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Journal Articles

Basic study on radiation degradation of potassium nickel ferrocyanide

Arai, Yoichi; Watanabe, So; Takahatake, Yoko; Nakamura, Masahiro; Nakajima, Yasuo

Proceedings of 2014 Nuclear Plant Chemistry Conference (NPC 2014) (USB Flash Drive), 8 Pages, 2014/10

no abstracts in English

Journal Articles

Dissolution behavior of (U,Zr)O$$_{2}$$-based simulated fuel debris in nitric acid

Ikeuchi, Hirotomo; Ishihara, Miho; Yano, Kimihiko; Kaji, Naoya; Nakajima, Yasuo; Washiya, Tadahiro

Journal of Nuclear Science and Technology, 51(7-8), p.996 - 1005, 2014/07

 Times Cited Count:8 Percentile:53.05(Nuclear Science & Technology)

Journal Articles

Co-processing of uranium and plutonium for sodium-cooled fast reactor fuel reprocessing by acid split method for plutonium partitioning without reductant

Nakahara, Masaumi; Koma, Yoshikazu; Nakajima, Yasuo

Journal of Nuclear Science and Technology, 50(11), p.1062 - 1070, 2013/11

 Times Cited Count:4 Percentile:32.11(Nuclear Science & Technology)

The acid split method for Pu partitioning without reductant was investigated for improving nuclear proliferation resistance, safety, and cost. A practical acid split flow sheet was configured using a extraction calculation code, and countercurrent experiment was carried out based on their calculation results. 0.15 mol/dm$$^{3}$$ HNO$$_{3}$$ was supplied at 21$$^{circ}$$C for the Pu stripping. The Pu content of the U/Pu product increased to 2.28 times larger than that of the feed solution. In addition, the Pu leakage to the U product was 0.47%. The experimental results indicate that the proposed flow sheet is effective for fast reactor fuel reprocessing.

Journal Articles

Plutonium partitioning in uranium and plutonium co-recovery system for fast reactor fuel recycling with enhanced nuclear proliferation resistance

Nakahara, Masaumi; Koma, Yoshikazu; Nakajima, Yasuo

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.539 - 542, 2013/09

In order to develop a fast reactor fuel reprocessing, countercurrent extraction experiments for Pu reduction partitioning method with hydroxylamine nitrate and acid split method without Pu reductant were carried out. In the Pu reduction method, a part of U was co-recovered with Pu because the U scrubbing part can be deleted in the Pu partitioning section. On the other hand, acid split method experimental results indicate that almost all Pu was recovered with U by supplying diluted HNO$$_{3}$$ solution in the Pu partitioning section. This study shows that not only Pu reduction partitioning but also acid split methods are effective for fast reactor fuel reprocessing.

Journal Articles

Corrosion behavior of a titanium alloy in hot nitric acid condensate

Takeuchi, Masayuki; Sano, Yuichi; Nakajima, Yasuo; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

Journal of Energy and Power Engineering, 7(6), p.1090 - 1096, 2013/06

The corrosion behavior of a titanium-5% tantalum alloy (Ti-5Ta) in hot nitric acid condensate was investigated to understand aging behavior of reprocessing equipments. On the basis of long-term immersion tests, it was determined that the corrosion of Ti-5Ta in nitric acid condensate is accelerated with an increase in the concentration. The corrosion rate was nearly constant during the immersion test and the coupons suffered from uniform corrosion. In addition, it is important to note that the nitric acid concentration in the condensate increased on addition of metal salts to the heated nitric acid solution. The larger valence of metal ions was contributed to the increase in the concentration of nitric acid condensate. Consequently, the metal salt in the heated nitric acid solution accelerates the corrosion of Ti-5Ta in the condensate. Therefore, the nitric acid condensate condition should be carefully considered for the corrosion environment of titanium and its alloys.

Journal Articles

Washing of uranyl nitrate hexahydrate crystals with nitric acid aqueous solution to improve crystal quality

Nakahara, Masaumi; Nakajima, Yasuo; Koizumi, Tsutomu

Industrial & Engineering Chemistry Research, 51(46), p.15170 - 15175, 2012/11

 Times Cited Count:2 Percentile:11.03(Engineering, Chemical)

In the crystal washing experiment using the uranyl nitrate solution containing Ce, the Ce in the mother liquor was attached to the surface of the uranyl nitrate hexahydrate crystals and tend to be removed by the washing operation with low HNO$$_{3}$$ concentration washing solution. In the crystallization experiments using the dissolver solution of irradiated fast reactor core fuel, the decontamination factors of liquid impurities were improved by crystal washing. On the other hand, the decontamination factors of solid impurities decreased with several washings because uranyl nitrate hexahydrate is more soluble than the solid impurities in an HNO$$_{3}$$ solution.

Journal Articles

Extraction behavior of fission products with tri-${it n}$-butyl phosphate by countercurrent multistage extraction in a uranium, plutonium, and neptunium co-recovery system

Nakahara, Masaumi; Nakajima, Yasuo; Koizumi, Tsutomu

Industrial & Engineering Chemistry Research, 51(40), p.13245 - 13250, 2012/10

 Times Cited Count:7 Percentile:26.82(Engineering, Chemical)

To study the extraction behavior of fission products, the countercurrent multistage experiments were carried out with centrifugal contactors in the U, Pu, and Np co-recovery system. Neptunium was co-recovered with U and Pu using tri-${it n}$-butyl phosphate. The experimental results show that Zr was removed with a low HNO$$_{3}$$ concentration scrubbing solution and Tc was decontaminated using a high HNO$$_{3}$$ concentration solution. Other fission products were effectively decontaminated in the system.

Journal Articles

Corrosion study of titanium-5% tantalum alloy in hot nitric acid condensate

Takeuchi, Masayuki; Sano, Yuichi; Nakajima, Yasuo; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 6 Pages, 2012/07

A long-term corrosion tendency and metal salt effect in heating nitric acid solution on corrosion behavior of titanium-5% tantalum alloy (Ti-5Ta) in hot nitric acid condensate condition were mainly researched to discuss the aging behavior of reprocessing equipments such as evaporators made of titanium or its alloy. The hot pure nitric acid solution with continuous renewing such as the nitric acid condensate condition is severe corrosion environment for their materials because of the corrosion inhibition effect from titanium ions as corrosion products or oxidizing ions in nitric acid solution. From the results of the long-term corrosion test for total 11,000 hrs, the corrosion of Ti-5Ta in the nitric acid condensate was accelerated with increase of the nitric acid concentration in the condensate. The corrosion rate was nearly constant during the immersion time and the test coupons suffered a uniform corrosion. Thus, from the viewpoints of nitric acid corrosion, the life-time of the reprocessing equipments made of titanium or its alloy will be roughly estimated based on the results of average corrosion rate in operation. It was also found that the kind and concentration of metal salt in the heating nitric acid solution gave a remarkable effect on the concentration of nitric acid vapor and the corrosion of Ti-5Ta in the hot nitric acid condensate. Most of the evaporators for reprocessing plants include metal ions in the heating nitric acid solution, so the metal salt effect is one of the corrosion factors to control the corrosion behavior of titanium alloy in condensate. The nitric acid concentration in the condensate increases by adding the metal salts in the heating nitric acid solution, in addition, the larger valence of metal ions was contributed to the increase of nitric acid concentration in the condensate. Consequently, the metal salts effect in the heating nitric acid solution accelerates the corrosion of Ti-5Ta in the nitric acid condensate.

Journal Articles

MA recovery experiments from genuine HLLW by extraction chromatography

Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Koma, Yoshikazu; Nakajima, Yasuo

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12

Extraction chromatography experiments with two promising flow-sheets on genuine high level liquid wastes were carried out for demonstrating the feasibility of the method. One flow-sheet consists of CMPO/SiO$$_{2}$$-P and HDEHP/SiO$$_{2}$$-P adsorbent columns, and the other consists of TODGA/ SiO$$_{2}$$-P and isoHex-BTP/SiO$$_{2}$$-P adsorbent columns. Although recovery yields of MA and decontamination factors of FPs obtained by those experiments were lower than the required values, the second flow-sheet is expected to achieve the required performance providing that some minor improvements on the flow-sheet or the adsorbents are applied.

Journal Articles

Study on cleaing solvents using activated alumina in PUREX process

Arai, Yoichi; Ogino, Hideki; Takeuchi, Masayuki; Kase, Takeshi; Nakajima, Yasuo

Proceedings in Radiochemistry, 1(1), p.71 - 74, 2011/09

Solvent cleanup method using activated alumina was discussed in this study. This method was one of candidate to remove TBP/$$n$$-dodecane degradation products. The degradation sample of 30% TBP/$$n$$-dodecane was prepared by irradiation (1.6 MGy) using $$^{60}$$Co $$gamma$$-source. The absorbed dose for sample was almost 1.6 MGy. The degradation products were qualitatively analyzed by gas chromatography-mass spectrometer (GC-MS). After the irradiation, solvent cleanup was performed by activated alumina and the cleanup using alumina was examined by phase separation test with 3M HNO$$_{3}$$. As the result, it was found that hexane and long-chain alcohols were mainly generated as the n-dodecane degradation products by irradiation, and almost 70% of the TBP/$$n$$-dodecane degradation products were removed and the phase separation performance were improved by the cleanup using activated alumina.

