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JAEA Reports

XAFS measurement of simulated waste glass samples (Borosilicate glass including vanadium)

Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.

JAEA-Research 2016-015, 52 Pages, 2016/11

JAEA-Research-2016-015.pdf:37.48MB

The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO$$_{2}$$ crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200$$^{circ}$$C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.

Journal Articles

Impact of mesoscale recirculation of the Kuroshio on asymmetric oceanic structure around Okinawa Island

Uchiyama, Yusuke*; Odani, Sachika*; Yamanishi, Takafumi*; Kamidaira, Yuki; Mitarai, Satoshi*

Doboku Gakkai Rombunshu, B2 (Kaigan Kogaku) (Internet), 72(2), p.I_481 - I_486, 2016/11

no abstracts in English

Journal Articles

Study on corrosion of stainless steel in boiling nitric acid under heat transfer conditions

Ueno, Fumiyoshi; Shiraishi, Hironori; Inoue, Shun; Motooka, Takafumi; Kato, Chiaki; Yamamoto, Masahiro; 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), 8 Pages, 2012/07

In PUREX process for spent fuel reprocessing plants, heating portions in the components are severely corroded in the boiling solution under heat transfer (HT) conditions. In this paper, authors have focused on the effects of surface temperature and heat flux on corrosion rates (CRs) of stainless steels in boiling nitric acid under HT conditions. Two types of cells for HT and immersion conditions were applied for corrosion tests. Test solution used was 33 mol/m$$^{3}$$ vanadium added to 3 kmol/m$$^{3}$$ nitric acid solution, and was heated at boiling temperature under atmospheric pressure. Additionally, a boiling curve which was indicated the relation between heat flux and degree of superheating was investigated experimentally. Surface temperatures during corrosion tests were estimated from a boiling curve. The results showed that CR did not depend on heat flux, but depended on surface temperature. Arrhenius plots on CRs indicated that CR was accelerated by solution boiling against non-boiling.

Journal Articles

Hydrogen absorption of titanium and Ti-5Ta in nitric acid solutions under irradiation

Shiimori, Fusae*; Sakai, Junichi*; Yokoyama, Kenichi*; Motooka, Takafumi; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

Fushoku Boshoku Kyokai Dai-58-Kai Zairyo To Kankyo Toronkai Koenshu, p.13 - 14, 2011/09

In reprocessing plants, hydrogen gas was released by radiolysis of aqueous solution. The relationship of the amount of hydrogen gas and the amount of hydrogen absorption to titanium and Ti-5Ta were not clear. In this study, hydrogen was absorbed to titanium by the cathode charging and irradiation. Then, the amount of the hydrogen gas from solutions and the amount of the hydrogen absorbed to titanium was compared. It was found that a very small amount of the hydrogen by radiolysis was absorbed to titanium. It was suggested that the difference of the hydrogen absorption rate was caused by the difference of the hydrogen concentration on the metal surface.

Oral presentation

Corrosion of SUS304ULC stainless steel at transpassive region in boiling nitric acid solution

Yamamoto, Masahiro; Uchiyama, Yohei; Ueno, Fumiyoshi; Kato, Chiaki; Motooka, Takafumi

no journal, , 

SUS304ULC which had been designed stainless steel was used for a nuclear fuel reprocessing plant. SUS304ULC stainless steel which had been designed to improve the anti-corrosion properties for intergranular corrosion was used for a nuclear fuel reprocessing plant. It has been, however, known that the boiling and/or co-existence of oxidizing ions conditions accelerated the corrosion rates of the material. We examined the electrochemical evaluation of the steel at transpassive region in the boiling nitric acid solution. Although oxygen evolution reaction was influenced by the solutions, metal dissolution reaction was mainly depended by the corrosion potential of the material. Corrosion features were intergranular corrosion and were not influenced by the kinds of solutions. The ratio of the dissolved ions was same as that of the bulk steel composition.

Oral presentation

Study on ageing behavior of reprocessing plants, 1; Long term corrosion of stainless steel in boiling nitric acid at heating portion

Ueno, Fumiyoshi; Kato, Chiaki; Motooka, Takafumi; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

no journal, , 

Long term corrosion of stainless steel in boiling nitric acid solution at heating portion of dissolver and concentrator was studied to investigate ageing behavior of the components in spent fuel reprocessing plant. Corrosion tests carried out more than 8,000 hours in test duration using simulated test solutions including non-radioactive V and Ru ions. As the result, several simulated corrosion data which were equivalent and accelerated about three times of corrosion rate in comparison with actual components were obtained. And it was considered that loss of thickness caused by intergranular corrosion increases as approximately constant rate in stainless steel components but acceleration of corrosion could be observed in the case of remarkable loss of thickness.

