Preferential elimination of Ba through irreversible biogenic manganese oxide sequestration

Tani, Yukinori*; Kakinuma, Satomi*; Chang, J.*; Tanaka, Kazuya; Miyata, Naoyuki*

Minerals (Internet), 11(1), p.53_1 - 53_14, 2021/01

https://doi.org/10.3390/min11010053

In this study, we examined the Ba sequestration potential of enzymatically active biogenic Mn oxides (BMOs) with and without exogenous Mn. The BMOs readily oxidized exogenous Mn to produce another BMO phase, and subsequently sequestered Ba at a pH of 7.0, with irreversible Ba sequestration as the dominant pathway. Extended X-ray absorption fine structure spectroscopy and X-ray diffraction analyses demonstrated alteration from turbostratic to tightly stacked birnessite through possible Ba incorporation into the interlayer.

Evaluation of the characteristics of metal nitrate aqueous solutions by microwave heating and the morphologies of synthesized metal oxide powders

Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Fukasawa, Tomonori*; Fukui, Kunihiro*

Funtai Kogakkai-Shi, 57(9), p.485 - 494, 2020/09

In the spent fuel reprocessing process, a mixed solution of uranyl nitrate and plutonium nitrate is converted into mixed oxide powder by the microwave heating. To evaluate the applicability to the industrial-scale and acquire the characteristics data of the microwave heating denitration of various metal nitrate aqueous solutions based on the knowledge studied in the development of laboratory-scale basic experiments, the microwave heating characteristics and metal oxide powder properties were investigated using cerium nitrate, cobalt nitrate and copper nitrate aqueous solutions. The progress rate of the denitration reaction was depended on the position, and the denitration reaction proceeded faster at the periphery than at the center. The morphologies of the synthesized products were porous and hard dry solid with cerium nitrate aqueous solution, foamed dry solid with cobalt nitrate aqueous solution, and powdery particles with copper nitrate aqueous solution. The denitration ratio and average particle size of the synthesized products increased in the order of the cerium nitrate aqueous solution, the cobalt nitrate aqueous solution, and the copper nitrate aqueous solution. The numerical simulations revealed that the periphery of the bottom surface of the metal nitrate aqueous solution was heated by microwaves. This results consistent with the experimental results in which the denitration reaction started from the periphery of the metal nitrate aqueous solution.

Development of ODS tempered martensitic steel for high burn up fuel cladding tube of SFR

Otsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Tachi, Yoshiaki; Kaito, Takeji; Hashidate, Ryuta; Kato, Shoichi; Furukawa, Tomohiro; Ito, Chikara; et al.

2018 GIF Symposium Proceedings (Internet), p.305 - 314, 2020/05

Oxide Dispersion Strengthened (ODS) steel has been developed worldwide as a high-strength and radiation-tolerant steel used for advanced nuclear system. Japan Atomic Energy Agency (JAEA) has been developing ODS steel as the primary candidate material of Sodium cooled Fast Reactor (SFR) high burn-up fuel cladding tube. Application of high burn-up fuel to SFR core can contribute to improvement of economical performance of SFR in conjunction with volume and hazardousness reduction of radioactive waste. This paper described the current status and future prospects of ODS tempered martensitic steel development in JAEA for SFR fuel application.

Negatively charged muonium and related centers in solids

Ito, Takashi; Higemoto, Wataru; Shimomura, Koichiro*

Journal of the Physical Society of Japan, 89(5), p.051007_1 - 051007_8, 2020/05

https://doi.org/10.7566/JPSJ.89.051007

Zeolitic vanadomolybdates as high-performance cathode-active materials for sodium-ion batteries

Zhang, Z,*; Wang, H.*; Yoshikawa, Hirofumi*; Matsumura, Daiju; Hatao, Shuya*; Ishikawa, Satoshi*; Ueda, Wataru*

ACS Applied Materials & Interfaces, 12(5), p.6056 - 6063, 2020/02

https://doi.org/10.1021/acsami.9b19808

Polaronic nature of a muonium-related paramagnetic center in SrTiO

Ito, Takashi; Higemoto, Wataru; Koda, Akihiro*; Shimomura, Koichiro*

Applied Physics Letters, 115(19), p.192103_1 - 192103_4, 2019/11

https://doi.org/10.1063/1.5125919

Study on coordination structure of Re adsorbed on Mg-Al layered double hydroxide using X-ray absorption fine structure

Tanaka, Kazuya; Kozai, Naofumi; Onuki, Toshihiko; Grambow, B.

