JPH07244179A - Upper end plug of fuel rod - Google Patents
Upper end plug of fuel rodInfo
- Publication number
- JPH07244179A JPH07244179A JP6064625A JP6462594A JPH07244179A JP H07244179 A JPH07244179 A JP H07244179A JP 6064625 A JP6064625 A JP 6064625A JP 6462594 A JP6462594 A JP 6462594A JP H07244179 A JPH07244179 A JP H07244179A
- Authority
- JP
- Japan
- Prior art keywords
- end plug
- vent hole
- welding
- fuel rod
- hole
- 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
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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、原子燃料用燃料棒の成
型加工の最終段階で実施するヘリウム加圧状態での上部
端栓の封詰溶接に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing welding of an upper end plug under pressure of helium, which is carried out at the final stage of forming a fuel rod for nuclear fuel.
【０００２】[0002]
【従来の技術】燃料集合体を構成する燃料棒は、被覆管
の内部に多数の燃料ペレットやプレナムスプリングを装
填し、この被覆管の上下部に上部端栓と下部端栓とを夫
々溶接したものである。そしてこの燃料棒は、冷却材の
圧力によって被覆管がクリープコラプスを起こさないよ
う、また燃料ペレットと被覆管の間のギャップ熱伝導率
を高めるなどの目的で、内部にヘリウムガスが加圧封詰
される。2. Description of the Related Art A fuel rod constituting a fuel assembly has a cladding tube in which a large number of fuel pellets and plenum springs are loaded, and an upper end plug and a lower end plug are welded to the upper and lower parts of the cladding tube, respectively. It is a thing. This fuel rod is filled with helium gas under pressure to prevent creep collapse of the cladding due to the pressure of the coolant and to increase the thermal conductivity of the gap between the fuel pellet and the cladding. To be done.
【０００３】上記ヘリウムガスの加圧封詰は、燃料棒の
上部をチャンバーの加圧室内に挿入し、上部端栓５′を
軸方向に貫通したベントホールから上記燃料棒内に加圧
ガスを導入した後、図５に示す如くベントホール７′の
中心位置に電極１５を位置決めし、ＴＩＧ溶接にてベン
トホールを溶接することによって行われている。To pressurize the helium gas under pressure, the upper part of the fuel rod is inserted into the pressure chamber of the chamber, and the pressurized gas is introduced into the fuel rod through a vent hole axially penetrating the upper end plug 5 '. After the introduction, the electrode 15 is positioned at the center of the vent hole 7'as shown in FIG. 5, and the vent hole is welded by TIG welding.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記従
来の上部端栓の封詰方法においては、溶接を行うに際し
ては燃料棒１本毎に上部端栓と電極との間のギャップ調
整を行わねばならず、また電極の寿命も短いために頻繁
に電極交換を行う必要があり、溶接作業に時間を要する
という問題を有している。However, in the above-mentioned conventional method of sealing the upper end plug, the gap between the upper end plug and the electrode must be adjusted for each fuel rod when welding is performed. In addition, since the life of the electrode is short, it is necessary to replace the electrode frequently, and there is a problem that the welding operation takes time.
【０００５】本発明は叙上の如き実状に対処し、上部端
栓をレーザー溶接に適する形状に改良して溶接手段をレ
ーザー溶接に変更することにより、上記燃料棒１本毎の
電極のギャップ調整や電極の寿命の問題をなくし、燃料
棒上部端栓の封詰を効率良く行わしめることを目的とす
るものである。The present invention copes with the above situation, and the upper end plug is modified into a shape suitable for laser welding and the welding means is changed to laser welding, whereby the electrode gap adjustment for each fuel rod is performed. The purpose of the present invention is to eliminate the problem of the life of the electrode and the electrode and to efficiently seal the upper end plug of the fuel rod.
