JPH10325890A - Fuel assembly - Google Patents
Fuel assemblyInfo
- Publication number
- JPH10325890A JPH10325890A JP9133197A JP13319797A JPH10325890A JP H10325890 A JPH10325890 A JP H10325890A JP 9133197 A JP9133197 A JP 9133197A JP 13319797 A JP13319797 A JP 13319797A JP H10325890 A JPH10325890 A JP H10325890A
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- fuel assembly
- average
- region
- enrichment
- 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
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
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は沸騰水型原子炉用の
燃料集合体に係り、特に高燃焼度化を図るのに好適な燃
料集合体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel assembly for a boiling water reactor, and more particularly to a fuel assembly suitable for achieving high burnup.
【０００２】[0002]
【従来の技術】単位重量当たりのウランから発生するエ
ネルギーを増大させることによって燃料経済性を改善す
る、いわゆる高燃焼度化炉心の開発が進んでいる。近年
の原子炉用燃料集合体は、その上下端部に天然ウランブ
ランケットを有している。この天然ウランブランケット
は、以下に示す効果により燃料経済性を高めることが可
能である。2. Description of the Related Art A so-called high burn-up core, which improves fuel economy by increasing the energy generated from uranium per unit weight, is being developed. Recent nuclear fuel assemblies have a natural uranium blanket at the upper and lower ends. This natural uranium blanket can improve fuel economy by the following effects.
【０００３】(１)上下端部出力を下げることによって上
下方向への中性子の漏れを抑えることができるため、中
性子経済性が向上する。[0003] (1) By lowering the output of the upper and lower ends, it is possible to suppress the leakage of neutrons in the vertical direction, thereby improving the neutron economy.
【０００４】(２)上下端の天然ウランブランケット部に
可燃性毒物が含まれていないため、端部での可燃性毒物
の燃え残りがなく中性子経済性が向上する。(2) Since the burnable poison is not contained in the natural uranium blanket portions at the upper and lower ends, the burnable poison is not left unburned at the end, and the neutron economy is improved.
【０００５】例えば、特開昭59-38684号公報には、燃料
有効長のうち上端部１／１２，下端部１／２４を天然ウ
ランブランケットとした構成が記載されている。また、
燃料集合体中に含まれる核分裂性物質量が一定の条件下
で、天然ウランブランケットを用いた場合と天然ウラン
ブランケットを用いない場合とを比較すると、天然ウラ
ンブランケットを上下端部に配置することにより、約７
％の燃料経済性向上効果があることが同公報に記載され
ている。For example, Japanese Patent Application Laid-Open No. 59-38684 describes a configuration in which the upper end 1/12 and the lower end 1/24 of the active fuel length are made of a natural uranium blanket. Also,
When the amount of fissile material contained in the fuel assembly is constant and the natural uranium blanket is used and the natural uranium blanket is not used, the natural uranium blanket is located at the upper and lower ends. , About 7
It is described in the publication that the fuel economy is improved by 5%.
【０００６】[0006]
【発明が解決しようとする課題】しかし、更なる高燃焼
度化を目指すに際して、従来の天然ウランブランケット
は、次に挙げるような問題点を有する。However, the conventional natural uranium blanket has the following problems when aiming at higher burnup.
【０００７】(１)天然ウランブランケットを炉心上下端
部に配置すると、炉心上下端部出力が低下し、炉心中央
部の軸方向出力ピーキングが増加する。高燃焼度化燃料
の熱的余裕を確保するうえで、天然ウランブランケット
の使用は不利である。(1) When a natural uranium blanket is arranged at the upper and lower ends of the core, the power at the upper and lower ends of the core decreases, and the axial power peaking at the center of the core increases. Use of a natural uranium blanket is disadvantageous in securing a thermal margin for the high burnup fuel.
【０００８】(２)高燃焼度化を達成するためには燃料集
合体平均濃縮度を上げる必要があるが、使用できるペレ
ット濃縮度に上限値がある現在、天然ウランブランケッ
ト領域を設けると燃料集合体平均濃縮度が下がり、高燃
焼度化が難しくなる。(2) In order to achieve high burnup, it is necessary to increase the average enrichment of the fuel assembly. However, there is an upper limit to the pellet enrichment that can be used. The body average enrichment drops, making it difficult to achieve high burnup.
【０００９】本発明の目的は、天然ウランブランケット
を有する従来の燃料集合体に比べて、燃料経済性をほぼ
維持しつつ、取出燃焼度の増大及び熱的余裕の改善を実
現可能な燃料集合体を提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel assembly capable of realizing an increase in removal burn-up and an improvement in thermal margin while maintaining fuel economy substantially as compared with a conventional fuel assembly having a natural uranium blanket. Is to provide.
【００１０】[0010]
【課題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、核分裂性物質を含み可燃性毒物を含まな
い複数の第１燃料棒と、核分裂性物質及び可燃性毒物を
含む複数の第２燃料棒とを有する燃料集合体において、
前記燃料集合体は可燃性毒物を含まない領域を燃料有効
部の上端または下端の少なくとも一方に有し、該可燃性
毒物を含まない領域の横断面平均核分裂性物質濃度が
３.０ｗｔ％ 以下であり、前記可燃性毒物を含まない領
域のうち、上端または下端の少なくとも一方の領域の横
断面平均核分裂性物質濃度が０.７２ｗｔ％ 以上であ
り、ｅm を可燃性毒物を含む領域の平均核分裂性物質濃
度、ｅb を可燃性毒物を含まない領域の平均核分裂性物
質濃度、ｅn を天然ウランの平均核分裂性物質濃度とす
るとき、燃料有効部内に占める可燃性毒物を含まない領
域の軸方向長さの割合Ｌが、 Ｌ＜（ｅm−ｅn）／（１２（ｅm−ｅb）） の関係を満たすように構成する。In order to achieve the above object, the present invention comprises a plurality of first fuel rods containing fissile material and no burnable poison, and a plurality of first fuel rods containing fissile material and burnable poison. A fuel assembly having a second fuel rod of
The fuel assembly has a region containing no burnable poison at at least one of the upper end and the lower end of the active fuel portion, and the region not containing the burnable poison has an average fissile material concentration of 3.0 wt% or less. There, the one region that does not contain burnable poison, the cross-sectional mean fissile material concentration of at least one region of the upper or lower end is at least 0.72wt%, the average fission of the region containing the burnable poison the e m sex substance concentration, the average fissile material concentration in the region which does not contain burnable poison and e b, when the e n be the average fissile material concentration of natural uranium, the axis of the region not including the burnable poison occupying the fuel effective portion ratio L direction length, configured to satisfy the relationship of L <(e m -e n) / (12 (e m -e b)).
【００１１】従来の天然ウランブランケットを有する図
２に示すような燃料集合体の持つ課題を解決するため、
発明者らは図３に示すような燃料集合体を想定して上端
部又は下端部構造を見直し、これらの領域に可燃性毒物
を含まない濃縮ウラン燃料を使用するケースについて定
量的に検討した。その結果、以下の知見が得られた。 (１)熱的余裕は可燃性毒物を含まない領域である上下端
部の平均ウラン濃縮度を高めるにつれて向上する。図４
に示すように、軸方向出力ピーキングは、上下端部の平
均ウラン濃縮度が０.７ｗｔ％ から２.０ｗｔ％ になる
まで大きく減少し、上下端部の平均ウラン濃縮度をそれ
以上増加させても大きな変化は見られない。In order to solve the problem of the fuel assembly as shown in FIG. 2 having the conventional natural uranium blanket,
The inventors reviewed the structure of the upper end or lower end assuming a fuel assembly as shown in FIG. 3 and quantitatively examined the case where enriched uranium fuel containing no burnable poison was used in these regions. As a result, the following findings were obtained. (1) The thermal margin increases as the average uranium enrichment in the upper and lower ends, which is a region containing no burnable poison, is increased. FIG.
As shown in the figure, the axial output peaking greatly decreases the average uranium enrichment at the upper and lower ends from 0.7 wt% to 2.0 wt%, and further increases the average uranium enrichment at the upper and lower ends. No major change is seen.
【００１２】(２)反応度利得は可燃性毒物を含まない領
域である上下端部の平均ウラン濃縮度を高めるにつれて
減少傾向を示す。しかし、燃料集合体平均ウラン濃縮度
が４.０ｗｔ％ 程度の場合、図５に示すように、可燃性
毒物を含まない領域の平均ウラン濃縮度が２.０ｗｔ％
程度であれば反応度損失は比較的小さい。(2) The reactivity gain tends to decrease as the average uranium enrichment at the upper and lower ends, which is a region containing no burnable poison, is increased. However, when the average uranium enrichment of the fuel assembly is about 4.0 wt%, as shown in FIG. 5, the average uranium enrichment in the region not containing the burnable poison is 2.0 wt%.
To the extent the reactivity loss is relatively small.
【００１３】(３)貯蔵中の燃料集合体の未臨界度を確保
するため、燃料集合体の各横断面の冷温時中性子無限増
倍率は１.３ を上限に定められている。水対燃料体積比
が３程度の場合について、横断面平均濃縮度と無限増倍
率の関係を検討した結果、図６に示すように、横断面平
均濃縮度が３ｗｔ％ 以下であれば未臨界度を確保でき
ることがわかった。(3) In order to ensure the subcriticality of the fuel assembly during storage, the infinite multiplication factor of the neutron at the cold temperature of each cross section of the fuel assembly is set to 1.3 as an upper limit. As a result of examining the relationship between the average cross-sectional enrichment and the infinite multiplication factor when the water-to-fuel volume ratio is about 3, as shown in FIG. I found that I could secure.
【００１４】発明者らはこれらの新知見と、従来から知
られている２つの知見 (４)可燃性毒物を含まない領域に可燃性毒物を添加する
と反応度損失が生じる。 (５)燃料集合体平均濃縮度を増加させると取出燃焼度が
増加する。The inventors have found these new findings and two previously known findings. (4) If a burnable poison is added to a region containing no burnable poison, reactivity loss occurs. (5) Increasing the average enrichment of the fuel assembly increases the removal burnup.
【００１５】を踏まえ、本発明の燃料集合体構成が高燃
焼度化に有効であることを見出した。即ち、本発明の燃
料集合体を採用することにより、従来の燃料集合体に比
べて以下の５つの効果が得られる。Based on the above, it has been found that the fuel assembly configuration of the present invention is effective for increasing the burnup. That is, by employing the fuel assembly of the present invention, the following five effects can be obtained as compared with the conventional fuel assembly.
【００１６】(１)可燃性毒物を含まない領域である上端
部又は下端部の平均濃縮度を天然ウランの平均濃縮度よ
り高くすることにより、軸方向出力ピーキングを減少し
て熱的余裕を改善することができる。特に、上端部又は
下端部に対する平均濃縮度の下限値として１.４ｗｔ％
を適用すると、軸方向出力ピーキングの改善効果が大き
くなることが図４から読み取れる。(1) The average enrichment at the upper end or the lower end, which is a region containing no burnable poison, is higher than the average enrichment of natural uranium, thereby reducing axial output peaking and improving thermal margin. can do. In particular, the lower limit of the average concentration for the upper end or lower end is 1.4 wt%.
It can be seen from FIG. 4 that the effect of improving the output peaking in the axial direction is increased by applying.
【００１７】(２)上端部又は下端部の平均濃縮度を天然
ウランの平均濃縮度より高くすると、反応度利得は減少
傾向にあるが、横断面平均濃縮度が３ｗｔ％以下の範囲
においてはその損失は比較的小さい。(2) When the average enrichment at the upper end or the lower end is higher than the average enrichment of natural uranium, the reactivity gain tends to decrease, but when the average enrichment in the cross section is 3 wt% or less, the reactivity gain decreases. The losses are relatively small.
【００１８】(３)可燃性毒物が含まれない領域の横断面
平均濃縮度を３ｗｔ％以下とすることで、本発明の燃料
集合体の貯蔵中の未臨界度は確保される。(3) By setting the average cross-sectional enrichment of the region containing no burnable poison to 3 wt% or less, the subcriticality of the fuel assembly of the present invention during storage is ensured.
【００１９】(４)可燃性毒物を含まない上下端部を採用
しているため、この領域において可燃性毒物による反応
度損失がない。(4) Since the upper and lower ends which do not contain the burnable poison are employed, there is no loss of reactivity due to the burnable poison in this region.
【００２０】(５)以下に示すように、燃料有効長に占め
る可燃性毒物を含まない領域の長さの割合Ｌを数５の範
囲内に設定することにより、本発明の燃料集合体の平均
核分裂性物質濃度が従来の燃料集合体の平均核分裂性物
質濃度より大きくなるので、取出燃焼度を増大させるこ
とができる。(5) As shown below, by setting the ratio L of the length of the area not containing the burnable poison to the active fuel length within the range of Equation 5, the average of the fuel assembly of the present invention is obtained. Since the fissile material concentration is higher than the average fissile material concentration of the conventional fuel assembly, the output burnup can be increased.
【００２１】図２に示す従来の燃料集合体の平均核分裂
性物質濃度は、次式で表される。The average fissile material concentration of the conventional fuel assembly shown in FIG. 2 is expressed by the following equation.
【００２２】[0022]
【数１】 （２ｅn＋２２ｅm）／２４ …（数１） ここで、ｅm は中央部の平均核分裂性物質濃度、ｅn は
上下端部の天然ウランブランケットの平均核分裂性物質
濃度（＝０.７１１ｗｔ％ ）である。[Number 1] (2e n + 22e m) / 24 ... ( Equation 1) where, e m is the average fissile material concentration of the central portion, e n is the average fissile material concentration of natural uranium blanket upper and lower end portions (= 0.711 wt%).
【００２３】一方、図３に示す本発明の燃料集合体の可
燃性毒物を含まない領域の平均核分裂性物質濃度ｅb 及
び燃料有効長に占める長さの割合Ｌは、次式で表され
る。On the other hand, the ratio L length occupied in the average fissile material concentration e b and the active fuel length of the region not including the burnable poison in the fuel assembly of the present invention shown in FIG. 3 is expressed by the following formula .
【００２４】[0024]
【数２】 ｅb＝（ｅb1×Ｌ1＋ｅb2×Ｌ2）／（Ｌ1＋Ｌ2） Ｌ＝Ｌ1＋Ｌ2 …（数２） ここで、ｅb1及びｅb2は、それぞれ上端部及び下端部の
領域の平均核分裂性物質濃度である。[Number 2] e b = (e b1 × L 1 + e b2 × L 2) / (L 1 + L 2) L = L 1 + L 2 ... ( Equation 2) where, e b1 and e b2, respectively upper portion And the average fissile material concentration in the lower region.
【００２５】数２から、本発明の燃料集合体の平均核分
裂性物質濃度は、次式となる。From Equation 2, the average fissile material concentration of the fuel assembly of the present invention is as follows.
【００２６】[0026]
【数３】 （ｅb−ｅm)Ｌ＋ｅm …（数３） 数１及び数３から、本発明の燃料集合体の平均濃縮度が
図２の従来の燃料集合体の平均濃縮度より大きくなる条
件は、次式となる。From Equation 3] (e b -e m) L + e m ... ( Equation 3) Equations 1 and 3, the average enrichment of the fuel assembly of the present invention is greater than the average enrichment of the conventional fuel assembly of Figure 2 The condition is as follows.
【００２７】[0027]
【数４】 （２ｅn＋２２ｅm）／２４＜（ｅb−ｅm)Ｌ＋ｅm …（数４） 数４をＬについて解くことにより、Ｌの長さを制限する
次式が得られる。Equation 4] The (2e n + 22e m) / 24 <(e b -e m) L + e m ... ( Equation 4) Equation 4 by solving for L, the following equation to limit the length of L is obtained.
【００２８】[0028]
【数５】 Ｌ＜（ｅm−ｅn）／（１２（ｅm−ｅb）） …（数５） 以下、簡単のために、数５の右辺をＬ0 で表す。Equation 5] L <(e m -e n) / (12 (e m -e b)) ... ( 5) below, for the sake of simplicity, representing the right-hand side of Equation 5 in L 0.
【００２９】[0029]
【発明の実施の形態】以下、本発明の実施例を図１，図
７〜図１５を用いて説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
【００３０】（実施例１）図１は本発明の燃料集合体の
第１実施例として、燃料棒を９行９列に配置した燃料集
合体に本発明を適用した燃料集合体の水平（横）断面図
及び各燃料棒のウラン濃縮度とガドリニアの分布図であ
る。１０はガドリニアを含まない長尺の燃料棒、２０は
ガドリニアを含まない短尺燃料棒Ｐ、３０はガドリニア
入り燃料棒Ｇ１及びＧ２、４０は水ロッドＷ、５０はチ
ャンネルボックスをそれぞれ表している。また、図１の
下側の燃料棒内に付記されている数字はウラン濃縮度で
ある。最外周に燃料有効長の１１／２４の長さの４本の
短尺燃料棒を配置し、中央部には太径の２本の水ロッド
を配置してある。また、ガドリニア入り燃料棒の本数は
１６本である。(Embodiment 1) FIG. 1 shows a first embodiment of a fuel assembly according to the present invention, in which the present invention is applied to a fuel assembly in which fuel rods are arranged in 9 rows and 9 columns. 4) A sectional view and a distribution diagram of uranium enrichment and gadolinia of each fuel rod. Reference numeral 10 denotes a long fuel rod not containing gadolinia, 20 denotes a short fuel rod P not containing gadolinia, 30 denotes fuel rods G1 and G2 containing gadolinia, 40 denotes a water rod W, and 50 denotes a channel box. Further, the numeral added in the lower fuel rod of FIG. 1 is the uranium enrichment. Four short fuel rods having a length of 11/24 of the active fuel length are arranged at the outermost periphery, and two large diameter water rods are arranged at the center. The number of gadolinia-containing fuel rods is 16.
【００３１】図１は、図７の従来型の天然ウランブラン
ケットを使用した燃料集合体とは異なり、上端から燃料
有効長の１／２４の領域に本発明を適用している。即
ち、上下端の１／２４領域に可燃性毒物であるガドリニ
アを含まず、上端部の横断面平均濃縮度は２.１０ｗｔ
％、下端部の横断面平均濃縮度は０.７１ｗｔ％であ
り、いずれも３ｗｔ％ 以下である。また、上端部の横
断面平均濃縮度は０.７２wt％より大きい。中央部のガ
ドリニアを含む領域の平均濃縮度ｅm は４.４８ｗｔ
％、ガドリニアを含まない領域の平均濃縮度ｅb は１.
４ｗｔ％ であり、燃料有効長に占めるガドリニアを含
まない領域の長さの割合Ｌは２／２４＝０.０８ で、Ｌ
0 ＝０.１０より小さい。FIG. 1 differs from the conventional fuel assembly using a natural uranium blanket of FIG. 7 in that the present invention is applied to a region 1/24 of the active fuel length from the upper end. That is, gadolinia, which is a burnable poison, is not included in the upper and lower 1/24 regions, and the average cross-sectional concentration of the upper end is 2.10 wt.
%, And the average concentration of the cross section at the lower end is 0.71 wt%, all of which are 3 wt% or less. Also, the average cross-sectional enrichment at the upper end is greater than 0.72 wt%. Average enrichment e m area including the gadolinia in the central portion 4.48wt
%, The average enrichment e b a region containing no gadolinia 1.
4% by weight, and the ratio L of the length of the region not including gadolinia to the active fuel length is 2/24 = 0.08.
0 = less than 0.10.
【００３２】この燃料集合体では、水ギャップに隣接す
る最外周に高濃縮度ペレット（１〜４）を、他の部分に
天然ウランペレットを使用して本発明の断面構造を実現
している。本実施例による効果を解析により調べた結
果、図７の従来の燃料集合体と比べて、上端部出力が増
大することによる軸方向出力ピーキングの改善効果が約
１.５％ 、燃料集合体平均濃縮度が高まることによる燃
料集合体の取出燃焼度の増大が約０.７ＧＷｄ／ｔ であ
ることが判った。In this fuel assembly, the cross-sectional structure of the present invention is realized by using high-enrichment pellets (1 to 4) at the outermost periphery adjacent to the water gap and using natural uranium pellets at other portions. As a result of analyzing the effect of the present embodiment by analysis, the improvement effect of the axial output peaking due to the increase of the upper end output was about 1.5% compared with the conventional fuel assembly of FIG. It was found that the increase in the removal burnup of the fuel assembly due to the increase in the enrichment was about 0.7 GWd / t.
【００３３】（実施例２）図８は、図１と同じ燃料配列
の燃料集合体に対する第２実施例である。先程の実施例
と同様に、本発明の要件について考える。上下端の１／
２４領域に可燃性毒物であるガドリニアを含まず、上端
部の横断面平均濃縮度は２.２７ｗｔ％ 、下端部の横断
面平均濃縮度は０.７１ｗｔ％ であり、いずれも３ｗｔ
％以下である。また、上端部の横断面平均濃縮度は０.
７２ｗｔ％ より大きい。中央部のガドリニアを含む領
域の平均濃縮度ｅm は４.４８ｗｔ％ 、ガドリニアを含
まない領域の平均濃縮度ｅb は１.５ｗｔ％ であり、燃
料有効長に占めるガドリニアを含まない領域の長さの割
合Ｌは２／２４＝０.０８で、Ｌ0 ＝０.１１より小さ
い。よって、この実施例は全ての要件を満たしている。(Embodiment 2) FIG. 8 shows a second embodiment for a fuel assembly having the same fuel arrangement as in FIG. As with the previous embodiment, the requirements of the present invention are considered. Upper / lower 1 /
The gadolinia, which is a burnable poison, is not included in the 24 regions, the average cross-sectional concentration at the upper end is 2.27 wt%, and the average cross-sectional concentration at the lower end is 0.71 wt%, all of which are 3 wt%.
% Or less. In addition, the average cross-sectional enrichment at the upper end is 0.1.
Greater than 72 wt%. The average enrichment e m is 4.48Wt% of the region containing the gadolinia in the central portion, the average enrichment e b a region not containing gadolinia is 1.5 wt%, the length of the region not including the gadolinia occupying the fuel effective length The ratio L is 2/24 = 0.08, which is smaller than L 0 = 0.11. Therefore, this embodiment satisfies all the requirements.
【００３４】また、図１では最外周に高濃縮燃料を配置
していたのに対し、本実施例ではその逆の構造、すなわ
ち最外周付近に低濃縮燃料（１〜４）を用いて本発明の
構造を実現している点が図１との相違点である。この断
面構造は、水ギャップ近傍の熱中性子の多い領域に低濃
縮燃料を配しているため反応度損失は大きくなるが、燃
料集合体の水平方向の出力分布は図１に比べて平坦化さ
れるので、上端から燃料有効長の１／２４の領域の横断
面における局所出力ピーキングを図１に比べて低減する
ことが可能である。In FIG. 1, the highly enriched fuel is disposed at the outermost periphery, whereas in the present embodiment, the reverse structure is adopted, that is, the present invention uses the low enriched fuel (1 to 4) near the outermost periphery. 1 is different from FIG. In this cross-sectional structure, the reactivity loss is increased because the low-enriched fuel is disposed in the region with a large amount of thermal neutrons near the water gap, but the horizontal power distribution of the fuel assembly is flattened as compared to FIG. Therefore, it is possible to reduce the local output peaking in the cross section of the area of 1/24 of the active fuel length from the upper end as compared with FIG.
【００３５】図１の実施例と比較したときの図８の実施
例の効果として、上端部出力が低下することによる軸方
向出力ピーキングの増大、上端部横断面の水平方向出力
の平坦化による局所出力ピーキングの低下、反応度損失
の増大による燃料経済性の低下が得られる。また、図７
に示した従来型の燃料集合体に比べれば、軸方向出力ピ
ーキングを約１.０％改善、取出燃焼度を約０.６ＧＷｄ
／ｔ増大することができる。The advantages of the embodiment of FIG. 8 when compared to the embodiment of FIG. 1 include an increase in axial output peaking due to a decrease in output at the top, and a localization due to the flattening of the horizontal output of the top cross section. A reduction in output peaking and a decrease in fuel economy due to an increase in reactivity loss are obtained. FIG.
The axial output peaking is improved by about 1.0% and the output burn-up is about 0.6 GWd compared to the conventional fuel assembly shown in FIG.
/ T can be increased.
【００３６】（実施例３）図９は本発明の構造を、燃料
棒を９行９列に配置した燃料集合体に適用した第３実施
例である。最外周から１層内側に燃料有効長の１４／２
４の長さの８本の短尺燃料棒Ｐを配置し、中央部には太
径の２本の水ロッドＷを配置してある。また、ガドリニ
ア入り燃料棒Ｇ１及びＧ２の本数は１６本である。先程
の実施例とはガドリニア入り燃料棒の配置、短尺燃料棒
の配置及び軸方向長さなど、構成が大きく異なってい
る。この燃料集合体の平均濃縮度は約３.９４ｗｔ％ で
ある。この燃料集合体は以下に示すように本発明の要件
を満たしている。即ち、上下端の１／２４領域に可燃性
毒物であるガドリニアを含まず、上端部の横断面平均濃
縮度は２.００ｗｔ％、下端部の横断面平均濃縮度は０.
７１ｗｔ％であり、いずれも３ｗｔ％ 以下である。ま
た、上端部の横断面平均濃縮度は０.７２ｗｔ％より大
きい。中央部のガドリニアを含む領域の平均濃縮度ｅm
は４.１５ｗｔ％、ガドリニアを含まない領域の平均濃
縮度ｅbは１.３６ｗｔ％であり、燃料有効長に占めるガ
ドリニアを含まない領域の長さの割合Ｌは２／２４＝
０.０８ で、Ｌ0＝０.１０ より小さい。(Embodiment 3) FIG. 9 shows a third embodiment in which the structure of the present invention is applied to a fuel assembly having fuel rods arranged in 9 rows and 9 columns. 14/2 of active fuel length inside one layer from outermost circumference
Eight short fuel rods P having a length of 4 are arranged, and two large-diameter water rods W are arranged at the center. The number of gadolinia-containing fuel rods G1 and G2 is 16. The configuration is greatly different from the previous embodiment, such as the arrangement of gadolinia-containing fuel rods, the arrangement of short fuel rods, and the axial length. The average enrichment of this fuel assembly is about 3.94 wt%. This fuel assembly satisfies the requirements of the present invention as described below. That is, gadolinia, which is a burnable poison, is not contained in the upper and lower 1/24 regions, the average cross-sectional enrichment at the upper end is 2.00 wt%, and the average cross-sectional enrichment at the lower end is 0.000%.
It is 71 wt%, and all are 3 wt% or less. Also, the average cross-sectional enrichment at the upper end is greater than 0.72 wt%. Average enrichment e m area including the gadolinia in the central portion
Is 4.15wt%, average enrichment e b a region containing no gadolinia is 1.36wt%, the ratio of the length of the region not including the gadolinia occupying the fuel effective length L 2/24 =
0.08, which is smaller than L 0 = 0.10.
【００３７】この燃料集合体を、図９の上端部の濃縮度
２.０ｗｔ％ の燃料を天然ウランブランケットに置き換
えた従来の燃料集合体と比較すると、上端部出力上昇に
よる軸方向出力ピーキングの低減効果が約１.５％ 、燃
料集合体平均濃縮度の増加による取出燃焼度の増大が約
０.７ＧＷｄ／ｔ であることが解析により求まった。即
ち、先程の２つの実施例のように天然ウランペレットと
高濃縮度ペレットを混在させることによって本発明の構
造を実現することも、図９のように、上端部又は下端部
の横断面を一様な濃縮度ペレットで構成することによっ
て本発明の構造を実現することも可能である。When this fuel assembly is compared with a conventional fuel assembly in which the enrichment 2.0 wt% fuel at the upper end in FIG. 9 is replaced with a natural uranium blanket, the reduction in the axial output peaking due to the increase in the output at the upper end. It was determined by analysis that the effect was about 1.5% and the increase in withdrawal burnup due to an increase in the average enrichment of the fuel assembly was about 0.7 GWd / t. That is, the structure of the present invention can be realized by mixing natural uranium pellets and high-enrichment pellets as in the previous two embodiments, or as shown in FIG. It is also possible to realize the structure of the present invention by using pellets having such a high concentration.
【００３８】（実施例４）図１０は、本発明の構造を９
行９列の燃料棒配列を有し、方形の水ロッドを備えた燃
料集合体に適用した第４実施例である。短尺燃料棒は使
用していない。ガドリニア入り燃料棒Ｇ１及びＧ２は１
６本配置されており、うち８本のＧ１は軸方向にガドリ
ニア濃縮度分布を有している。この燃料集合体は以下に
示すように本発明の要件を満たしている。即ち、上下端
の１／２４領域に可燃性毒物であるガドリニアを含ま
ず、上端部の横断面平均濃縮度は０.７１ｗｔ％ 、下端
部の横断面平均濃縮度は２.２７ｗｔ％ であり、いずれ
も３ｗｔ％以下である。また、下端部の横断面平均濃縮
度は０.７２ｗｔ％ より大きい。中央部のガドリニアを
含む領域の平均濃縮度ｅm は４.３７ｗｔ％ 、ガドリニ
アを含まない領域の平均濃縮度ｅb は１.４９ｗｔ％ で
あり、燃料有効長に占めるガドリニアを含まない領域の
長さの割合Ｌは２／２４＝０.０８ で、Ｌ0＝０.１１よ
り小さい。(Embodiment 4) FIG. 10 shows the structure of the present invention as 9
It is a fourth embodiment applied to a fuel assembly having a fuel rod array of 9 rows and a rectangular water rod. No short fuel rods were used. Gadolinia containing fuel rods G1 and G2 are 1
Six of them are arranged, and eight of them G1 have a gadolinia enrichment distribution in the axial direction. This fuel assembly satisfies the requirements of the present invention as described below. That is, gadolinia, which is a combustible poison, is not contained in the upper and lower 1/24 regions, the average cross-sectional enrichment at the upper end is 0.71 wt%, and the average cross-sectional enrichment at the lower end is 2.27 wt%. All are 3 wt% or less. In addition, the average cross-sectional concentration at the lower end is greater than 0.72 wt%. The average enrichment e m is 4.37Wt% of the region containing the gadolinia in the central portion, the average enrichment e b a region not containing gadolinia is 1.49Wt%, the length of the region not including the gadolinia occupying the fuel effective length The ratio L is 2/24 = 0.08, which is smaller than L 0 = 0.11.
【００３９】本実施例では上端ではなく下端に本発明を
採用している。沸騰水型原子炉は軸方向のボイド分布と
出力分布が互いに関係しているため、一般に水の密度の
大きい炉心下部の出力は上部の出力より大きくなる。そ
のため、下端部に本発明を適用した本実施例では軸方向
出力ピーキングの平坦化効果は上端部に適用したときに
比べて小さくなる。しかし、図１１に示す従来の燃料集
合体に比べれば、軸方向出力ピーキングの低減（約１.
０％）、取出燃焼度の増大(約０.６ＧＷｄ／ｔ)が得ら
れるので、燃料集合体平均濃縮度を高めて取出燃焼度を
高めたいときには、本実施例のように下端部に本発明の
構造を採用することも可能である。In the present embodiment, the present invention is adopted not at the upper end but at the lower end. In a boiling water reactor, the power distribution in the lower part of the core where the density of water is large is generally larger than the power in the upper part, since the axial void distribution and the power distribution are related to each other. Therefore, in the present embodiment in which the present invention is applied to the lower end, the flattening effect of the axial output peaking is smaller than when applied to the upper end. However, compared to the conventional fuel assembly shown in FIG. 11, the axial output peaking was reduced (about 1.
0%) and an increase in the output burnup (about 0.6 GWd / t). Therefore, when it is desired to increase the average enrichment of the fuel assembly to increase the output burnup, the present invention is applied to the lower end portion as in this embodiment. It is also possible to adopt the structure of FIG.
【００４０】（実施例５）図１２は、本発明の構造を、
燃料棒を１０行１０列に配置した燃料集合体に採用した
第５実施例である。燃料集合体中央部に太径の水ロッド
Ｗを２本使用しており、ガドリニア入り燃料棒Ｇ１及び
Ｇ２は１６本、短尺燃料棒Ｐは燃料有効長の１４／２４
の長さのものが１４本配置されている。図１２の燃料集
合体平均濃縮度は約４.２３ｗｔ％ である。(Embodiment 5) FIG. 12 shows the structure of the present invention.
This is a fifth embodiment in which fuel rods are arranged in 10 rows and 10 columns and are used in a fuel assembly. Two large-diameter water rods W are used in the center of the fuel assembly, 16 gadolinia-containing fuel rods G1 and G2, and the short fuel rod P are 14/24 of the active fuel length.
Are arranged. The average enrichment of the fuel assembly in FIG. 12 is about 4.23 wt%.
【００４１】また、この燃料集合体は以下に示すように
本発明の要件を満たしている。即ち、上端の２／２４領
域と下端の１／２４領域に可燃性毒物であるガドリニア
を含まず、上端部及び下端部の横断面平均濃縮度は双方
ともに２.３８ｗｔ％ であり、いずれも３ｗｔ％以下で
ある。また、上端部及び下端部の横断面平均濃縮度が
０.７２ｗｔ％ より大きい。中央部のガドリニアを含む
領域の平均濃縮度ｅm は４.５５ｗｔ％ 、ガドリニアを
含まない領域の平均濃縮度ｅbは２.３８ｗｔ％であり、
燃料有効長に占めるガドリニアを含まない領域の長さの
割合Ｌは３／２４＝０.１２５で、Ｌ0 ＝０.１５より小
さい。The fuel assembly satisfies the requirements of the present invention as described below. That is, gadolinia, which is a burnable poison, is not included in the 2/24 region at the upper end and the 1/24 region at the lower end, and the average cross-sectional enrichment at both the upper and lower ends is 2.38 wt%, and both are 3 wt%. % Or less. Also, the average cross-sectional enrichment at the upper end and lower end is greater than 0.72 wt%. The average enrichment e m is 4.55Wt% of the region containing the gadolinia in the central portion, the average enrichment e b a region not containing gadolinia is 2.38 wt%,
The ratio L of the length of the region not including gadolinia to the active fuel length is 3/24 = 0.125, which is smaller than L 0 = 0.15.
【００４２】このような１０行１０列の燃料配置を持つ
燃料集合体であっても、図１３に示す従来型の燃料集合
体に比べて、端部出力の上昇及び燃料集合体の平均濃縮
度の増加が起こるため、９行９列の燃料棒配列を持つ燃
料集合体と同様の作用により本発明の効果が得られる。
本実施例では、上端から２／２４及び下端から１／２４
の領域に本発明を採用することにより、上端部及び下端
部の反応度を同時に向上させて軸方向出力分布を大きく
平坦化すると同時に、燃料集合体の平均濃縮度の上昇に
より取出燃焼度を大きく改善することが可能である。具
体的には、軸方向出力ピーキングにして約２.０ｗｔ％
の低減、取出燃焼度にして約１.４GWd／ｔの増大とな
る。Even with such a fuel assembly having a fuel arrangement of 10 rows and 10 columns, the end output is increased and the average enrichment of the fuel assembly is higher than that of the conventional fuel assembly shown in FIG. Therefore, the effect of the present invention can be obtained by the same operation as a fuel assembly having a 9 × 9 fuel rod array.
In this embodiment, 2/24 from the upper end and 1/24 from the lower end.
By adopting the present invention in the region, the reactivity of the upper end portion and the lower end portion are simultaneously improved to greatly flatten the axial power distribution, and at the same time, the extraction burnup is increased by increasing the average enrichment of the fuel assembly. It is possible to improve. Specifically, the axial output peaking is about 2.0 wt%
And the removal burnup increases by about 1.4 GWd / t.
【００４３】（実施例６）図１４は、本発明の構造を方
形の水ロッド１本を有する１０行１０列の燃料棒配列の
燃料集合体に適用した第６実施例である。ガドリニア入
り燃料棒Ｇ１及びＧ２は１６本、短尺燃料棒Ｐは燃料有
効長の１４／２４の長さのものが１２本配置されてい
る。この実施例では、燃料集合体の上下端に対して天然
ウランブランケットの替わりに劣化ウランを使用してい
るのが特徴である。燃料集合体の平均濃縮度は４.２９
ｗｔ％ である。(Embodiment 6) FIG. 14 shows a sixth embodiment in which the structure of the present invention is applied to a fuel assembly having a 10-row, 10-column fuel rod array having one rectangular water rod. Sixteen gadolinia-containing fuel rods G1 and G2 are arranged, and twelve short fuel rods P having a length of 14/24 of the active fuel length are arranged. This embodiment is characterized in that depleted uranium is used for the upper and lower ends of the fuel assembly instead of the natural uranium blanket. The average enrichment of the fuel assembly is 4.29
wt%.
【００４４】この燃料集合体は以下に示すように本発明
の要件を満たしている。即ち、上下端の１／２４領域に
可燃性毒物であるガドリニアを含まず、上端部の横断面
平均濃縮度は２.０８ｗｔ％、下端部の横断面平均濃縮
度は０.２０ｗｔ％であり、いずれも３ｗｔ％以下であ
る。また、上端部の横断面平均濃縮度は０.７２ｗｔ％
より大きい。中央部のガドリニアを含む領域の平均濃縮
度ｅm は４.５５ｗｔ％、ガドリニアを含まない領域の
平均濃縮度ｅb は１.１４ｗｔ％ であり、燃料有効長に
占めるガドリニアを含まない領域の長さの割合Ｌは２／
２４＝０.０８ で、Ｌ0＝０.０９より小さい。This fuel assembly satisfies the requirements of the present invention as described below. That is, gadolinia, which is a burnable poison, is not included in the upper and lower 1/24 regions, the average cross-sectional concentration of the upper end is 2.08 wt%, and the average cross-sectional concentration of the lower end is 0.20 wt%. All are 3 wt% or less. The average cross-sectional concentration of the upper end is 0.72 wt%.
Greater than. The average enrichment e m is 4.55Wt% of the region containing the gadolinia in the central portion, the average enrichment e b a region not containing gadolinia is 1.14Wt%, the length of the region not including the gadolinia occupying the fuel effective length The ratio L is 2 /
24 = 0.08, which is smaller than L 0 = 0.09.
【００４５】劣化ウランを使用しているために端部の出
力が小さく、軸方向の出力ピーキングは天然ウランを用
いた場合に比べて厳しくなるが、本実施例の横断面は平
均濃縮度として０.７２ｗｔ％ を超えるものとなるた
め、図１５に示す天然ウランブランケットを採用した燃
料集合体と比べても軸方向出力ピーキングは改善され
る。この結果、軸方向出力ピーキングが約１％、取出燃
焼度が約０.８ＧＷｄ／ｔ改善される。The use of depleted uranium has a small output at the end, and the output peaking in the axial direction is stricter than when natural uranium is used. However, the cross section of this embodiment has an average enrichment of 0%. Since it exceeds 0.72 wt%, the axial output peaking is improved even in comparison with the fuel assembly employing the natural uranium blanket shown in FIG. As a result, the axial output peaking is improved by about 1%, and the discharge burnup is improved by about 0.8 GWd / t.
【００４６】以上、６つの実施例を用いて説明したよう
に、本発明は、燃料集合体中の燃料棒の配列や水ロッド
の形状など燃料集合体の水平断面（横断面）構造によら
ず、軸方向のガドリニア分布や濃縮度分布、及び燃料集
合体平均濃縮度にその本質があることがわかる。As described above with reference to the six embodiments, the present invention is not limited to the horizontal cross-sectional (cross-sectional) structure of the fuel assembly such as the arrangement of the fuel rods in the fuel assembly and the shape of the water rod. It can be seen that the gadolinia distribution and enrichment distribution in the axial direction and the average enrichment of the fuel assembly have their essence.
【００４７】[0047]
【発明の効果】本発明によれば、従来の燃料集合体に比
べて、燃料経済性をほぼ維持しつつ、軸方向出力ピーキ
ングを低減し且つ取出燃焼度を増大させることが可能で
ある。According to the present invention, it is possible to reduce the axial output peaking and increase the take-up burnup while maintaining the fuel economy substantially as compared with the conventional fuel assembly.
【図１】本発明の燃料集合体の第１実施例を示す図。FIG. 1 is a view showing a first embodiment of a fuel assembly according to the present invention.
【図２】従来の軸方向濃縮度分布の概念図。FIG. 2 is a conceptual diagram of a conventional axial enrichment distribution.
【図３】本発明の軸方向濃縮度分布の概念図。FIG. 3 is a conceptual diagram of the axial enrichment distribution of the present invention.
【図４】可燃性毒物を含まない領域の横断面平均濃縮度
と軸方向出力ピーキングの関係図。FIG. 4 is a graph showing the relationship between the average cross-sectional enrichment of a region containing no burnable poison and the axial output peaking.
【図５】可燃性毒物を含まない領域の横断面平均濃縮度
と増倍率利得の関係図。FIG. 5 is a diagram showing the relationship between the average cross-sectional enrichment and the multiplication gain in a region containing no burnable poison.
【図６】可燃性毒物を含まない領域の横断面平均濃縮度
と中性子無限増倍率の関係図。FIG. 6 is a graph showing the relationship between the average cross-sectional enrichment of a region containing no burnable poison and the neutron infinite multiplication factor.
【図７】第１実施例及び第２実施例の比較例を示す図。FIG. 7 is a diagram showing a comparative example of the first embodiment and the second embodiment.
【図８】本発明の燃料集合体の第２実施例を示す図。FIG. 8 is a view showing a second embodiment of the fuel assembly of the present invention.
【図９】本発明の燃料集合体の第３実施例を示す図。FIG. 9 is a view showing a third embodiment of the fuel assembly of the present invention.
【図１０】本発明の燃料集合体の第４実施例を示す図。FIG. 10 is a view showing a fourth embodiment of the fuel assembly of the present invention.
【図１１】第４実施例の比較例を示す図。FIG. 11 is a diagram showing a comparative example of the fourth embodiment.
【図１２】本発明の燃料集合体の第５実施例を示す図。FIG. 12 is a view showing a fifth embodiment of the fuel assembly according to the present invention.
【図１３】第５実施例の比較例を示す図。FIG. 13 is a diagram showing a comparative example of the fifth embodiment.
【図１４】本発明の燃料集合体の第６実施例を示す図。FIG. 14 is a view showing a sixth embodiment of the fuel assembly of the present invention.
【図１５】第６実施例の比較例を示す図。FIG. 15 is a diagram showing a comparative example of the sixth embodiment.
１０…燃料棒、２０…短尺燃料棒、３０…ガドリニア入
り燃料棒、４０…水ロッド、５０…チャンネルボック
ス。10: fuel rod, 20: short fuel rod, 30: fuel rod containing gadolinia, 40: water rod, 50: channel box.
フロントページの続き (72)発明者 配川 勝正 茨城県日立市幸町三丁目１番１号 株式会 社日立製作所日立工場内Continued on the front page (72) Inventor Katsumasa Narikawa 3-1-1, Sachimachi, Hitachi City, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant
Claims (6)
複数の第１燃料棒と、核分裂性物質及び可燃性毒物を含
む複数の第２燃料棒とを有する燃料集合体において、 前記燃料集合体は可燃性毒物を含まない領域を燃料有効
部の上端または下端の少なくとも一方に有し、該可燃性
毒物を含まない領域の横断面平均核分裂性物質濃度が
３.０ｗｔ％ 以下であり、 前記可燃性毒物を含まない領域のうち、上端または下端
の少なくとも一方の領域の横断面平均核分裂性物質濃度
が０.７２ｗｔ％ 以上であり、 ｅm を可燃性毒物を含む領域の平均核分裂性物質濃度、
ｅb を可燃性毒物を含まない領域の平均核分裂性物質濃
度、ｅn を天然ウランの平均核分裂性物質濃度とすると
き、燃料有効部内に占める可燃性毒物を含まない領域の
軸方向長さの割合Ｌが、 Ｌ＜（ｅm−ｅn）／（１２（ｅm−ｅb）） の関係を満たすことを特徴とする燃料集合体。1. A fuel assembly comprising: a plurality of first fuel rods containing fissile material and no burnable poison; and a plurality of second fuel rods containing fissile material and burnable poison. The body has a region containing no burnable poison at at least one of the upper end and the lower end of the active fuel portion, and the region not containing the burnable poison has an average cross-sectional fissile material concentration of 3.0 wt% or less; in the region that does not contain burnable poison, the cross-sectional mean fissile material concentration of at least one region of the upper or lower end is at least 0.72wt%, the average fissile material concentration of the region containing the burnable poison the e m ,
The average fissile material concentration in the region that does not include e b a burnable poison, when the e n be the average fissile material concentration of natural uranium, the region not including the burnable poison occupying the fuel effective portion axial length of the ratio L is, L <(e m -e n ) / (12 (e m -e b)) the fuel assembly characterized by satisfying the relationship.
端または下端の少なくとも一方の領域の横断面平均核分
裂性物質濃度が１.４ｗｔ％ 以上であることを特徴とす
る請求項１記載の燃料集合体。2. The average fissile substance concentration in a cross section of at least one of an upper end and a lower end of the region not containing the burnable poison is 1.4 wt% or more. Fuel assembly.
４.０ｗｔ％ 以上であることを特徴とする請求項１また
は請求項２記載の燃料集合体。3. The fuel assembly according to claim 1, wherein the average fissile material concentration of the fuel assembly is 4.0 wt% or more.
配置されていることを特徴とする請求項１乃至請求項３
の何れかに記載の燃料集合体。4. The fuel rod according to claim 1, wherein the fuel rods are arranged in a square lattice of 9 rows and 9 columns or more.
The fuel assembly according to any one of the above.
ウランペレットが含まれていることを特徴とする請求項
４に記載の燃料集合体。5. The fuel assembly according to claim 4, wherein the region containing no burnable poison contains natural uranium pellets.
均核分裂性物質濃度が等しいことを特徴とする請求項４
または請求項５記載の燃料集合体。6. A cross-sectional average fissile material concentration in a region containing no burnable poison is equal to that in the region.
Or the fuel assembly according to claim 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13319797A JP3262022B2 (en) | 1997-05-23 | 1997-05-23 | Fuel assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13319797A JP3262022B2 (en) | 1997-05-23 | 1997-05-23 | Fuel assembly |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10325890A true JPH10325890A (en) | 1998-12-08 |
| JP3262022B2 JP3262022B2 (en) | 2002-03-04 |
Family
ID=15098996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13319797A Expired - Fee Related JP3262022B2 (en) | 1997-05-23 | 1997-05-23 | Fuel assembly |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3262022B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001024196A1 (en) * | 1999-09-29 | 2001-04-05 | Hitachi, Ltd. | Fuel assembly |
| US6735267B2 (en) | 2001-12-28 | 2004-05-11 | Hitachi, Ltd. | Fuel assembly |
| JP2016138767A (en) * | 2015-01-26 | 2016-08-04 | 原子燃料工業株式会社 | Fuel assembly and reactor core |
-
1997
- 1997-05-23 JP JP13319797A patent/JP3262022B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001024196A1 (en) * | 1999-09-29 | 2001-04-05 | Hitachi, Ltd. | Fuel assembly |
| US6735267B2 (en) | 2001-12-28 | 2004-05-11 | Hitachi, Ltd. | Fuel assembly |
| JP2016138767A (en) * | 2015-01-26 | 2016-08-04 | 原子燃料工業株式会社 | Fuel assembly and reactor core |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3262022B2 (en) | 2002-03-04 |
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