JPH055079B2 - - Google Patents
Info
- Publication number
- JPH055079B2 JPH055079B2 JP58231395A JP23139583A JPH055079B2 JP H055079 B2 JPH055079 B2 JP H055079B2 JP 58231395 A JP58231395 A JP 58231395A JP 23139583 A JP23139583 A JP 23139583A JP H055079 B2 JPH055079 B2 JP H055079B2
- Authority
- JP
- Japan
- Prior art keywords
- pipe
- decontamination
- oxide film
- iron oxide
- treated
- 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
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 38
- 238000005202 decontamination Methods 0.000 claims description 30
- 230000003588 decontaminative effect Effects 0.000 claims description 25
- 238000000034 method Methods 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 12
- 230000002285 radioactive effect Effects 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 8
- 239000008139 complexing agent Substances 0.000 claims description 6
- 238000004043 dyeing Methods 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 238000006722 reduction reaction Methods 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000004090 dissolution Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 3
- 238000009530 blood pressure measurement Methods 0.000 description 3
- 239000000498 cooling water Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000011010 flushing procedure Methods 0.000 description 2
- 239000003456 ion exchange resin Substances 0.000 description 2
- 229920003303 ion-exchange polymer Polymers 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- 239000003957 anion exchange resin Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000003729 cation exchange resin Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052595 hematite Inorganic materials 0.000 description 1
- 239000011019 hematite Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は通水される配管や機器の内側に付着、
堆積する酸化鉄皮膜の溶解法に関するもので、特
に原子力発電プラントの冷却水等の通る配管や機
器の内側に付着、堆積する放射能を有する酸化鉄
皮膜を溶解させるに適する方法に関する。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is directed to the invention,
The present invention relates to a method for dissolving deposited iron oxide film, and in particular to a method suitable for dissolving radioactive iron oxide film that adheres to and accumulates on the inside of piping and equipment through which cooling water passes through nuclear power plants.
原子力発電プラントの１次冷却水が接する配
管、機器等の内側には放射性の酸化鉄皮膜が形成
され、これがプラントの表面線量率を高める原因
になつており、これを除去することが望まれる。
殊に線量率が許容値を越える場合、更には原子力
発電所そのものの解体の場合には、プラントの配
管、機器系統の放射能を帯びた酸化鉄皮膜を除去
するいわゆる系統除染が必要になつてくる。この
系統除染は国内では実績がなく、僅かにカナダ、
アメリカの原子力発電所で実施されただけであ
る。この除染のむづかしさは配管、機器の母材で
ある炭素鋼又はステンレス鋼を溶解させないで表
面の放射性イオンを含む、２、３酸化鉄、４、３
酸化鉄の皮膜だけを溶解させなければならないこ
とにあり、これに適切な除染法を用いるとともに
除染剤の残留による母材への影響を考慮する必要
がある。除染法としては、酸化鉄皮膜の特性を考
慮して選定した酸、還元剤、錯化剤、インヒビタ
ーをブレンドした除染剤を使用する方法である。
この方法は酸化鉄比膜の溶解速度の点では優れて
いるが、母材をも溶解する危険性及び残留液によ
る腐食の心配が残る。他方、電気化学的除染法は
２つに大別できる。１つはカソード分極法、他の
１つの電解還元により還元液を作成し、電子を酸
化皮膜を付与する方法である。前者は酸化鉄皮膜
の電位を調整するために対極との間で分極し自身
に電子を付与する方法である。この方法では被溶
解皮膜に対向して対極を必要とするので大規模な
除染あるいは複雑な配管系統での除染がむづかし
いことがあげられる。後者の電子付与法は原理的
に酸化鉄皮膜のみの選択的溶解を可能とする優れ
た方法であるが、還元力を強化する電解槽とその
カソード材が限定され、除染性能の安定性、信頼
性に問題が残されている。
A radioactive iron oxide film is formed on the inside of piping, equipment, etc. that come in contact with the primary cooling water of a nuclear power plant, and this causes an increase in the surface dose rate of the plant, and it is desirable to remove this film.
In particular, when the dose rate exceeds the permissible value, or even when the nuclear power plant itself is dismantled, so-called system decontamination is required to remove radioactive iron oxide coatings from the plant's piping and equipment systems. It's coming. This system decontamination has no track record in Japan, and only in Canada,
It was only implemented at a nuclear power plant in the United States. The difficulty of this decontamination is that it does not dissolve the carbon steel or stainless steel that is the base material of piping and equipment, and the surface contains radioactive ions.
Only the iron oxide film needs to be dissolved, so it is necessary to use an appropriate decontamination method and consider the impact of residual decontamination agents on the base material. The decontamination method uses a decontamination agent that is a blend of acid, reducing agent, complexing agent, and inhibitor selected in consideration of the characteristics of the iron oxide film.
Although this method is superior in terms of the dissolution rate of the iron oxide film, there remains the risk of also dissolving the base material and the risk of corrosion due to residual liquid. On the other hand, electrochemical decontamination methods can be roughly divided into two types. One is a cathode polarization method, and the other is a method in which a reducing solution is created by electrolytic reduction and an oxide film is provided with electrons. The former is a method in which the iron oxide film is polarized with a counter electrode to provide electrons to itself in order to adjust the potential of the iron oxide film. Since this method requires a counter electrode facing the film to be dissolved, it is difficult to decontaminate large-scale decontamination or decontaminate complicated piping systems. The latter electron-imparting method is an excellent method that in principle enables selective dissolution of only the iron oxide film, but the electrolytic bath that strengthens the reducing power and its cathode materials are limited, and the stability of decontamination performance and Reliability remains an issue.
さらに機械的あるいは物理的方法として高圧水
でフラツシングする方法、超音波振動を加える方
法がある。これらは付着物の性状あるいは被付着
物の面積、距離等の幾何学的因子に除染効果が大
きく影響される。特にフラツシング法は比較的軟
質の付着物には効果がある。また超音波振動法は
超音波の振動到達距離に制限がある。 Furthermore, mechanical or physical methods include flushing with high pressure water and applying ultrasonic vibration. In these cases, the decontamination effect is greatly influenced by the properties of the deposits and geometric factors such as the area and distance of the deposits. The flushing method is particularly effective for relatively soft deposits. Furthermore, the ultrasonic vibration method has a limit on the distance that ultrasonic vibrations can reach.
本発明の目的は、これら既存あるいは開発中の
方法に比べて、配管、機器の系統除染を効率よく
行なわせることにある。
An object of the present invention is to perform systematic decontamination of piping and equipment more efficiently than these existing or under-development methods.
本発明の目的は、被処理材である配管の内表面
に付着堆積した放射能を帯びた鉄酸化物皮膜を除
染液と接触させて該酸化物皮膜を溶解除去する原
子力プラントの除染法において、前記被処理材で
ある配管内に配管内表面に対向する電極を設置し
て、該配管内に錯化剤を主体とした除染液を循環
させ、前記被処理材を陰極とするとともに前記対
向電極を陽極として両極の間で前記鉄酸化物皮膜
の電解還元を行ない、該電解還元した後又は該電
解還元と同時に前記被処理材である配管の外表面
から該配管に対して超音波振動をあたえることに
より達成される。
The object of the present invention is to provide a decontamination method for a nuclear power plant in which a radioactive iron oxide film deposited on the inner surface of piping, which is a material to be treated, is brought into contact with a decontamination solution to dissolve and remove the oxide film. In this method, an electrode is installed in the pipe, which is the material to be treated, opposite to the inner surface of the pipe, and a decontamination liquid mainly containing a complexing agent is circulated in the pipe, and the material to be treated is used as a cathode. The iron oxide film is electrolytically reduced between the two electrodes with the counter electrode as the anode, and after or simultaneously with the electrolytic reduction, ultrasonic waves are applied to the pipe from the outer surface of the pipe, which is the material to be treated. This is achieved by applying vibrations.
次に本発明について総括的に説明する。原子力
プラントの冷却水配管、機器に付着する酸化鉄皮
膜の成分はマグネタイト（Fe3O4）とヘマタイト
（α−Fe2O3）であり、この皮膜の中に放射性Co、
Mn等が含まれる。これらの酸化物と母材の炭素
鋼あるいはステンレス鋼の錯化剤（Y4-）と電子
（e-）が関与する溶解機構は次のようになる。 Next, the present invention will be comprehensively explained. The components of the iron oxide film that adheres to cooling water piping and equipment in nuclear power plants are magnetite (Fe 3 O 4 ) and hematite (α-Fe 2 O 3 ), and this film contains radioactive Co,
Contains Mn etc. The dissolution mechanism involving the complexing agent (Y 4- ) and electrons (e - ) of these oxides and the base material carbon steel or stainless steel is as follows.
Fe→Fe2+＋2e- ……(1)
Fe3O4＋8H＋3Y4-＋2e-
→3Fe：Y2-＋4H2O ……(2)
Fe2O3＋6H+＋2Y4-
＋2e-→2Fe：Y2-＋3H2O ……(3)
すなわち、金属鉄では(1)式が示すように電子を
放す酸化反応が進む。これに対してFe3O4、
Fe2O3では(2)、(3)式のように錯化剤の存在の下に
電子を取入れる還元反応が進行する。このように
酸化鉄では還元溶解反応を利用するために皮膜形
成金属を陰極すなわちカソード分極すればよいこ
とになる。ところでこのカソード分極を行なわせ
しめるには金属側を直接分極させるために対極と
の間で直流電流を流す方法をとるのが効果的であ
る。しかしながら皮膜あるいは付着物は金属材に
均一に付着していない場合が多い。特にステンレ
スの鋼の場合には酸洗浄等の前処理が施こされて
いることがあり、これによる表面の粒界腐食によ
るクレビス部が発生していることが予想され、こ
のクレビス部での付着物は先のカソード分極では
十分溶解させることが出来ない。ここに次の工程
として金属材に振動を与えることにある。これに
は金属材外面より周波数の高い超音波振動を加え
るとクレビス部を中心にして付着物を効果的に剥
離させることができ、除染効果を大巾に改善する
ことが可能となる。しかしながら金属外表面から
の超音波振動は局部的に加わるので、付着物の分
布に対応して振動を順次移動させていくことが必
要となる。 Fe→Fe 2+ +2e - ...(1) Fe 3 O 4 +8H+3Y 4- +2e - →3Fe:Y 2- +4H 2 O ......(2) Fe 2 O 3 +6H + +2Y 4- +2e - →2Fe:Y 2- +3H 2 O ...(3) In other words, in metallic iron, an oxidation reaction that releases electrons proceeds as shown in equation (1). On the other hand, Fe 3 O 4 ,
In Fe 2 O 3 , a reduction reaction that takes in electrons proceeds in the presence of a complexing agent as shown in equations (2) and (3). In this way, with iron oxide, in order to utilize the reduction and dissolution reaction, the film-forming metal may be cathodically polarized. By the way, in order to cause this cathode polarization to occur, it is effective to use a method in which a direct current is passed between the metal side and the counter electrode in order to directly polarize the metal side. However, the film or deposits often do not adhere uniformly to the metal material. In particular, in the case of stainless steel, pretreatment such as acid cleaning may be performed, and it is expected that crevices will occur due to intergranular corrosion on the surface. Kimono cannot be sufficiently dissolved by the previous cathodic polarization. The next step here is to apply vibration to the metal material. By applying ultrasonic vibrations with a higher frequency than the outer surface of the metal material, the deposits can be effectively peeled off centering on the clevis, making it possible to greatly improve the decontamination effect. However, since the ultrasonic vibrations from the outer surface of the metal are applied locally, it is necessary to sequentially move the vibrations in accordance with the distribution of deposits.
本発明の実施例を説明する。第１図は本発明の
方法を実施する酸化鉄皮膜除去のフローの一例を
概略的に示した図である。酸化鉄皮膜を除去した
いプラントの配管１に対して除染液を循環させる
系統２が接続されている。循環系統２の両端には
脱気兼用原水槽３、送液ポンプ４、イオン交換樹
脂槽５が配置されている。一方、配管の内部には
フレキシブル陽極６が設置され、配管を陰極７に
して外部からの直流電源８で電圧調整できる。さ
らに配管外面に超音波振動器９が付属している。
以上の配置、構造に対して、除染系統いついては
まず原水槽３に錯化剤を主成分とする除染液を加
温するとともに不活性ガスで溶液酸素を除去して
調整する。この除染液を被除染体の配管１を除染
して元の原水槽３に戻す。原水槽からの液中の溶
解金属イオンの分離にはカチオン交換樹脂塔５を
使う。常に溶存酸素を少なく、溶解成分を分離し
た除染液を使用する。電解還元除染には配管中の
陽極６と配管を陰極７にして先の除染液を電解を
行なわせしめる。陰極になつている配管付着物は
還元されて溶解が進行する。次に除染が進行して
いく過程あるいは終了時に配管外面から超音波振
動器９を順次移動させることにより残留付着物を
除去する。除染が完了するとアニオン交換樹脂５
で除染液を回収する。
Examples of the present invention will be described. FIG. 1 is a diagram schematically showing an example of the flow of removing an iron oxide film by carrying out the method of the present invention. A system 2 for circulating a decontamination liquid is connected to piping 1 of a plant whose iron oxide film is to be removed. At both ends of the circulation system 2, a deaeration and raw water tank 3, a liquid feed pump 4, and an ion exchange resin tank 5 are arranged. On the other hand, a flexible anode 6 is installed inside the pipe, and the voltage can be adjusted using a DC power supply 8 from outside by using the pipe as a cathode 7. Furthermore, an ultrasonic vibrator 9 is attached to the outer surface of the pipe.
Regarding the above arrangement and structure, the decontamination system is first adjusted by heating a decontamination solution containing a complexing agent as a main component in the raw water tank 3 and removing solution oxygen with an inert gas. This decontamination liquid is used to decontaminate the piping 1 of the object to be decontaminated and returned to the original raw water tank 3. A cation exchange resin column 5 is used to separate dissolved metal ions in the liquid from the raw water tank. Always use a decontamination solution with low dissolved oxygen and separated dissolved components. For electrolytic reduction decontamination, the anode 6 in the pipe and the cathode 7 are used to electrolyze the decontamination solution. The piping deposits that have become the cathode are reduced and dissolution progresses. Next, as decontamination progresses or at the end, residual deposits are removed by sequentially moving the ultrasonic vibrator 9 from the outer surface of the pipe. Once decontamination is complete, the anion exchange resin 5
Collect the decontamination solution.
次に本発明の特徴である移動式超音波振動器の
構造と操作について述べる。超音波振動器の配管
表面にとりつけた状態を第２図に示す。超音波振
動器９が配管１に設置されている。振動器は発振
器１０からの振動を伝える振動子１１から成つて
いる。これが配管に接続するには、リング１２と
接続端子１３が働く。配管径に合わせた固定がで
きるために振動子の反対側に２本の端子で長さを
調整して固定する。これを移動させるには接続端
子の車輪部を動かすようにする。これらの超音波
振動器の作動は振動器作動、移動速度等を自由に
調整できる機構を備えるとともに遠隔操作も可能
とする。 Next, the structure and operation of the mobile ultrasonic vibrator, which is a feature of the present invention, will be described. Figure 2 shows the ultrasonic vibrator attached to the surface of the pipe. An ultrasonic vibrator 9 is installed in the pipe 1. The vibrator consists of a vibrator 11 that transmits vibrations from an oscillator 10. The ring 12 and the connecting terminal 13 act to connect this to the pipe. In order to fix it according to the pipe diameter, adjust the length with two terminals on the opposite side of the vibrator and fix it. To move this, move the wheels of the connection terminal. The operation of these ultrasonic vibrators is equipped with a mechanism that allows the vibrator operation, moving speed, etc. to be freely adjusted, and remote control is also possible.
以下に本発明の有効性を示す実験例を説明す
る。まず超音波振動の管内面での強度変化に対す
る特性を実験で求めた結果を示す。試験装置を第
３図に示す。長さ90cmの２インチガス管１４厚さ
3.5mmの両端と管上部に音圧測定センサーが挿入
できる測定孔１５を多数設けている。この管に水
を入れ防振ゴム付の支持架台１６の上に設置して
いる。超音波振動の測定には発振器１７の振動子
１８を管に密着するようにして振動させ、水中の
各測定孔からのフエライト型音圧測定センサー１
９からの出力を電圧測定器２０で測定する。測定
は管中心部を振動子の左右での変化を求めた。結
果を第４図に示す。超音波振動器は100W出力、
28KHzであり、振動子は先端の面積0.8cm2のステ
ンレス棒で構成されている。管内には水を入れ各
測定孔での電圧を管の中心部から左右において測
定している。これより中心部で6Vを示し、左右
でほぼ対称に減衰している。このことは超音波振
動があたる部分が大きくこれより離れた場所では
減衰が大きくなることである。 Experimental examples demonstrating the effectiveness of the present invention will be described below. First, we will show the results of experiments to determine the characteristics of ultrasonic vibrations with respect to intensity changes on the inner surface of the tube. The test equipment is shown in Figure 3. 2 inch gas pipe 90 cm long 14 thick
A large number of measurement holes 15 into which sound pressure measurement sensors can be inserted are provided at both ends of the 3.5 mm tube and at the top of the tube. This tube is filled with water and placed on a support frame 16 equipped with anti-vibration rubber. To measure ultrasonic vibrations, the vibrator 18 of the oscillator 17 is vibrated in close contact with the tube, and the ferrite-type sound pressure measurement sensor 1 is emitted from each measurement hole in the water.
The output from 9 is measured with a voltage measuring device 20. Measurements were made to find changes in the center of the tube on the left and right sides of the vibrator. The results are shown in Figure 4. Ultrasonic vibrator has 100W output,
The frequency is 28KHz, and the vibrator consists of a stainless steel rod with a tip area of 0.8cm 2 . Water is placed inside the tube, and the voltage at each measurement hole is measured from the center of the tube to the left and right. It shows 6V at the center and attenuates almost symmetrically on the left and right sides. This means that the area hit by the ultrasonic vibrations is large, and the attenuation increases in areas farther away.
次に超音波振動により除染効果についての実験
結果を述べる。実験は放射能を有する鉄酸化物が
付着した配管を切断した試験片を使用した。試験
片はSUS304にFe3O4、α−Fe2O3が30μｍ程度付
着しており、付着物の中にCo−60を主体に0.8ｍ
Ｒ／ｈの放射性イオンが均一に分散している。こ
の試片をまず電解還元を行なつた。条件は
0.002M／EDTA・2NH4液、80℃で−1.0V
（VS.SCE）でカソード分極を5h行なつた。その
結果、放射能除去率50％がえられた。次に第５図
に示す超音波振動器の中に入れて放射能の除去特
性を求めた。超音波振動時間5minで90％前後の
放射能除去率がえられた。このように短時間で除
去率が向上する理由は付着物は溶解ではなく剥離
によるものである。なお試験片の設定位置での音
圧は電圧で5Vがえられている。以上の実験では
電解還元後に超音波振動を付与する方法をとつて
いるが、超音波振動を先に行なつても第６図の電
解還元しないで超音波振動を加えた結果が示すよ
うに鉄酸化物の剥離には有効でない。これは均一
な付着層には振動は有効でなく、電解還元による
凸凹部を有する付着層で振動が効果的に作用す
る。 Next, we will discuss the experimental results regarding the decontamination effect of ultrasonic vibration. The experiment used test pieces cut from piping to which radioactive iron oxide had adhered. The test piece has approximately 30 μm of Fe 3 O 4 and α-Fe 2 O 3 attached to SUS304, and 0.8 μm of Fe 3 O 4 and α-Fe 2 O 3 are attached to the SUS304.
Radioactive ions of R/h are uniformly dispersed. This specimen was first subjected to electrolytic reduction. condition is
0.002M/EDTA・2NH 4 liquid, -1.0V at 80℃
(VS.SCE) was used for cathodic polarization for 5 hours. As a result, a radioactivity removal rate of 50% was achieved. Next, the sample was placed in an ultrasonic vibrator shown in FIG. 5, and its radioactivity removal characteristics were determined. A radioactivity removal rate of around 90% was obtained with an ultrasonic vibration time of 5 minutes. The reason why the removal rate improves in such a short time is that the deposits are peeled off rather than dissolved. Note that the sound pressure at the set position of the test piece is 5V in terms of voltage. In the above experiments, a method was used in which ultrasonic vibrations were applied after electrolytic reduction, but even if ultrasonic vibrations were performed first, as shown in the results of applying ultrasonic vibrations without electrolytic reduction in Figure 6, Not effective for stripping oxides. This is because vibration is not effective on a uniform adhesion layer, but is effective on an adhesion layer that has uneven parts due to electrolytic reduction.
第１図は本発明の方法を実施する系統図、第２
第３図は超音波振動器の取付状態説明図、第４図
は音圧測定結果を示す線図、第５図は試験片によ
る実験状態を示す説明図、第６図は実験結果を示
す線図である。
１……配管、２……循環系統、５……イオン交
換樹脂槽、６……陽極、８……直流電源、９……
超音波振動器。
FIG. 1 is a system diagram for carrying out the method of the present invention;
Fig. 3 is an explanatory diagram of the installation state of the ultrasonic vibrator, Fig. 4 is a diagram showing the sound pressure measurement results, Fig. 5 is an explanatory diagram showing the experimental conditions using test pieces, and Fig. 6 is a diagram showing the experimental results. It is a diagram. 1...Piping, 2...Circulation system, 5...Ion exchange resin tank, 6...Anode, 8...DC power supply, 9...
Ultrasonic vibrator.
Claims (1)
放射能を帯びた鉄酸化物皮膜を除染液と接触させ
て該鉄酸化物皮膜を溶解除去する原子力プラント
の除染法において、 前記被処理材である配管内に配管内表面に対向
する電極を設置して、該配管内に錯化剤を主体と
した除染液を循環させ、 前記被処理材を陰極とするとともに前記対向電
極を陽極として両極の間で前記酸化物皮膜の電解
還元を行ない、 該電解還元した後又は該電解還元と同時に前記
被処理材である配管の外表面から該配管に対して
超音波振動を与えることを特徴とする原子力プラ
ントの除染法。[Claims] 1. Removal of a nuclear power plant in which a radioactive iron oxide film deposited on the inner surface of piping, which is a material to be treated, is brought into contact with a decontamination solution to dissolve and remove the iron oxide film. In the dyeing method, an electrode facing the inner surface of the pipe is installed in the pipe, which is the material to be treated, and a decontamination liquid mainly containing a complexing agent is circulated within the pipe, and the material to be treated is used as a cathode. At the same time, electrolytic reduction of the oxide film is performed between the two electrodes using the counter electrode as an anode, and after or simultaneously with the electrolytic reduction, ultraviolet rays are applied to the pipe from the outer surface of the pipe, which is the material to be treated. A nuclear plant decontamination method characterized by applying sonic vibrations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23139583A JPS60123800A (en) | 1983-12-09 | 1983-12-09 | Method of decontaminating nuclear plant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23139583A JPS60123800A (en) | 1983-12-09 | 1983-12-09 | Method of decontaminating nuclear plant |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60123800A JPS60123800A (en) | 1985-07-02 |
| JPH055079B2 true JPH055079B2 (en) | 1993-01-21 |
Family
ID=16922929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23139583A Granted JPS60123800A (en) | 1983-12-09 | 1983-12-09 | Method of decontaminating nuclear plant |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60123800A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5515009A (en) * | 1978-07-19 | 1980-02-01 | Hitachi Ltd | Method of removing radioactive clad |
| JPS5785980A (en) * | 1980-11-17 | 1982-05-28 | Hitachi Ltd | Method for removal of oxide on metallic surface |
| JPS5837078A (en) * | 1981-08-28 | 1983-03-04 | Sony Corp | Photochromic photosensitive composition |
| JPS58117500A (en) * | 1982-01-06 | 1983-07-13 | 株式会社日立製作所 | Method of decontaminating by electrolysis reduction |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6145171Y2 (en) * | 1981-01-17 | 1986-12-19 |
-
1983
- 1983-12-09 JP JP23139583A patent/JPS60123800A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5515009A (en) * | 1978-07-19 | 1980-02-01 | Hitachi Ltd | Method of removing radioactive clad |
| JPS5785980A (en) * | 1980-11-17 | 1982-05-28 | Hitachi Ltd | Method for removal of oxide on metallic surface |
| JPS5837078A (en) * | 1981-08-28 | 1983-03-04 | Sony Corp | Photochromic photosensitive composition |
| JPS58117500A (en) * | 1982-01-06 | 1983-07-13 | 株式会社日立製作所 | Method of decontaminating by electrolysis reduction |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60123800A (en) | 1985-07-02 |
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