Laser beam direct energy deposition of graded austenitic-to-martensitic steel junctions compared to dissimilar electron beam welding

Villaret, F.*; Boulnat, X.*; Aubry, P.*; Yano, Yasuhide; Otsuka, Satoshi; Fabregue, D.*; de Carlan, Y.*

Materials Science & Engineering A, 824, p.141794_1 - 141794_10, 2021/09

https://doi.org/10.1016/j.msea.2021.141794

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 coefficient and its activation energy (116.3 11.7 kJ/mol) of tritium in an intermetallic compound -LiAl are determined at temperatures from 700 to 848 K. Though the present result for the diffusion coefficient is almost the same as that reported previously, the present result for the activation energy turns out nearly twice of that (64.9 3.8 kJ/mol). The present result for the activation energy is consistent with the systematics that an increase of lithium concentration in Al-Li systems increases the activation energy, but the previous result is not. Furthermore, a consideration of the crystal structure and defect structure suggests that tritium diffuses and is impeded by the attractive interaction with lithium atom at lithium sublattices.

Positron lifetime measurement on centrifuged BiPb intermetallic compound

Ono, Masao; Huang, X. S.*; Shibata, Yasuhiro*; Iguchi, Yusuke*; Sakai, Seiji; Maekawa, Masaki; Chen, Z. Q.*; Osakabe, Toyotaka; Kawasuso, Atsuo; Naramoto, Hiroshi*; et al.

Proceedings of 1st International Conference on Diffusion in Solids and Liquids (DSL 2005), p.531 - 533, 2005/07

Recently, we formed atomic-scale graded structures in some miscible alloys and observed the decomposition in BiPb intermetallic compound by sedimentation of atoms under strong gravitational field. In this study, we measured positron lifetime of centrifuged BiPb, to which the composition change was very small as it was treated at low temperature. It was found that the positron lifetime became longer than that of starting state. This indicated that the point defects (vacancy or divacancy) increased in the sample by centrifugal treatment. We are now investigating the relationship between increase in point defects and sedimentation of atoms.

Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450C and 550C

Kurata, Yuji; Futakawa, Masatoshi; Saito, Shigeru

JAERI-Research 2005-002, 37 Pages, 2005/02

JAERI-Research-2005-002.pdf:20.04MB

Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450C and 550C for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450C with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450C. The corrosion depth of ferritic/martensitic steels also decreases at 550C with increasing Cr content whereas the corrosion depth of austenitic steels, JPCA and 316ss becomes larger due to ferritization caused by dissolution of Ni at 550C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr.

Report of Examination of the Sample from Core Shroud (2F2-H3) at Fukushima Dai-ni Power Station Unit-2 (Contract research)

The Working Team for Examination of the Sample from Core Shrouds and Primary Loop Recirculation Pipi; Nakajima, Hajime*; Shibata, Katsuyuki; Tsukada, Takashi; Suzuki, Masahide; Kiuchi, Kiyoshi; Kaji, Yoshiyuki; Kikuchi, Masahiko; Ueno, Fumiyoshi; Nakano, Junichi; et al.

JAERI-Tech 2004-015, 114 Pages, 2004/03

JAERI-Tech-2004-015.pdf:38.06MB

The Tokyo Electric Power Company (TEPCO) visually inspected the weld joint of core shroud at Fukushima Dai-ni Nuclear Power Station Unit-2 by a direction of the Nuclear and Industrial Agency, cracks were observed at outer side of the ring weld joint (H3) between a core shroud middle trunk and a middle ring. TEPCO has conducted a material examination with Nippon Nuclear Fuel Development Co. Ltd. (NFD) on the specimen including cracks sampled from the core shroud. The present examination has been performed with the objective to independently investigate and evaluate the materials by jointly attending the examination with NFD from the planning stage. Based on results of the present examination, the probable presence of tensile residual stress by welding process and dissolved oxygen contents in the cooling water, it was shown that the cracks were considered to be stress corrosion cracking (SCC). However, the cause of the cracks needs more consideration on the way of shroud construction.

Phonon density of states in SrFeCoO and SrBaFeCoO; Effects induced by magnetic order and transport coherence

Rykov, A. I.*; Nomura, Kiyoshi*; Sawada, Tsuguo*; Mitsui, Takaya; Seto, Makoto*; Tamegai, Tsuyoshi*; Tokunaga, Masashi*

Physical Review B, 68(22), p.224401_1 - 224401_7, 2003/12

https://doi.org/10.1103/PhysRevB.68.224401

no abstracts in English

Clearance levels derived by European Commission

Okoshi, Minoru

Dekomisshoningu Giho, (26), p.2 - 12, 2002/11

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_26.pdf

The concept of clearance has been introduced by the International Atomic Energy Agency in 1996 and is very useful for the management of very low-level solid materials generating from the decommissioning of nuclear facilities. Therefore, the European Commission (EC) derived the specific clearance levels for metals, buildings and building rubble in RP 89 and 113, respectively. The EC also derived the general clearance levels for all solid materials generating from the regulated facilities in RP 122. Comparing the clearance levels of Japan with the unrounded levels of EC, the differences of levels are small. The biggest difference is found in Fe-55 and the EC's clearance level is about one fifth of Japanese clearance level. This is caused because the EC considers the direct ingestion of cleared building rubble by children and used the conservative ingestion rate of it. EC's discussions related to the clearance levels are very useful for Japan to derive our own clearance levels and to clear materials from regulatory control.

Moessbauer spectroscopy of Cs following the decay of Xe atoms implanted in metals

*; *; *; *; *; *; Muto, Suguru*; Koizumi, Mitsuo; Osa, Akihiko; Sekine, Toshiaki; et al.

Journal of Radioanalytical and Nuclear Chemistry, 239(2), p.251 - 255, 1999/00

https://doi.org/10.1007/BF02349492

no abstracts in English

Neptunium-iron phase diagram

J.K.Gibson*; R.G.Haire*; E.C.Beahm*; M.M.Gensini*; Maeda, Atsushi; Ogawa, Toru

Journal of Nuclear Materials, 211, p.215 - 222, 1994/00

https://doi.org/10.1016/0022-3115(94)90349-2

no abstracts in English

Fundamental research on radioactive metal melting

Nakamura, Hisashi; Kanazawa, Katsuo; Sato, Takayuki; ; Fujiki, Kazuo

Dekomisshoningu Giho, (9), p.41 - 50, 1993/12

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_09.pdf

no abstracts in English