Journal of Porous Materials, 26(2), p.505 - 511, 2019/04

https://doi.org/10.1007/s10934-018-0634-z

In this study, we utilized X-ray absorption fine structure spectroscopy to clarify the coordination structure of Re in Mg-Al LDH as a surrogate of Tc. Adsorption experiments of ReO on calcined and uncalcined Mg-Al LDHs were conducted in aqueous solutions with different concentrations of NaCl, NaNO, and NaSO. Calcined Mg-Al LDH showed much higher adsorption than uncalcined one. The adsorption of ReO was reversible, and decreased with increasing concentration of competing anions like Cl, NO, or SO. Analysis of Re L-edge extended X-ray absorption fine structure indicated that ReO was adsorbed as an outer-sphere complex on Mg-Al LDH. The observed Re adsorption-desorption behavior, which was sensitive to the presence of competing anions, was consistent with the formation of outer sphere-complex.

Ce substitution and reduction annealing effects on electronic states in PrCeCuO studied by Cu -edge X-ray absorption spectroscopy

Asano, Shun*; Ishii, Kenji*; Matsumura, Daiju; Tsuji, Takuya; Ina, Toshiaki*; Suzuki, Kensuke*; Fujita, Masaki*

Journal of the Physical Society of Japan, 87(9), p.094710_1 - 094710_5, 2018/09

https://doi.org/10.7566/JPSJ.87.094710

Model calculation of Cr dissolution behavior of ODS ferritic steel in high-temperature flowing sodium environment

Otsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kato, Shoichi; Furukawa, Tomohiro; Kaito, Takeji

Journal of Nuclear Materials, 505, p.44 - 53, 2018/07

AA2017-0603.pdf:1.7MB

https://doi.org/10.1016/j.jnucmat.2018.03.054

A calculation model was constructed to systematically study the effects of environmental conditions (i.e. Cr concentration in sodium, test temperature, axial temperature gradient of fuel pin, and sodium flow velocity) on Cr dissolution behavior. Chromium dissolution was largely influenced by small changes in Cr concentration (i.e. chemical potential of Cr) in liquid sodium in the model calculation. Chromium concentration in sodium coolant, therefore, should be recognized as a critical parameter for the prediction and management of Cr dissolution behavior in the sodium-cooled fast reactor (SFR) core. Because the fuel column length showed no impact on dissolution behavior in the model calculation, no significant downstream effects possibly take place in the SFR fuel cladding tube due to the much shorter length compared with sodium loops in the SFR plant and the large axial temperature gradient. The calculated profile of Cr concentration along the wall-thickness direction was consistent with that measured in BOR-60 irradiation test where Cr concentration in sodium bulk flow was set at 0.07 wt ppm in the calculation.

Magnetization, specific heat, O NMR, and Np Mssbauer study of UNpO

Martel, L.*; Hen, A.*; Tokunaga, Yo; Kinnart, F.*; Magnani, N.*; Colineau, E.*; Griveau, J.-C.*; Caciuffo, R.*

Physical Review B, 98(1), p.014410_1 - 014410_8, 2018/07

https://doi.org/10.1103/PhysRevB.98.014410

We report a study of the magnetic and electronic properties of the UNpO solid solution, based on dc- and ac- magnetisation, Np Mssbauer spectroscopy, O Nuclear Magnetic Resonance (NMR), and specific heat measurements. The compound orders antiferromagnetically at T = 17 K. The different techniques reveal the complexity of this system with:(1) a spatial distribution of ordered moments, (2) a small Np ordered moment, and (3) an additional specific heat anomaly at 7.4 K, with a residual value at very low temperature and a reduced magnetic entropy. The results are compared to the end-members of the series, UO and NpO, as well as to the other solid solutions previously reported in this system. We discuss how the properties of UNpO add new input to the trend previously reported for the series, in view of the models that have been previously proposed.