WO2017203567A1 - Radionuclide separation method and radionuclide separation device - Google Patents

Radionuclide separation method and radionuclide separation device Download PDF

Info

Publication number
WO2017203567A1
WO2017203567A1 PCT/JP2016/065182 JP2016065182W WO2017203567A1 WO 2017203567 A1 WO2017203567 A1 WO 2017203567A1 JP 2016065182 W JP2016065182 W JP 2016065182W WO 2017203567 A1 WO2017203567 A1 WO 2017203567A1
Authority
WO
WIPO (PCT)
Prior art keywords
radionuclide
fluoride
temperature
separation
separated
Prior art date
Application number
PCT/JP2016/065182
Other languages
French (fr)
Japanese (ja)
Inventor
祐子 可児
笹平　朗
大輔 渡邉
Original Assignee
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社日立製作所 filed Critical 株式会社日立製作所
Priority to JP2018518818A priority Critical patent/JP6621917B2/en
Priority to PCT/JP2016/065182 priority patent/WO2017203567A1/en
Publication of WO2017203567A1 publication Critical patent/WO2017203567A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/12—Dry methods smelting of sulfides or formation of mattes by gases
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B25/00—Obtaining tin
    • C22B25/02—Obtaining tin by dry processes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/14—Obtaining zirconium or hafnium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • 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
    • G21F9/04—Treating liquids
    • G21F9/06—Processing
    • 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
    • G21F9/04—Treating liquids
    • G21F9/06—Processing
    • G21F9/08—Processing by evaporation; by distillation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a technique for separating a radionuclide, and more particularly to a method for separating a predetermined radionuclide from a high-level radioactive liquid waste and a separation apparatus for performing the method.
  • high-level radioactive liquid waste in which radionuclides contained in spent fuel are dissolved appear.
  • the high-level radioactive liquid waste is currently being considered for vitrification and disposal.
  • the waste liquid and the vitrified body are collectively referred to as high-level radioactive waste.
  • Radionuclides with a relatively long half-life may be eluted from the vitrified material by contact with groundwater while high-level radioactive waste is buried for a long period of time. There is a concern that it will become a source of public exposure when it reaches the surface.
  • the burden on the environment and human body due to the disposal of high-level radioactive waste is reduced by separating and recovering long-lived radionuclides from the high-level radioactive waste before being buried. It is being considered.
  • the separated long-lived radionuclide can be transmuted to another short-lived radionuclide or non-radionuclide by a nuclear reaction using a nuclear reactor or accelerator. Can be overcome.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2015-227780 discloses a method for separating a nuclide of a vitrified body, in which a vitrified body containing a radionuclide and a white metal element is dissolved. And a separation and recovery step of separating and recovering the radionuclide from the dissolved glass solidified body, wherein the melting step fluorinates the glass solidified body at a high temperature, and the fluoride of the glass solidified body is recovered.
  • a fluorination step for dissolving in a gas and the separation and recovery step includes a cooling step for cooling the fluoride and separating each of the radionuclides into gas-liquid or gas-solid according to a difference in boiling point.
  • a method for separating nuclides of a vitrified product is proposed.
  • a radionuclide can be efficiently separated and recovered from a vitrified material containing high-level radioactive waste. Further, in separating radionuclides, from the viewpoint of suppressing the volume of high-level radioactive waste, a dry process is considered preferable to a wet process that tends to increase in volume due to the addition of a solvent or the like.
  • Patent Document 1 since the separation method described in Patent Document 1 uses the difference in the boiling point of the radionuclide fluoride, it is necessary to heat to the boiling point of the radionuclide fluoride to be separated, and the heat treatment temperature is high. There is a difficulty of becoming.
  • Patent Document 1 for example, when separating strontium (Sr) or samarium (Sm), it is necessary to heat the strontium fluoride (boiling point 2460 ° C) or higher than the boiling point of samarium fluoride (boiling point 2323 ° C). There is a weak point that the apparatus cost and the operation cost for doing so tend to increase (that is, the recovery cost tends to increase).
  • fluorides with similar boiling points for example, cesium (Cs) fluoride with a boiling point of 1251 ° C and aluminum (Al) fluoride with a boiling point of 1260 ° C, zirconium (Zr) fluoride with a boiling point of about 900 ° C and a boiling point of about 800 ° C Of tin (Sn) fluoride
  • Cs cesium
  • Al aluminum
  • Zr zirconium
  • an object of the present invention is to separate a radionuclide more easily (that is, at a low cost) while securing a separation rate equal to or higher than that of the prior art, and to execute the method. It is in providing the separation apparatus for doing.
  • One aspect of the present invention is a method for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated, A radioactive liquid waste solidifying step of evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid; A radionuclide fluoride conversion step in which fluorine gas (F 2 ) is allowed to act on the high-level radioactive solid to convert the radionuclide to be separated contained in the high-level radioactive solid into a fluoride; The saturated vapor pressure of the radionuclide fluoride to be separated is heated to a temperature at which the vapor pressure is equal to or higher than the partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than the atmospheric pressure.
  • the present invention provides a radionuclide separation method characterized by comprising a radionuclide fluoride volatilization separation step for volatilizing and separating fluor
  • the present invention can add the following improvements and changes to the radionuclide separation method (I).
  • It further has a radionuclide fluoride solidifying step of cooling the volatile gas of the radionuclide fluoride to be separated to solidify the nuclide fluoride.
  • the radionuclide fluoride volatile separation step is a heat treatment in a temperature range of 500 ° C. or higher and 900 ° C. or lower performed while flowing a carrier gas.
  • the radionuclide fluoride volatile separation step is a heat treatment in which the temperature is gradually raised within the temperature range.
  • the radionuclide fluoride volatile separation step is a heat treatment in which the temperature on the upstream side of the carrier gas is increased within the temperature range and the temperature is gradually decreased toward the downstream side of the carrier gas.
  • the radionuclide fluoride volatile separation step is a heat treatment for gradually increasing the temperature on the downstream side of the carrier gas within the temperature range.
  • the radionuclide to be separated is one or more of tin (Sn), zirconium (Zr), and cesium (Cs).
  • the radionuclide fluoride conversion step is a heat treatment in a temperature range of less than 400 ° C.
  • the radioactive liquid waste solidifying step is a heat treatment in a temperature range of 400 ° C. or higher and 600 ° C. or lower.
  • Another aspect of the present invention is a separation apparatus for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated, A waste liquid storage tank containing the high-level radioactive liquid waste; A waste liquid solidifying device for evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid; A radionuclide fluorination apparatus that converts the radionuclide to be separated contained in the high-level radioactive solid into fluoride by allowing the high-level radioactive solid to act on fluorine gas; A fluoride volatilization separation device that heats the radionuclide fluoride to be separated while flowing a carrier gas to volatilize and separate the nuclide fluoride; The fluoride volatile separation device has a vapor pressure of a saturated vapor pressure of the radionuclide fluoride to be separated that is equal to or higher than a partial pressure calculated from the content of the nuclide fluor
  • the present invention can be modified or changed as follows in the radionuclide separation apparatus (II).
  • the apparatus further includes a fluoride solidifying device that cools the volatile gas of the radionuclide fluoride to be separated and solidifies the nuclide fluoride.
  • the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature within a temperature range of 500 ° C. or more and 900 ° C. or less.
  • the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature to gradually increase within the temperature range.
  • the fluoride volatile separation device has a mechanism capable of constructing a temperature profile in which the temperature on the upstream side of the carrier gas is increased and the temperature gradually decreases toward the downstream side of the carrier gas.
  • the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature on the downstream side of the carrier gas so as to gradually increase within the temperature range.
  • the radionuclide to be separated is one or more of tin, zirconium and cesium.
  • the radionuclide fluorination device has a fluorination temperature control mechanism that controls the temperature range to be less than 400 ° C.
  • the waste liquid solidification apparatus has a waste liquid solidification temperature control mechanism that controls the temperature range from 400 ° C. to 600 ° C.
  • a method capable of separating radionuclides more easily (that is, at low cost) while ensuring a separation rate equal to or higher than that of the prior art, and to execute the method can be provided.
  • the technique described in Patent Document 1 is a method for separating radionuclides from a vitrified substance in which a plurality of types of radionuclides are mixed, and all of the plurality of types of radionuclides are temporarily fluorinated and vaporized. After that, when cooling the fluoride gas, it is a technique of separating using the difference in boiling point of each fluoride.
  • the separation method of Patent Document 1 has a weak point that the equipment cost and operation cost of the separation apparatus are likely to increase because a high heat treatment temperature is required.
  • fluorides having close boiling points have a weak point that they are easy to mix (separation rate tends to decrease).
  • the present inventors diligently studied a method capable of separating radionuclides at a lower cost while ensuring a separation rate equal to or higher than that of the prior art.
  • the present inventors have focused on the vapor pressure of fluoride and found that a predetermined radionuclide can be separated at a high separation rate by utilizing the difference in vapor pressure depending on temperature.
  • Fluoride has a vapor pressure even below the boiling point, and its saturated vapor pressure increases rapidly as an exponential function as the temperature rises.
  • the temperature at which the saturated vapor pressure becomes equal to the external pressure (for example, atmospheric pressure) is the boiling point.
  • each fluoride gas has a partial pressure corresponding to the respective mole fraction in the mixture. Assuming that the total pressure (sum of partial pressures) is atmospheric pressure, each partial pressure is naturally less than atmospheric pressure.
  • each partial pressure is less than atmospheric pressure. Therefore, the temperature at which the predetermined fluoride reaches the vapor pressure at which it evaporates is less than the boiling point of the fluoride. In other words, the fluoride to be separated can be volatilized and separated without heating the fluoride mixture to the boiling point or higher of the fluoride to be separated.
  • FIG. 1 is a schematic diagram showing a configuration example of a radionuclide separation apparatus according to the present invention.
  • the radionuclide separation apparatus 100 of the present invention generates a high-level radioactive solid by evaporating a liquid phase component of a waste liquid storage tank 10 for storing a high-level radioactive waste liquid and a high-level radioactive waste liquid.
  • Waste liquid solidification device 20 radionuclide fluorination device 30 that causes high-level radioactive solids to react with fluorine gas to convert the radionuclides to be separated contained in the high-level radioactive solids into radionuclide fluorides, and the radioactivity to be separated
  • a fluoride volatilization separation device 40 that heats the nuclide fluoride to volatilize and separate the nuclide fluoride.
  • a fluoride solidifying device 50 for cooling the volatile gas of the radionuclide fluoride to be separated and solidifying the nuclide fluoride may be further provided downstream of the fluoride volatile separation device 40.
