JPS6035031B2 - fuel assembly - Google Patents
fuel assemblyInfo
- Publication number
- JPS6035031B2 JPS6035031B2 JP53025987A JP2598778A JPS6035031B2 JP S6035031 B2 JPS6035031 B2 JP S6035031B2 JP 53025987 A JP53025987 A JP 53025987A JP 2598778 A JP2598778 A JP 2598778A JP S6035031 B2 JPS6035031 B2 JP S6035031B2
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- fuel assembly
- added
- rods
- power distribution
- 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
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
-
- 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】
本発明は沸騰水型原子炉の燃料集合体に係り、特に軸方
向出力分布を平坦化させる技術に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel assembly for a boiling water nuclear reactor, and particularly to a technique for flattening the axial power distribution.
従来、原子炉の鞠方向出力分布を平坦化するには、軸方
向に核分裂性物質の量を分布させる（例えばＵ凶５の濃
縮度を軸方向に分布させる）と良いといわれている。Conventionally, it has been said that in order to flatten the power distribution of a nuclear reactor in the vertical direction, it is good to distribute the amount of fissile material in the axial direction (for example, distribute the enrichment level of U-5 in the axial direction).
しかし、この方法では、例えば、炉心初期の髄方向出力
分布を平坦化する様にＵ幻５を軸方向に分布させた場合
、炉心末期の軸方向出力分布は上部でピークを有する分
布になり、炉心の全期間を通して、軸方向出力分布を平
坦化することができない。However, in this method, for example, if U illusion 5 is distributed in the axial direction so as to flatten the power distribution in the axial direction at the early stage of the core, the axial power distribution at the end of the core will be a distribution that has a peak at the top. It is not possible to flatten the axial power distribution throughout the life of the core.
すなわち、沸騰水型原子炉ではボィド率は一般に炉心上
部にゆくにつれて大きくなる。That is, in a boiling water reactor, the void fraction generally increases toward the upper part of the reactor core.
ボィド率が大きくなるとＵ２３８に吸収される中性子が
多くなる。中性子を吸収したＵ郷はＰび３９に変化する
ので、Ｕ２３５と同様に核分裂を起し易いＰＵ２斑が多
くなることになる。一方、ボィド率が高くなるとＵ幻５
と中性子の反応数が減り、原子炉運転によるＵ２３５の
減少は遅くなる。As the void ratio increases, more neutrons are absorbed by U238. Since U2 that has absorbed neutrons changes to P239, there will be more PU2 spots that are susceptible to nuclear fission like U235. On the other hand, when the void rate increases, U illusion 5
The number of neutron reactions decreases, and the decrease in U235 due to reactor operation slows down.
この結果、炉心末期では、ボィド率が高い炉心上部では
核分裂性物質の量が多くなり、出力分布は炉心上部で大
きくなる。また、炉心上部で出力が大きくなると、制御
棒は下から入るために、制御榛挿入による原子炉緊急停
止が遅れることになる。本発明は上述の事情を考慮して
なされたもので、燃料集合体の軸方向出力分布を平坦化
し、かつ、原子炉運転上の制限となる線出力密度を低下
させて燃料の健全性を高めることを目的としている。As a result, at the end of the core, the amount of fissile material increases in the upper part of the core where the void ratio is high, and the power distribution becomes larger in the upper part of the core. Furthermore, when the power increases in the upper part of the reactor core, the control rods enter from the bottom, which delays the emergency shutdown of the reactor by inserting the control rods. The present invention has been made in consideration of the above-mentioned circumstances, and improves the soundness of the fuel by flattening the axial power distribution of the fuel assembly and reducing the linear power density, which is a restriction on reactor operation. The purpose is to
以下図面を参照して本発明の一実施例を説明する。An embodiment of the present invention will be described below with reference to the drawings.
第１図は本発明の燃料集合体の一実施例を示す一部破断
斜視図、第２図は本発明の燃料集合体積断面図である。FIG. 1 is a partially cutaway perspective view showing an embodiment of the fuel assembly of the present invention, and FIG. 2 is a volume sectional view of the fuel assembly of the present invention.
