JP2590241B2 - Fuel assembly - Google Patents
Fuel assemblyInfo
- Publication number
- JP2590241B2 JP2590241B2 JP63293569A JP29356988A JP2590241B2 JP 2590241 B2 JP2590241 B2 JP 2590241B2 JP 63293569 A JP63293569 A JP 63293569A JP 29356988 A JP29356988 A JP 29356988A JP 2590241 B2 JP2590241 B2 JP 2590241B2
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- tie plate
- fuel rod
- cylindrical spring
- projection
- 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
- Y02E30/30—Nuclear fission reactors
Landscapes
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Fuel-Injection Apparatus (AREA)
Description
【発明の詳細な説明】 〔発明の目的〕 （産業上の利用分野） 本発明は、原子炉の炉心部に装荷される燃料集合体に
係り、特に燃料棒の上部が欠除した短尺燃料棒あるいは
燃料棒の上部が固定されていない燃料棒の輸送中の移
動、運転中での浮き上り、および回転を防止すべく改良
された燃料集合体に関する。Description: Object of the Invention (Industrial application field) The present invention relates to a fuel assembly loaded in a core of a nuclear reactor, and in particular, to a short fuel rod in which an upper part of a fuel rod is omitted. Alternatively, the present invention relates to a fuel assembly improved so as to prevent movement of a fuel rod having an upper portion not fixed during transportation, floating during operation, and rotation.
（従来の技術） 沸騰水形原子炉の燃料集合体は、角筒状のチャンネル
内に多数の燃料棒を例えば８行、８列のマトリックス状
に配列し、これらの燃料棒の上下端を上部タイプレート
および下部タイプレートによって支持し、上部、下部両
タイプレート間に適切な間隔で配設された複数のスペー
サにて支持することにより燃料棒相互の間隔を一定に保
つように構成されている。(Prior Art) In a fuel assembly of a boiling water reactor, a large number of fuel rods are arranged in a rectangular tubular channel in, for example, an eight-row, eight-row matrix, and the upper and lower ends of these fuel rods are placed in the upper part. It is configured to support the tie plate and the lower tie plate, and to keep the distance between the fuel rods constant by supporting with a plurality of spacers arranged at appropriate intervals between the upper and lower tie plates. .
また、各燃料棒は、酸化ウランの粉末を焼結して円柱
状に形成した多数のペレットを円筒状の被覆管内部に積
重ねて収納すると共に、燃料被覆管上部なプレナムスプ
リングを介して上部端栓にて、被覆管下部は下部端栓に
てそれぞれ密封している。In addition, each fuel rod contains a large number of pellets formed by sintering uranium oxide powder in a columnar shape and stacked inside a cylindrical cladding tube, and has an upper end through a plenum spring at the top of the fuel cladding tube. The lower portion of the cladding tube is sealed with a lower end plug.
ところで、近年、上記複数の燃料棒の一部に、ほぼ上
半部を欠除して短小に形成させた短尺燃料棒を配列する
ことが提案されている（例えば特願昭57−12821）。こ
の目的は、この公報にて詳細に説明されているように、
沸騰水形原子炉では、通常炉心上部にプルトニウム（P
u）が多く蓄積されており、原子炉運転停止時には炉心
上部の反応度が炉心下部に比し高い傾向になるから、こ
れを考慮して燃料集合体上部においてウラン量を減少さ
せ、これにより水／ウラン比を高め、運転停止時の無限
増倍率Ｋ∞を僅かなウランの減量によって効果的に低下
させ、原子炉の安全性を向上させるためである。Meanwhile, in recent years, it has been proposed to arrange short fuel rods, which are formed in a small size by removing substantially the upper half thereof, in a part of the plurality of fuel rods (for example, Japanese Patent Application No. 57-12821). The purpose is, as explained in detail in this publication,
In a boiling water reactor, plutonium (P
u) is accumulated in large quantities, and when the reactor is shut down, the reactivity in the upper part of the core tends to be higher than that in the lower part of the core. The reason is to increase the / uranium ratio and effectively reduce the infinite multiplication factor K∞ when the operation is stopped by slightly reducing the amount of uranium, thereby improving the safety of the reactor.
（発明が解決しようとする課題） しかしながら、従来の燃料集合体に上述の短尺燃料棒
をその一部に採用した場合、構造上から以下の問題が生
じていた。すなわち、上下部タイプレート間を結合して
いる結合燃料棒以外の通常の長尺な燃料棒と下部タイプ
レートとの結合構成は、下部端栓に設けてある丸軸を下
部タイプレートの燃料棒支持用丸孔に嵌合させただけの
構造である。そのため、上部タイプレートにその上端が
支持されないことになった短尺燃料棒は、輸送中におい
て移動し、また、原子炉運転中において浮き上ることが
あり、その健全性に問題が生じてる可能性がある。(Problems to be Solved by the Invention) However, when the above-mentioned short fuel rods are used as a part of the conventional fuel assembly, the following problems occur due to the structure. That is, the connection structure of the lower tie plate and the normal long fuel rod other than the connection fuel rod connecting the upper and lower tie plates is such that the round shaft provided on the lower end plug is connected to the lower tie plate fuel rod. This is a structure that is simply fitted into the support round hole. Therefore, the short fuel rod whose upper end is not supported by the upper tie plate may move during transportation and may float during operation of the reactor, which may cause a problem with its soundness. is there.
そこで、本発明は上述の事情を考慮してなされたもの
で、上部を欠除した燃料棒、すなわち短尺燃料棒あるい
は、燃料棒の上部が固定されていない燃料棒を一部に備
えた燃料集合体において、この短尺燃料棒の輸送中の移
動あるいは運転中の浮き上りを防止する構成を有してい
る燃料集合体を提供することを目的とする。Therefore, the present invention has been made in view of the above circumstances, and a fuel assembly partially provided with a fuel rod lacking an upper portion, that is, a short fuel rod or a fuel rod having an upper portion not fixed. It is an object of the present invention to provide a fuel assembly having a structure for preventing the short fuel rod from moving during transportation or floating during operation.
（課題を解決するための手段） 上部、下部両端栓により上下両端を封止せしめた複数
本の燃料棒と、この燃料棒の上下端を支持する上下部タ
イプレートと、上下部タイプレート間に適当な間隔で配
設され、燃料棒相互を適宜間隔で保持する複数のスペー
サとを燃料チャンネル内に収容せしめる燃料集合体にお
いて、燃料棒の上部が欠除した短尺燃料棒あるいは燃料
棒の上部が固定されていない燃料棒の下部端栓が挿入さ
れるべく位置の下部タイプレートの挿入孔に、当該燃料
を固定するための円筒型バネを設け、またこの円筒型バ
ネと嵌合するように下部端栓の丸軸にくびれ部を設け
る。(Means for Solving the Problems) A plurality of fuel rods whose upper and lower ends are sealed by upper and lower end plugs, an upper and lower tie plate supporting the upper and lower ends of the fuel rod, and an upper and lower tie plate In a fuel assembly in which a plurality of spacers arranged at appropriate intervals and holding the fuel rods at appropriate intervals are accommodated in a fuel channel, a short fuel rod or an upper portion of a fuel rod in which an upper portion of the fuel rod is omitted is provided. A cylindrical spring for fixing the fuel is provided in the insertion hole of the lower tie plate at a position where the lower end plug of the fuel rod that is not fixed is inserted, and the lower part is fitted so as to fit with the cylindrical spring. A constriction is provided on the round shaft of the end plug.
（作用） 燃料棒の輸送中の移動および原子炉運転中の浮き上が
りを防止できる。(Operation) It is possible to prevent the movement of the fuel rod during transportation and the lifting of the fuel rod during operation of the reactor.
（実施例） 本発明に係わる燃料集合体の一例の全体構成を第１図
に示す。角筒状のチャンネル１内に、上下端が上部下部
端栓11,14によって密封されている多数の燃料棒10を１
列８本で８列にしたマトリックス状に収納配列し、燃料
棒10の上端を上部タイプレート２にて、下端を下部タイ
プレート４にて夫々支持すると共に、上部、下部両タイ
プレート2,4間に適切な間隔で配設された複数のスペー
サ６にて、燃料棒10相互を適宜間隔で保持して成る。燃
料棒10の一部は、上部のみを欠除した短尺燃料棒10Aで
構成されている。この短尺燃料棒10Aの配置は燃料集合
体の核設計により変化するが、一例を第２図に示す。集
合体の四隅に近い位置に短尺燃料棒10Aが組込まれてい
る。(Example) FIG. 1 shows the overall configuration of an example of a fuel assembly according to the present invention. A large number of fuel rods 10 whose upper and lower ends are sealed by upper and lower end plugs 11 and 14 are placed in a rectangular tubular channel 1.
