Crystal structure of frustrated antiferromagnet UNiB

Haga, Yoshinori; Oyamada, Akira*; Matsuda, Tatsuma; Ikeda, Shugo; Onuki, Yoshichika

Physica B; Condensed Matter, 403(5-9), p.900 - 902, 2008/04

https://doi.org/10.1016/j.physb.2007.10.232

Crystal structure of a frustrated antiferomagnet UNiB was investigated precisely by the X-ray diffraction on a Czhochralski-grown high-quality single crystal. The unit cell was unambiguously determined as orthorhombic (space group Cmcm) with the lattice parameters = 6.97, = 17.14, and = 14.89 . These orthorhombic lattice parameters are approximately related to the reported hexagonal unit cell parameters and as = 2, = 2 and =3. They are also consistent with the previously reported weak superlattice reflections measured by the neutron scattering assuming the hexagonal lattice. We have found that four different uranium sites with the different local environment exist. Therefore UNiB can no more be regarded as a pure frustrated system as previously assumed and its magnetic properties should be reanalized based on the correct structure.

The First loading fuel elements and power-up for JRR-2

JRR-2 Control Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.

JAERI 1027, 57 Pages, 1962/09

JAERI-1027.pdf:4.76MB

no abstracts in English

Treatment and analysis of the water and gas in JRR-2

JRR-2 Operations Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Haginoya, Kinichi; Kohayakawa, Toru; Yamaki, Jikei; Yokota, Mitsuo; Horiki, Oichiro; et al.

JAERI 1024, 79 Pages, 1962/08

JAERI-1024.pdf:5.66MB

no abstracts in English

Critical experiments and characteristic measurement for JRR-2

JRR-2 Critical Experiments Group; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.

JAERI 1025, 62 Pages, 1962/03

JAERI-1025.pdf:4.6MB

no abstracts in English

Remote wall thickness measurement of the fuel basket of the dissolver

Yokota, Satoru; Hatanaka, Akira; Fujimori, Masahito; Shimoyamada, Tetsuya; Nakamura, Yoshinobu

no journal, , 

Three batch-type dissolvers in the Tokai Reprocessing Plant are a device for dissolving spent fuel. The dissolver is composed of one slab and two barrels (stainless steel 310s). Install a fuel basket (stainless steel 304L) in the barrel and accept the sheared spent fuel to dissolve it. The insoluble fuel cladding is taken out of the barrels with the basket. The dissolution time of operation for one batch is approximately 10 hours. During dissolution operation, nitric acid was added to the dissolver into the spent fuel in the basket with water. The solution was heated with steam. Corrosion failure has occurred in the past because the dissolver is exposed to a high corrosive environment (high temperature, high acid concentration). Therefore, we carry out the periodical wall thickness measurement of the barrel by the remote control. On the other hand, the wall thickness measurement of the fuel basket was carried out only once by destructive measurement at the time of renewal in 1999. The details of the corrosion tendency of the fuel basket are unknown, and it is urgent to establish a non-destructive measurement method by remote handling. Therefore, we examined the method of wall thickness measurement of the fuel basket and established the measuring technique.