JPH09159798A - Bubble decontamination and method for treating decontamination waste liquid - Google Patents
Bubble decontamination and method for treating decontamination waste liquidInfo
- Publication number
- JPH09159798A JPH09159798A JP32335695A JP32335695A JPH09159798A JP H09159798 A JPH09159798 A JP H09159798A JP 32335695 A JP32335695 A JP 32335695A JP 32335695 A JP32335695 A JP 32335695A JP H09159798 A JPH09159798 A JP H09159798A
- Authority
- JP
- Japan
- Prior art keywords
- decontamination
- waste liquid
- ozone
- foam
- defoaming
- 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
- Physical Water Treatments (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、原子力施設や一般
産業で使用されている大型容器および塔槽類、とくに放
射性物質で汚染された機器や配管の内面を薬剤を用いて
除染し、続いてその廃液を処理する一連の工程からなる
方法に関する。TECHNICAL FIELD The present invention relates to the decontamination of a large container and a tower tank used in a nuclear facility or a general industry, especially an inner surface of a device or a pipe contaminated with a radioactive substance with a chemical, The present invention relates to a method comprising a series of steps for treating the waste liquid.
【０００２】[0002]
【従来の技術】原子力発電所の塔槽類やポンプ、配管な
どの内面には、運転中に放射性物質、とくに「クラッ
ド」とよばれる酸化鉄を主体とするものが付着するの
で、その除去のために化学除染を行なっている。 化学
除染には、難溶性クラッドがある場合は過マンガン酸カ
リのカセイソーダ溶液で前処理した後、硫酸のような強
酸やカセイソーダ溶液のような強アルカリを用いること
もあるが、除染対象を損なわないよう配慮して、シュウ
酸、クエン酸のような有機酸や、ＥＤＴＡのようなキレ
ート剤を使用することが多い。2. Description of the Prior Art Radioactive materials, especially those mainly composed of iron oxide called "clad", adhere to the inner surfaces of towers, pumps, and piping of nuclear power plants during operation. Therefore, chemical decontamination is performed. For chemical decontamination, if there is a sparingly soluble clad, after pretreatment with a caustic soda solution of potassium permanganate, a strong acid such as sulfuric acid or a strong alkali such as caustic soda solution may be used. In order not to damage it, organic acids such as oxalic acid and citric acid, and chelating agents such as EDTA are often used.
【０００３】このような有機化合物を除染剤として使用
した場合、放射性物質を含有する廃液を処理するため
に、有機化合物を酸化分解して、炭酸ガス、水、あるい
は窒素ガス等に変えて大気放出可能にしたのち、廃液を
濃縮減容し、固化処理することが行なわれている。When such an organic compound is used as a decontaminating agent, in order to treat a waste liquid containing a radioactive substance, the organic compound is oxidatively decomposed and converted into carbon dioxide gas, water, nitrogen gas or the like, and the atmosphere. After making it possible to discharge, the waste liquid is concentrated and reduced in volume, and then solidified.
【０００４】有機化合物の酸化分解には過酸化水素やオ
ゾンを使用することが試みられ、とくに紫外線の照射下
に酸化を行なう提案が多い。 たとえば特開昭６０−８
２８９２号は、有機酸を含む化学除染廃液を多孔質濾過
膜で濾過処理したのち、紫外線照射下にオゾンを吹き込
んで有機酸を炭酸ガスと水とにするものであり、特開平
５−２０９９９７号はキレート剤を含有する除染廃液に
オゾンを添加して撹拌しつつ紫外線を照射して、キレー
ト剤を酸化分解するものである。For the oxidative decomposition of organic compounds, it has been attempted to use hydrogen peroxide or ozone, and many proposals have been made to oxidize particularly under the irradiation of ultraviolet rays. For example, JP-A-60-8
No. 2892 discloses a chemical decontamination waste liquid containing an organic acid, which is filtered through a porous filtration membrane, and then ozone is blown into the organic acid to convert it into carbon dioxide gas and water. No. 1 is to oxidize and decompose the chelating agent by adding ozone to the decontamination waste liquid containing the chelating agent and irradiating it with ultraviolet rays while stirring.
【０００５】一方、除染液の量を少くして効果を得よう
とする手法として、泡除染法が知られている。 泡除染
法は化学除染剤と界面活性剤とを溶解した水溶液に空気
を吹き込んで泡立てたものを、除染対象に送り込んで接
触させることにより、除染を行なう。 出願人は、放射
性物質で汚染された円筒形の容器の内壁の除染に泡除染
法を適用し、これに電解研磨の原理を組み合わせた装置
を完成し、すでに提案した（特公平６−４０１５４
号）。On the other hand, a foam decontamination method is known as a method for reducing the amount of the decontamination solution to obtain an effect. In the foam decontamination method, decontamination is performed by blowing air into an aqueous solution in which a chemical decontaminating agent and a surfactant are dissolved and foaming the resulting mixture, and sending the foamed material to a decontamination target to bring them into contact with each other. The applicant has applied a bubble decontamination method to decontaminate the inner wall of a cylindrical container contaminated with radioactive substances, has completed a device combining this with the principle of electrolytic polishing, and has already proposed it (Japanese Patent Publication No. 6- 40154
issue).
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、泡除
染法と紫外線照射下のオゾン酸化とを連続して実施する
ことができ、それによって、除染および除染廃液の処理
に関与する物質の種類および量を最少限に抑え、放射性
物質等の除去を安全かつ有利に行なうことのできる方法
を提供することにある。DISCLOSURE OF THE INVENTION The object of the present invention is to carry out a bubble decontamination method and an ozone oxidation under ultraviolet irradiation in succession, thereby being involved in decontamination and treatment of a decontamination waste liquid. It is an object of the present invention to provide a method capable of safely and advantageously removing radioactive substances and the like by minimizing the types and amounts of substances to be removed.
【０００７】[0007]
【課題を解決するための手段】本発明の泡除染および除
染廃液処理の方法は、汚れた大型容器および塔槽類を含
む機器・配管の内面を化学除染し、続いてその除染廃液
を処理する方法であって、除染剤および起泡剤を溶解し
た水溶液中にオゾンを含有する空気または酸素ガスを吹
き込んで泡除染液を形成し、この泡除染液を除染すべき
機器・配管内に送り込んで除染を行ない、除染を終って
排出される泡除染廃液を廃液処理槽へ受け入れ、残存す
るオゾンの存在下に紫外線を照射することによって泡除
染廃液中の有機化合物を酸化分解して、炭酸ガス、水お
よび窒素ガスに無機化し、排ガスはオゾン吸着装置を通
して放出することからなる。The method of the present invention for decontaminating bubbles and treating waste liquid for decontamination comprises chemically decontaminating the inner surfaces of equipment and pipes including dirty large containers and tower tanks, and subsequently decontaminating the same. A method for treating waste liquid, which comprises blowing air or oxygen gas containing ozone into an aqueous solution in which a decontaminating agent and a foaming agent are dissolved to form a defoaming solution, and decontaminating this defoaming solution. Into the defoaming waste liquid, the defoaming waste liquid discharged after the decontamination is received into the waste liquid treatment tank and irradiated with ultraviolet rays in the presence of residual ozone. The oxidative decomposition of the organic compound (1) is converted into carbon dioxide gas, water and nitrogen gas, and the exhaust gas is discharged through an ozone adsorption device.
【０００８】除染剤としては、従来から使用されている
有機酸としてのシュウ酸やクエン酸、ギ酸、ヒドロキシ
ル酢酸、マロン酸、アスコルビン酸、グルコン酸、また
キレート剤としてのＥＤＴＡ、ピコリン酸などが使用で
きる。 さらに、硫酸、リン酸、硝酸等の無機酸も使用
できる。As decontaminating agents, oxalic acid, citric acid, formic acid, hydroxylacetic acid, malonic acid, ascorbic acid, gluconic acid as organic acids which have been conventionally used, and EDTA and picolinic acid as chelating agents are used. Can be used. Furthermore, inorganic acids such as sulfuric acid, phosphoric acid and nitric acid can also be used.
【０００９】オゾンは、空気またはＰＳＡ法や膜分離法
などによって酸素濃度を高めた酸素富化空気の中で、無
声放電を行なって生成させる。 市販のオゾン発生装置
を使用して、オゾン濃度１００〜１２０g／Nm3程度のオ
ゾン含有ガスが、容易に得られる。Ozone is generated by performing silent discharge in air or oxygen-enriched air whose oxygen concentration is increased by the PSA method, the membrane separation method, or the like. An ozone-containing gas having an ozone concentration of about 100 to 120 g / Nm 3 can be easily obtained by using a commercially available ozone generator.
【００１０】除染条件は、除染対象に許容される条件
や、所望する除染の程度によって決定する。 多くの場
合、前記した除染剤を濃度０．１〜５重量％と、適量の
界面活性剤とを溶解した除染液を温度４０〜８０℃に加
熱して使用し、これにオゾン含有ガスを吹き込んで泡径
０．５〜２mmの泡からなる泡除染液としたものを、除染
対象の機器・配管の中へゆっくり送り込み、循環させて
６〜２４時間接触させればよい。 温度が低いと除染効
果が弱く、一方、高すぎると起泡力が劣る。 また、泡
が小さ過ぎると泡としての機能が劣り、反対に大き過ぎ
ると崩壊しやすくなる。The decontamination conditions are determined according to the conditions allowed for decontamination and the desired degree of decontamination. In many cases, a decontamination solution in which the above-mentioned decontamination agent is dissolved in a concentration of 0.1 to 5% by weight and an appropriate amount of a surfactant is heated to a temperature of 40 to 80 ° C., and an ozone-containing gas is used. What is necessary is just to blow in and make the foam decontamination liquid which consists of bubbles with a diameter of 0.5-2 mm slowly into the equipment and piping for decontamination, circulate, and make it contact for 6 to 24 hours. If the temperature is low, the decontamination effect will be weak, while if it is too high, the foaming power will be poor. On the other hand, if the bubbles are too small, the function as bubbles is inferior, while if they are too large, they tend to collapse.
【００１１】紫外線照射による、残存オゾンを利用した
除染廃液中の有機化合物の酸化分解は、既知の技術に従
って実施できる。 酸化分解の進行につれて泡が破壊
し、液は泡を含まないものとなる。 このとき、分解槽
内に溜った廃液をポンプで槽の上部へ循環させると、分
解に要する時間を短縮することができて有利である。泡
から放出されたガス中にはなお相当量のオゾンが含まれ
ているから、オゾン吸着装置を経て放出し、液は必要な
濃縮減容工程を経て、アスファルト固化やセメント固化
等の手段で固化し、処理を終る。The oxidative decomposition of the organic compound in the decontamination waste liquid utilizing the residual ozone by the irradiation of ultraviolet rays can be carried out according to a known technique. As the oxidative decomposition progresses, the bubbles break, and the liquid becomes bubble-free. At this time, if the waste liquid accumulated in the decomposition tank is circulated to the upper part of the tank by a pump, the time required for decomposition can be shortened, which is advantageous. The gas released from the bubbles still contains a considerable amount of ozone, so it is released through an ozone adsorption device, and the liquid is solidified by means such as asphalt solidification and cement solidification through the necessary concentration and volume reduction process. Then, the process ends.
【００１２】[0012]
【作用】従来の泡除染と紫外線照射下のオゾンによる有
機除染剤の酸化分解とを続いて行なおうとすると、いっ
たん泡除染廃液にシリコーンやエタノールのような消泡
剤を加えて泡をつぶしたのち、改めてオゾン含有空気を
吹き込んで紫外線照射を行なう、という手順に従わなけ
ればならなかった。 これに対し本発明では、起泡にオ
ゾン含有ガスを使用し、除染後の泡除染廃液中に残存し
ているオゾンを利用して酸化分解を行なうので、上記の
ようなわずらわしい手順を踏む必要がなく、かつ消泡剤
も不要である。[Function] When the conventional foam decontamination and the oxidative decomposition of the organic decontamination agent by ozone under UV irradiation are attempted successively, once the defoaming waste liquid is added with a defoaming agent such as silicone or ethanol. After crushing it, it was necessary to follow the procedure of blowing ozone-containing air and irradiating it with ultraviolet rays. On the other hand, in the present invention, the ozone-containing gas is used for foaming, and the oxidative decomposition is carried out by utilizing the ozone remaining in the decontaminating foam decontamination waste liquid, so that the troublesome procedure as described above is taken. No need, and no antifoaming agent.
【００１３】除染液に直接オゾンを接触させることは、
除染剤の効果を損う心配（酸化力のあるオゾンが還元剤
であるシュウ酸と反応する可能性など）もあって、これ
まで試みられたことがなかった。 発明者らは、実験の
結果、オゾン含有ガスで除染液の起泡を行なっても、除
染段階ではオゾンにより除染剤の作用が損なわれること
はなく、難溶性のスピネル構造のクラッド（たとえばＣ
ｒＦｅ2Ｏ4）やクロム酸化物の溶解を促進するという事
実を見出し、一方でそのオゾンが、紫外線照射を受けた
ときには残った有機化合物の酸化分解に役立つことを確
認して、本発明に至った。The direct contact of ozone with the decontamination solution is
This has never been attempted because there is concern that the effect of the decontaminating agent will be impaired (such as the possibility that ozone, which has oxidizing power, will react with oxalic acid, which is a reducing agent). As a result of the experiment, the inventors have found that even if the decontamination liquid is bubbled with an ozone-containing gas, the action of the decontamination agent is not impaired by ozone in the decontamination stage, and the sparingly soluble spinel structure clad ( For example C
It was found that the ozone promotes the dissolution of rFe 2 O 4 ) and chromium oxide, and on the other hand, the ozone was found to be useful for the oxidative decomposition of the remaining organic compounds when it was irradiated with ultraviolet rays, leading to the present invention. It was
【００１４】従って本発明は、泡除染技術が一般的にも
つ利益をすべて享受できる。 すなわち、（１）除染液
が少量（泡を使用しない場合の１／１０〜１／２０程
度）ですむこと、（２）泡が連続的に送り込まれるため
被洗浄面に接触する除染液が絶えず更新されること、
(３)クラッド剥離（微量の水素ガスが発生することによ
る物理的剥離）は起らず、剥離物のクレビス部蓄積がな
いこと、（４）除染されたスラッジや浮遊固形分が泡に
包含されて沈降しない（浮遊選鉱法の原理）こと、
（５）界面活性剤のもつ膨潤効果により除染効果が高ま
ること、および（６）油脂分や微生物などが付着してい
た場合、アルカリ洗浄のような前処理をしなくても、界
面活性剤やオゾンの作用でそれらが除去できること、な
どである。The present invention thus enjoys all the benefits generally associated with foam decontamination techniques. That is, (1) a small amount of decontamination solution (about 1/10 to 1/20 of the case where no foam is used) is required, and (2) decontamination solution that contacts the surface to be cleaned because bubbles are continuously fed. Is constantly updated,
(3) No clad peeling (physical peeling due to generation of a trace amount of hydrogen gas), no accumulation of clevis in the peeled product, (4) decontaminated sludge or suspended solids contained in bubbles Is not settled (the principle of the flotation method),
(5) The decontamination effect is enhanced by the swelling effect of the surfactant, and (6) if oil and fat or microorganisms are attached, the surfactant can be treated without pretreatment such as alkali washing. And that they can be removed by the action of ozone.
【００１５】除染廃液の処理に当って、泡液に含まれた
金属酸化物や浮遊固形分は、有機化合物の酸化分解にと
って触媒のように作用し、反応を速くする。 酸化分解
の進行は泡の破壊をひきおこし、それによって金属酸化
物その他の固形分は濃縮されて行き、そのことがまた泡
の破壊を促すから、廃液の泡は容易に消える。In the treatment of the decontamination waste liquid, the metal oxides and suspended solids contained in the foam liquid act as a catalyst for the oxidative decomposition of the organic compound, and accelerate the reaction. The progress of oxidative decomposition causes the destruction of the bubbles, whereby metal oxides and other solids are concentrated, which also promotes the destruction of the bubbles, so that the bubbles of the waste liquid disappear easily.
【００１６】泡液に紫外線を照射すればオゾンによる酸
化分解がはじまることは、除染に続いて直ちに、つまり
除染作業から排出される泡除染廃液をそのまま処理でき
ることを意味し、前述の消泡を必要としないことに加え
て、廃液の一時的な受けタンクのような設備も不要であ
る。 従って本発明は、設備としてわずかなものを付加
すれば実施できる。The fact that the oxidative decomposition by ozone begins when the foam liquid is irradiated with ultraviolet rays means that the foam decontamination waste liquid discharged from the decontamination work can be treated immediately after the decontamination. In addition to the fact that no bubbles are required, no equipment such as a temporary receiving tank for waste liquid is required. Therefore, the present invention can be implemented by adding a small amount of equipment.
【００１７】[0017]
【実施例】図１に示す構成の装置を組み立てた。 除染
液調製槽（１）に有機化合物の除染剤および水を入れて
溶解し、所定量の界面活性剤を加えて泡発生槽（３）に
送る。 一方、オゾン発生装置（２）でオゾン含有空気
またはオゾン含有酸素をつくり、これを泡発生槽内に導
いて、微細な泡を多数発生させる。 泡除染液を泡除染
槽（４）に移し、そこで除染作用をする。 泡除染槽
（４）の底部に溜まる除染液は、泡発生槽（３）へ循環
させる。 この実施例では、除染対象物（５）として、
鋼板上にクラッドにシュミレートしたＦｅ3Ｏ4（マグネ
タイト）を付着させたものを使用し、除染剤による表層
溶解で除染した。 つまり、酸化物のままスラッジとし
て剥離させることなく、溶解除去した。 従って、この
実施例においては除染後の泡液中には固形分がほとんど
含まれていない。 しかし、実際に機器・配管の除染を
行なった場合、泡除染槽内の泡液は、図２に拡大して示
すように、金属酸化物などの固形分を含む。EXAMPLE An apparatus having the structure shown in FIG. 1 was assembled. A decontamination liquid preparation tank (1) is charged with a decontaminating agent for an organic compound and water, and a predetermined amount of a surfactant is added to the decontamination solution preparation tank (1) and the mixture is sent to a bubble generation tank (3). On the other hand, ozone-containing air or ozone-containing oxygen is produced in the ozone generator (2) and introduced into the bubble generation tank to generate a large number of fine bubbles. The foam decontamination solution is transferred to the foam decontamination tank (4), where it is decontaminated. The decontamination liquid accumulated at the bottom of the bubble decontamination tank (4) is circulated to the bubble generation tank (3). In this example, as the decontamination target (5),
A sheet of steel sheet to which simulated Fe 3 O 4 (magnetite) was attached was used, and decontamination was performed by surface layer dissolution with a decontaminating agent. That is, the oxide was dissolved and removed without being separated as sludge as the oxide. Therefore, in this example, the foam liquid after decontamination contains almost no solid content. However, when decontamination of the equipment and piping is actually performed, the foam liquid in the foam decontamination tank contains solid components such as metal oxides as shown in an enlarged view in FIG.
【００１８】除染を行なって効力を失った泡除染液は、
廃液処理槽（６）へ導き、紫外線ランプ（７）から紫外
線を照射して、ランプ近辺の泡廃液中で連続的に酸化反
応を起させ、泡を破壊する。 排気はオゾン吸着塔
（８）でオゾンを除去したのち、放出する。 廃液は、
その中の有機化合物が酸化分解され、泡が失なわれて、
無機物を溶解した廃液となって廃液受槽（９）に流下す
る。Foam decontamination liquid which has lost its effect after decontamination is
It is led to the waste liquid treatment tank (6) and irradiated with ultraviolet rays from an ultraviolet lamp (7) to continuously cause an oxidation reaction in the foam waste liquid near the lamp to destroy the bubbles. The exhaust gas is discharged after ozone is removed by the ozone adsorption tower (8). The waste liquid is
The organic compounds in it are oxidatively decomposed, the bubbles are lost,
It becomes a waste liquid in which inorganic substances are dissolved and flows down to the waste liquid receiving tank (9).
【００１９】〔実施例１〕除染剤としてクエン酸を０．
５重量％の濃度で使用した。 界面活性剤を加えた除染
液５００mlに、オゾン供給量２ｇ／ｌ・hrの割合でオゾ
ン含有空気を８時間吹き込んで泡径約１．５mmの泡除染
液とし、温度を７０℃に保って、上記の溶解除染を８時
間にわたって行なった。Example 1 Citric acid was used as a decontaminating agent in an amount of 0.
Used at a concentration of 5% by weight. Ozone-containing air was blown into a decontamination solution (500 ml) containing a surfactant at a rate of 2 g / l · hr for 8 hours to form a defoaming solution with a bubble diameter of about 1.5 mm and the temperature was maintained at 70 ° C. Then, the above-mentioned dissolution decontamination was carried out for 8 hours.
【００２０】除染時間の進行につれて増大する、溶解に
より除去されたＦｅ3Ｏ4の割合を図３に示す。 図３の
縦軸の溶解率は、（溶解したＦｅ量／溶解を想定される
全Ｆｅ量）×１００（％）であらわされる。FIG. 3 shows the proportion of Fe 3 O 4 removed by dissolution, which increases with the progress of decontamination time. The dissolution rate on the vertical axis of FIG. 3 is represented by (dissolved Fe amount / total Fe amount assumed to be dissolved) × 100 (%).
【００２１】除染後の廃泡に対しては、１００Ｗ水銀ラ
ンプから紫外線を照射した。 液中の有機物の量を測定
し、（分解後ＴＯＣ濃度／分解前ＴＯＣ濃度）×１００
（％）として、有機物未分解率を算出した。 分解時間
の進行に伴う分解率の変化を、図４に示す。The waste foam after decontamination was irradiated with ultraviolet rays from a 100 W mercury lamp. Measure the amount of organic matter in the liquid, (TOC concentration after decomposition / TOC concentration before decomposition) x 100
(%), The undegraded organic matter rate was calculated. The change in the decomposition rate with the progress of the decomposition time is shown in FIG.
【００２２】図３の結果から、除染時間８時間で約９３
％のＦｅ3Ｏ4が除去されたことがわかり、また図４の結
果から、分解時間３時間でほぼ１００％の有機物が分解
したことがわかる。From the results shown in FIG. 3, it is possible to obtain about 93 after 8 hours of decontamination.
It was found that 100% of Fe 3 O 4 was removed, and from the result of FIG. 4, it was found that almost 100% of the organic substances were decomposed in the decomposition time of 3 hours.
【００２３】〔実施例２〕除染剤としてシュウ酸および
クエン酸をそれぞれ０．５重量％の濃度で使用し、オゾ
ンを２．５ｇ／ｌ・hrの割合で供給した泡径約１．５mm
の泡除染液を用意した。 同じく温度７０℃で実施例１
と同様にＦｅ3Ｏ4を溶解する試験と、除染後の廃液処理
とを続けて行なった。[Example 2] Oxalic acid and citric acid were used as decontaminating agents at a concentration of 0.5% by weight respectively, and ozone was supplied at a rate of 2.5 g / l · hr.
Was prepared. Example 1 at the same temperature of 70 ° C.
Similarly to the above, the test for dissolving Fe 3 O 4 and the treatment of the waste liquid after decontamination were performed successively.
【００２４】図５に除染効果を示し、図６に分解処理の
結果を示す。 前者から、除染時間６時間で約９５％の
Ｆｅ3Ｏ4が除去されたこと、後者から３時間で廃液の酸
化分解が行なわれたことが、それぞれ明らかである。FIG. 5 shows the decontamination effect, and FIG. 6 shows the result of the decomposition treatment. It is clear from the former that about 95% of Fe 3 O 4 was removed in 6 hours of decontamination, and the oxidative decomposition of the waste liquid was performed in 3 hours from the latter.
【００２５】〔実施例３〕除染剤としてクエン酸および
ＥＤＴＡをそれぞれ０．２５重量％の濃度で使用し、オ
ゾン供給量３．０ｇ／ｌ・hrで、泡径約１．５mmの泡除
染液を用意した。除染および除染廃液の処理は、実施例
１および２と同じ。Example 3 Citric acid and EDTA were used as decontaminating agents at a concentration of 0.25% by weight, respectively, and ozone was supplied at a rate of 3.0 g / l · hr, and a defoaming agent with a bubble diameter of about 1.5 mm was removed. A dye solution was prepared. The decontamination and the treatment of the decontamination waste liquid are the same as in Examples 1 and 2.
【００２６】図７に除染効果を、図８に分解処理の結果
を示す。 前者からは除染時間６時間で約９８％のＦｅ
3Ｏ4を除去できたこと、後者からは３時間で約９５％の
有機物の分解ができたことがわかる。FIG. 7 shows the decontamination effect, and FIG. 8 shows the result of the decomposition treatment. From the former, about 98% Fe was obtained after 6 hours of decontamination.
It can be seen that 3 O 4 could be removed, and from the latter, about 95% of organic substances could be decomposed in 3 hours.
【００２７】[0027]
【発明の効果】放射性物質等で汚染された機器・配管の
類を、本発明に従って除染するとともにその除染廃液を
処理すれば、除染を促進し、泡除染の利益を全面的に享
受し、かつオゾン＋紫外線照射による有機物の酸化分解
を利用した廃液処理の効果をもあわせて得られることは
もちろんであって、その上で、一貫した作業で除染およ
び廃液処理が行なえるという効果がある。 除染対象物
に付着しているクラッドとほぼ当量の除染剤の使用でよ
く、また効果のある除染剤をムダにすることがないの
で、使用する薬剤の種類および量は最少限度に止めるこ
とができ、また消泡剤のようなものを使用する必要はな
く、従って、二次廃棄物量は増大しない。これととも
に、設備的にも除染廃液の受けタンクが不要である。
これらの諸要因は、あいまって除染および廃液処理のコ
ストを低減するのに役立つ。EFFECTS OF THE INVENTION By decontaminating equipment and pipes contaminated with radioactive substances and the like according to the present invention and treating the decontamination waste liquid, decontamination is promoted and the benefit of foam decontamination is fully achieved. It is of course possible to enjoy the effect of waste liquid treatment utilizing the oxidative decomposition of organic substances by ozone and UV irradiation, and on top of that, decontamination and waste liquid treatment can be performed in a consistent work. effective. It is sufficient to use the same amount of decontaminating agent as the clad adhering to the object to be decontaminated, and the effective decontaminating agent is not wasted, so the type and amount of chemicals used should be kept to a minimum. Is possible, and there is no need to use something like a defoamer, so the amount of secondary waste is not increased. At the same time, the receiving tank for the decontamination waste liquid is not necessary in terms of equipment.
These factors together help to reduce the cost of decontamination and waste treatment.
【図１】 本発明の泡除染および除染廃液の処理システ
ムを概念的に示すとともに、実施例で使用した装置の構
成を示す図。FIG. 1 is a diagram conceptually showing a foam decontamination system and a decontamination waste liquid treatment system of the present invention, and also showing a configuration of an apparatus used in Examples.
【図２】 図１の泡除染槽内で除染を行なった泡液の拡
大図。2 is an enlarged view of a foam liquid decontaminated in the foam decontamination tank of FIG.
【図３】 本発明の実施例１において、クラッドにシミ
ュレートさせたＦｅ3Ｏ4の溶解除染の進行状況を示すグ
ラフ。FIG. 3 is a graph showing the progress of dissolution decontamination of Fe 3 O 4 simulated in the clad in Example 1 of the present invention.
【図４】 本発明の実施例１において、除染廃液の酸化
分解処理の進行状況を示すグラフ。FIG. 4 is a graph showing the progress of oxidative decomposition treatment of decontamination waste liquid in Example 1 of the present invention.
【図５】 本発明の実施例２において、クラッドにシミ
ュレートさせたＦｅ3Ｏ4の溶解除染の進行状況を示す、
図３と同様なグラフ。FIG. 5 shows the progress of dissolution decontamination of Fe 3 O 4 simulated in a clad in Example 2 of the present invention.
Graph similar to FIG.
【図６】 本発明の実施例２において、除染廃液の酸化
分解処理の進行状況を示す、図４と同様なグラフ。FIG. 6 is a graph similar to FIG. 4, showing the progress of oxidative decomposition treatment of decontamination waste liquid in Example 2 of the present invention.
【図７】 本発明の実施例３において、クラッドにシミ
ュレートさせたＦｅ3Ｏ4の溶解除染の進行状況を示す、
図３と同様なグラフ。FIG. 7 shows the progress of dissolution decontamination of Fe 3 O 4 simulated in a clad in Example 3 of the present invention,
Graph similar to FIG.
【図８】 本発明の実施例３において、除染廃液の酸化
分解の進行状況を示す、図４と同様なグラフ。FIG. 8 is a graph similar to FIG. 4, showing the progress of oxidative decomposition of the decontamination waste liquid in Example 3 of the present invention.
