JP3580597B2 - Treatment of radioactive aluminum waste - Google Patents
Treatment of radioactive aluminum waste Download PDFInfo
- Publication number
- JP3580597B2 JP3580597B2 JP06815495A JP6815495A JP3580597B2 JP 3580597 B2 JP3580597 B2 JP 3580597B2 JP 06815495 A JP06815495 A JP 06815495A JP 6815495 A JP6815495 A JP 6815495A JP 3580597 B2 JP3580597 B2 JP 3580597B2
- Authority
- JP
- Japan
- Prior art keywords
- aluminum
- radioactive
- waste
- alloy
- content
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Lifetime
Links
Images
Landscapes
- Processing Of Solid Wastes (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は、原子力施設等において発生する放射性アルミニウム廃棄物の処理方法に関するものである。
【０００２】
【従来の技術】
原子力施設等から発生する放射性雑固体廃棄物の中には、ＨＥＰＡフィルタのアルミニウムセパレータ、アルミニウム製足場材などの放射性アルミニウム廃棄物が含まれている。
【０００３】
金属、コンクリート、保温材などの放射性雑固体廃棄物は、そのままあるいは切断／圧縮処理した後に２００ リットルドラム缶に入れ、モルタルを充填した廃棄体とする方法と、溶融処理した後に２００ リットルドラム缶に入れ、モルタルを充填して廃棄体とする方法が検討されており、その廃棄体は埋設処分することが検討されている。ところが放射性雑固体廃棄物にはアルミニウム廃棄物があり、これはモルタル固化した時や廃棄体として埋設処分時にモルタルまたはコンクリート等と接触してアルカリ性となった地下水と接触して次式に示す反応等により水素ガスを発生する。
【０００４】
【化１】
６Ａｌ ＋３Ｃａ（ＯＨ）２＋６Ｈ２Ｏ→３ＣａＯ・Ａｌ２Ｏ３ ＋９Ｈ２ ↑
【０００５】
この反応によれば、１ｇのアルミニウムから２０℃で約１３５０ｍｌの水素ガスが発生することとなり、健全な廃棄体ができなかったり、埋設施設の安全評価上、問題となるおそれがある。従って放射性アルミニウム廃棄物は放射性雑固体廃棄物から除去し、他の廃棄物のように埋設処分を行うことができないと考えられていた。また箔状の放射性アルミニウム廃棄物を含むＨＥＰＡフィルタに関しては、特開平４−２９０９９７号公報に示すように「Ａｌセパレータ、ガラス織組濾布からなるＨＥＰＡフィルタを切断前処理の後、ガラス化添加材とともに溶融し、ＨＥＰＡフィルタ中のＡｌセパレータをガラス化して固化する方法」があるが、放射性廃棄物の他にガラス化添加材を加えるため、放射性廃棄物のみを溶融処理するときより減容性が劣っていた。
【０００６】
【発明が解決しようとする課題】
本発明は上記した従来の問題点を解決して、他の放射性雑固体廃棄物と同様に、放射性アルミニウム廃棄物を埋設処分するうえでの支障がなくなるようにすることができ、加えて箔状の放射性アルミニウム廃棄物に関しては減容性を改善した放射性アルミニウム廃棄物の処理方法を提供するためになされたものである。
【０００７】
【課題を解決するための手段】
上記の課題を解決するためになされた本発明は、塊状の放射性アルミニウム廃棄物を鉄系金属とともに混合溶融処理することにより、水と接触して水素ガスの発生の少ないＡｌ含有率８０％以下のＦｅ−Ａｌ合金とすることを特徴とするものである。また、本発明では前記Ｆｅ−Ａｌ合金のＡｌ含有率を２０％以下とするのが特に好ましい。
【０００８】
【作用】
本発明によれば、塊状の放射性アルミニウム廃棄物を鉄系金属とともに混合溶融処理することにより水と接触して水素ガスの発生の少ないＡｌ含有率８０％以下のFe−Al合金とするが、このFe−Al合金のガス発生速度はアルミニウムの含有率に依存し、含有率を２０％以下とすれば炭素鋼と同等のガス発生速度とすることができる。また、箔状の放射性アルミニウム廃棄物を保温材等の無機廃棄物とともに溶融処理することによりアルミニウムをAl２O３ とし、他の無機廃棄物とともに安定なセラミック層を形成すれば、モルタル固化した時やアルカリ性水溶液と接触しても水素ガス発生のおそれがない。なお、箔状のアルミニウムの溶融はアルミニウム（融点660 ℃) がAl２O３ （融点約2000℃) となることにより融点が高くなるため、ともに溶融する無機廃棄物はAl２O３ の融点を降下させるような成分の廃棄物を用いる必要があり、一例として、SiO２、CaO を主成分とするけい酸カルシウム保温材を用いることができる。従ってこれらによれば、放射性アルミニウム廃棄物を他の放射性雑固体廃棄物と同様に埋設処分することができ、加えて箔状の放射性アルミニウム廃棄物に関しては減容性を改善することが可能となる。
