JPS63205596A - Neutron absorbing rod - Google Patents
Neutron absorbing rodInfo
- Publication number
- JPS63205596A JPS63205596A JP62035868A JP3586887A JPS63205596A JP S63205596 A JPS63205596 A JP S63205596A JP 62035868 A JP62035868 A JP 62035868A JP 3586887 A JP3586887 A JP 3586887A JP S63205596 A JPS63205596 A JP S63205596A
- Authority
- JP
- Japan
- Prior art keywords
- rod
- neutron
- neutron absorption
- pellet
- cladding tube
- 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
- 238000010521 absorption reaction Methods 0.000 claims description 39
- 239000008188 pellet Substances 0.000 claims description 31
- 238000005253 cladding Methods 0.000 claims description 20
- 229910052735 hafnium Inorganic materials 0.000 claims description 15
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 15
- 239000006096 absorbing agent Substances 0.000 claims description 6
- 229910052580 B4C Inorganic materials 0.000 claims description 4
- 239000011358 absorbing material Substances 0.000 claims description 4
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000463 material Substances 0.000 claims 2
- 230000003993 interaction Effects 0.000 description 6
- 239000000843 powder Substances 0.000 description 4
- 238000009835 boiling Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000011800 void material Substances 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
- Fluid-Damping Devices (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】
［産業上の利用分野］
本発明は沸騰水型原子炉の制御棒に用いられる中性子吸
収棒に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a neutron absorption rod used as a control rod of a boiling water nuclear reactor.
［従来の技術］
沸騰水型原子炉の制御棒において、現在用いられている
中性子吸収棒は、長尺細径の被覆管内に中性子吸収材と
しての炭化ホウ素（８４Ｇ）粉末を撮動充填して構成さ
れている。しかしながら、８４ Ｃ粉末は中性子照射量
の増加とともに、Ｈｅガス発生による体積膨張を起こし
て被覆管に過大な応力ひずみを加えるため、被覆管にク
ラックが発生して中性子吸収棒の機械的寿命を短くして
いる。[Prior Art] The neutron absorption rods currently used in the control rods of boiling water reactors are made by filling boron carbide (84G) powder as a neutron absorbing material into a long and narrow cladding tube. It is configured. However, as the amount of neutron irradiation increases, 84C powder causes volume expansion due to He gas generation and applies excessive stress and strain to the cladding tube, which causes cracks in the cladding tube and shortens the mechanical life of the neutron absorption rod. are doing.
そこで、８４ Ｃ粉末を成形加工して円柱状ペレットと
し、これを被覆管内に積層して充填することによって、
８４ Ｇと被覆管との機械的相互作用を減じ、中性子吸
収棒の機械的寿命を長くするという提案がなされたく例
えば特開昭５９−２０８４９３号）。この制御棒は、Ｂ
ａ Ｃペレットの外径を中性子照射による体積膨張分を
見込んで被覆管内径より小ざくし、被覆管と８４ Ｃペ
レットの間にギャップ空隙を設けることによって、被覆
管に過大な応力ひずみが加わることを防いでいる。Therefore, by molding 84C powder into cylindrical pellets and stacking them into a cladding tube,
A proposal has been made to reduce the mechanical interaction between the 84 G and the cladding tube and to extend the mechanical life of the neutron absorbing rod (for example, Japanese Patent Laid-Open No. 59-208493). This control rod is B
a Excessive stress and strain will be applied to the cladding tube by making the outer diameter of the C pellet smaller than the inner diameter of the cladding tube to account for volume expansion due to neutron irradiation and creating a gap between the cladding tube and the 84C pellet. is prevented.
しかしながら、この８４ Ｇベレット入り中性子吸収棒
を現用のＢａ Ｃ粉末入り中性子吸収棒と同等の中性子
吸収能力を有するようにし、かつ経済性を維持するため
には、中性子吸収棒の直径ギャップの寸法は最大３００
μｍが限度であった。そして直径ギャップの寸法を３０
０μｍとした場合、８４ Ｇペレット入り中性子吸収棒
の機械的寿命は現在用いられている中性子吸収棒の約１
．２倍に伸びるが、それ以上伸長化することは期待でき
なかった。However, in order to make this neutron absorption rod containing 84 G pellets have the same neutron absorption capacity as the current neutron absorption rod containing Ba C powder and to maintain economic efficiency, the size of the diameter gap of the neutron absorption rod must be Maximum 300
The limit was μm. and the diameter gap dimension is 30
When the diameter is 0 μm, the mechanical life of a neutron absorption rod containing 84 G pellets is about 1
．． Although it has doubled in size, we could not expect it to grow any further.
