JP2737350B2 - Nuclear fuel pellets - Google Patents
Nuclear fuel pelletsInfo
- Publication number
- JP2737350B2 JP2737350B2 JP2048240A JP4824090A JP2737350B2 JP 2737350 B2 JP2737350 B2 JP 2737350B2 JP 2048240 A JP2048240 A JP 2048240A JP 4824090 A JP4824090 A JP 4824090A JP 2737350 B2 JP2737350 B2 JP 2737350B2
- Authority
- JP
- Japan
- Prior art keywords
- pores
- powder
- nuclear fuel
- gas
- pellet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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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
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- Inert Electrodes (AREA)
- Ceramic Products (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 本発明は、照射時における核***生成ガスの保持力に
優れた核燃料ペレットに関する。Description: FIELD OF THE INVENTION The present invention relates to nuclear fuel pellets having excellent fission gas retention during irradiation.
「従来の技術」 最近、原子炉燃料をより長時間使用する、いわゆる高
燃度化計画が検討されているが、その実現に際しては、
核燃料が発生する核***生成ガス（FPガス）を核燃料ペ
レットの外にできるだけ放出しないようにすることが肝
要である。"Conventional technology" Recently, a so-called high flammability plan, which uses reactor fuel for a longer time, is being studied.
It is important that the fission product gas (FP gas) generated by nuclear fuel be released as little as possible out of the nuclear fuel pellets.
FPガスがペレット外に放出される機構は一般に次のよ
うに考えられている。まず、ペレットの結晶粒内でFPガ
スが発生し、このガスが結晶粒子あるいは結晶粒界で気
泡を形成する。このうち、粒界において生成した気泡が
ある程度の量に達すると、ついには粒界に沿ってトンネ
ルが形成され、このトンネルを通って粒界に存在するFP
ガスがペレット外に放出される。The mechanism by which FP gas is released outside the pellet is generally considered as follows. First, FP gas is generated in the crystal grains of the pellet, and this gas forms bubbles at crystal grains or crystal grain boundaries. Of these, when the amount of bubbles generated at the grain boundary reaches a certain amount, a tunnel is formed along the grain boundary, and FP existing at the grain boundary through this tunnel
Gas is released out of the pellet.
このことから、FPガスの発生そのものを抑えることは
できないとしても、焼結体ペレット中の結晶粒径を大き
くし、結晶粒内で生成したFPガスの粒界への到達距離を
長くすることにより、ペレット内にガスを閉じ込めて、
結果的にFPガスの放出量が低減できると考えられる。こ
のため高燃焼度用核燃料として、結晶粒径の大きいペレ
ットを使用する考えが一般的になりつつある。最適な結
晶粒径については未だ明らかでないが、本出願者が行な
った燃焼度およびFPガス放出率等の検討によれば、20μ
ｍ以上が好適であると考えられる。From this, even if it is not possible to suppress the generation of FP gas itself, by increasing the crystal grain size in the sintered compact pellet and increasing the reach of the FP gas generated within the crystal grain to the grain boundary, , Trap the gas in the pellet,
As a result, it is considered that the emission amount of the FP gas can be reduced. For this reason, the idea of using pellets having a large crystal grain size as the nuclear fuel for high burnup is becoming common. Although the optimal crystal grain size has not been clarified yet, according to the study of the burnup and the FP gas emission rate performed by the present applicant, it was found that
m or more is considered suitable.
従来行なわれている大粒径ペレットの製造方法として
は、原料のUO2粉末にニオビア（Nb2O5）等を添加する方
法や、圧粉成形体をCO2等の酸化性雰囲気中で焼結する
方法、原料として結晶粒成長速度の大きい高活性UO2粉
末を用いる方法等が既に提案されている。Conventional methods for producing large-diameter pellets include adding Niovia (Nb 2 O 5 ) or the like to the raw UO 2 powder or firing a green compact in an oxidizing atmosphere such as CO 2. There have already been proposed a method of sintering, a method of using highly active UO 2 powder having a high crystal grain growth rate as a raw material, and the like.
しかし、添加物を使用する方法では、核燃料ペレット
の融点等の物性に対する影響が必ずしも明らかではな
く、また、酸化性雰囲気中で焼結する方法では製造方法
が非常に繁雑でコストがかかる等の問題を有する。この
ため、高活性UO2粉末を原料としてペレットを形成する
方法が最も問題が少ない。この観点から、本出願人らは
先に、特願昭61−142506号、特開昭61−190079号、特願
昭63−127934号、特願昭63−127935号および米国特許出
願第139447号において、高活性UO2粉末を用いた大粒径
ペレットの製造方法を提案してきた。However, in the method using additives, the influence on the physical properties such as the melting point of nuclear fuel pellets is not always clear, and in the method of sintering in an oxidizing atmosphere, the production method is very complicated and costly. Having. For this reason, the method of forming pellets using highly active UO 2 powder as a raw material has the fewest problems. From this viewpoint, the present applicants have previously disclosed Japanese Patent Application No. 61-142506, Japanese Patent Application Laid-Open No. 61-190079, Japanese Patent Application No. 63-127934, Japanese Patent Application No. 63-127935, and U.S. Pat. Has proposed a method for producing large-diameter pellets using highly active UO 2 powder.
ところが、このような高活性UO2粉末を原料として核
燃料ペレットを製造すると、結晶粒径が大きくなるとと
もに、副次的な効果として焼結密度が所望値よりも高く
なることが確認された。結晶密度は、製品ペレットの規
格によって94〜97％TDと定められており、この規格を越
えては不都合が生じる。However, it was confirmed that when nuclear fuel pellets were produced using such a highly active UO 2 powder as a raw material, the crystal grain size was increased, and as a secondary effect, the sintered density was higher than a desired value. The crystal density is determined to be 94 to 97% TD according to the product pellet standard, and inconvenience occurs beyond this standard.
そこで、高活性粉末を用いた場合に焼結密度が高くな
りすぎることを防ぐために、本出願人は特願昭63−3303
40号において、シュウ酸アンモニウム等のポアフォーマ
ーを原料粉末に添加し、核燃料ペレットの組織中に気孔
を発生させて、大粒径化に伴う焼結密度の上昇を相殺す
る方法を提案した。In order to prevent the sintering density from becoming too high when a highly active powder is used, the present applicant has filed Japanese Patent Application No. 63-3303.
In No. 40, a method was proposed in which a pore former such as ammonium oxalate was added to the raw material powder to generate pores in the structure of the nuclear fuel pellet, thereby offsetting the increase in sintering density accompanying the increase in grain size.
「発明が解決しようとする課題」 ところで、前述したFPガス放出機構から判断して、こ
の種の気孔は結晶粒界に存在するよりも、結晶粒内に独
立して存在する方が望ましいと考えられる。すなわち、
結晶粒内の独立気孔はFPガスを有効に閉じ込める機能を
持つが、粒界にある気孔はトンネルの役目を果たし、逆
にFPガス放出を促進することになるからである。"Problems to be Solved by the Invention" By the way, judging from the FP gas release mechanism described above, it is considered that it is preferable that such pores exist independently in the crystal grains rather than in the crystal grain boundaries. Can be That is,
The independent pores in the crystal grains have the function of effectively confining the FP gas, but the pores at the grain boundaries serve as a tunnel, which in turn promotes the release of the FP gas.
この観点から、前述のポアフォーマーを添加する方法
で得られた大粒径ペレットの結晶組織を見ると、気孔は
粒内と粒界に均等に存在するか、または結晶粒界に集ま
って存在し、その分、FPガス保持力が低く抑えられてい
る可能性があることが判明した。From this viewpoint, looking at the crystal structure of the large-diameter pellet obtained by the method of adding the pore former described above, the pores are uniformly present in the grains and at the grain boundaries, or are present at the grain boundaries, It turned out that the FP gas holding power may be kept low.
一方、本発明者らはその後の実験により、新たなポア
フォーマーとしてU3O8粉末が使用可能であることを突き
止めた。U3O8をUO2粉末に添加して成形および焼結を行
なうと、U3O8粒子の部分には、UO2粉末との焼結時の収
縮率の違いから気孔を生じ、焼結密度を低下することが
できる。On the other hand, the present inventors have found through subsequent experiments that U 3 O 8 powder can be used as a new pore former. When the U 3 O 8 performs addition to forming and sintering the UO 2 powder, in a portion of the U 3 O 8 particles, resulting pores from differences in shrinkage during sintering of the UO 2 powder, sintered Density can be reduced.
ところが、さらに検討を進めた結果、U3O8粉末の添加
量をある一定範囲にした場合には、従来のポアフォーマ
ーの場合と異なり、気孔が結晶粒子内に多く分散すると
いう新規な現象を発見した。However, as a result of further study, when the amount of U 3 O 8 powder added was within a certain range, a new phenomenon was found that, unlike the conventional pore former, a large number of pores were dispersed in the crystal particles. did.
本発明は、上記知見に基づいてなされたもので、同じ
焼結密度であっても、より高いFPガス保持力が得られる
核燃料ペレットの提供を課題とする。The present invention has been made based on the above findings, and it is an object of the present invention to provide a nuclear fuel pellet capable of obtaining a higher FP gas holding force even at the same sintering density.
「課題を解決するための手段」 以下、本発明に係わる核燃料ペレットを具体的に説明
する。"Means for Solving the Problems" Hereinafter, the nuclear fuel pellets according to the present invention will be specifically described.
本発明の核燃料ペレットは、UO2を主組成物とした原
料粉末を成形し焼結してなるものであって、組織の結晶
粒径が20μｍ以上、望ましくは30〜100μｍ、焼結密度
は94〜97％TDとされ、結晶粒内に分散している気孔が結
晶粒界に存在する気孔よりも多いことを特徴とする。The nuclear fuel pellet of the present invention is obtained by molding and sintering a raw material powder containing UO 2 as a main composition, and has a crystal grain size of 20 μm or more, preferably 30 to 100 μm, and a sintered density of 94 μm. 9797% TD, wherein the number of pores dispersed in the crystal grains is larger than the number of pores existing in the crystal grain boundaries.
結晶粒径が20μｍ未満では、結晶粒内に生じたFPガス
が粒界に到達する距離が短くなるうえ、粒界の分布密度
が高めるために粒界に接触する気孔の割合が増加し、こ
れらの相乗効果により十分なPPガスの保持力が得られな
くなる。また結晶粒径が100μｍより大であると、ペレ
ットの機械的強度が低下するおそれを有する。さらに焼
結密度が94％TD未満あるいは97％TDより大では、いずれ
も製品ペレットの規格を満たすことができない。When the crystal grain size is less than 20 μm, the distance at which the FP gas generated in the crystal grains reaches the grain boundaries is shortened, and the distribution density of the grain boundaries is increased, so that the proportion of pores in contact with the grain boundaries increases. Due to the synergistic effect of the above, sufficient PP gas holding power cannot be obtained. If the crystal grain size is larger than 100 μm, the mechanical strength of the pellet may be reduced. Further, if the sintering density is less than 94% TD or greater than 97% TD, none of them can meet the product pellet specifications.
気孔の平均径は５〜100μｍ、特に10〜50μｍである
ことが望ましく、５μｍ未満では照射中の気孔の消滅に
よりペレットが収縮するという問題を生じ、100μｍよ
り大ではペレット表面の開気孔率が増大するという問題
を生じる。The average diameter of the pores is preferably from 5 to 100 μm, particularly preferably from 10 to 50 μm. If it is less than 5 μm, the pellet shrinks due to disappearance of the pores during irradiation, and if it is more than 100 μm, the open porosity of the pellet surface increases. Problem arises.
上記構成からなる核燃料ペレットでは、結晶粒内に分
散している気孔が結晶粒界に存在する気孔よりも多いた
め、燃焼の進行につれてペレット内で発生するFPガスが
結晶粒内の独立気孔に蓄えられ、しかも粒界を通じてガ
スが放出されることが少ないから、同程度の気孔率を有
する従来のペレットよりもFPガスの放出量を大幅に低減
することができる。In the nuclear fuel pellet having the above configuration, the pores dispersed in the crystal grains are larger than the pores present in the crystal grain boundaries, so that the FP gas generated in the pellet as the combustion progresses is stored in independent pores in the crystal grains. In addition, since gas is hardly released through the grain boundaries, the amount of FP gas released can be significantly reduced as compared with conventional pellets having the same porosity.
次に、このような核燃料ペレットの製造方法の一例を
説明する。Next, an example of a method for producing such a nuclear fuel pellet will be described.
この方法では、比表面積が3m2/g以上、好ましくは５
〜15m2/gの高活性UO2粉末を原料粉末の主組成物として
使用する。3m2/g未満ではレットの結晶粒径を十分大き
くできず、FPガスの保持性が低下する。また、15m2/gよ
り大では粒径が前述した上限値以上になるおそれがあ
る。なお、ここでいう比表面積は、BET法により測定さ
れる値と定義する。In this method, the specific surface area is 3 m 2 / g or more, preferably 5 m 2 / g or more.
活性 15 m 2 / g highly active UO 2 powder is used as the main composition of the raw powder. If it is less than 3 m 2 / g, the crystal grain size of the ret cannot be made sufficiently large, and the retention of FP gas decreases. On the other hand, if it is larger than 15 m 2 / g, the particle size may be higher than the above-mentioned upper limit. Here, the specific surface area is defined as a value measured by the BET method.
このような高活性UO2粉末は、ADU法やAUC法におい
て、沈殿条件のコントロールを行なうことにより容易に
製造できる。その技術についての詳細は、前述した各出
願で本出願人が既に開示している。なお、高活性UO2粉
末は、通常の不活性なUO2粉末に高度の粉砕処理を行な
って比表面積が増大させる方法や、不活性UO2粉末に酸
化還元処理等を行なって高活性化する方法でも得ること
が可能である。Such highly active UO 2 powder can be easily produced by controlling the precipitation conditions in the ADU method or AUC method. Details of the technology have been disclosed by the present applicant in each of the aforementioned applications. In addition, the highly active UO 2 powder is a method of increasing the specific surface area by performing a high degree of pulverization processing on a normal inactive UO 2 powder, or a method of highly activating the inactive UO 2 powder by performing a redox treatment or the like. It can also be obtained by a method.
次に、このような高活性UO2粉末に10〜20wt％のU3O8
粉末を添加する。添加量が20wt％を越えると結晶粒径が
小さくなり、粒界の分布密度が大きくなるため、粒界に
存在する気孔の割合が顕著に大きくなり、FPガス保持力
が相対的に減少する。また、10wt％未満ではペレットの
焼結密度が97％TDを越えてしまう。Next, 10 to 20 wt% of U 3 O 8 is added to such highly active UO 2 powder.
Add powder. If the addition amount exceeds 20 wt%, the crystal grain size becomes smaller and the distribution density of the grain boundaries increases, so that the proportion of pores existing in the grain boundaries becomes remarkably large, and the FP gas holding power relatively decreases. If the content is less than 10 wt%, the sintered density of the pellet exceeds 97% TD.
U3O8粉末の粒径は気孔の平均径と関係があり、望まし
くはその平均粒径が５〜100μｍ程度とされる。５μｍ
未満では前記の気孔平均径の下限値よりも小さくなり、
また100μｍより大では上限値を越える。The particle size of the U 3 O 8 powder is related to the average diameter of the pores, and preferably the average particle size is about 5 to 100 μm. 5 μm
Is less than the lower limit of the pore average diameter,
If it is larger than 100 μm, it exceeds the upper limit.
次いで、この混合粉末をプレス型で成形した後、水素
気流中あるいは加湿した水素気流中で焼結して核燃料ペ
レットを得る。この条件は従来と同様でよい。焼結後に
はU3O8の部分がUO2よりも収縮率が小さいために気孔を
形成し、この気孔が結晶粒内に存在することになる。Next, the mixed powder is formed in a press die, and then sintered in a hydrogen stream or a humidified hydrogen stream to obtain nuclear fuel pellets. This condition may be the same as the conventional one. After sintering, the U 3 O 8 portion has a smaller shrinkage ratio than the UO 2 to form pores, and the pores are present in the crystal grains.
気孔が組織中に均一に分散する理由は未だ明らかでは
ないが、次のような推測が可能である。すなわち、U3O8
粉末とマトリックスとなるUO2粉末とが親和性が高いた
めに、特にU3O8粉末の添加量が20wt％以下の場合には、
焼結時に粒界が気孔を通り越して比較的自由に移動し、
互いに無関係に分散する。しかし、U3O8粉末の添加量が
20wt％より大きくなると、気孔の分布密度が大きくな
り、粒界の移動を阻止する力が無視できなくなって、気
孔と接触した状態で粒界の移動が停まる確率が大きくな
るために、粒界に残る気孔の割合が増加すると考えられ
る。The reason why the pores are uniformly dispersed in the tissue is not yet clear, but the following guess is possible. That is, U 3 O 8
Due to the high affinity between the powder and the UO 2 powder as the matrix, especially when the added amount of U 3 O 8 powder is 20 wt% or less,
During sintering, the grain boundaries move relatively freely past the pores,
Disperse independently of each other. However, the added amount of U 3 O 8 powder
If it exceeds 20 wt%, the distribution density of the pores increases, and the force for preventing the movement of the grain boundaries cannot be ignored, and the probability that the movement of the grain boundaries stops in contact with the pores increases. It is thought that the ratio of the pores remaining in the air increases.
「実施例」 次に、実施例を挙げて本発明の効果を実証する。"Examples" Next, the effects of the present invention will be demonstrated with examples.
UO2F2を水に溶解して作製したUO2F2溶液とアンモニア
水を反応させてADUを生成させ、このADUを濾過および乾
燥ののち焙焼・還元して、比表面積が約10m2/gの高活性
UO2粉末を作製した。The UO 2 F 2 by reacting UO 2 F 2 solution and ammonia water prepared by dissolving in water to produce a ADU, the ADU filtration and drying roasting and reduction to after a specific surface area of about 10 m 2 / g high activity
UO 2 powder was prepared.
この粉末に、U3O8粉末およびシュウ酸アンモニウムを
ポアフォーマーとして添加し、均一に混合して３種の原
料粉末を作製した。U3O8粉末としては粒径が10μｍのも
のを使用した。そしてこれら原料粉末を3t/cm2で成形
し、各圧粉体を水素気流中において1750℃で４時間焼結
した。To this powder, U 3 O 8 powder and ammonium oxalate were added as pore formers and mixed uniformly to prepare three kinds of raw material powders. U 3 O 8 powder having a particle size of 10 μm was used. These raw material powders were molded at 3 t / cm 2 , and each green compact was sintered at 1750 ° C. for 4 hours in a hydrogen stream.
こうして得られた３種の核燃料ペレットを切断し、研
摩およびエッチングの後、光学顕微鏡で組織写真を撮影
した。第１図はU3O8粉末を20wt％添加した核燃料ペレッ
トの組織写真を模写したものに、第２図はU3O8粉末を30
wt％添加した例、第３図はシュウ酸アンモニウムを1wt
％添加した例である。なお、第１図〜第３図において、
斜線を施しているのが気孔であり、その他に気孔のよう
に見えるのはエッチングによるピットである。The three types of nuclear fuel pellets thus obtained were cut, and after polishing and etching, their micrographs were taken with an optical microscope. To that Figure 1 is obtained by replicating the structure photographs of the nuclear fuel pellets added 20 wt% of U 3 O 8 powder, Figure 2 is a U 3 O 8 powder 30
Fig. 3 shows an example of adding 1 wt% of ammonium oxalate.
This is an example in which% is added. 1 to 3,
The hatched portions are pores, and the other portions that look like pores are pits formed by etching.
シュウ酸アンモニウムを添加したペレットでは、結晶
粒径が49μｍであったが、気孔が主に結晶粒界と粒内に
均等に存在している。それに対し、U3O8粉末を20wt％添
加した例では、結晶粒径が48μｍで、大部分の気孔が結
晶粒内に存在している。しかし、U3O8粉末の添加量が30
wt％に増えると、結晶粒径が25μｍに縮小し、粒界にあ
る気孔の割合が顕著に大きくなった。In the pellet to which ammonium oxalate was added, the crystal grain size was 49 μm, but the pores were uniformly present mainly in the crystal grain boundaries and in the grains. On the other hand, in the example in which U 3 O 8 powder was added at 20 wt%, the crystal grain size was 48 μm, and most of the pores were present in the crystal grains. However, the added amount of U 3 O 8 powder is 30
When it increased to wt%, the crystal grain size was reduced to 25 μm, and the proportion of pores at the grain boundaries was significantly increased.
「発明の効果」 以上説明したように、本発明に係わる核燃料ペレット
によれば、結晶粒内に分散している気孔が結晶粒界に存
在する気孔よりも多いため、燃焼の進行につれペレット
内で発生するFPガスが結晶粒内の独立気孔に蓄えられ、
しかも粒界を通じてガスが放出されることが少ないか
ら、同程度の気孔率を有する従来のペレットよりもFPガ
スの保持力を高め、燃焼中のFPガス放出量を低減するこ
とが可能である。[Effects of the Invention] As described above, according to the nuclear fuel pellets of the present invention, the number of pores dispersed in the crystal grains is larger than the number of pores present in the crystal grain boundaries. The generated FP gas is stored in independent pores in the crystal grains,
In addition, since gas is hardly released through the grain boundaries, it is possible to increase the holding power of FP gas and reduce the amount of FP gas released during combustion as compared with conventional pellets having the same porosity.
第１図は本発明の実施例に係わる核燃料ペレットの組織
拡大図、第２図および第３図はそれぞれ比較例の核燃料
ペレットの組織拡大図である。FIG. 1 is an enlarged view of the structure of a nuclear fuel pellet according to an embodiment of the present invention, and FIGS. 2 and 3 are enlarged views of the structure of a nuclear fuel pellet of a comparative example.
Claims (1)
燃料ペレットであって、組織の結晶粒径が20μｍ以上、
焼結密度が94〜97％TDで、かつ結晶粒内に分散している
気孔が結晶粒界に存在する気孔よりも多いことを特徴と
する核燃料ペレット。Claims: 1. A nuclear fuel pellet obtained by molding and sintering a nuclear fuel material powder, wherein the crystal grain size of the structure is 20 μm or more;
A nuclear fuel pellet having a sintering density of 94 to 97% TD and having more pores dispersed in crystal grains than pores present in crystal grain boundaries.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2048240A JP2737350B2 (en) | 1990-02-28 | 1990-02-28 | Nuclear fuel pellets |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2048240A JP2737350B2 (en) | 1990-02-28 | 1990-02-28 | Nuclear fuel pellets |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03249595A JPH03249595A (en) | 1991-11-07 |
| JP2737350B2 true JP2737350B2 (en) | 1998-04-08 |
Family
ID=12797921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2048240A Expired - Lifetime JP2737350B2 (en) | 1990-02-28 | 1990-02-28 | Nuclear fuel pellets |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2737350B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101927276B1 (en) * | 2013-11-26 | 2018-12-10 | 조인트 스탁 컴퍼니 ″아크메-엔지니어링″ | Nuclear fuel pellet having enhanced thermal conductivity, and preparation method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9813696D0 (en) * | 1998-06-26 | 1998-08-26 | British Nuclear Fuels Plc | Fuel pellet |
-
1990
- 1990-02-28 JP JP2048240A patent/JP2737350B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101927276B1 (en) * | 2013-11-26 | 2018-12-10 | 조인트 스탁 컴퍼니 ″아크메-엔지니어링″ | Nuclear fuel pellet having enhanced thermal conductivity, and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03249595A (en) | 1991-11-07 |
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