燃料集合体は複数本の燃料綾１をスベーサ２で束ね、上
下のタイプレート３，４で固定した燃料東をチャンネル
ボックス５に挿入して構成する。燃料集合体を構成する
燃料棒のうち幾本かはＧら０３を含んでおり、また、該
燃料物質の代りに水が入っているウオーターロッド１０
が存在する。第１図の燃料集合体の上部日，のボィド率
は約６０％、下部日２のボイド率は約３０％である。沸
騰水型原子炉の燃料集合体では、チャンネルボックス５
外に多量の水が存在することが、製造をむずかしくして
いる。The fuel assembly is constructed by bundling a plurality of fuel strands 1 with a spacer 2, and inserting the fuel strands fixed by upper and lower tie plates 3 and 4 into a channel box 5. Some of the fuel rods constituting the fuel assembly contain G03, and water rods 10 contain water instead of the fuel material.
exists. The void fraction in the upper part of the fuel assembly in FIG. 1 is about 60%, and the void ratio in the lower part 2 is about 30%. In the fuel assembly of a boiling water reactor, channel box 5
The presence of large amounts of water outside makes production difficult.
すなわち、どの燃料綾も等しい量のＵ聡を含んでいるな
らばウオーターギャップ（炉心に装荷された燃料集合体
の制御榛に面しない側）に面した燃料榛の出力は平均的
出力１（以下、出力は平均出力に対する相対値で表わす
。）として、約１．３と非常に大きな値になる。それ故
、燃料集合体内の出力分布をあまり大きくせず、しかも
、ボィド率が等しい場合には、燃料集合体上部の無限増
倍係数ｋのが、下部のｋのより大きくなるように燃料棒
を配列する必要がある。そのためには、Ｇ４０３を含ん
だ燃料棒が次の条件を満足すればよい。In other words, if all fuel strands contain the same amount of U-S, the output of the fuel strand facing the water gap (the side of the fuel assembly loaded in the core that does not face the control ridge) will be the average output 1 (less than , the output is expressed as a relative value to the average output), which is a very large value of about 1.3. Therefore, if the power distribution within the fuel assembly is not made too large and the void fraction is the same, the fuel rods should be arranged so that the infinite multiplication coefficient k in the upper part of the fuel assembly is larger than that in the lower part. need to be arrayed. For this purpose, the fuel rod containing G403 only needs to satisfy the following conditions.
すなわち、燃料榛上部の核分裂怪物質量＞燃料榛下部の
核分裂性物質量燃料綾上部のＧｄ２０３の量＜燃料榛下
部のＧも０３の量という条件を満足すればよい。That is, the condition that the fission monster mass in the upper part of the fuel ridge>the amount of fissile material in the lower part of the fuel ridge>the amount of Gd203 in the upper part of the fuel ridge<the amount of G in the lower part of the fuel ridge should also be satisfied.
第３図イは本発明の燃料集合体に配列される燃料棒の種
類、第３図口はその配列の一実施例を示す説明図である
。FIG. 3A is an explanatory diagram showing the types of fuel rods arranged in the fuel assembly of the present invention, and the opening in FIG. 3 shows an example of the arrangement.
Ａ，Ｂ，Ｃ，Ｄ，ＥはＧも０３を含まない燃料棒で核燃
料物質は一様に分布している。Ｆ‘ま○４０３を含む燃
料棒で、上部と下部で核分裂性物質およびＧ中０３の量
を異にする。Ｗはウオーターロッドを示す。このような
、燃料榛の配列をすると、Ｇも０３を含む燃料棒の本数
が少くてすみ、かつ、燃料集合体の軸方向出力分布を平
坦化できる。第４図は、拡散コードで計算した燃料集合
体出力分布を示す説明図である。A, B, C, D, and E are fuel rods that do not contain G or 03, and the nuclear fuel material is uniformly distributed. A fuel rod containing F'Ma○403, with different amounts of fissile material and G03 in the upper and lower parts. W indicates a water rod. By arranging the fuel rods in this manner, the number of fuel rods including G03 can be reduced, and the axial power distribution of the fuel assembly can be flattened. FIG. 4 is an explanatory diagram showing the fuel assembly power distribution calculated using the diffusion code.
