Dissolution behavior of (U,Zr)O-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

https://doi.org/10.1080/00223131.2014.924445

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 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.

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

https://doi.org/10.1021/ie3013067

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 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 solution.

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.

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

http://www.oldenbourg-link.com/doi/abs/10.1524/rcpr.2011.0028

Solvent cleanup method using activated alumina was discussed in this study. This method was one of candidate to remove TBP/-dodecane degradation products. The degradation sample of 30% TBP/-dodecane was prepared by irradiation (1.6 MGy) using Co -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. 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/-dodecane degradation products were removed and the phase separation performance were improved by the cleanup using activated alumina.

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.

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

http://www.wmsym.org/archives/2006/pdfs/6175.pdf

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.

None

; Pouchon, M. A.; ;

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

https://rdreview.jaea.go.jp/gihou/pdf2/n15-05.pdf

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Sphere bed thermal conductivity

Pouchon, M. A.; ;

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

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Uematsu, Shinichi; ; ; Abe, Tomiyuki; Matsumoto, Mitsuo

Donen Giho, (87), p.53 - 61, 1993/09

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-93-003.pdf

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