JPS5897698A - Method for cleaning nuclear fuel - Google Patents
Method for cleaning nuclear fuelInfo
- Publication number
- JPS5897698A JPS5897698A JP56197267A JP19726781A JPS5897698A JP S5897698 A JPS5897698 A JP S5897698A JP 56197267 A JP56197267 A JP 56197267A JP 19726781 A JP19726781 A JP 19726781A JP S5897698 A JPS5897698 A JP S5897698A
- Authority
- JP
- Japan
- Prior art keywords
- container
- fuel
- water
- pressure
- boiling
- 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.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Cleaning By Liquid Or Steam (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
発明の技術分野
本発明は、沸騰水形原子炉などの燃料を洗浄する際に適
用される原子炉燃料の洗浄方法に関する。DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for cleaning nuclear reactor fuel that is applied when cleaning fuel for boiling water nuclear reactors and the like.
背景技術およびその問題点
沸騰水形原子炉あるいは加圧水彩原子炉などのように水
を冷却材として用いる原子炉では、冷却材中に含まれる
金属不純物等が原子炉運転中に燃料集合体(以下単に燃
料と称す)などに付着して、いわゆるクラッドと呼ばれ
る金属腐食生成物となり強い放射線汚染源となる。この
ような付着汚染物は、燃料の冷却材通路を塞ぐ原因にな
るととも化、時々燃料から剥離し冷却材の流れにのって
原子炉の随所に運ばれ、原子炉内の各所に堆積して放射
線源になるなどの開亀を生じる。また、燃料に上記のよ
うな放射化された汚染物が付着していると、燃料の再処
理工程などにおいて放射線管理が困難になることが考え
られる。したがって、燃料に付着しているクラッド等を
除去することは重要である。BACKGROUND ART AND PROBLEMS In nuclear reactors that use water as a coolant, such as boiling water reactors or pressurized water reactors, metal impurities contained in the coolant may leak into fuel assemblies (hereinafter referred to as It adheres to materials such as fuel (simply referred to as fuel) and becomes a metal corrosion product called cladding, which becomes a strong source of radiation pollution. Such adhered contaminants not only cause blockage of the fuel coolant passages, but also sometimes separate from the fuel and are carried throughout the reactor by the flow of coolant, where they accumulate in various parts of the reactor. This can cause an open turtle, such as becoming a source of radiation. Furthermore, if the above-mentioned radioactive contaminants are attached to the fuel, radiation control may become difficult during the fuel reprocessing process. Therefore, it is important to remove crud and the like adhering to the fuel.
第1図は沸騰水形原子炉に用いられる燃料を示す。この
燃料aは、多数の燃料棒b・・・を束ねた燃料バンドル
Cの外側を、四角筒状のチャンネルボックスdで被った
ものであって、冷却材は下端部の入口ノズルeからチャ
ンネルボックスd内に入り、燃料棒b・・・の間を通っ
て上端部の出口fから出てゆくようになっている。した
がって、クラッドは主に上記燃料棒b・・・の表面に付
着する。Figure 1 shows the fuel used in boiling water reactors. This fuel a is obtained by covering the outside of a fuel bundle C made up of a large number of fuel rods b with a square cylindrical channel box d, and the coolant is supplied from an inlet nozzle e at the lower end of the channel box. d, passes between the fuel rods b... and exits from the outlet f at the upper end. Therefore, the crud mainly adheres to the surfaces of the fuel rods b...
