、以下のような特徴を有することもできる。 Also, the radioactive gas waste treatment facility according to the present invention can basically have the following characteristics.
　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを再結合させる再結合触媒層を有する再結合器を備える放射性気体廃棄物処理設備において、前記再結合器は、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材を充填した不純物除去層を備え、前記不純物除去層と前記再結合触媒層は、前記放射性気体廃棄物が前記再結合器の中をこの順で通過するように配置される。 In the radioactive gas waste treatment facility comprising a recombiner having a recombination catalyst layer for recombining hydrogen and oxygen in water vapor contained in the radioactive gas waste discharged from a nuclear reactor at a nuclear power plant, the recombination The vessel includes an impurity removal layer filled with an impurity removal material including at least one of ZrO 2 , mesoporous silica, and activated carbon, and the impurity removal layer and the recombination catalyst layer are configured such that the radioactive gas waste is regenerated by the recycle catalyst layer. It is arranged to pass through the coupler in this order.
　本発明により、原子炉から排出される放射性気体廃棄物中に不純物が含まれていても、再結合器出口における排ガス中のＨ２濃度が上昇することなく、安全に原子力発電プラントを運転することができる。 According to the present invention, even if impurities are contained in the radioactive gas waste discharged from the nuclear reactor, the nuclear power plant can be safely operated without increasing the H 2 concentration in the exhaust gas at the outlet of the recombiner. Can do.
本発明による不純物除去材の性能を示すために、反応管の出口Ｈ２濃度を比較した図である。In order to show the performance of the impurity removing material according to the present invention, it is a diagram comparing the outlet H 2 concentration of the reaction tube. 不純物除去材の量を増やした場合の、反応管の出口Ｈ２濃度の経時変化を示す図である。In the case of increasing the amount of impurity removal member is a diagram showing changes with time of the outlet concentration of H 2 in the reaction tube. 本発明による放射性気体廃棄物の処理設備における不純物除去材の設置例を示す、再結合器の断面図である。It is sectional drawing of the recombiner which shows the example of installation of the impurity removal material in the processing facility of the radioactive gas waste by this invention. 本発明による放射性気体廃棄物の処理設備における不純物除去材の別の設置例を示す、再結合器と不純物除去層の断面図である。It is sectional drawing of a recombiner and an impurity removal layer which shows another installation example of the impurity removal material in the processing facility of the radioactive gas waste by this invention. 原子炉からの排ガス処理フローを示す図である。It is a figure which shows the waste gas treatment flow from a nuclear reactor. 本発明による不純物除去材の性能を示すために、不純物除去材の温度とＤ５減少率との関係を示した図である。In order to show the performance of the impurity removal material by this invention, it is the figure which showed the relationship between the temperature of an impurity removal material, and D5 reduction | decrease rate. シロキサン含有流体の処理フローを示す図である。It is a figure which shows the processing flow of a siloxane containing fluid.
　水蒸気を主成分とする放射性気体廃棄物（排ガス）中に含まれる不純物が再結合器の再結合触媒層に流入し、再結合触媒を被毒すると、再結合器から排出される排ガス中にＨ２が高濃度で残存する。原子力発電プラントを安全に運転するためには、排ガス中のＨ２濃度の上昇を防ぐ必要がある。このため、不純物の触媒被毒成分が再結合触媒層に流入する前に、不純物を放射性気体廃棄物中から除去する必要がある。 When impurities contained in radioactive gas waste (exhaust gas) mainly composed of water vapor flow into the recombination catalyst layer of the recombiner and poison the recombination catalyst, H is contained in the exhaust gas discharged from the recombiner. 2 remains at a high concentration. In order to operate a nuclear power plant safely, it is necessary to prevent an increase in H 2 concentration in the exhaust gas. For this reason, it is necessary to remove impurities from the radioactive gas waste before the catalyst poisoning component of impurities flows into the recombination catalyst layer.
　詳細に検討した結果、放射性気体廃棄物が再結合触媒層に流入する前段で、不純物を不純物除去材と適切な条件で接触させることで、不純物を放射性気体廃棄物中から除去することができ、触媒の性能低下を抑制することができることがわかった。本発明による放射性気体廃棄物の処理方法、処理設備、及び不純物除去材は、再結合触媒を変えることなく、種々の触媒に対しても使用できる。 As a result of detailed examination, the impurities can be removed from the radioactive gas waste by bringing the impurities into contact with the impurity removing material under appropriate conditions before the radioactive gas waste flows into the recombination catalyst layer. It was found that the catalyst performance degradation can be suppressed. The radioactive gas waste processing method, the processing equipment, and the impurity removing material according to the present invention can be used for various catalysts without changing the recombination catalyst.
　不純物除去材としては、高濃度水蒸気雰囲気下でも不純物を除去できるものが最適である。再結合器で処理する放射性気体廃棄物の組成は、水蒸気が約９８ｖｏｌ％と大半を占め、通常の処理ガスとは大きく異なる。残りの数％は、放射能で分解されたＨ２とＯ２、及び再結合器の前段で添加した空気中のＮ２などである。このため、不純物除去材としては最適なものがあり、それ以外では逆に触媒性能を低下させる。具体的な不純物除去材の例としては、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含むものが挙げられる。特に、ＺｒＯ２とメソポーラスシリカは、炭素を含まないため望ましい。 As the impurity removing material, a material that can remove impurities even in a high-concentration water vapor atmosphere is optimal. The composition of the radioactive gas waste processed by the recombiner is largely different from that of a normal processing gas because water vapor accounts for about 98 vol%. The remaining few percent is radioactively decomposed H 2 and O 2 , and N 2 in the air added before the recombiner. For this reason, there is an optimum material for removing impurities, and otherwise, the catalyst performance is lowered. Specific examples of the impurity removing material include those containing at least one of ZrO 2 , mesoporous silica, and activated carbon. In particular, ZrO 2 and mesoporous silica are desirable because they do not contain carbon.
　不純物除去材は、適切な温度で使用することが望ましい。運転温度としては、１００℃～５００℃の温度域で使用するのが望ましい。１００℃以下とすると、放射性気体廃棄物中の水蒸気が凝縮するため、所定性能を発揮しない。使用温度の上限は、使用するシステムに依存するが、放射性気体廃棄物全体を加熱するため、５００℃以下で使用するのが望ましい。 It is desirable to use the impurity removal material at an appropriate temperature. The operating temperature is preferably 100 to 500 ° C. When the temperature is 100 ° C. or lower, water vapor in the radioactive gas waste is condensed, so that the predetermined performance is not exhibited. The upper limit of the use temperature depends on the system to be used, but it is desirable to use it at 500 ° C. or lower in order to heat the entire radioactive gas waste.
　不純物除去材として、活性炭またはメソポーラスシリカを、再結合器内の再結合触媒層の上部（再結合触媒層から見て放射性気体廃棄物の流れの上流側）で使用する場合は、２００℃以下で使用することが望ましい。２００℃より高温で使用すると、再結合触媒に流入する放射性気体廃棄物の温度が高くなり、再結合反応による発熱で再結合触媒が劣化する場合がある。不純物除去材は、再結合触媒上の再結合反応熱の輻射に注意する必要がある。輻射により不純物除去材の温度が上昇する場合は、捕捉した不純物を脱離する恐れがある。 When using activated carbon or mesoporous silica as an impurity removing material on the upper part of the recombination catalyst layer in the recombiner (upstream of the flow of radioactive gas waste as viewed from the recombination catalyst layer), the temperature is 200 ° C. or lower. It is desirable to use it. When used at a temperature higher than 200 ° C., the temperature of the radioactive gas waste flowing into the recombination catalyst becomes high, and the recombination catalyst may deteriorate due to heat generated by the recombination reaction. The impurity removing material needs to pay attention to radiation of recombination reaction heat on the recombination catalyst. When the temperature of the impurity removing material increases due to radiation, the trapped impurities may be desorbed.
　また、不純物除去材を再結合器の外に設置する場合には、不純物除去材の耐熱温度以下で使用することができる。ただし、放射性気体廃棄物全体を加熱するため、５００℃以下で使用することが望ましい。２００℃以上で使用する場合は、再結合器に放射性廃棄物を流入させる前に熱交換器などの冷却器を、不純物除去層と再結合触媒層の間に設置することが望ましい。 Also, when the impurity removing material is installed outside the recombiner, it can be used below the heat resistance temperature of the impurity removing material. However, in order to heat the whole radioactive gaseous waste, it is desirable to use it at 500 degrees C or less. When using at 200 degreeC or more, it is desirable to install coolers, such as a heat exchanger, between an impurity removal layer and a recombination catalyst layer, before making a radioactive waste flow into a recombiner.
