JPH08240695A - Treatment method of radioactive waste liquid - Google Patents
Treatment method of radioactive waste liquidInfo
- Publication number
- JPH08240695A JPH08240695A JP4303995A JP4303995A JPH08240695A JP H08240695 A JPH08240695 A JP H08240695A JP 4303995 A JP4303995 A JP 4303995A JP 4303995 A JP4303995 A JP 4303995A JP H08240695 A JPH08240695 A JP H08240695A
- Authority
- JP
- Japan
- Prior art keywords
- waste liquid
- radioactive
- acid
- waste
- decontamination
- 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.)
- Pending
Links
Landscapes
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、原子力発電所等から発
生する放射性廃液の処理方法に関するものであり、特に
放射性金属廃棄物を化学除染した除染廃液等の放射性廃
液の処理方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating radioactive waste liquid generated from a nuclear power plant or the like, and more particularly to a method for treating radioactive waste liquid such as decontamination waste liquid obtained by chemically decontaminating radioactive metal waste. Is.
【０００２】[0002]
【従来の技術】原子力発電所等から発生する放射性金属
廃棄物は、その表面のみに汚染物質が付着している場合
がほとんどであるため、硝酸、塩酸、フッ酸の混合酸等
を利用して金属表面層を溶解させ、汚染物質を除去する
方法が検討されている。この化学除染方法は除染性能が
高く、短時間での処理が可能と考えられている。2. Description of the Related Art In most cases, radioactive metal waste generated from nuclear power plants, etc. has contaminants attached only to its surface. Therefore, mixed acid of nitric acid, hydrochloric acid and hydrofluoric acid is used. Methods for dissolving the metal surface layer and removing contaminants have been investigated. It is considered that this chemical decontamination method has high decontamination performance and can be treated in a short time.
【０００３】ところがこの化学除染方法を実施すると、
二次廃棄物である金属イオンを含有する除染廃液が大量
に発生することとなる。また従来はこの二次廃液を完全
に処理する技術が確立していなかったため、除染廃液の
中和処理等に多量の薬剤が必要となる等の問題もあっ
た。However, when this chemical decontamination method is carried out,
A large amount of decontamination waste liquid containing metal ions, which is the secondary waste, is generated. Further, conventionally, a technique for completely treating the secondary waste liquid has not been established, so that there is a problem that a large amount of chemicals is required for neutralizing the decontamination waste liquid.
【０００４】[0004]
【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、放射性金属廃棄物の除染廃液等の放
射性廃液を、二次廃液をほとんど生じさせることなく処
理することができる放射性廃液の処理方法を提供するた
めに完成されたものである。The present invention solves the above-mentioned conventional problems and can treat radioactive waste liquid such as decontamination waste liquid of radioactive metal waste with almost no generation of secondary waste liquid. It has been completed to provide a method for treating radioactive liquid waste.
【０００５】[0005]
【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の放射性廃液の処理方法は、鉱酸を
含む放射性廃液を中和して放射性物質を沈殿させ、大部
分の放射性物質を含む沈殿物を分離した後の廃液をバイ
ポーラ膜を用いた電気透析装置により鉱酸とアルカリと
脱塩水とに分離して回収することを特徴とするものであ
る。The method for treating radioactive waste liquid of the present invention, which has been made to solve the above problems, neutralizes radioactive waste liquid containing a mineral acid to precipitate radioactive substances, so that most radioactive substances are radioactive. It is characterized in that the waste liquid after separating the precipitate containing the substance is separated and recovered into mineral acid, alkali and demineralized water by an electrodialysis device using a bipolar membrane.
