JPH0119560B2 - - Google Patents
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- Publication number
- JPH0119560B2 JPH0119560B2 JP57028563A JP2856382A JPH0119560B2 JP H0119560 B2 JPH0119560 B2 JP H0119560B2 JP 57028563 A JP57028563 A JP 57028563A JP 2856382 A JP2856382 A JP 2856382A JP H0119560 B2 JPH0119560 B2 JP H0119560B2
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- container
- porous sintered
- radioactive waste
- solidified
- 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
Links
- 229910052751 metal Inorganic materials 0.000 claims description 38
- 239000002184 metal Substances 0.000 claims description 38
- 239000002901 radioactive waste Substances 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 26
- 239000000919 ceramic Substances 0.000 claims description 15
- 238000010304 firing Methods 0.000 claims description 14
- 239000000126 substance Substances 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000005470 impregnation Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 239000011148 porous material Substances 0.000 claims description 2
- 238000003860 storage Methods 0.000 description 22
- 239000000463 material Substances 0.000 description 14
- 229910045601 alloy Inorganic materials 0.000 description 9
- 239000000956 alloy Substances 0.000 description 9
- 229910052802 copper Inorganic materials 0.000 description 7
- 238000007711 solidification Methods 0.000 description 7
- 230000008023 solidification Effects 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- 239000002699 waste material Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 229910052725 zinc Inorganic materials 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 230000007774 longterm Effects 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- 229910052726 zirconium Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 230000017525 heat dissipation Effects 0.000 description 3
- 238000002386 leaching Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000012857 radioactive material Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 229910052718 tin Inorganic materials 0.000 description 3
- 229910017518 Cu Zn Inorganic materials 0.000 description 2
- 229910017752 Cu-Zn Inorganic materials 0.000 description 2
- 229910017943 Cu—Zn Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000009933 burial Methods 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000012958 reprocessing Methods 0.000 description 2
- 239000002915 spent fuel radioactive waste Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Inorganic materials [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 239000002925 low-level radioactive waste Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000005258 radioactive decay Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000000941 radioactive substance Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Inorganic materials [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Description
〔発明の技術分野〕
本発明は、放射性廃棄物の処理方法に関し、さ
らに詳しくは、放射性廃棄物か焼体とセラミツク
形成物質の混合粉末を成形後、加熱焼成によつて
形成される多孔質焼結体に溶融金属を含浸させる
ことによつて、化学的、機械的に安定で半永久的
貯蔵に適した放射性廃棄物貯蔵体を製造する方法
に関する。
〔発明の技術的背景〕
原子力発電の普及にともない使用済核燃料の再
処理工場から発生する高濃度の放射性廃液は、年
年増大する傾向にあり、これらの放射性廃液を液
状のままでタンク貯蔵することには安全上の問題
があるため、より安全に保管できる固形貯蔵体へ
の変換技術の確立が切望されている。
一般に放射性廃棄物の処分に際しては、放射性
物質の周囲への拡散が最小限となる形態に廃棄物