　また、不純物除去材として、ＺｒＯ２またはＴｉＯ２を含む材料を使用する場合は、１８０℃以上で使用するとシロキサンを分解することができる。水蒸気が存在すれば、加水分解することができる。例えば、シロキサンの一種であるＣ１０Ｈ３０Ｏ５Ｓｉ５（Ｄ５）の分解反応は次式のようになる。 Further, when a material containing ZrO 2 or TiO 2 is used as the impurity removing material, siloxane can be decomposed when used at 180 ° C. or higher. If water vapor is present, it can be hydrolyzed. For example, the decomposition reaction of C 10 H 30 O 5 Si 5 (D5), which is a kind of siloxane, is represented by the following formula.
　　Ｃ１０Ｈ３０Ｏ５Ｓｉ５ + ５Ｈ２Ｏ → ５ＳｉＯ２ + １０ＣＨ４
　高温での使用は、不純物除去材表面に存在するＳｉＯ２が重合して被膜を形成しやすくなり、７００～７５０℃では被膜を形成してしまうため、７００℃未満で使用することが望ましい。再結合器内の再結合触媒層の上部で使用する場合は、２００℃より高温で使用すると、再結合触媒に流入する放射性気体廃棄物の温度が高くなり、再結合反応による発熱で再結合触媒が劣化する場合がある。 C 10 H 30 O 5 Si 5 + 5H 2 O → 5SiO 2 + 10CH 4
When used at high temperature, SiO 2 present on the surface of the impurity removing material is easily polymerized to form a film, and a film is formed at 700 to 750 ° C. Therefore, it is desirable to use at less than 700 ° C. When used above the recombination catalyst layer in the recombiner, when used at a temperature higher than 200 ° C., the temperature of the radioactive gas waste flowing into the recombination catalyst becomes high, and the recombination catalyst is generated due to the heat generated by the recombination reaction. May deteriorate.
　再結合触媒は６００℃以下で使用することが望ましく、５００℃以下で使用することがさらに好ましい。６００℃以上で使用すると、触媒活性成分のシンタリングが促進しやすくなり、性能が低下する。再結合触媒に流入するＨ２の量により、再結合反応による発熱は異なる。処理するＨ２の量を考慮し、再結合触媒の使用温度が６００℃以下となるよう不純物除去材の温度を設定することができる。不純物除去材を、再結合器の外に設置する場合には、２００℃以上で使用することができる。その場合は、再結合器に放射性廃棄物を流入させる前に、熱交換器などの冷却器を、不純物除去層と再結合触媒層の間に設置することが望ましい。 The recombination catalyst is desirably used at 600 ° C or lower, and more preferably at 500 ° C or lower. When used at 600 ° C. or higher, the sintering of the catalytically active component is easily promoted, and the performance is deteriorated. The exotherm due to the recombination reaction varies depending on the amount of H 2 flowing into the recombination catalyst. Considering the amount of H 2 to be treated, the temperature of the impurity removing material can be set so that the use temperature of the recombination catalyst is 600 ° C. or less. When the impurity removing material is installed outside the recombiner, it can be used at 200 ° C. or higher. In that case, it is desirable to install a cooler such as a heat exchanger between the impurity removal layer and the recombination catalyst layer before the radioactive waste flows into the recombiner.
　ＺｒＯ２と同様に使用温度を上げると捕捉後に分解特性を示す材料としては、化学的性質として酸点を有することが必要である。また、酸点は、単位表面積あたりに多く存在していることが望ましい。 As with ZrO 2 , a material that exhibits decomposition characteristics after trapping when the operating temperature is raised needs to have an acid point as a chemical property. Moreover, it is desirable that many acid sites exist per unit surface area.
　材料中の酸量を測定する一般的な方法として、ＮＨ３吸着法がある。ＮＨ３吸着法から求められた酸点量と、ＢＥＴ法により測定した材料の比表面積から、単位表面積あたりの酸点量を算出すると、前述のＺｒＯ２は０．００６４μｍｏｌ／ｍ２であり、これより多い値を持つ材料が望ましい。また、ＴｉＯ２は、０．００５１μｍｏｌ／ｍ２とＺｒＯ２よりは少ないが、同様の効果を示すと考えられる。また、ＺＳＭ－５は０．００１７ｍｏｌ／ｍ２だが、この程度までは、使用温度によるが同様の効果が得られると考えられる。０．００１７ｍｏｌ／ｍ２以上となるのは、他には活性アルミナなどがある。これらに第二成分を添加して酸点量を向上させて使用してもよい。なお、上記の酸点量は次のように測定した。 As a general method for measuring the amount of acid in the material, there is an NH 3 adsorption method. When the acid point amount per unit surface area is calculated from the acid point amount obtained from the NH 3 adsorption method and the specific surface area of the material measured by the BET method, the aforementioned ZrO 2 is 0.0064 μmol / m 2 , Materials with higher values are desirable. Further, TiO 2 is less than 0.0051μmol / m 2 and ZrO 2, is believed to show similar effects. ZSM-5 is 0.0017 mol / m 2, but up to this level, it is considered that the same effect can be obtained depending on the operating temperature. Other than that of 0.0017 mol / m 2 or more is activated alumina. A second component may be added to these to improve the acid point amount. In addition, said acid point amount was measured as follows.
　不純物除去材の酸点量は、金属露出度分析装置（日本ベル株式会社製ＢＥＬＣＡＴ－Ａ）を用いて測定した。不純物除去材は、０．５～１．０ｍｍ径の粒子を乳鉢で粉末にして用いた。試料量は０．０５ｇである。測定は、前処理工程、ＮＨ３吸着工程、及び昇温脱離工程からなる。 The acid point amount of the impurity removing material was measured using a metal exposure analyzer (BELCAT-A manufactured by Nippon Bell Co., Ltd.). As the impurity removing material, particles having a diameter of 0.5 to 1.0 mm were used in the form of powder in a mortar. The sample amount is 0.05 g. The measurement includes a pretreatment process, an NH 3 adsorption process, and a temperature programmed desorption process.
　前処理工程では、処理ガスとしてＨｅを５０ｍｌ／ｍｉｎで流通させ、室温から５００℃まで１０℃／ｍｉｎで昇温し、５００℃で６０ｍｉｎ保持した。その後、自然冷却により１００度まで温度を下げた。 In the pretreatment step, He was circulated as a treatment gas at 50 ml / min, the temperature was raised from room temperature to 500 ° C. at 10 ° C./min, and held at 500 ° C. for 60 min. Thereafter, the temperature was lowered to 100 degrees by natural cooling.
　ＮＨ３吸着工程では、ＮＨ３濃度が５ｖｏｌ％のＨｅ５０ｍｌ／ｍｉｎを、１００℃で３０ｍｉｎ流通させた。ＮＨ３を吸着させた後、ガスをＨｅに切り替え、５０ｍｌ／ｍｉｎで１５ｍｉｎ流通させた。 In the NH 3 adsorption step, He 50 ml / min with an NH 3 concentration of 5 vol% was circulated at 100 ° C. for 30 min. After adsorbing NH 3 , the gas was switched to He and allowed to flow for 15 min at 50 ml / min.
　昇温脱離工程では、Ｈｅを３０ｍｌ／ｍｉｎで流通させ、１００℃から７００℃へ１０℃／ｍｉｎで昇温した。７００℃到達後、２時間保持した。なお昇温時に脱離するＮＨ３は、ガスクロマトグラフ分析計で測定した。ガスクロマトグラフ分析計は、キャリアガスとしてＨｅを３０ｍｌ／ｍｉｎで流通させた。充填材カラムを使用せず、測定ガスはそのままＴＣＤ検出器に導入した。検出器温度は１００℃とした。 In the temperature programmed desorption process, He was circulated at 30 ml / min, and the temperature was increased from 100 ° C. to 700 ° C. at 10 ° C./min. After reaching 700 ° C., it was kept for 2 hours. NH 3 desorbed when the temperature was raised was measured with a gas chromatograph analyzer. The gas chromatograph analyzer circulated He as a carrier gas at 30 ml / min. The measurement gas was directly introduced into the TCD detector without using a packing material column. The detector temperature was 100 ° C.
