JP2013068574A - Method and mixture for coping with soil contaminated by radioactive substances - Google Patents
Method and mixture for coping with soil contaminated by radioactive substances Download PDFInfo
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- JP2013068574A JP2013068574A JP2011208998A JP2011208998A JP2013068574A JP 2013068574 A JP2013068574 A JP 2013068574A JP 2011208998 A JP2011208998 A JP 2011208998A JP 2011208998 A JP2011208998 A JP 2011208998A JP 2013068574 A JP2013068574 A JP 2013068574A
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Abstract
Description
本発明は、セシウム等の放射能物質により汚染された土壌の表面線量を低下させる土壌の処理方法に関する。
ここに「放射能物質」とは放射線（γ線、α線、β線、中性子線など）を出す物質全般をいい、「表面線量」とは放射能物質を含む土壌又はその容器等の外側表面における放射線の線量率（Ｓｖ／ｈ）をいう。
The present invention relates to a soil treatment method for reducing the surface dose of soil contaminated with radioactive substances such as cesium.
Here, “radioactive substance” means all substances that emit radiation (γ-rays, α-rays, β-rays, neutrons, etc.), and “surface dose” means the outer surface of the soil or its container containing radioactive substances. The radiation dose rate (Sv / h) in
原子炉の事故や大気圏核実験により環境中に放出された放射能物質であるセシウム（Ｃｓ）は、イオン態として雨に溶けた状態で土壌に降下する割合が大きいと考えられる。
Ｃｓは、土壌に降下すると、カリウム同様、１価の陽イオンとして振る舞う。土壌は、負の電荷を帯びているために、１価の陽イオンを持つＣｓは、土壌の表面に止まる。土壌に含まれる粘土鉱物の種類によっては、負電荷のある場所が、Ｃｓを閉じ込めるのに好適の大きさを持つものがある。そのため、Ｃｓは他の陽イオンに比べて土壌から離れにくい傾向にある。
Cesium (Cs), which is a radioactive substance released into the environment by nuclear reactor accidents and atmospheric nuclear tests, is considered to have a high rate of falling to the soil in an ionic state dissolved in rain.
When Cs falls to the soil, it behaves as a monovalent cation like potassium. Since soil is negatively charged, Cs having a monovalent cation stays on the surface of the soil. Depending on the types of clay minerals contained in the soil, there are those where a place with a negative charge has a size suitable for confining Cs. Therefore, Cs tends to be less likely to leave the soil than other cations.
大気圏核実験に由来するＣｓ−１３７は、主に１９６０年代に地球全体に拡散して土壌に降下した。日本における水田及び畑土壌のＣｓ−１３７濃度は、降下量の多かった１９６３〜１９６６年をピークに減少しており、作土内における滞留半減時間は水田作土で９〜２４年、畑作土で８〜２６年と報告されている。
なお、Ｃｓ−１３７濃度の減少には、下層への溶脱の他に、放射壊変による減衰も含んでいる。土壌中のＣｓ−１３７の分布を粘土、シルト、砂に分けて調べた例では、半分以上のＣｓ−１３７が粘土画分に存在しており、また、土壌への吸着の強さや様式で分けると、カリウムやアンモニウムイオン等の陽イオンと置き換わることができるイオン交換態が１０％、有機物との結合体が２０％、粘土鉱物等との強固な結合体が７０％と報告されている。
Cs-137 derived from the atmospheric nuclear test was diffused throughout the earth mainly in the 1960s and dropped to the soil. The Cs-137 concentration in paddy fields and field soils in Japan decreased after peaking from 1963 to 1966, and the half-life in the soils was 9-24 years for paddy field soils. It is reported as 8 to 26 years.
The decrease in the Cs-137 concentration includes attenuation due to radiation decay in addition to leaching to the lower layer. In an example in which the distribution of Cs-137 in the soil was examined by dividing it into clay, silt, and sand, more than half of the Cs-137 was present in the clay fraction, and was divided according to the strength and mode of adsorption to the soil. It is reported that the ion exchange state capable of replacing cations such as potassium and ammonium ions is 10%, the conjugate with the organic matter is 20%, and the strong conjugate with the clay mineral is 70%.
１０年単位で土壌に残留するＣｓは、人体に対して影響を及ぼすことも考えられる。そのために、Ｃｓによる汚染が広がることを防止する必要がある。そこで、Ｃｓを水に不溶化する技術についての要求が高まっている。 Cs remaining in the soil every 10 years may have an effect on the human body. Therefore, it is necessary to prevent the contamination by Cs from spreading. Thus, there is an increasing demand for a technique for insolubilizing Cs in water.
特許文献１には、重金属等で汚染された産業廃棄物、土壌等の有害物質を固化処理して、重金属等を固化物に封じ込め、それらの溶出を抑える発明が記載されている。この発明では、水硬性材料に固化助剤及び硫酸第一鉄等の還元性物質を併用し、有害物質に還元性物質を混練した後、水硬性材料と固化助剤を混練することで、重金属等を固化物に封じ込める。 Patent Document 1 describes an invention in which hazardous substances such as industrial waste and soil contaminated with heavy metals are solidified to contain heavy metals and the like in a solidified product and suppress their elution. In this invention, a solidification aid and a reducing substance such as ferrous sulfate are used in combination with the hydraulic material, and after kneading the reducing substance into the harmful substance, the hydraulic material and the solidification aid are kneaded, Etc. are contained in a solidified product.
特許文献１の技術では、重金属の封じ込めに対しては、ある程度の効果を期待できる。しかし、Ｃｓ−１３７のような放射能物質に対しては、単なる封じ込めの他に、放射線の表面線量を低減させなければ安定化した処理とはいえない。この点、特許文献１では、放射線の表面線量については考慮されておらず、期待できない。 In the technique of Patent Document 1, a certain degree of effect can be expected for containment of heavy metals. However, a radioactive substance such as Cs-137 cannot be said to be a stabilized process unless the surface dose of radiation is reduced, in addition to simple containment. In this regard, in Patent Document 1, the surface dose of radiation is not considered and cannot be expected.
本発明は、このような問題を解決するために、Ｃｓ等の放射能物質により汚染された汚泥を安定化して処理する技術を提供することを課題とする。 In order to solve such problems, an object of the present invention is to provide a technique for stabilizing and treating sludge contaminated with a radioactive substance such as Cs.
以上の課題を解決する本発明の土壌の処理方法は、放射能物質により汚染された土壌に、前記放射能物質の溶け出しを抑止する不溶化剤、セメント、及び液体をそれぞれ所定割合で混合することにより、前記土壌における表面線量を低下させることを特徴とする。
好適には、前記土壌が７１重量％、前記不溶化剤が４重量％、前記セメントが１４重量％、前記液体が１１重量％になるように混合する。
In the soil treatment method of the present invention that solves the above-mentioned problems, an insolubilizer, cement, and liquid that inhibit dissolution of the radioactive substance are mixed with the soil contaminated with the radioactive substance at a predetermined ratio. To reduce the surface dose in the soil.
Preferably, mixing is performed so that the soil is 71% by weight, the insolubilizing agent is 4% by weight, the cement is 14% by weight, and the liquid is 11% by weight.
本発明は、また、放射能物質により汚染された土壌における前記放射能物質を安定化させる混合物を提供する。この混合物は、前記放射能物質の溶出を抑止するための不溶化剤と、セメントと、液体とをそれぞれ所定割合で含む。 The present invention also provides a mixture that stabilizes said radioactive material in soil contaminated with radioactive material. This mixture contains an insolubilizing agent for suppressing elution of the radioactive substance, cement, and liquid at a predetermined ratio.
このように放射能物質により汚染された土壌を上記混合物を用いて処理することで、現在、災害や事故により仮置きされている放射能物質により汚染された土壌を、放射線の表面線量を低減させながら固化することができる。固化により土壌の飛散防止につながり、ハンドリング性が向上する。さらに、この混合物を埋設した場合でも、土壌が溶出することなく、埋設地の地質汚染の可能性も低くなる。 By treating the soil contaminated with radioactive substances in this way with the above mixture, the soil contaminated with radioactive substances temporarily placed due to disasters and accidents can be reduced. It can be solidified. Solidification leads to prevention of soil scattering and improves handling. Furthermore, even when this mixture is buried, the soil does not elute and the possibility of geological contamination of the buried land is reduced.
以上のように、本発明によれば、不溶化剤、セメント、及び液体を放射能物質により汚染された土壌に混合することで、放射線の表面線量を低減させ、安定化して処理することができるという特有の効果を奏することができる。 As described above, according to the present invention, the surface dose of radiation can be reduced and stabilized by mixing insolubilizer, cement, and liquid with soil contaminated with radioactive materials. A specific effect can be produced.
