Decontamination simulation and future prediction of air dose rate in difficult to return zone in Fukushima Prefecture

Yamashita, Takuya; Sawada, Noriyoshi*

JAEA-Research 2019-010, 227 Pages, 2020/03

JAEA-Research-2019-010.pdf:21.44MB
JAEA-Research-2019-010(errata).pdf:0.5MB

In order to support the decontamination activities proceeded by the national government and municipalities in terms of technology, we have developed a simulation system "RESET" which predicts the effect of decontamination. We also developed a "two-component model" for the purpose of predicting long-term changes in the air dose rate. We use these tools to perform decontamination simulation and predictive analysis of the air dose rate after decontamination, and provide information to the national government and municipalities aiming for reconstruction. In this report, the verification result of the prediction methods implemented using actual measurement data obtained in the "Decontamination model demonstration project in difficult-to-return zone" and "Survey result on transition of air dose rate after decontamination model demonstration project" conducted by Ministry of the Environment. In addition, the decontamination simulation conducted for the entire difficult-to-return area and the results of future prediction of the air dose rate after decontamination are shown.

Photoelectron diffraction from laser-aligned molecules with X-ray free-electron laser pulses

Nakajima, Kyo*; Teramoto, Takahiro*; Akagi, Hiroshi; Fujikawa, Takashi*; Majima, Takuya*; Minemoto, Shinichiro*; Ogawa, Kanade*; Sakai, Hirofumi*; Togashi, Tadashi*; Tono, Kensuke*; et al.

Scientific Reports (Internet), 5, p.14065_1 - 14065_11, 2015/09

https://doi.org/10.1038/srep14065

We report on the measurement of deep inner-shell 2p X-ray photoelectron diffraction (XPD) patterns from laser-aligned I molecules using X-ray free-electron laser (XFEL) pulses. The XPD patterns of the I molecules, aligned parallel to the polarization vector of the XFEL, were well matched with our theoretical calculations. Further, we propose a criterion for applying our molecular-structure-determination methodology to the experimental XPD data. In turn, we have demonstrated that this approach is a significant step toward the time-resolved imaging of molecular structures.

Control of coordination and luminescence properties of lanthanide complexes using octadentate oligopyridine-amine ligands

Wada, Atsushi*; Watanabe, Masayuki; Yamanoi, Yoshinori*; Nankawa, Takuya; Namiki, Kosuke*; Yamasaki, Mikio*; Murata, Masaki*; Nishihara, Hiroshi*

Bulletin of the Chemical Society of Japan, 80(2), p.335 - 345, 2007/02

https://doi.org/10.1246/bcsj.80.335

Lanthanide complexes with linear and cyclic octadentate oligopyridine-amine ligands were synthesized, and their molecular structures were determined by single-crystal X-ray crystallography. All of the complexes had a distorted capped square antiprism (CSAP) geometry, and the coordination environments of lanthanide complexes were more distortedfor the complexes with the linear ligand than those with the cyclic ligand. The Eu complexes with the linear ligand showed more intense emissions, which were attributed to the D F transition, than the complex withthe cyclic ligand in acetonitrile, which can be attributed to the distortion in the coordination environments. These results indicate that the coordination environments of lanthanide complexes, and thus the luminescence properties, can be controlled by tuning the geometrical structures of polydentate ligands.

Chemical studies of Mo and W in preparation of a Seaborgium (Sg) reduction experiment using MDG, FEC, and SISAK

Toyoshima, Atsushi; Miyashita, Sunao*; Asai, Masato; Sato, Tetsuya; Kaneya, Yusuke; Tsukada, Kazuaki; Kitatsuji, Yoshihiro; Nagame, Yuichiro; Schdel, M.; Lerum, H. V.*; et al.

no journal, , 

To carry out a continuous reduction experiment of Sg with the low production rates and the short half-life, we are developing a new chemistry assembly consisting of a membrane degasser (MDG), a flow electrolytic column (FEC), the continuous liquid-liquid extraction apparatus, and the liquid scintillation counting system (SISAK). Recently, we have begun preparatory studies with Mo and W isotopes. Aqueous solution dissolving Mo and W was successfully separated from a carrier gas. Redox couples of Mo(VI)/Mo(V) and W(VI)/W(V) in HCl have been characterized for their macro amounts. Extraction behavior of Mo(VI) and W(VI) between toluene containing hinokitiol (HT) and HCl was successfully observed by a batch method. On-line extractions of short-lived Mo and W were also carried out using SISAK and MDG. In the symposium, our present status of the preparation with Mo and W will be presented.

Turbomolecular pump for achieving ultra-high vacuum in a high-power proton accelerator vacuum system

Kamiya, Junichiro; Kinsho, Michikazu; Ogiwara, Norio*; Sakurai, Mitsuru*; Mabuchi, Takuya*; Wada, Kaoru*

no journal, , 

Challenges for ultrahigh vacuum (UHV) region in J-PARC 3 GeV rapid cycling synchrotron (RCS) come from the large static and dynamic outgassing. In the RCS vacuum system, turbomolecular pumps (TMP) have been used as main pump because it can evacuate such continuous and additional outgassing with a large pumping speed in the wide pressure range. The operation of the RCS vacuum system showed that the UHV was rapidly obtained from the atmospheric pressure. It was also shown that the large additional outgassing during the high-power beam operation was promptly evacuated by the TMP. The future operation with more high-beam power requires the vacuum system for the lower pressure region. We have developed a TMP with the rotor of titanium alloy with high mechanical strength. We report the advantages of the TMP in the high-power beam accelerators and the development of the TMP with titanium alloy.