The fuel rods 10 are arranged and arranged in an eight-row matrix, and the upper end of the fuel rod 10 is supported by the upper tie plate 2 and the lower end thereof is supported by the lower tie plate 4, and both upper and lower tie plates 2 and 4 are supported. The fuel rods 10 are held at appropriate intervals by a plurality of spacers 6 arranged at appropriate intervals therebetween. A part of the fuel rod 10 is constituted by a short fuel rod 10A in which only the upper part is omitted. The arrangement of the short fuel rods 10A varies depending on the nuclear design of the fuel assembly. An example is shown in FIG. Short fuel rods 10A are incorporated near the four corners of the assembly.
短尺燃料棒10Aの構造を第３図に示す。短尺燃料棒10A
の下部端栓７の丸軸部7Bの根元部分の径をわずかに細く
したくびれ部7Aを設けているのが特徴である。FIG. 3 shows the structure of the short fuel rod 10A. Short fuel rod 10A
It is characterized in that a constricted portion 7A is provided in which the diameter of the root portion of the round shaft portion 7B of the lower end plug 7 is slightly reduced.
第４図は短尺燃料棒10Aの下部端栓７に挿入されるべ
く位置の下部タイプレート４の挿入孔に、当該燃料を固
定するために設けられる円筒型バネ20の概略を示したも
のである。この円筒型バネ20には、上下に複数のスリッ
ト21が入っており、上端部分22で外側に広がり、下端に
近い部分で外側に突起23を有し、さらに中間部分では内
側に突起24を有している。FIG. 4 schematically shows a cylindrical spring 20 provided to fix the fuel in the insertion hole of the lower tie plate 4 at a position to be inserted into the lower end plug 7 of the short fuel rod 10A. . The cylindrical spring 20 has a plurality of slits 21 at the top and bottom, which spreads outward at an upper end portion 22, has a projection 23 at a portion near the lower end, and has a projection 24 at an intermediate portion. doing.
自由状態における円筒型バネ20の外側へ広がっている
上端部分22の外径および外側への突起23部分の外径は、
下部タイプレート４挿入孔の内径より大きく、また円筒
型バネ20の内側への突起24部分の内径は、下部端栓７の
丸軸部7Bのくびれ部7Aの外径より若干小さくしている。In the free state, the outer diameter of the upper end portion 22 and the outer diameter of the outwardly projecting portion 23 extending outwardly of the cylindrical spring 20 are:
The inner diameter of the protrusion 24 into the cylindrical spring 20 is larger than the inner diameter of the lower tie plate 4 insertion hole, and is slightly smaller than the outer diameter of the constricted portion 7A of the round shaft portion 7B of the lower end plug 7.
短尺燃料棒10Aが挿入されるべき位置の下部タイプレ
ート４の挿入孔に円筒型バネ20を取付けた状態の断面図
を第５図に示す。円筒型バネ20を下部タイプレート４の
上部から挿入し取付ける。取付けた後では同図に示され
ているように円筒型バネ20は、上端部分22での外側への
広がりおよび下端に近い部分での外側への突起23によ
り、下部タイプレート４挿入孔内での上下方向の移動が
防止される構造となっている。これに短尺燃料棒10Aの
下部端栓７を挿入した状態の断面図を第６図に示す。円
筒型バネ20の中間部分の内側への突起24と短尺燃料棒10
Aの下部端栓７の丸軸部7Bの根元部分のくびれ部7Aとが
嵌合している。これにより、短尺燃料棒10Aが集合体の
上下方向に移動することが防止されている。FIG. 5 is a sectional view showing a state where the cylindrical spring 20 is attached to the insertion hole of the lower tie plate 4 at the position where the short fuel rod 10A is to be inserted. A cylindrical spring 20 is inserted from above the lower tie plate 4 and attached. After installation, as shown in the figure, the cylindrical spring 20 is extended in the lower tie plate 4 insertion hole by the outward extension at the upper end portion 22 and the outward projection 23 near the lower end. In the vertical direction. FIG. 6 is a sectional view showing a state in which the lower end plug 7 of the short fuel rod 10A is inserted therein. The protrusion 24 and the short fuel rod 10 on the inside of the middle part of the cylindrical spring 20
A round end 7B of the round shaft 7B of the lower end plug 7 of A is fitted with a constricted portion 7A. This prevents the short fuel rod 10A from moving in the vertical direction of the assembly.
