JP2002022884A - Recovery method for uranium - Google Patents
Recovery method for uraniumInfo
- Publication number
- JP2002022884A JP2002022884A JP2000200611A JP2000200611A JP2002022884A JP 2002022884 A JP2002022884 A JP 2002022884A JP 2000200611 A JP2000200611 A JP 2000200611A JP 2000200611 A JP2000200611 A JP 2000200611A JP 2002022884 A JP2002022884 A JP 2002022884A
- Authority
- JP
- Japan
- Prior art keywords
- nuclear fuel
- spent nuclear
- ncp
- uranium
- nitric acid
- 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.)
- Pending
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
-
- 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
- Extraction Or Liquid Replacement (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、使用済み核燃料の
再処理工程において、当該核燃料からウランを分離回収
する方法に関する。[0001] The present invention relates to a method for separating and recovering uranium from nuclear fuel in a process of reprocessing spent nuclear fuel.
【０００２】[0002]
【従来の技術】使用済み核燃料の再処理工程は、使用済
み核燃料からウラン及びプルトニウムを分離回収し、残
った核分裂生成物（ＦＰ）を除去するための化学的工程
である。現在、工業的に行われている再処理工程は、抽
出剤としてリン酸トリブチルを用い、使用済み核燃料を
溶解した硝酸溶液からウラン及びプルトニウムを抽出す
るピューレックス（ＰＵＲＥＸ）法が唯一の方法であ
る。2. Description of the Related Art A reprocessing step of spent nuclear fuel is a chemical step for separating and recovering uranium and plutonium from spent nuclear fuel and removing remaining fission products (FP). At present, the only reprocessing step that is performed industrially is the PUREX method of extracting uranium and plutonium from a nitric acid solution in which spent nuclear fuel is dissolved using tributyl phosphate as an extractant. .
【０００３】しかしながら、使用済み核燃料は、概ね質
量の約９５％がウラン、約１％がプルトニウム、残りが
ＦＰから構成されているため、上記方法によると、燃料
の大部分を占めるウランを抽出除去するには多量のリン
酸トリブチルが必要である。燃料溶液中のウラン及びプ
ルトニウムは各々６価のウラニルイオン（ＵＯ2 2+）、
４価のプルトニウムイオン（Ｐｕ4+）として存在するの
で、このＵＯ2 2+及びＰｕ4+は逆抽出されて、リン酸ト
リブチルは再利用されるが、これも次第に劣化するの
で、最終的には多量のリン酸トリブチルが廃棄されるこ
ととなる。しかし、リン酸トリブチルはリン化合物であ
るため、高温処理（焼却、熱分解、溶融処理等）を行う
場合、分解時にリン酸が生成し、これがオフガス系に移
行して材料を腐食するという問題があった。[0003] However, the spent nuclear fuel is composed of about 95% by mass of uranium, about 1% by plutonium, and the remainder by FP. Requires a large amount of tributyl phosphate. Uranium and plutonium in the fuel solution are each hexavalent uranyl ion (UO 2 2+ ),
Since it exists as a tetravalent plutonium ion (Pu 4+ ), the UO 2 2+ and Pu 4+ are back-extracted and the tributyl phosphate is reused, but also gradually deteriorates. Means that a large amount of tributyl phosphate is discarded. However, since tributyl phosphate is a phosphorus compound, when high-temperature treatment (incineration, thermal decomposition, melting treatment, etc.) is performed, phosphoric acid is generated at the time of decomposition, which transfers to an off-gas system and corrodes the material. there were.
【０００４】[0004]
【発明が解決しようとする課題】上記問題を解決するた
めに、前記抽出工程の前にウランを粗分離し、抽出工程
以降の負担を軽減するための研究が行われ、ウランを過
飽和濃度にし、固体として沈殿させる晶出法が提案され
ている。しかし、この方法も、ウランをより多く析出さ
せるためには、溶液を冷却することが必要であって、経
費が高くなると共に、ウラン以外の不純物が共沈するた
め、沈殿生成物の処理が厄介であるという欠点があっ
た。In order to solve the above-mentioned problems, researches have been conducted to roughly separate uranium before the extraction step and to reduce the burden after the extraction step. A crystallization method of precipitating as a solid has been proposed. However, this method also requires cooling the solution in order to precipitate more uranium, which increases the cost and also causes co-precipitation of impurities other than uranium. There was a disadvantage that it was.
【０００５】従って、本発明は、簡単な操作で、安価
に、使用済み核燃料中からウランを回収する方法を提供
することを目的とするものである。Accordingly, it is an object of the present invention to provide a method for recovering uranium from spent nuclear fuel at a low cost with a simple operation.