燃料棒の出力は第３図Ｗ−Ｗ線に対して対称であり、第
４図は半分のみ示してある。第４図イは、燃料集合体上
部の出力分布、口は下部の出力分布である。燃料集合体
上部ボィド率６０％において局所最大出力は１．１ふｋ
の＝１．１０１、燃料集合体下部ボィド率３０％におい
て局所最大出力１．１６、ｋの＝１．１０１であり、水
平方向の最大出力は１．１５〜１．１６と小さく、且つ
、鞠方向は無限増倍係数ｋのはほとんど同じ値であり、
軸方向出力は平坦になる。The power output of the fuel rods is symmetrical with respect to line W--W in FIG. 3, and only half is shown in FIG. Figure 4A shows the power distribution in the upper part of the fuel assembly, and the figure shows the power distribution in the lower part. Local maximum output is 1.1 fk when fuel assembly upper void ratio is 60%
= 1.101, the local maximum output is 1.16 at the fuel assembly lower void ratio of 30%, and the maximum output in the horizontal direction is small at 1.15 to 1.16. In the direction, the infinite multiplication coefficient k has almost the same value,
The axial output becomes flat.
沸騰水型原子炉においては、ボィドが下から発生し、上
に行くにつれてボイド量が多くなる。ボィドが発生する
と中性子の減速材としての水が減少する。一方Ｕ２３５
は減速された中性子により敏感に核分裂を起す。上述の
二事象により、燃料集合体中のＵ２時の量を軸万向に一
様にした場合は、軸方向出力分布は上方で小さく、下方
で大きな出力になる。In a boiling water reactor, voids occur from the bottom, and the amount of voids increases as you go up. When voids occur, water, which acts as a moderator for neutrons, decreases. On the other hand, U235
is sensitive to nuclear fission due to decelerated neutrons. Due to the above two events, if the amount of U2 in the fuel assembly is made uniform in all axial directions, the axial power distribution will be small in the upper part and large in the lower part.
従って、燃料集合体上部のＵ２３５の濃縮度を高くすれ
ば、軸万向出力は平坦化される。一方、Ｇも０３は中性
子を吸収する作用が強いのでＧｄ２０３がある場所では
中性子東が小さくなり、該分裂の回数も減少する。Therefore, by increasing the enrichment of U235 in the upper part of the fuel assembly, the output in all directions of the shaft can be flattened. On the other hand, G03 also has a strong effect of absorbing neutrons, so where Gd203 is present, the neutron east becomes smaller and the number of times of this splitting also decreases.
従って、燃料集合体上部のＧｄ２０３の量を少くし、下
部のＧｄ２Ｑの量を大きくすることによっても燃料集合
体麹方向出力分布を平坦化できる。Ｇも０３を含む燃料
棒のＵ２３５の濃縮度に燃料綾上部と下部で差をつけて
も、Ｇも０３の中性子吸収により、その燃料綾の出力は
極端に小さくなり、Ｇら０３が中性子吸収能力を有して
いる炉心初期においては、燃料集合体の軸方向出力分布
には大きな影響を与えない。Therefore, the fuel assembly koji direction output distribution can also be flattened by reducing the amount of Gd203 in the upper part of the fuel assembly and increasing the amount of Gd2Q in the lower part. Even if the U235 enrichment of the fuel rod containing G03 is made different between the upper and lower part of the fuel shaft, the output of that fuel shaft will be extremely small due to the absorption of neutrons by G03, In the early stage of the reactor core, when it has the capacity, it does not have a large effect on the axial power distribution of the fuel assembly.
沸騰水型原子炉で燃料にＧｄ２０３を加えるのは、Ｕ紙
を多く装荷して取得燃料度を増すためである。The reason why Gd203 is added to the fuel in a boiling water reactor is to increase the amount of fuel obtained by loading a large amount of U paper.
すなわち、Ｕ２３５を多量に装荷することによる初期余
剰反応反応度の増加分をＧｄ２０３により補償し、炉心
初期の原子炉を制御棒で安全に停止させるためである。
一方、Ｇ■０３は一度中性子を吸収すると、中性子吸収
能力が極端に低下するので、Ｇｄ２０３を加えた燃料で
は、炉心末期に反応度不足を起さない。That is, this is to compensate for the increase in initial surplus reaction reactivity due to loading a large amount of U235 with Gd203, and to safely stop the reactor at the initial stage of the core using the control rods.
