JPH07198574A - Method of determining heating holding conditions in measurement of oxygen/metal atom ratio by oxidation/ reduction weight method of gadolinia-containing uranium dioxide fuel body and method measuring therefor - Google Patents
Method of determining heating holding conditions in measurement of oxygen/metal atom ratio by oxidation/ reduction weight method of gadolinia-containing uranium dioxide fuel body and method measuring thereforInfo
- Publication number
- JPH07198574A JPH07198574A JP5353796A JP35379693A JPH07198574A JP H07198574 A JPH07198574 A JP H07198574A JP 5353796 A JP5353796 A JP 5353796A JP 35379693 A JP35379693 A JP 35379693A JP H07198574 A JPH07198574 A JP H07198574A
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- Prior art keywords
- gadolinia
- oxidation
- uranium dioxide
- oxygen
- heating
- 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.)
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- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】この発明は、発電用などの原子炉
に使用される可燃性毒物としてガドリニア(ガドリニウ
ム酸化物)を添加した酸化物核燃料の検査方法、特にO
/M比(酸素対金属原子比)を測定する方法に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting an oxide nuclear fuel containing gadolinia (gadolinium oxide) as a combustible poison used in a nuclear reactor for power generation, etc.
/ M ratio (oxygen to metal atom ratio).
【0002】[0002]
【従来の技術】酸化物核燃料ペレットは、核燃料として
の照射挙動を含めた性能を保証するためにはすべての製
造に係わる仕様を満足しなければならない。酸化物核燃
料ペレットのこれらの仕様のうち重要なもののひとつと
して化学量論的組成を有していることを保証する必要が
ある。化学量論的組成を有する酸化物核燃料ペレットで
あることを保証するための検査方法として、すなわち酸
化物核燃料ペレットに過剰酸素の有無そしてその量の定
量化並びに不足(欠乏)酸素の有無そしてその量の定量
化を可能とする測定方法の確立が必須である。UO2 単
体の酸化物核燃料ペレットのO/U比測定の場合、空気
中の800℃の酸化加熱処理により単一相のU3 O8 に
なることが確認されているので、酸化重量法が確立して
いる。混合酸化物核燃料ペレット(UO2 とPuO2 の
固溶体、MOXと言う)のO/M(M=U+Pu)比測
定の場合、ASTM C698に記載されているように
露点0℃の6%水素/ヘリウム混合ガス下で800℃/
6hでO/M比が2.000になることが確認されてい
るので、酸化・還元重量測定法が確立している。一方、
ガドリニア入り酸化物核燃料ペレットのO/M(M=U
+Gd)比の測定の場合、後述するように酸化重量法の
前提条件の不成立の可能性および化学分析の精度の課題
があるが、これらの背景にはガドリニア入り酸化物核燃
料ペレットに関する知見は、UO2 単体及びMOXの場
合と比べ少ないことがある。2. Description of the Related Art Oxide nuclear fuel pellets must satisfy all manufacturing specifications in order to guarantee performance including irradiation behavior as a nuclear fuel. It is necessary to ensure that one of these important specifications for oxide nuclear fuel pellets has a stoichiometric composition. As an inspection method for ensuring that the oxide nuclear fuel pellets have a stoichiometric composition, that is, the presence or absence of excess oxygen in the oxide nuclear fuel pellets and the quantification thereof, and the presence or absence of insufficient (deficient) oxygen and its amount It is essential to establish a measurement method that enables the quantification of In the case of measuring the O / U ratio of the oxide nuclear fuel pellets of UO 2 simple substance, it was confirmed that the single-phase U 3 O 8 was produced by the oxidation heat treatment at 800 ° C. in the air. is doing. When measuring the O / M (M = U + Pu) ratio of mixed oxide nuclear fuel pellets (a solid solution of UO 2 and PuO 2 , referred to as MOX), 6% hydrogen / helium with a dew point of 0 ° C. as described in ASTM C698. 800 ° C / in mixed gas
Since it was confirmed that the O / M ratio reached 2.000 in 6 hours, the oxidation / reduction gravimetric method has been established. on the other hand,
O / M of oxide nuclear fuel pellets containing gadolinia (M = U
In the case of the measurement of the + Gd) ratio, there is a possibility that the preconditions of the oxidative gravimetric method may not be established and the accuracy of the chemical analysis is a problem as described later. It may be less than the case of a single unit and MOX.
