JPH0690309B2 - Decontamination method for radioactive metal waste - Google Patents
Decontamination method for radioactive metal wasteInfo
- Publication number
- JPH0690309B2 JPH0690309B2 JP15192486A JP15192486A JPH0690309B2 JP H0690309 B2 JPH0690309 B2 JP H0690309B2 JP 15192486 A JP15192486 A JP 15192486A JP 15192486 A JP15192486 A JP 15192486A JP H0690309 B2 JPH0690309 B2 JP H0690309B2
- Authority
- JP
- Japan
- Prior art keywords
- decontamination
- solution
- electrolytic
- radioactive
- radioactive metal
- 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
Landscapes
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Processing Of Solid Wastes (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、種々な形状の放射性金属廃棄物の除染方法に
係り、特に、放射性金属廃棄物を一般廃棄物並みの放射
能レベルにまで除染して放射性廃棄物量を減容する除染
方法に関する。TECHNICAL FIELD The present invention relates to a method for decontaminating radioactive metal wastes of various shapes, and in particular, decontaminating radioactive metal wastes to a level of radioactivity comparable to general wastes. And a decontamination method for reducing the volume of radioactive waste.
従来の技術 従来、この種の放射性金属廃棄物は、細かく切断される
などしてドラム缶詰めにし、放射性廃棄物貯蔵庫に貯蔵
されている。しかし、貯蔵中のドラム缶の数は、年々増
加の傾向にあり、また、将来予測される電子力発電所の
廃炉解体時には、放射性金属廃棄物だけで数万本のドラ
ム缶の発生が予想される。このことから、前記廃棄物の
減容化が望まれており、圧縮減容する方法や加熱溶融す
る方法が提案されている。しかし、このような方法にあ
っては、放射性物質で汚染されている表面部分と大部分
の非汚染部分とを一括処理してしまうため、その減容効
果は顕著とは言い難い。そこで、表面の汚染部分だけを
溶解除去して放射性金属廃棄物を減容する方法として、
電解研磨除染法が試みられている。2. Description of the Related Art Conventionally, radioactive metal wastes of this type are stored in radioactive waste storages after being diced into drum cans. However, the number of drums in storage tends to increase year by year, and tens of thousands of drums are expected to be generated only from radioactive metal waste when the decommissioning of an electronic power plant is expected to be dismantled in the future. . From this, it is desired to reduce the volume of the waste, and a method of compressing and reducing the volume and a method of heating and melting have been proposed. However, in such a method, since the surface portion contaminated with the radioactive material and most of the non-contaminated portion are collectively treated, the volume reduction effect cannot be said to be remarkable. Therefore, as a method to reduce the volume of radioactive metal waste by dissolving and removing only the contaminated part of the surface,
Electropolishing decontamination methods have been tried.
この方法には、電解液として、リン酸を主成分とする濃
厚な強酸性の電解液を使用する方法と、硫酸ナトリウ
ム、硝酸ナトリウム等の中性塩の溶液を使用する方法と
がある。前者の方法では、電解液中の放射能レベルが一
定値に達した時点で中和処理し、その後、固化するの
で、電解除染に伴う二次廃棄物が定期的に多量に発生す
るという欠点があった。これに対し、後者の方法では、
電解除染時に溶解した金属イオンが電解液中で金属水酸
化物になるので、この金属水酸化物を主成分とするスラ
ッジを分離すれば、電解液を再使用することができ、二
次廃棄物量を低減でき、放射性廃棄物の減容に大きな効
果を期待できる。This method includes a method of using a concentrated and strongly acidic electrolytic solution containing phosphoric acid as a main component and a method of using a solution of a neutral salt such as sodium sulfate or sodium nitrate as the electrolytic solution. In the former method, neutralization is performed when the radioactivity level in the electrolytic solution reaches a certain value, and then solidification is performed, so that a large amount of secondary waste is regularly generated due to electro-deletion dyeing. was there. On the other hand, in the latter method,
Dissolved metal ions during electrolysis dye become metal hydroxide in the electrolyte, so if the sludge containing this metal hydroxide as the main component is separated, the electrolyte can be reused and secondary disposal. The amount of material can be reduced and a great effect can be expected on the volume reduction of radioactive waste.