  • the high-level radioactive liquid waste contains, for example, cesium (Cs), strontium (Sr), zirconium (Zr), palladium (Pd), tin (Sn) as the cationic species, and, for example, nitrate ions (NO 3 ⁇ ) as the anionic species. It is an aqueous solution.
  • the liquid waste storage tank 10 is not particularly limited, and a conventional liquid waste storage tank can be used.
  • the type of radionuclide contained in the high-level radioactive liquid waste and the radionuclide to be separated in the liquid waste are determined.
  • Information on the content is required. Therefore, when the composition of the high-level radioactive liquid waste is unknown, it is preferable to perform a waste liquid composition investigation step that at least investigates the type and molar fraction of the cation with respect to the high-level radioactive liquid waste.
  • the waste liquid solidification device 20 is a device that performs a radioactive waste liquid solidification process that evaporates liquid phase components in the high level radioactive waste liquid to generate high level radioactive solids (for example, radionuclide oxide powder and nitrate powder in the waste liquid).
  • a waste liquid solidification heat treatment furnace 21 for example, a rotary kiln
  • a waste liquid solidification temperature control mechanism 22 for controlling the heat treatment temperature.
  • a waste liquid solidification atmosphere control mechanism 23 for example, an atmosphere containing oxygen (O 2 ) sufficient to generate an oxide of a radionuclide in the waste liquid, for example, air or oxygen
  • the heat treatment temperature in the radioactive waste liquid solidification step is preferably a temperature at which oxides or nitrates of radionuclides in the waste liquid are generated and a temperature at which the generated oxides or nitrates are not volatilized.
  • it is preferably 400 ° C. or higher and 600 ° C. or lower, and more preferably 450 ° C. or higher and 550 ° C. or lower.
  • the radionuclide fluorination device 30 is a device that performs a radionuclide fluoride conversion process in which fluorine gas is allowed to act on a high-level radioactive solid to convert the radionuclide to be separated contained in the high-level radioactive solid into a radionuclide fluoride.
  • a fluorination heat treatment furnace 31 for example, a fluidized bed apparatus
  • a fluorination temperature control mechanism 32 for controlling the heat treatment temperature
  • a fluorination atmosphere control mechanism 33 for controlling the heat treatment atmosphere to a fluorine atmosphere.
  • a gas supply mechanism or a vacuum exhaust mechanism for example, a gas supply mechanism or a vacuum exhaust mechanism.
  • the heat treatment temperature in the radionuclide fluoride conversion step is preferably a temperature at which the fluorination reaction proceeds and the fluoride of the radionuclide to be separated does not volatilize, for example, 200 ° C. or more and less than 400 ° C.
  • control is performed to increase the temperature in order to promote the fluorination reaction.
  • the fluorination heat treatment furnace 31 Control to cool down.
  • the high-level radioactive liquid waste contains an element (for example, selenium (Se) or tellurium (Te)) that generates a fluoride having a lower boiling point than the fluoride of the radionuclide to be separated, the element The fluoride is volatilized during this step and discharged from an off-gas pipe (not shown) of the fluorination heat treatment furnace 31 to be separated from the high-level radioactive solid.
  • an off-gas pipe not shown
  • the fluoride volatilization separation device 40 is a device for performing a radionuclide fluoride volatilization separation process for heating and separating the radionuclide fluoride to be separated to volatilize and separate the nuclide fluoride, and the temperature profile in the furnace can be controlled.
  • a fluoride volatilization heat treatment furnace 41 equipped with a mechanism, a fluoride volatilization temperature control mechanism 42 for controlling the heat treatment temperature, and a carrier gas control mechanism 43 (for example, a gas supply mechanism or a vacuum exhaust mechanism) for controlling the carrier gas .
  • the heat treatment temperature of the radionuclide fluoride volatile separation step is such that the saturated vapor pressure of the radionuclide fluoride to be separated is not less than the partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than atmospheric pressure.
  • the temperature at which the vapor pressure is reached is preferred. For example, it is preferably 500 ° C. or higher and 900 ° C. or lower.
  • the fluoride volatilization temperature control mechanism 42 performs control so that the entire temperature in the furnace becomes a substantially constant temperature. In addition, it is more preferable to perform control to gradually raise the temperature within a desired temperature range.
  • the carrier gas control mechanism 43 efficiently discharges the volatilized fluoride gas from the fluoride volatilization heat treatment furnace 41 (that is, separates the radionuclide fluoride to be separated from the high-level radioactive solid) into a fluoride volatilization heat treatment. This is a mechanism for flowing a carrier gas into the furnace 41.
  • the carrier gas an inert gas that does not chemically react with the radionuclide fluoride is preferable.
  • nitrogen (N 2 ) or argon (Ar) can be preferably used.
  • FIG. 2 is a graph showing the relationship between saturated vapor pressure and temperature of cesium fluoride, zirconium fluoride and tin fluoride.
  • Cesium and zirconium are long half-life radionuclides to be separated.
  • Tin is an element contained in the high-level radioactive liquid waste, and is an element that can be easily mixed with zirconium because of its close boiling point.
  • the saturation vapor pressure-temperature curves are greatly different even in the case of fluorides having close boiling points (zirconium fluoride, tin fluoride). Further, it is confirmed that the saturated vapor pressure increases rapidly as the temperature increases. For example, it can be seen that the saturation vapor pressures of zirconium fluoride and tin fluoride differ by about two orders of magnitude at 600 ° C., and differ by about one order of magnitude even at 800 ° C. In the present invention, element separation is efficiently performed by utilizing such a large saturated vapor pressure difference.
  • FIG. 3A is an example of a set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step.
  • FIG. 3B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 3A.
  • the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is a constant temperature of 800 ° C. throughout the furnace.
  • the radionuclide fluoride that has not volatilized in the radionuclide fluoride volatilization separation process resides in the fluoride volatilization heat treatment furnace 41 and can be collected separately.
  • the fluoride solidification device 50 is a device that performs a radionuclide fluoride solidification step of solidifying the radionuclide fluoride by cooling the volatile gas of the radionuclide fluoride to be separated, and is equipped with a mechanism that can be heated or cooled It has a solidification heat treatment furnace 51 and a fluoride solidification temperature control mechanism 52 for controlling the heat treatment temperature.
  • the heat treatment temperature of the radionuclide fluoride solidification step is not particularly limited as long as the fluoride gas discharged from the fluoride volatilization heat treatment furnace 41 in the previous step (radionuclide fluoride volatilization separation step) is solidified surely.
  • 200 ° C. is preferable.
  • the fluoride solidification heat treatment furnace 51 has a solid fluoride recovery container 51 ', and it is preferable that the solid fluoride recovery container 51' has a structure that can be easily replaced.
  • the solid fluoride recovery container 51 ′ has a structure that can be easily replaced, the solid fluoride recovery container 51 ′ is replaced for each fluoride. This makes it easy to collect radionuclides.
  • the furnace temperature profile of the fluoride volatilization heat treatment furnace 41 is set to a constant temperature throughout the furnace as shown in FIG. 3A, and gradually within the above temperature range (500 to 900 ° C.). Heat treatment for raising the temperature to a higher value is more preferable.
  • tin fluoride can be volatilized from about 500 ° C., but volatilization of zirconium fluoride and cesium fluoride requires temperatures of about 650 ° C. and 700 ° C., respectively. . Therefore, by gradually increasing the heat treatment temperature from 500 ° C., a sufficient time difference can be created for the start of rising of the separation rate of each fluoride in FIG. 3B.
  • the tin fluoride since only the tin fluoride is volatilized when the heat treatment temperature is 500 to 650 ° C., the tin component can be selectively separated. Thereafter, when the heat treatment temperature is 650 to 700 ° C., substantially only zirconium fluoride is volatilized, so that the zirconium component can be selectively separated. Thereafter, when the heat treatment temperature is further increased, only the cesium fluoride is substantially volatilized, so that the cesium component can be selectively separated. As a result, the probability of mixing each component decreases, so that the separation accuracy can be improved.
  • the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step is different from that of the first embodiment, and the others are the same. It is. Therefore, only the in-furnace temperature profile of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step will be described.
  • FIG. 4A is another example of the set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step.
  • FIG. 4B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 4A.
  • the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is 900 ° C. at the carrier gas upstream side (furnace inlet side) at the start of heat treatment.
  • the temperature on the downstream side of the carrier gas (furnace outlet side) is set to 400 ° C so that the temperature decreases almost linearly from the upstream side to the downstream side of the carrier gas.
  • the temperature on the side (furnace outlet side) is gradually increased, and finally the temperature on the downstream side of the carrier gas is controlled to be 900 ° C.
  • tin fluoride begins to be discharged out of the furnace at a carrier gas downstream temperature of about 500 ° C., and almost the entire amount is discharged out of the furnace at a carrier gas downstream temperature of about 600 ° C.
  • zirconium fluoride and cesium fluoride are hardly discharged outside the furnace, and the tin component can be almost completely separated from the fluoride mixture.
  • zirconium fluoride and cesium fluoride begin to be discharged out of the furnace, but their separation rate rises (gradient of change in separation rate) are greatly different. I understand.
  • the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step is different from those of the first and second embodiments. It is the same thing. Therefore, only the in-furnace temperature profile of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step will be described.
  • FIG. 5A is another example of the set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step.
  • FIG. 5B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 5A.
  • the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is set to 900 ° C. at the carrier gas upstream end (furnace inlet side) at the start of heat treatment.
  • the temperature on the downstream side of the carrier gas (furnace outlet side) is fixed at 700 ° C., and is set so that the temperature decreases almost linearly from the upstream side to the downstream side of the carrier gas.
  • both the zirconium fluoride and the cesium fluoride start to be discharged out of the furnace, but the rise of the separation rate (gradient of change in the separation rate) is greatly different between the two.
  • the cesium fluoride at this time has a “separation rate ⁇ 0.2”. This means that about 17% of cesium fluoride is mixed in the zirconium fluoride collected outside the furnace, but zirconium fluoride is not mixed in the cesium fluoride remaining in the furnace.
  • the separation accuracy of the zirconium component and the cesium component can be improved by repeating this step.
  • Radionuclide separation device 10 ... Waste liquid storage tank, 20 ... Waste liquid solidification device, 21 ... Waste liquid solidification heat treatment furnace, 22 ... Waste liquid solidification temperature control mechanism, 23 ... Waste liquid solidification atmosphere control mechanism, 30 ... Radionuclide fluorination device, 31 ... Fluorine heat treatment furnace, 32 ... Fluoride temperature control mechanism, 33 ... Fluoride atmosphere control mechanism, 40 ... Fluoride volatilization separation device, 41 ... Fluoride volatilization heat treatment furnace, 42 ... Fluoride volatilization temperature control mechanism, 43 ... Carrier Gas control mechanism, 50 ... fluoride solidification device, 51 ... fluoride solidification heat treatment furnace, 51 '... solid fluoride recovery container, 52 ... fluoride solidification temperature control mechanism.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

