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Sanada, Yukihisa; Oshikiri, Keisuke*; Kanno, Marina*; Abe, Tomohisa
Nuclear Instruments and Methods in Physics Research A, 1062, p.169208_1 - 169208_7, 2024/05
As part of the decommissioning work at the Fukushima Daiichi Nuclear Power Plant (FDNPP), the release of stored treated water began in 2023. In this study, we developed a practical tritium monitor to continuously monitor the concentration of tritiated water, as confirmed by batch sampling measurements at the FDNPP. The monitor is arranged with a flow cell detector comprising inexpensive plastic scintillator pellets and incorporating simultaneous measurements by three detectors, a veto detector, and lead shielding to reduce the influence of environmental 
-rays. The system reached a detection limit of 911 Bq L-1 with a measurement time of 30 min, which is lower than the discharge standard for tritiated water of 1,500 Bq L-1. The system can also qualitatively distinguish the presence of disturbances due to interfering radionuclides other than tritium or background radiation using the 
-ray spectrum.
Koizumi, Mitsuo; Mochimaru, Takanori*; Hironaka, Kota; Takahashi, Tone; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*
Nuclear Instruments and Methods in Physics Research A, 1042, p.167424_1 - 167424_6, 2022/11
Times Cited Count：2 Percentile：50.96(Instruments & Instrumentation)no abstracts in English
Koizumi, Mitsuo; Takahashi, Tone; Hironaka, Kota; Mochimaru, Takanori*; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*
Annual Report of Cooperative Researches at Kindai University Reactor, 2020, p.76 - 80, 2021/12
no abstracts in English
-ray spectroscopic methodsFurutaka, Kazuyoshi
JNC TN8400 2000-028, 70 Pages, 2000/10
JNC-TN8400-2000-028.pdf:1.71MB
This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into two parts: improvements in accuracy in determination of thermal neutron capture cross sections, and improvements in accuracy of photo-nuclear absorption cross section measurements using the HHS. (1)In the measurements of thermal neutron capture cross sections using an activation method, accuracies of the final results attained are limited by (1) accuracy of -ray peak detection efficiencies, and (2) accuracies of -ray emission probabilities. In this study; to determine thermal neutron capture cross sections more accurately, the following researches have been done using a newly developed three-dimensional coincidence measurement system: (1)accurate determination of -ray standard sources using a - coincidence method, for precise calibration of -ray peak detection efficiency, and (2) development of a - coincidence measurement system using a plastic scintillation detector as a -ray detector, for the determination of -ray emission probabilities of short-lived nuclides, and measurement of -ray emission probabilities of 
Tc nuclide using the coincidence system. (2)To transform radioactive nuclides with small thermal neutron capture cross sections, use of photonuclear absorption reaction has been suggested. In order to transform these nuclides efficiently using the reaction, one has to know detailed behavior of the photo-absorption cross sections. In this study, a Monte-Carlo simulation code has been used to create a standard set of -ray response functions of the high-resolution high-energy spectrometer (HHS), to enable reliable analyses of the data obtained by the spectrometer.
Aoyama, Takafumi;
PNC TN9420 96-058, 27 Pages, 1996/10
This report introduces the nuclear instrumentation system and the major radiation measurement techniques used in the Experimental Fast Reactor "JOYO". In the introduction of the nuclear instrumentation system, system function and role as reactor plant equipment, specifications and characteristics of neutron detectors, and layout of the system are described. Reactor dosimetry was used to evaluate neutron dose and their spectra for various irradiation tests and surveilance tests performed in JOYO. The multiple-foil activation method which is currently used and the Helium Accumulation fluence Monitor (HAFM) under development are described. The fuel failure detection (FFD) and the failed fuel detection and location (FFDL) systems in which radiation measurement plays a key role are introduced. It was shown some of the major experimental results obtained from a series of fuel failure simulation tests performed in JOYO. Finally, as a new radiation measurement technique, the Plastic Scintillation Fiber (PSF) is described which is a position sensitive radiation detector that can detect the radiation dose rate at the relevant position in the fiber. The PSF is used to upgrade the gamma-ray distribution measurement to accurately evaluate the Corrosion Products (CPs) behavior in the JOYO primary coolant system.
Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo; *
Proc. of the 4th European Particle Accelerator Conf., Vol. 1; EPAC94, 0, p.548 - 550, 1994/00
no abstracts in English
radiation using a thick plastic scintillatorHoshi, Katsuya; Uchida, Masahiro; Tsujimura, Norio; Momose, Takumaro
no journal, ,
no abstracts in English
Takahashi, Tone; Koizumi, Mitsuo; Hironaka, Kota; Kimura, Yoshiki; Mochimaru, Takanori*; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*
no journal, ,
no abstracts in English
Mochimaru, Takanori*; Takahashi, Tone; Koizumi, Mitsuo; Hironaka, Kota; Kato, Keigo*; Yamanishi, Hirokuni*; Wakabayashi, Genichiro*
no journal, ,
no abstracts in English