【０００９】
【実施例】
以下に本発明を図示の実施例によって更に詳細に説明する。
〔実施例１〕原子力施設等から発生する放射性雑固体廃棄物のうち、足場材等として使用される塊状のアルミニウムを、鉄系金属とともに溶融する。溶融炉については対象物が合金化する温度を確保できればよく、誘導炉やアーク炉等の電気炉あるいはガス式のガラス炉等を適宜に選択できる。合金化するための温度の指標となるＦｅ−Ａｌ 系の状態図を図１に示す。アルミニウムの融点は６６０ ℃であるため、塊状のアルミニウムは容易に溶融し、鉄系金属と混合溶融処理されたＦｅ−Ａｌ合金となる。このとき、アルミニウムと鉄系金属（炭素鋼）との混合比率を変えたサンプルを作成し、温度１０℃のコンクリート平衡水と接触させてガス発生量を測定した。その結果を図２に示す。なお、図２の縦軸はガス発生量の累積値である。
【００１０】
図２から明らかなように、Ｆｅ−Ａｌ合金中のアルミニウムの含有率を２０％以下とした場合には、ガス発生速度は炭素鋼とほぼ同じレベルであった。また、アルミニウムの含有率を４０〜８０％としたときは、ガス発生量は初期に大きい値を示すものの、２０日経過後は抑制されることが確認された。
【００１１】
次にコンクリート平衡水の温度を４０℃とした場合のグラフを図３に示す。この場合においても、アルミニウムの含有率を２０％以下とした場合にはガス発生速度は炭素鋼とほぼ同じレベルであった。また、アルミニウムの含有率を４０〜８０％としたときは、ガス発生量は初期に大きい値を示すものの、２０日経過後は抑制されることが確認された。このように、アルミニウムの含有率を２０％以下とすれば炭素鋼と同様にガス発生量をきわめて低いレベルに押さえることができ、またアルミニウムの含有率が４０〜８０％程度でもガス発生量をアルミニウム金属より抑制できることを確認した。
【００１２】
このようにして得られたＦｅ−Ａｌ合金は、例えば図４に示されるような形態でドラム缶１の内部に収納される。図４において２はるつぼ、３はＦｅ−Ａｌ合金層、４はセラミック層、５はモルタル、６は蓋である。この状態の廃棄体は地中のピット内に埋設処分されるが、水素ガスの発生が抑制され、埋設施設の安全評価上の問題がなくなる可能性がある。
【００１３】
〔参考例〕原子力発電所等から排出される放射性雑固体廃棄物のうち、箔状のアルミニウムセパレータ（厚さ数十μm ）を含むＨＥＰＡフィルタを保温材等とともに溶融する。溶融炉については、対象物を溶融する温度が確保できればよく、前述の電気炉あるいはガス式のガラス炉等を適宜に選択できる。その結果、アルミニウムセパレータは酸化されてAl２O３ となり、他の無機廃棄物（金属以外）とともに安定なセラミック層を形成した。これをアルカリ性水溶液と接触させても水素ガスの発生は皆無であり、埋設処分するに支障のないことを確認した。
【００１４】
【発明の効果】
以上に説明したように、本発明によれば原子力施設等において発生する塊状の放射性アルミニウム廃棄物を他の雑固体廃棄物と同様に埋設処分するのに支障がない。また、箔状の放射性アルミニウム廃棄物に関してはガラス化添加材の代わりに例えば保温材を使用することにより安定なセラミック層を形成でき、減容性が改善できる。このため、従来考えられていたように放射性アルミニウム廃棄物を分離してそのまま保管する必要がなくなる利点がある。
【図面の簡単な説明】
【図１】Ｆｅ−Ａｌ系の状態図である。
【図２】Ｆｅ−Ａｌ合金を、温度１０℃のコンクリート平衡水と接触させてガス発生量を測定した結果を示すグラフである。
【図３】Ｆｅ−Ａｌ合金を、温度４０℃のコンクリート平衡水と接触させてガス発生量を測定した結果を示すグラフである。
【図４】廃棄体の断面図である。
【符号の説明】
１ ドラム缶、２ るつぼ、３ Ｆｅ−Ａｌ合金層、４ セラミック層、５ モルタル、６ 蓋[0001]
[Industrial applications]
The present invention relates to a method for treating radioactive aluminum waste generated in a nuclear facility or the like.
[0002]
[Prior art]
Radioactive miscellaneous solid waste generated from nuclear facilities and the like includes radioactive aluminum waste such as aluminum separators of HEPA filters and aluminum scaffolds.
[0003]
