JPH048759B2 - - Google Patents
Info
- Publication number
- JPH048759B2 JPH048759B2 JP56047505A JP4750581A JPH048759B2 JP H048759 B2 JPH048759 B2 JP H048759B2 JP 56047505 A JP56047505 A JP 56047505A JP 4750581 A JP4750581 A JP 4750581A JP H048759 B2 JPH048759 B2 JP H048759B2
- Authority
- JP
- Japan
- Prior art keywords
- rods
- rod
- control rod
- absorption
- neutron
- 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)
Description
【発明の詳細な説明】 本発明は原子炉用制御棒に係る。[Detailed description of the invention] The present invention relates to a control rod for a nuclear reactor.
従来の制御棒は、ウイング内に強度の中性子吸
収を示す中性子吸収棒（以下中性子強吸収棒と呼
ぶ）だけを多数装填して構成されていた。 Conventional control rods are constructed by loading only a large number of neutron absorption rods (hereinafter referred to as strong neutron absorption rods) that exhibit strong neutron absorption in the wings.
ところが、制御棒の使用目的によつては、中性
子強吸収棒のみを装填して成る従来の制御棒より
も、反応度価値が小さい方がよい場合がある。例
えば、原子炉出力調整にしばしば挿抜される制御
棒の場合には、反応度価値が低い方が引抜時の熱
的インパクトが少くてすむ。 However, depending on the intended use of the control rod, it may be better to have a smaller reactivity value than a conventional control rod loaded with only strong neutron absorption rods. For example, in the case of control rods that are often inserted and removed to adjust reactor power, the lower the reactivity value, the less the thermal impact upon removal.
また、制御棒は多量の中性子が照射されるもの
であり、中性子吸収の進行につれ中性子吸収物質
が減損すると交換しなければならない。而して、
使用ずみの制御棒は高度の放射能を帯びているの
で、その保管、処理に多大の費用を必要とする。
従つて、交換をできるだけ少くするため、制御棒
は長寿命型であることが望ましい。 In addition, control rods are irradiated with a large amount of neutrons, and must be replaced if the neutron absorbing material is depleted as neutron absorption progresses. Then,
Used control rods are highly radioactive and require a great deal of expense to store and dispose of.
Therefore, in order to minimize the number of replacements, it is desirable that the control rods have a long life.
長寿命型の制御棒としては、中性子吸収棒とし
てHfメタル棒、Eu2O3混合物を金属管に充填した
もの、Ag−In−Cd合金棒等を使用したものが適
しているが、これらの中性子強吸収棒は高価であ
る。また、比重が大きく制御棒が重くなるため、
制御棒駆動装置を変更する必要がある。 Suitable long-life control rods include Hf metal rods, metal tubes filled with Eu 2 O 3 mixture, and Ag-In-Cd alloy rods as neutron absorption rods. Strong neutron absorption rods are expensive. In addition, because the specific gravity is large and the control rod is heavy,
It is necessary to change the control rod drive.
本発明は上記の事情に基きなされたもので、引
抜時に燃料集合体に与える熱的インパクトが少
く、長寿命でしかも軽量に構成し得、比較的安価
に供給し得る原子炉用制御棒を得ることを目的と
している。 The present invention has been made based on the above circumstances, and provides a control rod for a nuclear reactor that has a small thermal impact on a fuel assembly during extraction, has a long life, can be configured to be lightweight, and can be supplied at a relatively low cost. The purpose is to
本発明においては、前記長寿命型の中性子強吸
収材と中性子吸収性の低い中性子吸収材（以下中
性子弱吸収材という）とを混用して前記目的を達
成している。中性子吸収棒には、例えば公知の中
空SUS管がある。 In the present invention, the above object is achieved by using a combination of the long-life type strong neutron absorber and a neutron absorber with low neutron absorbing property (hereinafter referred to as weak neutron absorber). Examples of neutron absorption rods include known hollow SUS tubes.