を固形化し、得られた固形貯蔵体が、化学的、機
械的に安定していて、長期の貯蔵によつても環境
汚染の原因にならないことが必要である。このよ
うな観点で現在までに提案されている固形化方法
としてセラミツク固化法（たとえば特開昭55−
12447号、同55−12448号、同55−87100号、同55
−90463号各公報に記載のもの等）がある。この
方法は、放射性廃棄物のか焼体に、例えばアルミ
ナ、シリカ、チタニア等のセラミツク形成物質を
適当量添加し、圧縮成形後、加熱焼成することに
より一定形状のセラミツクス固化体を製造するも
のである。
〔背景技術の問題点〕
上述したような従来のセラミツク固化法によれ
ば、通常1200℃以上の高温で焼成することによ
り、比較的機械的強度も大きく緻密で耐水性にす
ぐれた焼結体を得ることができるが、以下のよう
な問題を有する。
(イ) 一般に焼成温度は低いほど固化体の製造は容
易であり、また炉等の焼成装置類への負担の低
減の点で有利である。そのため1200℃以下の比
較的低温において焼結体を形成できることが望
ましい。ところが、本発明者らの研究によれ
ば、従来公表されているセラミツク形成物質の
組成範囲では、1200℃以下の温度で焼成を行な
うと、機械的に弱い、多孔質の焼結体しか得ら
れなかつた。
(ロ) セラミツク固化体は、機械的衝撃に弱く、固
化体の貯蔵容器が破損した場合を想定すると、
該固化体は外部の雰囲気、例えば地中貯蔵の場
合は地下水などと直接接することになるため、
水などの外部雰囲気に対する放射性物質の浸出
率を可能な限り少なくすることが要請される。
(ハ) セラミツク固化体は熱伝導性が本質的に小さ
いため、固化体中に含まれる放射性物質の放射
性崩壊に伴なつて発生する熱の放散が不充分と
なる。そのため、固化体内部の温度上昇による
内部の変質、高輝発性物質の外部への逸出を促
すという問題が生じ、長期にわたる放射性廃棄
物の安全な貯蔵を困難にする。
〔発明の目的〕
本発明は、上述したような従来のセラミツク固
化法の欠点を除くものであり、機械的強度、化学
的安定性および熱放散性にすぐれ、長期にわたり
安全に貯蔵し得るような放射性廃棄物貯蔵体の製
造法を提供することを目的とする。
〔発明の概要〕
本発明者らの研究によれば、放射性廃棄物のか
焼体とセラミツク形成物質の混合物を、1200℃以
下の比較的低温において焼成することによつて得
られる多孔質焼結体を溶融金属に含浸し固化する
ことにより、従来のセラミツク固化体に比べ機械
的強度、熱放散性にすぐれた放射性廃棄物貯蔵体
が得られることが見出された。すなわち、本発明
の放射性廃棄物の処理方法は、か焼した放射性廃
棄物20〜40重量％とセラミツク形成物質80〜60重
量％とを混合し成形した後900〜1100℃の温度で
加熱焼成し多孔質焼結体を形成する工程と、該多
孔質焼結体を容器に装入し、該容器中で溶融金属
を前記多孔質焼結体に含浸させ固化させる工程か
らなることを特徴とするものである。
〔発明の具体的説明〕
以下、本発明を更に詳細に説明する。以下の記
載において、「部」および「％」は特に断らない
限り重量基準とする。
本発明の処理対象となる放射性廃棄物として
は、例えば使用済核燃料を処理した後、Ｕ、Pu
を回収した残りの放射性廃棄物の他、混床式脱塩
器の再生廃液の濃縮液、建屋から発生する床ドレ
インあるいは機器ドレインの濃縮廃液などの放射
性物質を含む各種の廃液、更には原子水浄化
系、燃料プール系、復水系、ドレイン系の各系統
から生ずる使用済イオン交換樹脂、フイルタース
ラツジ、廃液の凝集沈殿処理によつて生ずる沈殿
スラツジなどの各種の固体廃棄物など、高レベル
および中低レベルの放射性廃棄物が含まれる。こ
れら放射性廃棄物をか焼することにより、原料と
してのか焼体が得られる。一方、セラミツク形成
物質としてはAl2O3、SiO2、BaO、SrO、ZrO2、
TiO2またはこれらの酸化物の一部ないし全部を
混合したものが含まれる。
か焼体の含有量としては、あまりに少量である
と廃棄物の処理能率が低下するが、一方か焼体の
量が多すぎるとセラミツク固化体の形成が困難と
なるため全重量に対し、20〜40％の範囲が適当で
ある。本発明にしたがい、まず上記したようなか
焼体粉末とセラミツク形成物質粉末を混合した後
一定形状に圧縮、成形し、これを900〜1100℃の
温度で焼成して多孔質の焼結体を形成する。800
℃以下で焼成した場合、か焼体粉末とセラミツク
形成物質が反応して化学的に安定な化合物を形成
するに到らず未反応のまま焼成が終了することが
多く不適当である。一方1200℃以上で焼成した場
合は焼結体が多孔質となりにくく溶融金属を含浸
させることが困難となる。
また焼成時の圧力に関しては、一般に常圧下で
焼成することで足りる。焼結体強度を上げるため
加圧することもできるが、焼結体に気孔性を与え
る程度の圧力であることが好ましい。
次いで、得られた多孔質焼結体を容器に装入
し、該容器中で溶融金属を上記多孔質焼結体に含
浸させた後冷却固化する。溶融金属を多孔質焼結
体に含浸させる方法としては、(イ)多孔質焼結体を
装入した容器中に溶融金属を流し込む方法、(ロ)多
孔質焼結体と金属（粉末）を容器に装入した後、
加熱し容器内部の金属を溶融する方法などが用い
られる。
さらに、多孔質焼結体への溶融金属の含浸を促
進するために以下のような方法をとることが好ま
しい。
(a) 多孔質焼結体を装入した容器を10-2気圧以下
の真空度に保ちながら溶融金属の含浸を開始す
る方法。
(b) 溶融金属の多孔質焼結体への含浸ならびに固
化の過程で１〜100気圧の圧力で加圧する方法。
含浸用の金属材料としては、容器材料の耐熱温
度以下での溶融性の点から、Cu、Fe、Al、Pb、
Sn、Zn、Niおよびこれらの金属の少なくとも一
種を主成分とする合金などが適する。例えば、
Cu製の容器中で溶融金属を用いる場合は、Pb、
Sn、Zn、Alおよびこれらの金属の少なくとも一
種を主成分とする合金などが適する。
焼結体を装入する容器の材料としては、例えば
Fe、Al、Cu、Ni、Ti、Zrまたはこれらのうちの
少なくとも一種を主成分とする合金などが用いら
れる。例えば、多孔質焼結体を含浸する金属材料
としてCu−Zn合金（Cu50％、Zn50％）を用いる
場合、融点、機械的強度を考慮して、Fe、Cu、
Ni、Ti、Zrまたはこれらのうちの少なくとも一
種を主成分とする合金が好ましく用いられる。
容器の大きさは、その容積が大きい程、放射性
廃棄物の固化量を多くすることができるが、大き
すぎると、熱伝導性、機械的強度が低下するので
好ましくない。例えば、円筒状の容器とした場
合、内径は５〜50mmが望ましい。また容器の肉厚
は、厚い程腐食による減肉に対し耐久性があり、
また機械的強度の点でも有利であるが、厚すぎる
と熱伝導性が低下するので0.5〜５mmの範囲が望
ましい。
このようにして得られた、内部に金属で含浸さ
れた焼結体固化体を有する容器（内部容器）の１
または２以上を、さらに外部容器（貯蔵容器）中
に金属を用いて埋没することもできる。埋設方法
としては、(イ)内部容器を金属粉末とともに圧縮成
形し、必要に応じて更に焼結するか、あるいは外
部容器に装入して容器ごと加熱して内部の金属を
溶融後、冷却固化する方法、(ロ)内部容器を外部容
器内に装入後、溶融金属を注入した後冷却する方
法、(ハ)逆に外部容器内に適量の溶融金属を入れて
おき、しかる後に内部容器を装入してから溶融金
属を冷却固化させる方法、などが用いられる。た
だし、内部容器を２以上埋設する場合も、互いに
適宜離間させて、外部容器の中央近傍に置いて外
界からできるだけ遮断することが望ましいのは云
うまでもない。
外部容器の材料としては、たとえばFe、Al、
Cu、Pb、Sn、Zn、Ni、Ti、Zrまたは、これら
のうち少なくとも一種を主成分とする合金などが
用いられ、上記固化方法や埋設方法に応じて適宜
決定される。例えば、多孔質焼結体にCu−Zn合
金（Cu50％、Zn50％）を含浸させ固化させた内
部容器を、溶融Pbを用いて外部容器中で埋設す
る場合には、融点、機械的強度を考慮して、Fe、
Al、Cu、Ni、Ti、Zrまたはこれらのうち少なく
とも一種を主成分とする合金が好ましく用いられ
る。
なお上記固化工程および埋設工程後、それぞれ
内部容器および外部容器と同様な材料よりなるフ
タをかぶせ、周縁を溶接等により密封する。
上述したような本発明の方法により得られる放
射性廃棄物貯蔵体は、たとえば外部容器中に１個
の内部容器を埋設する場合について図面に示すよ
うな構造となる。すなわち、金属で含浸された多
孔質焼結体１が金属とともに内部容器２中で固化
されており、この内部容器２が外部容器３のほぼ
中央部において、更に金属４中に埋設されてい
る。このように金属により多重に被覆された結
果、本発明による放射性廃棄物貯蔵体は、機械
的、化学的安定性が極めて高く、長期にわたる安
全な貯蔵に好適なものとなる。すなわち、本発明
による貯蔵体の場合、万一貯蔵容器（外部容器）
３が破損した場合でも、放射性廃棄物とセラミツ
ク形成物質から形成される多孔質焼結体に金属を
含浸させたもの１は、更に埋設金属４および内部
容器２により外部雰囲気、例えば海水から遮断さ
れているため、外部雰囲気に直接接触するおそれ
は極めて少ない。金属の水への極めて小さい浸出
率を考慮すると、上記のごとき貯蔵容器破損の事
故があつてもなお長期の安全貯蔵は確保される。
また、万が一埋設金属４を通じての浸水ならびに
内部容器の破損があつても、か焼した放射性廃棄
物とセラミツク形成物質から形成される多孔質焼
結体に金属を含浸させたもの１は内部容器２に囲
まれているため外部とは隔離されている。また、
更に内部容器２が破損しても、内容物である多孔
質焼結体は金属によつて含浸されているため、機
械的に強く、多孔質焼結体から成る固化体に較べ
てはるかにすぐれている。
〔発明の実施例および比較例〕
実施例
下表に示す組成の模擬放射性廃棄物のか焼体粉
末（再処理工場より出る廃液をか焼して得られる
酸化物を模擬したもの）を用意した。
[Technical Field of the Invention] The present invention relates to a method for disposing of radioactive waste, and more specifically to a porous sintered material formed by heating and firing a mixed powder of a radioactive waste calcined body and a ceramic forming material after molding. The present invention relates to a method of manufacturing a radioactive waste storage body that is chemically and mechanically stable and suitable for semi-permanent storage by impregnating a body with molten metal. [Technical Background of the Invention] With the spread of nuclear power generation, highly concentrated radioactive waste fluids generated from spent nuclear fuel reprocessing plants are increasing year by year, and it is becoming increasingly difficult to store these radioactive waste fluids in liquid form in tanks. In particular, there are safety issues, so there is a strong desire to establish a technology to convert it into a solid storage medium that can be stored more safely. Generally, when disposing of radioactive waste, the waste is solidified in a form that minimizes the diffusion of radioactive materials into the surrounding area, and the resulting solid storage medium is chemically and mechanically stable and has a long-term lifespan. It is necessary that storage does not cause environmental pollution. From this point of view, the ceramic solidification method (for example, Japanese Patent Application Laid-Open No. 1983-1999) is a solidification method that has been proposed to date.
No. 12447, No. 55-12448, No. 55-87100, No. 55
-90463, etc.). This method involves adding an appropriate amount of a ceramic-forming substance such as alumina, silica, or titania to a calcined body of radioactive waste, compression molding it, and then heating and firing it to produce a solidified ceramic body of a certain shape. . [Problems in the background art] According to the conventional ceramic solidification method as described above, by firing at a high temperature of usually 1200°C or higher, it is possible to produce a sintered body that has relatively high mechanical strength, is dense, and has excellent water resistance. However, it has the