JPS6324194A - Fuel aggregate - Google Patents
Fuel aggregateInfo
- Publication number
- JPS6324194A JPS6324194A JP61167575A JP16757586A JPS6324194A JP S6324194 A JPS6324194 A JP S6324194A JP 61167575 A JP61167575 A JP 61167575A JP 16757586 A JP16757586 A JP 16757586A JP S6324194 A JPS6324194 A JP S6324194A
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- fissile material
- density
- fuel rods
- fuel assembly
- 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
- 239000000446 fuel Substances 0.000 title claims description 72
- 239000000463 material Substances 0.000 claims description 25
- 229910052778 Plutonium Inorganic materials 0.000 claims description 8
- OYEHPCDNVJXUIW-UHFFFAOYSA-N plutonium atom Chemical compound [Pu] OYEHPCDNVJXUIW-UHFFFAOYSA-N 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 4
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 4
- 230000000712 assembly Effects 0.000 description 3
- 238000000429 assembly Methods 0.000 description 3
- JFALSRSLKYAFGM-OIOBTWANSA-N uranium-235 Chemical compound [235U] JFALSRSLKYAFGM-OIOBTWANSA-N 0.000 description 3
- 239000003758 nuclear fuel Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- OYEHPCDNVJXUIW-FTXFMUIASA-N 239Pu Chemical compound [239Pu] OYEHPCDNVJXUIW-FTXFMUIASA-N 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000009377 nuclear transmutation Methods 0.000 description 1
- OYEHPCDNVJXUIW-OIOBTWANSA-N plutonium-241 Chemical compound [241Pu] OYEHPCDNVJXUIW-OIOBTWANSA-N 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 238000000926 separation method Methods 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
- Inert Electrodes (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) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.
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、軽水型原子炉の燃料集合体に係り、特に高転
換型軽水炉の燃料集合体に関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a fuel assembly for a light water reactor, and particularly to a fuel assembly for a high conversion light water reactor.
（従来の技術）
一般にＰＷＲやＢＷＲ等°のいわゆる従来型軽水炉では
、燃料中に含まれるウラン−２３５等の核分裂性物質が
核分裂反応を起こしてエネルギーの放出をすると同時に
中性子を放出し、この放出された中性子の一部は同時に
炉心内に存在しているウラン−２３８等の親物質に吸収
される。(Prior art) In general, in so-called conventional light water reactors such as PWR and BWR, fissile materials such as uranium-235 contained in the fuel cause a fission reaction and release energy, and at the same time emit neutrons. A part of the emitted neutrons is simultaneously absorbed by the parent material such as uranium-238 present in the reactor core.
中性子を吸収した親物質は核変換によりプルトニウム−
２３９等の新たな核分裂性物質に変換される。The parent material that absorbed neutrons becomes plutonium through nuclear transmutation.
It is converted into new fissile materials such as 239.
このようにウラン−２３５等の燃料の消費量に対してウ
ラン−２３８等の親物質の中性子捕獲による新たな核分
裂性物質生成量の比を転換比と呼び、ＢＷＲ等の従来型
軽水炉ではこの転換比は約０．６程度である。In this way, the ratio of the amount of new fissile material produced by capturing neutrons of parent materials such as uranium-238 to the consumption of fuel such as uranium-235 is called the conversion ratio, and in conventional light water reactors such as BWRs, this conversion The ratio is about 0.6.
この転換比を高くして生成された核分裂性プルトニウム
を核燃料として有効利用することは、ウラン資源の有効
利用という観点からも、また核拡散防止上の観点からも
好都合でおる。近年、転換比を０．８〜１．０と高くし
てウラン−２３８をプルトニウムに有効に転換するとと
もに、プルトニウムを有効に利用することが可能な高転
換型軽水炉の開発が行われている。この高転換型軽水炉
では前述した転換比を高めるために炉内の減速材対燃料
の体積比（Ｖｍ／Ｖｆ）を小さくし中性子スペクトラム
を硬くする必要がある。このため燃料配列を六角格子配
列とし、体積比を小さくする手段が採用されている。こ
のようにすることで従来型軽水炉に採用されている正方
格子配列に比べその体積比を１７４〜１／２にすること
が可能となる。The effective use of fissile plutonium produced by increasing this conversion ratio as nuclear fuel is advantageous both from the perspective of effective use of uranium resources and from the perspective of nuclear proliferation prevention. In recent years, high conversion type light water reactors have been developed that can effectively convert uranium-238 into plutonium by increasing the conversion ratio to 0.8 to 1.0, and can also effectively utilize plutonium. In this high conversion type light water reactor, in order to increase the conversion ratio mentioned above, it is necessary to reduce the volume ratio of moderator to fuel (Vm/Vf) in the reactor and harden the neutron spectrum. For this reason, a method is adopted in which the fuel is arranged in a hexagonal lattice arrangement to reduce the volume ratio. By doing so, it is possible to reduce the volume ratio to 174 to 1/2 compared to the square lattice arrangement employed in conventional light water reactors.