１ 除染液調製槽 ２ オゾン発生装置 ３ 泡発生槽 ４ 泡除染槽 ５ 除染対象試料 ６ 廃液処理槽 ７ 紫外線ランプ ８ オゾン吸着塔 ９ 廃液受槽 1 Decontamination liquid preparation tank 2 Ozone generator 3 Bubble generation tank 4 Bubble decontamination tank 5 Decontamination target sample 6 Waste liquid treatment tank 7 Ultraviolet lamp 8 Ozone adsorption tower 9 Waste liquid receiving tank
フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ２１Ｆ 9/16 ５６１ Ｇ２１Ｆ 9/16 ５６１Ｚ Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI Technical display location G21F 9/16 561 G21F 9/16 561Z
Claims (4)
続いてその除染廃液を処理する方法であって、除染剤お
よび起泡剤を溶解した水溶液中にオゾンを含有する空気
または酸素ガスを吹き込んで泡除染液を形成し、この泡
除染液を除染すべき機器・配管内に送り込んで除染を行
ない、除染を終って排出される泡除染廃液を廃液処理槽
へ受け入れ、残存するオゾンの存在下に紫外線を照射す
ることによって泡除染廃液中の有機化合物を酸化分解し
て、炭酸ガス、水および窒素ガスに無機化し、排ガスは
オゾン吸着装置を通して放出することからなる泡除染お
よび除染廃液処理の方法。1. A chemically decontaminated inner surface of a dirty device or pipe,
Then, a method for treating the decontamination waste liquid, which comprises blowing air or oxygen gas containing ozone into an aqueous solution in which a decontaminating agent and a foaming agent are dissolved to form a defoaming solution, and defoaming the foam. By sending the liquid into the equipment / pipe to be decontaminated for decontamination, receiving the defoaming waste liquid discharged after decontamination into the waste liquid treatment tank, and irradiating it with ultraviolet rays in the presence of residual ozone. A method of foam decontamination and decontamination waste liquid treatment, which comprises oxidatively decomposing organic compounds in a foam decontamination waste liquid to be mineralized into carbon dioxide gas, water and nitrogen gas, and discharging exhaust gas through an ozone adsorption device.
表される有機酸およびＥＤＴＡに代表されるキレート剤
からえらんだものを使用し、起泡剤として界面活性剤を
使用して実施する請求項１の方法。2. A decontaminating agent selected from oxalic acid, an organic acid represented by citric acid and a chelating agent represented by EDTA is used, and a surfactant is used as a foaming agent. The method of claim 1.
を使用し、温度４０〜８０℃で除染を行なう請求項１の
方法。3. The method according to claim 1, wherein decontamination is carried out at a temperature of 40 to 80 ° C. using a foam decontamination liquid consisting of bubbles having a diameter of 0.5 to 2 mm.
容したのち、固化処理工程へ送る請求項１の方法。4. The method according to claim 1, wherein the waste liquid containing the radioactive substance is concentrated and reduced in volume, and then sent to the solidification treatment step.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32335695A JPH09159798A (en) | 1995-12-12 | 1995-12-12 | Bubble decontamination and method for treating decontamination waste liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32335695A JPH09159798A (en) | 1995-12-12 | 1995-12-12 | Bubble decontamination and method for treating decontamination waste liquid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09159798A true JPH09159798A (en) | 1997-06-20 |
Family
ID=18153873
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32335695A Pending JPH09159798A (en) | 1995-12-12 | 1995-12-12 | Bubble decontamination and method for treating decontamination waste liquid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09159798A (en) |
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| US7713402B2 (en) | 2000-12-21 | 2010-05-11 | Kabushiki Kaisha Toshiba | Method for treating a chemical decontamination solution |
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1995
- 1995-12-12 JP JP32335695A patent/JPH09159798A/en active Pending
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| US7087120B1 (en) | 2002-11-21 | 2006-08-08 | Kabushiki Kaisha Toshiba | System and method for chemical decontamination of radioactive material |
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| KR101655061B1 (en) * | 2016-05-19 | 2016-09-06 | 주식회사 금화피에스시 | Method and Apparatus for Decontamination of Radioactive Metallic Wastes |
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