Mechanical properties of pure tungsten and tantalum irradiated by protons and neutrons at the Swiss spallation-neutron source

Saito, Shigeru; Suzuki, Kazuhiro; Obata, Hiroki; Dai, Y.*

Nuclear Materials and Energy (Internet), 34, p.101338_1 - 101338_9, 2023/03

https://doi.org/10.1016/j.nme.2022.101338

In this study, a post-irradiation examination of pure tungsten (W) and tantalum (Ta) specimens irradiated at the Swiss Spallation-Neutron Source is conducted. W is used as a potential candidate for a solid spallation-target material owing to its favorable properties. However, W also suffers from several disadvantages such as poor corrosion resistance to water coolant and irradiation embrittlement. To improve these properties, cladding technologies using Ta for W alloys have been developed. In the present study, we investigated the irradiation effects on two tungsten materials, poly-crystal W (W-Poly) and single-crystal W (W-Sin), along with pure polycrystalline Ta. The tensile-test results revealed that W-Poly exhibited almost no ductility after irradiation of 10.2-35.0 dpa. W-Sin was irradiated up to 10.2 dpa and demonstrated 6% of total elongation (TE). With regard to Ta, TE decreased based on the increase in irradiation, reaching almost zero at doses of more than 10.3 dpa.

Experimental validation of tensile properties measured with thick samples taken from MEGAPIE target

Saito, Shigeru; Suzuki, Kazuhiro; Hatakeyama, Yuichi; Suzuki, Miho; Dai, Y.*

Journal of Nuclear Materials, 534, p.152146_1 - 152146_16, 2020/06

https://doi.org/10.1016/j.jnucmat.2020.152146

A post-irradiation examination (PIE) was performed on the tensile specimens prepared from the MEGAPIE (MEGAwatt Pilot Experiment) target which were irradiated in flowing lead-bismuth eutectic (LBE). Thicknesses of the specimens were over two times larger than that of the standard specimen. The PIE revealed that the T91 specimens showed a 1.5-2.0 times larger total elongation (TE) compared to the literature values for a specimen with standard t/w (ratio of thickness to width). It could be suggested that the t/w and TE were strongly correlated. Then, we tried to investigate the effects of the t/w on the TE by comparing unirradiated specimens. We found that there was no t/w dependence on the strength and uniform elongation. On the other hand, the TE increases with increasing t/w. Based on the experimental data, we correlated the TE with various specimens t/w to estimate appropriate TE values, including that for the standard specimen.

Mineralogical analysis and dating using the JEOL JXA-8530F FE-EPMA at the JAEA Tono Geoscience Center

Shimizu, Mayuko; Sano, Naomi; Suzuki, Kazuhiro

Nagoya Daigaku Nendai Sokutei Kenkyu, 1, p.36 - 43, 2017/03

http://www.nendai.nagoya-u.ac.jp/nubcr/2016/036-043_2016.pdf

We established a CHIME monazite dating method using R = 100 mm spectrometers and a provenance analysis method using heavy minerals for the dating and analysis of minerals. CHIME dating has traditionally been performed with conventional R = 140 mm spectrometers for measurement of U, Th, and Pb. These spectrometers, however, have low count rates in measurements of Pb. We used a JEOL JXA-8530F FE-EPMA equipped with R = 100 mm spectrometers, a system installed at Tono Geoscience Center in 2014, for the CHIME dating of monazite. We corrected the spectral interferences peculiar to R = 100 mm spectrometers by the method of AA mli and Griffin (1975) for monazite analyses. We calculated the correction factors by a new interference correction method using natural monazites. We also established a quick quantitative analysis and identification method for heavy minerals using the EPMA.

Development of specimen preparation techniques for pitting potential measurement of irradiated fuel cladding tubes

Suzuki, Kazuhiro; Motooka, Takafumi; Tsukada, Takashi; Terakawa, Yuto; Ichise, Kenichi; Numata, Masami; Kikuchi, Hiroyuki

JAEA-Technology 2014-004, 29 Pages, 2014/03

JAEA-Technology-2014-004.pdf:3.66MB

By the effect of the Great East Japan Earthquake, seawater was injected into spent fuel pools in unit 2, 3 and 4 at Fukushima Daiichi Nuclear Plant in order to cool spent fuels. It is known that chloride ion contained in seawater could cause pitting corrosion for metallic materials. It was concerned that radioactive products inside of fuel cladding tubes might be escaped through the pits. Therefore we have investigated the pit initiation condition of fuel cladding tubes by measuring pitting potential in order to evaluate stability of the enclosure function of fuel cladding tubes in spent fuel pools containing sea salt. In this report, we describe the development of specimen preparation techniques for pitting measurement of spent fuel cladding tubes having high radioactivity. By accomplishing of the development of the specimen preparation techniques, we could evaluate pit initiation condition of spent fuel cladding tubes in water containing sea salt.

None

Suzuki, Kazuhiro*; Yoshida, Hidekazu;

Nagoya Daigaku Rigakubu Kiyo, , 

None

Behavior of high burnup fuels under Reactivity-Initiated Accident (RIA) and Loss-of-Coolant Accident (LOCA) conditions, 2; PCMI failure in an RIA

Sugiyama, Tomoyuki; Sasajima, Hideo; Nagase, Fumihisa; Fuketa, Toyoshi; Kamoshida, Shigeo; Suzuki, Kazuhiro

no journal, , 

no abstracts in English

Development of volume reduction equipment for radioactive waste

Ichise, Kenichi; Sakuraba, Naotoshi; Suzuki, Kazuhiro; Miyata, Seiichi; Komiya, Tomokazu; Nishi, Masahiro; Kitagawa, Isamu; Numata, Masami

no journal, , 

As a part of measures to reduce radioactive wastes, which are generated during operation and maintenance of Waste Safety Testing Facility (WASTEF), we developed volume reduction equipment for and wastes. In this presentation, we report manufacture of an experimental model, its operativeness & verification of reduction effect in a mock-up test, improvements, and application to actual radioactive wastes.

Research for the improvement of SCC evaluation method including the effect of radiation on water, 3; Influence of materials and dissolved oxygen related to oxide film structures on stainless steel under -ray irradiation in high temperature water

Yamamoto, Masahiro; Nakahara, Yukio; Kato, Chiaki; Tsukada, Takashi; Suzuki, Kazuhiro; Hatakeyama, Yuichi; Watanabe, Atsushi*; Fuse, Motomasa*

no journal, , 

It is well known that the decomposition of water by irradiation results in the formation of oxidants, such as hydrogen peroxide (HO) and radical species. The oxidant such as HO promote nobler electrochemical corrosion potential (ECP) of stainless steels (SSs) and change oxide instructors as corrosion products on stainless steels surface. In this work, the effects of -ray irradiation and structure on the corrosion of Type 316L SS and 304L SS in high-temperature water of 288C were examined. We also consider structures of the oxide film on the stainless steel using transmission electron microscope (TEM) and Raman spectroscope in order to show the differences made by the irradiation and structure. In addition, the effect of diffusion restriction and surface reactions may become more significant Inside crevices, so that the environments are expected to be different from those in the outsides.

Measurement of pitting potential of irradiated zircaloy-2 cladding tube in diluted artificial seawater, 1; Development of specimen preparation techniques for pitting potential measurement

Suzuki, Kazuhiro; Motooka, Takafumi; Tsukada, Takashi; Terakawa, Yuto; Ichise, Kenichi; Numata, Masami; Kikuchi, Hiroyuki

no journal, , 

no abstracts in English

Measurement of pitting potential of irradiated fuel cladding in diluted artificial seawater

Komatsu, Atsushi; Motooka, Takafumi; Suzuki, Kazuhiro; Terakawa, Yuto; Numata, Masami; Kikuchi, Hiroyuki; Tsukada, Takashi

no journal, , 

Pitting potential of irradiated fuel cladding tube (Zry-2) was measured in diluted artificial seawater. The pitting potential was higher than that of non-irradiated Zry-2. Pitting corrosion was inhibited by the oxide film formed during irradiation, since scratches on the surface affect pitting potential.