従来、このクラッドを除去するには、チャンネルボック
スdを燃料バンドルCから取外したのち、たとえば燃料
プール中で水ジェツトを噴射したり、あるいはブラシ等
を擦り付けることによって除去する方法が採用されてい
る。しかしこれらの方法では、主に燃料バンドルCの外
周部付近しか洗浄することができないばかりか、チャン
ネルボックスdを燃料バンドルCから取外さなければ・
ならないため余計な手間が掛り、その分だけ作業時間が
長くなるという問題があった〇
発明の目的
本発明は上記事情にもとづきなされたものでその目的と
するところは、燃料の表面部分ばかりでなく燃料全体を
均等に洗浄して付着汚染物を除去できるとともに、チャ
ンネルボックス等のカバ一体を散外すことなくそのま才
内部を洗浄でき、作業が容易な原子炉燃料の洗浄方法を
提供することにある。Conventionally, this crud has been removed by removing the channel box d from the fuel bundle C and then, for example, spraying a water jet in a fuel pool or rubbing it with a brush or the like. However, with these methods, not only can only the outer periphery of the fuel bundle C be cleaned, but also the channel box d must be removed from the fuel bundle C.
Therefore, there was a problem that extra effort was required and the working time was increased accordingly.Objective of the Invention The present invention was made based on the above circumstances, and its purpose is to treat not only the surface part of the fuel but also the surface part of the fuel. To provide a method for cleaning nuclear fuel that is easy to work with and can evenly clean the entire fuel to remove adhering contaminants, and can also clean the inside of a channel box or the like without having to disassemble the cover itself. be.
発明の概要
すなわち本発明は、容器内に原子炉燃料を収容するとと
もにこの容器内に水を満たして密閉し、そののち上記容
器内の圧力をこの容器内の水が沸騰を生じる圧力鵞で減
圧し、この減圧沸騰により生じた気泡により原子炉燃料
の洗浄を行なうよう化した洗浄方法である。Summary of the Invention In other words, the present invention involves storing reactor fuel in a container, filling the container with water and sealing the container, and then reducing the pressure in the container using a pressure gauge that causes the water in the container to boil. However, this is a cleaning method in which the reactor fuel is cleaned using bubbles generated by this reduced pressure boiling.
すなわち、減圧沸騰は容器内の水のいたるところで生じ
るため、燃料の表面部分ばかりでなく燃料全体の隅々に
わたって気泡の発生・成長による衝撃力を与えることが
でき、これら気泡によって燃料に付着しているクラッド
等の付着汚染物を除去することができる。In other words, since vacuum boiling occurs everywhere in the water in the container, the impact force due to the generation and growth of bubbles can be applied not only to the surface of the fuel but also to every corner of the entire fuel, and these bubbles cause the water to adhere to the fuel. Adhering contaminants such as crud can be removed.
発明の実施例
以下本発明の一実施例について図面を参照して説明する
。第2図は本発明方法を実施するための装置を示すもの
であり、図中1は燃料aを収容する洗浄容器である。こ
の容器1は、その上端開口部を開閉自在な蓋2によって
密閉できるようになっている。3は上記蓋2を固定する
ための締付は具である。また、容器1の上端部には排出
口4が設けられていて、この排出口4に減圧弁5と送水
管6を介してフィルタrが接続されている。Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows an apparatus for carrying out the method of the present invention, and in the figure, 1 is a cleaning container containing fuel a. This container 1 is configured such that its upper end opening can be sealed with a lid 2 that can be opened and closed. 3 is a tightening tool for fixing the lid 2. Further, a discharge port 4 is provided at the upper end of the container 1, and a filter r is connected to the discharge port 4 via a pressure reducing valve 5 and a water pipe 6.
談た、上記容器lの底部には流通口8が設けられている
。この流通口8には空気弁yと流通管11を介して加圧
@11が接続されている。As mentioned above, a flow port 8 is provided at the bottom of the container 1. A pressurizer @11 is connected to this flow port 8 via an air valve y and a flow pipe 11.
この加圧器12は密閉容@秋をなしていて上記容器1に
連通し、かつ内部に水を貯留できるようになっていると
ともに、電熱ヒータIJによって内部の水を加熱できる
ように構成しである。This pressurizer 12 is a closed container, communicates with the container 1, and is configured to be able to store water therein, as well as to be able to heat the water inside with an electric heater IJ. .
なお、上記流通口8は燃料aの入口ノズルeに駅合し、
燃料鳳を支持する機能も兼ねている。Note that the above-mentioned flow port 8 is aligned with the inlet nozzle e of the fuel a,
It also has the function of supporting the fuel phoenix.
才た、燃料1の上端部は支持具14によって支持される
ようになっている。The upper end of the fuel 1 is supported by a support 14.
次に、上記実、施例装置を用いて燃料aを洗浄する方法
について説明する。まず、容器1の蓋2を開けて燃料a
を容器1内に収容する。次に蓋2を閉じて締付具3によ
って締め付は密閉するとともに、容器1と加圧器12、
流通管11などに水を満たす。そして減圧弁5を閉じ、
加圧器12のヒータ13に通電して容器1内の水を加熱
する。容器1内に閉じ込められた水が熱膨張を生じるこ
とから容器1内の圧力は高鵞り、水の沸点は100Cを
超える。すなわち、第3図番こ示したように1.5気圧
では約110.8c。Next, a method of cleaning fuel a using the above-mentioned embodiment apparatus will be explained. First, open the lid 2 of the container 1 and fill it with fuel a.
is stored in container 1. Next, the lid 2 is closed and the fastener 3 is used to seal the container 1 and the pressurizer 12.
Fill the flow pipe 11 with water. Then close the pressure reducing valve 5,
The heater 13 of the pressurizer 12 is energized to heat the water in the container 1. Since the water confined within the container 1 undergoes thermal expansion, the pressure inside the container 1 is high and the boiling point of water exceeds 100C. That is, as shown in Figure 3, at 1.5 atmospheres, it is approximately 110.8c.
2気圧では119.6tZ”、3気圧では132.9C
付近となる。119.6tZ" at 2 atm, 132.9C at 3 atm
It will be nearby.
次いで空気弁10を閉じ、減圧弁5を開弁させることに
よって、容器1内の圧力を解消させる。Next, the pressure inside the container 1 is released by closing the air valve 10 and opening the pressure reducing valve 5.
このとき容器1内の高温水は激しく減圧沸騰を生じるた
め、水中のあらゆる箇所から気泡が発生する。そして気
泡の発生・成長による衝撃力で燃料棒b・・・の表面か
ら剥離したクラッドは水中に放出され、沸騰により生じ
た水流にのって排出口4から送水管6に送られ、フィル
タ1に捕集される。At this time, the high-temperature water in the container 1 violently boils under reduced pressure, so that bubbles are generated from all parts of the water. The crud separated from the surface of the fuel rod b due to the impact force caused by the generation and growth of bubbles is discharged into the water, carried by the water flow generated by boiling, and sent from the discharge port 4 to the water pipe 6, where it is sent to the filter 1. is collected by.
すなわち上記方法によれば燃料バンドルCの表面部分ば
かりでなく、内部に配置されている燃料棒b・・・にも
気泡の発生・成長による衝撃力を作用させることができ
、燃料バンドルC全体を充分に洗浄できる。In other words, according to the above method, it is possible to apply an impact force due to the generation and growth of bubbles not only to the surface portion of the fuel bundle C but also to the fuel rods b arranged inside, and the entire fuel bundle C is Can be washed thoroughly.
そしてチャンネルボックスdを燃料バンドルCに取付け
た状態の才會洗浄できるから、チャンネルボックスdを
取外す余計な手間が省け、その分作業が簡略化する。Since the channel box d can be cleaned while attached to the fuel bundle C, the unnecessary effort of removing the channel box d is eliminated, and the work is simplified accordingly.