［発明が解決しようとする問題点］
上記のＢ４Ｃペレット入り中性子吸収棒では、現用中性
子吸収棒の寿命の約１．２倍以上にわたって長期間使用
すると、８４ Ｃベレットの体積膨張で直径ギャップが
閉塞されてＢａ Ｃペレットと被覆管との間で機械的相
互作用が起こり、被覆管に過大な応力ひずみが発生する
という問題があった。[Problems to be solved by the invention] When the above-mentioned neutron absorption rod containing B4C pellets is used for a long period of time, which is approximately 1.2 times longer than the life of the currently used neutron absorption rod, the diameter gap closes due to the volume expansion of the 84C pellet. There was a problem in that mechanical interaction occurred between the Ba C pellet and the cladding tube, resulting in excessive stress and strain in the cladding tube.
また、近年、原子炉の利用率向上をはかるため運転サイ
クルが長期化する傾向があり、現用中性子吸収棒の寿命
の約１６５倍以上の核的寿命の長い中性子吸収棒が要求
されているので、上記の中性子吸収棒ではこれに対応で
きないという゛問題があった。In addition, in recent years, there has been a trend towards longer operating cycles in order to improve the utilization rate of nuclear reactors, and there is a demand for neutron absorption rods with a long nuclear life of approximately 165 times longer than the lifespan of current neutron absorption rods. There was a problem in that the above-mentioned neutron absorption rods could not cope with this problem.
本発明は、上記従来技術の問題点を解決したもので、Ｂ
ａ Ｃと被覆管との機械的相互作用をなくし、しかも原
子炉運転サイクルの長期化に対応できる機械的および核
的寿命の長い中性子吸収棒を提供することを目的とする
ものである。The present invention solves the problems of the prior art described above.
The object of the present invention is to provide a neutron absorption rod that eliminates mechanical interaction between the aC and the cladding tube, and has a long mechanical and nuclear life that can correspond to a prolonged nuclear reactor operating cycle.
［問題点を解決するための手段］
上記目的は、被覆管内に中性子吸収材を充填した中性子
吸収棒において、該中性子吸収材がＢａ Ｃによって形
成された中空円筒状のペレットからなる積層吸収体と該
円筒状ペレットの中空部に配設された棒状ハフニウムと
で構成することにより達成される。[Means for Solving the Problems] The above object is to provide a neutron absorbing rod in which a neutron absorbing material is filled in a cladding tube, in which the neutron absorbing material is a laminated absorber consisting of hollow cylindrical pellets formed of BaC. This is achieved by constructing the cylindrical pellet with a rod-shaped hafnium disposed in the hollow part of the cylindrical pellet.
［作 用］
本発明によって構成された中性子吸収棒では、まず、被
覆管内に装填した８４ Ｃペレットが、従来のＢ４Ｃペ
レットと異なり中空円筒状であって中央部が空洞になっ
ていることから、Ｂａ Ｃの体積膨張が従来より少なく
、Ｂａ Ｃペレットの外径増加が抑えられる。したがっ
て、Ｂａ Ｃペレットと被覆管との間に設けられた直径
ギャップの空隙空間によって８４ Ｃベレットの外径増
加を十分に吸収することができるため、Ｂａ Ｃベレッ
トと被覆管との機械的相互作用をなくして中性子吸収棒
の機械的寿命を長くすることが可能となる。また、中空
円筒状の８４ Ｃベレットの中空部に配置された棒状ハ
フニウムは、中性子を吸収して連鎖的に生成される核種
がそれぞれ大きな中性子吸収断面積を持つことから、ハ
フニウムの中性子吸収能力が長期にわたって維持される
ので中性子吸収棒の核的寿命を艮くすることができる。[Function] First, in the neutron absorption rod constructed according to the present invention, the 84C pellet loaded in the cladding tube is different from the conventional B4C pellet and has a hollow cylindrical shape with a hollow center. The volumetric expansion of Ba C is smaller than before, and an increase in the outer diameter of the Ba C pellets can be suppressed. Therefore, the increase in the outer diameter of the 84C pellet can be sufficiently absorbed by the void space of the diameter gap provided between the Ba C pellet and the cladding tube, so that the mechanical interaction between the Ba C pellet and the cladding tube is reduced. By eliminating this, it becomes possible to extend the mechanical life of the neutron absorption rod. In addition, the rod-shaped hafnium placed in the hollow part of the hollow cylindrical 84C pellet absorbs neutrons and the nuclides that are generated in a chain manner each have a large neutron absorption cross section, so the neutron absorption capacity of hafnium is Since it is maintained over a long period of time, the nuclear lifetime of the neutron absorbing rod can be significantly reduced.