The purpose of the present invention is to provide a method for the separation of radionuclides, said method allowing for radionuclides to be separated more easily while maintaining a separation rate comparable to or higher than that of conventional methods, and a separation device for executing said method. The radionuclide separation method according to the present invention is a method for separating radionuclides to be separated from highly radioactive wastewater containing radionuclides to be separated, the method including: a radioactive wastewater solidification step for vaporizing the liquid-phase component of the highly radioactive wastewater so as to produce a highly radioactive solid; a radionuclide fluoride conversion step in which fluorine gas acts upon the highly radioactive solid so as to convert the target radionuclides in the highly radioactive solid into a fluoride; and a radionuclide fluoride volatilization/separation step in which the radionuclide fluoride is volatilized and separated by being heated to a temperature such that the saturation vapor pressure of the radionuclide fluoride being separated is equal to or greater than a partial pressure calculated from the radionuclide fluoride content of the highly radioactive solid but is less than atmospheric pressure.

Description

放射性核種の分離方法および放射性核種の分離装置Radionuclide separation method and radionuclide separation apparatus
　本発明は、放射性核種を分離する技術に関し、特に高レベル放射性廃液から所定の放射性核種を分離する方法および該方法を実行するための分離装置に関するものである。 The present invention relates to a technique for separating a radionuclide, and more particularly to a method for separating a predetermined radionuclide from a high-level radioactive liquid waste and a separation apparatus for performing the method.
　原子力発電で使用した燃料を再処理する過程において、再利用されるウラン（U）およびプルトニウム（Pu）を回収した後には、使用済燃料に含まれていた放射性核種が溶解した高レベル放射性廃液が発生する。当該高レベル放射性廃液は、現在、ガラス固化して埋設処分することが検討されている。以下、該廃液および該ガラス固化体を総称して高レベル放射性廃棄物という。 In the process of reprocessing fuel used in nuclear power generation, after recovering uranium (U) and plutonium (Pu) to be reused, high-level radioactive liquid waste in which radionuclides contained in spent fuel are dissolved appear. The high-level radioactive liquid waste is currently being considered for vitrification and disposal. Hereinafter, the waste liquid and the vitrified body are collectively referred to as high-level radioactive waste.
　高レベル放射性廃棄物には、数多くの放射性核種が含まれている。このうち、比較的半減期の長い放射性核種（長半減期放射性核種）は、高レベル放射性廃棄物が長期間にわたって埋設されている間に地下水等と接触することでガラス固化体から溶出する可能性があり、それが地表に到達すると公衆の被曝源となることが懸念される。 High level radioactive waste contains many radionuclides. Among them, radionuclides with a relatively long half-life (long-half-life radionuclides) may be eluted from the vitrified material by contact with groundwater while high-level radioactive waste is buried for a long period of time. There is a concern that it will become a source of public exposure when it reaches the surface.
　そのような懸念に対処するため、埋設処分する前の高レベル放射性廃棄物から長半減期放射性核種を分離回収することで、高レベル放射性廃棄物の埋設処分による環境や人体への負荷を低減することが検討されている。なお、分離回収した長半減期放射性核種は、原子炉や加速器を使った核反応により別の短半減期放射性核種や非放射性核種に核変換することができ、それにより長半減期放射性核種の難点を克服することができる。 In order to address such concerns, the burden on the environment and human body due to the disposal of high-level radioactive waste is reduced by separating and recovering long-lived radionuclides from the high-level radioactive waste before being buried. It is being considered. The separated long-lived radionuclide can be transmuted to another short-lived radionuclide or non-radionuclide by a nuclear reaction using a nuclear reactor or accelerator. Can be overcome.
　放射性核種の分離方法として、例えば、特許文献１（特開2015-227780）には、ガラス固化体の核種分離方法であって、放射性核種と白金属元素とを含むガラス固化体を溶解させる溶解工程と、溶解させた前記ガラス固化体から前記放射性核種を分離して回収する分離回収工程とを含み、前記溶解工程は、高温下で前記ガラス固化体をフッ素化し、前記ガラス固化体のフッ化物を気体中に溶解させるフッ素化工程を有し、前記分離回収工程は、前記フッ化物を冷却して、沸点の差異により前記放射性核種のそれぞれを気液または気固分離する冷却工程を有することを特徴とするガラス固化体の核種分離方法が提案されている。 As a method for separating radionuclides, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-227780) discloses a method for separating a nuclide of a vitrified body, in which a vitrified body containing a radionuclide and a white metal element is dissolved. And a separation and recovery step of separating and recovering the radionuclide from the dissolved glass solidified body, wherein the melting step fluorinates the glass solidified body at a high temperature, and the fluoride of the glass solidified body is recovered. A fluorination step for dissolving in a gas, and the separation and recovery step includes a cooling step for cooling the fluoride and separating each of the radionuclides into gas-liquid or gas-solid according to a difference in boiling point. A method for separating nuclides of a vitrified product is proposed.
特開２０１５－２２７７８０号公報JP2015-227780A
　特許文献１によると、高レベル放射性廃棄物を含有するガラス固化体から放射性核種を効率的に分離回収することができるとされている。また、放射性核種を分離するにあたって、高レベル放射性廃棄物の容積を抑制する観点からは、溶媒等の添加により容積が増加し易いウエットプロセスよりも、ドライプロセスの方が好ましいと考えられる。 According to Patent Document 1, it is said that a radionuclide can be efficiently separated and recovered from a vitrified material containing high-level radioactive waste. Further, in separating radionuclides, from the viewpoint of suppressing the volume of high-level radioactive waste, a dry process is considered preferable to a wet process that tends to increase in volume due to the addition of a solvent or the like.
　しかしながら、特許文献１に記載の分離方法は、放射性核種フッ化物の沸点の差異を利用するものであることから、分離対象の放射性核種フッ化物の沸点以上に加熱する必要があり、熱処理温度が高温化するという難点がある。 However, since the separation method described in Patent Document 1 uses the difference in the boiling point of the radionuclide fluoride, it is necessary to heat to the boiling point of the radionuclide fluoride to be separated, and the heat treatment temperature is high. There is a difficulty of becoming.
　特許文献１によると、例えば、ストロンチウム（Sr）やサマリウム（Sm）を分離する場合、ストロンチウムフッ化物（沸点2460℃）やサマリウムフッ化物（沸点2323℃）の沸点以上に加熱する必要があり、分離するための装置コストや運転コストが増大し易い（すなわち、回収コストが増加し易い）という弱点がある。 According to Patent Document 1, for example, when separating strontium (Sr) or samarium (Sm), it is necessary to heat the strontium fluoride (boiling point 2460 ° C) or higher than the boiling point of samarium fluoride (boiling point 2323 ° C). There is a weak point that the apparatus cost and the operation cost for doing so tend to increase (that is, the recovery cost tends to increase).
　また、沸点が近いフッ化物同士（例えば、沸点1251℃のセシウム（Cs）フッ化物と沸点1260℃のアルミニウム（Al）フッ化物や、沸点約900℃のジルコニウム（Zr）フッ化物と沸点約800℃のスズ（Sn）フッ化物）は混合する可能性があり、分離率が不十分になることが懸念される。 Also, fluorides with similar boiling points (for example, cesium (Cs) fluoride with a boiling point of 1251 ° C and aluminum (Al) fluoride with a boiling point of 1260 ° C, zirconium (Zr) fluoride with a boiling point of about 900 ° C and a boiling point of about 800 ° C Of tin (Sn) fluoride) may be mixed, and there is a concern that the separation rate becomes insufficient.
　一方、処理・処分すべき高レベル放射性廃棄物の総量は年々増加しており、有効かつ安全な処理・処分方法が強く求められている。言い換えると、高い分離率が得られかつ簡便に（すなわち低コストで）放射性核種の分離が可能な方法に対するニーズは強い。 On the other hand, the total amount of high-level radioactive waste to be treated and disposed of is increasing year by year, and there is a strong demand for effective and safe disposal and disposal methods. In other words, there is a strong need for a method capable of obtaining a high separation rate and easily separating radionuclides (ie, at low cost).
　したがって、本発明の目的は、放射性核種の分離において、従来技術と同等以上の分離率を確保しながら、より簡便に（すなわち低コストで）放射性核種の分離が可能な方法、および該方法を実行するための分離装置を提供することにある。 Accordingly, an object of the present invention is to separate a radionuclide more easily (that is, at a low cost) while securing a separation rate equal to or higher than that of the prior art, and to execute the method. It is in providing the separation apparatus for doing.
　（I）本発明の一態様は、分離対象の放射性核種を含む高レベル放射性廃液から該分離対象の放射性核種を分離する方法であって、
前記高レベル放射性廃液の液相成分を蒸発させて高レベル放射性固体を生成する放射性廃液固化工程と、
前記高レベル放射性固体にフッ素ガス（F2）を作用させて該高レベル放射性固体に含まれる前記分離対象の放射性核種をフッ化物に転換する放射性核種フッ化物転換工程と、
前記分離対象の放射性核種フッ化物の飽和蒸気圧が、前記高レベル放射性固体中の該核種フッ化物の含有率から算出される分圧以上大気圧未満の蒸気圧となる温度に加熱して該核種フッ化物を揮発させて分離する放射性核種フッ化物揮発分離工程とを有することを特徴とする放射性核種の分離方法を提供するものである。 (I) One aspect of the present invention is a method for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated,
A radioactive liquid waste solidifying step of evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid;
A radionuclide fluoride conversion step in which fluorine gas (F 2 ) is allowed to act on the high-level radioactive solid to convert the radionuclide to be separated contained in the high-level radioactive solid into a fluoride;
The saturated vapor pressure of the radionuclide fluoride to be separated is heated to a temperature at which the vapor pressure is equal to or higher than the partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than the atmospheric pressure. The present invention provides a radionuclide separation method characterized by comprising a radionuclide fluoride volatilization separation step for volatilizing and separating fluoride.
　本発明は、上記の放射性核種の分離方法（I）において、以下のような改良や変更を加えることができる。
（i）前記分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化する放射性核種フッ化物固化工程を更に有する。
（ii）前記放射性核種フッ化物揮発分離工程は、キャリアガスを流しながら行う500℃以上900℃以下の温度範囲の熱処理である。
（iii）前記放射性核種フッ化物揮発分離工程は、前記温度範囲内で徐々に昇温する熱処理である。
（iv）前記放射性核種フッ化物揮発分離工程は、前記温度範囲内で前記キャリアガスの上流側の温度を高く、該キャリアガスの下流に向かって徐々に温度を低くする熱処理である。
（v）前記放射性核種フッ化物揮発分離工程は、前記キャリアガスの下流側の温度を前記温度範囲内で徐々に昇温する熱処理である。
（vi）前記分離対象の放射性核種は、スズ（Sn）、ジルコニウム（Zr）およびセシウム（Cs）の内の一つ以上である。
（vii）前記放射性核種フッ化物転換工程は、400℃未満の温度範囲の熱処理である。
（viii）前記放射性廃液固化工程は、400℃以上600℃以下の温度範囲の熱処理である。 The present invention can add the following improvements and changes to the radionuclide separation method (I).
(I) It further has a radionuclide fluoride solidifying step of cooling the volatile gas of the radionuclide fluoride to be separated to solidify the nuclide fluoride.
(Ii) The radionuclide fluoride volatile separation step is a heat treatment in a temperature range of 500 ° C. or higher and 900 ° C. or lower performed while flowing a carrier gas.
(Iii) The radionuclide fluoride volatile separation step is a heat treatment in which the temperature is gradually raised within the temperature range.
(Iv) The radionuclide fluoride volatile separation step is a heat treatment in which the temperature on the upstream side of the carrier gas is increased within the temperature range and the temperature is gradually decreased toward the downstream side of the carrier gas.
(V) The radionuclide fluoride volatile separation step is a heat treatment for gradually increasing the temperature on the downstream side of the carrier gas within the temperature range.
(Vi) The radionuclide to be separated is one or more of tin (Sn), zirconium (Zr), and cesium (Cs).
(Vii) The radionuclide fluoride conversion step is a heat treatment in a temperature range of less than 400 ° C.
(Viii) The radioactive liquid waste solidifying step is a heat treatment in a temperature range of 400 ° C. or higher and 600 ° C. or lower.
　（II）本発明の他の一態様は、分離対象の放射性核種を含む高レベル放射性廃液から該分離対象の放射性核種を分離する分離装置であって、
前記高レベル放射性廃液を収容する廃液貯槽と、
前記高レベル放射性廃液の液相成分を蒸発させて高レベル放射性固体を生成する廃液固化装置と、
前記高レベル放射性固体をフッ素ガスと作用させて該高レベル放射性固体に含まれる前記分離対象の放射性核種をフッ化物に転換する放射性核種フッ化装置と、
キャリアガスを流しながら前記分離対象の放射性核種フッ化物を加熱して該核種フッ化物を揮発させて分離するフッ化物揮発分離装置とを有し、
前記フッ化物揮発分離装置は、前記分離対象の放射性核種フッ化物の飽和蒸気圧が、前記高レベル放射性固体中の該核種フッ化物の含有率から算出される分圧以上大気圧未満の蒸気圧となる所定の温度範囲に制御するフッ化物揮発温度制御機構を有することを特徴とする放射性核種の分離装置を提供するものである。 (II) Another aspect of the present invention is a separation apparatus for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated,
A waste liquid storage tank containing the high-level radioactive liquid waste;
A waste liquid solidifying device for evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid;
A radionuclide fluorination apparatus that converts the radionuclide to be separated contained in the high-level radioactive solid into fluoride by allowing the high-level radioactive solid to act on fluorine gas;
A fluoride volatilization separation device that heats the radionuclide fluoride to be separated while flowing a carrier gas to volatilize and separate the nuclide fluoride;