On the other hand, once Gd203 absorbs neutrons, its neutron absorption capacity is extremely reduced, so fuel with Gd203 added will not cause insufficient reactivity at the end of the core.
かくして、炉心初期ではＵ凶５とＧｄ２０３の軸方向分
布で燃料集合体の軸方向出力分布を平坦化させ、炉心末
期にはＵ瓶のみの鞠方向分布で燃料集合体の軸方向出力
分布を平坦化させる。また、Ｕ凶５濃度に分布があるの
は、Ｇｄ２０３入りの燃料棒のみであり、第４図に示す
ように、燃料集合体の出力分布は、Ｇｄ２０３入りの燃
料棒を除し、て、上部と下部でほとんど同じ値であり、
燃料のスプリット配置が簡明になる。Thus, at the early stage of the core, the axial distribution of U5 and Gd203 flattens the axial power distribution of the fuel assembly, and at the end of the core, the axial distribution of only the U bottle flattens the axial power distribution of the fuel assembly. to become Furthermore, only the fuel rods containing Gd203 have a distribution in the U-5 concentration, and as shown in Figure 4, the power distribution of the fuel assembly is as follows, excluding the fuel rods containing Gd203, and are almost the same value at the bottom,
The fuel split arrangement becomes simple.
以上説明したように、本発明の燃料集合体によれば、炉
心の全期間を通して、燃料集合体の軸万向出力分布は平
坦化され、かつ、局所最大出力の平均値からのずれも小
さく、健全性の高い炉心が得られる。As explained above, according to the fuel assembly of the present invention, the power distribution in all axial directions of the fuel assembly is flattened throughout the entire period of the reactor core, and the deviation of the local maximum power from the average value is also small. A highly sound core can be obtained.
また、本発明の燃料集合体は、上下でＵ２＄およびＧも
０３の濃度が異なる燃料棒の数が少ないので、燃料集合
体の製造が容易になる。Further, since the fuel assembly of the present invention has a small number of fuel rods in which the U2$ and G03 concentrations differ between the upper and lower portions, the fuel assembly can be manufactured easily.
第５図は、本発明の他の実施例を示す説明図である。FIG. 5 is an explanatory diagram showing another embodiment of the present invention.
第５図イは燃料棒の種類を、口は燃料榛の配列を示す。
この場合、Ｇも０３入りの燃料榛はＦ，，Ｆ２の二種類
である。また、ＧＱ０３入りの燃料棒はウオーターギャ
ップに近い所に配置されており、この場合、ウオーター
ギャップで発生した熱中性子をより多く吸収するので、
第３図に示した燃料綾配列に比較して、ｋのは増加する
。すなわち、燃料集合体上部において、ボィド率６０％
のとき、局所最大出力１．１１４、ｋのコ１．１０燃料
集合体下部において、ボィド率３０％のとき、局所最大
出力１．１５３ ｋの＝１．１６である。Figure 5A shows the types of fuel rods, and the ports show the arrangement of the fuel rods.
In this case, there are two types of fuel rods containing G and 03: F, and F2. In addition, the fuel rod containing GQ03 is placed close to the water gap, and in this case, it absorbs more thermal neutrons generated in the water gap.
Compared to the fuel tread arrangement shown in FIG. 3, k is increased. In other words, in the upper part of the fuel assembly, the void ratio is 60%.
When the local maximum output is 1.114, k = 1.10 at the bottom of the fuel assembly, when the void ratio is 30%, the local maximum output is 1.153, k = 1.16.