Journal Articles

Controls of chromium and third element contents in nickel-base alloys for corrosion resistant alloys in hot HNO$$_3$$-HF mixtures

Takeuchi, Masayuki; Nakajima, Yasuo; Hoshino, Kuniyoshi*; Kawamura, Fumio*

Journal of Alloys and Compounds, 506(1), p.194 - 200, 2010/09

 Times Cited Count:10 Percentile:48.94(Chemistry, Physical)

Journal Articles

Maintenance activities in chemical processing facility, 1; Renewal of driving unit of negative pressure control valves

Kobayashi, Yuki; Takahashi, Tetsuro; Shinozaki, Tadahiro; Ogasawara, Koji; Koizumi, Kenji; Nakajima, Yasuo

Nihon Hozen Gakkai Dai-7-Kai Gakujutsu Koenkai Yoshishu, p.161 - 166, 2010/07

The negative pressure control valve is reliable apparatus which has been used in many nuclear facilities. In recent years, there are some troubles on those valves in CPF (Chemical Reprocessing Facility) by the aged deterioration because the valves were kept using for more than 25 years after facility had operated. Therefore, we have been carrying out renewal of driving units of the valves to assure performance of negative pressure control function and to keep stability of operation of the facility. In this presentation, we report knowledge provided through the renewal work, such as the renewal procedure, the deterioration situation of components and the cause of troubles.

Journal Articles

Extraction and stripping tests of engineering-scale centrifugal contactors cascade system for spent nuclear fuel reprocessing

Takeuchi, Masayuki; Ogino, Hideki; Nakabayashi, Hiroki; Arai, Yoichi; Washiya, Tadahiro; Kase, Takeshi; Nakajima, Yasuo

Journal of Nuclear Science and Technology, 46(3), p.217 - 225, 2009/03

 Times Cited Count:11 Percentile:59.56(Nuclear Science & Technology)

Journal Articles

Waste management implications of advanced fuel cycle systems using Fast Reactors (FR)

Funasaka, Hideyuki; Koma, Yoshikazu; Sato, Koji; Nakajima, Yasuo; Shiotani, Hiroki; Kato, Atsushi; Higuchi, Tatsuya; Namba, Takashi

Proceedings of International Waste Management Symposium 2006 (WM '06) (CD-ROM), 13 Pages, 2006/02

Feasibility Study on commercialized FR cycle systems has been carried out by a Japanese joint team with the participation of all parties concerned in Japan since 1999. The result of the PhaseII (JFY 2001-2005) will work out until March 2006, and then the prospective of the promising concepts and the key issues for the commercialization will be summarized. In this paper, the candidate reprocessing systems studied in the Phase II are reviewed from the view point of compatibility with the reduction of environmental burden.

Journal Articles

Present Status and Prospects in the FR Fuel Cycle System in Japan

Nakajima, Yasuo; Funasaka, Hideyuki; ; Nagaoki, Yoshihiro

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 0 Pages, 2003/00

Journal Articles

None

; Pouchon, M. A.; ;

Saikuru Kiko Giho, (15), p.47 - 57, 2002/06

None

Journal Articles

Development of sphere-pac nuclear fuel behavior analysis code

; ; Pouchon, M. A.

Proceedings of Actinides 2001, 0 Pages, 2001/11

In the feasibility study of a FBRcycle system,alternative nuclear fuel designs are considered. The "sphere-pac" fuel design is one option, which consists of a spherical particle bed vibro-packed into the fuel pin cladding. The advantages of this concept would be a less-powder in fuel production and a lower mechanical interaction between fuel and cladding. JNC has developed a new fuel irradiation behavi

Journal Articles

Sphere bed thermal conductivity

Pouchon, M. A.; ;

Beikoku Seramikku Gakkai Dai-103-Kai Nenji Taikai, 0 Pages, 2000/00

None

JAEA Reports

None

Endo, Hideo; ; ; ; ; ; Tobita, Noriyuki

PNC TN8410 93-280, 235 Pages, 1993/10

PNC-TN8410-93-280.pdf:4.02MB

None

Journal Articles

None

; ; ; Abe, Tomiyuki; Matsumoto, Mitsuo

Donen Giho, (87), p.53 - 61, 1993/09

None

68 (Records 1-20 displayed on this page)