following problems. (a) In general, the lower the firing temperature is, the easier it is to produce a solidified product, and it is also advantageous in terms of reducing the burden on firing equipment such as a furnace. Therefore, it is desirable to be able to form a sintered body at a relatively low temperature of 1200°C or lower. However, according to the research of the present inventors, within the composition range of ceramic-forming substances that have been published so far, if firing is performed at a temperature below 1200°C, only a mechanically weak and porous sintered body can be obtained. Nakatsuta. (b) Solidified ceramics are susceptible to mechanical shock, and assuming that the storage container for the solidified material is damaged,
Since the solidified material comes into direct contact with the external atmosphere, for example, groundwater in the case of underground storage,
It is required to reduce the leaching rate of radioactive substances into the external atmosphere such as water as much as possible. (c) Since the solidified ceramic body has essentially low thermal conductivity, the heat generated due to the radioactive decay of the radioactive material contained in the solidified body cannot be sufficiently dissipated. This causes problems such as internal deterioration due to temperature rise inside the solidified body and the escape of highly luminescent substances to the outside, making it difficult to safely store radioactive waste over a long period of time. [Object of the Invention] The present invention eliminates the drawbacks of the conventional ceramic solidification method as described above, and provides a ceramic material that has excellent mechanical strength, chemical stability, and heat dissipation properties, and can be safely stored for a long period of time. The purpose is to provide a method for manufacturing a radioactive waste storage body. [Summary of the Invention] According to the research conducted by the present inventors, a porous sintered body obtained by firing a mixture of a calcined body of radioactive waste and a ceramic-forming substance at a relatively low temperature of 1200°C or lower. It has been found that by impregnating molten metal with solidified material and solidifying it, a radioactive waste storage body with superior mechanical strength and heat dissipation properties compared to conventional solidified ceramics can be obtained. That is, the radioactive waste treatment method of the present invention involves mixing 20 to 40% by weight of calcined radioactive waste and 80 to 60% by weight of a ceramic forming substance, shaping the mixture, and then heating and firing it at a temperature of 900 to 1100°C. It is characterized by comprising a step of forming a porous sintered body, and a step of charging the porous sintered body into a container, impregnating the porous sintered body with molten metal and solidifying it in the container. It is something. [Specific Description of the Invention] The present invention will be described in more detail below. In the following description, "parts" and "%" are based on weight unless otherwise specified. Radioactive waste to be treated by the present invention includes, for example, U, Pu, etc. after processing spent nuclear fuel.
In addition to the remaining radioactive waste collected, various waste liquids containing radioactive materials, such as concentrated recycled waste liquid from mixed bed desalination equipment, concentrated waste liquid from floor drains or equipment drains generated from buildings, and even atomic water. High-level and Contains medium to low level radioactive waste. By calcining these radioactive wastes, a calcined body can be obtained as a raw material. On the other hand, ceramic forming substances include Al 2 O 3 , SiO 2 , BaO, SrO, ZrO 2 ,
It includes TiO 2 or a mixture of some or all of these oxides. If the content of the calcined body is too small, the waste treatment efficiency will decrease, but on the other hand, if the amount of the calcined body is too large, it will be difficult to form a solidified ceramic body. A range of ~40% is appropriate. According to the present invention, first, the above-mentioned calcined body powder and ceramic forming material powder are mixed, then compressed and molded into a certain shape, and then fired at a temperature of 900 to 1100°C to form a porous sintered body. do. 800
If the firing is performed at a temperature below .degree. C., the calcined body powder and the ceramic-forming substance will not react to form a chemically stable compound, and the firing will often end without any reaction, which is inappropriate. On the other hand, if the sintered body is fired at 1200°C or higher, it becomes difficult to make the sintered body porous and impregnated with molten metal. Regarding the pressure during firing, it is generally sufficient to perform firing under normal pressure. Although pressure can be applied to increase the strength of the sintered body, it is preferable that the pressure be applied to a level that imparts porosity to the sintered body. Next, the obtained porous sintered body is charged into a container, and the porous sintered body is impregnated with molten metal in the container, and then cooled and solidified. Methods for impregnating a porous sintered body with molten metal include (a) a method of pouring the molten metal into a container charged with the porous sintered body, and (b) a method of impregnating the porous sintered body and metal (powder). After charging into the container,
A method of heating and melting the metal inside the container is used. Furthermore, in order to promote impregnation of the molten metal into the porous sintered body, it is preferable to take the following method. (a) A method in which impregnation with molten metal is started while maintaining a vacuum level of 10 -2 atmospheres or less in a container containing a porous sintered body. (b) A method in which molten metal is impregnated into a porous sintered body and pressurized at a pressure of 1 to 100 atmospheres during the solidification process. Metal materials for impregnation include Cu, Fe, Al, Pb, and
Suitable materials include Sn, Zn, Ni, and alloys containing at least one of these metals as a main component. for example,
When using molten metal in a Cu container, Pb,
Suitable materials include Sn, Zn, Al, and alloys containing at least one of these metals as a main component. Examples of materials for the container into which the sintered body is charged include:
Fe, Al, Cu, Ni, Ti, Zr, or an alloy containing at least one of these as a main component is used. For example, when using a Cu-Zn alloy (50% Cu, 50% Zn) as the metal material to impregnate a porous sintered body, considering the melting point and mechanical strength, Fe, Cu,
Ni, Ti, Zr, or an alloy containing at least one of these as a main component is preferably used. As for the size of the container, the larger the volume, the more radioactive waste can be solidified, but if the container is too large, the thermal conductivity and mechanical strength will decrease, which is not preferable. For example, in the case of a cylindrical container, the inner diameter is preferably 5 to 50 mm. In addition, the thicker the wall of the container, the more durable it will be against thinning due to corrosion.
It is also advantageous in terms of mechanical strength, but if it is too thick, thermal conductivity decreases, so a range of 0.5 to 5 mm is desirable. 1 of the thus obtained container (inner container) having a solidified sintered body impregnated with metal
Alternatively, two or more can be further embedded in an external container (storage container) using metal. As for the burial method, (a) the inner container is compression molded with metal powder and further sintered if necessary, or it is inserted into the outer container and heated together to melt the metal inside, and then cooled and solidified. (b) A method in which the inner container is charged into the outer container, molten metal is poured into the outer container, and then cooled. (c) Conversely, an appropriate amount of molten metal is placed in the outer container, and then the inner container is removed. A method is used in which the molten metal is cooled and solidified after being charged. However, even when two or more inner containers are buried, it goes without saying that it is desirable to space them appropriately apart from each other and place them near the center of the outer container to isolate them from the outside world as much as possible. Examples of materials for the outer container include Fe, Al,
Cu, Pb, Sn, Zn, Ni, Ti, Zr, or an alloy containing at least one of these as a main component is used, and is appropriately determined depending on the solidification method and embedding method. For example, when a porous sintered body is impregnated with Cu-Zn alloy (50% Cu, 50% Zn) and solidified, an inner container is buried in an outer container using molten Pb, the melting point and mechanical strength are Considering,Fe,
Al, Cu, Ni, Ti, Zr, or an alloy containing at least one of these as a main component is preferably used. After the solidification step and the burying step, a lid made of the same material as the inner container and the outer container is respectively placed on the container, and the periphery is sealed by welding or the like. The radioactive waste storage body obtained by the method of the present invention as described above has a structure as shown in the drawings, for example, when one inner container is buried in an outer container. That is, a porous sintered body 1 impregnated with metal is solidified together with the metal in an inner container 2, and this inner container 2 is further embedded in the metal 4 at approximately the center of the outer container 3. As a result of being coated multiple times with metal in this way, the radioactive waste storage body according to the present invention has extremely high mechanical and chemical stability, and is suitable for long-term safe storage. That is, in the case of the storage body according to the invention, if the storage container (external container)
Even if part 3 is damaged, part 1, which is a porous sintered body formed from radioactive waste and ceramic-forming material and impregnated with metal, is further isolated from the external atmosphere, such as seawater, by buried metal 4 and internal container 2. Therefore, the risk of direct contact with the external atmosphere is extremely low. Considering the extremely low leaching rate of metals into water, long-term safe storage is ensured even in the event of the above-mentioned storage container breakage.
In addition, even if water intrudes through the buried metal 4 and the internal container is damaged, the inner container 1, which is made of a porous sintered body formed from calcined radioactive waste and ceramic-forming material and impregnated with metal, It is isolated from the outside world because it is surrounded by Also,
Furthermore, even if the inner container 2 is damaged, the porous sintered body contained therein is impregnated with metal, so it is mechanically strong and far superior to a solidified body made of porous sintered body. ing. [Examples and Comparative Examples of the Invention] Example Calcined powder of simulated radioactive waste (simulating the oxide obtained by calcining waste liquid from a reprocessing plant) having the composition shown in the table below was prepared.
上述した実施例、比較例から明らかなように、
本発明の貯蔵体は、1200℃以下の比較的低温の焼
成によつて得られる多孔質焼結体の周辺および気
孔内部が金属により含浸、固化されているため、
熱の放散性にすぐれるとともに、機械的、化学的
に安定である。
さらにまた、本発明の貯蔵体は、最外側の貯蔵
容器が破損して内部固形体が露出した場合であつ
ても、その内部に固化された放射性元素が浸出す
ることがなく、単なるセラミツク固化体よりも安
全性、長期貯蔵性にすぐれている。
As is clear from the above-mentioned Examples and Comparative Examples,
In the storage body of the present invention, the periphery and inside of the pores of the porous sintered body obtained by firing at a relatively low temperature of 1200°C or less are impregnated and solidified with metal.
It has excellent heat dissipation properties and is mechanically and chemically stable. Furthermore, even if the outermost storage container is damaged and the internal solid body is exposed, the storage body of the present invention prevents the solidified radioactive element from leaching out, and is a mere solidified ceramic body. It is safer and has better long-term storage.
図面は、本発明の方法の一態様により得られる
貯蔵体の縦断面図である。
１……か焼した放射性廃棄物とセラミツク形成
物質から得られる多孔質焼結体に金属を含浸、固
化させたもの、２……内部容器、３……外部容
器、４……埋設用金属。
The drawing is a longitudinal section through a storage body obtained by one embodiment of the method of the invention. 1... Porous sintered body obtained from calcined radioactive waste and ceramic forming material impregnated with metal and solidified, 2... Inner container, 3... Outer container, 4... Metal for burial.
Claims (1)
ツク形成物質80〜60重量％とを混合し成形した後
900〜1100℃の温度で加熱焼成し多孔質焼結体を
形成する工程と、該多孔質焼結体を容器に装入
し、該容器中で溶融金属を前記多孔質焼結体に真
空または加圧下で、気孔内部まで含浸させ固化さ
せる工程からなることを特徴とする放射性廃棄物
の処理方法。 ２ 多孔質焼結体を装入した容器を10-2気圧以下
の真空に保ちながら溶融金属の含浸を開始する、
特許請求の範囲第１項記載の放射性廃棄物の処理
方法。 ３ 溶融金属の多孔質焼結体への含浸ならびに固
化を、１〜100気圧の加圧下で行なう、特許請求
の範囲第１項または第２項記載の放射性廃棄物の
処理方法。[Claims] 1. After mixing and molding 20 to 40% by weight of calcined radioactive waste and 80 to 60% by weight of a ceramic forming substance.
A step of heating and firing at a temperature of 900 to 1100°C to form a porous sintered body, charging the porous sintered body into a container, and applying molten metal to the porous sintered body in the container under vacuum or A method for disposing of radioactive waste, comprising a step of impregnating and solidifying the inside of the pores under pressure. 2. Start impregnation with molten metal while keeping the container containing the porous sintered body in a vacuum of 10 -2 atmospheres or less,
A method for treating radioactive waste according to claim 1. 3. The method for treating radioactive waste according to claim 1 or 2, wherein the porous sintered body is impregnated with molten metal and solidified under a pressure of 1 to 100 atmospheres.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2856382A JPS58146898A (en) | 1982-02-24 | 1982-02-24 | Method of processing radioactive waste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2856382A JPS58146898A (en) | 1982-02-24 | 1982-02-24 | Method of processing radioactive waste |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58146898A JPS58146898A (en) | 1983-09-01 |
| JPH0119560B2 true JPH0119560B2 (en) | 1989-04-12 |
Family
ID=12252102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2856382A Granted JPS58146898A (en) | 1982-02-24 | 1982-02-24 | Method of processing radioactive waste |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58146898A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6350800A (en) * | 1986-08-21 | 1988-03-03 | 新日本無線株式会社 | Method of processing waste containing radioactive substance |
| US7365237B2 (en) * | 2002-09-26 | 2008-04-29 | Clean Technologies International Corporation | Liquid metal reactor and method for treating materials in a liquid metal reactor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5512448A (en) * | 1978-07-14 | 1980-01-29 | Tokyo Shibaura Electric Co | Ceramiccsolidified radioactive waste* and manufacture thereof |
| JPS5512447A (en) * | 1978-07-14 | 1980-01-29 | Tokyo Shibaura Electric Co | Ceramiccsolidified radioactive waste* and manufacture thereof |
| JPS5610296A (en) * | 1979-07-06 | 1981-02-02 | Tokyo Shibaura Electric Co | Radioactive waste processing method |
-
1982
- 1982-02-24 JP JP2856382A patent/JPS58146898A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5512448A (en) * | 1978-07-14 | 1980-01-29 | Tokyo Shibaura Electric Co | Ceramiccsolidified radioactive waste* and manufacture thereof |
| JPS5512447A (en) * | 1978-07-14 | 1980-01-29 | Tokyo Shibaura Electric Co | Ceramiccsolidified radioactive waste* and manufacture thereof |
| JPS5610296A (en) * | 1979-07-06 | 1981-02-02 | Tokyo Shibaura Electric Co | Radioactive waste processing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58146898A (en) | 1983-09-01 |
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