JPH01189600A - High temperature gas blow washing of spent fuel - Google Patents
High temperature gas blow washing of spent fuelInfo
- Publication number
- JPH01189600A JPH01189600A JP63013317A JP1331788A JPH01189600A JP H01189600 A JPH01189600 A JP H01189600A JP 63013317 A JP63013317 A JP 63013317A JP 1331788 A JP1331788 A JP 1331788A JP H01189600 A JPH01189600 A JP H01189600A
- Authority
- JP
- Japan
- Prior art keywords
- sodium
- spent fuel
- argon gas
- gas
- fuel
- 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
- 239000002915 spent fuel radioactive waste Substances 0.000 title claims abstract description 31
- 238000005406 washing Methods 0.000 title abstract description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims abstract description 40
- 239000011734 sodium Substances 0.000 claims abstract description 40
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 40
- 239000007789 gas Substances 0.000 claims abstract description 33
- 239000011261 inert gas Substances 0.000 claims abstract description 9
- 238000004140 cleaning Methods 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 15
- 239000002826 coolant Substances 0.000 claims description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 abstract description 28
- 229910052786 argon Inorganic materials 0.000 abstract description 14
- 239000000446 fuel Substances 0.000 abstract description 5
- 238000007664 blowing Methods 0.000 abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000012423 maintenance Methods 0.000 description 5
- 239000002901 radioactive waste Substances 0.000 description 4
- 206010073306 Exposure to radiation Diseases 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 239000010795 gaseous waste Substances 0.000 description 2
- 238000007738 vacuum evaporation Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- -1 for example Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、高速増殖炉のようにナトリウムを冷却材とす
る原子炉で使用した燃料を洗浄する方法に関し、更に詳
しくは、昇圧した高温の不活性ガスを使用済燃料にブロ
ーし、付着ナトリウムを吹き飛ばして除去する使用済燃
料の高温ガスブロー洗浄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 cleaning fuel used in a nuclear reactor that uses sodium as a coolant, such as a fast breeder reactor. The present invention relates to a high-temperature gas blow cleaning method for spent fuel, in which inert gas is blown onto the spent fuel to blow off and remove adhering sodium.
［従来の技術］
高速増殖炉のようにナトリウムを冷却材とする原子炉に
おいて、使用済燃料を再処理するまでの間、水プール等
で保管する場合には、先ず使用済燃料に付着している冷
却材ナトリウムを洗浄除去する必要がある。従来このよ
うな使用済燃料の洗浄は、脱塩水を使用し、それを循環
させて洗浄する所謂「脱塩水循環方式」が主流である。[Prior art] In a nuclear reactor that uses sodium as a coolant, such as a fast breeder reactor, when stored spent fuel in a water pool or the like until it is reprocessed, first the spent fuel is It is necessary to wash away the coolant sodium present. Conventionally, the mainstream method for cleaning such spent fuel has been the so-called "desalinated water circulation method," which uses demineralized water and circulates it for cleaning.
また一部海外では真空蒸発洗浄方式を採用しているとこ
ろもある。In some countries overseas, a vacuum evaporation cleaning method is also used.
［発明が解決しようとする課Ｈ］
従来の脱塩水循環方式では、燃料の構造上の特性（例え
ば燃料要素の間隔を均一に保持するランピング・ワイヤ
等による圧損）が洗浄性に大きな影響を及ぼし、所定の
レベルまで洗浄するにはそれ相当（約１〜２ｒＪ）の脱
塩水が必要となる。ところがこれらは全て放射性廃棄物
（廃液）となるため、それらを処理する設備が必要とな
る。また放射性腐蝕生成物により系統の線量が増大し廃
液処理作業やメンテナンス時の被曝源となる問題があっ
た。またナトリウムは水と激しく反応するため、設備上
取合という観点からナトリウム系と水系の隔離及び取合
を考慮する必要がある。このため回転・上下動機構等、
システムが複雑化しメンテナンス頻度も増大する。[Problem H to be solved by the invention] In the conventional demineralized water circulation system, the structural characteristics of the fuel (for example, pressure loss due to ramping wires that maintain uniform spacing between fuel elements) have a large effect on cleaning performance. , a corresponding amount (approximately 1 to 2 rJ) of demineralized water is required to clean to a predetermined level. However, all of this becomes radioactive waste (waste liquid), so equipment to process it is required. There was also the problem that radioactive corrosion products increased the radiation dose in the system and became a source of radiation exposure during wastewater treatment and maintenance. In addition, since sodium reacts violently with water, it is necessary to consider the separation and combination of sodium and water systems from the perspective of equipment integration. For this reason, rotation/vertical movement mechanisms, etc.
The system becomes more complex and the frequency of maintenance increases.
更に真空蒸発洗浄方式では、高温かつ高真空が必要不可
欠であるから必然的に設備が大型化する問題があるほか
、使用済燃料の残留熱の冷却に限界がある。Furthermore, the vacuum evaporation cleaning method requires high temperature and high vacuum, which inevitably increases the size of the equipment, and there is a limit to the ability to cool the residual heat of the spent fuel.
本発明の目的は、上記のような従来技術が有する課題を
解決し、放射性廃棄物が発生せず設備の簡素化を図るこ
とができ、メンテナンス頻度の合理化による建設・運転
コストの低減化、及び被曝の低減化を図ることができる
ような高温ガスブローによる使用済燃料の洗浄方法を提
供することにある。The purpose of the present invention is to solve the problems of the conventional technology as described above, to simplify equipment without generating radioactive waste, to reduce construction and operating costs by rationalizing maintenance frequency, and to It is an object of the present invention to provide a method for cleaning spent fuel using high-temperature gas blowing, which can reduce exposure to radiation.
［課題を解決するための手段］
上記目的を達成することができる本発明は、ナトリウム
を冷却材とする原子炉の使用済燃料に加熱廊圧した不活
性ガスをプローし、付着しているナトリウムを吹き飛ば
し除去するように構成した使用済燃料の高温ガスブロー
洗浄方法である。[Means for Solving the Problems] The present invention, which can achieve the above object, sprays heated inert gas into the spent fuel of a nuclear reactor using sodium as a coolant, and removes the adhering sodium. This is a high-temperature gas blow cleaning method for spent fuel configured to blow away and remove.
ここで高温の不活性ガスとしては、例えば２００℃程度
に加熱されたアルゴンガス等を使用する。Here, as the high temperature inert gas, for example, argon gas or the like heated to about 200° C. is used.
またガスブローによって吹き飛ばされ滴下したナトリウ
ムを集めて原子炉の１次系に戻すような構成が望ましい
。Further, it is desirable to have a configuration in which sodium dropped and blown off by gas blow is collected and returned to the primary system of the reactor.
［作用］
高温の不活性ガスを使用済燃料にプローすることによっ
て該使用済燃料に付着しているナトリウムは吹き飛ばさ
れ、また一部は蒸発する。[Operation] By blowing high-temperature inert gas onto the spent fuel, the sodium adhering to the spent fuel is blown off and some of it evaporates.
このようにして付着ナトリウムが除去され使用済燃料の
洗浄が行われる。In this way, the attached sodium is removed and the spent fuel is cleaned.
この洗浄は不活性雰囲気中での不活性ガスプローによる
ものであるから、滴下したナトリウムをそのまま１次系
に戻すことができる。これによって放射性廃棄物の発生
がなくなり、当然のことながら処理する必要もな（なる
。Since this cleaning is performed using an inert gas blower in an inert atmosphere, the dropped sodium can be directly returned to the primary system. This eliminates the generation of radioactive waste, and naturally there is no need to dispose of it.
［実施例１
第１図は本発明に係る使用済燃料の高温ガスプロー洗浄
方法を実施するのに好適な設備構成の一例を示している
。この洗浄設備は、使用済燃料１０を収納する洗浄槽１
２と、高温ガスを循環するためのガス系設備、及び各種
電気計装品等から構成される。[Example 1] FIG. 1 shows an example of an equipment configuration suitable for carrying out the method for cleaning spent fuel with a high-temperature gas blower according to the present invention. This cleaning equipment includes a cleaning tank 1 that stores spent fuel 10.
2, gas system equipment for circulating high-temperature gas, and various electrical instruments.
洗浄槽１２は使用済燃料１０を縦方向に挿入可能な竪型
構造になっており、内部に設けた保持部材１４等によっ
て使用済燃料１０を保持でき、上端開口はドアパルプ１
６等で密封可能な構造である。The cleaning tank 12 has a vertical structure into which the spent fuel 10 can be inserted vertically, and the spent fuel 10 can be held by a holding member 14 provided inside, and the upper end opening is a door pulp 1.
It has a structure that can be sealed at 6th grade.
高温ガスを循環するためのガス系設備は、エコノマイザ
２０、ベーパトラップ２２、冷却器２４、プロワ２６、
加熱器２８、その他配管や弁等から構成され、洗浄槽１
２を通る閉ループを構成できる。また、このガス系設備
にはアルゴンガス供給系３０が接続され、そこからアル
ゴンガスを導入できるようになっている。各種電気計装
品としては、閉ループの各所に設けられた圧力計や温度
計、流量計等である。Gas system equipment for circulating high-temperature gas includes an economizer 20, a vapor trap 22, a cooler 24, a blower 26,
Consists of a heater 28, other piping, valves, etc., and a cleaning tank 1
A closed loop passing through 2 can be constructed. Further, an argon gas supply system 30 is connected to this gas system equipment, from which argon gas can be introduced. Various electrical instruments include pressure gauges, thermometers, flow meters, etc. installed at various locations in the closed loop.
この実施例ではベーパトラップ２２、冷却器２４、ブロ
ア２６がそれぞれ２台ずつ並設されている。更に洗浄槽
１２の上部および前記ガス系設備の一部からは弁を介し
て気体廃棄物処理系３２へ配管で結ばれており、また洗
浄槽１２の底部と両ベーパトラップ２２からはそれぞれ
弁を備えた配管により１次ナトリウムドレーンタンク３
４へ接続されている。そして冷却器２４には冷却水系３
６の配管が接続されている。In this embodiment, two vapor traps 22, two coolers 24, and two blowers 26 are arranged in parallel. Further, the upper part of the cleaning tank 12 and a part of the gas system equipment are connected to the gaseous waste treatment system 32 via valves, and the bottom of the cleaning tank 12 and both vapor traps 22 are connected with valves, respectively. The primary sodium drain tank 3 is equipped with piping.
Connected to 4. The cooler 24 has a cooling water system 3.
6 pipes are connected.
このような設備による高温ガスプロー洗浄は次のように
行う、先ずアルゴンガス供給系３０から系統内へアルゴ
ンガスを供給した後、洗浄槽１２内に使用済燃料１０を
収納し、系統を隔離して閉ループを構成する。系統内の
アルゴンガスをプロワ２６で昇圧し、エコノマイザ２０
及び加熱器２８で約２００″Ｃ程度まで加熱した後、洗
浄槽１２へ供給する。そして使用済燃料１ｏにブローし
、その表面や内部、間隙部等に付着したナトリウムを吹
き飛ばす、吹き飛ばされたナトリウムの大部分は滴下し
、また一部分は蒸発する。洗浄槽１２から流出したナト
リウムベーパを含んだアルゴンガスはエコノマイザ２０
で冷却され、ベーパトラップ２２においてナトリウムベ
ーパが除去される。そして冷却器２４で更に降温された
後に、ブロワ２６に至り再び昇圧される。High-temperature gas blow cleaning using such equipment is carried out as follows. First, argon gas is supplied into the system from the argon gas supply system 30, and then the spent fuel 10 is stored in the cleaning tank 12, and the system is isolated. Configure a closed loop. The pressure of argon gas in the system is increased by the blower 26, and the economizer 20
The blown sodium is then heated to about 200"C in the heater 28 and then supplied to the cleaning tank 12.Then, the blown sodium is blown onto the spent fuel 1o to blow off the sodium attached to its surface, inside, gaps, etc. Most of the sodium vapor drips, and a portion evaporates.The argon gas containing sodium vapor that flows out from the cleaning tank 12 is
Sodium vapor is removed in a vapor trap 22. After the temperature is further lowered by the cooler 24, the temperature reaches the blower 26 and the pressure is increased again.
このような高温の不活性ガスの循環を数分もしくは数十
分行い、使用済燃料１０に付着しているナトリウムを除
去する。ガスブローによって使用済燃料１０から吹き飛
ばされたナトリウムは洗浄槽１２の下部に滴下堆積する
。この滴下ナトリウム３日は洗浄終了後に１次ナトリウ
ムドレーンタンク３４へ排出される。またベーパトラッ
プ２２にトラップされたナトリウムも同様に１次ナトリ
ウムドレーンタンク３４へと排出される。洗浄終了後、
系統内のアルゴンガスは気体廃棄物処理系３４へ送られ
、そこで処理されることになる。The circulation of such high-temperature inert gas is performed for several minutes or tens of minutes to remove the sodium adhering to the spent fuel 10. Sodium blown off from the spent fuel 10 by the gas blow drips and accumulates in the lower part of the cleaning tank 12. This dripping sodium for three days is discharged to the primary sodium drain tank 34 after washing is completed. Further, the sodium trapped in the vapor trap 22 is similarly discharged to the primary sodium drain tank 34. After cleaning,
The argon gas in the system will be sent to the gaseous waste treatment system 34 where it will be treated.
上記の実施例では装置の信鯨性並びにメンテナンス等の
観点からベーパトラップや冷却器、ブロワ等を２台並列
に接続しているが、原理的にはそれらは各１台であワて
もよい。In the above embodiment, two vapor traps, coolers, blowers, etc. are connected in parallel from the viewpoint of reliability and maintenance of the device, but in principle, each of them may be used alone. .
［発明の効果］
本発明は上記のように不活性雰囲気中で高温の不活性ガ
スを使用済燃料にブローし、付着しているナトリウムを
吹き飛ばし除去するように構成した使用済燃料の高温ガ
スブロー洗浄方法であるから、吹き飛ばされたナトリウ
ムをそのまま１次系に戻すことができ、そのため放射性
廃棄物が発生せず、勿論それを処理する必要もなくなる
。その結果、設備の単純化を図ることができるため設備
の建設コストを大幅に低減できると共に、メンテナンス
頻度等を削減でき、設備の運転コスト並びに被曝を大幅
に低減化できる効果がある。[Effects of the Invention] As described above, the present invention provides high-temperature gas blow cleaning for spent fuel, which is configured to blow away adhering sodium by blowing a high-temperature inert gas onto the spent fuel in an inert atmosphere. Because this method allows the blown sodium to be returned to the primary system as it is, no radioactive waste is generated and of course there is no need to dispose of it. As a result, since the equipment can be simplified, the construction cost of the equipment can be significantly reduced, and the frequency of maintenance can be reduced, which has the effect of significantly reducing the operating cost and radiation exposure of the equipment.
第１図は本発明方法を実施するのに好適な高温ガスブロ
ー洗浄設備の一例を示す説明図である。
１０・・・使用済燃料、１２・・・洗浄槽、２２・・・
ベーパトラップ、２４・・・冷却器、２６・・・ブロワ
、２８・・・加熱器、３０・・・アルゴンガス供給系、
３４・・・１次ナトリウムドレーンタンク。FIG. 1 is an explanatory diagram showing an example of high temperature gas blow cleaning equipment suitable for carrying out the method of the present invention. 10...Spent fuel, 12...Cleaning tank, 22...
Vapor trap, 24... Cooler, 26... Blower, 28... Heater, 30... Argon gas supply system,
34...Primary sodium drain tank.
Claims (1)
浄する方法において、加熱昇圧した不活性ガスを使用済
燃料にブローし、付着しているナトリウムを吹き飛ばし
除去することを特徴とする使用済燃料の高温ガスブロー
洗浄方法。 ２、吹き飛ばされ滴下したナトリウムを原子炉の１次系
に戻す請求項１記載の使用済燃料の高温ガスブロー洗浄
方法。[Claims] 1. A method for cleaning spent fuel in a nuclear reactor using sodium as a coolant, in which heated and pressurized inert gas is blown into the spent fuel to blow off and remove adhering sodium. A high-temperature gas blow cleaning method for spent fuel, characterized by: 2. The method for high-temperature gas blow cleaning of spent fuel according to claim 1, wherein the blown and dripped sodium is returned to the primary system of the nuclear reactor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63013317A JPH01189600A (en) | 1988-01-23 | 1988-01-23 | High temperature gas blow washing of spent fuel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63013317A JPH01189600A (en) | 1988-01-23 | 1988-01-23 | High temperature gas blow washing of spent fuel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01189600A true JPH01189600A (en) | 1989-07-28 |
Family
ID=11829795
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63013317A Pending JPH01189600A (en) | 1988-01-23 | 1988-01-23 | High temperature gas blow washing of spent fuel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01189600A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6718002B2 (en) * | 1997-05-21 | 2004-04-06 | Westinghouse Atom Ab | Method and device for removing radioactive deposits |
| CN102671878A (en) * | 2011-03-10 | 2012-09-19 | 中国原子能科学研究院 | Fast reactor spent component cleaning device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5546122A (en) * | 1978-09-29 | 1980-03-31 | Tokyo Shibaura Electric Co | Cleaning device for sodium equipment |
| JPS5786800A (en) * | 1980-11-20 | 1982-05-29 | Tokyo Shibaura Electric Co | Cleaning device for decontaminated sodium instruments |
| JPS6367597A (en) * | 1986-09-10 | 1988-03-26 | 財団法人 電力中央研究所 | Method of washing spent fuel aggregate |
| JPS63250598A (en) * | 1987-04-07 | 1988-10-18 | 川崎重工業株式会社 | Method of removing sodium of fast-reactor core component |
-
1988
- 1988-01-23 JP JP63013317A patent/JPH01189600A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5546122A (en) * | 1978-09-29 | 1980-03-31 | Tokyo Shibaura Electric Co | Cleaning device for sodium equipment |
| JPS5786800A (en) * | 1980-11-20 | 1982-05-29 | Tokyo Shibaura Electric Co | Cleaning device for decontaminated sodium instruments |
| JPS6367597A (en) * | 1986-09-10 | 1988-03-26 | 財団法人 電力中央研究所 | Method of washing spent fuel aggregate |
| JPS63250598A (en) * | 1987-04-07 | 1988-10-18 | 川崎重工業株式会社 | Method of removing sodium of fast-reactor core component |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6718002B2 (en) * | 1997-05-21 | 2004-04-06 | Westinghouse Atom Ab | Method and device for removing radioactive deposits |
| CN102671878A (en) * | 2011-03-10 | 2012-09-19 | 中国原子能科学研究院 | Fast reactor spent component cleaning device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH08189768A (en) | Vapor dryer, cleaning apparatus having the same assembled, and vapor drying method | |
| TWI666652B (en) | Apparatus for degassing a nuclear reactor coolant system | |
| EP1298677A2 (en) | A method of decontaminating by ozone and a device therefor | |
| US3437558A (en) | Nuclear reactor and refueling cell arrangement | |
| KR102043680B1 (en) | A separation device for tritium and a method for separating tritium | |
| US4963293A (en) | Flow control method for decontaminating radioactively contaminated nuclear steam generator | |
| JPH01189600A (en) | High temperature gas blow washing of spent fuel | |
| US6137018A (en) | Chemical refining method and reuse system for semiconductor device manufacturing | |
| US4109897A (en) | Salt reclamation system | |
| NL8601490A (en) | METHOD FOR SEPARATING RADIOACTIVE COMPONENTS FROM GASES OR VAPOR OF A NUCLEAR REACTOR. | |
| SE433144B (en) | DEVICE FOR STORING EXCELLENT NUCLEAR REACTOR FUEL ELEMENTS AND SETTING TO OPERATE THIS DEVICE | |
| JPH0767552B2 (en) | Cleaning equipment | |
| JPS6134116B2 (en) | ||
| JPS6263898A (en) | Method and device for processing chemical decontaminated waste liquor | |
| JPS5896300A (en) | Cleaning system for equipment contaminated with sodium | |
| US3041261A (en) | Art of cooling and moderating neutronic reactors | |
| JPH0358000A (en) | Washing spent fuel assembly and equipment therefor | |
| CN207468342U (en) | A kind of novel deaerator | |
| JP5912886B2 (en) | Chemical decontamination method | |
| EP0071020A2 (en) | Method for removing radioactive material from devices and apparatus therefor | |
| JPS6094102A (en) | Recirculating cover gas system | |
| JPS6367597A (en) | Method of washing spent fuel aggregate | |
| JPS6394199A (en) | Spent fuel treating facility for nuclear reactor facility | |
| JPS6367599A (en) | Method of washing spent fuel aggregate | |
| JPS6123520B2 (en) |