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Journal Articles

Thorium oxide dissolution in HNO$$_{3}$$-HF mixture; Kinetics and mechanism

Simonnet, M.; Barr$'e$, N.*; Drot, R.*; Le Naour, C.*; Sladkov, V.*; Delpech, S.*

Radiochimica Acta, 107(4), p.289 - 297, 2019/04

 Percentile:100(Chemistry, Inorganic & Nuclear)

Journal Articles

Sorption behavior of thorium onto granite and its constituent minerals

Iida, Yoshihisa; Yamaguchi, Tetsuji; Tanaka, Tadao; Hemmi, Ko

Journal of Nuclear Science and Technology, 53(10), p.1573 - 1584, 2016/10

 Times Cited Count:2 Percentile:57.25(Nuclear Science & Technology)

The sorption behavior of thorium (Th) onto granitic rock and its major constituent were investigated by batch sorption experiments. Experiments were carried out under variable pH and carbonate concentrations. Distribution coefficients decreased with increased carbonate concentrations and showed the minimal value at pH 9-10. This sorption tendency was likely due to forming the hydroxide-carbonate complexes of Th in the solutions. The order of sorbability for Th was mica $$>$$ feldspar $$>$$ quartz = granite. The sorption behaviors of Th onto these minerals were analyzed by the triple-layer surface complexation model with the Visual Minteq computer program. The model calculations assuming the inner-sphere surface complexation of Th were able to explain the experimental results reasonably well. It was shown that the sorption behavior of Th onto granite can be explained primarily by the complexation with the surface sites of feldspar.

Journal Articles

Development of simple method to incorporate out-of-core cooling effect on thorium conversion in multi-pass fueled reactor and investigation on characteristics of the effect

Fukaya, Yuji

Annals of Nuclear Energy, 81, p.301 - 305, 2015/07

 Times Cited Count:1 Percentile:81.41(Nuclear Science & Technology)

Development of a simple method to incorporate the out-of-core cooling effect on the thorium conversion in multi-pass fueled reactors and investigation on characteristics of the effect have been performed. For multi-pass fueled reactors, such as Molten Salt Breeder Reactor (MSBR) and Pebble-Bed Modular Reactor (PBMR), fuel moves in the core and exits from the core. The nuclides decay also out of the core, and it should be also considered if it is important for core characteristics. In the present study, $$^{233}$$Pa is considered to evaluate the thorium conversion accurately. To take the effect into account, in the present study, an effective decay constant is proposed to make equilibrium concentration of $$^{233}$$Pa without out-of-core cooling equal to that of out-of-core cooling. With the effective decay constant, the out-of-core cooling effect can be incorporated even with the code system using macroscopic cross sections generated by cell burn-up calculations without any code modification. In addition, the characteristic of out-of-core cooling effect for the thorium conversion is evaluated for thorium fueled reactors of MSBR and PBMR. It is concluded that the out-of-core cooling effect is suitable for MSBR to enhance thorium conversion because of the fast flow rate of fuel salt. On the other hand, the effect is not important and not realistic to employ for PBMR because the in-core residence time of approximately 100 days is longer than the half-life of $$^{233}$$Pa of 27.0 days, and the effect cannot improve the conversion ratio drastically.

Journal Articles

Interactions between anionic complex species of actinides and negatively charged mineral surfaces

Yamaguchi, Tetsuji; Nakayama, Shinichi; Yoshida, Takahiro

Radiochimica Acta, 92(9-11), p.677 - 682, 2004/12

 Times Cited Count:4 Percentile:66.37(Chemistry, Inorganic & Nuclear)

Adsorption of actinides onto negatively charged mineral surfaces was investigated under conditions that actinides were predominantly present as anionic complex species: Th(CO$$_{3}$$)$$_{5}$$$$^{6-}$$, Am(CO$$_{3}$$)$$_{3}$$$$^{3-}$$, Np(CO$$_{3}$$)$$_{2}$$(OH)$$_{2}$$$$^{2-}$$, UO$$_{2}$$(OH)$$_{4}$$$$^{2-}$$, NpO$$_{2}$$(OH)$$_{2}$$$$^{-}$$, Sn(OH)$$_{5}$$$$^{-}$$ and Pb(OH)$$_{3}$$$$^{-}$$. These solutions were left to stand for 2 days to confirm these elements stable in dissolved state, and then contacted with minerals, $$gamma$$-Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$ (AEROSIL, specific surface area: 10$$^{5}$$ m$$^{2}$$ kg$$^{-1}$$). After desired contact time for 2 days or more, the solutions were ultra-filtered through 10$$^{4}$$-molecular-weight cutoff Millipore filters and the concentrations of the elements in the filtrates were determined. The sorption experiments were performed at room temperature (25$$^{circ}$$C) under Ar. Distribution coefficients decreased with the increasing pH and with increasing carbonate concentrations. The monotonous decrease in the distribution coefficients in the investigated pH range suggests that the electrostatic repulsion was a dominant interaction between anionic complex species of actinides and negatively charged mineral surfaces.

Journal Articles

Flow injection extraction chromatography with ICP-MS for thorium and uranium determination in human body fluids

Tolmachyov, S.; Kuwabara, Jun*; Noguchi, Hiroshi

Journal of Radioanalytical and Nuclear Chemistry, 261(1), p.125 - 131, 2004/07

 Times Cited Count:18 Percentile:21.18(Chemistry, Analytical)

A method based on flow injection extraction chromatography coupled with on-line ICP-MS (FI-EC-ICPMS) for simultaneous thorium and uranium determination in human body fluids (urine and blood) has been developed and validated. By using extraction chromatography, the limits of detection for $$^{232}$$Th, $$^{235}$$U and $$^{238}$$U were achieved 0.06 ng l$$^{-1}$$, 0.0014 ng l$$^{-1}$$ and 0.05 ng l$$^{-1}$$, respectively. The FI-EC-ICPMS method accuracy was 102.4% and 101.5% with overall precision (RSDmax at 95% CI) of 5.3% and 4.9% for $$^{232}$$Th and $$^{238}$$U, respectively. The $$^{235}$$U/$$^{238}$$U atom ratio is measured with 1.8% precision. The technique was employed for simultaneous thorium and uranium analyses in human urine and blood samples after microwave digestion.

JAEA Reports

Measurement of doppler effect on resonance materials for ROX fuel using FCA

Ando, Masaki; Nakano, Yoshihiro; Okajima, Shigeaki; Kawasaki, Kenji

JAERI-Research 2003-029, 72 Pages, 2003/12

JAERI-Research-2003-029.pdf:3.41MB

The objectives of this study is to clarify calculation accuracy for the Doppler effect of the resonance materials; erbium (Er), tungsten (W) and thorium (ThO$$_{2}$$). Doppler effect measurements were carried out in a fast neutron spectrum (XX-2 core) and in an intermediate neutron spectrum (XXI-1D2 core) by the sample-heated and reactivity worth measurement method up to 800$$^{circ}$$C using FCA. The experiment was analyzed with the standard analysis method for fast reactor cores at FCA with the use of the JENDL-3.2. The SRAC system was also used to investigate the calculation accuracy of the system and to compare it with that of the FCA standard analysis method. The standard analysis method underestimated for the XX-2 core and agreed the experiments within the experimental errors for the XXI-1D2 core. The analysis with the SRAC system gave smaller values by 3%$$sim$$10% for the Er sample and bigger values by 2%$$sim$$5% for the W sample than the standard analysis method.

JAEA Reports

Evaluations of heavy nuclide data for JENDL-3.3

Kawano, Toshihiko*; Matsunobu, Hiroyuki*; Murata, Toru*; Zukeran, Atsushi*; Nakajima, Yutaka*; Kawai, Masayoshi*; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Osawa, Takaaki*; et al.

JAERI-Research 2003-026, 53 Pages, 2003/12

JAERI-Research-2003-026.pdf:2.48MB

New evaluations of neutron nuclear data for Uranium, Plutonium, and Thorium isotopes which are essential for applications to nuclear technology were carried out for the Japanese Evaluated Nuclear Data Library, JENDL-3.3. The objectives of the current release of JENDL were to fix several problems which have been reported for the previous version, to improve the accuracy of the data, and to evaluate covariances for the important nuclides. Quantities in JENDL-3.2 were extensively re-evaluated or replaced by more reliable values. The heavy nuclide data in JENDL-3.3 were validated with several benchmark tests, and it was reported that the current release gave a good prediction of criticalities.