本発明は下記の実験の結果得られた知見に基き
なされている。すなわち、中性子強吸収棒のみで
構成した制御棒の反応度価値と、その中の何本か
を中性子弱吸収棒で置換したものの反応度価値と
を測定した所、第１図の曲線で示す結果が得られ
た。第１図において、横軸は中性子吸収棒全数中
に占める中性子強吸収棒の割合（％）、縦軸は全
数が中性子吸収棒である時の反応度価値を１とし
て示す反応度価値である。この図から、反応度価
値は中性子弱吸収棒の割合が増加するにつれ低減
し、前記割合が約50％程度の時、15％程度の低下
となることがわかる。 The present invention is based on the knowledge obtained as a result of the following experiments. In other words, when we measured the reactivity value of a control rod composed only of strong neutron absorption rods and the reactivity value of a control rod in which some of the control rods were replaced with weak neutron absorption rods, we obtained the results shown by the curve in Figure 1. was gotten. In FIG. 1, the horizontal axis is the proportion (%) of strong neutron absorbing rods in the total number of neutron absorbing rods, and the vertical axis is the reactivity value, which is expressed as 1 when all the rods are neutron absorbing rods. From this figure, it can be seen that the reactivity value decreases as the proportion of weak neutron absorbing rods increases, and when the proportion is about 50%, it decreases by about 15%.
本発明は上記の事実を利用したもので、所望の
反応度価値となる割合で中性子弱吸収棒を混用
し、制御棒の軽量化、低価格化をはかつている。 The present invention takes advantage of the above-mentioned fact, and uses weak neutron absorbing rods in combination in a proportion that provides the desired reactivity value, thereby reducing the weight and cost of the control rod.
また、中性子吸収棒が全部吸収棒とされた制御
棒のウイング巾方向の中性子吸収率分布を測定し
たところ、第２図に示す結果が得られた。この図
において、横軸はタイロツドからの距離、縦軸は
吸収率（相対値）を示している。この図からウイ
ング外側縁近傍の３〜５本の吸収棒の吸収率が特
に高いことがわかる。従つて、外側縁近傍に高吸
収棒を密に配置するようにすれば、高吸収棒を少
くしても極端に反応度価値が低下することはな
い。 Furthermore, when the neutron absorption rate distribution in the wing width direction of a control rod in which all neutron absorption rods were made into absorption rods was measured, the results shown in FIG. 2 were obtained. In this figure, the horizontal axis shows the distance from the tie rod, and the vertical axis shows the absorption rate (relative value). From this figure, it can be seen that the absorption rate of 3 to 5 absorption rods near the outer edge of the wing is particularly high. Therefore, if the high-absorption rods are densely arranged near the outer edge, the reactivity value will not drop significantly even if the number of high-absorption rods is reduced.
本発明は上記の事実を利用して、引抜の際に隣
接する燃料集合体に与える熱的インパクトが少
く、しかも軽量に構成し得、安価に供給すること
ができる制御棒を構成したものである。長寿命型
の強中性子吸収材としては前述のようにHf、
Eu2O3、Ag−In−Cdが代表的である。中性子弱
吸収材としては原子炉で充分使用実績のある公知
のステンレス鋼管（比重8.0）、ジルカロイ管（比
重6.5）などが好適である。また、管のみでなく
中実棒でもよい。 The present invention takes advantage of the above facts to construct a control rod that has less thermal impact on adjacent fuel assemblies during extraction, can be constructed lightweight, and can be supplied at low cost. . As mentioned above, Hf,
Typical examples are Eu 2 O 3 and Ag-In-Cd. As the weak neutron absorbing material, well-known stainless steel tubes (specific gravity 8.0), Zircaloy tubes (specific gravity 6.5), etc., which have been sufficiently used in nuclear reactors, are suitable. Moreover, not only a pipe but also a solid rod may be used.
以下、図面につき本発明の詳細を説明する。第
３図は本発明の対象となる制御棒全体の斜視図、
第４図はその横断面図であつて、制御棒は十字状
断面のタイロツド２の各突脚に深いＵ字状断面の
シース３を、それらの開口部において取付けて制
御棒ウイングとし、各ウイング内には中性子吸収
棒４を装填して構成されている。 The invention will be explained in detail below with reference to the drawings. FIG. 3 is a perspective view of the entire control rod that is the object of the present invention;
FIG. 4 is a cross-sectional view of the control rod, in which a sheath 3 with a deep U-shaped cross section is attached to each leg of a tie rod 2 with a cross-shaped cross section at the opening thereof to form a control rod wing. A neutron absorption rod 4 is loaded inside.
本発明においては、第５図において制御棒１の
一つのウイングについて拡大して示すように、ウ
イング外側縁近傍の５本を中性子強吸収棒５と
し、またタイロツド２近傍の２本を中性子弱吸収
棒６とし、またそれらの中間には強吸収棒５、弱
吸収棒６を所定の割合、例えば強吸収棒５と弱吸
収棒６を１対１の割合で交互に配置する。 In the present invention, as shown in an enlarged view of one wing of the control rod 1 in FIG. 5, five rods near the outer edge of the wing are strong neutron absorbing rods 5, and two near the tie rod 2 are weak neutron absorbing rods. A strong absorption rod 5 and a weak absorption rod 6 are alternately arranged in a predetermined ratio, for example, a strong absorption rod 5 and a weak absorption rod 6 at a ratio of 1:1.
