JPH0636065B2 - Sintering furnace for oxide nuclear fuel - Google Patents
Sintering furnace for oxide nuclear fuelInfo
- Publication number
- JPH0636065B2 JPH0636065B2 JP62248798A JP24879887A JPH0636065B2 JP H0636065 B2 JPH0636065 B2 JP H0636065B2 JP 62248798 A JP62248798 A JP 62248798A JP 24879887 A JP24879887 A JP 24879887A JP H0636065 B2 JPH0636065 B2 JP H0636065B2
- Authority
- JP
- Japan
- Prior art keywords
- zone
- sintering
- gas
- heating
- sintering furnace
- Prior art date
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Classifications
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- 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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- Tunnel Furnaces (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は酸化物核燃料体の焼結炉に係り、詳しくはアン
モニウム・ジウラネイト(AUD)を前駆物質とした二酸化
ラウン(UO2)からFPガスの放出量の少ない大粒径ペレッ
トを低温焼結で製造するのに好適に上記焼結炉に関する
ものである。Description: TECHNICAL FIELD The present invention relates to a sintering furnace for oxide nuclear fuel bodies, and more specifically, it relates to FP gas from a raw dioxide dioxide (UO 2 ) using ammonium diuranate (AUD) as a precursor. The present invention relates to the above-mentioned sintering furnace, which is suitable for producing a large-sized pellet having a small emission amount of a low-temperature sintering.
（従来の技術） この種の焼結に関し、従来、西独 KWU社のNIKUSI法が知
られており、第２図に示すような焼結炉が用いられてい
る。(Prior Art) With regard to this type of sintering, the NIKUSI method of KWU of West Germany is conventionally known, and a sintering furnace as shown in FIG. 2 is used.
即ち、この焼結炉は、炉の両端が入口側酸化雰囲気の加
熱焼結ゾーン(1)、出口側還元雰囲気ゾーン(2)で、中間
にN2ガスをカーテン状に流す領域(3)を介在せしめ、前
記両雰囲気ゾーン(1)(2)を分断する構成となっていて、
酸化雰囲気ゾーン(1)は CO2， CO2／CO， CO2／O2が流
れるように設定され、一方、還元ゾーン(2)は H2O／
H2， H2O／H2／N2が流れるようになっており、温度は共
に1000〜1400℃に設定されている。That is, in this sintering furnace, both ends of the furnace are a heating and sintering zone (1) of an inlet side oxidizing atmosphere, an outlet side reducing atmosphere zone (2), and an area (3) in which a N 2 gas is flowed in a curtain shape in the middle. By interposing, it is configured to divide the both atmosphere zones (1) and (2),
The oxidizing atmosphere zone (1) is set to flow CO 2 , CO 2 / CO, CO 2 / O 2 , while the reducing zone (2) is H 2 O /
H 2 and H 2 O / H 2 / N 2 are designed to flow, and the temperature is set to 1000 to 1400 ° C.
この方法は二酸化ラウン(UO2)ペルットの低温焼結に関
するものであり、通常ペレットの焼結は1600〜1750℃で
あるのに対し、この方法は1000〜1400℃でも可能である
ことが知られている。This method relates to low temperature sintering of laurel dioxide (UO 2 ) pelt, and it is known that this method is also possible at 1000 to 1400 ° C, whereas sintering of pellets is usually 1600 to 1750 ° C. ing.
この方法はAUC(アンモニアウラニルカーボネート)を前
駆物質とした UO2粉末に適用すると雰囲気中に酸素濃度
や、送り速度を変えることにより自在に結晶粒径を変化
させることが可能である。When this method is applied to UO 2 powder using AUC (ammonia uranyl carbonate) as a precursor, it is possible to freely change the crystal grain size by changing the oxygen concentration and the feed rate in the atmosphere.
しかし、一方、この方式はこのままではADU を前駆物質
とする UO2粉末には適用できないこが判っている。However, on the other hand, it has been found that this method cannot be applied to UO 2 powder using ADU as a precursor as it is.
何故ならば酸化雰囲気時の焼結における結晶粒の成長は
粉末中のU4O9の形成の有無にかかっているが、ADU を前
駆物質とする上記 UO2粉末の場合、酸化雰囲気での O/U
の増加は雰囲気中の酸素濃度に敏感であり、U4O9に設定
する方法が難しく、つまるところU3O8になるか、 UO2+X
のままに存在し、目的とする大粒径結晶の製品が得られ
ないためである。とは云え、ADU を前駆物質とした UO2
粉末を用いて低温焼結によりペレットを作ることは斯界
の要求するところであり、そのため、これに適した焼結
方式の検討が望まれている。The reason for this is that the growth of crystal grains during sintering in an oxidizing atmosphere depends on the presence or absence of U 4 O 9 in the powder, but in the case of the above UO 2 powder using ADU as a precursor, / U
The increase of is sensitive to the oxygen concentration in the atmosphere, and it is difficult to set it to U 4 O 9 , eventually becoming U 3 O 8 or UO 2 + X.
This is because it exists as it is, and the intended product with large-sized crystals cannot be obtained. However, UO 2 using ADU as a precursor
It is a demand in the art to make pellets by low-temperature sintering using powder, and therefore a study of a sintering method suitable for this is desired.
（発明が解決しようとする問題点） 本発明者らも上述の如き斯界の要求に対応し、その焼結
手段について種々の検討を試み、成型体を空気中低温で
加熱することにより比較的容易にADU を前駆物質とする
UO2粉末の場合、U4O9を形成できることを確認した。ま
た、この時の加熱時間，加熱温度，雰囲気中の酸素濃度
をコントロールすることにより、成型体中に形成される
U4O9の量を調整でき最終焼結時に結晶粒径の調整が可能
であることが判った。(Problems to be Solved by the Invention) The present inventors have responded to the demands of the field as described above, tried various studies on the sintering means, and relatively easily by heating the molded body in air at a low temperature. To ADU as precursor
In the case of UO 2 powder, it was confirmed that U 4 O 9 can be formed. Further, by controlling the heating time, heating temperature, and oxygen concentration in the atmosphere at this time, it is formed in the molded body.
It was found that the amount of U 4 O 9 can be adjusted and the grain size can be adjusted during final sintering.
即ち本発明は上記結晶粒径の分布を調整することを課題
とし、前記NIKUSI法の焼結に先立ち、低温酸化条件の予
備的加熱を行うことによりADU を前駆物質とした UO2粉
末から大粒径ペレットを含む結晶粒径を調整したペレッ
トを低温焼結で製造することを目的とするものである。That is, the present invention has an object to adjust the distribution of the crystal grain size, and prior to the sintering of the NIKUSI method, preliminary heating under low temperature oxidation conditions is performed to obtain large particles from UO 2 powder using ADU as a precursor. The purpose of the present invention is to produce low-temperature sintering pellets having a controlled crystal grain size including diameter pellets.
（問題点を解決するための手段） 従って、上記目的に適合する本発明の特徴とするところ
は前部が酸化雰囲気の加熱焼結ゾーン，後部が還元ゾー
ンからなり、中間に両ゾーンを分断するN2ガス領域を介
在せしめた前記NIKUSI法焼結炉において、更に前方にN2
ガス又は CO2ガスをパージガスとするガスカーテン部を
介して低温酸化条件の予備加熱ゾーンを付設せしめた点
にある。(Means for Solving the Problems) Therefore, the feature of the present invention which meets the above-mentioned object is that the front part is composed of a heating and sintering zone in an oxidizing atmosphere, the rear part is composed of a reduction zone, and the both zones are separated in the middle. in the NIKUSI method sintering furnace was allowed interposed N 2 gas region, N 2 further forward
The point is that a preheating zone under low-temperature oxidation conditions was attached through a gas curtain part using gas or CO 2 gas as a purge gas.
ここで、上記低温酸化条件の予備加熱ゾーンとは、具体
的にはその後の加熱焼結ゾーン，還元ゾーンが通常1000
〜1400℃の加熱ゾーンであるのに対し、O2/N2有利には
空気流中にて 150〜340 ℃に加熱するゾーンである。Here, the preheating zone under the above-mentioned low temperature oxidation condition specifically means the subsequent heating and sintering zone and the reduction zone are usually 1000
A heating zone of ˜1400 ° C., whereas a zone of heating O 2 / N 2 preferably 150 to 340 ° C. in a stream of air.
なお、酸化雰囲気の加熱焼結ゾーンは CO2，CO2／CO，
CO2／O2が流れるように設定されること、また還元ゾー
ンは H2O／ H2 ， H2O／ H2 ／N2が流れることは従前の
NIKUSI法における焼結炉と同様である。The heating and sintering zone of the oxidizing atmosphere is CO 2 , CO 2 / CO,
The CO 2 / O 2 is set to flow, and the reduction zone is H 2 O / H 2 and H 2 O / H 2 / N 2 flows.
It is similar to the sintering furnace in the NIKUSI method.
（作用） 上記の如き焼結炉を用い、ADU を前駆物質とした UO2粉
末よりペレットを作るときは従来の加熱焼結に先立ち低
温，酸化条件の予備加熱ゾーンを通ることにより酸素濃
度が適切に分散され、酸化雰囲気のO/U の増加を緩やか
として U4O9 に設定することを容易ならしめ、成型体中
のU4O9の存在割合を比較的容易に調整することを可能と
し、これによって焼結体中の結晶粒分布の調整をはか
り、FPガス放出率が小さい大粒径ペレット等を得ること
ができる。(Function) When pellets are made from UO 2 powder using ADU as a precursor using the above-mentioned sintering furnace, the oxygen concentration is appropriate by passing through the preheating zone under low temperature and oxidizing conditions prior to conventional heating and sintering. It makes it easy to set U 4 O 9 as a moderate increase in O / U in the oxidizing atmosphere and makes it possible to adjust the abundance ratio of U 4 O 9 in the molded body relatively easily. Thus, the distribution of crystal grains in the sintered body can be adjusted, and large-sized pellets or the like with a small FP gas release rate can be obtained.
（実施例） 以下、更に本発明の具体的な実施例を添付図面に従って
説明する。(Examples) Specific examples of the present invention will be described below with reference to the accompanying drawings.
第１図は本発明にかかる焼結炉の１例であり、酸化雰囲
気の加熱焼結ゾーン(1)，還元ゾーン(2)を中間にN2ガス
をカーテン状に流す領域(3)を介在せしめて具備してい
ることは前記従来技術における焼結炉と同様であるが、
更に前記酸化雰囲気の加熱焼結ゾーン(1)の前方にN2又
は CO2ガスをパージガスとして流すガスカーテン部(5)
を介して低温，酸化条件の予備加熱ゾーン(4)を設けて
いる。FIG. 1 is an example of a sintering furnace according to the present invention, in which a zone (3) for flowing N 2 gas in a curtain shape is interposed between a heating and sintering zone (1) and a reducing zone (2) in an oxidizing atmosphere. The fact that it has at least the same as the sintering furnace in the above-mentioned prior art,
Further, in front of the heating and sintering zone (1) in the oxidizing atmosphere, a gas curtain part (5) for flowing N 2 or CO 2 gas as a purge gas.
A preheating zone (4) under low temperature and oxidation conditions is provided via the.
ここで前記酸化雰囲気の加熱焼結ゾーンは通常 CO2， C
O2／ CO ， CO2／O2が流れるように、又還元ゾーン(2)
は H2O／ H2 ， H2O／ H2 ／N2が流れるように夫々設定
されており、温度は共に1000〜1400℃に設定されてい
る。Here, the heating and sintering zone of the oxidizing atmosphere is usually CO 2 , C
O 2 / CO, CO 2 / O 2 flow, and reduction zone (2)
Are set so that H 2 O / H 2 and H 2 O / H 2 / N 2 flow respectively, and the temperatures are both set to 1000 to 1400 ° C.
一方、予備加熱ゾーンは O2/N2，有利には空気が流れる
ように設定されており、150 〜 340℃に加熱されてい
る。The preheating zone, on the other hand, is set to allow O 2 / N 2 , preferably air, and is heated to 150-340 ° C.
そこで、今、上記炉を使用し、ペレットを焼結するに際
しては、先ず、予備加熱として150 〜340 ℃の空気中に
て１時間〜６時間加熱することにより成型体内の酸素濃
度を適切に分散させた後、 CO2中、1000〜1400℃，１時
間〜３時間加熱し、更に同温度で水蒸気を含む水素ガス
又はアンモニア分解ガス（ H2 ，N2）中で加熱する。Therefore, when sintering the pellets using the above-mentioned furnace, first, preheating is performed in air at 150 to 340 ° C. for 1 to 6 hours to appropriately disperse the oxygen concentration in the molded body. After that, it is heated in CO 2 at 1000 to 1400 ° C. for 1 to 3 hours, and further heated at the same temperature in hydrogen gas containing ammonia or ammonia decomposition gas (H 2 , N 2 ).
かくして、上記の方法により成型体中のU4O9の存在割合
を調整することにより焼結体中の結晶粒分布を調整す
る。Thus, the distribution of crystal grains in the sintered body is adjusted by adjusting the abundance ratio of U 4 O 9 in the molded body by the above method.
なお、上記焼結炉による焼結に際し、各加熱の間には夫
々パージガス，例えばN2又は CO2ガスを流し前段階のガ
スを除去する。During the sintering in the sintering furnace, a purge gas, for example, N 2 or CO 2 gas is passed between each heating to remove the gas at the previous stage.
次に上記焼結炉を使用し燃料ペレットを焼結した実例を
示す。Next, an example of sintering the fuel pellets using the above sintering furnace will be shown.
（例） ADU は前駆物質とした UO2粉末を原材料とし、 300℃，
空気流量０．１〜0.2m／分の環境下における第１段の予
備加熱酸化過程，300 ℃〜1270℃， CO2流量０．４〜0.
6m／分の酸素分圧調整下における第２段の酸化雰囲気加
熱焼結過程，及びこれに引き続く還元雰囲気での焼結過
程からなる焼結を行い、25〜80μｍの結晶を50％（平均
粒径２０μ）を有する焼結体ペレットを得た。一方、比
較のため通常の還元雰囲気での焼結を行った結果、得ら
れた焼結体の平均結晶粒は7 〜8 μｍで粒径は遥かに小
さいものであった。(Example) ADU is made from UO 2 powder as a precursor,
First stage pre-heating oxidation process in an environment with an air flow rate of 0.1 to 0.2 m / min, 300 ℃ to 1270 ℃, CO 2 flow rate of 0.4 to 0.
Sintering consisting of the second stage heating and sintering process in an oxidizing atmosphere under the control of oxygen partial pressure of 6 m / min and the subsequent sintering process in a reducing atmosphere was performed to obtain a crystal of 25 to 80 μm with 50% (average grain size). A sintered pellet having a diameter of 20 μ) was obtained. On the other hand, as a result of performing sintering in a normal reducing atmosphere for comparison, the average grain size of the obtained sintered body was 7 to 8 μm, and the grain size was much smaller.
（発明の効果） 本発明は以上のように前部が酸化雰囲気の加熱焼結ゾー
ン，後部が還元ゾーンであって中間に両ゾーンを分断す
るN2ガス領域を介設せしめた焼結炉において、加熱焼結
ゾーンの前方にガスカーテン部を介して更に低温酸化条
件の予備加熱ゾーンを設けたものであり、予め低温の酸
化雰囲気で予備的加熱を行うことによりADU と前駆物質
とする UO2粉末の酸化雰囲気時の焼結における結晶粒の
成長に大きく影響するU4O9の形成を良好となし、従来、
その利用が困難視されていたADU を前駆物質とする UO2
粉末の酸化雰囲気での焼結を可能ならしめ、結晶粒を調
整してFPガスの放出率の小さいのみならず、大粒径と小
粒径を適切に分散させたFPガス保持性およびクリープ特
性の良好なペレットをADU を前駆物質とした UO2粉末か
ら低温焼結で容易に製造することが出来る顕著な効果を
有する。(Effects of the Invention) As described above, the present invention is directed to a sintering furnace in which a front part is a heating and sintering zone in an oxidizing atmosphere, a rear part is a reduction zone, and an N 2 gas region that divides both zones is provided in the middle. In addition, a preheating zone under low temperature oxidation conditions is further provided in front of the heating and sintering zone via a gas curtain, and preheating is performed in advance in a low temperature oxidizing atmosphere so that ADU and UO 2 used as a precursor substance. The formation of U 4 O 9 that significantly affects the growth of crystal grains during sintering of powder in an oxidizing atmosphere is considered to be good.
UO 2 using ADU as a precursor, which has been difficult to use
Not only the release rate of FP gas is small by adjusting the crystal grains to enable the sintering of the powder in an oxidizing atmosphere, but also the FP gas retention and creep characteristics in which large and small particles are appropriately dispersed. It has a remarkable effect that good pellets can be easily manufactured from UO 2 powder using ADU as a precursor by low temperature sintering.
しかも、本発明焼結炉は従前のNIKUSI炉に対し前部に予
備加熱ゾーンを付設するために工業的利用に適し、実用
性は頗る大きく、酸化物核燃料体の焼結炉とうして今後
の利用に極めて期待がかけられる。Moreover, the sintering furnace of the present invention is suitable for industrial use because a preheating zone is attached to the front of the conventional NIKUSI furnace, and its practicality is extremely large. There are extremely high expectations for use.
第１図は本発明に係る焼結炉の１例を示す概要図、第２
図は従来の酸化雰囲気低温焼結炉（NIKUSI炉）の構成を
示す概要図である。 (1)……加熱焼結ゾーン， (2)……還元ゾーン， (3)……N2ガス領域， (4)……予備加熱ゾーン， (5)……ガスカーテン，FIG. 1 is a schematic diagram showing an example of a sintering furnace according to the present invention, and FIG.
The figure is a schematic diagram showing the structure of a conventional oxidizing atmosphere low-temperature sintering furnace (NIKUSI furnace). (1) …… Sintering zone, (2) …… Reduction zone, (3) …… N 2 gas region, (4) …… Preheating zone, (5) …… Gas curtain,
Claims (2)
が還元ゾーンであって、中間に両ゾーンを分断するN2ガ
ス領域を介在せしめた酸化物核燃料体の焼結炉におい
て、前記加熱焼結ゾーンの前方にN2ガス又は CO2ガスを
パージガスとするガスカーテン部を介して低温酸化条件
の予備加熱ゾーンを付設せしめたことを特徴とする酸化
物核燃料体の焼結炉。1. A sintering furnace for an oxide nuclear fuel body, wherein the front part is a heating and sintering zone in an oxidizing atmosphere, the rear part is a reduction zone, and an N 2 gas region that divides both zones is interposed in the middle. A sintering furnace for an oxide nuclear fuel body, characterized in that a preheating zone under low-temperature oxidation conditions is additionally provided in front of the heating and sintering zone via a gas curtain part using N 2 gas or CO 2 gas as a purge gas.
〜1400℃の加熱ゾーンであり、還元ゾーンが水素ガスを
主ガスとする同じく1000〜1400℃のゾーンであると共
に、予備加熱ゾーンはO2，N2又は空気流中にて150 〜34
0 ℃に加熱する加熱ゾーンである特許請求の範囲第１項
記載の酸化物核燃料体の焼結炉。2. A heating / sintering zone whose main gas is CO 2 1000
It is a heating zone of ~ 1400 ° C, a reduction zone is also a zone of 1000 ~ 1400 ° C with hydrogen gas as a main gas, and a preheating zone is 150 ~ 34 in O 2 , N 2 or air flow.
The sintering furnace for an oxide nuclear fuel body according to claim 1, which is a heating zone for heating to 0 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62248798A JPH0636065B2 (en) | 1987-10-01 | 1987-10-01 | Sintering furnace for oxide nuclear fuel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62248798A JPH0636065B2 (en) | 1987-10-01 | 1987-10-01 | Sintering furnace for oxide nuclear fuel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6491094A JPS6491094A (en) | 1989-04-10 |
| JPH0636065B2 true JPH0636065B2 (en) | 1994-05-11 |
Family
ID=17183555
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62248798A Expired - Lifetime JPH0636065B2 (en) | 1987-10-01 | 1987-10-01 | Sintering furnace for oxide nuclear fuel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0636065B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0449015U (en) * | 1990-06-23 | 1992-04-24 | ||
| JPH0449016U (en) * | 1990-06-23 | 1992-04-24 | ||
| JP2696268B2 (en) * | 1990-10-29 | 1998-01-14 | 原子燃料工業株式会社 | Method for producing nuclear fuel sintered body and its sintering furnace |
| KR101165452B1 (en) | 2010-10-20 | 2012-07-12 | 한국수력원자력 주식회사 | Method of controlling the grain boundary and around the grain boundary solubility of doped elements and the manufacturing process of large grain nuclear fuel pellets by using those method |
| FR2997786B1 (en) * | 2012-11-08 | 2018-12-07 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | NUCLEAR FUEL OXIDE REGULATOR OF CORROSIVE FUEL PRODUCTS ADDITIVE BY AT LEAST ONE OXYDO-REDUCER SYSTEM |
| US9646729B2 (en) * | 2013-01-18 | 2017-05-09 | Westinghouse Electric Company Llc | Laser sintering systems and methods for remote manufacture of high density pellets containing highly radioactive elements |
-
1987
- 1987-10-01 JP JP62248798A patent/JPH0636065B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6491094A (en) | 1989-04-10 |
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