なお、沸騰の勢いを調節するには、減圧弁5の開度を調
整することによって容器1内の圧力降下の速さを増減さ
せればよい。あるいは、減圧沸騰させる前の圧力の高さ
を変えて減圧沸騰時の圧力降下の程度を調節することに
より、沸騰の勢いを調節するよう化してもよい。また、
容器1の圧力を高める手段として、たとえば加圧ポンプ
等の圧力発生装置を用いてもよい。In addition, in order to adjust the force of boiling, the speed of pressure drop within the container 1 may be increased or decreased by adjusting the opening degree of the pressure reducing valve 5. Alternatively, the intensity of boiling may be adjusted by changing the height of the pressure before boiling under reduced pressure and adjusting the degree of pressure drop during boiling under reduced pressure. Also,
As a means for increasing the pressure in the container 1, for example, a pressure generating device such as a pressure pump may be used.
なお上記実施例では容!Il内の水を、一旦高温高圧に
したのち減圧して沸騰させるようにしたが、本発明は例
えば容器1に真空ポンプなどの負圧発生機構を接続し、
その負圧によって容器1内を減圧して沸騰させるよう番
こしてもよい。In the above example, yong! The water in Il was once brought to high temperature and pressure, and then reduced in pressure and boiled. However, in the present invention, for example, a negative pressure generating mechanism such as a vacuum pump is connected to the container 1,
The negative pressure may be used to reduce the pressure inside the container 1 and bring it to a boil.
すなわち、第3図に示したように水は0.4気圧では7
5.4 C付近で沸騰し、0.2気圧では60C付近で
沸騰するから、沸騰水形原子炉の燃料プール水のように
たとえば設計温度が66C付近の場合には、容器1内に
プール水を入れて密閉し、容器内をたとえば0,2ない
し0.3気圧に減圧させることにより、燃料プール中に
おいて直接減圧沸騰させるようにしてもよい。このよう
にすれば、ヒータ等の加熱手段が不要となり、構造が簡
略化するとともに、設備も大型化することなくクラッド
を除去できる。In other words, as shown in Figure 3, water has a pressure of 7 atm at 0.4 atm.
It boils at around 5.4C, and at 0.2 atm it boils around 60C, so if the design temperature is around 66C, such as fuel pool water in a boiling water reactor, pool water in container 1 boils at around 60C. It is also possible to boil the fuel directly under reduced pressure in the fuel pool by filling the container with air, sealing it, and reducing the pressure inside the container to, for example, 0.2 to 0.3 atmospheres. In this way, a heating means such as a heater is not required, the structure is simplified, and the cladding can be removed without increasing the size of the equipment.
発明の効果
本発明は前記したように、密閉した容器内で減圧沸□騰
させ、その気泡の発生・成長による衝寒によって燃料に
付着しているクラッド等の付着汚染物を除去するように
したものである。したがって燃料の表面部分ばかりでな
く、燃料全体の隅々にわたって充分に洗浄することがで
き、除染効果が高い。しかもチャンネルボックスなどの
カバ一体を取外すことなくそのまま内部を洗浄できるか
ら、作業が簡略化し作業時間を短紬できるとともに、薬
品を使用することなく洗浄できるため燃料被覆を傷める
おそれがないなど、その効果は太きい。Effects of the Invention As described above, the present invention removes adhering contaminants such as crud adhering to the fuel by boiling it under reduced pressure in a closed container and using the cooling caused by the generation and growth of bubbles. It is something. Therefore, not only the surface portion of the fuel but also every corner of the entire fuel can be thoroughly cleaned, resulting in a high decontamination effect. What's more, the interior of the channel box can be cleaned without removing the cover itself, which simplifies the work and reduces work time.It also has the advantage that cleaning can be done without using chemicals, so there is no risk of damaging the fuel cladding. It's thick.