円筒型バネ20は、上下にスリットが入り板バネとなっ
ており、下部タイプレート４挿入孔と短尺燃料棒10A下
部端栓７とを上下方向に固定しつなぐ役目をしている。The cylindrical spring 20 is a leaf spring having slits at upper and lower sides, and serves to fix and connect the lower tie plate 4 insertion hole and the short fuel rod 10A lower end plug 7 in the vertical direction.
本発明の燃料集合体の組立て手順を具体的に説明す
る。The procedure for assembling the fuel assembly of the present invention will be specifically described.
（１） 短尺燃料棒10Aが挿入されるべき位置の下部タ
イプレートの挿入孔に円筒型バネ20を上部から押込み取
付ける。(1) The cylindrical spring 20 is pushed from above into the insertion hole of the lower tie plate at the position where the short fuel rod 10A is to be inserted.
（２） 円筒型バネ20を取付けた位置に短尺燃料棒10A
を上部から挿入する。すなわち、円筒型バネ20内に短尺
燃料棒10Aの下部端栓７を挿入する。円筒型バネ20の中
間部分の内側への突起24と短尺燃料棒10Aの下部端栓７
のくびれ部7Aとが嵌合するまで挿入する。(2) Short fuel rod 10A at the position where the cylindrical spring 20 is attached
Insert from the top. That is, the lower end plug 7 of the short fuel rod 10A is inserted into the cylindrical spring 20. Projection 24 inward of the middle part of cylindrical spring 20 and lower end plug 7 of short fuel rod 10A
Insert until the constriction 7A fits.
（３） その他の燃料棒を組立てる。(3) Assemble other fuel rods.
円筒型バネ20はどの位置の下部タイプレート４挿入孔
にも装着可能な形状である。このことは核設計の変更に
ともない短尺燃料棒10Aの集合体内の位置が変更になっ
たとしても、円筒型バネ20の下部タイプレート４挿入孔
への装着位置を変更し、集合体を組立てることにより対
応可能であり、下部タイプレートなどの燃料集合体の部
品の設計変更をしなくてよい。また、短尺燃料棒10Aが
何本になっても対応可能である。The cylindrical spring 20 has a shape that can be mounted in the lower tie plate 4 insertion hole at any position. This means that even if the position of the short fuel rod 10A in the assembly is changed due to the change in the nuclear design, the mounting position of the cylindrical spring 20 in the lower tie plate 4 insertion hole should be changed and the assembly should be assembled. And the design of the fuel assembly components such as the lower tie plate need not be changed. In addition, it is possible to cope with any number of short fuel rods 10A.
燃料集合体の輸送中においての短尺燃料棒の移動を防
止し、輸送中の燃料棒の健全性を維持できると共に、原
子炉運転中での短尺燃料棒の浮き上りを完全に防止して
下部タイプレートからの離脱を未然に、かつ確実に防止
できる等の優れた効果を奏するものである。The lower type can prevent the movement of short fuel rods during transportation of the fuel assembly, maintain the integrity of fuel rods during transportation, and completely prevent the lifting of short fuel rods during reactor operation. An excellent effect is obtained such that the departure from the rate can be prevented beforehand and surely.
第１図は本発明の燃料集合体の全体構成を示す図、第２
図は本発明にかかる短尺燃料棒の集合体内の配置例を示
す図、第３図は本発明にかかる短尺燃料棒の構造を示す
図、第４図は本発明にかかる円筒型バネの概略図、第５
図は本発明の燃料集合体の短尺燃料棒下部組立て状態を
示す図、第６図は本発明の燃料集合体の組立て状態を示
す図である。 １……チャンネル、２……上部タイプレート ４……下部タイプレート、６……スペーサ ７……下部端栓、7A……下部端栓のくびれ部 7B……端栓丸軸部分、10……燃料棒 10A……短尺燃料棒、10B……結合燃料棒 11……上部端栓、16……ペレット 17……燃料被覆管、18……プレナムスプリ 20……円筒型バネ、21……スリット 23……突起、24……突起FIG. 1 is a view showing the overall configuration of a fuel assembly according to the present invention, and FIG.
