Anisotropic thermal lattice expansion and crystallographic structure of strontium aluminide within Al-10Sr alloy as measured by in-situ neutron diffraction

Liss, K.-D.*; Harjo, S.; Kawasaki, Takuro; Aizawa, Kazuya; Xu, P. G.

Journal of Alloys and Compounds, 869, p.159232_1 - 159232_9, 2021/07

https://doi.org/10.1016/j.jallcom.2021.159232

Effect of nitrous ion on oxidation of oxidizing-metallic ion in nitric acid solution

Irisawa, Eriko; Seki, Masaharu*; Ueno, Fumiyoshi; Kato, Chiaki; Motooka, Takafumi; Abe, Hitoshi

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1108 - 1112, 2015/09

Influence of seawater-component on corrosion of steel in nitric acid solution containing vanadium and ruthenium

Irisawa, Eriko; Ueno, Fumiyoshi; Uchida, Naoki; Taguchi, Katsuya

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 3 Pages, 2015/05

Diffusion of tritium in intermetallic compound -LiAl; Relation to the defect structure

Sugai, Hiroyuki

Solid State Ionics, 177(39-40), p.3507 - 3512, 2007/01

https://doi.org/10.1016/j.ssi.2006.10.012

The diffusion coefficients and its activation energy (103.79.5 kJ/mol) for tritium in intermetallic compound -LiAl are determined at temperatures from 699 to 886 K. Though the present result for the diffusion coefficient is almost the same as that reported earlier, the activation energy turns out nearly twice of that (64.93.8 kJ/mol) reported earlier. On the basis of the crystal structure and defect structure, the large activation energy of this study suggest that tritium diffuses interstitially and is impeded by an attractive interaction with lithium atoms in lithium sublattices.

Rapid dissolution techniques with microwave heating devices for solidified products made from non-metallic wastes by plasma melting

Haraga, Tomoko; Kameo, Yutaka; Nakashima, Mikio

Bunseki Kagaku, 55(1), p.51 - 54, 2006/01

https://doi.org/10.2116/bunsekikagaku.55.51

A relatively large quantity of sample solutions have to be prepared for radiochemical analysis of solidified products yielded by plasma melting treatment of non-metallic radioactive wastes. In order to dissolve the solidified products sample rapidly, dissolution method with microwave heating devices was applied. In a conventional method only by external heating with various mixtures of acids (HNO, HF, HClO and HSO), a 0.1 g amount of the sample was dissolved with difficulty. However, applying the microwave assisted dissolution method, a 1 g amount of the sample was completely dissolved in a shorter time. Thereby the time for dissolution procedures was shortened less than a one-tenth. The present dissolution method was successfully applied to the blast furnace slag as a reference material to determine main elements with good precision.

Numerical analysis of fractional distillation characteristics for radioactive metallic waste vaporized in the shape of atomic beam

Akaoka, Katsuaki; Maruyama, Yoichiro

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(2), p.127 - 134, 2005/06

https://doi.org/10.3327/taesj2002.4.127

The fractional distillation characteristics of the materials used for the reactor pressure vessel made of ASTM A302B and the structures in reactor made of SUS304 which are the radioactive metallic waste of Japan Power Demonstration Reactor (JPDR) were analyzed numerically. In the simulation, the vaporization rates of the components of the waste were calculated by using the Langmuir's equation and Henry's law. As the result of simulation, it was calculated that Eu, Eu, C and Nb can be reduced to less than clearance level by the fractional distillation. On the ASTM A302B case, it was pointed out that the other radioactive nuclei which are Mn, Fe, Co, Ni and Ni satisfy clearance level after 77 years cooling down. On the SUS304 case, it was pointed out that Ni and Ni must be separated to satisfy clearance level using isotope separation.

Sedimentation of substitutional solute atoms in intermetallic compound of Bi-Pb system under ultra-strong gravitational field

Ono, Masao; Huang, X.*; Kinoshita, Takahiro*; Ueno, Hideto*; Osakabe, Toyotaka; Mashimo, Tsutomu

Defect and Diffusion Forum, 237-240(2), p.1101 - 1104, 2005/00

Ultra-strong gravitational field can induce sedimentation of even atoms in condensed matter. We had realized sedimentation of substitutional solute atoms in some miscible alloys. How about in the other alloys? So, In this study, the ultra-centrifuge experiments were performed on an intermetallic compound of Bi-Pb system (BiPb) by changing time duration of experiment time (experimental conditions; maximum centrifugal force: 1.010g level, temperature: 130-150 C, duration: 30-150h, state: solid). Composition changes were observed in the centrifuged samples. And, it was found that the Bi phase appeared from starting state of BiPb around the weak gravitational field region of the sample. These results showed that sedimentation of substitutional solute atoms occurred, and induced the structure change in intermetallic compounds.

Heat transfer characteristics of the steam reformer in the HTTR hydrogen production system

Takeda, Tetsuaki

Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 4 Pages, 2004/00

no abstracts in English

Electro-deposition of tantalum on tungsten and nickel in LiF-NaF-CaF melt containing KTaF; Electrochemical study

Mehmood, M.*; Kawaguchi, Nobuaki*; Maekawa, Hideki*; Sato, Yuzuru*; Yamamura, Tsutomu*; Kawai, Masayoshi*; Kikuchi, Kenji

Materials Transactions, 44(2), p.259 - 267, 2003/02

https://doi.org/10.2320/matertrans.44.259

Electrochemical study has been carried out on the electro-deposition of tantalum in LiF-NaF-CaF melt containing KTaF at 700C. This has been done for determining the mechanistic features for preparing electrolytic coating of tantalum on nickel and tungsten substrates. Electro-deposition of metallic tantalum occurs primarily by electro-reduction of Ta(V). Pure metallic tantalum without any entrapped salt is successfully deposited on tungsten by galvanostatic polarization at reasonably low current densities. An additional feature on nickel is the formation of an intermetallic compound at potential 0.25V nobler than that of pure tantalum as a result of underpotential deposition of tantalum. This intermetallic compound covers the surface within a short time followed by deposition of pure tantalum, although intermetallic compound keeps growing at the interface of pure tantalum deposit and the substrate as a result of diffusion.

Status report on the JAERI AVF cyclotron system

Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Tamura, Hiroyuki; Kurashima, Satoshi; Yokota, Wataru; Okumura, Susumu; Fukuda, Mitsuhiro; Arakawa, Kazuo

AIP Conference Proceedings 600, p.129 - 132, 2001/00

https://doi.org/10.1063/1.1435216

The AVF cyclotron system at JAERI Takasaki has been smoothly operated without serious troubles since the first beam extraction of 50 MeV 4He2+ in March 1991. A yearly operation time is about 3200 hours on an average for past several years. In last three years, we performed some improvements and developments as followings: stabilization of the cyclotron beam, renewal of the control computers and basic programs, installation of a new ECR ion source and reconstruction of the rotary shutter. Furthermore, cocktail beams of series M/Q=4 and M/Q=2 have been developed continuously. Now we are modifying the RF cavity for the flat-top acceleration by the addition of 5th harmonic frequency.