The fluoride volatile separation device has a vapor pressure of a saturated vapor pressure of the radionuclide fluoride to be separated that is equal to or higher than a partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than atmospheric pressure. The present invention provides a radionuclide separation device having a fluoride volatilization temperature control mechanism for controlling to a predetermined temperature range.
　本発明は、上記の放射性核種の分離装置（II）において、以下のような改良や変更を加えることができる。
（ix）前記分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化するフッ化物固化装置を更に有する。
（x）前記フッ化物揮発温度制御機構は、500℃以上900℃以下の温度範囲に制御する機構である。
（xi）前記フッ化物揮発温度制御機構は、前記温度範囲で徐々に昇温するように制御する機構である。
（xii）前記フッ化物揮発分離装置は、前記キャリアガスの上流側の温度を高く、該キャリアガスの下流に向かって徐々に温度が低くなる温度プロファイルを構築できる機構を有する。
（xiii）前記フッ化物揮発温度制御機構は、前記キャリアガスの下流側の温度を前記温度範囲内で徐々に昇温するように制御する機構である。
（xiv）前記分離対象の放射性核種は、スズ、ジルコニウムおよびセシウムの内の一つ以上である。
（xv）前記放射性核種フッ化装置は、400℃未満の温度範囲に制御するフッ化温度制御機構を有する。
（xvi）前記廃液固化装置は、400℃以上600℃以下の温度範囲に制御する廃液固化温度制御機構を有する。 The present invention can be modified or changed as follows in the radionuclide separation apparatus (II).
(Ix) The apparatus further includes a fluoride solidifying device that cools the volatile gas of the radionuclide fluoride to be separated and solidifies the nuclide fluoride.
(X) The fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature within a temperature range of 500 ° C. or more and 900 ° C. or less.
(Xi) The fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature to gradually increase within the temperature range.
(Xii) The fluoride volatile separation device has a mechanism capable of constructing a temperature profile in which the temperature on the upstream side of the carrier gas is increased and the temperature gradually decreases toward the downstream side of the carrier gas.
(Xiii) The fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature on the downstream side of the carrier gas so as to gradually increase within the temperature range.
(Xiv) The radionuclide to be separated is one or more of tin, zirconium and cesium.
(Xv) The radionuclide fluorination device has a fluorination temperature control mechanism that controls the temperature range to be less than 400 ° C.
(Xvi) The waste liquid solidification apparatus has a waste liquid solidification temperature control mechanism that controls the temperature range from 400 ° C. to 600 ° C.
　本発明によれば、放射性核種の分離において、従来技術と同等以上の分離率を確保しながら、より簡便に（すなわち低コストで）放射性核種の分離が可能な方法、および該方法を実行するための分離装置を提供することができる。 According to the present invention, in the separation of radionuclides, a method capable of separating radionuclides more easily (that is, at low cost) while ensuring a separation rate equal to or higher than that of the prior art, and to execute the method Can be provided.
本発明に係る放射性核種の分離装置の構成例を示す模式図である。It is a schematic diagram which shows the structural example of the separation apparatus of the radionuclide which concerns on this invention. セシウムフッ化物、ジルコニウムフッ化物およびスズフッ化物の飽和蒸気圧と温度との関係を示すグラフである。It is a graph which shows the relationship between the saturated vapor pressure and temperature of a cesium fluoride, a zirconium fluoride, and a tin fluoride. 放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの一例である。It is an example of the preset temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. 図３Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。It is a graph which shows an example of the relationship between the heat processing time in the heat processing conditions of FIG. 3A, and the separation rate of a fluoride. 放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの他の一例である。It is another example of the preset temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. 図４Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。It is a graph which shows an example of the relationship between the heat processing time in the heat processing conditions of FIG. 4A, and the separation rate of a fluoride. 放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの他の一例である。It is another example of the preset temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. 図５Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。It is a graph which shows an example of the relationship between the heat processing time in the heat processing conditions of FIG. 5A, and the separation rate of a fluoride.
　［本発明の基本思想］
　前述したように、特許文献１に記載の技術は、複数種の放射性核種が混在するガラス固化体から放射性核種を分離する方法であって、複数種全ての放射性核種を一旦フッ化物化して気化させた後、該フッ化物ガスを冷却する際に各フッ化物の沸点の差異を利用して分離する技術である。ただし、特許文献１の分離方法は、高い熱処理温度が必要なことから分離装置の設備コストや運転コストが増大し易いという弱点があった。また、沸点が近いフッ化物同士は混合し易い（分離率が低下し易い）という弱点があった。 [Basic idea of the present invention]
As described above, the technique described in Patent Document 1 is a method for separating radionuclides from a vitrified substance in which a plurality of types of radionuclides are mixed, and all of the plurality of types of radionuclides are temporarily fluorinated and vaporized. After that, when cooling the fluoride gas, it is a technique of separating using the difference in boiling point of each fluoride. However, the separation method of Patent Document 1 has a weak point that the equipment cost and operation cost of the separation apparatus are likely to increase because a high heat treatment temperature is required. In addition, fluorides having close boiling points have a weak point that they are easy to mix (separation rate tends to decrease).
　このような弱点に対し、本発明者等は、従来技術と同等以上の分離率を確保しながら、より低コストで放射性核種の分離が可能な方法について鋭意検討した。その中で、本発明者等は、フッ化物の蒸気圧に着目し、温度による蒸気圧の差異を利用することによって所定の放射性核種を高い分離率で分離できることを見出した。 In response to such weak points, the present inventors diligently studied a method capable of separating radionuclides at a lower cost while ensuring a separation rate equal to or higher than that of the prior art. Among them, the present inventors have focused on the vapor pressure of fluoride and found that a predetermined radionuclide can be separated at a high separation rate by utilizing the difference in vapor pressure depending on temperature.
　分離の原理について簡単に説明する。フッ化物は沸点以下でも蒸気圧を有し、その飽和蒸気圧は温度が上昇すると指数関数のように急激に大きくなる。飽和蒸気圧と外圧（例えば大気圧）とが等しくなる温度が沸点である。 簡 単 Briefly explain the principle of separation. Fluoride has a vapor pressure even below the boiling point, and its saturated vapor pressure increases rapidly as an exponential function as the temperature rises. The temperature at which the saturated vapor pressure becomes equal to the external pressure (for example, atmospheric pressure) is the boiling point.
　分離処理する対象物として、複数種のフッ化物の混合物を想定する。複数種全てのフッ化物が気相になったとすると、各フッ化物ガスは、混合物中のそれぞれのモル分率に応じた分圧を有することになる。全圧（分圧の合計）を大気圧とすると、各分圧は当然のことながら大気圧未満である。 Suppose a mixture of multiple types of fluoride as an object to be separated. If all of the plurality of types of fluorides are in the gas phase, each fluoride gas has a partial pressure corresponding to the respective mole fraction in the mixture. Assuming that the total pressure (sum of partial pressures) is atmospheric pressure, each partial pressure is naturally less than atmospheric pressure.
　ある温度におけるあるフッ化物の飽和蒸気圧が該フッ化物の分圧未満の場合、該フッ化物の揮発は起こらない。言い換えると、あるフッ化物の飽和蒸気圧が混合物中のモル分率に応じた分圧以上になると、該フッ化物のみが揮発し始めることになる。 When the saturated vapor pressure of a certain fluoride at a certain temperature is lower than the partial pressure of the fluoride, the volatilization of the fluoride does not occur. In other words, when the saturated vapor pressure of a certain fluoride is equal to or higher than the partial pressure corresponding to the molar fraction in the mixture, only the fluoride begins to volatilize.
　全圧が大気圧の場合、各分圧は大気圧未満であることから、所定のフッ化物が揮発する蒸気圧に達する温度は該フッ化物の沸点未満の温度である。すなわち、フッ化物の混合物を分離対象のフッ化物の沸点以上まで加熱しなくても、該分離対象のフッ化物を揮発分離することができる。 When the total pressure is atmospheric pressure, each partial pressure is less than atmospheric pressure. Therefore, the temperature at which the predetermined fluoride reaches the vapor pressure at which it evaporates is less than the boiling point of the fluoride. In other words, the fluoride to be separated can be volatilized and separated without heating the fluoride mixture to the boiling point or higher of the fluoride to be separated.
　フッ化物の沸点未満の温度で分離可能になることから、従来技術に比して、分離装置の設備コストや運転コストを抑制することができる。また、飽和蒸気圧は温度の上昇と共に急激に大きくなることから、小さな温度差（例えば10℃）であっても大きな蒸気圧差となる。このことから、沸点が近いフッ化物同士であっても高い分離率を達成できる。本発明は、これらの知見に基づいて完成されたものである。 Since separation becomes possible at a temperature lower than the boiling point of fluoride, the equipment cost and operation cost of the separation device can be suppressed as compared with the prior art. Further, since the saturated vapor pressure increases rapidly as the temperature rises, even if the temperature difference is small (for example, 10 ° C.), the vapor pressure difference becomes large. Therefore, a high separation rate can be achieved even with fluorides having close boiling points. The present invention has been completed based on these findings.
　以下、本発明の実施形態について、図面を参照しながら詳細に説明する。なお、本発明はここで取り上げた実施形態に限定されることはなく、発明の技術的思想を逸脱しない範囲で適宜組み合わせや改良が可能である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the embodiments taken up here, and can be appropriately combined and improved without departing from the technical idea of the invention.
　［本発明の第１実施形態］
　（放射性核種の分離装置および分離方法）
　図１は、本発明に係る放射性核種の分離装置の構成例を示す模式図である。図１に示したように、本発明の放射性核種の分離装置100は、高レベル放射性廃液を収容する廃液貯槽10と、高レベル放射性廃液の液相成分を蒸発させて高レベル放射性固体を生成する廃液固化装置20と、高レベル放射性固体をフッ素ガスと作用させて該高レベル放射性固体に含まれる分離対象の放射性核種を放射性核種フッ化物に転換する放射性核種フッ化装置30と、分離対象の放射性核種フッ化物を加熱して該核種フッ化物を揮発させて分離するフッ化物揮発分離装置40とを有する。フッ化物揮発分離装置40の下流に、分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化するフッ化物固化装置50を更に有していてもよい。 [First embodiment of the present invention]
(Radionuclide separation device and separation method)
FIG. 1 is a schematic diagram showing a configuration example of a radionuclide separation apparatus according to the present invention. As shown in FIG. 1, the radionuclide separation apparatus 100 of the present invention generates a high-level radioactive solid by evaporating a liquid phase component of a waste liquid storage tank 10 for storing a high-level radioactive waste liquid and a high-level radioactive waste liquid. Waste liquid solidification device 20, radionuclide fluorination device 30 that causes high-level radioactive solids to react with fluorine gas to convert the radionuclides to be separated contained in the high-level radioactive solids into radionuclide fluorides, and the radioactivity to be separated A fluoride volatilization separation device 40 that heats the nuclide fluoride to volatilize and separate the nuclide fluoride. A fluoride solidifying device 50 for cooling the volatile gas of the radionuclide fluoride to be separated and solidifying the nuclide fluoride may be further provided downstream of the fluoride volatile separation device 40.
　高レベル放射性廃液は、カチオン種として例えばセシウム（Cs）、ストロンチウム（Sr）、ジルコニウム（Zr）、パラジウム（Pd）、スズ（Sn）を含み、アニオン種として例えば硝酸イオン（NO3 －）を含む水溶液である。高レベル放射性廃液を安全・確実に収容することができるかぎり廃液貯槽10に特段の限定はなく、従前の廃液貯槽を利用できる。 The high-level radioactive liquid waste contains, for example, cesium (Cs), strontium (Sr), zirconium (Zr), palladium (Pd), tin (Sn) as the cationic species, and, for example, nitrate ions (NO 3 − ) as the anionic species. It is an aqueous solution. As long as high-level radioactive liquid waste can be stored safely and reliably, the liquid waste storage tank 10 is not particularly limited, and a conventional liquid waste storage tank can be used.
　なお、本発明においては、後述する放射性核種フッ化物揮発分離工程における熱処理温度を決定する上で、高レベル放射性廃液に含まれている放射性核種の種類、および該廃液中の分離対象の放射性核種の含有率（厳密にはモル分率）の情報が必要である。そのため、高レベル放射性廃液の組成が不明な場合には、高レベル放射性廃液に対して、カチオンの種類とモル分率とを少なくとも調査する廃液組成調査工程を行うことが好ましい。 In the present invention, in determining the heat treatment temperature in the radionuclide fluoride volatile separation step described later, the type of radionuclide contained in the high-level radioactive liquid waste and the radionuclide to be separated in the liquid waste are determined. Information on the content (strictly, the mole fraction) is required. Therefore, when the composition of the high-level radioactive liquid waste is unknown, it is preferable to perform a waste liquid composition investigation step that at least investigates the type and molar fraction of the cation with respect to the high-level radioactive liquid waste.