Radioactive miscellaneous solid waste, such as metal, concrete, and heat insulation, is placed in a 200-liter drum can as it is or cut / compressed and then placed in a 200-liter drum after mortar filling. A method of filling the mortar into a waste body is being studied, and the disposal of the waste body is being studied. However, radioactive miscellaneous solid waste includes aluminum waste, which is contacted with mortar or concrete, etc. during mortar solidification or disposal as landfill and becomes alkaline with groundwater, and reacts as shown in the following formula. Generates hydrogen gas.
[0004]
Embedded image
6Al + 3Ca (OH) 2 + 6H 2 O → 3CaO · Al 2
[0005]
According to this reaction, about 1350 ml of hydrogen gas is generated from 1 g of aluminum at 20 ° C., and there is a possibility that a sound waste body cannot be formed or a problem occurs in the safety evaluation of a buried facility. Therefore, it was thought that radioactive aluminum waste could not be removed from radioactive miscellaneous solid waste and buried as in other wastes. As for the HEPA filter containing radioactive aluminum waste in the form of foil, as described in Japanese Patent Application Laid-Open No. 290997/1992, "HEPA filter composed of Al separator and glass woven filter cloth is subjected to pre-cutting treatment, And solidify by vitrifying the Al separator in the HEPA filter ". However, since the vitrification additive is added in addition to the radioactive waste, the volume reduction is smaller than when only the radioactive waste is melt-processed. Was inferior.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems and, like other radioactive miscellaneous solid wastes, can eliminate the problem of disposing radioactive aluminum waste by burying it. The present invention has been made to provide a method for treating radioactive aluminum waste with improved volume reduction.
[0007]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problem. By mixing and melting a massive radioactive aluminum waste together with an iron-based metal, an Al content of 80% or less, which is in contact with water and generates little hydrogen gas. It is characterized by using an Fe-Al alloy . In the present invention, it is particularly preferable that the Al content of the Fe—Al alloy is 20% or less.
