JPS61194168A - Treatment for passivation of stainless steel pipe - Google Patents

Abstract

PURPOSE:To form a passivation film on the inside surface of a stainless steel pipe, etc., uniformly by subjecting the heated passivating fluid fed into a pipeline constituting body which is to be treated and consists of a stainless steel pipe, etc., to intermediate heating to prevent the temp. drop thereof. CONSTITUTION:The passivating fluid formed by adjusting the steam from a steam generator 6 and the pressurized air from an air compressor 7 to about 100:2 by the weight of air and water flowmeters 11, 12 and a control device 4 respectively is heated to about 310 deg.C by a heater 5 of a boiler 13 and is fed into the pipeline constituting body 1 which is to be treated and consists of the stainless steel pipe 2 and piping parts 3. The passivating fluid is further heated by an intermediate heater 8 in the mid-way of the body 1 and the temp. of the down flow in proximity thereto is measured by a thermometer 14. The intermediate heating quantity is adjusted by the control device 4 in accordance with the measured value, by which the temp. in the longitudinal direction of the pipeline is made uniform. If a narrow part N exists in said body, a dummy pipe 15 is preferably provided by branching the pipeline to make uniform the Raynolds number in each part of the body 1 and to decrease the uneven flow rate of the passivating fluid.

Description

【発明の詳細な説明】 「産業上の利用分野」 本発明はステンレス鋼管の不働態化処理方法に係り、特
に高温状態の蒸気及び空気の混合流体によって、ステン
レス鋼管の内面に不働態化被膜を形成して安定化を図る
処理方法に関するものである。Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for passivating stainless steel pipes, and in particular to forming a passivation film on the inner surface of stainless steel pipes using a mixed fluid of steam and air at a high temperature. The present invention relates to a treatment method for forming and stabilizing the material.

「従来の技術とその問題点」 一般に、原子力発電プラント、化学プラント等には、オ
ーステナイト系ステンレス鋼管が使用されているが、沸
騰水型原子炉の場合等であると、核加熱によって放射化
された”Ｃｏｔ”Ｍｎ＋”’Ｃｓ及びその酸化物等が、
原子炉の一次冷却系の配管等に次第に付着し、管路の放
射線量を上昇させてしまう可能性がある。このとき、＠
０Ｃｏ等の放射性物質は、ステンレス鋼管の内面に放射
化金属に化学的な親和性を持たないような処理を予め施
しておくとともに、内面を円滑にしておくことにより、
付着量を減少させることができるものと考えられる。ま
た、本発明者等の研究によれば、ステンレス鋼管の内面
には、常温状態で生じた不働態化被膜（Ｃｒ−Ｎｉ等の
酸化被膜）が形成されて比較的安定な状態となっている
が、高温加湿空気をステンレス鋼管に積極的に接触させ
る等の処理を施すことによって、放射性物質の付着の少
ない良質の不働態化被膜を形成することができる可能性
を有している。"Conventional technology and its problems" Generally, austenitic stainless steel pipes are used in nuclear power plants, chemical plants, etc., but in boiling water reactors, etc., they become radioactive due to nuclear heating. “Cot”Mn+”’Cs and its oxides, etc.
There is a possibility that it will gradually adhere to the pipes of the reactor's primary cooling system, increasing the radiation dose in the pipes. At this time,@
Radioactive substances such as 0Co can be treated by pre-treating the inner surface of the stainless steel pipe so that it has no chemical affinity for radioactive metals, and by making the inner surface smooth.
It is thought that the amount of adhesion can be reduced. Furthermore, according to research by the present inventors, a passivation film (an oxide film such as Cr-Ni) formed at room temperature is formed on the inner surface of a stainless steel pipe, resulting in a relatively stable state. However, by performing treatments such as actively bringing high-temperature humidified air into contact with stainless steel pipes, it is possible to form a high-quality passivation film with less adhesion of radioactive substances.

この場合に使用される高温加湿空気は、例えば、温度３
００℃で空気と水との重量比が１００：２であるものを
利用するが、被処理ステンレス鋼管の一部に狭あい部が
あるとその付近で流速が高まり、他の部分との間で、処
理条件のむらを生じる可能性があり、また、管路が長い
場合でも、その途中で前記高温加湿空気の温度が低下し
て処理条件のむらを生じ易く、正確な調整を行なうこと
が困難となる等の問題点が生じる。The high temperature humidified air used in this case is, for example,
The weight ratio of air and water at 00°C is 100:2. However, if there is a narrow part of the stainless steel pipe to be treated, the flow velocity will increase near that part, and the flow rate will increase between it and other parts. In addition, even if the pipe line is long, the temperature of the high-temperature humidified air decreases along the way, which tends to cause unevenness in the processing conditions, making it difficult to make accurate adjustments. Problems such as this arise.

「発明の目的とその達成手段」 本発明は、このような問題点を解決するために、ステン
レス鋼管及び配管部品等からなる被処理管路構成体に、
加熱された不働態化流体を送り込み、該被処理管路構成
体の途中で不働態化流体を中間加熱して、該加熱箇所に
近接する下流の温度を計測し、該温度データにより中間
加熱量を調整することにより、管路の長さ方向の温度を
均一化し、さらに、前記被処理管路構成体に狭あい部が
存在しているとき、その上流で不働態化流体を分流し、
該分流量の調整により、被処理管路構成体の各部におけ
るレイノルズ数をほぼ均一として、不働態化流体の流速
むらを少なくするものである。"Objects of the Invention and Means for Achieving the Same" In order to solve these problems, the present invention provides a pipeline structure to be treated consisting of stainless steel pipes, piping parts, etc.
The heated passivation fluid is sent in, the passivation fluid is intermediately heated in the middle of the pipeline structure to be treated, the temperature downstream near the heating point is measured, and the amount of intermediate heating is determined based on the temperature data. by adjusting the temperature in the length direction of the pipe line, and further, when a narrow part exists in the pipe line structure to be treated, dividing the passivating fluid upstream of the narrow part,
By adjusting the divided flow rate, the Reynolds number in each part of the pipeline structure to be treated is made substantially uniform, thereby reducing unevenness in the flow velocity of the passivation fluid.

「実施例」 以下、本発明のステンレス鋼管の不働態化処理方法の一
実施例を図面に基づいて説明する。"Example" Hereinafter, an example of the passivation treatment method for stainless steel pipes of the present invention will be described based on the drawings.

第１図によりまず不働態化処理に使用する主要装置等を
説明すると、符号ｌは不働態化処理を施す被処理管路構
成体、符号２及び３は被処理管路構成体ｌを構成するス
テンレス鋼管及び配管部品、符号４は制御装置、符号５
は主加熱器、符号６は蒸気発生器、符号７はエア・コン
プレッサ、符号８は被処理管路構成体Ｉの肩囲に設けら
れる誘導加熱コイル等の中間加熱器である。First, the main equipment used in the passivation process will be explained with reference to FIG. 1. Reference numerals 1 and 3 refer to the pipeline structure to be treated, l, which is to be subjected to the passivation process. Stainless steel pipes and piping parts, code 4 is control device, code 5
6 is a main heater, 6 is a steam generator, 7 is an air compressor, and 8 is an intermediate heater such as an induction heating coil provided around the shoulder of the pipeline structure I to be treated.

これらの装置等において、まず、蒸気発生器６からのス
トレーナ９を経由する蒸気（水蒸気）と、エア・コンプ
レッサ７からのフィルタ１０を経由する加圧空気とを混
合するとともに、これらの量を流量計１１・１２により
計測して、データを破線で示すように制御装置４に出力
し、前述した重量比となるように管理する。In these devices, first, steam (steam) from the steam generator 6 passing through the strainer 9 and pressurized air passing through the filter 10 from the air compressor 7 are mixed, and the amounts of these are controlled by the flow rate. A total of 11 and 12 are measured, and the data is output to the control device 4 as shown by the broken line, and managed so that the weight ratio described above is achieved.

次いで、混合により生じた加湿空気（以下、不働態化流
体という　）を主加熱器５のボイラ１３により、例えば
３１０℃に加熱し、該加熱された不働態化流体を被処理
管路構成体ｌのステンレス鋼管２に送り込み、該ステン
レス鋼管２の表面温度を温度計１４により検出して、そ
のデータを制御装置４に出力し、前記ボイラ１３による
加熱温度の調整を行なう。Next, the humidified air (hereinafter referred to as passivation fluid) generated by the mixing is heated to, for example, 310° C. by the boiler 13 of the main heater 5, and the heated passivation fluid is transferred to the pipeline structure to be treated l. The temperature of the surface of the stainless steel tube 2 is detected by a thermometer 14, and the data is output to the control device 4 to adjust the heating temperature by the boiler 13.

また、被処理管路構成体ｌの途中の中間加熱器８を作１
ｌｌＩ六什て一披机伸管蕗堪虚汰１の山間の一部を加熱
する等の方法で、その内部の不働態化流体の温度を前述
の３１０℃に維持するようにするとともに、中間加熱箇
所の下流側の近接位置に取り付けられている温度計１４
により、被処理管路構成体ｌの表面温度を検出して、そ
のデータを第１図の実線で示すように制御装置４に出力
し、その直前の中間加熱器８による温度管理を行なう。In addition, an intermediate heater 8 in the middle of the pipeline structure 1 to be treated is made.
llI6 The temperature of the passivation fluid inside is maintained at the above-mentioned 310°C by heating a part of the mountain between the pipes and pipes 1, and the intermediate temperature is A thermometer 14 attached to a position adjacent to the downstream side of the heating point
As a result, the surface temperature of the pipeline structure 1 to be treated is detected, and the data is outputted to the control device 4 as shown by the solid line in FIG. 1, and the temperature is controlled by the intermediate heater 8 just before that.

被処理管路構成体ｌが長い場合、及び多数のステンレス
鋼管２を直列接続している場合でも、中間加熱を繰り返
し行なうことにより、管路の長さ方向の温度を均一化す
ることができる。Even when the pipeline structure 1 to be treated is long, or even when a large number of stainless steel pipes 2 are connected in series, the temperature in the length direction of the pipeline can be made uniform by repeatedly performing intermediate heating.

また、前記被処理管路構成体ｌの一部に、細い部分があ
るような場合、即ち、狭あい部Ｎが存在しているときは
、その上流の直前の位置における配管部品３に、ステン
レス鋼管２とダミーバイブ１５とを並列に接続して、高
温不働態化流体を分流し、該分流量の調整により、被処
理管路構成体ｌの各部と狭あい部Ｎとのレイノルズ数を
ほぼ均一として、不働態化流体の流速むらを少なくする
ものである。このレイノルズ数は、３１０’Ｃに換算し
て、２００００（±５０％）程度に設定する。そして、
分流された不働態化流体は、再度合流させられて、次の
被処理管路構成体ｌに送り込まれるか、あるいは大気中
に放出する等により廃棄される。In addition, if there is a narrow part in a part of the pipe structure 1 to be treated, that is, if a narrow part N exists, the piping part 3 at the position immediately before the upstream part is made of stainless steel. The steel pipe 2 and the dummy vibe 15 are connected in parallel, and the high-temperature passivation fluid is divided into parts, and by adjusting the divided flow rate, the Reynolds number of each part of the pipeline structure L to be treated and the narrow part N can be approximately adjusted. As the passivating fluid is uniform, the flow velocity unevenness of the passivating fluid is reduced. This Reynolds number is set to about 20000 (±50%) in terms of 310'C. and,
The divided passivation fluids are combined again and sent to the next pipeline structure 1 to be treated, or are disposed of by being discharged into the atmosphere.

このような処理を例えば１５０〜３６０時間実施すると
、被処理管路構成体！の各部におけるステンレス鋼管２
及び配管部品３の内面等に、高温状態の不働態化流体が
接触することに基づいて、均一で非常に薄いＣｒ−Ｎｉ
等の不働態化被膜の形成が促進されるとともに、これら
が蒸気の存在により良質の不働態化被膜とすることがで
きる。第２図は、無処理のままの被処理管路構成体１（
破線Ｘ）と、第１図例における処理を施した被処理管路
構成体（実線Ｙ）とに、放射性金属粒体が付着する現象
の実験例を示しており、被処理管路構成体ｌの内面に、
積極的な不働態化処理を施すことによって、放射線レベ
ルを２０〜５０％程度に軽減できるとともに、この状態
で付着量の増加が減少することを示唆するものである。When such treatment is carried out for, for example, 150 to 360 hours, the pipeline structure to be treated! Stainless steel pipe 2 in each part of
Based on the fact that the high-temperature passivation fluid comes into contact with the inner surface of the piping component 3, uniform and very thin Cr-Ni
The formation of passivated films such as these is promoted, and the presence of steam makes it possible to form high-quality passivated films. FIG. 2 shows the untreated pipeline structure 1 (
This shows an experimental example of the phenomenon in which radioactive metal particles adhere to the pipe line structure to be treated (solid line Y) that has been treated in the example shown in FIG. On the inside of
This suggests that by performing active passivation treatment, the radiation level can be reduced to about 20 to 50%, and that the increase in adhesion amount can be reduced in this state.

なお、第１図例では、管路を単純化した被処理管路構成
体を示しているが、レイノルズ数を合わせ得る範囲で、
直列あるいは並列接続とすることを行ない得るとともに
、並列数を３以上とすることら可能であり、分流した不
働態化流体を再び合流するようにすることも任意である
。In addition, although the example in FIG. 1 shows the treated pipe line structure with a simplified pipe line, as long as the Reynolds number can be matched,
They can be connected in series or in parallel, and the number of parallel connections can be three or more, and it is also optional to connect the divided passivation fluids together again.

「発明の効果」 以上説明したように、本発明によれば、加熱された不働
態化流体を途中で中間加熱するとともに、中間加熱箇所
の下流位置に近接した温度を検出して中間加熱量を調整
するようにしているため、温度変化の補正を速やかに行
なうことが可能となり、被処理管路構成体の長さ方向の
温度むらを少なくし、不働態化被膜の均一性を図ること
ができる。"Effects of the Invention" As explained above, according to the present invention, the heated passivation fluid is intermediately heated in the middle, and the temperature near the downstream position of the intermediate heating point is detected to calculate the intermediate heating amount. Since it is adjusted, it is possible to quickly correct temperature changes, reduce temperature unevenness in the length direction of the pipeline structure to be treated, and achieve uniformity of the passivation film. .

また、管路におけるレイノルズ数を合わけることにより
、不働態化流体の流量、流速をほぼ一致させることが可
能で、処理条件の均一化により安定した不働態化処理を
効率良く形成することができる等の効果を奏するもので
ある。In addition, by matching the Reynolds numbers in the pipes, it is possible to almost match the flow rate and flow velocity of the passivation fluid, and by making the processing conditions uniform, it is possible to efficiently form a stable passivation treatment. It has the following effects.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明のステンレス鋼管の不働態処理方法の一
実施例に適用される配管系統図、第２図は処理条件と放
射線レベルとの関係曲線図である。 ■・・・・・・被処理管路構成体、２・・・・・・ステ
ンレス鋼管、３・・・・・・配管部品、４・・・・・・
制御装置、５・・・・・・主加熱器、６・・・・・・蒸
気発生器、７・・・・・・エア・コンプレッサ、８・・
・・・・中間加熱器、１３・・・・・・ボイラ、１４・
・・・・・温度計、Ｎ・・・・・・狭あい部。FIG. 1 is a piping system diagram applied to an embodiment of the method for passive treatment of stainless steel pipes of the present invention, and FIG. 2 is a diagram showing a relationship curve between treatment conditions and radiation levels. ■... Pipe line structure to be treated, 2... Stainless steel pipe, 3... Piping parts, 4...
Control device, 5... Main heater, 6... Steam generator, 7... Air compressor, 8...
...Intermediate heater, 13...Boiler, 14.
...Thermometer, N ... Narrow space.

Claims (2)

【特許請求の範囲】[Claims] （１）ステンレス鋼管及び配管部品等からなる被処理管
路構成体に、加熱された不働態化流体を送り込み、該被
処理管路構成体の途中で不働態化流体を中間加熱して、
該加熱箇所に近接する下流の温度を計測し、該温度デー
タにより中間加熱量を調整することを特徴とするステン
レス鋼管の不働態化処理方法。(1) A heated passivation fluid is fed into a pipeline structure to be treated consisting of stainless steel pipes, piping parts, etc., and the passivation fluid is intermediately heated in the middle of the pipeline structure to be treated,
A method for passivating stainless steel pipes, the method comprising measuring the temperature downstream of the heating point and adjusting the amount of intermediate heating based on the temperature data. （２）ステンレス鋼管及び配管部品等からなる被処理管
路構成体に、加熱された不働態化流体を送り込み、該被
処理管路構成体の途中で不働態化流体を中間加熱して、
該加熱箇所に近接する下流の温度を計測し、該温度デー
タにより中間加熱量を調整するとともに、前記被処理管
路構成体の狭あい部の上流で不働態化流体を分流し、被
処理管路構成体の各部におけるレイノルズ数をほぼ均一
とすることを特徴とするステンレス鋼管の不働態化処理
方法。(2) feeding the heated passivation fluid into the pipeline structure to be treated, such as stainless steel pipes and piping components, and intermediately heating the passivation fluid in the middle of the pipeline structure to be treated;
The downstream temperature close to the heating point is measured, and the intermediate heating amount is adjusted based on the temperature data, and the passivating fluid is diverted upstream of the narrow part of the pipeline structure to be treated, and the A method for passivating a stainless steel pipe, characterized by making the Reynolds number substantially uniform in each part of a passage structure.