第１図は本発明の燃料集合体の一実施例を示す一部破断
斜視図、第２図は本発明の燃料集合体積断面図、第３図
は本発明の燃料集合体の燃料榛配列の一実施例を示す説
明図、第４図は本発明の燃料集合体一実施例における出
力分布を示す説明図、第５図は本発明の燃料集合体の燃
料榛配列の他の実施例を示す説明図である。
１・…・・燃料榛、５・・・・・・チャンネルボックス
、１０”““ウオーターロツド。
第１図
第２図
第３図
第４図
第５図FIG. 1 is a partially cutaway perspective view showing an embodiment of the fuel assembly of the present invention, FIG. 2 is a volumetric cross-sectional view of the fuel assembly of the present invention, and FIG. 3 is a fuel comb arrangement of the fuel assembly of the present invention. FIG. 4 is an explanatory diagram showing an embodiment of the fuel assembly of the present invention. FIG. 5 is an explanatory diagram showing the power distribution in one embodiment of the fuel assembly of the present invention. FIG. It is an explanatory diagram. 1...Fuel rod, 5...Channel box, 10"""Water rod. Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5
Claims (1)
で固定した燃料束をチヤンネルボツクスに挿入して構成
される燃料集合体において、幾本かの燃料棒にはＧｄ＿
２Ｏ＿３が添加されており、前記Ｇｄ＿２Ｏ＿３を添加
した燃料棒においては、燃料棒上部の核分裂性物質の濃
度が燃料棒下部の核分裂性物質の濃度より多く、かつ、
燃料棒上部に添加されたＧｄ＿２Ｏ＿３の濃度は燃料棒
下部に添加されたＧｄ＿２Ｏ＿３の濃度より少いことを
特徴とする燃料集合体。 ２ 燃料集合体を構成している燃料棒の中で、Ｇｄ＿２
Ｏ＿３を添加した燃料棒に含まれる核分裂生成物濃度は
最低であることを特徴とする特許請求の範囲第１項記載
の燃料集合体。 ３ 下部にＧｄ＿２Ｏ＿３を添加した燃料棒をウオータ
ーギヤツプの近くに配置し、上部にＧｄ＿２Ｏ＿３を添
加した燃料棒を燃料集合体中央部に配置したことを特徴
とすることを特徴とする特許請求の範囲第１項記載の燃
料集合体。[Claims] 1. In a fuel assembly constructed by inserting a fuel bundle in which a plurality of fuel rods are bundled with spacers and fixed by upper and lower tie plates into a channel box, some of the fuel rods have Gd_
2O_3 is added, and in the fuel rod to which Gd_2O_3 is added, the concentration of fissile material in the upper part of the fuel rod is higher than the concentration of fissile material in the lower part of the fuel rod, and
A fuel assembly characterized in that the concentration of Gd_2O_3 added to the upper part of the fuel rod is lower than the concentration of Gd_2O_3 added to the lower part of the fuel rod. 2 Among the fuel rods that make up the fuel assembly, Gd_2
2. The fuel assembly according to claim 1, wherein the concentration of fission products contained in the fuel rod to which O_3 is added is the lowest. 3. The fuel rod with Gd_2O_3 added to the lower part is arranged near the water gap, and the fuel rod with Gd_2O_3 added to the upper part is arranged in the center of the fuel assembly. A fuel assembly according to scope 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP53025987A JPS6035031B2 (en) | 1978-03-09 | 1978-03-09 | fuel assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP53025987A JPS6035031B2 (en) | 1978-03-09 | 1978-03-09 | fuel assembly |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54118978A JPS54118978A (en) | 1979-09-14 |
| JPS6035031B2 true JPS6035031B2 (en) | 1985-08-12 |
Family
ID=12181052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP53025987A Expired JPS6035031B2 (en) | 1978-03-09 | 1978-03-09 | fuel assembly |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6035031B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02106575U (en) * | 1989-02-10 | 1990-08-24 | ||
| US11257232B2 (en) | 2017-05-08 | 2022-02-22 | University Of Fukui | Three-dimensional measurement method using feature amounts and device using the method |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56157890A (en) * | 1980-05-08 | 1981-12-05 | Tokyo Shibaura Electric Co | Boiling type atomic reactor |
| JPS5784388A (en) * | 1980-11-14 | 1982-05-26 | Nippon Atomic Ind Group Co | Fuel assembly |
| JPS60242392A (en) * | 1984-05-16 | 1985-12-02 | 株式会社日立製作所 | Fuel aggregate |
-
1978
- 1978-03-09 JP JP53025987A patent/JPS6035031B2/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02106575U (en) * | 1989-02-10 | 1990-08-24 | ||
| US11257232B2 (en) | 2017-05-08 | 2022-02-22 | University Of Fukui | Three-dimensional measurement method using feature amounts and device using the method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54118978A (en) | 1979-09-14 |
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