JPS63108294A - Fuel aggregate for boiling water type reactor - Google Patents
Fuel aggregate for boiling water type reactorInfo
- Publication number
- JPS63108294A JPS63108294A JP61251854A JP25185486A JPS63108294A JP S63108294 A JPS63108294 A JP S63108294A JP 61251854 A JP61251854 A JP 61251854A JP 25185486 A JP25185486 A JP 25185486A JP S63108294 A JPS63108294 A JP S63108294A
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- gadolinia
- rods
- enrichment
- rod
- 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.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims description 129
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 16
- 238000009835 boiling Methods 0.000 title claims description 7
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 claims description 96
- 229910052778 Plutonium Inorganic materials 0.000 claims description 13
- OYEHPCDNVJXUIW-UHFFFAOYSA-N plutonium atom Chemical compound [Pu] OYEHPCDNVJXUIW-UHFFFAOYSA-N 0.000 claims description 13
- 239000003758 nuclear fuel Substances 0.000 claims description 3
- 230000009257 reactivity Effects 0.000 description 13
- 229910052770 Uranium Inorganic materials 0.000 description 9
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000002574 poison Substances 0.000 description 3
- 231100000614 poison Toxicity 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 206010073306 Exposure to radiation Diseases 0.000 description 1
- WZECUPJJEIXUKY-UHFFFAOYSA-N [O-2].[O-2].[O-2].[U+6] Chemical compound [O-2].[O-2].[O-2].[U+6] WZECUPJJEIXUKY-UHFFFAOYSA-N 0.000 description 1
- 230000005262 alpha decay Effects 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- SHZGCJCMOBCMKK-KGJVWPDLSA-N beta-L-fucose Chemical compound C[C@@H]1O[C@H](O)[C@@H](O)[C@H](O)[C@@H]1O SHZGCJCMOBCMKK-KGJVWPDLSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000008234 soft water Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 229910000439 uranium oxide Inorganic materials 0.000 description 1
- JFALSRSLKYAFGM-OIOBTWANSA-N uranium-235 Chemical compound [235U] JFALSRSLKYAFGM-OIOBTWANSA-N 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
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (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）
本発明は燃料集合体、特にプルトニウムを富化した燃料
棒を有する沸騰水型原子炉用燃料集合体（以下ＢｗＲ燃
料集合体という）に関する。Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a fuel assembly, particularly a boiling water reactor fuel assembly (hereinafter referred to as a BwR fuel assembly) having plutonium-enriched fuel rods. related to the body).
（従来の技術）
第４図は従来の燃料集合体の斜視図である。この図にお
いて、断面方形状のチャンネルボックス１内には、多数
の燃料ペレットを燃料波′ＩＩ！管内に装填して成る多
数の燃料棒２が格子状に配置されており、それらの燃料
棒は上部タイプレート３、下部タイプレート４によって
支持されている。また、燃料棒２の中間部はスペーサ５
により燃料棒相互間およびチャンネルボックス１との間
隔を維持されている。(Prior Art) FIG. 4 is a perspective view of a conventional fuel assembly. In this figure, a large number of fuel pellets are placed inside a channel box 1 having a rectangular cross section. A large number of fuel rods 2 loaded into a tube are arranged in a grid pattern, and these fuel rods are supported by an upper tie plate 3 and a lower tie plate 4. In addition, the middle part of the fuel rod 2 is provided with a spacer 5.
The spacing between the fuel rods and the channel box 1 is maintained by the fuel rods.
第５図は、濃縮ウランのみを燃料とする従来の燃料集合
体の燃料棒の配置を示す、この図において二重臼は燃料
棒をあられし、その中に記入された数字１〜７は数字１
を最高とし同７を最低とするＩＪ！ｘｓの濃縮度、文字
Ｗはウォータロッド、文字Ｇは可燃性毒物であるガドリ
ニアの濃度が１〜８％のガドリニア燃料棒を示す。すな
わち、数字１は最高濃縮度燃料棒、２は高濃縮度燃料棒
、数字３〜５は中間濃縮度燃料棒、数字６は低濃縮度燃
料棒、数字７は最低濃縮度燃料棒である。なお、図中Ｃ
Ｒは制御棒を示す。Figure 5 shows the arrangement of fuel rods in a conventional fuel assembly that uses only enriched uranium as fuel. 1
IJ is the highest and 7 is the lowest! The enrichment of xs, the letter W indicates a water rod, and the letter G indicates a gadolinia fuel rod with a concentration of 1 to 8% of gadolinia, a burnable poison. That is, the number 1 is the highest enrichment fuel rod, the number 2 is the high enrichment fuel rod, the numbers 3 to 5 are the intermediate enrichment fuel rods, the number 6 is the low enrichment fuel rod, and the number 7 is the lowest enrichment fuel rod. In addition, C in the figure
R indicates a control rod.