［実施例］ 以下、本発明の実施例を図面を参照しながら説明する。[Example] Embodiments of the present invention will be described below with reference to the drawings.
第１図は未発明の一実施例を示すもので、（ａ）は細径
長尺のステンレスｌｌＩ製被覆管１の内部に中空円筒状
のＢａ Ｃペレット２を積層配置し、Ｂ４Ｃペレットの
中空部に棒状ハフニウム３を配置した中性子吸収棒の縦
断面図であり、（ｂ）はその横断面図である。FIG. 1 shows an embodiment of the invention, in which (a) hollow cylindrical Ba C pellets 2 are stacked and arranged inside a thin and long stainless steel III cladding tube 1; FIG. 3B is a longitudinal cross-sectional view of a neutron absorption rod in which rod-shaped hafnium 3 is arranged in the section, and FIG.
このように構成された本実施例の中性子吸収棒では、中
性子吸収作用は次のようになる。中空円筒状のＢａ Ｃ
ペレットと棒状ハフニウムとからなる中性子吸収体のう
ち、外側に配置されたＢａ Ｃ内包により体積膨張する
が、Ｂａ Ｃベレットが中空円筒状であるためＢａ Ｃ
の伍が少ないので、中性子照射量が増大すると１０ｓの
消耗が早く進んで８４ Ｃベレットの体積膨張すなわち
外径増加が飽和して一定値をとるようになる。したがっ
て、ＢａＣペレットと被覆管との間にこの一定値に達し
た外径増加分に見合った直径ギャップを設ければ、８４
Ｃベレットと被覆管との機械的相互作用の発生を防止
することができる。高い中性子照射量をうけて８４０ペ
レツトの中性子吸収能力が低下すると、中性子吸収体の
内側に配置されたハフニウムが中性子を吸収する。ハフ
ニウムは大きな中性子吸収能力を有する同位体が存在す
るため、中性子吸収棒の中性子吸収能力すなわち核的寿
命は長期にわたって維持されるようになる。In the neutron absorption rod of this embodiment configured in this way, the neutron absorption action is as follows. Hollow cylindrical Ba C
A neutron absorber consisting of a pellet and rod-shaped hafnium expands in volume due to the Ba C inclusions placed on the outside, but since the Ba C pellet is hollow and cylindrical, the Ba C
Since the amount of neutron irradiation increases, the consumption of 10 seconds progresses quickly, and the volume expansion of the 84C pellet, that is, the increase in the outer diameter, becomes saturated and takes a constant value. Therefore, if a diameter gap is provided between the BaC pellet and the cladding tube that corresponds to the increase in the outer diameter that has reached a certain value, 84
Mechanical interaction between the C pellet and the cladding tube can be prevented from occurring. When the neutron absorption capacity of the 840 pellet decreases due to high neutron irradiation, the hafnium placed inside the neutron absorber absorbs the neutrons. Since there are isotopes of hafnium that have a large neutron absorption capacity, the neutron absorption capacity of the neutron absorption rod, that is, the nuclear lifetime, is maintained over a long period of time.
第２図に本実施例における中空円筒状のＢａ Ｃペレッ
トとハフニウムの比率に対する中性子吸収棒の寿命を示
す。現用中性子吸収棒の約１．５倍以上の寿命を有する
ためには、中性子吸収体に占める比率は中空円筒状のＢ
ａ Ｃペレットが約８０％以下で、棒状ハフニウムが約
２０％以上であれば適していることがわかる。中性子吸
収体を１００％棒状ハフニウムとすると、中性子吸収棒
の寿命は約３倍になるが、ハフニウムの比重が大きいこ
とから中性子吸収棒の重量増加が著しくなって好ましく
ない。FIG. 2 shows the life of the neutron absorption rod in this example with respect to the ratio of the hollow cylindrical Ba C pellet and hafnium. In order to have a lifespan approximately 1.5 times longer than that of the current neutron absorption rod, the proportion of the neutron absorber must be hollow cylindrical B.
It can be seen that it is suitable if the aC pellet content is about 80% or less and the rod-shaped hafnium content is about 20% or more. If the neutron absorber is made of 100% rod-shaped hafnium, the life of the neutron absorbing rod will be approximately tripled, but since the specific gravity of hafnium is large, the weight of the neutron absorbing rod will increase significantly, which is not preferable.
以上説明したように、本実施例によれば８４ Ｃと被覆
管との機械的相互作用をなくして中性子吸収棒の機械的
および核的寿命を長くでき、また中性子吸収棒の寿命を
現用中性子吸収棒の約１．５倍以上に容易に伸長化する
ことができる。As explained above, according to this embodiment, the mechanical and nuclear life of the neutron absorption rod can be extended by eliminating the mechanical interaction between 84 C and the cladding tube, and the life of the neutron absorption rod can be extended compared to the current neutron absorption It can be easily extended to about 1.5 times the length of the rod.
［発明の効果コ
本発明によれば、中性子吸収棒の機械的および核的寿命
を長くすることができるので、健全性・経済性の高い中
性子吸収棒を提供できる。また、現用中性子吸収棒の寿
命の約１．５倍以上の長寿命化が容易にできるので、原
子炉運転サイクルの長期化に対応した中性子吸収棒を提
供できる効果がある。[Effects of the Invention] According to the present invention, the mechanical and nuclear life of the neutron absorption rod can be extended, so that a neutron absorption rod with high soundness and economic efficiency can be provided. Furthermore, since the life of the neutron absorption rods in use can be easily extended by about 1.5 times or more, it is possible to provide a neutron absorption rod that can cope with a longer nuclear reactor operation cycle.
第１図は本発明の一実施例の中性子吸収棒の縦断面図と
横断面図、第２図は８４ Ｃペレットとハフニウムとの
比率と中性子吸収棒の寿命との関係を示すグラフである
。
１・・・被覆管
２・・・中空円筒状Ｂ４ Ｃペレット
３・・・ハフニウム
４・・・端栓
（８７３３）代理人 弁理士 猪 股 祥 晃（ばか
１名）
（ａ）
第１図
１００゜
８４Ｃベレツト（０ん）
第２図FIG. 1 is a vertical cross-sectional view and a cross-sectional view of a neutron absorption rod according to an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the ratio of 84 C pellets to hafnium and the life of the neutron absorption rod. 1...Claying tube 2...Hollow cylindrical B4 C pellet 3...Hafnium 4...End plug (8733) Agent Patent attorney Yoshiaki Inomata (Idiot)
1 person) (a) Fig. 1 100°84C Berets (0n) Fig. 2
Claims (2)
において、該中性子吸収材が、炭化ホウ素によつて形成
された中空円筒状のペレットからなる積層吸収体と該ペ
レットの中空部に配設された棒状ハフニウムとで構成さ
れていることを特徴とする中性子吸収棒。(1) In a neutron absorption rod whose cladding tube is filled with a neutron absorption material, the neutron absorption material is arranged in a laminated absorber made of hollow cylindrical pellets made of boron carbide and in the hollow part of the pellets. A neutron absorbing rod characterized by being composed of rod-shaped hafnium.
重量％以上である特許請求の範囲第１項記載の中性子吸
収棒。(2) Rod-shaped hafnium is 20% of the total amount of neutron absorbing material.
% or more by weight of the neutron absorbing rod according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62035868A JPS63205596A (en) | 1987-02-20 | 1987-02-20 | Neutron absorbing rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62035868A JPS63205596A (en) | 1987-02-20 | 1987-02-20 | Neutron absorbing rod |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63205596A true JPS63205596A (en) | 1988-08-25 |
Family
ID=12453967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62035868A Pending JPS63205596A (en) | 1987-02-20 | 1987-02-20 | Neutron absorbing rod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63205596A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103985420A (en) * | 2014-06-05 | 2014-08-13 | 西南科技大学 | Control rod capable of flattening axial power distribution of reactor core and control rod assembly |
-
1987
- 1987-02-20 JP JP62035868A patent/JPS63205596A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103985420A (en) * | 2014-06-05 | 2014-08-13 | 西南科技大学 | Control rod capable of flattening axial power distribution of reactor core and control rod assembly |
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