Development of imaging system with ultra-high spatial resolution aiming to detect alpha-dust (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2019-038, 57 Pages, 2020/03

JAEA-Review-2019-038.pdf:4.6MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of Imaging System with Ultra-high Spatial Resolution Aiming to Detect Alpha-dust". In the present study, we have developed a prototype of a system aiming to elucidate the behavior of alpha-dust generated at the time of debris retrieval. In this system, alpha-ray is first converted to visible light by novel scintillator. Then, imaging with ultra-high resolution will be possible using a lens and an Si-semiconductor camera (CMOS camera). Also, it will be possible to identify the species of alpha-ray emitting nuclides by unfolding of the spectra. The demonstration tests of the system will be conducted for dust samplers at the Plutonium Fuel Development Center, JAEA. In the development of the present system, it is important to use scintillator whose emission wavelength is sensitive to the CMOS camera as well as high emission scintillator. Considering these conditions, the key technology will be the improvement of the purity of crystals and optimization of the shapes of the materials including powers.

A Neutron crystallographic analysis of a rubredoxin mutant at 1.6 resolution

Chatake, Toshiyuki*; Kurihara, Kazuo; Tanaka, Ichiro*; Tsyba, I.*; Bau, R.*; Jenney, F. E. Jr.*; Adams, M. W. W.*; Niimura, Nobuo

Acta Crystallographica Section D, 60(8), p.1364 - 1373, 2004/08

https://doi.org/10.1107/S090744490401176X

A neutron diffraction study has been carried out at 1.6 resolution on a mutant rubredoxin from using the BIX-3 single-crystal diffractometer at the JRR-3 reactor of JAERI. In order to study the unusual thermostability of rubredoxin from , the hydrogen-bonding patterns were compared between the native and a 'triple-mutant' variant where three residues were changed so that they are identical to those in a mesophilic rubredoxin. In the present study, some minor changes were found between the wild-type and mutant proteins in the hydrogen-bonding patterns of the Trp3/Tyr3 region. The H/D-exchange ratios in the protein were also studied. The results suggest that the backbone amide bonds near the four Cys residues of the FeS redox center are most resistant to H/D exchange. In addition, the 1.6 resolution of the present neutron structure determination has revealed a more detailed picture than previously available of some portions of the water structure, including ordered and disordered O-D bonds.