【０００６】[0006]
【課題を解決するための手段】即ち、上記目的に適合す
る本発明の上部端栓の特徴は、前述の如く燃料棒被覆管
の上部に溶接され、軸方向に被覆管内へ加圧ガスを導入
するためのベントホールが貫設された上部端栓におい
て、この上部端栓上面の上記ベントホール周囲に、溶融
することによりベントホールに吸い込まれこのベントホ
ール端部を閉塞する溶接用突起を形成せしめたところに
ある。That is, the feature of the upper end plug of the present invention which meets the above object is that the upper end plug of the present invention is welded to the upper portion of the fuel rod cladding tube as described above, and the pressurized gas is introduced into the cladding tube in the axial direction. In the upper end plug through which the vent hole is formed, a welding protrusion is formed around the vent hole on the upper surface of the upper end plug to be sucked into the vent hole by melting and close the end part of the vent hole. It's right there.
【０００７】[0007]
【作用】上記本発明の上部端栓では、レーザー光によっ
て上記溶接用突起を溶融させることにより、溶融した突
起が毛管現象によってベントホール端部に入り込み、こ
のベントホールを閉塞するものであり、レーザー光を突
起に照射するとの極めて簡単な工程で上部端栓の封詰を
行うことが可能である。In the upper end plug of the present invention, the welding projections are melted by the laser beam, and the melted projections enter the ends of the vent holes by the capillarity and close the vent holes. The upper end plug can be sealed by a very simple process of irradiating the projection with light.
【０００８】[0008]
【実施例】以下さらに添付図面を参照し、本発明の実施
例を説明する。Embodiments of the present invention will be described below with reference to the accompanying drawings.
【０００９】図１は本発明実施例の上部端栓を示す一部
断面図、図２は同実施例の上部端栓を用いた封詰方法示
す断面図、図３は同方法により封詰した上部端栓を示す
拡大断面図、図４は燃料棒の概要図である。FIG. 1 is a partial sectional view showing an upper end plug according to an embodiment of the present invention, FIG. 2 is a sectional view showing a sealing method using the upper end plug according to the same embodiment, and FIG. FIG. 4 is an enlarged sectional view showing the upper end plug, and FIG. 4 is a schematic view of the fuel rod.
【００１０】図４に示すように、燃料棒１は、被覆管２
の内部に多数の核燃料ペレット３とプレナムスプリング
４とを装填すると共に、被覆管２の上部に上部端栓５、
下部に下部端栓６を夫々溶着した構成を有している。As shown in FIG. 4, the fuel rod 1 includes a cladding tube 2
A large number of nuclear fuel pellets 3 and a plenum spring 4 are loaded in the interior of the reactor, and an upper end plug 5 is attached to the upper portion of the cladding tube 2.
The lower end plugs 6 are welded to the lower portions.
【００１１】そして、本発明実施例で使用する上部端栓
５は、図１に示す如く、この端栓の軸方向にベントホー
ル７が形成されると共に、端栓上面５ａの上記ベントホ
ール７の周囲に溶接用突起８が上部端栓５と同一材料に
よってリング状に一体形成されている。この溶接用突起
８は、後述するレーザー光によって溶融することによ
り、毛管現象によってベントホール７に吸い込まれ該ホ
ール端部を閉塞するものであり、図示の如く連続したリ
ング状でなく放射状に分割されたものであっても上記作
用効果は達成される。なお、上記ベントホール７の端栓
上面５ａでの直径は通常約0.5 〜1.0mm であり、これに
対し上記溶接用突起８の寸法は、高さＨ、厚みＤ、共に
約0.4 〜1.0mm が適当である。The upper end plug 5 used in the embodiment of the present invention has a vent hole 7 formed in the axial direction of the end plug as shown in FIG. A welding projection 8 is integrally formed around the periphery of the upper end plug 5 with the same material in a ring shape. The welding projections 8 are melted by a laser beam to be described later, and are sucked into the vent holes 7 by capillarity so as to close the ends of the holes. The above-mentioned operational effects can be achieved even if it is used. The diameter of the vent hole 7 on the upper surface 5a of the end plug is usually about 0.5 to 1.0 mm, while the dimensions of the welding projection 8 are about 0.4 to 1.0 mm for both height H and thickness D. Appropriate.