　廃液固化装置20は、高レベル放射性廃液中の液相成分を蒸発させて高レベル放射性固体（例えば、廃液中の放射性核種の酸化物粉末や硝酸塩粉末）を生成する放射性廃液固化工程を行う装置であり、液体を加熱できる機構を備えた廃液固化熱処理炉21（例えばロータリーキルン）と、熱処理温度を制御する廃液固化温度制御機構22とを有する。また、熱処理雰囲気を酸化性雰囲気（廃液中の放射性核種の酸化物を生成させるのに十分な酸素（O2）を含む雰囲気、例えば空気や酸素）に制御する廃液固化雰囲気制御機構23（例えば、ガス供給機構）を有することが好ましい。 The waste liquid solidification device 20 is a device that performs a radioactive waste liquid solidification process that evaporates liquid phase components in the high level radioactive waste liquid to generate high level radioactive solids (for example, radionuclide oxide powder and nitrate powder in the waste liquid). There is a waste liquid solidification heat treatment furnace 21 (for example, a rotary kiln) provided with a mechanism capable of heating a liquid, and a waste liquid solidification temperature control mechanism 22 for controlling the heat treatment temperature. Also, a waste liquid solidification atmosphere control mechanism 23 (for example, an atmosphere containing oxygen (O 2 ) sufficient to generate an oxide of a radionuclide in the waste liquid, for example, air or oxygen) is controlled. It is preferable to have a gas supply mechanism.
　放射性廃液固化工程の熱処理温度としては、廃液中の放射性核種の酸化物や硝酸塩等が生成する温度であり、かつ生成した酸化物や硝酸塩等が揮発しない温度が好ましい。例えば、400℃以上600℃以下が好ましく、450℃以上550℃以下がより好ましい。 The heat treatment temperature in the radioactive waste liquid solidification step is preferably a temperature at which oxides or nitrates of radionuclides in the waste liquid are generated and a temperature at which the generated oxides or nitrates are not volatilized. For example, it is preferably 400 ° C. or higher and 600 ° C. or lower, and more preferably 450 ° C. or higher and 550 ° C. or lower.
　放射性核種フッ化装置30は、高レベル放射性固体にフッ素ガスを作用させて該高レベル放射性固体に含まれる分離対象の放射性核種を放射性核種フッ化物に転換する放射性核種フッ化物転換工程を行う装置であり、加熱または冷却できる機構を備えたフッ化熱処理炉31（例えば流動層装置）と、熱処理温度を制御するフッ化温度制御機構32と、熱処理雰囲気をフッ素雰囲気に制御するフッ化雰囲気制御機構33（例えば、ガス供給機構や真空排気機構）とを有する。 The radionuclide fluorination device 30 is a device that performs a radionuclide fluoride conversion process in which fluorine gas is allowed to act on a high-level radioactive solid to convert the radionuclide to be separated contained in the high-level radioactive solid into a radionuclide fluoride. There is a fluorination heat treatment furnace 31 (for example, a fluidized bed apparatus) equipped with a mechanism capable of heating or cooling, a fluorination temperature control mechanism 32 for controlling the heat treatment temperature, and a fluorination atmosphere control mechanism 33 for controlling the heat treatment atmosphere to a fluorine atmosphere. (For example, a gas supply mechanism or a vacuum exhaust mechanism).
　放射性核種フッ化物転換工程の熱処理温度としては、フッ化反応が進行し、かつ分離対象の放射性核種のフッ化物が揮発しない温度が好ましく、例えば、200℃以上400℃未満が好ましい。 The heat treatment temperature in the radionuclide fluoride conversion step is preferably a temperature at which the fluorination reaction proceeds and the fluoride of the radionuclide to be separated does not volatilize, for example, 200 ° C. or more and less than 400 ° C.
　フッ化温度制御機構32では、フッ化反応の促進のために温度を高める制御を行う一方で、フッ化反応の進行に伴う反応熱によって望ましい温度範囲を超えそうな場合は、フッ化熱処理炉31を冷却する制御を行う。 In the fluorination temperature control mechanism 32, control is performed to increase the temperature in order to promote the fluorination reaction. On the other hand, if it is likely to exceed the desired temperature range due to the reaction heat accompanying the progress of the fluorination reaction, the fluorination heat treatment furnace 31 Control to cool down.
　なお、高レベル放射性廃液中に、分離対象の放射性核種のフッ化物よりも沸点が低いフッ化物を生成する元素（例えば、セレン（Se）やテルル（Te））が含まれている場合、該元素のフッ化物は、本工程中に揮発してフッ化熱処理炉31のオフガス配管（図示せず）より排出され、高レベル放射性固体から分離される。 In addition, if the high-level radioactive liquid waste contains an element (for example, selenium (Se) or tellurium (Te)) that generates a fluoride having a lower boiling point than the fluoride of the radionuclide to be separated, the element The fluoride is volatilized during this step and discharged from an off-gas pipe (not shown) of the fluorination heat treatment furnace 31 to be separated from the high-level radioactive solid.
　フッ化物揮発分離装置40は、分離対象の放射性核種フッ化物を加熱して該核種フッ化物を揮発させて分離する放射性核種フッ化物揮発分離工程を行う装置であり、炉内の温度プロファイルを制御できる機構を備えたフッ化物揮発熱処理炉41と、熱処理温度を制御するフッ化物揮発温度制御機構42と、キャリアガスを制御するキャリアガス制御機構43（例えば、ガス供給機構や真空排気機構）とを有する。 The fluoride volatilization separation device 40 is a device for performing a radionuclide fluoride volatilization separation process for heating and separating the radionuclide fluoride to be separated to volatilize and separate the nuclide fluoride, and the temperature profile in the furnace can be controlled. A fluoride volatilization heat treatment furnace 41 equipped with a mechanism, a fluoride volatilization temperature control mechanism 42 for controlling the heat treatment temperature, and a carrier gas control mechanism 43 (for example, a gas supply mechanism or a vacuum exhaust mechanism) for controlling the carrier gas .
　放射性核種フッ化物揮発分離工程の熱処理温度としては、分離対象の放射性核種フッ化物の飽和蒸気圧が、高レベル放射性固体中の該核種フッ化物の含有率から算出される分圧以上大気圧未満の蒸気圧となる温度が好ましい。例えば、500℃以上900℃以下が好ましい。 The heat treatment temperature of the radionuclide fluoride volatile separation step is such that the saturated vapor pressure of the radionuclide fluoride to be separated is not less than the partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than atmospheric pressure. The temperature at which the vapor pressure is reached is preferred. For example, it is preferably 500 ° C. or higher and 900 ° C. or lower.
　第１実施形態においては、フッ化物揮発温度制御機構42は、炉内全域がほぼ一定温度になるような制御を行う。加えて、所望の温度範囲内で徐々に昇温する制御を行うことがより好ましい。 In the first embodiment, the fluoride volatilization temperature control mechanism 42 performs control so that the entire temperature in the furnace becomes a substantially constant temperature. In addition, it is more preferable to perform control to gradually raise the temperature within a desired temperature range.
　キャリアガス制御機構43は、揮発したフッ化物ガスを効率よくフッ化物揮発熱処理炉41から排出する（すなわち、分離対象の放射性核種フッ化物を高レベル放射性固体から分離する）ために、フッ化物揮発熱処理炉41内にキャリアガスを流すための機構である。キャリアガスとしては、放射性核種フッ化物と化学反応しない不活性ガスが好ましく、例えば、窒素（N2）やアルゴン（Ar）を好ましく用いることができる。 The carrier gas control mechanism 43 efficiently discharges the volatilized fluoride gas from the fluoride volatilization heat treatment furnace 41 (that is, separates the radionuclide fluoride to be separated from the high-level radioactive solid) into a fluoride volatilization heat treatment. This is a mechanism for flowing a carrier gas into the furnace 41. As the carrier gas, an inert gas that does not chemically react with the radionuclide fluoride is preferable. For example, nitrogen (N 2 ) or argon (Ar) can be preferably used.
　図２は、セシウムフッ化物、ジルコニウムフッ化物およびスズフッ化物の飽和蒸気圧と温度との関係を示すグラフである。セシウムとジルコニウムとは分離対象の長半減期放射性核種である。スズは高レベル放射性廃液に含まれる元素であり、沸点の近さからジルコニウムに混合し易いとされる元素である。 FIG. 2 is a graph showing the relationship between saturated vapor pressure and temperature of cesium fluoride, zirconium fluoride and tin fluoride. Cesium and zirconium are long half-life radionuclides to be separated. Tin is an element contained in the high-level radioactive liquid waste, and is an element that can be easily mixed with zirconium because of its close boiling point.
　図２に示したように、沸点が近いフッ化物同士（ジルコニウムフッ化物、スズフッ化物）であっても飽和蒸気圧－温度曲線は大きく異なることが分かる。また、飽和蒸気圧は温度の上昇と共に急激に大きくなることが確認される。例えば、ジルコニウムフッ化物とスズフッ化物との飽和蒸気圧は、600℃において約２桁も差異があり、800℃でも約１桁の差異あることが分かる。本発明は、このような大きな飽和蒸気圧差を利用することによって、効率よく元素分離を行うものである。 As shown in FIG. 2, it can be seen that the saturation vapor pressure-temperature curves are greatly different even in the case of fluorides having close boiling points (zirconium fluoride, tin fluoride). Further, it is confirmed that the saturated vapor pressure increases rapidly as the temperature increases. For example, it can be seen that the saturation vapor pressures of zirconium fluoride and tin fluoride differ by about two orders of magnitude at 600 ° C., and differ by about one order of magnitude even at 800 ° C. In the present invention, element separation is efficiently performed by utilizing such a large saturated vapor pressure difference.
　図３Ａは、放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの一例である。図３Ｂは、図３Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。 FIG. 3A is an example of a set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. FIG. 3B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 3A.
　図３Ａに示したように、本実施形態でのフッ化物揮発熱処理炉41の炉内温度プロファイル（設定温度プロファイル）は、炉内全域で800℃の一定温度とした。図３Ｂは、「セシウムフッ化物：ジルコニウムフッ化物：スズフッ化物＝1：1：1」のモル比で混合した混合物の分離率変化を示したものである。 As shown in FIG. 3A, the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is a constant temperature of 800 ° C. throughout the furnace. FIG. 3B shows a change in the separation ratio of a mixture mixed at a molar ratio of “cesium fluoride: zirconium fluoride: tin fluoride = 1: 1: 1”.
　また、本発明においてフッ化物の分離率とは、フッ化物揮発熱処理炉41に投入した放射性核種フッ化物に対して、当該フッ化物が揮発して炉外に排出された比率（炉外に排出されたＡ元素のフッ化物／炉に投入したＡ元素のフッ化物）と定義する。すなわち、炉に投入したＡ元素のフッ化物の全量が炉外に排出された場合、「分離率＝1」となる。 In the present invention, the fluoride separation rate is the ratio of the fluoride volatilized and discharged to the outside of the furnace with respect to the radionuclide fluoride introduced into the fluoride volatilization heat treatment furnace 41 (discharged outside the furnace). Fluoride of element A / fluoride of element A charged in the furnace). That is, when the entire amount of the fluoride of element A charged in the furnace is discharged out of the furnace, “separation rate = 1”.
　図２に示したように、800℃における飽和蒸気圧は、スズフッ化物が最も高く、次にジルコニウムフッ化物、セシウムフッ化物の順に小さくなる。このため、フッ化物揮発熱処理炉42の炉内温度プロファイルを800℃で一定とした場合、図３Ｂに示したように飽和蒸気圧が最も高いスズフッ化物が最初に揮発して分離され（最も短時間で「分離率＝1」となり）、次にジルコニウムフッ化物、セシウムフッ化物の順で揮発・分離される。 As shown in FIG. 2, the saturated vapor pressure at 800 ° C. is highest for tin fluoride, and then decreases in the order of zirconium fluoride and cesium fluoride. Therefore, when the in-furnace temperature profile of the fluoride volatilization heat treatment furnace 42 is constant at 800 ° C., the tin fluoride having the highest saturated vapor pressure is volatilized first and separated (the shortest time) as shown in FIG. 3B. Then, "separation rate = 1"), and then volatilized and separated in the order of zirconium fluoride and cesium fluoride.
　なお、放射性核種フッ化物揮発分離工程において揮発しなかった放射性核種のフッ化物は、フッ化物揮発熱処理炉41内に在留し、別途回収することができる。 In addition, the radionuclide fluoride that has not volatilized in the radionuclide fluoride volatilization separation process resides in the fluoride volatilization heat treatment furnace 41 and can be collected separately.
　フッ化物固化装置50は、分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化する放射性核種フッ化物固化工程を行う装置であり、加熱または冷却できる機構を備えたフッ化物固化熱処理炉51と、熱処理温度を制御するフッ化物固化温度制御機構52とを有する。 The fluoride solidification device 50 is a device that performs a radionuclide fluoride solidification step of solidifying the radionuclide fluoride by cooling the volatile gas of the radionuclide fluoride to be separated, and is equipped with a mechanism that can be heated or cooled It has a solidification heat treatment furnace 51 and a fluoride solidification temperature control mechanism 52 for controlling the heat treatment temperature.
　放射性核種フッ化物固化工程の熱処理温度としては、前工程（放射性核種フッ化物揮発分離工程）でフッ化物揮発熱処理炉41から排出されたフッ化物ガスが確実に固化する温度であれば特段の限定はなく、例えば、200℃が好ましい。 The heat treatment temperature of the radionuclide fluoride solidification step is not particularly limited as long as the fluoride gas discharged from the fluoride volatilization heat treatment furnace 41 in the previous step (radionuclide fluoride volatilization separation step) is solidified surely. For example, 200 ° C. is preferable.
　また、フッ化物固化熱処理炉51は固体フッ化物回収容器51’を有しており、固体フッ化物回収容器51’が入れ替え容易な構造になっていることが好ましい。特に、カチオン種の異なるフッ化物ガスが時間差をもって排出されてくる場合、固体フッ化物回収容器51’が入れ替え容易な構造になっていれば、フッ化物ごとに固体フッ化物回収容器51’を替えることができ、放射性核種別の回収が容易になる。 Further, the fluoride solidification heat treatment furnace 51 has a solid fluoride recovery container 51 ', and it is preferable that the solid fluoride recovery container 51' has a structure that can be easily replaced. In particular, when fluoride gases of different cation species are discharged with a time difference, if the solid fluoride recovery container 51 ′ has a structure that can be easily replaced, the solid fluoride recovery container 51 ′ is replaced for each fluoride. This makes it easy to collect radionuclides.
