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Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
Hoshasen (Internet), 47(3), p.89 - 96, 2022/10
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
Nuclear Instruments and Methods in Physics Research A, 1034, p.166793_1 - 166793_6, 2022/07
Times Cited Count：3 Percentile：66.21(Instruments & Instrumentation)Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10
For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and 
Sr/Y radioactive point source, basic properties of source position detection were confirmed.
) reaction at 12, 20, and 30 MeVPatwary, M. K. A*; Kin, Tadahiro*; Aoki, Katsumi*; Yoshinami, Kosuke*; Yamaguchi, Masaya*; Watanabe, Yukinobu*; Tsukada, Kazuaki; Sato, Nozomi*; Asai, Masato; Sato, Tetsuya; et al.
Journal of Nuclear Science and Technology, 58(2), p.252 - 258, 2021/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)While designing deuteron accelerator neutron sources for radioisotopes production, nuclear data for light elements such as Li, Be, and C have been systematically measured in the deuteron energy range from a few MeV to around 50 MeV. Currently, the experimental data available on double-differential thick-target neutron yields (DDTTNYs) is insufficient, especially for deuteron energies between 18 and 33 MeV. In this study, we measured the DDTTNYs of () reactions on 
C target for incident deuteron energies of 12, 20, and 30 MeV using the multiple-foils activation method to improve nuclear data insufficiency. We applied the GRAVEL code for the unfolding process to derive the DDTTNYs. The results were compared with the calculation by DEURACS. The present data were also used to confirm the systematics of the differential neutron yields at 0
and total neutron yield per incident deuteron in the wide range of deuteron energy.
*; Kitada, Takanori*; Tagawa, Akihiro; *; Takeda, Toshikazu*
JNC TJ9400 2000-006, 272 Pages, 2000/02
JNC-TJ9400-2000-006.pdf:9.69MB
Investigation was made on the follwing three themes as a part of the improvement of reactor physics analysis method for FBR with various core concept. Part 1: Investigation of Error Estimation of Neutron Spectra in FBR and Suggestions to Improve the Accuracy. In order to improve the spectrum unfolding method used in fast experimental reactor JOYO, a trial was made to evaluate the error in the estimated neutron spectrum, cause by cause. And the evaluated errors were summed up to obtain the most probable and reasonable error as possible. The summed up error was found relatively small compared to the error caused by the uncertainty of cross section data: most of the error in the spectrum unfolding method can be attributed to the error in cross sections. It was also found that the error due to the fission spectrum causes a considerable error in the high energy neutron spectrum which is over several MeV. Part 2: Study on Reactor Physics Analysis Method for Gas-Cooled FBR. In gas-cooled FBR, the portion of coolant channels in core volume is larger than sodium-cooled FBR. This leads to strong neutron streaming effects. For sodium-cooled FBR, several methods were proposed to evaluate the neutron streaming effect, however, these methods can not be used directly to gas-cooled reactor because the direction dependent diffusion coefficient becomes infinitive along the direction pararel to the coolant chammel. In this study, a new method is proposed to evaluate the neutron streaming effect, based on the method taking the axial buckling into consideration, which method was originally proposed by K
hler. Part 3: Study on Reactor Physics Analysis Method for Water-Cooled FBR An investigation was made on low-moderated water-cooled FBR, on the point that the ordinary used analysis method for FBR may give considerable difference in results in such core. In light water reactors, it is well known that the space dependence of self-shielding effect of heavy nuclides are considerably ...
Cf and 
Am-Be neutron sourceJ.R.Dumais*; Yoshizawa, Michio; Yamaguchi, Yasuhiro
JAERI-Tech 98-005, 65 Pages, 1998/03
no abstracts in English
Takahashi, Fumiaki; ; Yamaguchi, Yasuhiro
JAERI-Tech 97-006, 36 Pages, 1997/03
no abstracts in English
Sumino, Kozo; Aoyama, Takafumi; Emoto, Takehiko
PNC TN9410 96-233, 27 Pages, 1996/08
It is important to accurately evaluate Corrosion Products (CPs) behavior in a FBR plant to reduce the personnel exposure due to CP deposition. A series of measurements of the gamma-ray dose rate distribution has been carried out in the Experimental Fast Reactor JOYO to characterize the CP behavior in the primary coolant system. The Plastic Scintillation Fiber (PSF), which is a position sensitive radiation detector that can detect the radiation dose rate at the relevant position in the fiber, was introduced to upgrade the gamma-ray distribution measurement in JOYO. In order to apply the PSF for the JOYO environment, the specification of the fiber was modified to obtain a wide range of sensitivity from about 0.01mSv/h up to 10mSv/h. This range covers the gamma-ray dose rate in the JOYO primary coolant system. In higher gradients of dose rate distribution than that of the PSF's position resolution, the measured data were unfolded by using the response matrix with a successive approximation method to reproduce the narrow distribution. As a result of the study on PSF, the continuous gamma-ray dose rate distribution was able to be measured by PSF in a few minutes, whereas point data at 1 m intervals were laboriously obtained by a set of Thermo-luminescence Dosimeters (TLDs). It was confirmed that the measurement of CP behavior upgraded significantly by using a detailed gamma-ray dose rate distribution.
Sakamoto, Yukio; Tanaka, Susumu; ; Nakane, Yoshihiro; Meigo, Shinichiro; Takada, Hiroshi; Tanaka, Shunichi; Takada, M.*; Kurosawa, Tadahiro*; Nakamura, Takashi*; et al.
Genshikaku Kenkyu, 41(3), p.95 - 99, 1996/06
no abstracts in English
Takahashi, Fumiaki;
IRPA9: 1996 International Congress on Radiation Protection, Proceedings, 4, p.215 - 217, 1995/00
no abstracts in English
Meigo, Shinichiro; Takada, Hiroshi; Chiba, Satoshi; *; *; *; Maehata, Keisuke*; Shigyo, Nobuhiro*; *; Watanabe, Yukinobu*; et al.
PSI-Proceedings 95-02, Vol. 2, 0, p.442 - 453, 1995/00
no abstracts in English
Tsuda, Shuichi; Tanigaki, Minoru*; Saito, Kimiaki
no journal, ,
A GPS-aided radiation monitoring system KURAMA and the KURAMA-II developed by Kyoto University has been utilized after the Fukushima Dai-ichi Nuclear Power Plant accident in a mapping project of radionuclides deposited in the environment and monitoring of dose rates in air. KURAMA-II has a function of precisely evaluating dose rates in air based on measured pulse-height spectra from the incorporated CsI(Tl) scintillation detector. In this study, to evaluate dose contribution of the radionuclides in the environment, photon energy spectra was estimated by an unfolding method, using the measured pulse-height spectra and the dataset of the calculated response functions of the CsI(Tl) scintillation detector in a simulative environment. The results of dose contributions of artificial and natural radionuclides based on the estimation method will be reported in the session, "Mapping project in Fukushima and related researches".
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Hanai, Tetsuya*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
no journal, ,
For the reduction of the external dose of workers in the process of Fukushima Daiichi Nuclear Power Station (1F) decommissioning and to propose an effective decontamination plan, it is necessary to grasp the distribution of locally existing hotspots. A one-dimensional radiation distribution measurement system applying time-of-flight method to scintillating optical fiber has been widely applied after the 1F accident, but in a high dose rate environment such as 1F reactor building, a pile-up of signal and chance-coincidence effect of a sensor is a problem. Therefore, as an integral-type measurement method that can avoid problems such as pile-up, we propose a reverse-estimation method which measures the wavelength spectrum at the fiber edge and estimates the incident position of radiation to the fiber using the fact that the attenuation length of light depends on the wavelength.
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
no journal, ,
We are developing a one-dimensional radiation distribution sensing method using optical fiber to measure the distribution of hot spots in the Fukushima Daiichi Nuclear Power Station (1F) buildings. As a new radiation distribution sensing technique applicable to high dose rate environments, a wavelength-resolved analysis method was developed. This method measures the emission wavelength spectrum derived from the interaction between the optical fiber and radiation on one side of the fiber and estimates the radiation incident position to the fiber reversely using the fact that the attenuation length of light along the fiber depends on the wavelength. In the presentation, we report the results of the principle verification of this method.
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
no journal, ,
no abstracts in English
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
no journal, ,
no abstracts in English
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
no journal, ,
no abstracts in English
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
no journal, ,
Terasaka, Yuta
no journal, ,
no abstracts in English
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*
no journal, ,
no abstracts in English