第５図は、上述したような高転換型軽水炉の炉心を構成
する燃料集合体を示してあり、燃料集合体１は六角柱形
の断面を有するチャンネルボックス２と、このチャンネ
ルボックス２内に六角格子状に配列された複数の燃料棒
３と、この燃料棒３の間に挿入される図示を省略した複
数の制御棒により構成されており、この燃料集合体１を
多数集合して炉心を形成している。また、炉心の外部雰
囲気は減速材となる軽水が充満している。FIG. 5 shows a fuel assembly constituting the core of a high conversion light water reactor as described above. It is composed of a plurality of fuel rods 3 arranged in a lattice pattern and a plurality of control rods (not shown) inserted between the fuel rods 3, and a reactor core is formed by assembling a large number of fuel assemblies 1. are doing. In addition, the atmosphere outside the core is filled with light water, which acts as a moderator.
（発明が解決しようとする問題点）
上述した炉心の最外周部では炉心周囲に充満している軽
水の効果で中性子スペクトラムは軟化している。核燃料
であるウラン−２３５やプルトニウム−２３９、プルト
ニウム２４１の中性子に対する核反応断面積は、中性子
エネルギーが低下する程大きくなるため、炉心最外周部
に位置する燃料集合体内の出力勾配は、第６図に示すよ
うに急激なものとなってしまい、燃料健全性上の問題が
おった。(Problems to be Solved by the Invention) At the outermost periphery of the core, the neutron spectrum is softened by the effect of the light water that is filled around the core. The nuclear reaction cross section of the nuclear fuels uranium-235, plutonium-239, and plutonium-241 with respect to neutrons increases as the neutron energy decreases, so the power gradient in the fuel assembly located at the outermost part of the core is as shown in Figure 6. As shown in Figure 2, the increase in fuel consumption became rapid, resulting in fuel integrity problems.
本発明は上述した問題点を解決するためになされたもの
で、炉心最外周部に位置する燃料集合体内の出力密度の
急激な勾配をなくして燃料集合体内の出力分布の平坦化
が可能となる燃料集合体を提供することを目的とする。The present invention has been made to solve the above-mentioned problems, and it is possible to flatten the power distribution within the fuel assembly by eliminating the sharp gradient in the power density within the fuel assembly located at the outermost periphery of the core. The purpose is to provide fuel assemblies.
［発明の構成］
（問題点を解決するための手段）
本発明によれば、複数の燃料棒を稠密格子状に収容し、
これを多数集合して炉心を構成する燃料集合体において
、この炉心最外周部に配置された燃料集合体の内部が核
分裂性物質密度の小さい燃料棒から構成された領域と核
分裂性物質密度の大きい燃料棒から構成された領域とを
有していることを特徴とする燃料集合体が得られる。[Structure of the Invention] (Means for Solving the Problems) According to the present invention, a plurality of fuel rods are housed in a dense grid,
In a fuel assembly that composes a reactor core by assembling a large number of these, the inside of the fuel assembly placed at the outermost part of the core is comprised of fuel rods with a low density of fissile material and a region with a high density of fissile material. A fuel assembly is obtained which is characterized in that it has a region made up of fuel rods.
（作 用）
本発明では、炉心最外周部に配置された燃料集合体内に
、核分裂性物質密度の小さい領域と核分裂性物質密度の
大きい領域とを設けることで炉心最外周部に配置された
燃料集合体内の出力分イ［の平坦化ができる。(Function) In the present invention, a region with a low fissile material density and a region with a high fissile material density are provided in the fuel assembly located at the outermost periphery of the reactor core. The output within the aggregate can be flattened.