FIG. 3 is a view showing an example of the arrangement of short fuel rods according to the present invention in an assembly, FIG. 3 is a view showing the structure of a short fuel rod according to the present invention, and FIG. 4 is a schematic view of a cylindrical spring according to the present invention. , Fifth
FIG. 6 is a view showing a fuel assembly according to the present invention in a state where a short fuel rod is assembled to a lower portion, and FIG. 6 is a view showing an assembly state of the fuel assembly in the present invention. 1 ... channel, 2 ... upper tie plate 4 ... lower tie plate, 6 ... spacer 7 ... lower end plug, 7A ... constriction of lower end plug 7B ... round end plug end, 10 ... Fuel rod 10A …… Short fuel rod, 10B …… Combined fuel rod 11 …… Top end plug, 16 …… Pellet 17 …… Fuel cladding tube, 18 …… Plenum splice 20 …… Cylindrical spring, 21 …… Slit 23 ... Projection, 24 Projection
Claims (2)
しめた複数本の燃料棒と、この燃料棒の上下端を支持す
る上部、下部両タイプレートと、これら両タイプレート
間に適切な間隔で配設され、燃料棒相互を適宜間隔で保
持する複数のスペーサとを燃料チャンネル内に収容せし
める燃料集合体において、燃料棒の上端部が固定されて
いない燃料棒の下部端栓が挿入されるべく位置の下部タ
イプレートの挿入孔に、内側に突起を有する円筒型バネ
を設け、この円筒型バネの突起と嵌合する位置に下部端
栓の軸にくびれ部を設けたことを特徴とする燃料集合
体。1. A plurality of fuel rods having upper and lower ends sealed by upper and lower end plugs, upper and lower tie plates supporting the upper and lower ends of the fuel rods, and an appropriate In a fuel assembly in which a plurality of spacers arranged at intervals and holding the fuel rods at appropriate intervals are accommodated in the fuel channel, the lower end plug of the fuel rod whose upper end is not fixed is inserted. A cylindrical spring having a projection on the inner side is provided in the insertion hole of the lower tie plate at a position as much as possible, and a constriction is provided on the shaft of the lower end plug at a position where the projection is fitted with the projection of the cylindrical spring. Fuel assembly.
バネは、上下に複数のスリットが入っており、下部タイ
プレートの上面に位置する部分で外側に広がり、下部タ
イプレートの下面に位置する部分で外側に突起を有して
いることを特徴とする請求項１記載の燃料重合体。2. The cylindrical spring inserted and fixed in the lower tie plate has a plurality of slits at the top and bottom, spreads outward at a portion located on the upper surface of the lower tie plate, and is located on the lower surface of the lower tie plate. The fuel polymer according to claim 1, wherein the portion has a projection on the outside.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63293569A JP2590241B2 (en) | 1988-11-22 | 1988-11-22 | Fuel assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63293569A JP2590241B2 (en) | 1988-11-22 | 1988-11-22 | Fuel assembly |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02140689A JPH02140689A (en) | 1990-05-30 |
| JP2590241B2 true JP2590241B2 (en) | 1997-03-12 |
Family
ID=17796439
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63293569A Expired - Lifetime JP2590241B2 (en) | 1988-11-22 | 1988-11-22 | Fuel assembly |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2590241B2 (en) |
Cited By (1)
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|---|---|---|---|---|
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2864326B1 (en) * | 2003-12-22 | 2006-02-24 | Framatome Anp | METHOD FOR LIMITING HOLDING EFFORTS EXERCISED ON FUEL ASSEMBLY OF A NUCLEAR REACTOR AND FUEL ASSEMBLY |
| DE102004059195B3 (en) * | 2004-12-09 | 2006-02-23 | Framatome Anp Gmbh | Fuel element for a boiling water nuclear reactor, comprises a foot, a sieve plate, a fuel element head and a bundle of longitudinal fuel rods |
| EP2405443A1 (en) | 2010-07-06 | 2012-01-11 | Areva NP | BWR nuclear fuel assembly with snap-in sleeve spring |
| JP7316232B2 (en) * | 2020-01-21 | 2023-07-27 | 日立Ｇｅニュークリア・エナジー株式会社 | fuel assembly |
-
1988
- 1988-11-22 JP JP63293569A patent/JP2590241B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9257684B2 (en) | 2012-09-04 | 2016-02-09 | Panasonic Intellectual Property Management Co., Ltd. | Battery block and manufacturing method therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02140689A (en) | 1990-05-30 |
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