　不純物除去材は、原子力プラントの再結合触媒のシロキサンによる被毒抑制、電気リレー部へのシロキサン付着による絶縁不良抑制、光学製品のシロキサン付着によるもや抑制、及び塗装表面へのシロキサン付着による塗料弾き抑制に使用することができる。また、シロキサンは、ドライクリーニング洗浄用薬品、シャンプー、化粧品、シリコンチューブやシリコングリースに含まれており、これらを使用する環境でもシロキサン含有物が発生する可能性があるため、前述のような事象抑制に不純物除去材を用いることができる。 Impurity-removing materials are used to reduce poisoning caused by siloxane as a recombination catalyst in nuclear power plants, suppress insulation failure due to adhesion of siloxane to electrical relays, suppress haze caused by adhesion of siloxane to optical products, and repel paint due to adhesion of siloxane to the coating surface Can be used for suppression. Siloxane is also contained in dry cleaning chemicals, shampoos, cosmetics, silicone tubes and silicone grease, and siloxane-containing substances may be generated even in the environment where these are used. An impurity removing material can be used.
　図７にシステムの処理フロー図を示す。シロキサンを含む流体またはシロキサン発生源１００を通過する流体を、シロキサンにより被毒させたくない装置１０２に流入させる前に、不純物除去材を含む不純物除去層１０１を通過させてから、シロキサンにより被毒させたくない装置１０２へ流入させ、排出させる。 Fig. 7 shows the processing flow diagram of the system. Before the fluid containing siloxane or the fluid passing through the siloxane generation source 100 is allowed to flow into the device 102 that is not desired to be poisoned by siloxane, the fluid is passed through the impurity removal layer 101 containing the impurity removing material and then poisoned by siloxane. It flows into the apparatus 102 which does not want to be discharged.
　放射性気体廃棄物に含まれる不純物としては、ケイ素化合物があり、一例としてシロキサンがある。シロキサンは、－ＯＳｉ（ＣＨ３）２－という基準構造が連続して結合し、最終的に環状となっている化合物である。基準構造の数により化合物の大きさが決まり、例えば、Ｄ５と記載する場合は、前述の基準構造が５つの環状化合物である。通常はＤ３～Ｄ８程度の化合物が対象となるが、本発明では、基準構造が２つ以下の化合物も不純物として対応可能である。基準構造が２つ以下の化合物では、環状構造を作れないため、直鎖状の構造となり、末端は－ＯＨとなっていると推定される。 As an impurity contained in the radioactive gas waste, there is a silicon compound, and an example is siloxane. Siloxane is a compound in which a reference structure of —OSi (CH 3 ) 2 — is continuously bonded and finally becomes a ring. The size of the compound is determined by the number of reference structures. For example, in the case of describing D5, the above-described reference structure is five cyclic compounds. Usually, compounds of about D3 to D8 are targeted, but in the present invention, compounds having two or less reference structures can also be handled as impurities. It is presumed that a compound having two or less reference structures cannot form a cyclic structure, and thus has a linear structure and has a terminal —OH.
　ケイ素化合物以外の不純物としては、炭化水素、硫酸化合物、塩素化合物、フッ素化合物がある。以下に述べる実施例では、代表例としてケイ素化合物にて試験を行ったが、本発明は、他の不純物についても同様の効果がある。 Impurities other than silicon compounds include hydrocarbons, sulfuric acid compounds, chlorine compounds, and fluorine compounds. In the examples described below, the test was conducted with a silicon compound as a representative example, but the present invention has the same effect with respect to other impurities.
　不純物除去材は、比表面積が大きいほうが望ましい。不純物除去材は、ミクロ孔、メソ孔を有する構造であると比表面積が大きくなり、捕捉する不純物量が増加する。また、ＺｒＯ２などの不純物除去材を、アルミナ、ＴｉＯ２、ゼオライト、メソポーラスシリカなどの高比表面積を持つ材料の上に担持させてもよい。これらの成分と複合化させ、複合酸化物化させて高比表面積化してもよい。 The impurity removing material preferably has a large specific surface area. When the impurity removing material has a structure having micropores and mesopores, the specific surface area becomes large, and the amount of impurities to be captured increases. Further, an impurity removing material such as ZrO 2 may be supported on a material having a high specific surface area such as alumina, TiO 2 , zeolite, or mesoporous silica. It may be combined with these components and converted into a composite oxide to increase the specific surface area.
　また、不純物除去材は、表面の疎水性や親水性を制御すると、シロキサン捕捉性能が向上する。例えば、ＺｒＯ２やメソポーラスシリカの表面性質を制御するために、Ｎｉ、Ｚｎ、Ｗ、Ｆｅ、Ｃｏ、Ｃｅ、Ｔｉなどの親水性成分を担持させてもよい。また、Ｆ、メチル基などの有機基などの疎水性成分を担持させてもよい。シロキサンは親水性のＳｉ基と疎水性の有機基を有するため、親水性を上げるとＳｉ基の捕捉性能が向上し、疎水性を向上させると有機基の捕捉性能が向上する。疎水性成分と塩基成分の両方を担持させてもよい。 Further, when the surface of the impurity removing material is controlled to be hydrophobic or hydrophilic, the siloxane trapping performance is improved. For example, in order to control the surface properties of ZrO 2 and mesoporous silica, hydrophilic components such as Ni, Zn, W, Fe, Co, Ce, and Ti may be supported. Moreover, you may carry | support hydrophobic components, such as organic groups, such as F and a methyl group. Since siloxane has a hydrophilic Si group and a hydrophobic organic group, increasing the hydrophilicity improves the Si group capturing performance, and improving the hydrophobicity improves the organic group capturing performance. You may carry | support both a hydrophobic component and a base component.
　図５に、原子炉からの排ガス処理フローを示す。原子炉で発生した放射性気体廃棄物に含まれる水蒸気（Ｈ２とＯ２を含む）は、タービンを回すために使用される。タービンを回した後の放射性気体廃棄物（排ガス）は、排ガス予熱器で所定温度まで加熱され、再結合器に導入される。再結合器では、Ｈ２とＯ２が結合してＨ２Ｏ（水蒸気）に変化する。再結合器を通過した後の排ガスは、復水器で水蒸気が水に戻され、さらに除湿冷却器で水分が除去される。 FIG. 5 shows an exhaust gas treatment flow from the nuclear reactor. Water vapor (including H 2 and O 2 ) contained in the radioactive gas waste generated in the nuclear reactor is used to turn the turbine. The radioactive gas waste (exhaust gas) after turning the turbine is heated to a predetermined temperature by the exhaust gas preheater and introduced into the recombiner. In the recombiner, H 2 and O 2 are combined and changed to H 2 O (water vapor). After the exhaust gas has passed through the recombiner, the steam is returned to the water by the condenser, and the moisture is removed by the dehumidifying cooler.
　以下、実施例にて本発明を説明するが、本発明は、これらの実施例に限定されるものではない。 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.
　本実施例では、不純物除去材として、ＺｒＯ２（材料１）、メソポーラスシリカ（材料２）、及び活性炭（材料３）を調製した。さらに、比較例として用いる不純物除去材として、ＴｉＯ２（比較１）とＺＳＭ－５（比較２）を調製した。 In this example, ZrO 2 (material 1), mesoporous silica (material 2), and activated carbon (material 3) were prepared as impurity removing materials. Further, TiO 2 (Comparative 1) and ZSM-5 (Comparative 2) were prepared as impurity removing materials used as comparative examples.