【０００６】[0006]
【作用】本発明によれば、バイポーラ膜を用いた電気透
析装置を用いることにより、除染廃液等の放射性廃液を
中和して金属イオンを沈殿分離した後の廃液から鉱酸と
アルカリと脱塩水とを分離回収することができる。そし
て回収された鉱酸は例えば除染液の原料として再利用で
き、回収されたアルカリは除染廃液の中和剤として再利
用でき、脱塩水も電気透析装置運転時の初期導入水、お
よび除染後の金属の洗浄水や中和残渣の洗浄水として再
利用することができるから、二次廃液の発生をほぼゼロ
とすることができる。According to the present invention, by using an electrodialyzer using a bipolar membrane, a radioactive waste liquid such as a decontamination waste liquid is neutralized and metal ions are precipitated and separated from the waste liquid to remove mineral acids, alkalis, and the like. It can be separated and recovered from salt water. Then, the recovered mineral acid can be reused, for example, as a raw material for the decontamination solution, the recovered alkali can be reused as a neutralizing agent for the decontamination waste solution, and the demineralized water can also be used as the initial introduction water during the operation of the electrodialysis device and the deionized water. Since it can be reused as the washing water for the metal after dyeing and the washing water for the neutralization residue, the generation of secondary waste liquid can be reduced to almost zero.
【０００７】[0007]
【実施例】以下に本発明を除染廃液の処理についての実
施例を参照しつつ、更に詳細に説明する。図１は本発明
の方法を説明するフローシートであり、従来と同様に放
射性金属廃棄物は除染室１の内部で鉱酸からなる除染液
で洗浄される。この鉱酸としては硝酸、塩酸、フッ酸の
混合酸を用いることが好ましく、実施例では硝酸：塩
酸：フッ酸の重量比が20：２：３のものが用いられてい
る。その結果、鉄やステンレスを主体とする放射性金属
廃棄物の表面は溶解され、金属表面に付着している放射
性物質は除染液中に移行する。EXAMPLES The present invention will be described in more detail below with reference to examples of treatment of decontamination waste liquid. FIG. 1 is a flow sheet for explaining the method of the present invention, in which radioactive metal waste is washed inside a decontamination chamber 1 with a decontamination solution consisting of a mineral acid as in the conventional case. As the mineral acid, it is preferable to use a mixed acid of nitric acid, hydrochloric acid and hydrofluoric acid, and a nitric acid: hydrochloric acid: hydrofluoric acid weight ratio of 20: 2: 3 is used in the examples. As a result, the surface of the radioactive metal waste mainly composed of iron or stainless steel is dissolved, and the radioactive substance adhering to the metal surface is transferred into the decontamination solution.
【０００８】このようにして生じた金属イオンを含有す
る除染廃液は、中和濾過槽２でアルカリにより中和され
る。実施例ではアルカリとしてＫＯＨが用いられ、除染
廃液中の金属イオンおよび大部分の放射性物質は水酸化
物として沈殿するので、濾過及び脱水処理により沈澱物
を分離する。この沈澱物は例えばカーボン坩堝に移し、
溶融助剤とともに1500℃で約２時間加熱すると、金属ブ
ロック状の固化体となり、減容される。The decontamination waste liquid containing metal ions thus produced is neutralized with alkali in the neutralization filtration tank 2. In the examples, KOH is used as the alkali, and the metal ions and most of the radioactive substances in the decontamination waste liquid precipitate as hydroxides, and thus the precipitates are separated by filtration and dehydration treatment. This precipitate is transferred to, for example, a carbon crucible,
When heated with a melting aid at 1500 ° C for about 2 hours, it becomes a metal block-like solidified body, and the volume is reduced.
【０００９】このようにして金属イオンを分離除去した
後の除染廃液は、バイポーラ膜を用いた電気透析装置３
に導かれる。バイポーラ膜とは片面にアニオン交換層、
もう一方の面にカチオン交換層を持つ特殊なイオン交換
膜であり、例えば株式会社トクヤマからネオセプタＢＰ
の商品名で市販されている。The decontamination waste liquid after separating and removing the metal ions in this way is an electrodialysis device 3 using a bipolar membrane.
Be led to. Anion exchange layer on one side with the bipolar membrane,
It is a special ion exchange membrane with a cation exchange layer on the other side, for example Neoceptor BP from Tokuyama Corporation.
It is marketed under the brand name of.
【００１０】図２は上記した電気透析装置３の原理を示
すフローシートであり、４が陽極、５がカチオン交換膜
（Ｃ膜）、６がバイポーラ膜（ＢＰ膜）、７がアニオン
交換膜（Ａ膜）、８が陰極、９がアルカリ室、10が酸
室、11が脱塩水室である。なお、試験では２dm2/枚のバ
イポーラ膜５枚、カチオン膜６枚、アニオン膜５枚を組
合せ装着した電気透析装置を用いた。このように電極と
膜とを配置し、陽極４と陰極８間に例えば電流密度10Ａ
/dm2の直流電流を通電しながら水を循環させると、バイ
ポーラ膜６には整流現象が生じ、水は連続してＨ+ とＯ
Ｈ- とに分解する。FIG. 2 is a flow sheet showing the principle of the electrodialysis device 3 described above. 4 is an anode, 5 is a cation exchange membrane (C membrane), 6 is a bipolar membrane (BP membrane), and 7 is an anion exchange membrane ( A film), 8 is a cathode, 9 is an alkaline chamber, 10 is an acid chamber, and 11 is a demineralized water chamber. In the test, an electrodialyzer equipped with 5 sheets of 2 dm 2 / sheet bipolar membrane, 6 sheets of cation membrane, and 5 sheets of anion membrane was used in combination. The electrodes and the membrane are arranged in this way, and a current density of 10 A, for example, is provided between the anode 4 and the cathode 8.
When water is circulated while applying a direct current of / dm 2, a rectification phenomenon occurs in the bipolar film 6 and the water continuously flows into H + and O 2.
Decomposes into H - and.
【００１１】そこでＫＯＨによる中和操作で生じたＫＮ
Ｏ3 、ＫＣｌ、ＫＦ等を含有する除染廃液を例えば流速
６cm/secで循環させると、Ｋ+ イオンはカチオン交換膜
５を通じてアルカリ室９に移動していき、ＮＯ3 - 、Ｃ
ｌ- 、Ｆ- イオンはアニオン交換膜７を通過して酸室１
０へ移動していく。そしてＮＯ3 - 、Ｃｌ - 、Ｆ- イオ
ンはバイポーラ膜６の整流現象により生じたＨ+ イオン
と結合し、ＨＮＯ3 、ＨＣｌ、ＨＦとなって元の混合酸
に戻る。またバイポーラ膜６の整流現象により生じたＯ
Ｈ- イオンはカチオン交換膜５を通じて供給されるＫ+
イオンと結合し、ＫＯＨに戻る。Therefore, KN produced by the neutralization operation with KOH
O3Flow rate of decontamination waste liquid containing KCl, KF, etc.
When circulating at 6 cm / sec, K+Ions are cation exchange membranes
Move to alkaline room 9 through 5, NO3 -, C
l-, F-Ions pass through the anion exchange membrane 7 and pass through the acid chamber 1
Move to 0. And NO3 -, Cl -, F-Io
H is generated by the rectification phenomenon of the bipolar film 6.+ion
Combined with HNO3, HCl, HF to become the original mixed acid
Return to O generated by the rectification phenomenon of the bipolar film 6
H-Ions are supplied through the cation exchange membrane K+
Combines with ions and returns to KOH.
【００１２】このようにして回収された混合酸は除染室
１へ返送され、除染液の原料として使用される。また、
回収されたアルカリは中和濾過槽２へ戻され、中和処理
に再使用される。更に脱塩水は電気透析装置３へ戻され
るとともに、その一部は除染後の金属の洗浄水や中和残
渣の洗浄水として再利用することができるから、二次廃
液の発生をほぼゼロとすることができる。The mixed acid thus recovered is returned to the decontamination chamber 1 and used as a raw material for the decontamination liquid. Also,
The recovered alkali is returned to the neutralization filtration tank 2 and reused for the neutralization treatment. Further, the demineralized water is returned to the electrodialysis device 3 and a part of it can be reused as the decontaminating metal washing water and the neutralization residue washing water, so that the generation of secondary waste liquid is almost zero. can do.
【００１３】電気透析装置３を用いた分離回収試験結果
の一例を次に示す。電気透析試験に当たって、循環液と
してアルカリ室９に水を５Ｌ、酸室10に水を1.5 Ｌ準備
した。また脱塩水室11には、硝酸：塩酸：フッ酸の重量
比が20：２：３の除染液でステンレス鋼を溶解し、３規
定のＫＯＨ溶液で中和後ろ過したろ液を９Ｌ準備し、運
転を開始した。図３は通電時間と酸回収率との関係を示
したグラフであり、除染廃液中からＨＮＯ3 、ＨＣｌ、
ＨＦの順で回収されることが分かる。また図４は通電時
間とアルカリ回収率との関係を示したグラフであり、除
染廃液中からＫＯＨが回収されることが分かる。さらに
４時間の通電を行えば、いずれの酸およびアルカリもほ
ぼ完全に回収でき、脱塩水の塩濃度も0.1 規定以下にす
ることが可能であることが分かった。An example of the results of the separation and recovery test using the electrodialysis device 3 is shown below. In the electrodialysis test, 5 L of water was prepared in the alkaline chamber 9 and 1.5 L of water was prepared in the acid chamber 10 as circulating fluids. In the demineralized water chamber 11, stainless steel was dissolved with a decontamination solution having a weight ratio of nitric acid: hydrochloric acid: hydrofluoric acid of 20: 2: 3, neutralized with 3N KOH solution, and filtered to prepare 9 L of a filtrate. And started driving. FIG. 3 is a graph showing the relationship between the energization time and the acid recovery rate. HNO 3 , HCl,
It can be seen that they are collected in the order of HF. FIG. 4 is a graph showing the relationship between the energization time and the alkali recovery rate, and it can be seen that KOH is recovered from the decontamination waste liquid. It has been found that, if electricity is further applied for 4 hours, any acid and alkali can be almost completely recovered, and the salt concentration of demineralized water can be set to 0.1 N or less.
【００１４】以上の説明は除染廃液の処理方法を中心と
してなされたが、本発明は鉱酸を含むその他の放射性廃
液の処理にも適用できることはいうまでもないことであ
る。Although the above description has been focused on the method for treating decontamination waste liquid, it goes without saying that the present invention can also be applied to the treatment of other radioactive waste liquids containing mineral acids.
【００１５】[0015]
【発明の効果】以上に説明したように、本発明の放射性
廃液の処理方法によれば、放射性物質を沈殿分離した後
の廃液をバイポーラ膜を用いた電気透析装置により鉱酸
とアルカリと脱塩水とに分離して回収することができる
から、二次廃液をほとんど生ずることがない。また本発
明を除染廃液の処理に適用すれば、金属沈澱物を金属ブ
ロック状の固化体とすることができるので、大幅な減容
化が可能となる。よって本発明は従来の問題点を解決し
た放射性廃液の処理方法として、工業的価値の高いもの
である。As described above, according to the method for treating radioactive waste liquid of the present invention, the waste liquid after the radioactive substance is precipitated and separated is treated with mineral acid, alkali, and demineralized water by an electrodialysis device using a bipolar membrane. Since it can be separated and collected into and, secondary waste liquid hardly occurs. Further, when the present invention is applied to the treatment of a decontamination waste liquid, the metal precipitate can be made into a metal block-shaped solidified body, so that the volume can be greatly reduced. Therefore, the present invention has a high industrial value as a method for treating radioactive waste liquid that solves the conventional problems.
【図１】本発明の方法を説明するフローシートである。FIG. 1 is a flow sheet illustrating the method of the present invention.
【図２】電気透析装置の原理を示すフローシートであ
る。FIG. 2 is a flow sheet showing the principle of an electrodialysis device.
【図３】通電時間と酸回収率との関係を示したグラフで
ある。FIG. 3 is a graph showing the relationship between energization time and acid recovery rate.
【図４】通電時間とアルカリ回収率との関係を示したグ
ラフである。FIG. 4 is a graph showing the relationship between energization time and alkali recovery rate.
１ 除染室、２ 中和濾過槽、３ 電気透析装置、４
陽極、５ カチオン交換膜（Ｃ膜）、６ バイポーラ膜
（ＢＰ膜）、７ アニオン交換膜（Ａ膜）、８陰極、９
アルカリ室、10 酸室、11 脱塩水室1 decontamination room, 2 neutralization filtration tank, 3 electrodialyzer, 4
Anode, 5 cation exchange membrane (C membrane), 6 bipolar membrane (BP membrane), 7 anion exchange membrane (A membrane), 8 cathode, 9
Alkaline chamber, 10 acid chamber, 11 demineralized water chamber
Claims (6)
物質を沈殿させ、沈殿物を分離した後の廃液をバイポー
ラ膜を用いた電気透析装置により鉱酸とアルカリと脱塩
水とに分離して回収することを特徴とする放射性廃液の
処理方法。1. A radioactive waste liquid containing a mineral acid is neutralized to precipitate a radioactive substance, and the waste liquid after separating the precipitate is separated into a mineral acid, an alkali and demineralized water by an electrodialysis device using a bipolar membrane. A method for treating a radioactive liquid waste, which is characterized in that
棄物の表面を鉱酸からなる除染液で溶解した金属イオン
を含有する除染廃液である請求項１に記載の放射性廃液
の処理方法。2. The treatment of a radioactive waste liquid according to claim 1, wherein the radioactive waste liquid containing a mineral acid is a decontamination waste liquid containing metal ions in which the surface of the radioactive metal waste is dissolved with a decontamination liquid consisting of a mineral acid. Method.
項１または２に記載の放射性廃液の処理方法。3. The method for treating a radioactive liquid waste according to claim 1, wherein the mineral acid is a mixed acid of nitric acid and hydrofluoric acid.
る請求項１または２に記載の放射性廃液の処理方法。4. The method for treating a radioactive liquid waste according to claim 1 or 2, wherein the mineral acid is a mixed acid of nitric acid, hydrochloric acid and hydrofluoric acid.
塩水中の塩濃度を0.1 規定以下にする請求項１〜３のい
ずれかに記載の放射性廃液の処理方法。5. The method for treating radioactive waste liquid according to claim 1, wherein the salt concentration in demineralized water is adjusted to 0.1 N or less by electrodialysis using a bipolar membrane.
ック状の固化体とする請求項２に記載の放射性廃液の処
理方法。6. The method for treating a radioactive waste liquid according to claim 2, wherein the precipitate of metal ions is melted to form a metal block-like solidified body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4303995A JPH08240695A (en) | 1995-03-02 | 1995-03-02 | Treatment method of radioactive waste liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4303995A JPH08240695A (en) | 1995-03-02 | 1995-03-02 | Treatment method of radioactive waste liquid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08240695A true JPH08240695A (en) | 1996-09-17 |
Family
ID=12652774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4303995A Pending JPH08240695A (en) | 1995-03-02 | 1995-03-02 | Treatment method of radioactive waste liquid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08240695A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2344340A (en) * | 1998-12-05 | 2000-06-07 | British Nuclear Fuels Plc | Treating acid contaminated with fission products |
| JP2014139530A (en) * | 2013-01-21 | 2014-07-31 | Toshiba Corp | Regeneration method of eluent and regenerating apparatus therefor |
-
1995
- 1995-03-02 JP JP4303995A patent/JPH08240695A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2344340A (en) * | 1998-12-05 | 2000-06-07 | British Nuclear Fuels Plc | Treating acid contaminated with fission products |
| JP2014139530A (en) * | 2013-01-21 | 2014-07-31 | Toshiba Corp | Regeneration method of eluent and regenerating apparatus therefor |
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