[0008]
[Action]
According to the present invention, a mass of radioactive aluminum waste is mixed and melted with an iron-based metal to make contact with water to produce a Fe—Al alloy having an Al content of 80% or less, which generates less hydrogen gas. The gas generation rate of the Fe-Al alloy depends on the aluminum content, and if the content is 20% or less, the gas generation rate can be made equivalent to that of carbon steel. Also, aluminum and Al 2 O 3 by melt processing with inorganic wastes such as heat insulating material a foil-like radioactive aluminum waste lever to form stable ceramic layer together with other inorganic wastes, mortar solidifies There is no danger of generating hydrogen gas even when contacting with an alkaline aqueous solution. In addition, the melting of foil-shaped aluminum increases as aluminum (melting point 660 ° C.) becomes Al 2 O 3 (melting point of about 2000 ° C.), so that the inorganic waste that melts together has a melting point of Al 2 O 3 . It is necessary to use a waste of a component that causes a drop. For example, a calcium silicate heat insulator containing SiO 2 and CaO as main components can be used. Therefore, according to these, it is possible to radioactive aluminum wastes as well as other radioactive miscellaneous solid waste disposal disposal, can improve the volume reduction of the terms foil radioactive aluminum wastes in addition the Become.
[0009]
【Example】
Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments.
[Example 1] Among radioactive miscellaneous solid waste generated from a nuclear facility or the like, massive aluminum used as a scaffold or the like is melted together with an iron-based metal. As long as the temperature at which the object is alloyed can be ensured for the melting furnace, an electric furnace such as an induction furnace or an arc furnace, or a gas-type glass furnace can be appropriately selected. FIG. 1 shows a phase diagram of an Fe-Al 2 -based alloy serving as an index of the temperature for alloying. Since aluminum has a melting point of 660 ° C., lump aluminum is easily melted to form an Fe—Al alloy mixed and melted with an iron-based metal. At this time, a sample was prepared in which the mixing ratio of aluminum and iron-based metal (carbon steel) was changed, and the sample was brought into contact with concrete equilibrium water at a temperature of 10 ° C. to measure the gas generation amount. The result is shown in FIG. Note that the vertical axis in FIG. 2 is the cumulative value of the gas generation amount.
[0010]
As is clear from FIG. 2, when the content of aluminum in the Fe-Al alloy was set to 20% or less, the gas generation rate was almost the same level as that of carbon steel. When the content of aluminum was set to 40 to 80%, it was confirmed that the gas generation amount was initially large, but was suppressed after 20 days.
[0011]
Next, FIG. 3 shows a graph when the temperature of the concrete equilibrium water is set to 40 ° C. Also in this case, when the content of aluminum was set to 20% or less, the gas generation rate was almost the same level as that of carbon steel. When the content of aluminum was set to 40 to 80%, it was confirmed that the gas generation amount was initially large, but was suppressed after 20 days. As described above, when the content of aluminum is set to 20% or less, the gas generation amount can be suppressed to an extremely low level as in the case of carbon steel, and even when the aluminum content is about 40 to 80%, the gas generation amount is reduced to aluminum. It was confirmed that it could be suppressed more than metal.
[0012]
The Fe—Al alloy thus obtained is housed inside the
[0013]
[ Reference Example ] Among radioactive miscellaneous solid wastes discharged from a nuclear power plant or the like, a HEPA filter containing a foil-shaped aluminum separator (thickness of several tens of μm) is melted together with a heat insulating material and the like. As for the melting furnace, it is sufficient that the temperature at which the object is melted can be ensured, and the above-described electric furnace or gas-type glass furnace can be appropriately selected. As a result, the aluminum separator was oxidized to Al 2 O 3 and formed a stable ceramic layer together with other inorganic wastes (other than metals). It was confirmed that there was no generation of hydrogen gas even when this was brought into contact with an alkaline aqueous solution, and that there was no problem in burying and disposal.
[0014]
【The invention's effect】
As described above, there is no hindrance to similarly disposed underground and lumps form radioactive aluminum waste that occur in nuclear facilities other miscellaneous solid wastes according to the present invention. Further, with respect to the foil-shaped radioactive aluminum waste, a stable ceramic layer can be formed by using, for example, a heat insulating material instead of the vitrification additive, and the volume reduction can be improved. Therefore, by separating the conventional thought and radioactive aluminum wastes as had should have a Ru kuna advantage to store it.