　＜材料１＞ＺｒＯ２
硝酸ジルコニル二水和物（市販品、和光純薬工業株式会社製試薬）を大気中で、５００℃で２時間焼成し、ＺｒＯ２を調製した。焼成後の粉末は、５００ｋｇｆ／ｃｍ２でプレス成型し、乳鉢で破砕し、０．５～１．０ｍｍに整粒した。 <Material 1> ZrO 2
Zirconyl nitrate dihydrate (commercial product, Wako Pure Chemical Industries, Ltd. reagent) was calcined in the atmosphere at 500 ° C. for 2 hours to prepare ZrO 2 . The fired powder was press-molded at 500 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
　＜材料２＞メソポーラスシリカ
メソポーラスシリカ（市販品、ズードケミー触媒株式会社製）を１２０℃で２時間乾燥させた。乾燥後の粉末は、２００ｋｇｆ／ｃｍ２でプレス成型し、乳鉢で破砕し、０．５～１．０ｍｍに整粒した。 <Material 2> Mesoporous silica Mesoporous silica (commercial product, manufactured by Zude Chemie Catalyst Co., Ltd.) was dried at 120 ° C. for 2 hours. The dried powder was press-molded at 200 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
　＜材料３＞活性炭
活性炭（市販品、武田薬品工業株式会社製、球状白鷺ＤＸ７－３（０．５～３．０ｍｍ径））を１２０℃で２時間乾燥させた。乾燥後、乳鉢で破砕し、０．５～１．０ｍｍに整粒した。 <Material 3> Activated carbon activated carbon (commercially available product, spherical white DX7-3 (0.5-3.0 mm diameter) manufactured by Takeda Pharmaceutical Co., Ltd.) was dried at 120 ° C. for 2 hours. After drying, the mixture was crushed with a mortar and sized to 0.5 to 1.0 mm.
　＜比較１＞ＴｉＯ２
粒径２～４ｍｍのＴｉＯ２（市販品、堺化学工業株式会社製ＣＳ－２００Ｓ－２４）を、乳鉢で破砕し、０．５～１．０ｍｍに整粒した。 <Comparison 1> TiO 2
TiO 2 having a particle diameter of 2 to 4 mm (commercial product, CS-200S-24 manufactured by Sakai Chemical Industry Co., Ltd.) was crushed with a mortar and sized to 0.5 to 1.0 mm.
　＜比較２＞ＺＳＭ－５
ＺＳＭ－５（市販品、ズードケミー触媒株式会社製Ｈ－ＭＦＩ－２４０）を、５００ｋｇｆ／ｃｍ２でプレス成型し、乳鉢で破砕し、０．５～１．０ｍｍに整粒した。 <Comparison 2> ZSM-5
ZSM-5 (commercial product, H-MFI-240 manufactured by Zude Chemie Catalysts Co., Ltd.) was press-molded at 500 kgf / cm 2 , crushed in a mortar, and sized to 0.5 to 1.0 mm.
　本実施例では、反応ガスに不純物としてシロキサンを添加し、実施例１で調製した不純物除去材の効果を調べた。具体的には、シロキサンを添加した反応ガスを、不純物除去層及び再結合触媒層を有する反応管に導入し、反応管の出口でのＨ２濃度を測定した。反応管の不純物除去層には不純物除去材が、再結合触媒層には再結合触媒が、それぞれ充填されている。 In this example, siloxane was added as an impurity to the reaction gas, and the effect of the impurity removing material prepared in Example 1 was examined. Specifically, the reaction gas to which siloxane was added was introduced into a reaction tube having an impurity removal layer and a recombination catalyst layer, and the H 2 concentration at the outlet of the reaction tube was measured. The impurity removal layer of the reaction tube is filled with an impurity removal material, and the recombination catalyst layer is filled with a recombination catalyst.
　反応ガスには、水２．４ｍｌ／ｍｉｎを水蒸気発生装置にて水蒸気に気化させ、Ｈ２９７ｍｌ／ｍｉｎとＯ２４８．３ｍｌ／ｍｉｎとを混合し、空気を１７．７ｍｌ／ｍｉｎ添加したものを用いた。この反応ガスを、再結合触媒層に１５０℃で流入させた。触媒量と反応ガス量との関係は、（式１）で示される空間速度が１０９，４００ｈ－１、（式２）で示される線速度が０．２９７ｍ／ｓとした。
空間速度（ｈ－１）＝反応ガス量（ｍｌ／ｈ－１）／触媒量（ｍｌ）（式１）
線速度（ｍ／ｓ）＝反応ガス流量（ｍ３／ｓ）／触媒断面積（ｍ２）（式２）
　反応管には、長さ方向の中央に再結合触媒としてＰｔ／Ａｌ２Ｏ３担持金属触媒を充填して再結合触媒層とした。さらに、金属触媒の上部（反応ガスの流れの上流側）に金網を敷き、金網の上に不純物除去材を充填して不純物除去層とした。金網を敷くのは、不純物除去材が下部（反応ガスの流れの下流側）に落ちないようにするためである。反応管に導入された反応ガスは、まず不純物除去層、次に再結合触媒層を通過し、出口に到達する。 As the reaction gas, water 2.4 ml / min is vaporized into water vapor by a steam generator, H 2 97 ml / min and O 2 48.3 ml / min are mixed, and air is added 17.7 ml / min. Was used. This reaction gas was allowed to flow at 150 ° C. into the recombination catalyst layer. Regarding the relationship between the catalyst amount and the reaction gas amount, the space velocity represented by (Equation 1) was 109,400 h −1 , and the linear velocity represented by (Equation 2) was 0.297 m / s.
Space velocity (h −1 ) = reaction gas amount (ml / h −1 ) / catalyst amount (ml) (formula 1)
Linear velocity (m / s) = reaction gas flow rate (m 3 / s) / catalyst cross-sectional area (m 2 ) (formula 2)
The reaction tube was filled with a Pt / Al 2 O 3 supported metal catalyst as a recombination catalyst at the center in the length direction to form a recombination catalyst layer. Further, a metal mesh was laid on the upper part of the metal catalyst (upstream side of the flow of the reaction gas), and an impurity removal material was filled on the metal mesh to form an impurity removal layer. The reason why the metal mesh is laid is to prevent the impurity removing material from falling to the lower part (downstream of the flow of the reaction gas). The reaction gas introduced into the reaction tube first passes through the impurity removal layer, then the recombination catalyst layer, and reaches the outlet.
　再結合触媒層を通過した反応ガス中のＨ２濃度は、氷冷した冷却槽で水蒸気を水に凝縮させた後のガスをＰＤＤ（Ｐｕｌｓｅｄ　Ｄｉｓｃｈａｒｇｅ　Ｄｅｔｅｃｔｏｒ）ガスクロマトグラフ分析計（ＧＬサイエンス株式会社製ＧＣ－４０００）に導入して測定した。ＰＤＤ検出器のモードは、ＨＩＤ（Ｈｅｌｉｕｍ　Ｉｏｎｉｚａｔｉｏｎ　Ｄｅｔｅｃｔｏｒ）を使用した。サンプルガス（再結合触媒層を通過した反応ガス）は、ポンプにて１００μｌを吸引した。ガスクロマトグラフのガス導入口温度は室温、検出器温度は１５０℃、オーブン温度は５０℃とした。カラムは、外径１／８インチφ×長さ２ｍであり、充填材としてＭｏｌｅｃｕｌａｒ　Ｓｉｅｖｅ　１３Ｘ－Ｓ（６０～８０メッシュ）を使用した。キャリアガスは、Ｈｅを２０ｍｌ／ｍｉｎで流した。また、放電ガスとしてＨｅを３０ｍｌ／ｍｉｎで流した。 The H 2 concentration in the reaction gas that has passed through the recombination catalyst layer is determined by using a PDD (Pulsed Discharge Detector) gas chromatograph analyzer (GC Science Co., Ltd. GC) after condensing water vapor into water in an ice-cooled cooling bath. -4000) and measured. As the mode of the PDD detector, HID (Helium Ionization Detector) was used. 100 μl of sample gas (reactive gas that passed through the recombination catalyst layer) was sucked with a pump. The gas inlet temperature of the gas chromatograph was room temperature, the detector temperature was 150 ° C., and the oven temperature was 50 ° C. The column had an outer diameter of 1/8 inch φ × length of 2 m, and Molecular Sieve 13X-S (60-80 mesh) was used as a packing material. As the carrier gas, He was allowed to flow at 20 ml / min. Further, He was allowed to flow at 30 ml / min as a discharge gas.
　不純物は、反応ガスを１５０℃に加熱し、不純物除去材及び再結合触媒を充填した反応管に導入し、反応管の出口のＨ２濃度（出口Ｈ２濃度）が安定した時点で、シロキサンの一種であるＤ５を反応管上部から２．５×１０－８リットル／ｍｉｎで滴下した。なお、試験毎に安定となる出口Ｈ２濃度が若干異なるため、Ｄ５を添加する直前の出口Ｈ２濃度を基準とし、Ｄ５添加後に上昇した出口Ｈ２濃度を比較した。 The impurities are heated to 150 ° C. and introduced into a reaction tube filled with an impurity removing material and a recombination catalyst, and when the H 2 concentration at the outlet of the reaction tube (outlet H 2 concentration) becomes stable, One type of D5 was added dropwise from the top of the reaction tube at 2.5 × 10 −8 liter / min. Incidentally, the outlet concentration of H 2 to be stable for each test differs slightly with respect to the outlet concentration of H 2 immediately before the addition of D5, was compared outlet concentration of H 2 was increased after addition of D5.
　図１は、反応ガスにＤ５を添加して３５分後と６０分後の出口Ｈ２濃度を比較した図である。反応管に不純物除去材を充填しない場合（再結合触媒のみを充填した場合）と、不純物除去材としてＺｒＯ２（材料１）、メソポーラスシリカ（ＭＰＳ、材料２）、活性炭（材料３）、ＴｉＯ２（比較１）、及びＺＳＭ－５（比較２）を充填した場合について、それぞれ比較した。ＺｒＯ２は、再結合触媒層の上部（反応ガスの流れの上流側）の不純物除去層に、１．８ｍｌ（２．５１ｇ）を充填した。同様に、メソポーラスシリカ（ＭＰＳ）は２．７ｍｌ（１．１１ｇ）を、活性炭は２．７ｍｌ（１．６３ｇ）を、ＴｉＯ２は１．８ｍｌ（１．７５ｇ）を、ＺＳＭ－５は２．７ｍｌ（２．０１ｇ）を、それぞれ充填した。また、比較のため、反応ガスにＤ５を添加せず、反応管に再結合触媒のみを充填した場合についても、出口Ｈ２濃度を測定した。 FIG. 1 is a diagram comparing outlet H 2 concentrations 35 minutes and 60 minutes after adding D5 to the reaction gas. When the impurity removing material is not filled in the reaction tube (when only the recombination catalyst is filled), ZrO 2 (material 1), mesoporous silica (MPS, material 2), activated carbon (material 3), TiO 2 are used as the impurity removing material. (Comparative 1) and ZSM-5 (Comparative 2) were filled and compared. ZrO 2 was charged with 1.8 ml (2.51 g) in the impurity removal layer on the upper part of the recombination catalyst layer (upstream side of the reaction gas flow). Similarly, 2.7 ml (1.11 g) for mesoporous silica (MPS), 2.7 ml (1.63 g) for activated carbon, 1.8 ml (1.75 g) for TiO 2 , and 2.10 for ZSM-5. 7 ml (2.01 g) was charged respectively. For comparison, the outlet H 2 concentration was also measured when D5 was not added to the reaction gas and only the recombination catalyst was filled in the reaction tube.
　Ｄ５を添加しない場合は、試験の間、出口Ｈ２濃度は上昇しなかった（図１において、出口Ｈ２濃度は、３５分後も６０分後も０ｖｏｌ％である）。 When D5 was not added, the outlet H 2 concentration did not increase during the test (in FIG. 1, the outlet H 2 concentration was 0 vol% after 35 and 60 minutes).
　一方、Ｄ５を添加し再結合触媒のみを充填した場合（不純物除去材を充填しない場合）は、出口Ｈ２濃度が反応時間とともに上昇した。図１には示していないが、出口Ｈ２濃度は、２時間後には３ｖｏｌ％を超えた。 On the other hand, when D5 was added and only the recombination catalyst was filled (when no impurity removing material was filled), the outlet H 2 concentration increased with the reaction time. Although not shown in FIG. 1, the outlet H 2 concentration exceeded 3 vol% after 2 hours.
　不純物除去材としてＺｒＯ２を充填した場合の出口Ｈ２濃度は、３５分後は再結合触媒のみを充填した場合とほぼ同じだが、６０分後は明らかに上昇が抑制された。また、メソポーラスシリカ（ＭＰＳ）を充填した場合と活性炭を充填した場合も、３５分後と６０分後の出口Ｈ２濃度の上昇が抑制された。 The outlet H 2 concentration when ZrO 2 was filled as an impurity removing material was almost the same as when only the recombination catalyst was filled after 35 minutes, but the increase was clearly suppressed after 60 minutes. In addition, when the mesoporous silica (MPS) was filled and when the activated carbon was filled, the increase in the outlet H 2 concentration after 35 minutes and after 60 minutes was suppressed.
　一方、不純物除去材としてＴｉＯ２を充填した場合とＺＳＭ－５を充填した場合は、出口Ｈ２濃度は、３５分後と６０分後のいずれも、不純物除去材を充填しない場合（再結合触媒のみを充填した場合）よりも高くなった。 On the other hand, when TiO 2 is filled as the impurity removing material and when ZSM-5 is filled, the concentration of the outlet H 2 is not filled with the impurity removing material after 35 minutes or 60 minutes (recombination catalyst). Higher when only filling).
　試験中の再結合触媒層の出口で測定した出口ガス温度は、最大で２８５℃であった。これは、再結合触媒上で再結合反応が進行し発熱したためである。 The outlet gas temperature measured at the outlet of the recombination catalyst layer under test was 285 ° C. at the maximum. This is because the recombination reaction proceeds on the recombination catalyst and heat is generated.
　ＺｒＯ２の場合、３５分後では不純物の除去効果はあまり見られていないが、これは、ＺｒＯ２表面にＤ５が付着し始まってから、反応ガス中からの除去効果が向上するためであると考えている。 In the case of ZrO 2 , the removal effect of impurities is not so much seen after 35 minutes, but this is because the removal effect from the reaction gas is improved after D5 starts to adhere to the ZrO 2 surface. thinking.
　また、ＺｒＯ２とＴｉＯ２の除去性能の違いは、比表面積と固体酸量の違いによると考えている。Ｄ５は除去材表面に吸着し、その吸着量は固体酸量に支配されると推定される。固体酸点は表面上で酸塩基反応が進行する点であり、単位比表面積あたりの固体酸量が吸着率を決定すると考えられる。ＺｒＯ２とＴｉＯ２の固体酸量を、ＮＨ３吸着法で調べた。 Moreover, it is thought that the difference in the removal performance of ZrO 2 and TiO 2 is due to the difference in specific surface area and the amount of solid acid. D5 is adsorbed on the surface of the removal material, and the amount of adsorption is estimated to be governed by the amount of solid acid. The solid acid point is a point where an acid-base reaction proceeds on the surface, and the solid acid amount per unit specific surface area is considered to determine the adsorption rate. The solid acid amounts of ZrO 2 and TiO 2 were examined by NH 3 adsorption method.
　ＮＨ３吸着法は、触媒にＮＨ３を吸着させ、その後、昇温しながら吸着ＮＨ３の脱離温度と脱離量を測定する方法である。脱離温度からＮＨ３の吸着力がわかる。 The NH 3 adsorption method is a method in which NH 3 is adsorbed on a catalyst, and then the desorption temperature and desorption amount of adsorbed NH 3 are measured while raising the temperature. The adsorption power of NH 3 can be seen from the desorption temperature.
　反応管に所定量の試料（ＺｒＯ２またはＴｉＯ２）を充填し、前処理を行った。前処理では、Ｈｅガス流通下で４５０℃まで昇温させ、４５０℃で３０分間保持することで、触媒表面に吸着している水分を除去した。ＮＨ３の吸着処理は、Ｈｅガスで９．５ｖｏｌ％に希釈したＮＨ３を反応管に導入して試料に吸着させた。吸着温度は１００℃とした。反応管出口からパルス的に流出する未吸着ガス濃度を定量し、この濃度が一定となった時点で吸着が完了したものと判断した。ＮＨ３は、吸着完了後、Ｈｅ気流中で７００℃まで昇温させて昇温脱離し、脱離するＮＨ３量を測定した。反応管出口のＮＨ３濃度は、ＴＣＤガスクロマトグラフで測定した。 A predetermined amount of sample (ZrO 2 or TiO 2 ) was filled in the reaction tube, and pretreatment was performed. In the pretreatment, the water adsorbed on the catalyst surface was removed by raising the temperature to 450 ° C. under a flow of He gas and maintaining the temperature at 450 ° C. for 30 minutes. Adsorption treatment of NH 3 was introduced and NH 3 was diluted to 9.5Vol% with He gas into the reaction tube is adsorbed on the sample. The adsorption temperature was 100 ° C. The concentration of unadsorbed gas flowing out in a pulse manner from the reaction tube outlet was quantified, and it was judged that the adsorption was completed when this concentration became constant. NH 3 was heated and desorbed by heating to 700 ° C. in a He stream after completion of adsorption, and the amount of NH 3 desorbed was measured. The NH 3 concentration at the outlet of the reaction tube was measured with a TCD gas chromatograph.
　ＢＥＴ法で測定した比表面積を用いると、ＺｒＯ２の固体酸量は０．０１５ｍｏｌ／ｍ２、ＴｉＯ２の固体酸量は０．０１２ｍｏｌ／ｍ２であった。このことから、不純物除去材には、少なくとも０．０１２ｍｏｌ／ｍ２以上の固体酸量が必要であることがわかった。固体酸量が多くなりすぎても、吸着した不純物同士の立体障害から除去性能は制限されると推定している。 Using the specific surface area measured by the BET method, the solid acid amount of ZrO 2 was 0.015 mol / m 2 , and the solid acid amount of TiO 2 was 0.012 mol / m 2 . From this, it was found that the impurity removing material requires a solid acid amount of at least 0.012 mol / m 2 or more. It is estimated that even if the amount of solid acid becomes too large, the removal performance is limited due to steric hindrance between adsorbed impurities.
　ＺＳＭ－５は、比表面積が大きく固体酸量も多いが、性能は低かった。これは、ＺＳＭ－５の耐水熱性の低さが影響していると考えられる。本実施例のような水蒸気が多い雰囲気で使用する場合には、表面の疎水化や、構造的に不安定なＳｉを含むＺＳＭ－５内部の不純物の十分な低減化が必要である。 ZSM-5 had a large specific surface area and a large amount of solid acid, but its performance was low. This is thought to be due to the low hydrothermal resistance of ZSM-5. When used in an atmosphere with a lot of water vapor as in this embodiment, it is necessary to make the surface hydrophobic and to sufficiently reduce impurities inside ZSM-5 containing structurally unstable Si.
　図２は、不純物除去層のＺｒＯ２の量を２．７ｍｌ（３．７７ｇ）に増やした場合の出口Ｈ２濃度の経時変化を示す図である。比較のため、反応ガスにＤ５を添加せず反応管に再結合触媒のみを充填した場合と、反応ガスにＤ５を添加して反応管に再結合触媒のみを充填した場合の結果も併せて示した。 FIG. 2 is a diagram showing a change with time of the outlet H 2 concentration when the amount of ZrO 2 in the impurity removal layer is increased to 2.7 ml (3.77 g). For comparison, the results when D5 is not added to the reaction gas and only the recombination catalyst is filled into the reaction tube and when only D5 is added to the reaction gas and the reaction tube is filled with only the recombination catalyst are also shown. It was.
　Ｄ５を添加しなかった場合は、出口Ｈ２濃度は上昇しなかった。一方、Ｄ５を添加して再結合触媒のみの場合では、反応時間とともに出口Ｈ２濃度が上昇した。Ｄ５を添加し、不純物除去材であるＺｒＯ２を不純物除去層に充填した場合では、出口Ｈ２濃度は上昇したが、再結合触媒のみの場合と比べて上昇が抑制された。 When D5 was not added, the outlet H 2 concentration did not increase. On the other hand, when D5 was added and only the recombination catalyst was used, the outlet H 2 concentration increased with the reaction time. When D5 was added and the impurity removal layer was filled with ZrO 2 as an impurity removal material, the concentration of the outlet H 2 was increased, but the increase was suppressed as compared with the case of using only the recombination catalyst.
　図１に示した場合と図２に示した場合とでは、図２の場合のほうが不純物除去層に充填したＺｒＯ２の量が多く、出口Ｈ２濃度の上昇が少ない。このことから、ＺｒＯ２の充填量を多くすると、出口Ｈ２濃度の上昇がさらに抑制されることがわかる。 In the case shown in FIG. 1 and the case shown in FIG. 2, the amount of ZrO 2 filled in the impurity removal layer is larger in the case of FIG. 2, and the increase in the outlet H 2 concentration is smaller. From this, it can be seen that increasing the filling amount of ZrO 2 further suppresses the increase in the outlet H 2 concentration.
　本実施例では、放射性気体廃棄物の処理設備における、不純物除去材の設置例を示す。 In this embodiment, an example of installing an impurity removing material in a radioactive gas waste treatment facility is shown.
　図３は、放射性気体廃棄物に含まれる水蒸気中の水素と酸素を触媒にて再結合させる再結合器の断面図の例である。再結合器３は、再結合触媒を充填した再結合触媒層２と、不純物除去材を充填した不純物除去層５とを備え、放射性気体廃棄物１が流入する。不純物除去層５は、再結合器３の内部で、再結合触媒層２から見て放射性気体廃棄物１の流れの上流側に設置される。さらに、再結合器３は加熱設備４を備える。加熱設備４には、例えばヒーターを用いる。 FIG. 3 is an example of a cross-sectional view of a recombiner that recombines hydrogen and oxygen in water vapor contained in radioactive gas waste with a catalyst. The recombiner 3 includes a recombination catalyst layer 2 filled with a recombination catalyst, and an impurity removal layer 5 filled with an impurity removal material, and the radioactive gas waste 1 flows in. The impurity removal layer 5 is installed in the recombiner 3 on the upstream side of the flow of the radioactive gas waste 1 when viewed from the recombination catalyst layer 2. Furthermore, the recombiner 3 includes a heating facility 4. For the heating equipment 4, for example, a heater is used.
　図３に示した例では、不純物除去層５は、カートリッジ６に充填されており、カートリッジ６は、カートリッジ支え７に保持されている。カートリッジ支え７は、再結合器３の内部に溶接されている。 In the example shown in FIG. 3, the impurity removal layer 5 is filled in the cartridge 6, and the cartridge 6 is held by the cartridge support 7. The cartridge support 7 is welded inside the recombiner 3.
　不純物除去層５は、再結合器３の中で温度が１００～２００℃となる部分に設置する。放射性気体廃棄物１の温度は、加熱設備４により、１００～２００℃となるように加熱制御される。加熱された放射性気体廃棄物１により、不純物除去層５の温度は、再結合触媒層２の温度が上昇しても、１００～２００℃の範囲内に保つことができる。 The impurity removal layer 5 is installed in the recombiner 3 where the temperature is 100 to 200 ° C. The temperature of the radioactive gas waste 1 is controlled to be 100 to 200 ° C. by the heating equipment 4. Due to the heated radioactive gas waste 1, the temperature of the impurity removal layer 5 can be kept within the range of 100 to 200 ° C. even if the temperature of the recombination catalyst layer 2 rises.
　温度が１００℃より低い部分に不純物除去材を設置すると、水蒸気が凝縮して所定の性能が得られない。また、２００℃を超えると、再結合触媒層２の温度制御が難しくなる。再結合触媒層２の入口温度が２００℃を超えると、再結合反応により触媒内部の温度が上昇し、触媒の劣化を引き起こす。 If the impurity removing material is installed in a part where the temperature is lower than 100 ° C., the water vapor is condensed and the predetermined performance cannot be obtained. Moreover, when it exceeds 200 degreeC, the temperature control of the recombination catalyst layer 2 will become difficult. When the inlet temperature of the recombination catalyst layer 2 exceeds 200 ° C., the temperature inside the catalyst rises due to the recombination reaction, causing deterioration of the catalyst.
　再結合触媒層２にて水素と酸素の再結合反応を効率良く行うためには、不純物除去層５を通過した放射性気体廃棄物１が１４０～１６０℃で再結合触媒層２に流入するのが望ましい。 In order to efficiently perform the recombination reaction between hydrogen and oxygen in the recombination catalyst layer 2, the radioactive gas waste 1 that has passed through the impurity removal layer 5 flows into the recombination catalyst layer 2 at 140 to 160 ° C. desirable.
　不純物除去材の形状としては、粒状、柱状、ペレット状などに成型して使用することができる。また、セラミックスハニカム表面にコートしてもよく、金属線表面にコートしてもよい。 The shape of the impurity removing material can be molded into a granular shape, a columnar shape, a pellet shape, or the like. Moreover, the ceramic honeycomb surface may be coated, or the metal wire surface may be coated.
　不純物除去層５は、多孔容器であるカートリッジ６に充填することが望ましい。多孔カートリッジ式とすることで、交換時には不純物除去層５のみを再結合器３から取り外すことができる。カートリッジ６は、カートリッジ支え７により保持されているが、再結合触媒層２の上部にカートリッジ支柱を置いて保持するようにしてもよい。 The impurity removal layer 5 is preferably filled in a cartridge 6 which is a porous container. By adopting a porous cartridge type, only the impurity removal layer 5 can be removed from the recombiner 3 at the time of replacement. Although the cartridge 6 is held by the cartridge support 7, a cartridge support may be placed on the recombination catalyst layer 2 and held.
　図４は、不純物除去材の別の設置例を示す図であり、再結合器と不純物除去層の断面図の例を示している。図４では、不純物除去材は、再結合器の外で、再結合器の前段に設置されている場合を示している。 FIG. 4 is a diagram showing another installation example of the impurity removing material, and shows an example of a cross-sectional view of the recombiner and the impurity removing layer. FIG. 4 shows a case where the impurity removing material is installed outside the recombiner and before the recombiner.
　再結合器３の前段には、通常、排ガス予熱器（図５参照）が配置されるが、排ガス予熱器と再結合器３との間に、不純物除去材を充填した不純物除去層５を設置してもよい。この場合は、再結合器３は、再結合触媒を充填した再結合触媒層２のみを備える。不純物除去層５は、カートリッジ６に充填されている。放射性気体廃棄物１は、不純物除去層５を通り、再結合器３に流入する。 An exhaust gas preheater (see FIG. 5) is usually arranged in the front stage of the recombiner 3, but an impurity removal layer 5 filled with an impurity removal material is installed between the exhaust gas preheater and the recombiner 3. May be. In this case, the recombiner 3 includes only the recombination catalyst layer 2 filled with the recombination catalyst. The impurity removal layer 5 is filled in the cartridge 6. The radioactive gas waste 1 passes through the impurity removal layer 5 and flows into the recombiner 3.
　不純物除去層５の周囲には、ヒーターなどの加熱設備４が備えられている。加熱設備４により放射性気体廃棄物１を１００～２００℃となるように加熱し、不純物除去層５の温度を１００～２００℃の範囲内に保つことができる。例えば、不純物除去層５の温度が低い場合には、加熱設備４で加熱し、所定の温度へ上げることができる。加熱方法としては、燃料を燃やした高温の排ガスを放射性気体廃棄物に混合してもよい。 A heating facility 4 such as a heater is provided around the impurity removal layer 5. The radioactive gaseous waste 1 can be heated to 100 to 200 ° C. by the heating equipment 4 and the temperature of the impurity removal layer 5 can be kept within the range of 100 to 200 ° C. For example, when the temperature of the impurity removal layer 5 is low, it can be heated by the heating equipment 4 and raised to a predetermined temperature. As a heating method, high temperature exhaust gas burned with fuel may be mixed with radioactive gas waste.
　また、図４に示したように、再結合器３の前段に不純物除去層５を設置する構造にすると、不純物除去層５を２つ以上配置することができる。図３に示した構造では、不純物除去層５は、再結合器３の内部に設置されており、設置する数に制限がある。不純物除去層５を２つ以上配置すると、緊急時や材料交換時にも、放射性気体廃棄物処理設備を運転したままで、作業をすることができるという利点がある。 Further, as shown in FIG. 4, when the structure in which the impurity removal layer 5 is installed in the previous stage of the recombiner 3, two or more impurity removal layers 5 can be arranged. In the structure shown in FIG. 3, the impurity removal layer 5 is installed inside the recombiner 3, and the number of installation is limited. When two or more impurity removal layers 5 are arranged, there is an advantage that the operation can be performed while operating the radioactive gas waste treatment facility even in an emergency or material exchange.
　本実施例では、実施例１の再結合触媒を取り除き、材料１（ＺｒＯ２）の前後のシロキサン類を分析し、不純物除去材の効果を調べた。具体的には、シロキサンを添加した反応ガスを、不純物除去層を有する反応管に導入し、反応管の出口でのシロキサン類の濃度を測定した。反応管の不純物除去層には、不純物除去材として材料１を充填した。また、不純物除去層を有しない反応管にも同一の反応ガスを流通させ、反応管の入口でのシロキサン類の濃度を測定した。 In this example, the recombination catalyst of Example 1 was removed, siloxanes before and after the material 1 (ZrO 2 ) were analyzed, and the effect of the impurity removing material was examined. Specifically, the reaction gas to which siloxane was added was introduced into a reaction tube having an impurity removal layer, and the concentration of siloxanes at the outlet of the reaction tube was measured. The impurity removal layer of the reaction tube was filled with material 1 as an impurity removal material. Further, the same reaction gas was passed through a reaction tube having no impurity removal layer, and the concentration of siloxanes at the inlet of the reaction tube was measured.
　反応ガスには、水０．８ｍｌ／ｍｉｎを水蒸気発生装置にて気化させ、空気を７．５ｍｌ／ｍｉｎ添加して水蒸気を供給した。４０ｍｌ／ｍｉｎのＨ２と２０．３ｍｌ／ｍｉｎのＯ２とを混合し、さらにヘリウムを２０２７．５ｍｌ／ｍｉｎ添加したものを用いた。ヘリウムの一部は、シロキサンの一種であるＤ５を供給するために用いた。 The reaction gas was vaporized with 0.8 ml / min of water using a steam generator, and added with 7.5 ml / min of air to supply water vapor. 40 ml / min of H 2 and 20.3 ml / min of O 2 were mixed and helium was further added at 2027.5 ml / min. Part of helium was used to supply D5, a kind of siloxane.
　この反応ガスを、不純物除去層に９２～２８９℃で流入させた。不純物除去材の量は、２．７ｍｌ（３．７６ｇ）とした。 The reaction gas was allowed to flow into the impurity removal layer at 92 to 289 ° C. The amount of the impurity removing material was 2.7 ml (3.76 g).
　反応管には、実施例１と同一の位置に材料１を充填した。材料１の高さ位置を合わせるため、再結合触媒層部分にはアルミナウールを充填した。反応管に導入された反応ガスは、不純物除去層を通過し、出口に到達する。 The reaction tube was filled with material 1 at the same position as in Example 1. In order to match the height position of the material 1, the recombination catalyst layer portion was filled with alumina wool. The reaction gas introduced into the reaction tube passes through the impurity removal layer and reaches the outlet.
　再結合触媒層を通過した反応ガス中のＨ２濃度は、実施例１と同様に測定した。シロキサン類の測定は、氷冷した冷却槽で水蒸気を水に凝縮させた後のガスを採取し、質量分析計にて測定した。 The H 2 concentration in the reaction gas that passed through the recombination catalyst layer was measured in the same manner as in Example 1. The siloxanes were measured by collecting gas after condensing water vapor into water in an ice-cooled cooling bath and measuring with a mass spectrometer.
　シロキサンの一種であるＤ５は、液体を一定温度で保温し、ヘリウムをバブリングして供給した。 D5, which is a kind of siloxane, kept the liquid at a constant temperature and was supplied by bubbling helium.
　図６は、反応ガスにＤ５を添加して３０分後の、材料１（不純物除去材）の温度とＤ５減少率を示した図である。Ｄ５減少率は、材料１の温度が９２℃（実施例１の反応ガス温度１５０℃に相当）では２５．０％と低いが、１８０℃では８６．８％、２２０℃では９１．８％、２５７℃では９６．４％となり、２８９℃では９９．６％となることがわかった。シロキサン類の分析と合わせて、メタン（ＣＨ４）の分析も行ったところ、Ｄ５減少量の約１０倍のＣＨ４が検出され、
Ｄ５の分解が示唆された。従って、材料１の効果は、吸着したシロキサンを分解することと考えている。 FIG. 6 is a graph showing the temperature of the material 1 (impurity removing material) and the D5 reduction rate 30 minutes after adding D5 to the reaction gas. The D5 reduction rate is as low as 25.0% when the temperature of the material 1 is 92 ° C. (corresponding to the reaction gas temperature of 150 ° C. in Example 1), but is 86.8% at 180 ° C., 91.8% at 220 ° C. It was found to be 96.4% at 257 ° C. and 99.6% at 289 ° C. When analysis of methane (CH 4 ) was also performed in combination with analysis of siloxanes, about 10 times as much CH 4 as D5 reduction was detected,
Degradation of D5 was suggested. Therefore, the effect of the material 1 is considered to decompose the adsorbed siloxane.
　本発明は、原子力発電所での放射性気体廃棄物の処理に利用できる。 The present invention can be used for the treatment of radioactive gas waste at nuclear power plants.
