Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Takashima, Hideki; Takasaki, Koji; Shimizu, Takehiko; Kurihara, Ryoichi
Genshiryoku eye, 57(5), p.72 - 76, 2011/05
no abstracts in English
Usui, Toshihide; Takashima, Hideki; Iwasa, Atsutoshi; Hamazaki, Masaaki
Proceedings of 3rd Asian and Oceanic Congress on Radiation Protection (AOCRP-3) (CD-ROM), 3 Pages, 2010/05
Np Fission Cross Section at YAYOIOki, Shigeo; Takashima, Hideki; Wakabayashi, Toshio; Yamaguchi, Kenji*; Yamawaki, Michio*
JNC TY9400 2004-005, 36 Pages, 2004/05
JNC-TY9400-2004-005.pdf:1.01MB
In the framework of the study on transmutation of minor actinide (MA) nuclides with fast reactors, the fission cross section ratio of 237Np relative to 235U has been measured by using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. The compact BTB fission chamber was prepared for the measurements in the experimental holes called Glory hole and Grazing hole passing though the core center and the side blanket of YAYOI, respectively. Dependence of fission cross section ratios on neutron spectrum was investigated by changing the measurement position in these experimental holes.The measured values of fission cross section ratios were compared with those calculated with the following nuclear data libraries: JENDL-3.2, ENDF/B-VI, JEF-2.2, and JENDL-2. It was found that the calculated values in the center of the core systematically overestimated the measurements by about 30%. Dispersion of the calculated values among the nuclear data libraries was smaller than the above difference from the measured value. We also see the dependence of C/E value on the measurement position. It is hardly said that uncertainty of nuclear data brings about the above overestimation of 30%.The present result remained some issues in terms of the measurement accuracy. If we can get rid of those causes, for example, by means of the unfolding technique on pulse height distribution, the result could be utilized as expletive information in nuclear data validation not only for 237Np, but also for 235U and 238U which characterize the neutron spectrum.
Usui, Toshihide; Iwai, Ryo; Gomibuchi, Masaru; Nakayama, Naoto; Iwasa, Atsutoshi; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
Nakayama, Naoto; Iwasa, Atsutoshi; Hamazaki, Masaaki; Sumiya, Yoshinobu*; Ogiya, Takashi; Irokawa, Hiroyuki; Kano, Yutaka; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
Iwasa, Atsutoshi; Nakayama, Naoto; Maeda, Eita; Usui, Toshihide; Kano, Yutaka; Takashima, Hideki; Irokawa, Hiroyuki
no journal, ,
no abstracts in English
Sakuma, Shuhei; Watanabe, Yuki; Kuroe, Ayame; Takimoto, Misaki; Takashima, Hideki; Takada, Chie; Tsujimura, Norio
no journal, ,
no abstracts in English
-ray spectrometerSaito, Kei; Takashima, Hideki; Emori, Shuichi; Soma, Susumu; Takada, Chie
no journal, ,
no abstracts in English
Irokawa, Hiroyuki; Hamazaki, Masaaki; Ishida, Keiichi; Miura, Yoshiyuki; Iwasa, Atsutoshi; Kano, Yutaka; Mikami, Satoshi; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
Okawa, Yasuhisa; Mikami, Satoshi; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
Takashima, Hideki; Iwasa, Atsutoshi; Eguchi, Kazutoshi; Yoshimochi, Hiroshi; Obayashi, Hiroshi; Emori, Shuichi
no journal, ,
In Alpha- Facility (AGF),Japan Atomic Energy Agency Oarai, the situation of the existing nuclide composition ratio etc. has changed greatly by manufacturing of the Am content mixed oxide fuel and executing the characteristic test. Therefore, the nuclide composition ratio etc. concerned were measuring analyzed, and the radiation management method in the emergency was examined as a result. As for the analysis sample, it gathered in the cell and the glove box (17 places) in facility, and the nuclide composition ratio was evaluated from the measurement result of the mass spectrometry etc. As a result, the nuclide composition approximated to the MA fuel pellet was seen of many sample and the difference was seen in the nuclide composition of each sample (especially, Am-241, Pu-239, and Pu-240). The result of the radiation management method in the emergency becomes as follows from these. (1) It is possible to execute immediately the initial assessment of internal expose from these data obtained this time and all alpha radioactivity that can be measured comparatively promptly by the presumption evaluation of radioactivities of each nuclides such as Pu and Am on the accident generation place. (2) If happened an abnormal discharge and the air contamination etc. of A radioactive substance, the originating place and the nuclide composition can be presumed by evaluating the radioactivity of Am-241 and all alpha radioactivity that can be measured comparatively promptly.
-to-
ratio and the result of nuclide analysisNakayama, Naoto; Usui, Toshihide; Gomibuchi, Masaru; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
-ray dust monitorSasaki, Kazuki; Sagawa, Naoki; Hosomi, Kenji; Takashima, Hideki
no journal, ,
no abstracts in English
Imahashi, Atsushi; Sagawa, Naoki; Kanazawa, Nobuyuki*; Tamura, Toshinobu*; Hosomi, Kenji; Takashima, Hideki
no journal, ,
Alpha dust monitors are used for continuous measurering of airborne alpha contamination in radiation control area in NCL JAEA. In case of emergency, alarm is issued to evacuate workers. However, number of false alarms due to degradation of equipment are increasing year by year, because the equipment has been used more than 30 years. Now, we are updating our old silicon detectors to new ion-implanted silicon detectors with high endurance. We are also installing new preamplifier cercuits which is strong against electrical noise. As a result, reliability of alpha dust monitors has been ensured. In this talk, a report about our effective deal with the aging equipment will be given.
Hashimoto, Suki*; Sakuma, Shuhei; Hosomi, Kenji; Watanabe, Yuki; Unno, Motoyoshi; Takashima, Hideki
no journal, ,
The standards for passive neutron personal dosimeters do not cover high-dose exposures such as criticality accidents, so the upper limit of the dose for personal neutron dosimeters is 20 mSv. On the other hand, the upper limit of dose during emergency work was raised to 250 mSv during the TEPCO Fukushima Daiichi Nuclear Power Plant accident caused by the Great East Japan Earthquake, so it is desirable that personal neutron dosimeters be able to support the upper limit of 250 mSv. In this study, we confirmed the availability of neutron dose evaluation of 250 mSv by irradiating neutron personal dosimeter using PADC detector called CR-39 with up to 300 mSv.
Usui, Toshihide; Takashima, Hideki; Saito, Kei; Tagawa, Hiroshi; Ito, Kimio; Emori, Shuichi
no journal, ,
no abstracts in English
Iwasa, Atsutoshi; Nakayama, Naoto; Mikami, Satoshi; Eguchi, Kazutoshi; Takashima, Hideki; Hitomi, Junichi; Gomibuchi, Masaru*
no journal, ,
no abstracts in English
Ishida, Keiichi; Mikami, Satoshi; Iwasa, Atsutoshi; Hamazaki, