JPH047840B2 - - Google Patents
Info
- Publication number
- JPH047840B2 JPH047840B2 JP59013060A JP1306084A JPH047840B2 JP H047840 B2 JPH047840 B2 JP H047840B2 JP 59013060 A JP59013060 A JP 59013060A JP 1306084 A JP1306084 A JP 1306084A JP H047840 B2 JPH047840 B2 JP H047840B2
- Authority
- JP
- Japan
- Prior art keywords
- shield
- shielding layer
- cooling
- lead
- pipe
- 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
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
- Y02E30/10—Nuclear fusion reactors
Landscapes
- Particle Accelerators (AREA)
- Processing Of Color Television Signals (AREA)
- Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
- Medicines Containing Material From Animals Or Micro-Organisms (AREA)
Description
【発明の詳細な説明】
本発明は、核融合炉の遮蔽体の冷却配管の貫通
部における炉停止後の崩壊ガンマ線ストリーミン
グ防止機構に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a decay gamma ray streaming prevention mechanism after reactor shutdown in a cooling piping penetration portion of a shield of a nuclear fusion reactor.
核融合炉、例えばトロイダル磁場コイルによつ
て作られるトロイダル磁場と円周方向に沿つて作
つたプラズマ中に電流を流して、この電流によつ
て発生するポロイダル磁場の力によつてプラズマ
をトーラス状に閉じこめて核融合反応を起させる
トカマク型核融合炉では、第１図に示すごとく、
ドーナツ状のプラズマ１を囲むように内側ブラン
ケツト２、外側ブランケツト２′，内側遮蔽体３，
外側遮蔽体３′，トロイダル磁場コイル４，ポロ
イダル磁場コイル５等から構成されている。その
他、高いエネルギーを持つた電気的に中性の粒子
をプラズマに入射して、そのエネルギーをプラズ
マに与えることによつてプラズマの温度を上げる
役目をはたす中性粒子入射加熱装置、プラズマ中
に混入してくる放電ガス以外のイオンや原子，分
子等の不純物を系外に排出する排気装置７が設置
されている。トカマク型核融合炉は概ね上記のよ
うに構成されているが、このうち主要な構成機器
である遮蔽体３，３′はプラズマ周囲に位置して
おり中性子，ガンマ線等の放射線を遮蔽する重要
な機能を有している。炉の供用期間中、検査等の
停止時には外側遮蔽体３′まで人間が接近するが、
その外側遮蔽体３′には内側，外側ブランケツト
２，２′やダイバータ６等の多数の冷却配管が貫
通（図示省略）しているので、その配管の貫通部
から中性子またはガンマ線が外へすりぬけてゆく
現象、いわゆるストリーミングが起るので、その
対策が必要であつた。 In a fusion reactor, for example, a current is passed through a toroidal magnetic field created by a toroidal magnetic field coil and a plasma created along the circumference, and the plasma is shaped into a toroid by the force of the poloidal magnetic field generated by this current. In a tokamak-type fusion reactor, in which nuclear fusion reactions occur by confining the reactor to
An inner blanket 2, an outer blanket 2', an inner shield 3,
It is composed of an outer shield 3', a toroidal magnetic field coil 4, a poloidal magnetic field coil 5, etc. In addition, there is a neutral particle injection heating device that increases the temperature of the plasma by injecting electrically neutral particles with high energy into the plasma and giving that energy to the plasma. An exhaust device 7 is installed to exhaust impurities such as ions, atoms, and molecules other than the discharge gas coming out of the system. A tokamak-type fusion reactor is generally configured as described above, but the main components, the shields 3 and 3', are located around the plasma and are important for shielding radiation such as neutrons and gamma rays. It has a function. During the service life of the reactor, people will approach the outer shield 3' when inspections, etc. are stopped.
Since many cooling pipes (not shown) such as the inner and outer blankets 2, 2' and the diverter 6 pass through the outer shield 3', neutrons or gamma rays may slip outside through the pipe penetrations. Since the phenomenon of so-called streaming is occurring, it was necessary to take countermeasures against it.
従来、遮蔽体は第１図に示すごとく、内外側ブ
ランケツト２，２′の外側に配置されており、核
融合炉から出る放射線を遮蔽する役割を果してい
る。プラズマ内の核融合反応により発生した高エ
ネルギー中性子は、ブランケツト２，２′内で保
持しているエネルギーを熱エネルギーに変換して
放出し、中性子束密度自身はかなり減衰して遮蔽
体３，３′に入射して来て、そこでその殆んどが
吸収されるが、一部は遮蔽体３，３′の構成材料
であるステレン鋼に含有している核種との核反応
により、放射性核種を生成（放射化）する。例え
ば58Ni（ｎ，ｐ）58Co，56Fe（ｎ，ｐ）54Nn反応等に
より生成した放射性核種は炉停止後も放射性崩壊
によりガンマ線を放出し続け、遮蔽体３′に接近
する作業員に放射性被曝を与える原因となる。そ
のためその対策として第２図に示すように、殆ん
ど放射化せず、且つガンマ線に対する良好な遮蔽
性能を示す鉛１０を遮蔽体３′外側に張設してガ
ンマ線１４を吸収し、作業員に対する被曝線量を
低減化していた。しかしながら第３図に示すよう
に、冷却配管１５の貫通部において、配管１５の
周囲の放射化した物質から発するガンマ線１４
が、ガンマ線１４に対する遮蔽能力の弱い冷却材
１６の中を通り抜けてくる、いわゆるストリーミ
ングが起り、遮蔽体外側における作業員の被曝線
量を増大する原因となつており、その対策が急が
れていた。 Conventionally, as shown in FIG. 1, a shielding body has been placed outside the inner and outer blankets 2, 2', and has the role of shielding radiation emitted from a fusion reactor. High-energy neutrons generated by the nuclear fusion reaction in the plasma convert the energy held within the blankets 2, 2' into thermal energy and release it, and the neutron flux density itself is considerably attenuated and the shielding bodies 3, 3 Most of it is absorbed there, but some of it is absorbed by radioactive nuclides due to a nuclear reaction with the nuclides contained in the sterene steel that is the constituent material of the shields 3 and 3'. Generate (radiate). For example, radionuclides generated by reactions such as 58 Ni (n, p) 58 Co, 56 Fe (n, p) 54 Nn continue to emit gamma rays through radioactive decay even after the reactor is shut down, and workers approaching the shield 3' cause radioactive exposure to people. Therefore, as a countermeasure, as shown in Fig. 2, lead 10, which hardly becomes radioactive and has good shielding performance against gamma rays, is stretched outside the shield 3' to absorb gamma rays 14 and prevent workers from The radiation dose for those affected was reduced. However, as shown in FIG.
However, so-called streaming occurs, in which gamma rays pass through the coolant 16, which has a weak shielding ability against gamma rays 14, and this causes an increase in the radiation dose of workers outside the shield, and countermeasures are urgently needed. .
本発明は上記実情に鑑み、核融合炉における遮
蔽体の冷却配管貫通部におけるガンマ線ストリー
ミングの防止機構を提供せんとするものである。 In view of the above-mentioned circumstances, the present invention aims to provide a mechanism for preventing gamma ray streaming at a cooling pipe penetration portion of a shield in a nuclear fusion reactor.
即ち、本発明は遮蔽体中を貫通するブランケツ
ト，ダイバータ等を冷却するための多数の冷却配
管を遮蔽体の中央部でＳ字状に折り曲げて設置
し、そのＳ字状配管の遮蔽体の外側貫通部の周り
に鉛遮蔽体を設けて、遮蔽体構成材料の放射化し
た放射性核種から放出される崩壊ガンマ線のスト
リーミングによる遮蔽体外側への漏洩を防止し
て、該遮蔽体外側での線量増大を抑止することを
特徴とするものである。 That is, in the present invention, a large number of cooling pipes for cooling blankets, diverters, etc. passing through the shield are bent into an S-shape at the center of the shield, and the S-shaped pipes are installed outside the shield. A lead shield is provided around the penetration part to prevent leakage of decay gamma rays emitted from activated radionuclides of the shield constituent material to the outside of the shield due to streaming, thereby increasing the dose outside the shield. It is characterized by suppressing.
以下本発明の一実施例について詳細に説明す
る。 An embodiment of the present invention will be described in detail below.
第４図に於て、１５′は第１図における内・外
側ブランケツト２，２′、ダイバータ／リミタ６
等を冷却するための多数の冷却配管が遮蔽体３′
中を貫通している部分中の、冷却配管の一本を代
表例として示したもので、Ｓ字状に折り曲げられ
ている。遮蔽材２０は容器２１の中に冷却配管１
５′の周りに充填されている。遮蔽材２０の外側
の壁面に、即ちプラズマ側と反対側の壁面に鉛１
０の遮蔽層を設け、該鉛遮蔽層１０を冷却配管１
５′の遮蔽体外側貫通部の周りに設けてある鉛遮
蔽層２２と一体をなしている。遮蔽体の寸法諸元
は全体厚さｌ、冷却配管１５′のＳ字状曲げ部の
中心から鉛遮蔽層１０を含んだ外側貫通部厚さ
l1、冷却配管１５′のＳ字状曲げの曲げ間隔l2、該
冷却配管１５′の外側貫通部の鉛遮蔽層２２の長
さl3、その厚さｔである。l1，l2の長さは炉運転
時の中性子による構造材の放射化量が最少となる
ように理論的，実験的に決定される。l3と厚さｔ
は炉停止後の許容される放射線々量レベルとのか
ねあいで決定されるもので、許容レベルが厳しい
程、l3とｔは大きくなる。 In FIG. 4, 15' is the inner/outer blanket 2, 2', diverter/limiter 6 in FIG.
A large number of cooling pipes for cooling etc. are connected to the shield 3'.
This is a representative example of one of the cooling pipes in the part that penetrates the inside, and is bent into an S-shape. The shielding material 20 has a cooling pipe 1 inside the container 21.
Filled around 5'. Lead 1 is placed on the outer wall surface of the shielding material 20, that is, on the wall surface opposite to the plasma side.
0 shielding layer is provided, and the lead shielding layer 10 is connected to the cooling pipe 1.
It is integral with a lead shielding layer 22 provided around the outer shield penetration of 5'. The dimensions of the shield are the overall thickness l, and the thickness of the outer penetrating part including the lead shield layer 10 from the center of the S-shaped bend of the cooling pipe 15'.
l 1 , the bending interval l 2 of the S-shaped bend of the cooling pipe 15', the length l 3 of the lead shielding layer 22 at the outer penetrating portion of the cooling pipe 15', and its thickness t. The lengths of l 1 and l 2 are determined theoretically and experimentally to minimize the amount of activation of structural materials by neutrons during reactor operation. l 3 and thickness t
is determined based on the allowable radiation dose level after the reactor is shut down, and the stricter the allowable level, the larger l 3 and t become.
次に上述の如く構成した本実施例の作用につい
て説明する。遮蔽体３′は運転中容器２１の壁面
を通過して入射して来る中性子の殆んどを遮蔽材
２０中に吸収してしまう。しかしながら一部中性
子が構成材料であるステンレス鋼の含有核種との
核反応によつて放射化するのを防止するために、
遮蔽体中央部で、冷却配管１５′をＳ字状に折り
曲げている。そのため中性子が遮蔽体３′の奥深
くまで直進するのが防止されるので、高速中性子
の冷却材１６中のストリーミングによる遮蔽体構
成材料の放射化領域が内側に制限され、しかも放
射化の増大が抑止される。更に冷却配管１５′の
外側貫通部の周囲に鉛遮蔽層２２を設置している
ので、放射化した遮蔽体３′から放出されて冷却
材１６中に流入する崩壊ガンマ線が減少せしめら
れる。 Next, the operation of this embodiment configured as described above will be explained. During operation, the shielding body 3' absorbs most of the neutrons that pass through the wall surface of the container 21 into the shielding material 20. However, in order to prevent some neutrons from becoming radioactive due to nuclear reactions with the nuclides contained in the stainless steel that is the constituent material,
The cooling pipe 15' is bent into an S-shape at the center of the shield. Therefore, neutrons are prevented from going straight deep into the shield 3', so the activation area of the shield material due to fast neutron streaming in the coolant 16 is restricted to the inside, and an increase in activation is suppressed. be done. Furthermore, since the lead shielding layer 22 is provided around the outer penetration portion of the cooling pipe 15', the decay gamma rays emitted from the activated shielding body 3' and flowing into the coolant 16 are reduced.
以上詳述した通り本発明は遮蔽体中にＳ字状の
冷却配管を設置し、該冷却配管の外側貫通部の周
囲に鉛の遮蔽材を設けるのであるから、ストリー
ミングしてくる中性子と遮蔽体含有核種との放射
化反応を遮蔽体の内側領域に制限し、放射化の増
大を防止し、且つ放射化した遮蔽体から放出され
冷却材中に流入する崩壊ガンマ線を減衰させ、遮
蔽体外側における作業従事者の被曝線量を低減化
することが出来るという優れた効果がある。 As detailed above, in the present invention, an S-shaped cooling pipe is installed in the shield, and a lead shielding material is provided around the outer penetration part of the cooling pipe, so streaming neutrons and the shield The activation reaction with the contained nuclides is restricted to the inner region of the shield, preventing an increase in activation, and attenuating the decay gamma rays emitted from the activated shield and flowing into the coolant, and reducing the amount of radiation outside the shield. It has the excellent effect of reducing the exposure dose of workers.
第１図はトカマク型核融合炉の概略を示す断面
図、第２図は従来の遮蔽体における崩壊ガンマ線
ストリーミングの概念図、第３図は従来の遮蔽体
における冷却配管貫通部の崩壊ガンマ線ストリー
ミングの概念図、第４図は本発明による崩壊ガン
マ線ストリーミング防止機構を示す概念図であ
る。
１０…鉛遮蔽層、１５…冷却配管、１６…冷却
材、２０…遮蔽材、２２…鉛遮蔽層。
Figure 1 is a cross-sectional view schematically showing a tokamak-type fusion reactor, Figure 2 is a conceptual diagram of decay gamma-ray streaming in a conventional shield, and Figure 3 is a conceptual diagram of decay gamma-ray streaming in a cooling piping penetration in a conventional shield. Conceptual diagram, FIG. 4 is a conceptual diagram showing a decay gamma ray streaming prevention mechanism according to the present invention. DESCRIPTION OF SYMBOLS 10... Lead shielding layer, 15... Cooling piping, 16... Coolant, 20... Shielding material, 22... Lead shielding layer.
Claims (1)
管を遮蔽体の中央部でＳ字状に曲げて設置し、該
冷却配管の遮蔽体外側貫通部の周囲に鉛遮蔽層を
設け、該鉛遮蔽層を遮蔽体外側壁面に張設された
鉛遮蔽層と一体となして、遮蔽体構成材料の放射
化した放射性核種から放出される崩壊ガンマ線が
配管の周囲から配管内入射するのを抑制するよう
にしたことを特徴とする崩壊ガンマ線ストリーミ
ング防止機構。1. A large number of cooling pipes penetrating through the shield of a fusion reactor are bent into an S-shape at the center of the shield, and a lead shielding layer is provided around the part of the cooling pipe that penetrates the outside of the shield. The lead shielding layer is integrated with the lead shielding layer stretched on the outside wall of the shield to suppress decay gamma rays emitted from activated radionuclides in the shielding material from entering the pipe from around the pipe. A decay gamma ray streaming prevention mechanism characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59013060A JPS60157093A (en) | 1984-01-27 | 1984-01-27 | Decay gammas streaming preventive mechanism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59013060A JPS60157093A (en) | 1984-01-27 | 1984-01-27 | Decay gammas streaming preventive mechanism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60157093A JPS60157093A (en) | 1985-08-17 |
| JPH047840B2 true JPH047840B2 (en) | 1992-02-13 |
Family
ID=11822582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59013060A Granted JPS60157093A (en) | 1984-01-27 | 1984-01-27 | Decay gammas streaming preventive mechanism |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60157093A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6224180A (en) * | 1985-07-24 | 1987-02-02 | 株式会社東芝 | Baking exhauster for nuclear fusion device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56153900U (en) * | 1980-04-18 | 1981-11-17 | ||
| JPS5871490A (en) * | 1981-10-23 | 1983-04-28 | 株式会社日立製作所 | Shielding structure of air duct through portion |
-
1984
- 1984-01-27 JP JP59013060A patent/JPS60157093A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60157093A (en) | 1985-08-17 |
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