【０００６】[0006]
【課題を解決するための手段】このような実情におい
て、本発明者は種々研究を行った結果、使用済み核燃料
中のＦＰ元素イオンは、硝酸水溶液中で、Ｎ−シクロヘ
キシル−２−ピロリドン（ＮＣＰ）と反応して錯体を形
成するが、その中でウラニルイオンのみが酸性条件下で
水に不溶性のＵＯ2(ＮＯ3)2(ＮＣＰ)2錯体を生成し、他
のＦＰ元素イオン、例えばＹ3+、Ｂａ2+、Ｃｓ+、Ｚｒ
Ｏ2+、Ｐｄ2+、ＲｕＮＯ3+、Ｒｈ3+から得られる錯体は
酸性条件下で水に可溶性であることを見出した。Under such circumstances, the present inventors have conducted various studies and found that FP element ions in spent nuclear fuel can be converted into N-cyclohexyl-2-pyrrolidone (NCP) in a nitric acid aqueous solution. ) To form a complex in which only the uranyl ion forms a UO 2 (NO 3 ) 2 (NCP) 2 complex which is insoluble in water under acidic conditions, and forms other FP element ions such as Y 3+ , Ba2 + , Cs + , Zr
The complex obtained from O 2+ , Pd 2+ , RuNO 3+ , Rh 3+ was found to be soluble in water under acidic conditions.
【０００７】従って、本発明は、使用済み核燃料の再処
理工程において、使用済み核燃料を硝酸水溶液に溶解
し、これにＮＣＰを加えて反応させ、ウラニルイオンを
ＵＯ2(ＮＯ3)2(ＮＣＰ)2の沈殿物として回収することを
特徴とするウランの回収方法を提供するものである。Accordingly, in the present invention, in the reprocessing step of spent nuclear fuel, spent nuclear fuel is dissolved in an aqueous nitric acid solution, NCP is added thereto and reacted, and uranyl ions are converted into UO 2 (NO 3 ) 2 (NCP). The present invention provides a method for recovering uranium, which is characterized in that it is recovered as a precipitate of 2 .
【０００８】[0008]
【発明の実施の形態】本発明方法は、再処理工程に付さ
れる使用済み核燃料について適用することができる。本
発明によれば、まず使用済み核燃料を硝酸水溶液に溶解
させる。硝酸水溶液中には少なくともＦＰ元素イオンと
当量以上の硝酸イオンが存在することが必要であるが、
当該溶液を酸性条件下にするために過剰の硝酸を含むの
が好ましい。DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention can be applied to spent nuclear fuel subjected to a reprocessing step. According to the present invention, first, spent nuclear fuel is dissolved in an aqueous nitric acid solution. In the nitric acid aqueous solution, it is necessary that at least nitric acid ions equivalent to the FP element ions are present,
Preferably, the solution contains an excess of nitric acid to bring the solution under acidic conditions.
【０００９】次いで、この溶液にＮＣＰを加えてよく混
合する。ＮＣＰは無色で粘性の高い液体であり、水と任
意の割合で混合する。ＮＣＰはクリーニング業や製紙業
において広く使用されているほか、オイルやガスのメン
テナンス、感光性樹脂、繊維の染色剤、溶剤等として使
用されているが、錯体形成剤として使用した例はない。Next, NCP is added to this solution and mixed well. NCP is a colorless and highly viscous liquid, and is mixed with water at an arbitrary ratio. NCP is widely used in the cleaning industry and papermaking industry, and is also used as oil and gas maintenance, photosensitive resin, fiber dye, solvent and the like, but there is no example of using it as a complexing agent.
【００１０】使用済み核燃料の硝酸水溶液にＮＣＰを加
え、更に必要によって硝酸を追加して充分に混合し、室
温で放置するとＵＯ2(ＮＯ3)2(ＮＣＰ)2錯体の黄色結晶
が沈殿する。また、硝酸の代りにエーテル、シクロヘキ
サン、クロロホルム等の不溶性溶媒を加えることによっ
ても当該錯体を沈殿させることができる。そして、ウラ
ニルイオン以外のＦＰ元素イオンとの錯体は沈殿しない
ので、使用済み核燃料の硝酸水溶液中からウラニルイオ
ンのみを選択的に分離回収することができる。NCP is added to an aqueous nitric acid solution of spent nuclear fuel, and if necessary, nitric acid is further added and mixed well. When the mixture is left at room temperature, yellow crystals of a UO 2 (NO 3 ) 2 (NCP) 2 complex precipitate. Alternatively, the complex can be precipitated by adding an insoluble solvent such as ether, cyclohexane, or chloroform instead of nitric acid. Further, since complexes with FP element ions other than uranyl ions do not precipitate, only uranyl ions can be selectively separated and recovered from the aqueous nitric acid solution of the used nuclear fuel.
【００１１】分離したＵＯ2(ＮＯ3)2(ＮＣＰ)2の沈殿は
そのまま焼却処理すればよく、これによって得られるウ
ランの酸化物は再利用に供することができる。一方この
ようにして大部分のウラニルイオンを除去した使用済み
核燃料溶液は更に従来の溶媒抽出法、イオン交換法、沈
殿法等に付して再処理を行うことができる。The separated precipitate of UO 2 (NO 3 ) 2 (NCP) 2 may be incinerated as it is, and the resulting uranium oxide can be reused. On the other hand, the spent nuclear fuel solution from which most uranyl ions have been removed in this way can be subjected to a conventional solvent extraction method, ion exchange method, precipitation method or the like to be reprocessed.