発明が解決しようとする問題点 しかし、電解研磨除染法は、電気化学的に表面の汚染部
分を溶解除去する方法であることから、汚染面と対向さ
せて電極を設置する必要があり、バルブやポンプ等の複
雑な形状物に適用することは困難であるという問題点が
ある。この問題点を解決する方法として、化学除染の適
用が考えられる。化学除染法を用いて、放射性金属廃棄
物を一般廃棄物並みに放射能レベルにまで除染するため
には、金属表面の溶解速度が速い除染液を用いる必要が
あり、硫酸（H2SO4）、塩酸（HCl）、硝酸（HNO3）等の
鉱酸を用いる方法が提案されている。However, since the electrolytic polishing decontamination method is a method of electrochemically dissolving and removing the contaminated portion of the surface, it is necessary to install the electrode so as to face the contaminated surface. There is a problem that it is difficult to apply to complicated shapes such as pumps and pumps. As a method of solving this problem, application of chemical decontamination can be considered. In order to decontaminate radioactive metal waste to the same level of radioactivity as general waste using the chemical decontamination method, it is necessary to use a decontamination solution with a fast dissolution rate on the metal surface, which requires sulfuric acid (H 2 Methods using mineral acids such as SO 4 ), hydrochloric acid (HCl), nitric acid (HNO 3 ) have been proposed.
しかしながら、このような鉱酸を用いる化学除染法にあ
っては、除染の進行に伴って、除染能力が低下するた
め、ある一定の除染能力に達した時点で中和処理し、そ
の後、固化処理を行わなければならない。従って、前記
した、強酸を電解液とした電解除染法と同様に二次廃棄
物が多量に発生するという問題があった。However, in such a chemical decontamination method using a mineral acid, the decontamination capacity decreases as the decontamination progresses, so neutralization is performed when a certain decontamination capacity is reached, After that, solidification must be performed. Therefore, there is a problem that a large amount of secondary waste is generated as in the above-mentioned electro-deletion dyeing method using a strong acid as an electrolytic solution.
従って、本発明は、前記の従来技術の欠点を解消し、放
射性物質取り扱い施設から発生する、あらゆる形状の放
射性金属廃棄物に適用でき、しかも二次廃棄物量の少な
い放射性金属廃棄物の除染方法を提供することにある。Therefore, the present invention eliminates the above-mentioned drawbacks of the prior art, can be applied to radioactive metal wastes of any shape generated from radioactive material handling facilities, and is a method for decontaminating radioactive metal wastes with a small amount of secondary waste. To provide.
問題点を解決するための手段及び作用 本発明は、直管、エルボ、ティーズ等の電極の設置が容
易な、単純な形状物は、中性塩溶液を電解液とした電解
研磨法で除染し、バルブ、ポンプ等の電極の設置が困難
な、複雑な形状物は、強酸を用いた化学除染法で除染
し、使用済みの化学除染液は、中和後、電解研磨除染の
電解液として再使用することによって、前記の問題点を
解決したものである。Means and Actions for Solving Problems The present invention has a simple shape in which electrodes such as straight pipes, elbows and teeth are easily installed, and a simple shape is decontaminated by an electrolytic polishing method using a neutral salt solution as an electrolytic solution. However, complicated shapes such as valves and pumps where it is difficult to install electrodes are decontaminated by the chemical decontamination method using a strong acid, and the used chemical decontamination solution is electrolytically decontaminated after neutralization. The above-mentioned problems have been solved by reusing it as the electrolytic solution.
すなわち、本発明による放射性金属廃棄物の除染方法
は、単純な形状物を中性塩溶液を用いる電解研磨法によ
って除染し、複雑な形状物を鉱酸を用いた化学除染法で
除染し、化学除染における使用済み液を中和した後、放
射性物質を分離除去し、電解研磨除染の電解液として再
使用することを特徴とする。That is, the method for decontaminating radioactive metal waste according to the present invention comprises decontaminating a simple shape by an electrolytic polishing method using a neutral salt solution, and decomposing a complicated shape by a chemical decontamination method using a mineral acid. It is characterized in that after dyeing and neutralizing a used solution in chemical decontamination, radioactive substances are separated and removed and reused as an electrolytic solution for electrolytic polishing decontamination.
次に、図面に基づいて本発明を詳述する。Next, the present invention will be described in detail with reference to the drawings.
図面は、本発明の除染方法の一実施態様を示すフローシ
ートである。The drawings are flow sheets showing an embodiment of the decontamination method of the present invention.
第１図に示した装置において、バルブ、ポンプ等の複雑
な形状の放射性金属廃棄物は、硫酸、塩酸、硝酸等の鉱
酸の溶液を除染液とした化学除染槽１で除染され、直
管、エルボ、ティーズ等の単純な形状の放射性金属廃棄
物は、硫酸ナトリウム、硝酸ナトリウム等の中性塩の溶
液を電解液とした電解研磨除染槽３で除染される。In the apparatus shown in FIG. 1, radioactive metal waste having complicated shapes such as valves and pumps is decontaminated in a chemical decontamination tank 1 using a solution of a mineral acid such as sulfuric acid, hydrochloric acid or nitric acid as a decontamination solution. The radioactive metal waste having a simple shape such as a straight pipe, an elbow, and teeth is decontaminated in the electrolytic polishing decontamination tank 3 using a solution of a neutral salt such as sodium sulfate and sodium nitrate as an electrolytic solution.
化学除染液中の鉱酸の濃度及び電解液中の中性液の濃度
は、これらの除染方法に通常使用される濃度であってよ
い。The concentration of the mineral acid in the chemical decontamination solution and the concentration of the neutral solution in the electrolytic solution may be the concentrations usually used in these decontamination methods.
電解研磨除染槽３内では、電解研磨除染時に溶解した金
属イオンが電解液中で金属水酸化物を形成し、この金属
水酸化物が浮遊している。これを分離するため、除染済
み液は固液分離槽４に導入される。In the electrolytic polishing decontamination tank 3, metal ions dissolved during electrolytic polishing decontamination form a metal hydroxide in the electrolytic solution, and the metal hydroxide is suspended. In order to separate this, the decontaminated liquid is introduced into the solid-liquid separation tank 4.
他方、化学除染槽１では、除染液として鉱酸を使用して
いるので、放射性金属はイオンとして溶存している。こ
の放射性金属イオンを液中から分離するため、使用済み
の化学除染液は中和槽２に導入され、アルカリ剤で中和
される。この際、溶存していた放射性金属イオンは、金
属水酸化物となり、液中の酸はアルカリ剤と反応して、
電解研磨除染の電解液中の中性塩濃度と同濃度の中性塩
水溶液が形成するように、アルカリ剤の添加量を調節す
る。こうして得た、中和後の除染液は、電解研磨除染の
使用済み液と同様に、固液分離槽４に導入される。固液
分離槽４で分離された上澄液は、電解研磨除染槽３へ返
送され、再利用され、濃縮スラッジは固化処理工程５に
導入される。On the other hand, in the chemical decontamination tank 1, since a mineral acid is used as a decontamination solution, radioactive metals are dissolved as ions. In order to separate the radioactive metal ions from the liquid, the used chemical decontamination liquid is introduced into the neutralization tank 2 and neutralized with an alkaline agent. At this time, the dissolved radioactive metal ion becomes metal hydroxide, and the acid in the liquid reacts with the alkaline agent,
The addition amount of the alkaline agent is adjusted so that a neutral salt aqueous solution having the same concentration as the neutral salt concentration in the electrolytic solution for electrolytic polishing decontamination is formed. The neutralized decontamination liquid thus obtained is introduced into the solid-liquid separation tank 4 in the same manner as the used liquid for electrolytic polishing decontamination. The supernatant liquid separated in the solid-liquid separation tank 4 is returned to the electrolytic polishing decontamination tank 3 and reused, and the concentrated sludge is introduced into the solidification treatment step 5.
実施例 次に、実施例に基づいて本発明を詳述するが、本発明は
これに限定されるものではない。EXAMPLES Next, the present invention will be described in detail based on examples, but the present invention is not limited thereto.
実施例１ この例では、放射性物質で汚染されたポンプ及び直管を
図面に示したフローシートにより除染した。Example 1 In this example, a pump and a straight pipe contaminated with radioactive materials were decontaminated by the flow sheet shown in the drawing.
ポンプ（除染面積:1m2）を1.8モル/lのH2SO4溶液を除染
液とした化学除染槽１中で下記の条件で除染し、直管
（除染面積:10m2）を0.9モル/lのNa2SO4溶液を電解液と
した電解研磨除染槽３中で下記の条件下に除染した。A pump (decontamination area: 1 m 2 ) was decontaminated under the following conditions in a chemical decontamination tank 1 using 1.8 mol / l H 2 SO 4 solution as a decontamination solution, and a straight pipe (decontamination area: 10 m 2 Was decontaminated under the following conditions in an electrolytic polishing decontamination tank 3 using a 0.9 mol / l Na 2 SO 4 solution as an electrolytic solution.
化学除染の条件： 温度 80℃ 時間 1時間 電解研磨除染の条件： 対極 炭素鋼 電流密度 0.3A/cm2 電解時間 30分 化学除染槽１からの使用済み除染液を中和槽２内に導入
し、3.6モル/lの水酸化ナトリウム水溶液で中和した。
この際、溶存していた放射性金属イオンは金属水酸化物
となり、また、1.8モル/lのH2SO4と3.6モル/lのNaOHが
反応して、電解研磨除染の電解液と同じ0.9モル/lのNa2
SO4溶液が生成した。このNa2SO4溶液を固液分離後に電
解研磨除染槽へ循環させた。生じた濃縮スラッジの量
は、400lであった。Chemical decontamination conditions: Temperature 80 ° C time 1 hour Electropolishing decontamination conditions: Counter electrode carbon steel Current density 0.3A / cm 2 Electrolysis time 30 minutes Neutralization tank 2 for used decontamination solution from chemical decontamination tank 1 It was introduced into the reaction vessel and neutralized with a 3.6 mol / l sodium hydroxide aqueous solution.
At this time, the dissolved radioactive metal ion becomes a metal hydroxide, and 1.8 mol / l H 2 SO 4 and 3.6 mol / l NaOH react with each other, which is the same as the electrolytic solution for electrolytic polishing decontamination. Mol / l Na 2
SO 4 solution formed. This Na 2 SO 4 solution was circulated to the electrolytic polishing decontamination tank after solid-liquid separation. The amount of concentrated sludge produced was 400 l.
この実施例においては、硫酸の濃度を1.8モル/l、水酸
化ナトリウムの濃度を3.6モル/lとしたが、中和後に電
解研磨除染に使用可能な硫酸ナトリウム濃度になれば、
他の濃度を使用することができる。In this example, the concentration of sulfuric acid was 1.8 mol / l, the concentration of sodium hydroxide was 3.6 mol / l, but if the concentration of sodium sulfate that can be used for electrolytic polishing decontamination after neutralization becomes,
Other concentrations can be used.
また、電解研磨除染の電解液として硫酸ナトリウム、化
学除染の除染液として硫酸を用いたが、本発明はこれに
限定されるものではなく、化学除染の除染液は、電解研
磨除染の電解液に使用するナトリウム塩と同種の陰イオ
ン種を有する鉱酸を使用することができる。Further, sodium sulfate was used as an electrolytic solution for electrolytic polishing decontamination, and sulfuric acid was used as a decontaminating solution for chemical decontamination, but the present invention is not limited to this, and the decontaminating solution for chemical decontamination is electrolytic polishing. A mineral acid having the same anionic species as the sodium salt used in the decontaminating electrolyte can be used.
発明の効果 本発明によれば、あらゆる形状の放射性金属廃棄物を一
つの処理系統で除染することができ、バルブやポンプ等
の複雑な形状物を化学除染した後の使用済み液を、中和
した後に、電解研磨除染の電解液として再利用できるの
で、二次廃棄物量を大幅に減少させることができる。EFFECTS OF THE INVENTION According to the present invention, radioactive metal wastes of any shape can be decontaminated by one treatment system, and the used liquid after chemical decontamination of complicated shapes such as valves and pumps can be After neutralization, it can be reused as an electrolytic solution for electrolytic polishing decontamination, so that the amount of secondary waste can be greatly reduced.
図面は、本発明方法の一実施態様を示すフローシートで
ある。 符号の説明 １……化学除染槽、２……中和槽、３……電解研磨除染
槽、４……固液分離槽、５……固化処理工程The drawings are flow sheets showing one embodiment of the method of the present invention. Explanation of symbols 1 ... Chemical decontamination tank, 2 ... Neutralization tank, 3 ... Electropolishing decontamination tank, 4 ... Solid-liquid separation tank, 5 ... Solidification treatment process
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山寺 利夫 東京都千代田区内神田１丁目１番14号 日 立プラント建設株式会社内 審査官 石井 良和 (56)参考文献 特開 昭59−136189（ＪＰ，Ａ) 特開 昭59−15900（ＪＰ，Ａ) 特開 昭60−105998（ＪＰ，Ａ) 特開 昭60−35297（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Yamadera 1-1-14 Uchikanda, Chiyoda-ku, Tokyo Yoshikazu Ishii, Inspector, Hitachi Plant Construction Co., Ltd. (56) Reference JP-A-59-136189 (JP) , A) JP 59-15900 (JP, A) JP 60-105998 (JP, A) JP 60-35297 (JP, A)
Claims (2)
な形状の放射性金属廃棄物を除染するため、単純な形状
物を中性塩溶液を用いる電解研磨法によって除染し、複
雑な形状物を鉱酸を用いた化学除染法で除染し、化学除
染における使用済み液を中和した後、放射性物質を分離
除去し、電解研磨除染の電解液として再使用することを
特徴とする放射性金属廃棄物の除染方法。1. To decontaminate radioactive metal wastes of various shapes generated from radioactive material handling facilities, simple shapes are decontaminated by an electrolytic polishing method using a neutral salt solution, and complicated shapes are removed. Characterized by decontaminating by chemical decontamination method using mineral acid, neutralizing the used solution in chemical decontamination, separating and removing radioactive substances, and reusing as electrolytic solution for electrolytic polishing decontamination Decontamination method for radioactive metal waste.