Journal Articles

Doppler effect measurement on resonance materials for rock-like oxide fuels in an intermediate neutron spectrum

Ando, Masaki; Nakano, Yoshihiro; Okajima, Shigeaki; Kawasaki, Kenji

Journal of Nuclear Materials, 319, p.126 - 130, 2003/06

 Percentile:100

Doppler effect experiments on resonance materials for ROX fuels were carried out to examine the calculation accuracy in the intermediate neutron spectrum using Fast Critical Assembly (FCA) at Japan Atomic Energy Research Institute. This study is the second phase of a series of the Doppler effect experiments on the resonance materials, which is following the measurements in the fast neutron spectrum. The Doppler effect was measured as the sample reactivity change between the heated and unheated samples. The cylindrical samples of the resonance materials such as erbium (Er), tungsten (W) and thorium (ThO$$_{2}$$) were used. The sample was heated up to 800$$^{circ}$$C at the center of the FCA core. The Doppler effect measurements were analyzed using the SRAC 95 code system with the use of JENDL 3.2. The calculated values agreed with the experiment within the experimental error for the W and ThO$$_{2}$$ samples, while the calculation overestimated the experiment for the Er sample about 10 %.

Journal Articles

Extraction and mutual separation of actinide(III), (IV), (V) and (VI) ions by N,N'-dimethyl-N,N'-Dihexyl-3-oxapentanediamide and theroyltrifluoroacetone

Sasaki, Yuji; Choppin, G. R.*

Journal of Radioanalytical and Nuclear Chemistry, 246(2), p.267 - 273, 2000/11

 Times Cited Count:36 Percentile:8.75(Chemistry, Analytical)

no abstracts in English

Journal Articles

Preparation of acid deficient solutions of uranyl nitrate and thorium nitrate by steam denitration

; Takahashi, Yoshihisa

Journal of Nuclear Science and Technology, 33(2), p.147 - 151, 1996/02

 Times Cited Count:1 Percentile:84.43(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Dissolution of ThO$$_{2}$$-based oxides in nitric acid solutions at elevated temperatures

Akabori, Mitsuo; Shiratori, Tetsuo

Journal of Nuclear Science and Technology, 31(6), p.539 - 545, 1994/06

 Times Cited Count:13 Percentile:24.45(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Destruction of weapons-grade plutonium with pebble bed type HTGRs using burner balls and breeder balls

Yamashita, Kiyonobu; *; ; Murata, Isao; Saikusa, Akio

Nippon Genshiryoku Gakkai-Shi, 36(9), p.865 - 868, 1994/00

 Percentile:100(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Analysis of chemical reactivity of burnup molten salts

Ogawa, Toru

JAERI-M 92-210, 92 Pages, 1993/01

JAERI-M-92-210.pdf:1.81MB

no abstracts in English

Journal Articles

Fabrication of very high density fuel pellets of thorium dioxide

Shiratori, Tetsuo; Fukuda, Kosaku

Journal of Nuclear Materials, 202, p.98 - 103, 1993/00

 Times Cited Count:9 Percentile:30.75

no abstracts in English

Journal Articles

Effect of additives on irradiation-induced change of lattice parameter in ThO$$_{2}$$

Akabori, Mitsuo; Fukuda, Kosaku

Journal of Nuclear Science and Technology, 28(9), p.841 - 847, 1991/09

no abstracts in English

Journal Articles

Release behavior of cesium in irradiated(Th,U)O$$_{2}$$

Akabori, Mitsuo; Fukuda, Kosaku

Journal of Nuclear Materials, 186, p.47 - 53, 1991/00

 Times Cited Count:13 Percentile:19.74

no abstracts in English

JAEA Reports

Irradiation performance and integrity of thorium oxide based coated particle fuels at high burnups

Shiratori, Tetsuo; Akabori, Mitsuo; Fukuda, Kosaku; Tsuruta, Harumichi

JAERI-M 90-144, 64 Pages, 1990/09

JAERI-M-90-144.pdf:6.75MB

no abstracts in English

JAEA Reports

Integrity assessment of test fuel assemblies of the High Temperature Engineering Test Reactor

; Shiozawa, Shusaku; Fukuda, Kosaku; Tsuruta, Harumichi; Ikawa, Katsuichi; *; ; Tobita, Tsutomu; Shiratori, Tetsuo; Akabori, Mitsuo; et al.

JAERI-M 90-115, 77 Pages, 1990/07

JAERI-M-90-115.pdf:2.65MB

no abstracts in English

Journal Articles

(Th,U)O$$_{2}$$ powder preparation by freezing method

Ikawa, Katsuichi

21-Seiki No Enerugigen Toshiteno Torichiumu Ni Kansuru Sogo Kenkyu, p.120 - 121, 1990/03

no abstracts in English

JAEA Reports

Irradiation performance of thorium oxide based coated particle fuels

Shiratori, Tetsuo; Ito, Akinori; Akabori, Mitsuo; Shiba, Koreyuki;

JAERI-M 88-220, 61 Pages, 1988/11

JAERI-M-88-220.pdf:4.07MB

no abstracts in English

45 (Records 1-20 displayed on this page)