Oral presentation

Study on ageing behavior of reprocessing plants, 4; Corrosion behavior of stainless steel under denitration with formaldehyde

Motooka, Takafumi; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

no journal, , 

The corrosion behavior of stainless steels under denitration condition with formaldehyde was investigated by the corrosion test etc. As a result, the decrease in nitric acid concentration and the generation of NOx gas were observed under the denitration. The corrosion rate of stainless steels has decreased greatly by the injection of formaldehyde. It was thought that NOx and nitrous acid were factors for decrease of corrosion rate in a stainless steel.

Oral presentation

Study on ageing behavior of peprocessing plants, 8; Hydrogen formation by Irradiation and hydrogen adsorption of titanium in nitrate solutions

Motooka, Takafumi; Yamamoto, Masahiro; Ueno, Fumiyoshi; Ishijima, Yasuhiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*; Sakai, Junichi*; Shiimori, Fusae*; Miyasaka, Yuto*

no journal, , 

As a part of studies on ageing behavior of reprocessing plants, the amount of hydrogen gas generated from nitrate solutions under $$gamma$$ irradiation and the amount of hydrogen absorbed to titanium alloy were measured after $$gamma$$ irradiation in order to evaluate the hydrogen degradation of instruments made of titanium alloy. The amount of hydrogen gas was decreased with increase of nitrate concentration. Only a little hydrogen was absorbed to titanium. It is necessary to consider the long-time prediction model for hydrogen adsorption to evaluate hydrogen degradation.

Oral presentation

Study on ageing behavior of reprocessing plants, 5; Effect of surface temperature and solution boiling on corrosion behavior of stainless steel in nitric acid solution

Ueno, Fumiyoshi; Shiraishi, Hironori; Inoue, Shun; Motooka, Takafumi; Kato, Chiaki; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

no journal, , 

Effect of metal surface temperature and solution boiling on corrosion of stainless steel in boiling nitric acid solution at heating portion was studied to investigate ageing behavior of the components in spent fuel reprocessing plant. Corrosion tests under the conditions of heat transfer and immersion in atmospheric pressure were carried out using nitric acid solution including Vanadium. As the results, apparent activation energies of thermal dependences on corrosion rates of both the heat transfer and the immersion were indicated approximately 40 kJ/mol. Corrosion rate under the boiling condition were higher about 7 times for the non-boiling condition.

Oral presentation

Corrosion simulation of SUS310Nb in boiling nitric acid solution using cellular automata method

Igarashi, Takahiro; Motooka, Takafumi; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*

no journal, , 

no abstracts in English

Oral presentation

Hydrogen absorption behavior of titanium alloys by cathodic polarization

Ishijima, Yasuhiro; Motooka, Takafumi; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Sakai, Junichi*; Yokoyama, Kenichi*; Tada, Eiji*; Tsuru, Toru*; Nojima, Yasuo*; et al.

no journal, , 

Titanium and Ti-5mass%Ta alloy has been utilized in nuclear fuel reprocessing plant material because of its superior corrosion resistance in nitric acid solutions. However, Ti alloy have been known to high susceptibility of hydrogen embrittlement. To evaluate properties of hydrogen absorption and hydrogen embrittlement of Ti alloys, cathodic polarization tests and slow strain rate tests (SSRT) under cathodic polarization were carried out. Results show titanium hydrides covered on the surface of metals and hydrides thickness were within $$mu$$m. Ti and Ti-5%Ta did not show hydrogen embrittlement by SSRT under cathodic charging. These results suggested that Ti and Ti-5%Ta could absorb hydrogen. But hydrogen did not penetrate inner portion of the metals more than $$mu$$m in depth because titanium hydrides act as barrier of hydrogen diffusion. It is considered that retardation of hydrogen diffusion hindered hydrogen embrittlement of Ti and Ti-5%Ta alloys.

Oral presentation

Structural analysis of Eu complex in adsorbent for MA recovery

Katai, Yuya*; Watanabe, So; Sano, Yuichi; Abe, Ryoji*; Sakurai, Tomoaki*; Arai, Tsuyoshi*; Uchiyama, Takafumi*; Matsuura, Haruaki*

no journal, , 

no abstracts in English

12 (Records 1-12 displayed on this page)
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