JPH11248880A - Method for treating spent fuel - Google Patents

Method for treating spent fuel

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Publication number
JPH11248880A
JPH11248880A JP5550798A JP5550798A JPH11248880A JP H11248880 A JPH11248880 A JP H11248880A JP 5550798 A JP5550798 A JP 5550798A JP 5550798 A JP5550798 A JP 5550798A JP H11248880 A JPH11248880 A JP H11248880A
Authority
JP
Japan
Prior art keywords
spent fuel
nitrogen
fuel
atmosphere
partial pressure
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
Application number
JP5550798A
Other languages
Japanese (ja)
Other versions
JP3477357B2 (en
Inventor
Tsunaaki Fujioka
綱昭 藤岡
Tatsuya Iizuka
達哉 飯塚
Yuji Kosaka
裕二 高阪
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEW CLEAR DEV KK
NEW CLEAR DEVELOPMENT KK
Mitsubishi Heavy Industries Ltd
Original Assignee
NEW CLEAR DEV KK
NEW CLEAR DEVELOPMENT KK
Mitsubishi Heavy Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEW CLEAR DEV KK, NEW CLEAR DEVELOPMENT KK, Mitsubishi Heavy Industries Ltd filed Critical NEW CLEAR DEV KK
Priority to JP05550798A priority Critical patent/JP3477357B2/en
Publication of JPH11248880A publication Critical patent/JPH11248880A/en
Application granted granted Critical
Publication of JP3477357B2 publication Critical patent/JP3477357B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies

Landscapes

  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

PROBLEM TO BE SOLVED: To collect uranium in the form of nitride by heating a spent fuel with uranium nitride as a main constituent in a nitrogen atmosphere containing<15> N that is at least a specific nitrogen partial pressure at a specific temperature of a specific amount of time and removing the covering of uranium nitride and pulverizing it and at the same time separating and eliminating a volatile unclear reaction product. SOLUTION: A reaction container 2 is provided with a nitrogen gas supply line 4 for supplying a nitrogen gas containing<15> N to a reaction container 2, an inert gas supply line 5 for supplying an inert gas to the reaction container 2, a gas exhaust line 6, and a heating heater 3, and heats a spent fuel 1 in a nitrogen gas atmosphere. In this configuration, the spent fuel that mainly consists of uranium nitride is heated for approximately 10-30 minutes within the range of 600 deg.C-800 deg.C in a nitrogen gas atmosphere containing<15> N where a nitrogen partial pressure is at least 0.01 atmospheric pressure, and then the spent fuel is heated at least for 30 minutes within the range of 800 deg.C-1,450 deg.C in an atmosphere where nitrogen is set to a partial pressure of 1 atmospheric pressure or less, vacuum, or inert gas atmosphere.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、原子炉で使用され
た燃料の処理方法に関する。[0001] The present invention relates to a method for treating fuel used in a nuclear reactor.

【０００２】[0002]

【従来の技術】原子炉で使用された燃料（以下「使用済
燃料」という）にはウラン、プルトニウム等の有用な燃
料成分が含まれており、これらの燃料成分を原子炉燃料
として再利用するためには、使用済燃料の中から燃料成
分のみを回収する必要がある。2. Description of the Related Art Fuel used in a nuclear reactor (hereinafter referred to as "spent fuel") contains useful fuel components such as uranium and plutonium, and these fuel components are reused as nuclear reactor fuel. Therefore, it is necessary to recover only fuel components from spent fuel.

【０００３】従来、使用済燃料の中から燃料成分を回収
する方法としては種々の方法が提案されており、使用済
燃料に含まれるウランをドライ雰囲気で回収する方法と
しては、使用済燃料を高温に加熱し、その状態で使用済
燃料中のウランに酸素を含む気体と水素を含む気体を交
互に接触させてウランを酸化物の形態で回収する方法が
知られている（Ｎｕｃｌｅａｒ Ｔｅｃｈｎｏｌｏｇｙ
誌 第４１巻 １３７〜１３８頁参照）。Conventionally, various methods have been proposed as a method for recovering fuel components from spent fuel. As a method for recovering uranium contained in spent fuel in a dry atmosphere, spent fuel is heated to a high temperature. A method of recovering uranium in the form of an oxide by alternately contacting a gas containing oxygen and a gas containing hydrogen with uranium in the spent fuel in this state is known (Nuclear Technology).
Journal, Vol. 41, pp. 137-138).