【００１２】一方、上記上部端栓を用いた加圧ガスの封
詰方法は、上記の如き上部端栓５を有する燃料棒１を用
い、図２に示す如く、この燃料棒１の上部をチャンバー
９の加圧室１０内に挿入し、上部端栓５のベントホール
７から燃料棒１内に約２５〜３５kg／cm2 のヘリウムガ
スを導入後、このベントホール７を封詰する。燃料棒１
の上部は、位置決めチャック機構１１で上記加圧チャン
バー９に固定され、さらにシール機構１２で加圧室１０
内に密閉される。On the other hand, in the method for sealing the pressurized gas using the upper end plug, the fuel rod 1 having the upper end plug 5 as described above is used, and as shown in FIG. After inserting the helium gas of about 25 to 35 kg / cm 2 into the fuel rod 1 from the vent hole 7 of the upper end plug 5, the vent hole 7 is sealed. Fuel rod 1
The upper part of the pressure chamber 10 is fixed to the pressure chamber 9 by the positioning chuck mechanism 11, and further the pressure chamber 10 is fixed by the sealing mechanism 12.
Sealed inside.
【００１３】即ち、上記実施例の封詰方法では、上記加
圧室１０において、上記固定した燃料棒上部端栓５のベ
ントホール７の軸線延長上に耐圧ガラスからなるレーザ
ー光透過部１３を形成し、このレーザー光透過部１３を
介し、上記ベントホールの軸線延長上のレーザーヘッド
１４から上部端栓５の前記溶接用突起８をレーザー光Ｌ
にて溶かし、毛管現象を利用して溶融した突起８をベン
トホール７内に吸い込ませることにより、図３に示す如
く上記ベントホール７を密封する。この場合、レーザー
光Ｌの直径は、溶接用突起８の差し渡し直径と同等の大
きさをもって、上記溶接用突起８全体を一度に溶融させ
ることが好適である。That is, in the sealing method of the above embodiment, the laser light transmitting portion 13 made of pressure resistant glass is formed in the pressurizing chamber 10 on the axial extension of the vent hole 7 of the fixed fuel rod upper end plug 5. Then, through the laser beam transmitting portion 13, the laser head 14 on the axial extension of the vent hole causes the laser beam L to pass through the welding projection 8 of the upper end plug 5.
Then, the protrusions 8 which are melted by using the capillary phenomenon are sucked into the vent holes 7 to seal the vent holes 7 as shown in FIG. In this case, it is preferable that the diameter of the laser beam L be as large as the diameter of the welding projection 8 and that the entire welding projection 8 be melted at once.
【００１４】しかして、上記本発明実施例の上部端栓を
用い、燃料棒上部端栓の封詰作業を行ったところ、レー
ザー光Ｌがベントホール７の軸線延長上からこのベント
ホール７に照射されて溶接が行われることから、従来の
如き燃料棒１本毎の電極のギャップ調整や電極の変換作
業が省略できることとなり、これにより上記上部端栓封
詰作業の迅速化と簡略化を図ることができた。When the upper end plug of the above-mentioned embodiment of the present invention was used to close the upper end plug of the fuel rod, the laser beam L was applied to the vent hole 7 from the axial extension of the vent hole 7. Since the welding is performed in this manner, it is possible to omit the conventional work of adjusting the electrode gap for each fuel rod and converting the electrode, which can speed up and simplify the work of sealing the upper end plug. I was able to.
【００１５】以上、本発明の実施例を説明したが、前記
溶接のためのレーザーは例えばＣＯ2 またはＹａｇレー
ザーなどが好適である。Although the embodiment of the present invention has been described above, the laser for welding is preferably a CO 2 or Yag laser, for example.
【００１６】[0016]
【発明の効果】以上説明したように、本発明の上部端栓
は、上部端栓上面のベントホール周囲に、溶融すること
によりベントホールに吸い込まれこのベントホール端部
を閉塞する溶接用突起を形成せしめたものであり、レー
ザー光を上記溶接用突起に照射するとの極めて簡単な工
程で上部端栓の封詰を行えることから、従来のＴＩＧ溶
接の如き燃料棒１本毎の電極のギャップ調整や電極の交
換作業が省略できることになり、これにより上記上部端
栓封詰作業の迅速化と簡略化を図れるとの顕著な効果を
奏するものである。As described above, the upper end plug of the present invention has the welding projection around the vent hole on the upper surface of the upper end plug which is sucked into the vent hole by being melted and closed at the end of the vent hole. Since the upper end plug can be sealed by a very simple process of irradiating the above-mentioned welding projection with laser light, it is possible to adjust the electrode gap for each fuel rod as in conventional TIG welding. This makes it possible to omit the work of exchanging the electrodes and the electrodes, which has a remarkable effect that the work of sealing the upper end plug can be speeded up and simplified.
【図１】本発明実施例の上部端栓を示す一部断面図であ
る。FIG. 1 is a partial sectional view showing an upper end plug of an embodiment of the present invention.
【図２】同実施例の上部端栓を用いた封詰方法を示す断
面図である。FIG. 2 is a cross-sectional view showing a sealing method using the upper end plug of the embodiment.
【図３】同方法により封詰した上部端栓を示す拡大断面
図である。FIG. 3 is an enlarged cross-sectional view showing an upper end plug sealed by the same method.
【図４】燃料棒の概要図である。FIG. 4 is a schematic view of a fuel rod.
【図５】従来の上部端栓の封詰方法を示す一部断面図で
ある。FIG. 5 is a partial sectional view showing a conventional method for sealing an upper end plug.
１ 燃料棒 ２ 被覆管 ３ 燃料ペレット ４ プレナムスプリング ５ 上部端栓 ５ａ 端栓上面 ６ 下部端栓 ７ ベントホール ８ 溶接用突起 ９ チャンバー １０ 加圧室 １１ チャック機構、 １２ シール機構 １３ レーザー光透過部 １４ レーザーヘッド DESCRIPTION OF SYMBOLS 1 Fuel rod 2 Cladding pipe 3 Fuel pellet 4 Plenum spring 5 Upper end plug 5a End plug upper surface 6 Lower end plug 7 Vent hole 8 Welding protrusion 9 Chamber 10 Pressurizing chamber 11 Chuck mechanism, 12 Sealing mechanism 13 Laser light transmitting part 14 Laser head
Claims (1)
に被覆管内へ加圧ガスを導入するためのベントホールが
貫設された上部端栓において、この上部端栓上面の上記
ベントホール周囲に、溶融することによりベントホール
に吸い込まれこのベントホール端部を閉塞する溶接用突
起を形成せしめたことを特徴とする燃料棒の上部端栓。1. An upper end plug which is welded to an upper portion of a fuel rod cladding tube and has a vent hole for axially introducing a pressurized gas into the cladding tube, wherein the vent hole is formed on an upper surface of the upper end plug. An upper end plug of a fuel rod, characterized in that a peripheral portion of a fuel rod is formed with a welding projection that is sucked into a vent hole when melted and closes the end of the vent hole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6064625A JPH07244179A (en) | 1994-03-07 | 1994-03-07 | Upper end plug of fuel rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6064625A JPH07244179A (en) | 1994-03-07 | 1994-03-07 | Upper end plug of fuel rod |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07244179A true JPH07244179A (en) | 1995-09-19 |
Family
ID=13263631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6064625A Pending JPH07244179A (en) | 1994-03-07 | 1994-03-07 | Upper end plug of fuel rod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07244179A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0795876A2 (en) * | 1996-03-11 | 1997-09-17 | General Electric Company | Apparatus and methods for sealing end plugs for nuclear fuel rods |
| CN109994221A (en) * | 2017-12-29 | 2019-07-09 | 中核建中核燃料元件有限公司 | A kind of nuclear fuel rod upper end plug |
| KR20190127431A (en) * | 2018-05-04 | 2019-11-13 | 한전원자력연료 주식회사 | Nuclear fuel rod with bamboo shape plenum adapted to increase internal volume thereof |
-
1994
- 1994-03-07 JP JP6064625A patent/JPH07244179A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0795876A2 (en) * | 1996-03-11 | 1997-09-17 | General Electric Company | Apparatus and methods for sealing end plugs for nuclear fuel rods |
| EP0795876A3 (en) * | 1996-03-11 | 1998-04-22 | General Electric Company | Apparatus and methods for sealing end plugs for nuclear fuel rods |
| CN109994221A (en) * | 2017-12-29 | 2019-07-09 | 中核建中核燃料元件有限公司 | A kind of nuclear fuel rod upper end plug |
| KR20190127431A (en) * | 2018-05-04 | 2019-11-13 | 한전원자력연료 주식회사 | Nuclear fuel rod with bamboo shape plenum adapted to increase internal volume thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 19990323 |