（実施例）
以下、本発明の一実施例を図を参照にしながら説明する
。(Example) An example of the present invention will be described below with reference to the drawings.
第１図ｔよ本発明を適用した原子炉容器内の炉心４を示
しており、図示したように炉心４は六角柱状の多数の燃
料集合体により構成されている。炉心最外周部に配置さ
れた燃料集合体５が本発明を適用した燃料集合体である
。符号６は通常の燃料集合体を示している。FIG. 1t shows a reactor core 4 in a reactor vessel to which the present invention is applied, and as shown, the reactor core 4 is composed of a large number of hexagonal columnar fuel assemblies. A fuel assembly 5 arranged at the outermost periphery of the core is a fuel assembly to which the present invention is applied. Reference numeral 6 indicates a normal fuel assembly.
第２図は第１図のＡ部拡大図で必る。燃料棒は高濃縮ペ
レットを装荷した高濃縮燃料棒７と低濃縮ペレットを装
荷した低濃縮燃料棒８からなり、高濃縮燃料棒７により
高濃縮領域９が、低濃縮燃料棒８により低濃縮領域１０
がそれぞれ形成されている。Figure 2 is an enlarged view of section A in Figure 1. The fuel rods consist of high enrichment fuel rods 7 loaded with high enrichment pellets and low enrichment fuel rods 8 loaded with low enrichment pellets.The high enrichment fuel rods 7 provide a high enrichment region 9, and the low enrichment fuel rods 8 provide a low enrichment region. 10
are formed respectively.
このような構成の燃料集合体においてその出力分布を第
３図に示す。図中ａおよびｂは第２図のａおよびｂの位
置にそれぞれ対応している。図示したように、炉心外周
部の軽水の影響を受けるｂの位置近傍においても従来の
ような出力密度の急激な上昇が見られない。１なわら出
力分布の平坦化がはかれる。FIG. 3 shows the power distribution of a fuel assembly having such a configuration. In the figure, a and b correspond to positions a and b in FIG. 2, respectively. As shown in the figure, even in the vicinity of position b, which is affected by light water on the outer periphery of the core, there is no sharp increase in power density as in the conventional case. 1, the output distribution is flattened.
上述実施例では燃料の濃縮度の相違により核分裂性物質
密度の大小の領域を分割したが、例えば本発明の他の実
施例として、低濃縮領域を構成する燃料棒にプルトニウ
ム低寞化昨燃料を、高濃縮領域を構成する燃料棒にプル
トニウム高富化度燃料を用いても同様な効果が得られる
。In the above-mentioned embodiment, regions of large and small fissile material densities were divided based on the difference in fuel enrichment, but in another embodiment of the present invention, for example, plutonium low-density fuel was used in the fuel rods constituting the low enrichment region. A similar effect can be obtained by using high plutonium enrichment fuel in the fuel rods constituting the high enrichment region.
さらに本発明の他の実施例として、第４図に示すように
低濃縮領域１０の代わりに燃料棒のロッド径を他の燃料
棒よりも細くした燃料棒１１を用いてこれを核分裂性物
質密度の小さい領域１２としてもよい。この場合図示し
たように核分裂性物質密度の小さい領域１２と核分裂性
物質密度の大きい領域１３とは分割壁１４により分割す
ることが望ましい。Furthermore, as another embodiment of the present invention, as shown in FIG. 4, a fuel rod 11 having a rod diameter smaller than that of other fuel rods is used in place of the low enrichment region 10, and the fissile material density is increased. It may be a small area 12. In this case, as shown in the figure, it is desirable that a region 12 with a low density of fissile material and a region 13 with a high density of fissile material be divided by a dividing wall 14.
［発明の効果］
以上説明したように本発明の燃料集合体によれば、軽水
の効果を受ける炉心最外周部の燃料集合体においてもそ
の燃料集合体内の出力分布の平坦化が可能となる。[Effects of the Invention] As explained above, according to the fuel assembly of the present invention, it is possible to flatten the power distribution within the fuel assembly even in the fuel assembly at the outermost periphery of the core, which is subject to the effect of light water.
第１図は本発明に係る燃料集合体を適用した炉心の構成
を示す図、第２図は第１図のＡ部拡大断面図、第３図は
実施例の燃料集合体内の出力分布を示す図、第４図は本
発明に係る他の実施例の燃料集合体を示す横断面図、第
５図は従来の燃料集合体を示す横断面図、第６図は従来
の燃料集合体内の出力分布を示す図である。
２・・・・・・・・・チャンネルボックス４・・・・・
・・・・炉心
５・・・・・・・・・燃料集合体
７・・・・・・・・・高濃縮燃料棒
８・・・・・・・・・低濃縮燃料棒
９・・・・・・・・・高濃縮領域
１０・・・・・・・・・低濃縮領域
１１・・・・・・・・・小ロッド径燃料１２・・・・・
・・・・核分裂性物質密度の小さい領域１３・・・・・
・・・・核分裂性物質密度の大ぎい領域１４・・・・・
・・・・分離壁
第１図
第２図
婁合体肉位ス
第３図
第４図
第５図
第６図Fig. 1 is a diagram showing the configuration of a reactor core to which the fuel assembly according to the present invention is applied, Fig. 2 is an enlarged sectional view of section A in Fig. 1, and Fig. 3 shows the power distribution in the fuel assembly of the embodiment. 4 is a cross-sectional view showing a fuel assembly according to another embodiment of the present invention, FIG. 5 is a cross-sectional view showing a conventional fuel assembly, and FIG. 6 is a cross-sectional view showing a conventional fuel assembly. It is a figure showing distribution. 2...Channel box 4...
... Core 5 ... Fuel assembly 7 ... Highly enriched fuel rods 8 ... Low enriched fuel rods 9 ... ......High enrichment region 10...Low enrichment region 11...Small rod diameter fuel 12...
...Region 13 with low fissile material density...
...Region of high fissile material density 14...
・・・・Separation wall Fig. 1 Fig. 2 Combination body posture Fig. 3 Fig. 4 Fig. 5 Fig. 6
Claims (4)
集合して炉心を構成する燃料集合体において、 前記炉心最外周部に配置された前記燃料集合体の内部が
核分裂性物質密度の小さい燃料棒から構成された領域と
核分裂性物質密度の大きい燃料棒から構成された領域と
を有していることを特徴とする燃料集合体。(1) In a fuel assembly in which a plurality of fuel rods are housed in a dense lattice and a large number of these are assembled to constitute a reactor core, the interior of the fuel assembly arranged at the outermost periphery of the core has a fissile material density. 1. A fuel assembly comprising a region made up of fuel rods with a small density of fissile material and a region made up of fuel rods with a large density of fissile material.
料棒で、核分裂性物質密度の大きい燃料棒が高濃縮度の
燃料棒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。(2) Claim 1, characterized in that the fuel rods with low fissile material density are low enrichment fuel rods, and the fuel rods with high fissile material density are high enrichment fuel rods. fuel assembly.
低富化度燃料捧で、核分裂性物質密度の大きい燃料棒が
プルトニウム高富化度燃料棒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) Claim 1, characterized in that the fuel rods with a low density of fissile material are fuel rods with a low enrichment of plutonium, and the fuel rods with a high density of fissile material are fuel rods with a high enrichment of plutonium. Fuel assembly as described.
該核分裂性物質密度の大きい燃料棒のロッド径よりも小
さい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。(4) The rod diameter of the fuel rod with low fissile material density is
The fuel assembly according to claim 1, characterized in that the rod diameter is smaller than the rod diameter of the fuel rod having a high fissile material density.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61167575A JPS6324194A (en) | 1986-07-16 | 1986-07-16 | Fuel aggregate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61167575A JPS6324194A (en) | 1986-07-16 | 1986-07-16 | Fuel aggregate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6324194A true JPS6324194A (en) | 1988-02-01 |
Family
ID=15852284
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61167575A Pending JPS6324194A (en) | 1986-07-16 | 1986-07-16 | Fuel aggregate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6324194A (en) |
-
1986
- 1986-07-16 JP JP61167575A patent/JPS6324194A/en active Pending
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