第1図は燃料集合体を一部切り欠いて示す斜視図、第2
図は本発明方法を実施するための装置を示す縦断面図、
第3図は水の圧力と沸騰温度の関係を示す特性図である
。
1・・・容器、12・・・加圧器、a・・・原子炉燃料
。
出願人代理人 弁理士 鈴 江 武 彦第1図
第2図Figure 1 is a partially cutaway perspective view of the fuel assembly;
The figure is a longitudinal sectional view showing an apparatus for carrying out the method of the present invention,
FIG. 3 is a characteristic diagram showing the relationship between water pressure and boiling temperature. 1... Container, 12... Pressurizer, a... Reactor fuel. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2
Claims (3)
容器内に水を満たして密閉し、そののち上記容器内の圧
力をこの容器内の水が沸騰を生じる圧力丈で減圧し、こ
の減圧沸騰により生じた気泡により上記原子炉燃料の洗
浄を行なうことを特徴とする原子炉燃料の洗浄方法。(1) Reactor fuel is stored in a container, and this container is filled with water and sealed, and then the pressure inside the container is reduced to a pressure level that causes the water in this container to boil, and this reduced pressure boiling is performed. A method for cleaning nuclear reactor fuel, characterized in that the reactor fuel is cleaned using bubbles generated by the above.
内の圧力を解消することにより減圧沸騰させることを特
徴とする特許請求の範囲第(1)項記載の原子炉燃料の
洗浄方法。(2) The method for cleaning nuclear reactor fuel according to claim (1), characterized in that the water in the container is once brought to a high pressure and then the pressure in the container is released to boil it under reduced pressure.
ることにより容器内の水を減圧沸騰させることを特徴と
する特許請求の範囲第(1)項記載の原子炉燃料の洗浄
方法。(3) The method for cleaning nuclear reactor fuel as set forth in claim (1), characterized in that water in the container is boiled under reduced pressure by reducing the pressure in the container using a negative pressure generation mechanism.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP56197267A JPS5897698A (en) | 1981-12-08 | 1981-12-08 | Method for cleaning nuclear fuel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP56197267A JPS5897698A (en) | 1981-12-08 | 1981-12-08 | Method for cleaning nuclear fuel |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5897698A true JPS5897698A (en) | 1983-06-10 |
JPS619600B2 JPS619600B2 (en) | 1986-03-25 |
Family
ID=16371625
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP56197267A Granted JPS5897698A (en) | 1981-12-08 | 1981-12-08 | Method for cleaning nuclear fuel |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5897698A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63271014A (en) * | 1987-04-30 | 1988-11-08 | Babcock Hitachi Kk | Burner cleaning method |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54120449A (en) * | 1978-03-10 | 1979-09-19 | Mitsubishi Heavy Ind Ltd | Method and apparatus for cleansing minute gaps |
JPS54147557A (en) * | 1978-05-12 | 1979-11-17 | Mitsubishi Heavy Ind Ltd | Narrow section cleaning method |
JPS5554500A (en) * | 1978-10-17 | 1980-04-21 | Nippon Atomic Ind Group Co | System for catching and storing decontaminated clad |
JPS55104799A (en) * | 1979-02-06 | 1980-08-11 | Denriyoku Chuo Kenkyusho | Method of removing depositted clad on surface of nuclear reactor fuel rod |
-
1981
- 1981-12-08 JP JP56197267A patent/JPS5897698A/en active Granted
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54120449A (en) * | 1978-03-10 | 1979-09-19 | Mitsubishi Heavy Ind Ltd | Method and apparatus for cleansing minute gaps |
JPS54147557A (en) * | 1978-05-12 | 1979-11-17 | Mitsubishi Heavy Ind Ltd | Narrow section cleaning method |
JPS5554500A (en) * | 1978-10-17 | 1980-04-21 | Nippon Atomic Ind Group Co | System for catching and storing decontaminated clad |
JPS55104799A (en) * | 1979-02-06 | 1980-08-11 | Denriyoku Chuo Kenkyusho | Method of removing depositted clad on surface of nuclear reactor fuel rod |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63271014A (en) * | 1987-04-30 | 1988-11-08 | Babcock Hitachi Kk | Burner cleaning method |
Also Published As
Publication number | Publication date |
---|---|
JPS619600B2 (en) | 1986-03-25 |
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