【００１２】[0012]
【実施例】次に参考例を挙げて本発明を説明する。Next, the present invention will be described with reference to reference examples.
【００１３】参考例１ ＵＯ2(ＮＯ3)2・６Ｈ2Ｏ １０１．７mg（０．２０２ミ
リモル）を水２mLに溶解し、これにＮＣＰ ０．１２５
mL（０．７４４ミリモル）を加える。これを攪拌すると
暗黄色に変化する。次いで、６５％硝酸２mLを加えて混
合し、１８〜２０℃で放置し、生成した黄色結晶をと
り、冷水、エーテルで洗浄し、乾燥して、ＵＯ2(ＮＯ3)
2(ＮＣＰ)2 １００mgを得た。これはアセトン、ニトロ
メタン、アセトニトリル、ジクロロメタン、フルオロベ
ンゼンに溶解し、水にやや溶解し、シクロヘキサン、エ
ーテル、クロロホルムに不溶である。Reference Example 1 101.7 mg (0.202 mmol) of UO 2 (NO 3 ) 2 .6H 2 O was dissolved in 2 mL of water, and NCP 0.125 was added thereto.
Add mL (0.744 mmol). When this is stirred, it turns dark yellow. Next, 2 mL of 65% nitric acid was added and mixed, and the mixture was allowed to stand at 18 to 20 ° C., and the formed yellow crystals were collected, washed with cold water and ether, dried, and dried to obtain UO 2 (NO 3 ).
100 mg of 2 (NCP) 2 were obtained. It is soluble in acetone, nitromethane, acetonitrile, dichloromethane, fluorobenzene, slightly soluble in water, and insoluble in cyclohexane, ether and chloroform.
【００１４】 元素分析 理論値（％）：Ｃ ３２．９７ Ｈ ４．７１ Ｎ ７．６９ 実測値（％）：Ｃ ３２．８３ Ｈ ４．５６ Ｎ ７．６４ ＩＲ（cm-1）：１６０６〔１６８２〕（νＣ＝Ｏ） ９２７〔９４９，ＵＯ2(ＮＯ3)2(Ｈ2 Ｏ)2〕（νＯ＝Ｕ＝Ｏ）Elemental analysis Theoretical value (%): C 32.97 H 4.71 N 7.69 Actual value (%): C 32.83 H 4.56 N 7.64 IR (cm −1 ): 1606 [ 1682] (νC = O) 927 [949, UO 2 (NO 3 ) 2 (H 2 O) 2 ] (νO = U = O)
【００１５】[0015]
【発明の効果】本発明によれば、簡単な操作で、安価
に、使用済み核燃料から大部分のウラニルイオンを選択
的に除去できるので、その後の再処理操作を大幅に軽減
することができる。According to the present invention, most of the uranyl ions can be selectively removed from spent nuclear fuel with a simple operation and at a low cost, so that the subsequent reprocessing operation can be greatly reduced.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 野上 雅伸 東京都大田区東矢口１−８−１−202 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanobu Nogami 1-8-1-202 Higashiyaguchi, Ota-ku, Tokyo
Claims (1)
使用済み核燃料を硝酸水溶液に溶解し、これにＮ−シク
ロヘキシル−２−ピロリドン（ＮＣＰ）を加えて反応さ
せ、ウラニルイオンをＵＯ2(ＮＯ3)2(ＮＣＰ)2の沈殿物
として回収することを特徴とするウランの回収方法。In the reprocessing step of spent nuclear fuel,
Dissolving the spent nuclear fuel in an aqueous nitric acid solution, adding N-cyclohexyl-2-pyrrolidone (NCP) thereto and reacting the same, and recovering uranyl ions as UO 2 (NO 3 ) 2 (NCP) 2 precipitates. Characteristic uranium recovery method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000200611A JP2002022884A (en) | 2000-07-03 | 2000-07-03 | Recovery method for uranium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000200611A JP2002022884A (en) | 2000-07-03 | 2000-07-03 | Recovery method for uranium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002022884A true JP2002022884A (en) | 2002-01-23 |
Family
ID=18698455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000200611A Pending JP2002022884A (en) | 2000-07-03 | 2000-07-03 | Recovery method for uranium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002022884A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009186399A (en) * | 2008-02-08 | 2009-08-20 | Nippon Tmi Co Ltd | Method for reprocessing spent nuclear fuel |
| JP2015125139A (en) * | 2013-12-27 | 2015-07-06 | 株式会社東芝 | Nuclear fuel substance weighing management method |
-
2000
- 2000-07-03 JP JP2000200611A patent/JP2002022884A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009186399A (en) * | 2008-02-08 | 2009-08-20 | Nippon Tmi Co Ltd | Method for reprocessing spent nuclear fuel |
| JP2015125139A (en) * | 2013-12-27 | 2015-07-06 | 株式会社東芝 | Nuclear fuel substance weighing management method |
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