　（第１実施形態の分離方法の変形例）
　放射性核種フッ化物揮発分離工程において、図３Ａのようにフッ化物揮発熱処理炉41の炉内温度プロファイルを炉内全域で一定温度とした上で、前述の温度範囲内（500～900℃）で徐々に昇温する熱処理は、より好ましい。 (Modification of the separation method of the first embodiment)
In the radionuclide fluoride volatilization separation step, the furnace temperature profile of the fluoride volatilization heat treatment furnace 41 is set to a constant temperature throughout the furnace as shown in FIG. 3A, and gradually within the above temperature range (500 to 900 ° C.). Heat treatment for raising the temperature to a higher value is more preferable.
　図２および図３Ｂの結果から考えると、スズフッ化物は500℃程度から揮発可能と考えられるが、ジルコニウムフッ化物およびセシウムフッ化物の揮発にはそれぞれ650℃程度および700℃程度の温度が必要と考えられる。そこで、熱処理温度を500℃から徐々に上げていくことにより、図３Ｂにおける各フッ化物の分離率の立ち上がり開始に十分な時間差をつくることができる。 2 and 3B, tin fluoride can be volatilized from about 500 ° C., but volatilization of zirconium fluoride and cesium fluoride requires temperatures of about 650 ° C. and 700 ° C., respectively. . Therefore, by gradually increasing the heat treatment temperature from 500 ° C., a sufficient time difference can be created for the start of rising of the separation rate of each fluoride in FIG. 3B.
　より具体的には、熱処理温度が500～650℃の間は実質的にスズフッ化物のみが揮発するので、スズ成分を選択的に分離することができる。その後、熱処理温度が650～700℃の間は実質的にジルコニウムフッ化物のみが揮発するので、ジルコニウム成分を選択的に分離することができる。その後、熱処理温度を更に上昇させていくと実質的にセシウムフッ化物のみが揮発するので、セシウム成分を選択的に分離することができる。この結果、各成分が混合する確率が減少するため、分離精度を向上させることができる。 More specifically, since only the tin fluoride is volatilized when the heat treatment temperature is 500 to 650 ° C., the tin component can be selectively separated. Thereafter, when the heat treatment temperature is 650 to 700 ° C., substantially only zirconium fluoride is volatilized, so that the zirconium component can be selectively separated. Thereafter, when the heat treatment temperature is further increased, only the cesium fluoride is substantially volatilized, so that the cesium component can be selectively separated. As a result, the probability of mixing each component decreases, so that the separation accuracy can be improved.
　以上説明したように、本実施形態によれば、分離したい放射性核種のフッ化物を沸点まで加熱する必要がなく、各フッ化物の飽和蒸気圧の差を利用することにより、各フッ化物の沸点未満の温度でもそれぞれの放射性核種を揮発分離することが可能になる。 As described above, according to this embodiment, it is not necessary to heat the fluoride of the radionuclide to be separated to the boiling point, and by utilizing the difference in the saturated vapor pressure of each fluoride, it is less than the boiling point of each fluoride. It becomes possible to volatilize and separate each radionuclide even at a temperature of.
　［本発明の第２実施形態］
　（放射性核種の分離方法）
　第２実施形態の分離方法は、放射性核種フッ化物揮発分離工程におけるフッ化物揮発熱処理炉41の炉内温度プロファイル（設定温度プロファイル）が第１実施形態のそれと異なっており、他を同じとするものである。そこで、放射性核種フッ化物揮発分離工程におけるフッ化物揮発熱処理炉41の炉内温度プロファイルについてのみ説明する。 [Second Embodiment of the Invention]
(Method for separating radionuclides)
In the separation method of the second embodiment, the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step is different from that of the first embodiment, and the others are the same. It is. Therefore, only the in-furnace temperature profile of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step will be described.
　図４Ａは、放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの他の一例である。図４Ｂは、図４Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。 FIG. 4A is another example of the set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. FIG. 4B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 4A.
　図４Ａに示したように、本実施形態でのフッ化物揮発熱処理炉41の炉内温度プロファイル（設定温度プロファイル）は、熱処理開始時にキャリアガス上流側（炉の入口側）の温度を900℃としキャリアガス下流側（炉の出口側）の温度を400℃として、キャリアガス上流側から下流側に向けてほぼ直線的に温度が低下するように設定したものであり、時間の経過と共にキャリアガス下流側（炉の出口側）の温度を徐々に上げて、最終的にキャリアガス下流側温度が900℃になるように制御したものである。図４Ｂは、先と同様に「セシウムフッ化物：ジルコニウムフッ化物：スズフッ化物＝1：1：1」のモル比で混合した混合物の分離率変化を示したものである。 As shown in FIG. 4A, the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is 900 ° C. at the carrier gas upstream side (furnace inlet side) at the start of heat treatment. The temperature on the downstream side of the carrier gas (furnace outlet side) is set to 400 ° C so that the temperature decreases almost linearly from the upstream side to the downstream side of the carrier gas. The temperature on the side (furnace outlet side) is gradually increased, and finally the temperature on the downstream side of the carrier gas is controlled to be 900 ° C. FIG. 4B shows the change in the separation rate of the mixture mixed at a molar ratio of “cesium fluoride: zirconium fluoride: tin fluoride = 1: 1: 1” as before.
　図４Ｂに示したように、スズフッ化物はキャリアガス下流側温度500℃程度から炉外に排出され始め、キャリアガス下流側温度約600℃でほぼ全量が炉外に排出される。この時、ジルコニウムフッ化物とセシウムフッ化物とは炉外にほとんど排出されておらず、フッ化物混合物からスズ成分をほぼ完全に分離できることが分かる。次に、キャリアガス下流側温度が600℃超になるとジルコニウムフッ化物とセシウムフッ化物とが炉外に排出され始めるが、それらの分離率の立ち上がり方（分離率変化の傾き）は大きく異なっていることが分かる。キャリアガス下流側温度約740℃でジルコニウムフッ化物は「分離率＝1」となるが、その時のセシウムフッ化物は「分離率≒0.2」である。その後、セシウムフッ化物はキャリアガス下流側温度約820℃で「分離率＝1」となる。 As shown in FIG. 4B, tin fluoride begins to be discharged out of the furnace at a carrier gas downstream temperature of about 500 ° C., and almost the entire amount is discharged out of the furnace at a carrier gas downstream temperature of about 600 ° C. At this time, it is understood that zirconium fluoride and cesium fluoride are hardly discharged outside the furnace, and the tin component can be almost completely separated from the fluoride mixture. Next, when the downstream temperature of the carrier gas exceeds 600 ° C, zirconium fluoride and cesium fluoride begin to be discharged out of the furnace, but their separation rate rises (gradient of change in separation rate) are greatly different. I understand. At a carrier gas downstream temperature of about 740 ° C., zirconium fluoride has a “separation rate = 1”, but the cesium fluoride at that time has a “separation rate≈0.2”. Thereafter, the cesium fluoride becomes “separation rate = 1” at a temperature downstream of the carrier gas of about 820 ° C.
　以上説明したように、本実施形態によれば、分離したい放射性核種のフッ化物を沸点まで加熱する必要がなく、各フッ化物の飽和蒸気圧の差を利用することにより、各フッ化物の沸点未満の温度でもそれぞれの放射性核種を揮発分離することが可能になる。 As described above, according to this embodiment, it is not necessary to heat the fluoride of the radionuclide to be separated to the boiling point, and by utilizing the difference in the saturated vapor pressure of each fluoride, it is less than the boiling point of each fluoride. It becomes possible to volatilize and separate each radionuclide even at a temperature of.
　［本発明の第３実施形態］
　（放射性核種の分離方法）
　第３実施形態の分離方法は、放射性核種フッ化物揮発分離工程におけるフッ化物揮発熱処理炉41の炉内温度プロファイル（設定温度プロファイル）が第１・第２実施形態のそれらと異なっており、他を同じとするものである。そこで、放射性核種フッ化物揮発分離工程におけるフッ化物揮発熱処理炉41の炉内温度プロファイルについてのみ説明する。 [Third embodiment of the present invention]
(Method for separating radionuclides)
In the separation method of the third embodiment, the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step is different from those of the first and second embodiments. It is the same thing. Therefore, only the in-furnace temperature profile of the fluoride volatilization heat treatment furnace 41 in the radionuclide fluoride volatilization separation step will be described.
　図５Ａは、放射性核種フッ化物揮発分離工程において、フッ化物揮発温度制御機構によって制御したフッ化物揮発熱処理炉の設定温度プロファイルの他の一例である。図５Ｂは、図５Ａの熱処理条件における熱処理時間とフッ化物の分離率との関係の一例を示すグラフである。 FIG. 5A is another example of the set temperature profile of the fluoride volatilization heat treatment furnace controlled by the fluoride volatilization temperature control mechanism in the radionuclide fluoride volatilization separation step. FIG. 5B is a graph showing an example of the relationship between the heat treatment time and the fluoride separation rate under the heat treatment conditions of FIG. 5A.
　図５Ａに示したように、本実施形態でのフッ化物揮発熱処理炉41の炉内温度プロファイル（設定温度プロファイル）は、熱処理開始時にキャリアガス上流端（炉の入口側）の温度を900℃としキャリアガス下流側（炉の出口側）の温度を700℃と固定して、キャリアガス上流側から下流側に向けてほぼ直線的に温度が低下するように設定したものである。図５Ｂは、「セシウムフッ化物：ジルコニウムフッ化物＝1：1」のモル比で混合した混合物の分離率変化を示したものである。 As shown in FIG. 5A, the in-furnace temperature profile (set temperature profile) of the fluoride volatilization heat treatment furnace 41 in this embodiment is set to 900 ° C. at the carrier gas upstream end (furnace inlet side) at the start of heat treatment. The temperature on the downstream side of the carrier gas (furnace outlet side) is fixed at 700 ° C., and is set so that the temperature decreases almost linearly from the upstream side to the downstream side of the carrier gas. FIG. 5B shows a change in separation rate of a mixture mixed at a molar ratio of “cesium fluoride: zirconium fluoride = 1: 1”.
　図５Ｂに示したように、熱処理開始後、ジルコニウムフッ化物およびセシウムフッ化物は共に炉外に排出され始めるが、それらの分離率の立ち上がり方（分離率変化の傾き）は両者で大きく異なっており、ジルコニウムフッ化物の方がより短時間で「分離率＝1」に到達することが分かる。この時のセシウムフッ化物は「分離率≒0.2」である。これは、炉外で回収するジルコニウムフッ化物には約17％のセシウムフッ化物が混入するが、炉内に残存するセシウムフッ化物にはジルコニウムフッ化物が混入していないことを意味する。なお、本工程を繰り返し行うことにより、ジルコニウム成分とセシウム成分との分離精度を向上させることができる。 As shown in FIG. 5B, after the heat treatment starts, both the zirconium fluoride and the cesium fluoride start to be discharged out of the furnace, but the rise of the separation rate (gradient of change in the separation rate) is greatly different between the two. It can be seen that zirconium fluoride reaches “separation rate = 1” in a shorter time. The cesium fluoride at this time has a “separation rate≈0.2”. This means that about 17% of cesium fluoride is mixed in the zirconium fluoride collected outside the furnace, but zirconium fluoride is not mixed in the cesium fluoride remaining in the furnace. In addition, the separation accuracy of the zirconium component and the cesium component can be improved by repeating this step.
　以上説明したように、本実施形態においても、分離したい放射性核種のフッ化物を沸点まで加熱する必要がなく、各フッ化物の飽和蒸気圧の差を利用することにより、各フッ化物の沸点未満の温度でもそれぞれの放射性核種を揮発分離することが可能になる。 As described above, also in this embodiment, it is not necessary to heat the fluoride of the radionuclide to be separated to the boiling point, and by utilizing the difference in the saturated vapor pressure of each fluoride, it is less than the boiling point of each fluoride. It is possible to volatilize and separate each radionuclide even at temperature.
　上述した実施形態は、本発明の理解を助けるために説明したものであり、本発明は、記載した具体的な構成のみに限定されるものではない。例えば、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。すなわち、本発明は、本明細書の実施形態の構成の一部について、削除・他の構成に置換・他の構成の追加をすることが可能である。 The above-described embodiments are described for helping understanding of the present invention, and the present invention is not limited only to the specific configurations described. For example, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. That is, according to the present invention, a part of the configuration of the embodiment of the present specification can be deleted, replaced with another configuration, or added with another configuration.
　100…放射性核種分離装置、10…廃液貯槽、20…廃液固化装置、21…廃液固化熱処理炉、22…廃液固化温度制御機構、23…廃液固化雰囲気制御機構、30…放射性核種フッ化装置、31…フッ化熱処理炉、32…フッ化温度制御機構、33…フッ化雰囲気制御機構、40…フッ化物揮発分離装置、41…フッ化物揮発熱処理炉、42…フッ化物揮発温度制御機構、43…キャリアガス制御機構、50…フッ化物固化装置、51…フッ化物固化熱処理炉、51’…固体フッ化物回収容器、52…フッ化物固化温度制御機構。 100 ... Radionuclide separation device, 10 ... Waste liquid storage tank, 20 ... Waste liquid solidification device, 21 ... Waste liquid solidification heat treatment furnace, 22 ... Waste liquid solidification temperature control mechanism, 23 ... Waste liquid solidification atmosphere control mechanism, 30 ... Radionuclide fluorination device, 31 ... Fluorine heat treatment furnace, 32 ... Fluoride temperature control mechanism, 33 ... Fluoride atmosphere control mechanism, 40 ... Fluoride volatilization separation device, 41 ... Fluoride volatilization heat treatment furnace, 42 ... Fluoride volatilization temperature control mechanism, 43 ... Carrier Gas control mechanism, 50 ... fluoride solidification device, 51 ... fluoride solidification heat treatment furnace, 51 '... solid fluoride recovery container, 52 ... fluoride solidification temperature control mechanism.

Claims (18)

  1. 　分離対象の放射性核種を含む高レベル放射性廃液から該分離対象の放射性核種を分離する方法であって、
    前記高レベル放射性廃液の液相成分を蒸発させて高レベル放射性固体を生成する放射性廃液固化工程と、
    前記高レベル放射性固体にフッ素ガスを作用させて該高レベル放射性固体に含まれる前記分離対象の放射性核種をフッ化物に転換する放射性核種フッ化物転換工程と、
    前記分離対象の放射性核種フッ化物の飽和蒸気圧が、前記高レベル放射性固体中の該核種フッ化物の含有率から算出される分圧以上大気圧未満の蒸気圧となる温度に加熱して該核種フッ化物を揮発させて分離する放射性核種フッ化物揮発分離工程とを有することを特徴とする放射性核種の分離方法。     A method for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated,
    A radioactive liquid waste solidifying step of evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid;
    A radionuclide fluoride conversion step in which fluorine gas is allowed to act on the high-level radioactive solid to convert the radionuclide to be separated contained in the high-level radioactive solid into fluoride;
    The saturated vapor pressure of the radionuclide fluoride to be separated is heated to a temperature at which the vapor pressure is equal to or higher than the partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than the atmospheric pressure. And a radionuclide fluoride volatilization separation step for volatilizing and separating the fluoride.
  2. 　請求項１に記載の放射性核種の分離方法において、
    前記分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化する放射性核種フッ化物固化工程を更に有することを特徴とする放射性核種の分離方法。     The method for separating radionuclides according to claim 1,
    A radionuclide separation method, further comprising a radionuclide fluoride solidifying step of cooling the volatile gas of the radionuclide fluoride to be separated to solidify the nuclide fluoride.
  3. 　請求項１又は請求項２に記載の放射性核種の分離方法において、
    前記放射性核種フッ化物揮発分離工程は、キャリアガスを流しながら行う500℃以上900℃以下の温度範囲の熱処理であることを特徴とする放射性核種の分離方法。     In the radionuclide separation method according to claim 1 or 2,
    The radionuclide fluoride volatile separation step is a heat treatment in a temperature range of 500 ° C. or higher and 900 ° C. or lower performed while flowing a carrier gas.
  4. 　請求項３に記載の放射性核種の分離方法において、
    前記放射性核種フッ化物揮発分離工程は、前記温度範囲内で徐々に昇温する熱処理であることを特徴とする放射性核種の分離方法。     The method for separating radionuclides according to claim 3,
    The radionuclide fluoride volatile separation step is a heat treatment in which the temperature is gradually raised within the temperature range, and the method for separating a radionuclide.
  5. 　請求項３に記載の放射性核種の分離方法において、
    前記放射性核種フッ化物揮発分離工程は、前記温度範囲内で前記キャリアガスの上流側の温度を高く、該キャリアガスの下流に向かって徐々に温度を低くする熱処理であることを特徴とする放射性核種の分離方法。     The method for separating radionuclides according to claim 3,
    The radionuclide fluoride volatile separation step is a heat treatment in which the temperature on the upstream side of the carrier gas is increased within the temperature range and the temperature is gradually decreased toward the downstream side of the carrier gas. Separation method.
  6. 　請求項５に記載の放射性核種の分離方法において、
    前記放射性核種フッ化物揮発分離工程は、前記キャリアガスの下流側の温度を前記温度範囲内で徐々に昇温する熱処理であることを特徴とする放射性核種の分離方法。     The radionuclide separation method according to claim 5,
    The radionuclide fluoride volatile separation step is a heat treatment in which the temperature on the downstream side of the carrier gas is gradually increased within the temperature range.
  7. 　請求項１乃至請求項６のいずれか一項に記載の放射性核種の分離方法において、
    前記分離対象の放射性核種は、スズ、ジルコニウムおよびセシウムの内の一つ以上であることを特徴とする放射性核種の分離方法。     In the radionuclide separation method according to any one of claims 1 to 6,
    The radionuclide separation method is characterized in that the radionuclide to be separated is one or more of tin, zirconium and cesium.
  8. 　請求項１乃至請求項７のいずれか一項に記載の放射性核種の分離方法において、
    前記放射性核種フッ化物転換工程は、400℃未満の温度範囲の熱処理であることを特徴とする放射性核種の分離方法。     In the radionuclide separation method according to any one of claims 1 to 7,
    The method for separating radionuclides, wherein the radionuclide fluoride conversion step is a heat treatment in a temperature range of less than 400 ° C.
  9. 　請求項１乃至請求項８のいずれか一項に記載の放射性核種の分離方法において、
    前記放射性廃液固化工程は、400℃以上600℃以下の温度範囲の熱処理であることを特徴とする放射性核種の分離方法。     In the radionuclide separation method according to any one of claims 1 to 8,
    The radionuclide separation method, wherein the radioactive liquid waste solidification step is a heat treatment in a temperature range of 400 ° C. or higher and 600 ° C. or lower.
  10. 　分離対象の放射性核種を含む高レベル放射性廃液から該分離対象の放射性核種を分離する分離装置であって、
    前記高レベル放射性廃液を収容する廃液貯槽と、
    前記高レベル放射性廃液の液相成分を蒸発させて高レベル放射性固体を生成する廃液固化装置と、
    前記高レベル放射性固体をフッ素ガスと作用させて該高レベル放射性固体に含まれる前記分離対象の放射性核種をフッ化物に転換する放射性核種フッ化装置と、
    キャリアガスを流しながら前記分離対象の放射性核種フッ化物を加熱して該核種フッ化物を揮発させて分離するフッ化物揮発分離装置とを有し、
    前記フッ化物揮発分離装置は、前記分離対象の放射性核種フッ化物の飽和蒸気圧が、前記高レベル放射性固体中の該核種フッ化物の含有率から算出される分圧以上大気圧未満の蒸気圧となる所定の温度範囲に制御するフッ化物揮発温度制御機構を有することを特徴とする放射性核種の分離装置。     A separation apparatus for separating a radionuclide to be separated from a high-level radioactive liquid waste containing the radionuclide to be separated,
    A waste liquid storage tank containing the high-level radioactive liquid waste;
    A waste liquid solidifying device for evaporating a liquid phase component of the high level radioactive liquid waste to produce a high level radioactive solid;
    A radionuclide fluorination apparatus that converts the radionuclide to be separated contained in the high-level radioactive solid into fluoride by allowing the high-level radioactive solid to act on fluorine gas;
    A fluoride volatilization separation device that heats the radionuclide fluoride to be separated while flowing a carrier gas to volatilize and separate the nuclide fluoride;
    The fluoride volatile separation device has a vapor pressure of a saturated vapor pressure of the radionuclide fluoride to be separated that is equal to or higher than a partial pressure calculated from the content of the nuclide fluoride in the high-level radioactive solid and less than atmospheric pressure. A radionuclide separation device having a fluoride volatilization temperature control mechanism for controlling to a predetermined temperature range.
  11. 　請求項１０に記載の放射性核種の分離装置において、
    前記分離対象の放射性核種フッ化物の揮発ガスを冷却して該核種フッ化物を固化するフッ化物固化装置を更に有することを特徴とする放射性核種の分離装置。     The radionuclide separation device according to claim 10,
    A radionuclide separation apparatus, further comprising a fluoride solidification device that cools the volatile gas of the radionuclide fluoride to be separated and solidifies the nuclide fluoride.
  12. 　請求項１０又は請求項１１に記載の放射性核種の分離装置において、
    前記フッ化物揮発温度制御機構は、500℃以上900℃以下の温度範囲に制御する機構であることを特徴とする放射性核種の分離装置。     The radionuclide separation device according to claim 10 or 11,
    The radionuclide separation apparatus, wherein the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature within a temperature range of 500 ° C to 900 ° C.
  13. 　請求項１２に記載の放射性核種の分離装置において、
    前記フッ化物揮発温度制御機構は、前記温度範囲で徐々に昇温するように制御する機構であることを特徴とする放射性核種の分離装置。     The radionuclide separation device according to claim 12,
    The radionuclide separation device is characterized in that the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature to gradually increase within the temperature range.
  14. 　請求項１２に記載の放射性核種の分離装置において、
    前記フッ化物揮発分離装置は、前記キャリアガスの上流側の温度を高く、該キャリアガスの下流に向かって徐々に温度が低くなる温度プロファイルを構築できる機構を有することを特徴とする放射性核種の分離装置。     The radionuclide separation device according to claim 12,
    The fluoride volatilization separation apparatus has a mechanism capable of constructing a temperature profile in which the temperature upstream of the carrier gas is increased and the temperature gradually decreases toward the downstream of the carrier gas. apparatus.
  15. 　請求項１４に記載の放射性核種の分離装置において、
    前記フッ化物揮発温度制御機構は、前記キャリアガスの下流側の温度を前記温度範囲内で徐々に昇温するように制御する機構であることを特徴とする放射性核種の分離装置。     The radionuclide separation device according to claim 14,
    The radionuclide separation device, wherein the fluoride volatilization temperature control mechanism is a mechanism for controlling the temperature on the downstream side of the carrier gas so as to gradually increase within the temperature range.
  16. 　請求項１０乃至請求項１５のいずれか一項に記載の放射性核種の分離装置において、
    前記分離対象の放射性核種は、スズ、ジルコニウムおよびセシウムの内の一つ以上であることを特徴とする放射性核種の分離装置。     The radionuclide separation device according to any one of claims 10 to 15,
    The radionuclide separation apparatus, wherein the radionuclide to be separated is one or more of tin, zirconium and cesium.
  17. 　請求項１０乃至請求項１６のいずれか一項に記載の放射性核種の分離装置において、
    前記放射性核種フッ化装置は、400℃未満の温度範囲に制御するフッ化温度制御機構を有することを特徴とする放射性核種の分離装置。     The radionuclide separation device according to any one of claims 10 to 16,
    The radionuclide fluorination device has a fluorination temperature control mechanism for controlling the temperature within a temperature range of less than 400 ° C.
  18. 　請求項１０乃至請求項１７のいずれか一項に記載の放射性核種の分離装置において、
    前記廃液固化装置は、400℃以上600℃以下の温度範囲に制御する廃液固化温度制御機構を有することを特徴とする放射性核種の分離装置。     The radionuclide separation device according to any one of claims 10 to 17,
    2. The radionuclide separation apparatus, wherein the waste liquid solidification apparatus has a waste liquid solidification temperature control mechanism for controlling the temperature within a temperature range of 400 ° C. to 600 ° C.
PCT/JP2016/065182 2016-05-23 2016-05-23 Radionuclide separation method and radionuclide separation device WO2017203567A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2018518818A JP6621917B2 (en) 2016-05-23 2016-05-23 Radionuclide separation method and radionuclide separation apparatus
PCT/JP2016/065182 WO2017203567A1 (en) 2016-05-23 2016-05-23 Radionuclide separation method and radionuclide separation device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2016/065182 WO2017203567A1 (en) 2016-05-23 2016-05-23 Radionuclide separation method and radionuclide separation device

Publications (1)

Publication Number Publication Date
WO2017203567A1 true WO2017203567A1 (en) 2017-11-30

Family

ID=60412204

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/065182 WO2017203567A1 (en) 2016-05-23 2016-05-23 Radionuclide separation method and radionuclide separation device

Country Status (2)

Country Link
JP (1) JP6621917B2 (en)
WO (1) WO2017203567A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112924267A (en) * 2019-12-06 2021-06-08 南京理工大学 Method for detecting nuclide volatilization ratio in evaporation and concentration process of simulated high-level radioactive waste liquid

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5684600A (en) * 1979-12-14 1981-07-09 Hitachi Ltd Method and device of decontaminating radioactive contaminant
JPH02201199A (en) * 1989-01-28 1990-08-09 Power Reactor & Nuclear Fuel Dev Corp Treatment of high-radioactive waste
JP2002357694A (en) * 2001-05-31 2002-12-13 Inst Of Research & Innovation Method for recovering zirconium from radioactive metal waste
JP2011179820A (en) * 2010-02-26 2011-09-15 Hitachi-Ge Nuclear Energy Ltd Method for waste adsorbent for fluoride
JP2013101066A (en) * 2011-11-09 2013-05-23 Hitachi-Ge Nuclear Energy Ltd Treatment device and treatment method for used fuel containing zirconium

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5684600A (en) * 1979-12-14 1981-07-09 Hitachi Ltd Method and device of decontaminating radioactive contaminant
JPH02201199A (en) * 1989-01-28 1990-08-09 Power Reactor & Nuclear Fuel Dev Corp Treatment of high-radioactive waste
JP2002357694A (en) * 2001-05-31 2002-12-13 Inst Of Research & Innovation Method for recovering zirconium from radioactive metal waste
JP2011179820A (en) * 2010-02-26 2011-09-15 Hitachi-Ge Nuclear Energy Ltd Method for waste adsorbent for fluoride
JP2013101066A (en) * 2011-11-09 2013-05-23 Hitachi-Ge Nuclear Energy Ltd Treatment device and treatment method for used fuel containing zirconium

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112924267A (en) * 2019-12-06 2021-06-08 南京理工大学 Method for detecting nuclide volatilization ratio in evaporation and concentration process of simulated high-level radioactive waste liquid

Also Published As

Publication number Publication date
JP6621917B2 (en) 2019-12-18
JPWO2017203567A1 (en) 2019-02-14

Similar Documents

Publication Publication Date Title
US20060057042A1 (en) Reprocessing method by fluoride volatility process using fractional distillation
US7172741B2 (en) Method for reprocessing spent nuclear fuel
US8867692B2 (en) Systems and methods for treating material
JP6621917B2 (en) Radionuclide separation method and radionuclide separation apparatus
JP2014532855A (en) Thermal decontamination of graphite with reducing gas.
CN113795894B (en) Spent fuel dry post-treatment method based on plasma
US5774815A (en) Dry halide method for separating the components of spent nuclear fuels
JP3823593B2 (en) Method for reprocessing spent nuclear fuel and method for reprocessing spent nuclear fuel
Yang et al. An efficient capture of cesium from cesium iodide (CsI) off-gas by aluminosilicate sorbents in the presence of oxygen
JP2551879B2 (en) Reduction method of vitrification of highly radioactive waste
JP6253046B2 (en) Cesium extraction method
KR101369123B1 (en) Method for separation of group Ⅱ nuclides and recovery of pure LiCl by using Li2O
JP2006046967A (en) Reprocessing method by fluoride volatilization method using solid-gas separation method
JP7041642B2 (en) Fuel debris sorting device and sorting method
JP2020204518A (en) Method for separating lanthanoid from radioactive solution
JP2012047546A (en) Fluorination device, fluorination method and reprocessing method for nuclear fuel material
JP6638071B2 (en) Zirconium separation method and spent fuel treatment method
JP6513909B2 (en) Radionuclide separation method for vitrified material
JP2002071865A (en) Manufacturing method for mixed oxide fuel for nuclear reactor
JP2813551B2 (en) Extraction and separation of metal elements using supercritical fluid as medium
JP2018063198A (en) Separation method and separation device of minor actinoid
JP6515369B1 (en) Insoluble residue treatment process
JP2009294145A (en) Recycling method of uranium from spent nuclear fuel
JPH1026696A (en) Method for plasma melting treatment of radioactive solid waste and facility used for such method
JP2024049151A (en) High-level radioactive substance processing system and high-level radioactive substance processing method

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2018518818

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16903049

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 16903049

Country of ref document: EP

Kind code of ref document: A1