[Brief description of the drawings]
FIG. 1 is a state diagram of an Fe—Al system.
FIG. 2 is a graph showing a result of measuring a gas generation amount by bringing an Fe—Al alloy into contact with concrete equilibrium water at a temperature of 10 ° C.
FIG. 3 is a graph showing a result of measuring a gas generation amount by bringing an Fe—Al alloy into contact with concrete equilibrium water at a temperature of 40 ° C.
FIG. 4 is a sectional view of a waste body.
[Explanation of symbols]
1 Drum can, 2 crucible, 3 Fe-Al alloy layer, 4 ceramic layer, 5 mortar, 6 lid
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06815495A JP3580597B2 (en) | 1995-03-27 | 1995-03-27 | Treatment of radioactive aluminum waste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06815495A JP3580597B2 (en) | 1995-03-27 | 1995-03-27 | Treatment of radioactive aluminum waste |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08262192A JPH08262192A (en) | 1996-10-11 |
| JP3580597B2 true JP3580597B2 (en) | 2004-10-27 |
Family
ID=13365551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06815495A Expired - Lifetime JP3580597B2 (en) | 1995-03-27 | 1995-03-27 | Treatment of radioactive aluminum waste |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3580597B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1737993B1 (en) * | 2004-04-22 | 2010-08-11 | Alcan International Limited | Improved recycling method for al-b, c composite materials |
-
1995
- 1995-03-27 JP JP06815495A patent/JP3580597B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08262192A (en) | 1996-10-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5662579A (en) | Vitrification of organics-containing wastes | |
| US4988376A (en) | Glassification of lead and silica solid waste | |
| US5731564A (en) | Method of operating a centrifugal plasma arc furnace | |
| Wang et al. | Melting of municipal solid waste incinerator fly ash by waste-derived thermite reaction | |
| JPH03264898A (en) | Treatment of high level radioactive wastes | |
| US2950962A (en) | Reduction of fluoride to metal | |
| JP3580597B2 (en) | Treatment of radioactive aluminum waste | |
| JPH03123896A (en) | Recovery of actinides | |
| JP2551879B2 (en) | Reduction method of vitrification of highly radioactive waste | |
| RU2159473C1 (en) | Method for recovering radionuclide-containing metal wastes | |
| JP4067601B2 (en) | Waste disposal body, manufacturing method thereof, and manufacturing apparatus thereof | |
| JP2818253B2 (en) | Dissolution method of iron-based scrap contaminated with radioactive materials | |
| JP3732561B2 (en) | Simultaneous implementation of iron alloy production and incineration ash melting in an electric furnace | |
| JPH09227962A (en) | Alloy by recovering valuable metal from municipal refuse and its recovering method | |
| JP2996659B1 (en) | Contaminated soil treatment method and block material obtained using contaminated soil | |
| JPH11104593A (en) | Fusing treatment of incineration ash | |
| Uda et al. | A melt refining method for uranium-contaminated aluminum | |
| JP3858369B2 (en) | Zirconium alloy waste decontamination method and apparatus | |
| JPS60165326A (en) | Treatment of dust containing heavy metal chloride | |
| Buckentin | Melt decontamination of radioactive stainless steel by electroslag remelting | |
| Johnson et al. | Proposed methods for treating high-level pyrochemical process wastes.[Integral Fast Reactor] | |
| RU2112058C1 (en) | Apparatus for metallothermic reduction of metal halides | |
| Min et al. | Partitioning ratio of depleted uranium during a melt decontamination by arc melting | |
| Schulz et al. | Solidification and storage of Hanford's high-level radioactive liquid wastes | |
| JPH0136919B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20040716 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20040720 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080730 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090730 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100730 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100730 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110730 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120730 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120730 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130730 Year of fee payment: 9 |
|
| EXPY | Cancellation because of completion of term |