【０００４】[0004]

【発明が解決しようとする課題】ところで、原子炉で使
用される燃料はＵＯ2等のウラン酸化物を主成分とする
酸化物燃料が一般的であるが、これに代わる新燃料とし
てＵＮ等のウラン窒化物を主成分とする窒化物燃料の研
究開発が進められている。このような窒化物燃料は熱伝
導度、内部転換比、融点等に優れていることから、安全
性及び経済性の向上が期待されている。The fuel used in a nuclear reactor is generally an oxide fuel containing uranium oxide such as UO 2 as a main component, but a new fuel such as UN is used as an alternative fuel. Research and development of a nitride fuel containing uranium nitride as a main component has been advanced. Since such a nitride fuel is excellent in thermal conductivity, internal conversion ratio, melting point, and the like, improvement in safety and economy is expected.

【０００５】しかしながら、上述した窒化物燃料の再処
理については現在まで確立されていないのが現状であ
り、酸化物燃料を対象とした従来方法をそのまま適用し
た場合には、使用済燃料中のウラン窒化物が空気による
加熱処理によってウラン酸化物となってしまい、ウラン
窒化物を主成分とする使用済燃料の中からウランを窒化
物の形態で回収できないという問題があった。また、ウ
ラン窒化物を主成分とする使用済燃料を窒素雰囲気の中
で高温に加熱すると、ウラン窒化物がＵＮからＵ2Ｎ3に
変化し、窒素分圧を下げればＵ2Ｎ3がＵＮに戻ることは
化学平衡論的に知られているが、使用済の窒化物燃料を
窒素と反応させたＵ2Ｎ3の粉体とするとともに脱被覆
し、ＵＮとして回収できる最適な処理方法（ＵＮとＵ2
Ｎ3との反応速度、粉体化等の条件を考慮した最適な加
熱温度と加熱時間の関係）が明らかになっていないとい
う課題があった。However, at present, the reprocessing of the nitride fuel described above has not been established so far. If the conventional method for oxide fuel is applied as it is, uranium in the spent fuel is There is a problem in that the nitride becomes uranium oxide by heat treatment with air, and uranium cannot be recovered in the form of nitride from spent fuel containing uranium nitride as a main component. When a spent fuel mainly composed of uranium nitride is heated to a high temperature in a nitrogen atmosphere, the uranium nitride changes from UN to U 2 N 3. If the nitrogen partial pressure is reduced, U 2 N 3 becomes UN 2. Although it is known from chemical equilibrium theory, the most suitable treatment method that can convert spent nitride fuel into U 2 N 3 powder obtained by reacting with nitrogen and decoating and recover as UN ( UN and U 2
There is a problem that the optimal relationship between the heating temperature and the heating time in consideration of the reaction speed with N 3 and the conditions such as pulverization) has not been clarified.

【０００６】本発明は上記の事情に鑑みてなされたもの
で、ウラン窒化物を主成分とする使用済燃料の中からウ
ランを窒化物の形態で回収することのできる使用済燃料
の処理方法を提供することを目的とするものである。[0006] The present invention has been made in view of the above circumstances, and provides a method of treating spent fuel capable of recovering uranium in the form of nitride from spent fuel containing uranium nitride as a main component. It is intended to provide.