本発明の実施形態では、放射能物質で汚染された土壌に、不溶化剤、セメント、及び水を混合した混合物を拡散させた。 In the embodiment of the present invention, a mixture of an insolubilizing agent, cement, and water is diffused in soil contaminated with radioactive materials.
不溶化剤には、重金属等の汚染物質をセメント固化時に封じ込め、拡散、溶出を防止できるものがよい。また、セメント固化時にセメントの使用量を削減でき、粒状からブロックまで、様々な形に成形可能で、セメントの強度を向上させるものが好ましい。このような理由から、本実施形態では、不溶化剤として株式会社ゲオドール・ジャパン製のゲオドール（登録商標）を用いるが、同様の性質も持てばこれに限るものでは無い。 The insolubilizing agent is preferably one that can contain contaminants such as heavy metals during cement solidification and prevent diffusion and elution. Moreover, what can reduce the usage-amount of cement at the time of cement solidification, can be shape | molded in various shapes from a granular form to a block, and the thing which improves the intensity | strength of cement is preferable. For this reason, in this embodiment, Geodol (registered trademark) manufactured by Geodol Japan Co., Ltd. is used as an insolubilizing agent, but the present invention is not limited to this as long as it has similar properties.
汚染土壌を試料Ａ、汚染土壌にセメント、及び水を混合した混合物を試料Ｂ、汚染土壌に、ゲオドール、セメント、及び水を混合した混合物を試料Ｃとして、それぞれの放射線の表面線量を測定した。試料Ａ、Ｂ、Ｃにおける各構成物の構成比率及び表面線量の測定結果を図１に示す。なお、測定時のバックグラウンドの線量は０．１０［μＳｖ／ｈ］であった。 The surface dose of each radiation was measured using Sample A as the contaminated soil, Sample B as the mixture obtained by mixing cement and water in the contaminated soil, and Sample C as the mixture obtained by mixing geodol, cement and water in the contaminated soil. FIG. 1 shows the measurement results of the constituent ratio and the surface dose of each constituent in Samples A, B, and C. The background dose at the time of measurement was 0.10 [μSv / h].
図１からわかるように、汚染土壌自体からは、０．２５［μＳｖ／ｈ］の放射線が放射されている。これに対して、不溶化剤（ゲオドール）を混合することで、試料Ｃにおいては、表面線量がバックグラウンドの線量と同値である０．１０［μＳｖ／ｈ］である。つまり、試料Ｃからは殆ど放射線が放射されなくなった。 As can be seen from FIG. 1, radiation of 0.25 [μSv / h] is emitted from the contaminated soil itself. On the other hand, by mixing an insolubilizing agent (geodol), in the sample C, the surface dose is 0.10 [μSv / h] which is the same value as the background dose. That is, almost no radiation was emitted from the sample C.
このように、不溶化剤（ゲオドール）を混合することで、放射線の表面線量を低減しつつ、汚染土壌を固化することで不溶化し、汚染土壌に含まれる放射能物質を安定化させることができる。 As described above, by mixing the insolubilizing agent (geodol), it is possible to stabilize the radioactive substance contained in the contaminated soil by reducing the surface dose of radiation and solidifying the contaminated soil.
Claims (3)
請求項１記載の土壌の処理方法。 Mixing so that the soil is 71 wt%, the insolubilizer is 4 wt%, the cement is 14 wt%, and the liquid is 11 wt%,
The soil treatment method according to claim 1.
前記放射能物質の溶出を抑止するための不溶化剤と、セメントと、液体とをそれぞれ所定割合で含む、混合物。 A mixture that stabilizes said radioactive material in soil contaminated with radioactive material,
A mixture comprising an insolubilizing agent for inhibiting elution of the radioactive substance, cement, and liquid at a predetermined ratio.
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| JP2011208998A JP2013068574A (en) | 2011-09-26 | 2011-09-26 | Method and mixture for coping with soil contaminated by radioactive substances |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2015094608A (en) * | 2013-11-09 | 2015-05-18 | 恵和興業株式会社 | Method of manufacturing granulation/regeneration crushed stone by reducing radioactivity from radioactive waste |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2015094608A (en) * | 2013-11-09 | 2015-05-18 | 恵和興業株式会社 | Method of manufacturing granulation/regeneration crushed stone by reducing radioactivity from radioactive waste |
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