Development of field emission SEM to observe high radioactive irradiated fuels

Isozaki, Misaki; Sasaki, Shinji; Maeda, Koji; Katsuyama, Kozo

JAEA-Technology 2015-058, 28 Pages, 2016/03

JAEA-Technology-2015-058.pdf:23.51MB

During irradiation in the fast reactor "JOYO", the changes of fuel structures with the formation of central void occur in the uranium-plutonium mixed oxide fuels (MOX fuels) because of radial temperature gradient. The changes of element (U, Pu, and so on) distributions along radial direction proceed from these changes. Therefore, it is important to study the changes of fuel structures of the minute area in fuel pellet and the changes of element distribution behavior for development of fast reactor fuels. In order to make detailed observations of microstructure and elemental analyses of fuel samples, a field emission scanning electron microscope (FE-SEM) equipped with a wavelength-dispersive X-ray spectrometer (WDS) and an energy-dispersive X-ray spectrometer (EDS) were installed in Fuel Monitoring Facility (FMF). The samples of this FE-SEM are very high radioactivity because the samples contain the nuclear fuel elements (U, Pu, etc.), the fission products (Cs, Rh, etc.) and activation product (Co, Mn etc.). Owing to this, it is necessary to prevent leakage of radioactive materials (particularly, U, Pu is need tight accountancy in law) and to protect operators from radiation. In this installation of FE-SEM, it is selected JSM-7001F (made by JEOL) for base model. The notable modified points were as follows. (1) To protect operators from radiation, lead shields was installed around FE-SEM. (2) To prevent leakage of radioactive materials, the instrument was attached to a remote control air-tight sample transfer unit between a shielded hot cell and the FE-SEM and the instrument was fixing rigid structure without vibration damper. (3) The design and manufacture the lead shields with consideration of instrument maintainability. This paper was described the summary of FE-SEM, the notable modified points, the ways of FE-SEM installation, the result of performance test.

Occurrence and potential activity of denitrifiers and methanogens in groundwater at 140 m depth in Pliocene diatomaceous mudstone of northern Japan

Katsuyama, Chie*; Nashimoto, Hiroaki*; Nagaosa, Kazuyo*; Ishibashi, Tomotaka*; Furuta, Kazuki*; Kinoshita, Takeshi*; Yoshikawa, Hideki; Aoki, Kazuhiro; Asano, Takahiro*; Sasaki, Yoshito; et al.

FEMS Microbiology Ecology, 86(3), p.532 - 543, 2013/12

https://doi.org/10.1111/1574-6941.12179

Anaerobic microbial activity has a major influence on the subsurface environment, and should be considered in subsurface activities including the construction of radioactive waste repositories. We investigated denitrification and methanogenesis in anoxic groundwater from 140 m depth in two boreholes, where the redox potential fluctuated. The average maximum potential denitrification rates, measured under anaerobic conditions in the two boreholes using an N tracer. Methanogenesis candidates were detected by 16S rRNA gene analysis. Although the stable isotope signatures suggested that some of the dissolved methane was of biogenic origin, no potential for methane production was evident during the incubations. The groundwater at 140 m depth did not contain oxygen, had an Eh ranging from -144 to 6.8 mV, and was found to be a potential field for denitrification.

Development and design of the negative-ion-based NBI for JT-60 Super Advanced

Hanada, Masaya; Akino, Noboru; Endo, Yasuei; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Kojima, Atsushi; Mogaki, Kazuhiko; et al.

Journal of Plasma and Fusion Research SERIES, Vol.9, p.208 - 213, 2010/08

http://www.jspf.or.jp/JPFRS/PDF/Vol9/jpfrs2010_09-207.pdf

A large negative ion source with an ion extraction area of 110 cm 45 cm has been developed to produce 500 keV, 22 A D ion beams required for JT-60 Super Advanced. To realize the JT-60SA negative ion source, the JT-60 negative ion source has been modified and tested on the negative-ion-based neutral beam injector on JT-60U. A 500 keV H ion beam has been produced at 3 A without a significant degradation of beam optics. This is the first demonstration of a high energy negative ion acceleration of more than one-ampere to 500 keV in the world. The beam current density of 90 A/m is being increased to meet 130 A/m of the design value for JT-60SA by tuning the operation parameters. A long pulse injection of 30 s has been achieved at a injection D power of 3 MW. The injection energy, defined as the product of the injection time and power, reaches 80 MJ by neutralizing a 340 keV, 27 A D ion beam produced with two negative ion sources.

Beam-palarization asymmetries for the (,) and (,) reactions for =1.5-2.4 GeV

Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.

Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08

https://doi.org/10.1103/PhysRevLett.91.092001

no abstracts in English

Post irradiation-examination results for absorber material irradiation rig AMIR-6; The Results of non-destructive examination for capsules

Abe, Kazuyuki; Sasaki, Shinji; Kikuchi, Shin; Katsuyama, Kozo; Nagamine, Tsuyoshi; Matsumoto, Shinichiro

JNC TN9430 2002-003, 52 Pages, 2002/05

JNC-TN9430-2002-003.pdf:2.98MB

Irradiation tests of Absorber Material Irradiation Rig (AMIR) have been continuously conducted, using the experimental fast reactor Joyo. AMIR-6, which was submitted for post-irradiation-examinations (PIE) this time, was irradiated in order to evaluate the limit of failure in control rods and confirm the effect of method for suppression of relocation caused by cracking of boron carbide (BC) pellets. According to this purpose, gap size between BC pellet and cladding tube (inner capsule tube), enrichment of B, thickness of cladding tube and its material were changed in this test. In addition, thin shroud tube wrapping BC pellets was used as the method for suppression of relocation. Capsules were loaded in compartments, which had the upper and lower stairs, and irradiation rig AMIR-6 was constructed of seven compartments in total. The irradiation capsule had double tubes, namely inner capsule tube and outer capsule tube. Between these tubes, sodium was filled. AMIR-6 was irradiated at the 6 raw in Joyo Mark-II core up to 10610 cap/m (max. burn-up) and 3.8210 n/m (max, fluence). Irradiation temperatures were evaluated from 530 to 890 C in design. Extraordinary results were observed for lower capsules by weight measurement performed. So, detailed visual inspection was carried out for these capsules. Consequently, sodium entered from the crack of screwhead attached to the outer tube in three irradiation capsules, whose weight increased. It was recognized that the sodium level between cladding tube and outer tube was lower in six capsules of lower stairs. Cladding crack was found out in three cladding tubes of lower irradiation capsule. It was suggested that the crack become for decrease of strength of cladding tube because those temperature increased at the position where sodium was not filled. The irradiation capsule using a shroud tube showed no diameter increase and ovality in the cladding.

High linear power irradiation tests with Am-MOX fuels, 5; Observation of fuel microstructure

Maeda, Koji; Sasaki, Shinji; Katsuyama, Kozo; Donomae, Takako; Osato, Yukihiro*; Onuma, Yasuhiro*; Nukaga, Sadayoshi*

no journal, , 

no abstracts in English

Denitrification in groundwater at 140 m depth in sedimentary horizon

Katsuyama, Chie*; Nashimoto, Hiroaki*; Ishibashi, Tomotaka*; Furuta, Kazuki*; Nagaosa, Kazuyo*; Yoshikawa, Hideki; Asano, Takahiro; Sasaki, Yoshito; Aoki, Kazuhiro; Suwa, Yuichi*; et al.

no journal, , 

no abstracts in English

Fabrication and evaluation of light-emitting SiO substrate co-implanted with Si and C ions

Kikuchi, Shusuke*; Umenyi, A. V.*; Inada, Kazuki*; Kawashima, Akihiro*; Noguchi, Katsuya*; Sasaki, Tomoyuki*; Miura, Kenta*; Hanaizumi, Osamu*; Yamamoto, Shunya; Kawaguchi, Kazuhiro; et al.

no journal, , 

Light emission around a wavelength () of 500 nm from SiO substrates implanted with Si and C ions and annealed at 1100C has been reported. In this report, we investigated photoluminescence (PL) properties of SiO substrates implanted with Si and C ions and annealed at the lower temperature of 700C. PL peaks by Si-ion implantation were observed around = 650 nm, and PL peaks by C-ion implantation were observed around = 450 nm from SiO substrates annealed at 700C. The PL peak wavelength became shorter by increasing the ratio of C to Si ions. Consequently, it was confirmed that it is possible to control the emission wavelength by the ratio of C to Si ions. Our samples showed typical light-emission though the annealing temperature was lower than the temperature reported by other groups.

Development of remote decontamination techniques for reactor building, 8; Analysis of Concrete core sample from Operation Floor of Unit 2

Higashiuchi, Atsushi; Maeda, Koji; Otani, Akira; Sasaki, Shinji; Katsuyama, Kozo; Chigira, Takayuki*; Murata, Hirotoshi*

no journal, , 

no abstracts in English

Irradiation behavior of sodium bonded type control rod in the fast reactor, 3 Visual inspection and profilometry results of absorber pins

Sasaki, Shinji; Ishimi, Akihiro; Katsuyama, Kozo; Maeda, Koji; Sogame, Motomu

no journal, , 

no abstracts in English