燃料棒、ウォータロッドの数の和は６４本であり、２本
のウォータロッドＷは、チャンネルボックス１の制御棒
に隣接しない隅角間を連ねる対角線の中央に並んで配置
されている。また、最高濃縮度燃料棒１は、前記対角線
上のウォータロッドＷの隣の燃料棒配置位置を原点とす
る正方形状に計１２本が配置され、高濃縮度燃料棒２は
前記正方形内の２つの燃料棒配置位置および前記正方形
に隣接し各辺の中央に対向するそれぞれの２つの燃料棒
配置位置計１０本が配置されている。ガドリニア燃 □
料捧Ｇは、前記正方形周辺に配置した高濃縮度燃料にそ
れぞれ隣接した配置位置に計８本が配置され、中間濃縮
度燃料棒３は、高濃縮度燃料棒２およびガドリニア燃料
棒Ｇを含む燃料棒の列を辺とする正方形の原点に配置さ
れている。最外周の燃料棒の列は、７，６，５，４，４
．５，６，７となっている。The total number of fuel rods and water rods is 64, and the two water rods W are arranged in the center of a diagonal line connecting the corners of the channel box 1 that are not adjacent to the control rods. Further, a total of 12 highest enrichment fuel rods 1 are arranged in a square shape whose origin is the fuel rod arrangement position next to the water rod W on the diagonal line, and the high enrichment fuel rods 2 are arranged in two of the squares within the square. Ten fuel rod placement positions and two fuel rod placement position indicators adjacent to the square and facing each other at the center of each side are arranged. Gadolinia fuel □
A total of eight fuel rods G are arranged at positions adjacent to the high enrichment fuels arranged around the square, and the intermediate enrichment fuel rods 3 include the high enrichment fuel rods 2 and the gadolinia fuel rods G. It is located at the origin of a square whose sides are the rows of fuel rods. The outermost fuel rod rows are 7, 6, 5, 4, 4.
．． 5, 6, 7.
第６図は第４図の燃料集合体と反応度的にはほぼ等価と
なるよう、プルトニウムを富化した燃料棒（ＭＯＸ燃料
棒）を使用した燃料集合体の燃料棒の配置を示す、数字
１１〜１６はプルトニウムの富化度を数字１１を最高と
して示す、最高富化度燃料棒１１は第３図における最高
濃縮度燃料棒１と同様に配置されている。しかしながら
、ウォータロッドＷに隣接する配置位置には、プルトニ
ウムを富化したガドリニア燃料棒Ｇが配置されている。Figure 6 shows the arrangement of fuel rods in a fuel assembly using plutonium-enriched fuel rods (MOX fuel rods) so that the reactivity is almost equivalent to that of the fuel assembly in Figure 4. Numerals 11 to 16 indicate plutonium enrichment, with number 11 being the highest. The highest enrichment fuel rods 11 are arranged in the same manner as the highest enrichment fuel rods 1 in FIG. However, in a position adjacent to the water rod W, a plutonium-enriched gadolinia fuel rod G is arranged.
最高富化度燃料棒１１の配置された正方形の外側の正方
形を形成する配置位には制御棒ＣＲのタイロッドに近接
した頂点をガドリニア燃料棒Ｇとして、前記頂点からの
二辺に頂点から順にＧ、 １２． Ｇ、 １２． Ｇ。At the arrangement position forming the outer square of the square in which the highest enrichment fuel rods 11 are arranged, the apex near the tie rod of the control rod CR is designated as the gadolinia fuel rod G, and the two sides from the apex are arranged with G in order from the apex. , 12. G, 12. G.
１３の燃料棒を配置し、他の二辺には前記頂点の対頂点
から順にＧ、 １２． Ｇ、 １２． Ｇ、 １３の燃
料棒を配置する。最外周の燃料棒の列は１６．１５．１
４．１３゜１３、１４．．１５．．１６となっている。13 fuel rods are arranged, and on the other two sides, G, 12. G, 12. G. Place 13 fuel rods. The outermost row of fuel rods is 16.15.1
4.13°13, 14. ．． 15. ．． It is 16.
第５図、第６図かられかるようにＭＯＸ燃料棒を使用し
た燃料集合体では通常のそれよりも、ガドリニア燃料棒
の本数が多くなっている。As can be seen from FIGS. 5 and 6, a fuel assembly using MOX fuel rods has a greater number of gadolinia fuel rods than a normal fuel assembly.
すなわち、一般にＭＯＸ燃料では、ＵＯ□燃料に比し中
性子スペクトルが硬いため、ガドリニアの反応度価値が
ＵＯ□燃料の場合とがなり異り、ガドリニアの中性子吸
収断面積は熱群中性子エネルギに対して大きく熱外に対
して小さいので、中性子スペクトルが硬くなるガドリニ
アの反応度価値が下り、同時にガドリニアの燃焼速度が
遅くなる。In other words, in general, MOX fuel has a harder neutron spectrum than UO□ fuel, so the reactivity value of gadolinia is different from that of UO□ fuel, and the neutron absorption cross section of gadolinia is relative to the thermal group neutron energy. Since it is large and small with respect to extrathermia, the reactivity value of gadolinia, which hardens the neutron spectrum, decreases, and at the same time, the burning rate of gadolinia slows down.
そこで、ガドリニアによる反応度制御をＵＯ，燃料と同
様に行うためには、ガドリニア濃度を低くし、ガドリニ
ア入り燃料棒の本数を多くする必要がある。Therefore, in order to perform reactivity control using gadolinia in the same manner as UO and fuel, it is necessary to lower the gadolinia concentration and increase the number of gadolinia-containing fuel rods.
例えば第５図に示すＵＯ２燃料のガドリニアが３ｗ１０
Ｘｓ本であるのに対して、第６図に示したＭＯＸ燃料棒
では１．５ｖ１０ Ｘ １２となっている。For example, the UO2 fuel gadolinia shown in Figure 5 is 3w10.
In the MOX fuel rod shown in FIG. 6, the number of fuel rods is 1.5v10 x 12.
プルトニウムはα崩壊をするため、人体への内部被曝を
防止する必要があり、また崩壊、自発核分裂によって中
性子、γ線を放出するため、遮蔽装置が必要となる。従
って、ＭＯＸ燃料は完全に密閉された状態で成型加工す
ることが必要であり、成型加工工程、設備等の保守点検
についてＵＯ□燃料の場合とは異る配慮を必要とする。Because plutonium undergoes α-decay, it is necessary to prevent internal exposure to radiation to the human body, and because plutonium emits neutrons and gamma rays through decay and spontaneous fission, shielding equipment is required. Therefore, MOX fuel needs to be molded in a completely hermetically sealed state, and requires different consideration from the case of UO□ fuel regarding the molding process, maintenance and inspection of equipment, etc.
核燃料製造工場ではウラン−２３５′ａ縮度別、プルト
ニウム富化度別、ガドリニア棒の種類別に製造ラインが
設定されるが、ウラン燃料製造の場合に比し、ＭＯ！燃
料の製造設備は密閉されており。At nuclear fuel manufacturing plants, production lines are set up for each degree of uranium-235'a reduction, plutonium enrichment, and type of gadolinia rod, but compared to uranium fuel production, MO! The fuel manufacturing equipment is sealed.
複雑化しているので、製造コストは著しく高価である。Due to the increased complexity, manufacturing costs are significantly higher.
従って、 ＭＯＸ燃料燃料上下方向に一様富化度にする
とともに種類を極力少くすることが望ましい。また、ガ
ドリニア棒の成型加工において。Therefore, it is desirable to make the enrichment level of MOX fuel uniform in the vertical direction and to minimize the number of types. Also, in the molding process of gadolinia rods.
ガドリニア、酸化ウラン、酸化プルトニウムの３種類の
粉末を取扱う場合、工程、装置は一層複雑高価となる。When handling three types of powder: gadolinia, uranium oxide, and plutonium oxide, the process and equipment become even more complex and expensive.
従ってガドリニア捧にはプルトニウムを含有させない設
計が望ましい。Therefore, it is desirable to design the gadolinia sacrificial material so that it does not contain plutonium.
さて、軽水炉用ＭＯＸ燃料集合体の設計は大別して、以
下の２種類に分けられている。Now, the design of MOX fuel assemblies for light water reactors can be roughly divided into the following two types.
第１の設計例は燃料集合体の制御棒から離れた中央部分
にＭＯＸ燃料（全本数の約１７２以下）を使用し、外周
部はＵＯ１燃料燃料使用するアイランド型設計であり、
例えば、特願昭４７−９５８３３号（特公昭５５−２６
４３７号）に於て実例が示されている。 この場合は多
数のＵ０２燃料棒を使用するため、可燃性毒物（ガドリ
ニア）をＵＯ□燃料燃料のみ添加させることが可能であ
る。The first design example is an island type design that uses MOX fuel (approximately 172 or less of the total number) in the central part of the fuel assembly away from the control rods, and uses UO1 fuel in the outer periphery.
For example, Japanese Patent Application No. 47-95833 (Japanese Patent Application No. 55-26
An example is given in No. 437). In this case, since a large number of U02 fuel rods are used, it is possible to add burnable poison (gadolinia) only to the UO□ fuel.
第２の設計例は燃料集合体あたりのプルトニウム装荷量
を極力増すために、すべての燃料棒にＭＯＸ燃料棒を使
用するディスクリート型設計である。この場合は、可燃
性毒物を含む燃料棒としてＭＯＸ燃料棒が使用されてい
る。第４図に示したものはこれに含まれる。また第１と
第２の中間の設計として、一部の燃料棒としてυ０□燃
料棒を使用した設計も考えられている。The second design example is a discrete design that uses MOX fuel rods for all fuel rods to maximize the plutonium loading per fuel assembly. In this case, MOX fuel rods are used as fuel rods containing burnable poison. This includes what is shown in Figure 4. Furthermore, as an intermediate design between the first and second, a design using υ0□ fuel rods as some of the fuel rods is also being considered.
本発明は上記第２の設計のディスクリート型燃料のよう
な多数のＭＯＸ燃料棒から構成される燃料集合体の軸方
向出力分布平坦化設計に関連する。The present invention relates to an axial power distribution flattening design for a fuel assembly comprised of a large number of MOX fuel rods, such as the discrete fuel of the second design.
ＢｗＲ炉心では、炉心上方でボイド率が高くなり、ボイ
ド反応度差によって、炉心下部に出力ビーキングが生ず
ることが知られている。炉心軸方向出力分布平坦化のた
めには、上下ボイド反応度差を相殺するように燃料上下
に核分裂性物質量やガドリニアを分布させればよい、上
記第１の設計例ではこれをＵＯ□燃料棒に適用すること
によって容易に実施できるが、第２の設計例ではＭＯＸ
燃料燃料上雑になり、燃料製造コストの上昇をまねく。It is known that in a BwR core, the void ratio increases in the upper part of the core, and power peaking occurs in the lower part of the core due to the difference in void reactivity. In order to flatten the power distribution in the axial direction of the core, it is sufficient to distribute the amount of fissile material and gadolinia above and below the fuel so as to offset the difference in reactivity between the upper and lower voids.In the first design example above, this is Although it can be easily implemented by applying it to a rod, in the second design example MOX
The fuel quality becomes poor, leading to an increase in fuel manufacturing costs.
（発明が解決しようとする問題点）
本発明は上記情報に鑑みてなされたもので、全燃料棒の
うち、ＭＯＸ燃料棒が多数を占める燃料集合体において
、 ＭＯＸ燃料燃料上造を複雑にすることなく、炉心
上下方向出力分布を平坦化できるＢｖＲ用燃料集合体を
得ることを 目的とするものである。(Problems to be Solved by the Invention) The present invention has been made in view of the above information, and it solves the problem of complicating the fabrication of MOX fuel in a fuel assembly in which MOX fuel rods account for the majority of all fuel rods. The purpose of this project is to obtain a fuel assembly for BvR that can flatten the power distribution in the vertical direction of the core without causing any damage.
（問題点を解決するための手段）
上記目的を達成するために、本発明は多数のＭＯＸ燃料
燃料上びプルトニウムを含まないガドリ、ニア燃料棒を
正方形の格子状に配置した沸騰水型原子炉用燃料集合体
において、前記ガドリニア燃料棒の上下方向に濃縮度も
しくはガドリニア濃度を分布させたことを特徴とするも
のである。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a boiling water nuclear reactor in which a large number of MOX fuels and plutonium-free Gadri fuel rods are arranged in a square lattice. This fuel assembly is characterized in that the enrichment or gadolinia concentration is distributed in the vertical direction of the gadolinia fuel rods.
（実施例） 第１図は本発明の実施例の模式的断面図である。(Example) FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention.
同図において、数字１８〜２０は１８を最高として番号
順にプルトニウムの富化度を示す、また、Ｇは３．０ｖ
１０濃縮度のウランに２．５ｖへのガドリニアを含むガ
ドリニア捧、Ｗはウォータロッドを示す、この実施例で
は、燃料棒配置位置の外側から２列目を辺とする正方形
の各頂点を除き、最高富化度の燃料棒１８が配置され、
前記各頂点には中宮化度の燃料棒１９が配置されている
。また、最外側の列をなす正方形の頂点には最低富化度
の燃料棒２０が。In the figure, numbers 18 to 20 indicate the enrichment of plutonium in numerical order with 18 being the highest, and G is 3.0v.
In this example, the uranium of 10 enrichment contains gadolinia to 2.5V, W indicates a water rod, except for each vertex of a square whose sides are the second row from outside the fuel rod arrangement position The fuel rods 18 with the highest enrichment are arranged,
At each of the apexes, a medium-sized fuel rod 19 is arranged. Moreover, the lowest enrichment fuel rods 20 are located at the vertices of the squares forming the outermost row.
それに隣接した配置位置にはガドリニア燃料棒Ｇがそれ
ぞれ配置され、他の位置には中宮化度の燃料棒１９が配
置されている。Gadolinia fuel rods G are arranged at adjacent positions, and fuel rods 19 of medium grade are arranged at other positions.
上記構成の本発明にあっては、ガドリニア棒Ｇが中性子
スペクトルの軟い水ギャップに沿った位置に配置されて
いるため、中性子反応率が増す。In the present invention having the above configuration, since the gadolinia rod G is arranged at a position along the soft water gap of the neutron spectrum, the neutron reaction rate increases.
そのため、ガドリニア捧１本あたりの中性子吸収量も増
すので、ガドリニア捧本数は８本となる。Therefore, the amount of neutron absorption per gadolinia strip increases, so the number of gadolinia strips becomes eight.
また、これらのガドリニア捧上下に濃縮度差あるいはガ
ドリニア濃度差をつけると、中性子反応量の上下差も増
すので、燃料上下反応度差が増す。Furthermore, if there is a difference in enrichment or a difference in gadolinia concentration between the upper and lower portions of these gadolinia feeds, the difference between the upper and lower neutron reaction amounts will also increase, so the difference in reactivity between the upper and lower fuels will increase.
たとえば、ガドリニア捧の下半分で天然ウラン、上半分
で３．０％１００濃縮度ウランとした場合、燃料」二下
反応度差は、上下方向一種燃料と比べると、約２％Δに
だけ小さくなる。第２図は、このＭＯＸ燃料集合体を炉
心に装荷したときの炉心軸方向出力分布平坦の効果を示
したものである。ここでは、サイクル初期での制御棒全
引抜の状態での炉心軸方向出力分布を示す０図中曲線３
１は、従来型の軸方向一種燃料の場合、曲線３２は本発
明になる場合であるが、軸方向出力分布平坦化の効果は
明らかである。この例では、燃料上下領域の切れ目は炉
心下端から全長の１０／２４となっている。曲線３１に
示す従来型炉心の場合、出力ビーキングは全長の１／４
以下で生じているが、切れ目位置が約１／３ないし１／
２の範囲にあれば本発明の目的が達成される。For example, if natural uranium is used in the lower half of the gadolinia bar and 3.0% 100 enrichment uranium is used in the upper half, the reactivity difference between the two fuels is only about 2%Δ smaller than that of the first type fuel in the vertical direction. Become. FIG. 2 shows the effect of flattening the power distribution in the axial direction of the reactor core when this MOX fuel assembly is loaded into the reactor core. Here, curve 3 in Figure 0 shows the power distribution in the core axial direction when the control rods are fully withdrawn at the beginning of the cycle.
Curve 1 is for the conventional type of axial single fuel, and curve 32 is for the present invention, but the effect of flattening the axial power distribution is clear. In this example, the cut between the upper and lower fuel regions is 10/24 of the total length from the lower end of the core. In the case of the conventional core shown in curve 31, the power peaking is 1/4 of the total length.
This occurs in the following cases, but the cut position is approximately 1/3 to 1/3
The object of the present invention can be achieved within the range of 2.
また、本実施例で図中コーナーロッド２０は、最も中性
子反応率が大きい場所なので、 これをＵＯ１燃料棒と
すると、これに濃縮度差やガドリニア濃度差をつけるこ
とによって、より大きい上下反応度差が得られ、プルト
ニウム富化度を１種類減らすことができる。In addition, in this example, the corner rod 20 in the figure is the location where the neutron reaction rate is the highest, so if this is the UO1 fuel rod, by adding an enrichment difference and a gadolinia concentration difference to this, the upper and lower reactivity differences will be larger. is obtained, and the plutonium enrichment can be reduced by one type.
さらに、第６図に示した、従来型のＭＯＸ燃料集合体に
於て、ガドリニア棒にプルトニウムを含ませない場合、
この燃料棒に濃縮度やガドリニア濃度を分布させること
によって、ＭＯＸ燃料燃料複雑にすることなく、燃料上
下方向に反応度を分布させることができる。たとえば、
ガドリニア捧の下半分で天然ウラン、上半分で３，０ｖ
１０１縮度ウランとすると、燃料上下の反応度差は、上
下一様の場合と比べて約２％Δにだけ小さくなり、上下
ボイド反応度差をほぼ相殺できる。同様に、同図におけ
る１２本のガドリニア捧のうち、数本について上部でガ
ドリニア濃度を０とした場合も同様に出力分布を平坦化
することができる。この場合は上記実施例に比べると、
ガドリニア棒は１２本であるが、従来のＭＯＸ燃料集合
体がそのまま使用できるという利点がある。Furthermore, in the conventional MOX fuel assembly shown in Figure 6, if the gadolinia rods do not contain plutonium,
By distributing enrichment and gadolinia concentration in this fuel rod, reactivity can be distributed in the vertical direction of the fuel without making the MOX fuel complex. for example,
Natural uranium in the lower half of gadolinia, 3.0v in the upper half
When using uranium with a degree of shrinkage of 101, the difference in reactivity between the upper and lower sides of the fuel becomes smaller by about 2%Δ compared to the case where the upper and lower sides are uniform, and the difference in reactivity between the upper and lower voids can be almost canceled out. Similarly, the output distribution can be similarly flattened when the gadolinia concentration is set to 0 in the upper part of some of the 12 gadolinia beams in the figure. In this case, compared to the above example,
Although there are 12 gadolinia rods, the advantage is that the conventional MOX fuel assembly can be used as is.
なお、上記各実施例で示した数字は一例であり、第３図
に示すように濃縮度差やガドリニア濃度の組み合わせは
任意であり、両者を併用することによって本発明の目的
を達成することができる。Note that the numbers shown in each of the above examples are just examples, and as shown in FIG. 3, the concentration difference and the gadolinia concentration can be combined arbitrarily, and the purpose of the present invention can be achieved by using both together. can.
以上説明したように１本発明によればガドリニア燃料棒
の母材をウランのみとし、この燃料の上下方向に濃縮度
分布や、ガドリニア濃度分布をつけることによって、Ｍ
ＯＸ燃料の製造を複雑にすることなく、燃料上下方向に
反応度をつけたＭＯＸ燃料集合体を作ることができる。As explained above, according to the present invention, the base material of the gadolinia fuel rod is made of uranium only, and by providing an enrichment distribution and a gadolinia concentration distribution in the vertical direction of this fuel, M
It is possible to produce an MOX fuel assembly with reactivity in the vertical direction of the fuel without complicating the production of OX fuel.
また、ガドリニア棒を水ギャップに面した位置に配置す
ることによって、より少ない本数で炉心上下方向出力を
平坦化できるＢＶＲ用燃料集合体が得られる。Furthermore, by arranging the gadolinia rods at positions facing the water gap, a fuel assembly for a BVR can be obtained that can flatten the core vertical output with a smaller number of rods.
第１図は本発明の一実施例の模式的断面図、第２図は本
発明と従来型の軸方向一様燃料の炉心軸方向出力分布を
比較した図、第３図は本発明に係るガドリニア枠中での
ウラン濃縮度、ガドリニア濃度分布の組み合わせを示す
図、第４図は本発明が適用される燃料集合体の一部を切
除して示す斜視図、第５図、第６図はそれ−ぞれ従来の
燃料集合体の模式的断面図である。
１・・・チャンネルボックス
２・・・燃料棒
３・・・上部タイプレート
４・・・下部タイプレート
５・・・スペーサ
（８７３３）代理人弁理士 猪 股 祥 晃（ほか１名
）Ｒ
第 １ 回
半 ２ 図
第３図 。
第 ４ 回Figure 1 is a schematic sectional view of an embodiment of the present invention, Figure 2 is a diagram comparing the core axial power distribution of the present invention and conventional axially uniform fuel, and Figure 3 is a diagram of the core axial power distribution according to the present invention. A diagram showing a combination of uranium enrichment and gadolinia concentration distribution in a gadolinia frame, FIG. 4 is a perspective view showing a partially cut away fuel assembly to which the present invention is applied, and FIGS. 5 and 6 are FIG. 1 is a schematic cross-sectional view of a conventional fuel assembly; 1... Channel box 2... Fuel rod 3... Upper tie plate 4... Lower tie plate 5... Spacer (8733) Attorney Yoshiaki Inomata (and 1 other person) R 1st Half 2 Figure 3. 4th
Claims (3)
トニウムを含まないガドリニア燃料棒を正方形の格子状
に配置した沸騰水型原子炉用燃料集合体において、プル
トニウムを含まないガドリニア棒燃料棒の上下方向に濃
縮度もしくはガドリニア濃度を分布させたことを特徴と
する沸騰水型原子炉用燃料集合体。(1) In a boiling water reactor fuel assembly in which a large number of plutonium-enriched fuel rods and plutonium-free gadolinia fuel rods are arranged in a square lattice, the vertical direction of the plutonium-free gadolinia fuel rods A fuel assembly for a boiling water reactor, characterized in that the enrichment or gadolinia concentration is distributed.
ている特許請求の範囲第１項記載の沸騰水型原子炉用燃
料集合体。(2) A fuel assembly for a boiling water reactor according to claim 1, wherein the gadolinia rod is disposed at a position facing the water gap.
長の約１／３ないし１／２位置である特許請求の範囲第
１項記載の沸騰水型原子炉用燃料集合体。(3) The fuel assembly for a boiling water reactor according to claim 1, wherein the cut position between the upper and lower fuel regions is approximately 1/3 to 1/2 of the total length from the lower end of the fuel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61251854A JPH065320B2 (en) | 1986-10-24 | 1986-10-24 | Fuel assembly for boiling water reactor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61251854A JPH065320B2 (en) | 1986-10-24 | 1986-10-24 | Fuel assembly for boiling water reactor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63108294A true JPS63108294A (en) | 1988-05-13 |
| JPH065320B2 JPH065320B2 (en) | 1994-01-19 |
Family
ID=17228907
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61251854A Expired - Lifetime JPH065320B2 (en) | 1986-10-24 | 1986-10-24 | Fuel assembly for boiling water reactor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH065320B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04290989A (en) * | 1991-03-19 | 1992-10-15 | Hitachi Ltd | Fuel assembly |
| US5377247A (en) * | 1990-04-27 | 1994-12-27 | Kabushiki Kaisha Toshiba | Fuel assembly of nuclear reactor |
| JP2009162739A (en) * | 2007-12-13 | 2009-07-23 | Hitachi-Ge Nuclear Energy Ltd | Fuel assembly |
| JP2021113769A (en) * | 2020-01-21 | 2021-08-05 | 日立Ｇｅニュークリア・エナジー株式会社 | Fuel aggregate |
-
1986
- 1986-10-24 JP JP61251854A patent/JPH065320B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5377247A (en) * | 1990-04-27 | 1994-12-27 | Kabushiki Kaisha Toshiba | Fuel assembly of nuclear reactor |
| JPH04290989A (en) * | 1991-03-19 | 1992-10-15 | Hitachi Ltd | Fuel assembly |
| JP2009162739A (en) * | 2007-12-13 | 2009-07-23 | Hitachi-Ge Nuclear Energy Ltd | Fuel assembly |
| JP2010237223A (en) * | 2007-12-13 | 2010-10-21 | Hitachi-Ge Nuclear Energy Ltd | Fuel assembly |
| JP2021113769A (en) * | 2020-01-21 | 2021-08-05 | 日立Ｇｅニュークリア・エナジー株式会社 | Fuel aggregate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH065320B2 (en) | 1994-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |