Neutron scattering study of antiferromagnet UPtAl

Ota, Kyugo*; Matsumoto, Yuji*; Watabe, Yuki*; Kaneko, Koji; Tabata, Chihiro; Haga, Yoshinori

New Physics; Sae Mulli, 73(12), p.1170 - 1173, 2023/12

https://doi.org/10.3938/NPSM.73.1170

We have performed the neutron scattering study of antiferromagnet UPtAl with the honeycomb lattice to determine the magnetic structure. UPtAl exhibits two phase transitions at = 9 K and = 26 K. In phase I at , the magnetic reflections described by a propagation vector = (1/3, 0, 0) were observed. In phase II at , magnetic reflections of = (1/3, 0, 0) and = (1/2, 0, 0) were observed and the magnetic reflection intensity of = (1/3, 0, 0) is weak but finite. The hysteresis in the temperature dependent intensities is observed across the phase transition at , suggesting that the transition at is of first order.

Basic study on tritium monitor using plastic scintillator for treated water discharge at Fukushima Daiichi Nuclear Power Plant

Sanada, Yukihisa; Abe, Tomohisa; Sasaki, Miyuki; Kanno, Marina*; Yamada, Tsutomu*; Nakasone, Takamasa*; Miyazaki, Nobuyuki*; Oshikiri, Keisuke*; Watabe, Hiroshi*

Journal of Nuclear Science and Technology, 10 Pages, 2023/00

https://doi.org/10.1080/00223131.2023.2258880

The "treated water" from which the main radioactive materials were removed contains tritium, and stakeholders in Japan have been debating how to treat it. The amount of treated water stored in the facility has reached its limit, and the Japanese government has decided that the treatment method will be to discharge the water into the ocean by FY 2023 (FY: Fiscal Year). The present research developed a simple and practical tritium monitor for the Fukushima Daiichi Nuclear Power Station (FDNPS) tritiated water release. A simple and practical tritium monitor was developed for FDNPS tritiated water release based on thin plastic scintillator sheets. The developed devices were calibrated using standard tritium solutions and a method for calculating the minimum detectable activity. Fifteen 0.25 mm-thick scintillators can be placed in the 0.26 L flow cell where the sample water is fed, yielding an active surface area of 3,200 mm. The efficiency of tritiated water with full water is 0.000035 cps Bq. The minimum detectable activity under simple shielding conditions was 7,800 Bq L (Measurement time was 3,600 s).

Establishment of a novel detection system for measuring primary knock-on atoms

Tsai, P.-E.; Iwamoto, Yosuke; Hagiwara, Masayuki*; Sato, Tatsuhiko; Ogawa, Tatsuhiko; Satoh, Daiki; Abe, Shinichiro; Ito, Masatoshi*; Watabe, Hiroshi*

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11

https://doi.org/10.1109/NSSMIC.2017.8532975

The energy spectra of primary knock-on atoms (PKAs) are essential for radiation damage assessment in design of accelerator facilities. However up to date the experimental data are still limited, due to the poor mass resolution and the high measurement threshold energies in the conventional setup of nuclear physics experiments using solid state detectors, which are typically above a few MeV/nucleon. In this study, a novel detection system consisting of two time detectors and one dE-E energy detector is proposed and being constructed to measure the PKA spectra. The system and detector design was based on Monte Carlo simulations by using the PHITS code. The PHITS simulations show that the system is able to distinguish the PKA isotopes above 0.2-0.3 MeV/nucleon for A=2030 amu; the PKA mass identification thresholds decrease to 0.1 MeV/nucleon for PKAs lighter than 20 amu. The detection system will be tested in the summer of 2017, and the test results will be presented at the conference.

The Technological study on the decommissioning of nuclear facility, etc. in the Tokai Research Establishment

Tomii, Hiroyuki; Matsuo, Kiyoshi*; Shiraishi, Kunio; Kato, Rokuro; Watabe, Kozo; Higashiyama, Yutaka; Nagane, Satoru*; Hanawa, Yukimitsu*

JAERI-Tech 2005-017, 65 Pages, 2005/03

JAERI-Tech-2005-017.pdf:3.79MB

no abstracts in English

Cost estimation method for decommissioning of nuclear facilities

Tomii, Hiroyuki*; Matsuo, Kiyoshi*; Shiraishi, Kunio*; Watabe, Kozo*; Saiki, Hideo; Kawatsuma, Shinji; Rindo, Hiroshi; Zaitsu, Tomohisa

Dekomisshoningu Giho, (31), p.11 - 20, 2005/03

Japanese Government decided that Japan Atomic Energy Research Institute ( JAERI ) and Japan Nuclear Cycle Development Institute ( JNC ) shall be consolidated to a New rganization as of October 2005, which organization would be an Institute for comprehensive research and development for atomic.Through the preparation for unification, JAERI and JNC have been developing the Decommissioning program for own facilities, estimating decommissioning cost and the amount of waste from the decommissioning, and developing Management Program. Planning the Decommissioning program, it is important to estimate decommissioning cost effectively, because JAERI and JNC retain about 230 nuclear facilities which are reactors, fuel cycle facilities and research facilities. Then the decommissioning cost estimation method has developed based on several dismantling and replacement experiences. This method has adopted more estimation fomulae for decommissioning various works than ever, so as to be more reliable. And decommissioning cost for the facilities has estimated under the common condition. This method would be improved, reflecting future nuclear facilities dismantling and replacement events.This paper shows the cost estimation method for nuclear facilities and cost evaluation result for about 230 facilities of both JAERI and JNC.

Development of a positron-emitting Cs tracer for visualizing a radiocesium dynamics in plants and animals

Suzui, Nobuo*; Shibata, Takuya; Yin, Y.-G.*; Funaki, Yoshihito*; Kurita, Keisuke; Hoshina, Hiroyuki*; Yamaguchi, Mitsutaka*; Fujimaki, Shu*; Seko, Noriaki*; Watabe, Hiroshi*; et al.

no journal, , 

no abstracts in English