化学除染の除染液が電解除染の電解液と同種の陰イオン
を有する鉱酸であり、中和剤として水酸化ナトリウム溶
液を用いる特許請求の範囲第１項記載の除染方法。2. An electrolytic solution for electro-deletion dye is a sodium salt,
The decontamination method according to claim 1, wherein the decontamination solution for chemical decontamination is a mineral acid having the same type of anion as the electrolytic solution for electro-decontamination and a sodium hydroxide solution is used as a neutralizing agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15192486A JPH0690309B2 (en) | 1986-06-27 | 1986-06-27 | Decontamination method for radioactive metal waste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15192486A JPH0690309B2 (en) | 1986-06-27 | 1986-06-27 | Decontamination method for radioactive metal waste |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS638599A JPS638599A (en) | 1988-01-14 |
| JPH0690309B2 true JPH0690309B2 (en) | 1994-11-14 |
Family
ID=15529173
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15192486A Expired - Lifetime JPH0690309B2 (en) | 1986-06-27 | 1986-06-27 | Decontamination method for radioactive metal waste |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0690309B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7139591B2 (en) | 1993-10-13 | 2006-11-21 | Dataquill Limited | Hand held telecommunications and data entry device |
-
1986
- 1986-06-27 JP JP15192486A patent/JPH0690309B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7139591B2 (en) | 1993-10-13 | 2006-11-21 | Dataquill Limited | Hand held telecommunications and data entry device |
| US7505785B2 (en) | 1993-10-13 | 2009-03-17 | Dataquill Limited | Data entry systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS638599A (en) | 1988-01-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4537666A (en) | Decontamination using electrolysis | |
| EP0789831B1 (en) | Decontamination process | |
| EP0682806B1 (en) | Process for the treatment of particulate material | |
| JPH0153440B2 (en) | ||
| US4217192A (en) | Decontamination of metals using chemical etching | |
| EP0125401B1 (en) | Method for decontaminating metals contaminated with radioactive substances | |
| US5752206A (en) | In-situ decontamination and recovery of metal from process equipment | |
| JP4753141B2 (en) | Method for dissolving and separating uranium using ionic liquid, and method for recovering uranium using the same | |
| US4701246A (en) | Method for production of decontaminating liquid | |
| EP0859671B1 (en) | Method for decontamination of nuclear plant components | |
| JPH0466187A (en) | Treatment of waste water containing heavy metal and organic matter | |
| JPH0690309B2 (en) | Decontamination method for radioactive metal waste | |
| US7384529B1 (en) | Method for electrochemical decontamination of radioactive metal | |
| US11342092B2 (en) | Electrolyte for electrochemical decontamination and preparation method and application thereof | |
| US5102511A (en) | Method of decontaminating radioactive metallic wastes | |
| JPS61231496A (en) | Decontamination method for radioactive metal waste | |
| KR20220053270A (en) | Decontaminating method for removal of the radioactive oxide layer | |
| JPS62130396A (en) | How to remove oxide film containing radioactive materials | |
| JPS603593A (en) | Method of electrolytically decontaminating radioactive metallic waste | |
| JPH01138497A (en) | Decontamination method for radioactive metal waste | |
| JP2002267798A (en) | Dissolving and decomtamination method | |
| JPH01193700A (en) | Decontamination method for radioactive metal waste | |
| Partridge et al. | Chemical decontamination of metals | |
| JPH0527092A (en) | Decontamination method for radioactive metal waste | |
| JPS647359B2 (en) |