Development of -ray visualization survey meter in high gamma and neutron background environment

Tsubota, Yoichi; Kobayashi, Kenji; Ishii, Tatsuya; Hirato, Misaki; Shioya, Satoshi; Nakagawa, Takahiro

Radiation Protection Dosimetry, 200(16-18), p.1676 - 1680, 2024/11

https://doi.org/10.1093/rpd/ncae169

In the decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS, 1F), workers are removing structures from inside the buildings, monitoring radioactive contamination, and decontaminating inside the buildings. For the measurement of contamination of suit surfaces of workers, we have developed a hand-held survey meter that can measure and visualize surface radioactive contamination of -nuclides in a high / -ray background environment. In order to selectively measure -nuclides, we designed and built a prototype hand-held survey meter for -rays, which consists of a thin-film ZnS:Ag scintillator, a multi-anode photomultiplier tube (MA-PMT), individual amplification and counting circuits for each channel of the MA-PMT. Based on the result of -ray counting, the developed device is capable of counting the -radiation beyond 2.110 cpm. In the -ray response test, there was no -ray response even when the detector was in close proximity to a high intensity source; The dose rate was estimated to be more than 1 Sv/h. In the future, we plan to reduce the weight and size of the device, as well as improve the usability of the device through actual testing in contaminated environments.

Structural and compositional characteristics of Fukushima release particulate material from Units 1 and 3 elucidates release mechanisms, accident chronology and future decommissioning strategy

Martin, P. G.*; Jones, C. P.*; Bartlett, S.*; Ignatyev, K.*; Megson-Smith, D.*; Satou, Yukihiko; Cipiccia, S.*; Batey, D. J.*; Rau, C.*; Sueki, Keisuke*; et al.

Scientific Reports (Internet), 10, p.22056_1 - 22056_17, 2020/12

https://doi.org/10.1038/s41598-020-79169-2

Hydraulic tests using borehole PB-V01 in the Horonobe Underground Research Project

Samata, Yoichi; Iwata, Tatsuya*; Ishii, Eiichi

JAEA-Data/Code 2019-008, 19 Pages, 2019/09

JAEA-Data-Code-2019-008.pdf:2.82MB
JAEA-Data-Code-2019-008-appendix(CD-ROM).zip:1.38MB

In Horonobe Underground Research Laboratory Project, hydraulic tests for the excavation damaged zone have been performed in order to characterize the hydrological properties of the zone. In PB-V01 borehole, pore pressure observation started in October 2008, but the pore pressure is currently reduced by about 3 MPa compared to that time. In this report, in order to evaluate the influence that this pore pressure drop has on the permeability of the rock, the results of the in-situ permeability test using the long-term hydraulic pressure monitoring device installed in the same hole are summarized.

Wetting induced oxidation of Pt-based nano catalysts revealed by high energy resolution X-ray absorption spectroscopy

Cui, Y.-T.*; Harada, Yoshihisa*; Niwa, Hideharu*; Hatanaka, Tatsuya*; Nakamura, Naoki*; Ando, Masaki*; Yoshida, Toshihiko*; Ishii, Kenji*; Matsumura, Daiju; Oji, Hiroshi*; et al.

Scientific Reports (Internet), 7(1), p.1482_1 - 1482_8, 2017/05

https://doi.org/10.1038/s41598-017-00639-1

Adsorption behaviors of platinum group metals in simulated high level liquid waste using macroporous (MOTDGA-TOA)/SiO-P silica-based absorbent

Ito, Tatsuya; Kim, S.-Y.*; Xu, Y.*; Hitomi, Keitaro*; Ishii, Keizo*; Nagaishi, Ryuji; Kimura, Takaumi

Separation Science and Technology, 48(17), p.2616 - 2625, 2013/10

https://doi.org/10.1080/01496395.2013.807290

As fundamental research for separation of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO-P adsorbent was prepared by impregnation of N,N'-dimethyl-N,N'-di-noctyl-thiodiglycolamide (MOTDGA) and Tri-n-octylamine (TOA) into silica/polymer composite support (SiO-P). The adsorption behavior of Ru(III), Rh(III), and Pd(II) in simulated HLLW onto the adsorbent were investigated by the batch method to obtain their corresponding equilibrium and kinetic data. The adsorbent showed strong adsorption for Pd(II) and the adsorption reached equilibrium within 2 hr. In addition, the use of both MOTDGA and TOA improved adsorption of Ru(III) and Rh(III) better than individual use of them. The adsorptions of Ru(III), Rh(III), and Pd(II) followed the Langmuir adsorption model, and were found to be controlled by the chemisorption mechanism.