【０００７】[0007]

【課題を解決するための手段】かかる目的を達成するた
めに、請求項１の発明は、ウラン窒化物を主成分とする
使用済燃料を窒素分圧０．０１気圧以上の15Ｎを含む窒
素雰囲気の中で６００℃〜８００℃の範囲で１０分〜３
０分程度加熱し、前記ウラン窒化物を雰囲気中の窒素と
反応させてウラン窒化物を脱被覆及び粉体化するととも
に、前記使用済燃料中の揮発性核反応生成物を分離除去
することを特徴とする。請求項２の発明は、ウラン窒化
物を主成分とする使用済燃料を窒素分圧０．０１気圧以
上の15Ｎを含む窒素雰囲気の中で６００℃〜８００℃の
範囲で１０分〜３０分程度加熱した後、窒素を１気圧以
下の分圧にした雰囲気若しくは真空又は不活性ガス雰囲
気の中で前記使用済燃料を８００℃〜１４５０℃の範囲
で３０分以上加熱することを特徴とする。請求項３の発
明は、ウラン窒化物を主成分とする使用済燃料を窒素分
圧０．０１気圧以上の15Ｎを含む窒素雰囲気の中で６０
０℃〜８００℃の範囲で１０分〜３０分程度加熱し、次
いで窒素を１気圧以下の分圧にした雰囲気若しくは真空
又は不活性ガス雰囲気の中で前記使用済燃料を８００℃
〜１４５０℃の範囲で３０分以上加熱した後、前記使用
済燃料に振動を付与して前記使用済燃料を粉体燃料と被
覆材とに分離することを特徴とする。請求項４の発明
は、請求項１又は請求項２記載の使用済燃料の処理方法
において、前記使用済燃料の加熱処理によって前記使用
済燃料中から揮発した核反応生成物を核反応生成物除去
装置により除去することを特徴とする。In order to achieve the above object, a first aspect of the present invention is to provide a method for converting a spent fuel containing uranium nitride as a main component into nitrogen containing 15 N having a partial pressure of nitrogen of 0.01 atm or more. 10 minutes to 3 in the range of 600 ° C to 800 ° C in the atmosphere
Heating for about 0 minutes, reacting the uranium nitride with nitrogen in the atmosphere to decoat and powder the uranium nitride and separate and remove volatile nuclear reaction products in the spent fuel. Features. A second aspect of the present invention is to provide a spent fuel containing uranium nitride as a main component in a nitrogen atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more at a temperature of 600 ° C. to 800 ° C. for 10 minutes to 30 minutes. After the heating, the spent fuel is heated in a range of 800 ° C. to 1450 ° C. for 30 minutes or more in an atmosphere in which nitrogen is at a partial pressure of 1 atm or less, or in a vacuum or an inert gas atmosphere. According to a third aspect of the present invention, a spent fuel containing uranium nitride as a main component is treated in a nitrogen atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more.
The fuel is heated in the range of 0 ° C. to 800 ° C. for about 10 minutes to 30 minutes, and then the spent fuel is heated to 800 ° C. in an atmosphere in which nitrogen is reduced to a partial pressure of 1 atm or less or in a vacuum or inert gas atmosphere.
After heating for 30 minutes or more in the range of １４1450 ° C., the spent fuel is vibrated to separate the spent fuel into a powdered fuel and a cladding material. According to a fourth aspect of the present invention, in the method for treating a spent fuel according to the first or second aspect, a nuclear reaction product volatilized from the spent fuel by the heat treatment of the spent fuel is removed. It is characterized by being removed by a device.

【０００８】[0008]

【発明の実施の形態】以下、本発明の実施形態を図面に
基づいて説明する。本発明に係る使用済燃料の処理方法
を説明する前に、ウラン窒化物（ＵＮ）を窒素雰囲気の
中で加熱処理した場合の実験結果を図３を参照して説明
する。図３はペレット状のウラン窒化物を窒素分圧１気
圧の窒素ガス雰囲気の中で約１５℃／ｍｉｎの速度で加
熱した場合におけるウラン窒化物の重量変化を示す線図
である。Embodiments of the present invention will be described below with reference to the drawings. Before describing the method for treating spent fuel according to the present invention, experimental results when uranium nitride (UN) is heat-treated in a nitrogen atmosphere will be described with reference to FIG. FIG. 3 is a diagram showing a weight change of the uranium nitride when the pellet-shaped uranium nitride is heated at a rate of about 15 ° C./min in a nitrogen gas atmosphere having a nitrogen partial pressure of 1 atm.

【０００９】図３に示す実験結果から明らかなように、
ウラン窒化物を窒素分圧１気圧の窒素ガス雰囲気の中で
加熱し、このときの加熱温度を６００〜８００℃、加熱
時間を１０〜３０分に設定すると、ウラン窒化物が雰囲
気中のＮ2と反応してＵＮからＵ2Ｎ3に変化し、さらに
ウラン窒化物が体積膨張すると共に粉体化することが確
認された。As is clear from the experimental results shown in FIG.
When the uranium nitride is heated in a nitrogen gas atmosphere having a nitrogen partial pressure of 1 atm, and the heating temperature at this time is set to 600 to 800 ° C. and the heating time is set to 10 to 30 minutes, the uranium nitride becomes N 2 in the atmosphere. And changed from UN to U 2 N 3 , further confirming that the uranium nitride expands in volume and powders.

【００１０】また、同図に示す実験結果から明らかなよ
うに、ＵＮからＵ2Ｎ3に変化したウラン窒化物を窒素分
圧１気圧の窒素ガス雰囲気の中で加熱し、このときの加
熱温度を８００〜１４５０℃、加熱時間を３０分以上に
設定すると、Ｕ2Ｎ3が粉体の状態でＵＮになることが確
認された。As is clear from the experimental results shown in FIG. 1, the uranium nitride changed from UN to U 2 N 3 is heated in a nitrogen gas atmosphere at a nitrogen partial pressure of 1 atm. Is set to 800 to 1450 ° C. and the heating time is set to 30 minutes or more, it was confirmed that U 2 N 3 became UN in a powder state.

【００１１】したがって、ウラン窒化物を主成分とする
使用済燃料からウランを回収する場合には、先ず、使用
済燃料を窒素分圧０．０１気圧以上の15Ｎを含む窒素ガ
ス雰囲気の中で加熱する。このとき、加熱温度を６００
〜８００℃、加熱時間を１０〜３０分に設定すると、図
１に示すように、使用済燃料に含まれるウラン窒化物が
窒素ガス雰囲気中のＮ2と反応してＵＮからＵ2Ｎ3に変
化する。また、これと同時に使用済燃料中のウラン窒化
物が体積膨張し、これにより被覆材からのウラン窒化物
の脱被覆と粉体化が促進され、ウラン窒化物の脱被覆と
粉体化が促進されることによりヘリウム、クリプトン、
キセノン、ヨウ素、カーボン等の揮発性核反応生成物が
使用済燃料中から揮発する。Therefore, when recovering uranium from spent fuel containing uranium nitride as a main component, first, the spent fuel is recovered in a nitrogen gas atmosphere containing 15 N with a partial pressure of nitrogen of 0.01 atm or more. Heat. At this time, the heating temperature was set at 600
When the heating time is set to 10 to 30 minutes, the uranium nitride contained in the spent fuel reacts with N 2 in the nitrogen gas atmosphere to convert UN to U 2 N 3 as shown in FIG. Change. At the same time, the uranium nitride in the spent fuel expands in volume, which promotes uranium nitride de-coating and powdering from the cladding material, and promotes uranium nitride de-coating and powdering. Helium, krypton,
Volatile nuclear reaction products such as xenon, iodine and carbon volatilize from spent fuel.

【００１２】次に、使用済燃料を窒素分圧１気圧以下の
雰囲気若しくは真空又は不活性ガス雰囲気の中で３０分
以上加熱する。このとき、加熱温度を８００〜１４５０
℃とすると、図１に示すように、粉体化したウラン窒化
物がＵ2Ｎ3からＵＮに変化するとともに、セシウム、ル
テニウムなどのセミ揮発性核反応生成物が使用済燃料中
から揮発する。Next, the spent fuel is heated for 30 minutes or more in an atmosphere having a nitrogen partial pressure of 1 atm or less, or in a vacuum or inert gas atmosphere. At this time, the heating temperature is set to 800 to 1450.
1C, as shown in FIG. 1, the powdered uranium nitride changes from U 2 N 3 to UN, and semi-volatile nuclear reaction products such as cesium and ruthenium volatilize from the spent fuel. .

【００１３】上述したように、本発明ではウラン窒化物
を主成分とする使用済燃料を窒素分圧０．０１気圧以上
の15Ｎを含む窒素ガス雰囲気の中で６００〜８００℃の
範囲で１０〜３０分程度加熱した後、窒素を１気圧以下
の分圧にした雰囲気若しくは真空又は不活性ガス雰囲気
の中で使用済燃料を８００℃〜１４５０℃の範囲で３０
分間以上加熱することにより、使用済燃料に含まれるウ
ランを窒化物の形態で回収することができる。As described above, in the present invention, a spent fuel containing uranium nitride as a main component is treated at a temperature of 600 to 800 ° C. in a nitrogen gas atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more. After heating for about 30 minutes, the spent fuel is heated at 800 ° C. to 1450 ° C. for 30 minutes in an atmosphere in which nitrogen is at a partial pressure of 1 atm or less, or in a vacuum or inert gas atmosphere.
By heating for more than one minute, uranium contained in the spent fuel can be recovered in the form of nitride.

【００１４】なお、使用済燃料を窒素雰囲気で加熱処理
する場合に窒素分圧を０．０１気圧以上とした理由は、
ＵＮをＮ2と８００℃以下の温度で反応させるためには
窒素分圧が０．０００１気圧以上であれば理論上可能で
あるが、圧力維持制御や処理速度（反応速度）を考慮す
ると、窒素分圧を０．０１気圧以上としたほうが使用済
燃料に含まれるウランを回収し易いためである。また、
図３に示した実験結果によれば、使用済燃料を高温条件
下１気圧の窒素雰囲気でＵ2Ｎ3からＵＮに反応変化して
いる。When the spent fuel is heat-treated in a nitrogen atmosphere, the reason for setting the partial pressure of nitrogen to 0.01 atm or more is as follows.
In order to make UN react with N 2 at a temperature of 800 ° C. or less, it is theoretically possible if the nitrogen partial pressure is 0.0001 atm or more. However, considering the pressure maintenance control and the processing speed (reaction speed), This is because the uranium contained in the spent fuel is more easily recovered when the partial pressure is set to 0.01 atm or more. Also,
According to the experimental results shown in FIG. 3, the spent fuel is changed from U 2 N 3 to UN in a nitrogen atmosphere at 1 atm under a high temperature condition.

【化１】 の反応式でわかるように、Ｎ2すなわち窒素ガスの分圧
をより低くすることにより、反応式の左側から右側へ反
応が進む。従って、窒素を１気圧以下の分圧にした雰囲
気でもＵ2Ｎ3をＵＮに戻すことができ、同様の理由で真
空又は不活性ガス雰囲気でもＵ2Ｎ3をＵＮに戻すことが
できる。Embedded image As can be understood from the reaction formula, the reaction proceeds from the left side to the right side of the reaction formula by lowering the partial pressure of N 2, that is, the nitrogen gas. Therefore, U 2 N 3 can be returned to UN even in an atmosphere in which nitrogen has a partial pressure of 1 atm or less, and for the same reason, U 2 N 3 can be returned to UN even in a vacuum or inert gas atmosphere.

【００１５】次に、上述した本発明に係る使用済燃料の
処理方法を実施するための処理設備の一例を図２に示
す。同図において、１はウラン窒化物を主成分とする使
用済燃料、２は使用済燃料１を窒素ガス雰囲気の中で加
熱するための反応容器、３は反応容器２を加熱するため
のヒータ、４は反応容器２に15Ｎを含む窒素ガスを供給
するための窒素ガス供給ライン、５は反応容器２に不活
性ガスを供給するための不活性ガス供給ラインであり、
これらの窒素ガス供給ライン４及び不活性ガス供給ライ
ン５から反応容器２に供給されたガスは、使用済燃料１
を窒素ガス雰囲気または不活性ガス雰囲気の中で加熱処
理しているときには反応容器２に接続されたガス排出ラ
イン６から核反応生成物除去装置７に送られ、この核反
応生成物除去装置７でガス中の核反応生成物が除去され
る。そして、核反応生成物除去装置７で核反応生成物が
除去されたガスは浄化ガス回収ライン８、開閉弁９、窒
素ガス回収タンク１０および窒素ガス供給ライン４を経
て反応容器２に再供給され、上述した経路を循環するよ
うになっている。Next, FIG. 2 shows an example of processing equipment for carrying out the above-described method for processing spent fuel according to the present invention. In the figure, 1 is a spent fuel containing uranium nitride as a main component, 2 is a reaction vessel for heating the spent fuel 1 in a nitrogen gas atmosphere, 3 is a heater for heating the reaction vessel 2, Reference numeral 4 denotes a nitrogen gas supply line for supplying nitrogen gas containing 15 N to the reaction vessel 2, and 5 denotes an inert gas supply line for supplying an inert gas to the reaction vessel 2.
The gas supplied to the reaction vessel 2 from the nitrogen gas supply line 4 and the inert gas supply line 5 is used for the spent fuel 1
Is subjected to heat treatment in a nitrogen gas atmosphere or an inert gas atmosphere, is sent from a gas discharge line 6 connected to the reaction vessel 2 to a nuclear reaction product removing device 7, and the nuclear reaction product removing device 7 Nuclear reaction products in the gas are removed. Then, the gas from which the nuclear reaction products have been removed by the nuclear reaction product removal device 7 is resupplied to the reaction vessel 2 via the purified gas recovery line 8, the on-off valve 9, the nitrogen gas recovery tank 10, and the nitrogen gas supply line 4. Circulate through the above-mentioned route.

【００１６】また、１１は反応容器２内で加熱処理され
た使用済燃料１に振動を加えて同燃料１を粉体燃料１ａ
と被覆材１ｂとに分離する分離装置であり、この分離装
置１１のメッシュスクリーン１１ａで被覆材１ｂから分
離された粉体燃料１ａは分級装置１２で分級された後、
充填装置１３により被覆管内に充填され、原子炉１５の
燃料１４として用いられる。なお、浄化ガス回収ライン
８には核反応生成物除去装置７から排出される浄化ガス
をオフガスとして排出するためのガス排出ライン１７が
開閉弁１６を介して接続されている。A vibration 11 is applied to the spent fuel 1 which has been heat-treated in the reaction vessel 2 so that the fuel 1 is converted into a powder fuel 1a.
And a cladding material 1b. The powder fuel 1a separated from the cladding material 1b by the mesh screen 11a of the separation device 11 is classified by the classification device 12,
The cladding tube is filled by the filling device 13 and used as fuel 14 of the nuclear reactor 15. In addition, a gas discharge line 17 for discharging the purified gas discharged from the nuclear reaction product removal device 7 as off-gas is connected to the purified gas recovery line 8 via an on-off valve 16.

【００１７】上記のような構成の処理設備を用いれば、
ウラン窒化物を燃料成分とする使用済燃料１からウラン
を窒化物の形態で回収できるとともに、使用済燃料１に
含まれるヘリウム、クリプトン、キセノン、ヨウ素、カ
ーボン、セシウム、ルテニウムなどの核反応生成物をウ
ラン窒化物１から分離除去することができる。また、加
熱処理された使用済燃料１をメッシュスクリーン１１ａ
付きの分離装置１１に投入することにより、使用済燃料
１を粉体燃料１ａと被覆材１ｂとに分離することができ
る。If the processing equipment having the above configuration is used,
Uranium can be recovered in the form of nitride from spent fuel 1 containing uranium nitride as a fuel component, and nuclear reaction products such as helium, krypton, xenon, iodine, carbon, cesium, and ruthenium contained in spent fuel 1 Can be separated and removed from the uranium nitride 1. Further, the spent fuel 1 subjected to the heat treatment is meshed with a mesh screen 11a.
The spent fuel 1 can be separated into the powdered fuel 1a and the cladding material 1b by putting the spent fuel 1 into the separation device 11 provided with the fuel.

【００１８】[0018]

【発明の効果】以上説明したように、本発明によれば、
ウラン窒化物を主成分とする使用済燃料からウランを窒
化物の形態で回収することができる。また、使用済燃料
に含まれるネプツニウム、プルトニウム及びアメリシウ
ムをウランと分離することなく、原子炉燃料としてその
まま再加工し、原子炉で再利用することができる。As described above, according to the present invention,
Uranium can be recovered in the form of nitride from spent fuel containing uranium nitride as a main component. In addition, neptunium, plutonium and americium contained in spent fuel can be reprocessed as reactor fuel without separation from uranium and reused in the reactor.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明に係る使用済燃料の処理方法を説明する
ための図である。FIG. 1 is a diagram for explaining a method for treating spent fuel according to the present invention.

【図２】本発明に係る使用済燃料の処理方法を実施する
ための処理設備の一例を示す図である。FIG. 2 is a diagram showing an example of a processing facility for performing a spent fuel processing method according to the present invention.

【図３】ペレット状のウラン窒化物を窒素分圧１気圧の
窒素ガス雰囲気の中で約１５℃／ｍｉｎの速度で加熱し
た場合におけるウラン窒化物の重量変化を示す線図であ
る。FIG. 3 is a diagram showing a change in weight of uranium nitride when the pellet-shaped uranium nitride is heated at a rate of about 15 ° C./min in a nitrogen gas atmosphere having a nitrogen partial pressure of 1 atm.

【符号の説明】[Explanation of symbols]

１ 使用済燃料 ２ 反応容器 ４ 窒素ガス供給ライン ５ 不活性ガス供給ライン ７ 核反応生成物除去装置 １１ 分離装置 １２ 分級装置 DESCRIPTION OF SYMBOLS 1 Spent fuel 2 Reaction container 4 Nitrogen gas supply line 5 Inert gas supply line 7 Nuclear reaction product removal device 11 Separation device 12 Classification device

───────────────────────────────────────────────────── フロントページの続き (72)発明者 高阪 裕二 茨城県那珂郡東海村舟石川622番地12 ニ ュークリア・デベロップメント株式会社内 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Takasaka 622-12 Funashiishikawa, Tokai-mura, Naka-gun, Ibaraki Pref.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 ウラン窒化物を主成分とする使用済燃料
を窒素分圧０．０１気圧以上の15Ｎを含む窒素雰囲気の
中で６００℃〜８００℃の範囲で１０分〜３０分程度加
熱し、前記ウラン窒化物を雰囲気中の窒素と反応させて
ウラン窒化物を脱被覆及び粉体化するとともに、前記使
用済燃料中の揮発性核反応生成物を分離除去することを
特徴とする使用済燃料の処理方法。1. A spent fuel containing uranium nitride as a main component is heated in a nitrogen atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more at a temperature of 600 to 800 ° C. for about 10 to 30 minutes. And reacting the uranium nitride with nitrogen in the atmosphere to decoat and powder the uranium nitride and to separate and remove volatile nuclear reaction products in the spent fuel. Of spent fuel. 【請求項２】 ウラン窒化物を主成分とする使用済燃料
を窒素分圧０．０１気圧以上の15Ｎを含む窒素雰囲気の
中で６００℃〜８００℃の範囲で１０分〜３０分程度加
熱した後、窒素を１気圧以下の分圧にした雰囲気若しく
は真空又は不活性ガス雰囲気の中で前記使用済燃料を８
００℃〜１４５０℃の範囲で３０分以上加熱することを
特徴とする使用済燃料の処理方法。2. A spent fuel mainly composed of uranium nitride is heated in a nitrogen atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more at a temperature of 600 to 800 ° C. for about 10 to 30 minutes. After that, the spent fuel is placed in an atmosphere in which the partial pressure of nitrogen is reduced to 1 atm or less or in a vacuum or inert gas atmosphere.
A method for treating spent fuel, comprising heating at a temperature in the range of 00C to 1450C for 30 minutes or more. 【請求項３】 ウラン窒化物を主成分とする使用済燃料
を窒素分圧０．０１気圧以上の15Ｎを含む窒素雰囲気の
中で６００℃〜８００℃の範囲で１０分〜３０分程度加
熱し、次いで窒素を１気圧以下の分圧にした雰囲気若し
くは真空又は不活性ガス雰囲気の中で前記使用済燃料を
８００℃〜１４５０℃の範囲で３０分以上加熱した後、
前記使用済燃料に振動を付与して前記使用済燃料を粉体
燃料と被覆材とに分離することを特徴とする使用済燃料
の処理方法。3. A spent fuel containing uranium nitride as a main component is heated in a nitrogen atmosphere containing 15 N at a partial pressure of nitrogen of 0.01 atm or more at a temperature of 600 to 800 ° C. for about 10 to 30 minutes. Then, after heating the spent fuel in a range of 800 ° C. to 1450 ° C. for 30 minutes or more in an atmosphere in which nitrogen is at a partial pressure of 1 atm or less or in a vacuum or inert gas atmosphere,
A method for treating spent fuel, wherein vibration is applied to the spent fuel to separate the spent fuel into a powder fuel and a cladding material. 【請求項４】 請求項１又は請求項２記載の使用済燃料
の処理方法において、前記使用済燃料の加熱処理によっ
て前記使用済燃料中から揮発した核反応生成物を核反応
生成物除去装置により除去することを特徴とする使用済
燃料の処理方法。4. The method for treating spent fuel according to claim 1, wherein a nuclear reaction product volatilized from the spent fuel by the heat treatment of the spent fuel is removed by a nuclear reaction product removing device. A method for treating spent fuel, which comprises removing the fuel.
JP05550798A 1998-03-06 1998-03-06 How to treat spent fuel Expired - Fee Related JP3477357B2 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006017716A (en) * 2004-06-29 2006-01-19 Westinghouse Electric Co Llc Use of nitrogen isotope-enriched actinide fuel in nuclear reactor
KR100759941B1 (en) 2006-06-28 2007-09-18 한국원자력연구원 Separation method and its apparatus of inner particle from coating layer particle of breached triso fuel
KR100969644B1 (en) * 2008-04-15 2010-07-14 한국원자력연구원 A fabrication method of nuclear fuel pellet by using high burnup spent nuclear fuel
KR100969640B1 (en) * 2008-04-15 2010-07-14 한국원자력연구원 A fabrication method of nuclear fuel pellet by using high burnup spent nuclear fuel containing metal impurities
US10378084B2 (en) 2012-08-31 2019-08-13 Hosei University Method for concentrating metal compound by reduction and oxidation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006017716A (en) * 2004-06-29 2006-01-19 Westinghouse Electric Co Llc Use of nitrogen isotope-enriched actinide fuel in nuclear reactor
KR100759941B1 (en) 2006-06-28 2007-09-18 한국원자력연구원 Separation method and its apparatus of inner particle from coating layer particle of breached triso fuel
KR100969644B1 (en) * 2008-04-15 2010-07-14 한국원자력연구원 A fabrication method of nuclear fuel pellet by using high burnup spent nuclear fuel
KR100969640B1 (en) * 2008-04-15 2010-07-14 한국원자력연구원 A fabrication method of nuclear fuel pellet by using high burnup spent nuclear fuel containing metal impurities
US10378084B2 (en) 2012-08-31 2019-08-13 Hosei University Method for concentrating metal compound by reduction and oxidation

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