　１…放射性気体廃棄物、２…再結合触媒層、３…再結合器、４…加熱設備、５…不純物除去層、６…カートリッジ、７…カートリッジ支え、１００…シロキサン発生源、１０１…不純物除去層、１０２…被毒させたくない装置。 DESCRIPTION OF SYMBOLS 1 ... Radioactive waste, 2 ... Recombination catalyst layer, 3 ... Recombiner, 4 ... Heating equipment, 5 ... Impurity removal layer, 6 ... Cartridge, 7 ... Cartridge support, 100 ... Siloxane generation source, 101 ... Impurity removal Layer, 102 ... Device that you do not want to poison.

Claims (13)

  1. 　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを触媒にて再結合させる放射性気体廃棄物処理方法において、
    　前記放射性気体廃棄物に含まれる不純物を、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材と接触させて除去する工程と、
    　前記不純物を除去した後、前記放射性気体廃棄物を前記触媒と接触させて前記水素と前記酸素とを再結合させる工程と、
    を備えることを特徴とする放射性気体廃棄物処理方法。     In a radioactive gas waste treatment method in which hydrogen and oxygen in water vapor contained in radioactive gas waste discharged from a nuclear reactor power plant are recombined with a catalyst,
    Removing impurities contained in the radioactive gas waste by contacting with an impurity removing material containing at least one of ZrO 2 , mesoporous silica, and activated carbon;
    After removing the impurities, contacting the radioactive gaseous waste with the catalyst to recombine the hydrogen and oxygen;
    A radioactive gas waste treatment method comprising:
  2. 　前記不純物は、少なくともケイ素化合物を含む請求項１記載の放射性気体廃棄物処理方法。 2. The radioactive gas waste treatment method according to claim 1, wherein the impurities include at least a silicon compound.
  3. 　前記不純物除去材は、１００℃から５００℃の温度域で使用する請求項１記載の放射性気体廃棄物処理方法。 The radioactive gas waste treatment method according to claim 1, wherein the impurity removing material is used in a temperature range of 100 ° C to 500 ° C.
  4. 　前記不純物除去材は、少なくともミクロ孔またはメソ孔を有する請求項１記載の放射性気体廃棄物処理方法。 2. The radioactive gas waste processing method according to claim 1, wherein the impurity removing material has at least micropores or mesopores.
  5. 　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる不純物を除去する不純物除去材であって、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含むことを特徴とする不純物除去材。 An impurity removing material for removing impurities contained in radioactive gas waste discharged from a nuclear reactor at a nuclear power plant, wherein the impurity removing material includes at least one of ZrO 2 , mesoporous silica, and activated carbon. Wood.
  6. 　少なくともミクロ孔またはメソ孔を有する請求項５記載の不純物除去材。 6. The impurity removing material according to claim 5, which has at least micropores or mesopores.
  7. 　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを再結合させる再結合触媒層を有する再結合器を備える放射性気体廃棄物処理設備において、
    　前記再結合器の前段で前記放射性気体廃棄物を加熱する排ガス予熱器と、
    　前記排ガス予熱器と前記再結合器との間に、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材を充填した不純物除去層と、
    を備えることを特徴とする放射性気体廃棄物処理設備。     In a radioactive gas waste treatment facility comprising a recombiner having a recombination catalyst layer for recombining hydrogen and oxygen in water vapor contained in radioactive gas waste discharged from a nuclear reactor at a nuclear power plant,
    An exhaust gas preheater for heating the radioactive gas waste in a stage preceding the recombiner;
    An impurity removal layer filled with an impurity removal material containing at least one of ZrO 2 , mesoporous silica, and activated carbon between the exhaust gas preheater and the recombiner;
    A radioactive gas waste treatment facility comprising:
  8. 　原子力発電所で原子炉から排出される放射性気体廃棄物に含まれる水蒸気中の水素と酸素とを再結合させる再結合触媒層を有する再結合器を備える放射性気体廃棄物処理設備において、
    　前記再結合器は、ＺｒＯ２、メソポーラスシリカ、及び活性炭のうち少なくとも一つを含む不純物除去材を充填した不純物除去層を備え、
    　前記不純物除去層と前記再結合触媒層は、前記放射性気体廃棄物が前記再結合器の中をこの順で通過するように配置されたことを特徴とする放射性気体廃棄物処理設備。     In a radioactive gas waste treatment facility comprising a recombiner having a recombination catalyst layer for recombining hydrogen and oxygen in water vapor contained in radioactive gas waste discharged from a nuclear reactor at a nuclear power plant,
    The recombiner includes an impurity removal layer filled with an impurity removal material containing at least one of ZrO 2 , mesoporous silica, and activated carbon,
    The radioactive gas waste treatment facility, wherein the impurity removal layer and the recombination catalyst layer are arranged so that the radioactive gas waste passes through the recombiner in this order.
  9. 　前記不純物は、少なくともケイ素化合物を含む請求項７または８記載の放射性気体廃棄物処理設備。 The radioactive gas waste treatment facility according to claim 7 or 8, wherein the impurities include at least a silicon compound.
  10. 　前記不純物除去材は、少なくともミクロ孔またはメソ孔を有する請求項７または８記載の放射性気体廃棄物処理設備。 The radioactive gas waste treatment facility according to claim 7 or 8, wherein the impurity removing material has at least micropores or mesopores.
  11. 　前記放射性気体廃棄物を１００～２００℃に加熱する加熱設備を備え、
    　前記加熱設備で加熱された前記放射性気体廃棄物により、前記不純物除去層の温度を１００～２００℃にする請求項７または８記載の放射性気体廃棄物処理設備。     A heating facility for heating the radioactive gas waste to 100-200 ° C .;
    The radioactive gas waste treatment facility according to claim 7 or 8, wherein the temperature of the impurity removal layer is set to 100 to 200 ° C by the radioactive gas waste heated by the heating facility.
  12. 　シロキサンを分解除去する方法において、シロキサン含有ガスを、水蒸気の存在下で、ＺｒＯ２とＴｉＯ２のうち少なくとも１つを含む不純物除去材と接触させて分解することを特徴とするシロキサンの分解除去方法。 A method for decomposing and removing siloxane, comprising: decomposing and removing siloxane-containing gas by contacting with an impurity removing material containing at least one of ZrO 2 and TiO 2 in the presence of water vapor. .
  13. 　請求項１２記載のシロキサンの分解除去方法において、前記シロキサン含有ガスを前記不純物除去材と１８０℃以上で接触させるシロキサンの分解除去方法。 The method for decomposing and removing siloxane according to claim 12, wherein the siloxane-containing gas is brought into contact with the impurity removing material at 180 ° C or higher.
PCT/JP2011/051416 2010-01-27 2011-01-26 Treatment method, treatment facility and impurity-removing material for radioactive gaseous waste WO2011093305A1 (en)

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JP2011203035A (en) * 2010-03-25 2011-10-13 Hitachi-Ge Nuclear Energy Ltd Nuclear power plant with boiling water reactor
JP2013186052A (en) * 2012-03-09 2013-09-19 Ibiden Co Ltd Method for removing cesium from contaminated water including radioactive substance, and honeycomb structure for cesium removal
JP2013221890A (en) * 2012-04-18 2013-10-28 Toshiba Corp Vent device and vent method for reactor containment vessel
JP2014006221A (en) * 2012-06-27 2014-01-16 Hitachi-Ge Nuclear Energy Ltd Siloxane degrading material, and apparatus and method for treating gaseous waste using the same
JP2014083511A (en) * 2012-10-25 2014-05-12 Hitachi-Ge Nuclear Energy Ltd Siloxane decomposition apparatus

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JP2011203035A (en) * 2010-03-25 2011-10-13 Hitachi-Ge Nuclear Energy Ltd Nuclear power plant with boiling water reactor
JP2013186052A (en) * 2012-03-09 2013-09-19 Ibiden Co Ltd Method for removing cesium from contaminated water including radioactive substance, and honeycomb structure for cesium removal
JP2013221890A (en) * 2012-04-18 2013-10-28 Toshiba Corp Vent device and vent method for reactor containment vessel
JP2014006221A (en) * 2012-06-27 2014-01-16 Hitachi-Ge Nuclear Energy Ltd Siloxane degrading material, and apparatus and method for treating gaseous waste using the same
JP2014083511A (en) * 2012-10-25 2014-05-12 Hitachi-Ge Nuclear Energy Ltd Siloxane decomposition apparatus

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