Production of no-carrier-added Cu and applications to molecular imaging by PET and PETIS as a biomedical tracer

Watanabe, Shigeki; Iida, Yasuhiko*; Suzui, Nobuo; Katabuchi, Tatsuya*; Ishii, Satomi; Kawachi, Naoki; Hanaoka, Hirofumi*; Watanabe, Satoshi; Matsuhashi, Shimpei; Endo, Keigo*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 280(1), p.199 - 205, 2009/04

https://doi.org/10.1007/s10967-008-7443-9

Detection and measurement of abnormal posture under stressful conditions in nematode

Ide, Kazunori*; Ishikawa, Tomoya*; Arai, Shingo*; Morioka, Tatsuya*; Kaneda, Hiroki*; Suzuki, Michiyo; Sakashita, Tetsuya; Ishii, Naoaki*; Yanase, Sumino*

no journal, , 

Chemical state of cesium in the insoluble radioactive particles emitted from Unit 1 of Fukushima Di-ichi Nuclear Power Station

Satou, Yukihiko; Kobata, Masaaki; Okane, Tetsuo; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Osaka, Masahiko; Owada, Kenji*; Sueki, Keisuke*; Ishii, Tatsuya*

no journal, , 

no abstracts in English

Study on the generation process of radioactive particles emitted from Unit 1 of FDNPP

Ishii, Tatsuya*; Sueki, Keisuke*; Matsuo, Kazuki*; Kurosawa, Masanori*; Satou, Yukihiko; Kobata, Masaaki; Fukuda, Tatsuo; Yoshii, Kenji; Tanida, Hajime; Okane, Tetsuo; et al.

no journal, , 

Radioactive particles were released into the environment by the accident of Fukushima Daiichi Nuclear Power Plant (FDNPP). They have information to understand the inside of the reactor during the accident. Now, nobody knows the generation process of radioactive particles. In this study, we analyzed (1) elements of particles' cross section with SEM-EDS to reveal what is the material and (2) chemical states of elements on particles' surface with HAXPES. (1) Radioactive particles are composed of the two parts. One is the basic material and the other is the heavy elemental materials. We considered the basic material was soda-lime glass and the heavy elemental materials included lead glass. (2) HAXPES brought out that the chemical states of Cs on particles, surface was different in the Na-poor areas and the Na-rich areas. In the Na-poor areas, the chemical state of Cs showed CsFeSiO mainly, but zero valence partly. In the Na-rich areas, the chemical state of Cs couldn't be identified. For above analyses, we can reveal the generation process of radioactive particles.

Extraction properties of acidic diamide-type extractant toward minor actinides and rare earth elements

Nakamura, Satoshi; Suzuki, Hideya*; Ishii, Sho*; Emori, Tatsuya; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Shimojo, Kojiro; Ban, Yasutoshi

no journal, , 

To reduce volume and radiotoxicity of high-level radioactive waste, JAEA has been developing a separation process called "SELECT" (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) for recovering minor actinides (MA) from high-level radioactive liquid-waste. In this study, the applicability of an acidic diamide-type extractant Branched-TetraOctylNitriloAceticAcidDiAmide (B-TONAADA) was investigated with a view to improving the efficiency of MA/Rare Earth Elements (RE) separation in SELECT process. As a results of extraction tests performed with different nitric acid concentrations, specific changes were observed in the lanthanide patterns of distribution ratios, and the distribution ratios of MA were higher than those of RE over a wide range of nitric acid concentrations.