【0003】従来のガドリニア(ガドリニウム酸化物)
入りの二酸化ウランの酸素対金属原子比(Oxygen
−to−Metal Ratio:O/M比と呼ぶ)の
測定方法については、ASTM C968−83に記載
されている下記の方法がある。Conventional gadolinia (gadolinium oxide)
Oxygen-to-metal atomic ratio of the filled uranium dioxide (Oxygen
-To-Metal Ratio: called O / M ratio) can be measured by the following method described in ASTM C968-83.
【0004】このASTM C968−83に記載され
ている測定方法は、基本的にはUO2 単体の焼結ペレッ
トの場合と同様に酸化重量法を採用しており、ガドリニ
ア入り二酸化ウランの焼結ペレットを適切な大きさに粉
砕したサンプルを空気中で575℃/2h加熱による予
備酸化し、その後900℃/2h加熱による酸化処理を
もって、U−Gd−O相は(U,Gd)3 O8 (M3 O
8 と呼ぶ、M=U+Gd)になると言う考え方に基ずく
ものである。The measuring method described in ASTM C968-83 basically adopts the oxidization gravimetric method as in the case of the sintered pellet of UO 2 alone, and the sintered pellet of uranium dioxide containing gadolinia is used. A sample crushed to an appropriate size was pre-oxidized by heating at 575 ° C./2 h in air, and then subjected to an oxidation treatment by heating at 900 ° C./2 h to convert the U-Gd-O phase into (U, Gd) 3 O 8 ( M 3 O
It is based on the idea that M = U + Gd), which is called 8 .
【0005】したがって、この測定方法では当該サンプ
ルの酸化処理前後の重量を測定して、当該ガドリニア入
り二酸化ウランの焼結ペレットのO/M比は、下式で与
えられる。Therefore, in this measuring method, the weight of the sample before and after the oxidation treatment is measured, and the O / M ratio of the sintered pellet of uranium dioxide containing gadolinia is given by the following equation.
【0006】 O/M=2.667−{(W2 −W1 )/W2 }(1
7.54538−0.00190E)+0.01GO / M = 2.667 − {(W 2 −W 1 ) / W 2 } (1
7.554538-0.00190E) + 0.01G
【0007】ここで W1 =サンプル初期重量 W2 =酸化処理後のサンプル重量 E=濃縮度(%) G=Gd2 O3 添加量(%)Where W 1 = initial sample weight W 2 = sample weight after oxidation E = concentration (%) G = Gd 2 O 3 addition (%)
【0008】例えば、このASTMC968−83に記
載されている測定方法に準拠した特開昭2−50692
に開示されているガドリニア入り二酸化ウランの焼結ペ
レットのO/M比の測定方法は、加熱酸化を550〜1
000℃としている。For example, Japanese Unexamined Patent Publication (Kokai) No. 2-50692 based on the measuring method described in this ASTM C968-83.
The method for measuring the O / M ratio of sintered pellets of uranium dioxide containing gadolinia disclosed in US Pat.
It is set to 000 ° C.
【0009】[0009]
【発明が解決しようとする課題】しかし、Gd2 O3 添
加量が増加するとMO2 ±x の加熱酸化処理を工夫して
もすべてM3 O8 に到らずMO2 相が残ることが、T.
YatoらのANS Winter Meeting
(1986)において指摘されている。However, if the amount of Gd 2 O 3 added is increased, even if the heat oxidation treatment of MO 2 ± x is devised, all the M 2 O 8 is not reached and the MO 2 phase remains. T.
Yato et al. ANS Winter Meeting
(1986).
【0010】こうして、上記のASTM C968−8
3並びに特開昭2−50692に開示されているガドリ
ニア入り二酸化ウランの焼結ペレットのO/M比の乾式
法である酸化重量法においては、最近の原子炉の運転期
間の長サイクル化に伴いガドリニアの添加量を増加させ
た場合、酸化加熱方法を工夫しても、酸化重量法の前提
となるMO2 から完全にM3 O8 に到らないと言う課題
がある。Thus, the above ASTM C968-8
3 and the oxidative gravimetric method, which is a dry method of the O / M ratio of the sintered pellets of uranium dioxide containing gadolinia, disclosed in Japanese Patent Laid-Open No. 50692/1990, with the recent extension of the operating period of a nuclear reactor, When the amount of gadolinia added is increased, there is a problem that even if the oxidation heating method is devised, MO 2 which is the premise of the oxidation weight method does not completely reach M 3 O 8 .
【0011】また、この事実は本発明者らの加熱酸化処
理後のガドリニア入り二酸化ウランの焼結ペレットのX
線回折実験においても確認された。したがって、このA
STM C968−83に記載されている測定方法は上
記のようなその後に得られた知見により現在では支持さ
れていないと考えられる。This fact is also due to the fact that the X-rays of the sintered pellets of uranium dioxide containing gadolinia after the thermal oxidation treatment of the present inventors.
It was also confirmed in the line diffraction experiment. Therefore, this A
It is considered that the measurement method described in STM C968-83 is not currently supported by the findings obtained as described above.
【0012】一方、上記の乾式法である酸化重量法以外
に、湿式法である従来の化学分析法すなわちガドリニア
入り二酸化ウランの焼結ペレットを硝酸などで溶解し、
化学分析手法によりUとGdの含有率を得て、残部をO
含有率としてO/M比を求めることが出来るが、本湿式
法は乾式法に比較して、化学分析が煩わしいこと、分析
時間が長いこと並びに精度において劣る。On the other hand, in addition to the dry weight method, which is a dry method, a conventional chemical analysis method that is a wet method, that is, sinter pellets of uranium dioxide containing gadolinia are dissolved with nitric acid or the like,
The content ratio of U and Gd is obtained by the chemical analysis method, and the balance is O
Although the O / M ratio can be obtained as the content rate, the present wet method is inferior to the dry method in that the chemical analysis is troublesome, the analysis time is long, and the accuracy is low.
【0013】このようなことから、バラツキの小さく、
精度の良いかつ操作が簡単で短時間にO/M比を測定す
ることが可能な技術の開発が望まれている。この発明は
上記の如き事情に鑑みてなされたものであって、乾式法
である酸化重量法の前提条件の不成立並びに湿式法であ
る化学分析の精度の課題を克服するガドリニア入り二酸
化ウランの焼結ペレットのO/M比の測定方法を提供す
ることを目的とするものである。From the above, the variation is small,
It is desired to develop a technique which is highly accurate, easy to operate, and capable of measuring the O / M ratio in a short time. The present invention has been made in view of the above circumstances, and is a method for sintering gadolinia-containing uranium dioxide that overcomes the problems of the preconditions of the dry weight method, which is a dry method, and the accuracy of chemical analysis, which is a wet method. It is an object to provide a method for measuring the O / M ratio of pellets.
【0014】[0014]
【課題を解決するための手段】この目的に対応して、こ
の発明のガドリニア入り二酸化ウラン燃料体の酸化・還
元重量法による酸素対金属原子比の測定における加熱保
持条件の決定方法は、ガドリニア入り二酸化ウランの燃
料体の酸素対金属原子比が酸化・還元によってほぼ2に
なる加熱保持時間を求める方法であって、酸化・還元熱
処理のための加熱保持温度として600〜1200℃の
温度範囲に対応した化学量論的組成の平衡酸素分圧2〜
3×10-14 から4〜8×10-7atmとなる雰囲気を
形成して既知重量の試料の酸化・還元処理を行い酸化・
還元処理前後の重量差を熱天秤で測定して、加熱保持時
間として1〜24hの時間範囲で加熱保持時間を求める
ことを特徴としている。また、この発明のガドリニア入
り二酸化ウラン燃料体の酸素対金属原子比の測定方法
は、ガドリニア入り二酸化ウランの燃料体の酸素対金属
原子比が2.00となる酸化・還元熱処理の加熱保持条
件でもって酸化・還元熱処理前後の重量変化から当該燃
料体の酸素対金属原子比を測定することを特徴としてい
る。To solve this problem, the method for determining the heating and holding conditions in the measurement of the oxygen-to-metal atomic ratio of the gadolinia-containing uranium dioxide fuel body of the present invention by the oxidation / reduction gravimetric method is the gadolinia-containing method. A method for determining the heating and holding time when the oxygen-to-metal atomic ratio of the fuel body of uranium dioxide becomes approximately 2 by oxidation / reduction, and corresponds to the temperature range of 600 to 1200 ° C as the heating and holding temperature for the oxidation / reduction heat treatment. Equilibrium oxygen partial pressure of stoichiometric composition 2 ~
Oxidation / reduction of a sample of known weight is performed by forming an atmosphere from 3 × 10 -14 to 4-8 × 10 -7 atm.
The difference between the weights before and after the reduction treatment is measured by a thermobalance, and the heating and holding time is obtained in the time range of 1 to 24 hours as the heating and holding time. Further, the method for measuring the oxygen to metal atomic ratio of the gadolinia-containing uranium dioxide fuel body of the present invention is carried out under the heating and holding conditions of the oxidation / reduction heat treatment at which the oxygen to metal atomic ratio of the gadolinia-containing uranium dioxide fuel body becomes 2.00. Therefore, the feature is that the oxygen to metal atomic ratio of the fuel body is measured from the weight change before and after the oxidation / reduction heat treatment.
【0015】[0015]
【作用】ヒータにより加熱用容器内の加熱保持温度を6
00〜1200℃の温度範囲に設定し、加熱保持時間を
1〜24hとする。また、加熱用容器内の雰囲気を化学
量論的組成の平衡酸素分圧2〜3×10-14 から4〜8
×10-7atmとするために、2種類のガスボンベから
2種類の混合ガスを加熱用容器内に供給する。その際、
2種類の混合ガスは、減圧調整弁によって所定の圧力に
して、その後に両者のガス流量調整器によってガス流量
を正確に制御された後にガス混合器により良好に撹拌さ
れ、加熱用容器内に供給される。このように形成された
容器内において、ガドリニア入り二酸化ウランの焼結ペ
レット等のサンプルの酸化・還元処理を行い、酸化・還
元処理前後の重量差を熱天秤で測定する。[Function] The heater keeps the heating and holding temperature in the heating container at 6
The temperature range is set to 00 to 1200 ° C., and the heating and holding time is set to 1 to 24 h. Further, the atmosphere in the heating container is set to equilibrium oxygen partial pressure of stoichiometric composition 2-3 × 10 -14 to 4-8.
In order to obtain × 10 -7 atm, two kinds of mixed gas are supplied into the heating container from two kinds of gas cylinders. that time,
The two kinds of mixed gas are supplied to the heating container after being adjusted to a predetermined pressure by the decompression control valve and then accurately controlled by the gas flow rate regulators of both of them to be well stirred by the gas mixer. To be done. In the container thus formed, a sample such as a sintered pellet of uranium dioxide containing gadolinia is subjected to oxidation / reduction treatment, and the weight difference before and after the oxidation / reduction treatment is measured with a thermobalance.
【0016】[0016]
【実施例】以下、この発明の詳細を一実施例を示す図面
について説明する。まず、この発明の測定方法において
使用する測定装置について説明する。図1において、1
は測定装置である。測定装置1はガス供給装置2、加熱
装置3、秤量装置4、ガス排出装置5を備えている。ガ
ス供給装置2はガスボンベ6,7、減圧調整弁8,1
1、ガス流量調整器12,13、ガス混合器14を有し
て、加熱装置3に接続している。ガスボンベ6,7は所
定の温度下で加熱装置3において所定の酸素分圧を有す
る雰囲気を形成するためのものであって、ガスボンベ6
とガスボンベ7とは異なる種類のガスを収容したもので
ある。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings showing an embodiment. First, a measuring device used in the measuring method of the present invention will be described. In FIG. 1, 1
Is a measuring device. The measuring device 1 includes a gas supply device 2, a heating device 3, a weighing device 4, and a gas discharge device 5. The gas supply device 2 includes gas cylinders 6 and 7, pressure reducing control valves 8 and 1.
1, the gas flow rate regulators 12 and 13, and the gas mixer 14 are provided and are connected to the heating device 3. The gas cylinders 6 and 7 are for forming an atmosphere having a predetermined oxygen partial pressure in the heating device 3 under a predetermined temperature.
The gas cylinder 7 and the gas cylinder 7 contain different kinds of gas.
【0017】加熱装置3は、加熱用容器15と外熱型モ
ータ16とを有している。加熱用容器15は熱天秤17
を収容可能である。秤量装置4としては、この実施例で
は熱天秤17を使用する。ガス排出装置5は出口用サン
プルガス用弁18、出口用酸素計21及びバブラ22を
備えている。The heating device 3 has a heating container 15 and an external heat type motor 16. The heating container 15 is a thermobalance 17.
Can be accommodated. As the weighing device 4, a thermal balance 17 is used in this embodiment. The gas exhausting device 5 includes an outlet sample gas valve 18, an outlet oximeter 21, and a bubbler 22.
【0018】このように構成された測定装置を使用して
ガドリニア入り二酸化ウランの核燃料のO/M比の測定
は次のようにして行なわれる。この実施例では、ガドリ
ニア入り二酸化ウランの核燃料として焼結ペレットを用
いた例についてのものであるが、この他に乾燥処理した
ガドリニア入り二酸化ウランの粉末、または(U,P
u,Gd)O2 ,(Th,Pu,Gd)O2 系の焼結体
または乾燥処理を施した粉末であっても同様の操作によ
って、O/M比の測定を行える。The O / M ratio of the nuclear fuel of uranium dioxide containing gadolinia is measured by using the measuring apparatus having the above-mentioned structure as follows. In this example, sintered pellets were used as a nuclear fuel for gadolinia-containing uranium dioxide, but in addition to this, dried gadolinia-containing uranium dioxide powder, or (U, P
The same operation can be used to measure the O / M ratio even with a u, Gd) O 2 , (Th, Pu, Gd) O 2 based sintered body or a powder subjected to a drying treatment.
【0019】前提として、一般的に酸化物は、その系内
の温度と酸素分圧で決まる酸素ポテンシャル下で平衡状
態となり、その化学量論的組成は定まるとされている。
この前提から、図2にこの発明の化学量論的組成を有す
る10重量%ガドリニア入り二酸化ウランの焼結ペレッ
トの場合の平衡酸素分圧と加熱温度の関係図を示す。こ
の図2の作成に用いたデータは、K.Une and
M.Oguma, J. Nuc1. Mater.,
110(1982)215−222で示されているU
1-y Gdy O2+x においてUの原子価が4価と5価の存
在でバランスすると言うモデルに依っている。この図2
では酸化・還元温度として600〜1200℃の温度範
囲を設定し、これらの加熱保持温度に対応して、U0.86
Gd0.14O2.000 の平衡酸素分圧として2〜3×10
-14 から4〜8×10-7atmとした。As a premise, it is generally said that an oxide is in an equilibrium state under the oxygen potential determined by the temperature and oxygen partial pressure in the system, and the stoichiometric composition thereof is determined.
Based on this assumption, FIG. 2 shows a relationship diagram between the equilibrium oxygen partial pressure and the heating temperature in the case of the sintered pellet of uranium dioxide containing 10 wt% gadolinia having the stoichiometric composition of the present invention. The data used to create this FIG. Une and
M. Oguma, J .; Nuc1. Mater. ,
110 (1982) 215-222, U
It depends on the model that the valence of U in 1-y Gd y O 2 + x is balanced by the existence of tetravalent and pentavalent. This Figure 2
Then, the temperature range of 600 to 1200 ° C is set as the oxidation / reduction temperature, and U 0.86 is set according to these heating and holding temperatures.
2-3x10 as equilibrium oxygen partial pressure of Gd 0.14 O 2.000
-14 to 4-8 × 10 -7 atm.
【0020】図3にこの発明の超化学量論的組成を有す
る10重量%ガドリニア入り二酸化ウランの焼結ペレッ
トの場合の平衡酸素分圧下における還元挙動を示す概念
図を示す。一般的にその系内での酸化物が平衡状態に到
る時間すなわち酸化物の酸化速度・還元速度は高温側で
速いとされている。一般的に酸化物の酸化速度・還元速
度は、同一組成の酸化物においてもその物理的形態すな
わち密度、開気孔率及び実効的な反応に寄与する酸化物
の比表面積に影響される。FIG. 3 is a conceptual diagram showing the reduction behavior under equilibrium oxygen partial pressure in the case of sintered pellets of uranium dioxide containing 10 wt% gadolinia having a superstoichiometric composition of the present invention. It is generally said that the time required for the oxide to reach an equilibrium state in the system, that is, the oxidation rate / reduction rate of the oxide, is high on the high temperature side. In general, the oxidation rate and the reduction rate of an oxide are affected by the physical form of the oxide having the same composition, that is, the density, the open porosity, and the specific surface area of the oxide that contributes to an effective reaction.
【0021】まず、そこで、この発明ではO/M比測定
対象であるガドリニア入り二酸化ウランの焼結ペレツト
の密度等を考慮して、加熱保持時間を1〜24hとなる
ような加熱保持温度を600〜1200℃の温度範囲内
で設定する。なお、サンプルの特性が大きく異なる場合
は、図1に示した熱天秤による加熱保持温度/時間の把
握が必要であるが、通常のサンプル特性の範囲内であれ
ば一旦設定した加熱保持温度/時間条件で酸化・還元熱
処理前後のサンプル秤量で良い。Therefore, in the present invention, in consideration of the density of the sintered pellet of uranium dioxide containing gadolinia, which is the object of O / M ratio measurement, the heating and holding temperature is set to 600 for heating and holding time of 1 to 24 hours. Set within a temperature range of up to 1200 ° C. If the characteristics of the sample are significantly different, it is necessary to grasp the heating / holding temperature / time by the thermobalance shown in Fig. 1, but if it is within the range of normal sample characteristics, the heating / holding temperature / time once set is set. The sample may be weighed before and after the oxidation / reduction heat treatment under the conditions.
【0022】次に、O/M比の測定を行うが、前述の温
度保持条件によって酸化・還元を行なって、熱天秤で秤
量する。すなわち、サンプル10としてガドリニア入り
二酸化ウランの焼結ペレットの例を供した場合について
述べる。先ず、所定の加熱保持温度において所定の酸素
分圧を有する雰囲気を形成するための2種類のガス・ボ
ンベ6,7を備え、これらの所定の圧力を得る為の所定
のガス用の減圧調整弁を介して、更に2種類の混合ガス
を良好に撹拌するためにガス混合器14を通して、加熱
用容器15に供給される。Next, the O / M ratio is measured. Oxidation / reduction is performed under the above-mentioned temperature holding conditions, and the weight is measured by a thermobalance. That is, the case where the example of the sintered pellet of uranium dioxide containing gadolinia is used as the sample 10 will be described. First, there are provided two kinds of gas cylinders 6 and 7 for forming an atmosphere having a predetermined oxygen partial pressure at a predetermined heating and holding temperature, and a decompression control valve for a predetermined gas for obtaining these predetermined pressures. Through the gas mixer 14 to satisfactorily stir the two kinds of mixed gas, and is supplied to the heating container 15.
【0023】ここで、図2に示した所定の温度での所定
の酸素分圧すなわち酸素ポテンシャルを有する雰囲気を
形成する2種類のガスの組み合わせについては、CO2
/CO,CO2 /H2 またはH2 O/H2 などが使用さ
れる。所定の酸素分圧を確保するために所定のガス流量
調整器12,13が設けられており、混合ガスの所定の
酸素分圧を入り口用酸素計23で常時測定し、その測定
値信号は本ガス流量調整器にフィードバックされて、ガ
ス流量を正確に制御できる。[0023] Here, two types of combinations of gases which form an atmosphere having a predetermined oxygen partial pressure, ie, the oxygen potential at a predetermined temperature shown in FIG. 2, CO 2
/ CO, CO 2 / H 2 or H 2 O / H 2 is used. Predetermined gas flow rate regulators 12 and 13 are provided to secure a predetermined oxygen partial pressure, and the predetermined oxygen partial pressure of the mixed gas is constantly measured by the inlet oxygen meter 23, and the measured value signal is It is fed back to the gas flow regulator, and the gas flow can be accurately controlled.
【0024】次に、容器は外熱型のヒータ16により所
定の昇温、保持並びに降温運転が可能である。加熱容器
には熱天秤が設けられており、サンプルの還元・酸化速
度すなわち平衡状態に到達する時間を把握できるように
なっている。一旦、サンプルのO/M比が2.00とな
る測定条件を把握すれば、本熱天秤の必要はないので、
省略できる。図4にこのO/M比測定操作の流れ概念図
を示す。Next, the container can be heated, held, and cooled in a predetermined manner by the externally heated heater 16. The heating container is equipped with a thermobalance so that the rate of reduction / oxidation of the sample, that is, the time to reach the equilibrium state can be grasped. Once the measurement conditions for the sample O / M ratio of 2.00 are known, there is no need for this thermobalance.
It can be omitted. FIG. 4 shows a conceptual flow chart of this O / M ratio measuring operation.
【0025】ガドリニア入り二酸化ウランの焼結ペレッ
トのO/M比の計算は、下式の通りである。 O/M比=2.000−(W2 −W1 )F/(W2 −W
T )The calculation of the O / M ratio of the sintered pellet of uranium dioxide containing gadolinia is as follows. O / M ratio = 2.000- (W 2 -W 1) F / (W 2 -W
T )
【0026】ここで、 W2 :酸化・還元熱処理後のサンプルとボートの重量 W1 :酸化・還元熱処理前のサンプルとボートの重量 F:酸化物の分子量/16 WT :ボートのテア重量である。 最後にガスの排気部には容器内に空気の混入を防止する
ためにバブラ22を設ける。Where W 2 is the weight of the sample and the boat after the oxidation / reduction heat treatment, W 1 is the weight of the sample and the boat before the oxidation / reduction heat treatment, F is the molecular weight of the oxide / 16 W T , and is the tare weight of the boat. is there. Finally, a bubbler 22 is provided at the gas exhaust portion to prevent air from entering the container.
【0027】[0027]
【発明の効果】以上の説明から、明らかな通り、この発
明によれば化学量論的組成を有するガドリニア入り二酸
化ウランの焼結ペレットが望まれるが、本発明によりバ
ラツキの小さいすなわち精度の良いO/M比の測定を行
うことができ、したがってO/M比=2.00であるこ
とを確認したガドリニア入り二酸化ウランの焼結ペレッ
トが核燃料として保証できる。As is apparent from the above description, according to the present invention, a sintered pellet of uranium dioxide containing gadolinia having a stoichiometric composition is desired. / M ratio can be measured, and therefore, the sintered pellet of uranium dioxide containing gadolinia confirmed to have an O / M ratio of 2.00 can be guaranteed as a nuclear fuel.
【図1】O/M比測定装置を示す概念図。FIG. 1 is a conceptual diagram showing an O / M ratio measuring device.
【図2】本発明の化学量論的組成を有する10重量%ガ
ドリニア入り二酸化ウランの焼結ペレットの場合の平衡
酸素分圧と加熱温度の関係図。FIG. 2 is a diagram showing the relationship between equilibrium oxygen partial pressure and heating temperature in the case of a sintered pellet of uranium dioxide containing 10 wt% gadolinia having the stoichiometric composition of the present invention.
【図3】本発明の超化学量論的組成を有する10重量%
ガドリニア入り二酸化ウランの焼結ペレットの場合の平
衡酸素分圧下における還元挙動を示す概念図。FIG. 3 10% by weight with superstoichiometric composition of the invention
The conceptual diagram which shows the reduction | restoration behavior under equilibrium oxygen partial pressure in the case of the sintered pellet of uranium dioxide containing gadolinia.
【図4】本発明のガドリニア入り二酸化ウランのO/M
比測定方法の流れ概念図。FIG. 4 O / M of uranium dioxide containing gadolinia of the present invention
The conceptual flow chart of the ratio measurement method.
1 測定装置 2 ガス供給装置 3 加熱装置 4 秤量装置 5 ガス排出装置 6 ガスボンベ 7 ガスボンベ 8 減圧調整弁 10 サンプル 11 減圧調整弁 12 ガス流量調整器 13 ガス流量調整器 14 ガス混合器 15 加熱用容器 16 外熱型ヒータ 17 熱天秤 18 出口用サンプルガス用弁 21 出口用酸素計 22 バブラ 1 Measuring Device 2 Gas Supply Device 3 Heating Device 4 Weighing Device 5 Gas Discharging Device 6 Gas Cylinder 7 Gas Cylinder 8 Pressure Reduction Adjustment Valve 10 Sample 11 Pressure Reduction Adjustment Valve 12 Gas Flow Regulator 13 Gas Flow Regulator 14 Gas Mixer 15 Heating Container 16 External heat type heater 17 Thermobalance 18 Outlet sample gas valve 21 Outlet oxygen meter 22 Bubbler
Claims (4)
酸素対金属原子比が酸化・還元によってほぼ2になる加
熱保持時間を求める方法であって、酸化・還元熱処理の
ための加熱保持温度として600〜1200℃の温度範
囲に対応した化学量論的組成の平衡酸素分圧2〜3×1
0-14 から4〜8×10-7atmとなる雰囲気を形成し
て既知重量の試料の酸化・還元処理を行い酸化・還元処
理前後の重量差を熱天秤で測定して、加熱保持時間とし
て1〜24hの時間範囲で加熱保持時間を求めることを
特徴とするガドリニア入り二酸化ウラン燃料体の酸化・
還元重量法による酸素対金属原子比の測定における加熱
保持条件の決定方法。1. A method for obtaining a heating and holding time at which the oxygen-to-metal atomic ratio of a fuel body of gadolinia-containing uranium dioxide becomes approximately 2 by oxidation / reduction, and the heating / holding temperature for oxidation / reduction heat treatment is 600 to Equilibrium oxygen partial pressure of stoichiometric composition corresponding to temperature range of 1200 ° C 2-3 × 1
Oxidation / reduction treatment of a sample of known weight is performed by forming an atmosphere of 0-14 to 4-8 × 10 -7 atm, and the weight difference before and after the oxidation / reduction treatment is measured with a thermobalance, and the heating holding time is Oxidation of uranium dioxide fuel containing gadolinia, characterized in that the heating holding time is obtained in the time range of 1 to 24 hours.
A method for determining heating and holding conditions in the measurement of oxygen-to-metal atomic ratio by the reduced weight method.
ンの焼結ペレット、乾燥処理を施したガドリニア入り二
酸化ウランの粉末、または(U,Pu,Gd)O2 、
(Th,Pu,Gd)O2 系の焼結体または乾燥処理を
施した粉末であることを特徴とする請求項1記載のガド
リニア入り二酸化ウラン燃料体の酸化・還元重量法によ
る酸素対金属原子比の測定における加熱保持条件の決定
方法。2. The fuel body is a sintered pellet of uranium dioxide containing gadolinia, a powder of uranium dioxide containing gadolinia subjected to a drying treatment, or (U, Pu, Gd) O 2 ,
The oxygen-to-metal atom by the oxidation / reduction gravimetric method of the gadolinia-containing uranium dioxide fuel body according to claim 1, which is a (Th, Pu, Gd) O 2 -based sintered body or a dried powder. Method of determining heating and holding conditions for measuring ratio.
二酸化ウランの燃料体の酸素対金属原子比が2.00と
なる酸化・還元熱処理の加熱保持条件でもって酸化・還
元熱処理前後の重量変化から当該燃料体の酸素対金属原
子比を測定することを特徴とするガドリニア入り二酸化
ウラン燃料体の酸素対金属原子比の測定方法。3. The weight change before and after the oxidation / reduction heat treatment under the heating and holding conditions of the oxidation / reduction heat treatment in which the oxygen-to-metal atomic ratio of the fuel body of uranium dioxide containing gadolinia obtained by the method of claim 1 becomes 2.00. The method for measuring the oxygen-to-metal atomic ratio of a gadolinia-containing uranium dioxide fuel body is characterized by measuring the oxygen-to-metal atomic ratio of the fuel body.
体はガドリニア入り二酸化ウランの焼結ペレット、乾燥
処理を施したガドリニア入り二酸化ウランの粉末である
ことを特徴とする請求項3記載のガドリニア入り二酸化
ウラン燃料体の酸素対金属原子比の測定方法。4. The gadolinia-containing uranium dioxide powder as the fuel body of gadolinia-containing uranium dioxide is a sintered pellet of gadolinia-containing uranium dioxide or a dried gadolinia-containing uranium dioxide powder. Measuring method of oxygen to metal atomic ratio of fuel body.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5353796A JPH07198574A (en) | 1993-12-28 | 1993-12-28 | Method of determining heating holding conditions in measurement of oxygen/metal atom ratio by oxidation/ reduction weight method of gadolinia-containing uranium dioxide fuel body and method measuring therefor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5353796A JPH07198574A (en) | 1993-12-28 | 1993-12-28 | Method of determining heating holding conditions in measurement of oxygen/metal atom ratio by oxidation/ reduction weight method of gadolinia-containing uranium dioxide fuel body and method measuring therefor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07198574A true JPH07198574A (en) | 1995-08-01 |
Family
ID=18433282
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5353796A Pending JPH07198574A (en) | 1993-12-28 | 1993-12-28 | Method of determining heating holding conditions in measurement of oxygen/metal atom ratio by oxidation/ reduction weight method of gadolinia-containing uranium dioxide fuel body and method measuring therefor |
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JP (1) | JPH07198574A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003065943A (en) * | 2001-08-24 | 2003-03-05 | Fujitsu Ltd | Temperature/humidity adjusting device and method for environmental test |
US7094608B2 (en) * | 2002-04-11 | 2006-08-22 | Korea Atomic Energy Research Institute | Method for measuring lanthanide content dissolved in uranium oxide |
JP2007183108A (en) * | 2006-01-04 | 2007-07-19 | Mitsutoyo Corp | Indenter shaft, and material testing machine |
-
1993
- 1993-12-28 JP JP5353796A patent/JPH07198574A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003065943A (en) * | 2001-08-24 | 2003-03-05 | Fujitsu Ltd | Temperature/humidity adjusting device and method for environmental test |
US7094608B2 (en) * | 2002-04-11 | 2006-08-22 | Korea Atomic Energy Research Institute | Method for measuring lanthanide content dissolved in uranium oxide |
JP2007183108A (en) * | 2006-01-04 | 2007-07-19 | Mitsutoyo Corp | Indenter shaft, and material testing machine |
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