JPS6314789B2 - - Google Patents
Info
- Publication number
- JPS6314789B2 JPS6314789B2 JP55015998A JP1599880A JPS6314789B2 JP S6314789 B2 JPS6314789 B2 JP S6314789B2 JP 55015998 A JP55015998 A JP 55015998A JP 1599880 A JP1599880 A JP 1599880A JP S6314789 B2 JPS6314789 B2 JP S6314789B2
- Authority
- JP
- Japan
- Prior art keywords
- sintering
- powder
- uranium dioxide
- pellets
- uranium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
Description
【発明の詳細な説明】
本発明は核燃料の製造法に係り、とくにエネル
ギー消費の少ない二酸化ウランペレツトの製造法
に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing nuclear fuel, and particularly to a method for producing uranium dioxide pellets with low energy consumption.
二酸化ウランペレツトの製造法は普通濃縮工場
の製品であるUF6（六フツ化ウラン）を加熱して
気体にしてアンモニア水などに注入してADU（重
ウラン酸アンモン）などの化合物として沈殿さ
せ、ろ過洗滌した後、乾燥焙焼してU3O8の形に
し、水素還元してUO2粉末にする。この粉末に結
合剤を加え20t／cm2前後の圧力でプレスして円柱
片状のグリーンペレツトに成型し、これを結合剤
除去のための予備焼結後、水素気流中で1600〜
1800℃に加熱し数時間の本焼結をする。この本焼
結により93〜97％TD（TD：理論密度）の二酸化
ウランペレツトが得られる。この従来の二酸化ウ
ランペレツトの製造法は、充分な理論密度を得る
ため1600〜1800℃の高温で焼結する必要があり、
このため大量の電力を消費する欠点を持つ。 The manufacturing method for uranium dioxide pellets is to heat UF 6 (uranium hexafluoride), a product of an enrichment factory, to gasify it, inject it into ammonia water, etc., precipitate it as a compound such as ADU (ammonium deuterate), and filter it. After washing, it is dried and roasted to form U 3 O 8 , and then hydrogen reduced to UO 2 powder. A binder is added to this powder and pressed at a pressure of around 20t/ cm2 to form a cylindrical green pellet. After preliminary sintering to remove the binder, it is heated to 1600~
Heat to 1800℃ and perform main sintering for several hours. Through this main sintering, uranium dioxide pellets with a TD (TD: theoretical density) of 93 to 97% are obtained. This conventional method for producing uranium dioxide pellets requires sintering at a high temperature of 1,600 to 1,800°C to obtain sufficient theoretical density.
Therefore, it has the disadvantage of consuming a large amount of power.
本発明は上記のような従来技術の欠点を考慮
し、電力（エネルギー）消費の少ない二酸化ウラ
ンペレツトの製造法を得ることを目的とする。 The present invention takes into account the above-mentioned drawbacks of the prior art and aims to provide a method for producing uranium dioxide pellets that consumes less power (energy).
以下に本発明の具体的実施例を説明する。第１
図に本発明における二酸化ウラン（UO2）のペレ
ツト製造法に示す。すなわち、UF6を加熱して気
体にして、次にアンモニア水などに注入して
ADUなどの化合物として沈殿させ、ろ過洗浄し
た後、乾燥焙焼してU3O8の形にする所までは従
来技術と変わらない。ここで、本発明ではU3O8
粉末の一部を取り出し、残りを水素還元しUO2粉
末を作る。一部取り出したU3O8粉末をこのUO2
粉末に加え結合剤を入れて良く混ぜ合わした後、
プレス成型してグリーンペレツトを得る。このグ
リーンペレツトを結合剤除去のため窒素気流中で
予備焼結した後、本焼結を行なう。本焼結は1600
℃以下の温度でまず窒素気流中（本焼結１）、次
に水素気流中（本焼結２）で焼結して二酸化ウラ
ンペレツトの製造法において、焼結機構は従来技
術と異なる。すなわちUO2にU3O8を混ぜると粉
末のＯ／Ｕ比（酸化ウランにおける酸素原子数と
ウラン原子数の比）は２以上になる。この粉末を
加圧成型し本焼結を窒素気流中で行なうとUO2＋
ｘ（ｘ＞０）ペレツトができる。ここでUO2＋ｘ
（ｘ＞０）マトリツクス中に他の酸化物ウランを
析出させないためにはｘは0.25以下の必要があ
り、したがつてUO2粉末に混入するU3O8粉末量
はUO2粉末の20重量％以下でなければならない。
このUO2＋ｘ（ｘ＞０）は格子内に過剰な酸素を
持ち、UO2より格子が不完全なので、マトリツク
ス内での拡散速度がUO2より速い。拡散速度が速
いことは焼結速度が速いことに通じる。UO2＋ｘ
（ｘ＞０）ペレツトは窒素を水素に置換して焼結
を続けることにより容易に還元されUO2ペレツト
が得られる。第２図に本発明における焼結中のペ
レツトＯ／Ｕ比の変化を示す。第３図に本発明に
おける焼結中のペレツト密度変化を従来技術と同
焼結温度の場合を比較して示す。図中、曲線１は
本発明を、曲線２は従来例を示す。 Specific examples of the present invention will be described below. 1st
The figure shows the method for producing pellets of uranium dioxide (UO 2 ) according to the present invention. That is, heat UF 6 to make it a gas, then inject it into aqueous ammonia, etc.
The process is the same as the conventional technology until it is precipitated as a compound such as ADU, filtered and washed, and then dried and roasted to form U 3 O 8 . Here, in the present invention, U 3 O 8
Part of the powder is taken out and the rest is reduced with hydrogen to make UO 2 powder. The U 3 O 8 powder that was partially taken out was converted into this UO 2
After adding the binder to the powder and mixing well,
Press mold to obtain green pellets. After pre-sintering the green pellets in a nitrogen stream to remove the binder, main sintering is performed. Main sintering is 1600
In the method for producing uranium dioxide pellets by first sintering in a nitrogen stream (main sintering 1) and then in a hydrogen stream (main sintering 2) at a temperature below .degree. C., the sintering mechanism is different from the conventional technology. That is, when UO 2 is mixed with U 3 O 8 , the O/U ratio (the ratio of the number of oxygen atoms to the number of uranium atoms in uranium oxide) of the powder becomes 2 or more. When this powder is pressure molded and main sintering is performed in a nitrogen stream, UO 2 +
x (x>0) pellets are formed. Here UO 2 +x
(x>0) In order to prevent other uranium oxides from precipitating in the matrix, x needs to be less than 0.25, so the amount of U 3 O 8 powder mixed in the UO 2 powder is 20% by weight of the UO 2 powder. Must be less than %.
This UO 2 +x (x>0) has excess oxygen in the lattice and has a more incomplete lattice than UO 2 , so its diffusion rate within the matrix is faster than that of UO 2 . A high diffusion rate corresponds to a high sintering rate. UO 2 +x
(x>0) The pellets are easily reduced by replacing nitrogen with hydrogen and continuing sintering to obtain UO 2 pellets. FIG. 2 shows the change in pellet O/U ratio during sintering in the present invention. FIG. 3 shows the change in pellet density during sintering in the present invention in comparison with that in the prior art at the same sintering temperature. In the figure, curve 1 shows the present invention, and curve 2 shows the conventional example.
本発明における製造法は従来技術に比べ焼結速
度が速いので、UO2ペレツトの製造仕様、例えば
密度，結晶粒径が同一なら従来技術より低い焼結
温度もしくは短焼結時間でUO2ペレツトが製造で
きる。従つて製造にかかる電力消費を低減でき
る。さらに従来技術と同じ焼結温度，焼結時間を
この方法に適用すると焼結速度が速いため、結晶
粒径の大きい二酸化ウランペレツトが得られる。
結晶粒径が大きいと、原子炉で照射中発生する気
体状放射性物質KrやXeのようなものの二酸化ウ
ランペレツト外への放出率が小さくなることが知
られており、安全上すぐれたペレツトとなる。 The manufacturing method of the present invention has a faster sintering speed than the conventional technology, so if the manufacturing specifications of the UO 2 pellets, such as density and grain size, are the same, the UO 2 pellets can be produced at a lower sintering temperature or shorter sintering time than the conventional technology. Can be manufactured. Therefore, the power consumption required for manufacturing can be reduced. Furthermore, if the same sintering temperature and sintering time as in the prior art are applied to this method, the sintering speed is high, so that uranium dioxide pellets with large crystal grain sizes can be obtained.
It is known that when the grain size is large, the rate of release of gaseous radioactive substances such as Kr and Xe, which are generated during irradiation in a nuclear reactor, to the outside of the uranium dioxide pellet is reduced, making the pellet superior in terms of safety.
前記実施例において不活性ガスとしての窒素を
アルゴンに、還元ガスとしての水素を一酸化炭素
に変えても同等の効果が期待できる。本発明は従
来技術で使用してきた焼結炉に不活性ガスループ
を加えること、またペレツト製造工程にU3O8粉
末をUO2粉末に混ぜる工程を付け加えるだけで済
むので容易に実現可能な効果がある。 Similar effects can be expected even if the nitrogen used as the inert gas in the above embodiment is replaced with argon and the hydrogen used as the reducing gas is replaced with carbon monoxide. The present invention has effects that can be easily realized because it is only necessary to add an inert gas loop to the sintering furnace used in the prior art, and a step of mixing U 3 O 8 powder with UO 2 powder to the pellet manufacturing process. be.
第１図は本発明における二酸化ウランペレツト
製造工程を示す流れ線図、第２図は本発明におけ
る本焼結中のペレツトＯ／Ｕ比変化を示す特性
図、第３図は本発明における焼結中のペレツト密
度変化を従来例と同焼結温度の場合を比較して示
す特性図である。
Fig. 1 is a flow diagram showing the uranium dioxide pellet production process in the present invention, Fig. 2 is a characteristic diagram showing changes in pellet O/U ratio during main sintering in the present invention, and Fig. 3 is a flow diagram showing the pellet O/U ratio change during sintering in the present invention. FIG. 3 is a characteristic diagram showing a comparison of changes in pellet density between a conventional example and a case at the same sintering temperature.
Claims (1)
る核燃料の製造法において、前記二酸化ウラン粉
末に、二酸化ウラン粉末の20重量％以下の八三酸
化ウラン（U3O8）粉末を混入したのち、その混
合粉末を成型し、ついで前半を不活性雰囲気中、
後半を還元雰囲気中で焼結して成ることを特徴と
する核燃料の製造法。 ２ 不活性雰囲気を実現するために窒素ガスもし
くはアルゴンガス、還元雰囲気を実現するために
水素ガスもしくは一酸化炭素ガスを使用すること
を特徴とする特許請求の範囲第１項記載の核燃料
の製造法。[Claims] 1. In a method for producing nuclear fuel in which uranium dioxide powder is compacted and then sintered, the uranium dioxide powder contains uranium octaoxide (U 3 O 8 ) in an amount of not more than 20% by weight of the uranium dioxide powder. After mixing the powder, the mixed powder is molded, and then the first half is placed in an inert atmosphere.
A method for producing nuclear fuel characterized by sintering the latter half in a reducing atmosphere. 2. The method for producing nuclear fuel according to claim 1, characterized in that nitrogen gas or argon gas is used to create an inert atmosphere, and hydrogen gas or carbon monoxide gas is used to create a reducing atmosphere. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1599880A JPS56114786A (en) | 1980-02-14 | 1980-02-14 | Method of making nuclear fuel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1599880A JPS56114786A (en) | 1980-02-14 | 1980-02-14 | Method of making nuclear fuel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56114786A JPS56114786A (en) | 1981-09-09 |
| JPS6314789B2 true JPS6314789B2 (en) | 1988-04-01 |
Family
ID=11904303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1599880A Granted JPS56114786A (en) | 1980-02-14 | 1980-02-14 | Method of making nuclear fuel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56114786A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63214693A (en) * | 1987-03-04 | 1988-09-07 | 日本ニユクリア・フユエル株式会社 | Manufacture of nuclear fuel sintered body |
| FR2949598B1 (en) * | 2009-09-02 | 2013-03-29 | Commissariat Energie Atomique | PROCESS FOR PREPARING A POROUS NUCLEAR FUEL BASED ON AT LEAST ONE MINOR ACTINIDE |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5354694A (en) * | 1976-10-29 | 1978-05-18 | Toshiba Corp | Nuclear reactor fuel preparing method |
| JPS6042435B2 (en) * | 1978-06-29 | 1985-09-21 | 日本ニユクリア・フユエル株式会社 | Nuclear fuel production method |
-
1980
- 1980-02-14 JP JP1599880A patent/JPS56114786A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56114786A (en) | 1981-09-09 |
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