上記の如くすれば、比重が大きく高価な中性強
九吸収棒をへらして軽量且つ安価な制御棒として
も、制御棒反応度価値の極端な低下を生じること
はない。すなわち、強、弱吸収棒の割合を選定し
て、引抜時に隣接する燃料集合体に与える熱的イ
ンパクトの小さくなる反応度価値のものとするこ
とができる。 By doing so, even if the control rod is made lighter and cheaper by replacing the expensive neutral strong nine absorption rod with a large specific gravity, the value of the control rod reactivity will not be drastically reduced. That is, the ratio of strong and weak absorption rods can be selected to have a reactivity value that reduces the thermal impact on adjacent fuel assemblies during extraction.
なお、上記の如くした本発明制御棒の引抜時に
おける隣接する燃料集合体の熱的インパクトは次
の通りである。第６図において、燃料集合体７は
８×８バンドルであり、64本の燃料棒８を格子状
に配列してチヤンネルボツクス９内に収容して構
成されている。 The thermal impact on adjacent fuel assemblies during the withdrawal of the control rod of the present invention as described above is as follows. In FIG. 6, the fuel assembly 7 is an 8×8 bundle, and is constructed by arranging 64 fuel rods 8 in a grid pattern and housing them in a channel box 9.
隣接する４箇の燃料集合体の十字状間隙には制
御棒CRが挿抜自在に挿入されている。上記の状
態において、燃料集合体の燃料棒中制御棒CRの
ウイングに直面対向している８1〜８8は、制御棒
が従来の制御棒であれば制御棒CRの挿入時に出
力を大巾におさえられており、従つて引抜時には
大巾に出力が上昇する。特にタイロツド近傍の燃
料棒において前記の出力の抑制、上昇は著しい。
本発明の制御棒においては、タイロツド近傍の中
性子吸収棒は弱吸収棒とされているので、制御棒
挿入時にあつても、燃料棒８1の出力低下はそれ
程大巾ではなく、従つて制御棒引抜時の出力上昇
も大巾ではなく、燃料集合体に与えられる熱的イ
ンパクトは軽減される。 A control rod CR is removably inserted into the cross-shaped gap between four adjacent fuel assemblies. In the above state, among the fuel rods in the fuel assembly, the control rods 8 1 to 8 8 , which face the wing of the control rod CR, have a large output when the control rod CR is inserted, if the control rods are conventional control rods. Therefore, the output increases significantly during extraction. Particularly in the fuel rods near the tie rods, the above-mentioned suppression and increase in output are remarkable.
In the control rod of the present invention, the neutron absorption rod near the tie rod is a weak absorption rod, so even when the control rod is inserted, the decrease in the output of the fuel rod 81 is not so large, and therefore the control rod The increase in output during extraction is not large, and the thermal impact on the fuel assembly is reduced.
第７図は第６図に示した燃料集合体の燃料棒８
１〜８8の制御棒挿入時の出力を示している。この
図において、曲線C1は従来の制御棒を挿入した
時の出力、曲線C2は本発明の制御棒を挿入した
時の出力をそれぞれ示している。 Figure 7 shows the fuel rod 8 of the fuel assembly shown in Figure 6.
It shows the output when control rods 1 to 8 are inserted. In this figure, curve C 1 shows the output when the conventional control rod is inserted, and curve C 2 shows the output when the control rod of the present invention is inserted.
この図からもわかるように、本発明の制御棒を
挿入すれば、従来の制御棒の挿入により最も出力
を抑制されていた燃料棒８1の出力はかなり上昇
し、引抜時の熱的インパクトが減少される。 As can be seen from this figure, when the control rod of the present invention is inserted, the output of fuel rod 81 , whose output was suppressed the most by conventional control rod insertion, increases considerably, and the thermal impact upon withdrawal is reduced. reduced.
以上に述べたように本発明に係る原子炉用制御
棒において、各ウイング内にはウイング外側縁近
傍に長寿命型の中性子吸収材を、タイロツド近傍
に中性子弱吸収材をそれぞれ配設し、その他の中
間部分に上記中性子強吸収材と中性子弱吸収材と
を交互に配置したので、制御棒挿入時にタイロツ
ド側近傍領域の出力低下を抑制してウイング幅方
向の出力低下を平坦化する一方、制御棒引抜時の
局所的な出力上昇を抑制し、燃料集合体に与える
熱的インパクトを著しく効果的に軽減させること
ができる。 As described above, in the control rod for a nuclear reactor according to the present invention, a long-life neutron absorber is provided in each wing near the outer edge of the wing, a weak neutron absorber is provided near the tie rod, and other The strong neutron absorbing material and the weak neutron absorbing material are arranged alternately in the middle part of the control rod, so when the control rod is inserted, the power drop in the area near the tie rod side is suppressed and the power drop in the wing width direction is flattened, while the control It is possible to suppress local power increases during rod withdrawal and to significantly and effectively reduce thermal impact on the fuel assembly.
また、この制御棒は、反応度の低下が小さいの
で、特に大反応度制御棒を用いる必要がなく、制
御棒全体を比較的安価に製造することができ、さ
らに、中性子照射量の多いウイング側側縁近傍に
長寿命型の中性子強吸収材を配置したので、長寿
命化を図ることができ、さらにまた、制御棒全体
を長寿命型強中性子吸収材を配置する必要がない
ので軽量化を図ることができる。 In addition, since this control rod has a small decrease in reactivity, there is no need to use a particularly high reactivity control rod, and the entire control rod can be manufactured at a relatively low cost. Long-life strong neutron absorbers are placed near the side edges, making it possible to extend the life of the control rod.Furthermore, there is no need to place long-life strong neutron absorbers in the entire control rod, resulting in weight reduction. can be achieved.
第１図、第２図は本発明の原理を説明するため
の線図、第３図は本発明一実施例の斜視図、第４
図はその横断面図、第５図は前記実施例要部の拡
大断面図、第６図は制御棒と燃料集合体との関係
を示す模式図、第７図は本発明の一効果を説明す
るための線図である。
２……タイロツド、３……シース、５……中性
子強吸収棒、６……中性子弱吸収棒。
Figures 1 and 2 are diagrams for explaining the principle of the present invention, Figure 3 is a perspective view of an embodiment of the present invention, and Figure 4 is a diagram for explaining the principle of the present invention.
The figure is a cross-sectional view thereof, FIG. 5 is an enlarged sectional view of the main part of the embodiment, FIG. 6 is a schematic diagram showing the relationship between the control rod and the fuel assembly, and FIG. 7 is an explanation of one effect of the present invention. This is a diagram for 2...Tie rod, 3...Sheath, 5...Strong neutron absorption rod, 6...Weak neutron absorption rod.
Claims (1)
字状断面のシースをその開口部においてそれぞれ
取付けて十字状に突出するウイングを構成し、各
ウイング内にはウイング外側縁近傍に長寿命型の
中性子強吸収材を、前記タイロツド近傍には中性
子弱吸収材をそれぞれ配設し、その他の中間部分
に上記中性子強吸収材と中性子弱吸収材とを交互
に配置したことを特徴とする原子炉用制御棒。1 Deep U on each protruding leg of the cross-shaped tie rod
A wing with a cross-shaped cross section is attached to each opening of the sheath, and a long-life strong neutron absorber is installed near the outer edge of the wing, and a weak neutron absorber is installed near the tie rod in each wing. 1. A control rod for a nuclear reactor, characterized in that absorbers are respectively arranged, and the strong neutron absorber and the weak neutron absorber are alternately arranged in the other intermediate portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56047505A JPS57161586A (en) | 1981-03-31 | 1981-03-31 | Nuclear reactor control rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56047505A JPS57161586A (en) | 1981-03-31 | 1981-03-31 | Nuclear reactor control rod |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57161586A JPS57161586A (en) | 1982-10-05 |
| JPH048759B2 true JPH048759B2 (en) | 1992-02-18 |
Family
ID=12776962
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56047505A Granted JPS57161586A (en) | 1981-03-31 | 1981-03-31 | Nuclear reactor control rod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57161586A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI890998A7 (en) * | 1988-04-14 | 1989-10-15 | Gen Electric | Long-life nuclear reactor control rod |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5374697A (en) * | 1976-12-13 | 1978-07-03 | Nippon Atom Ind Group Co Ltd | Control rod |
-
1981
- 1981-03-31 JP JP56047505A patent/JPS57161586A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57161586A (en) | 1982-10-05 |
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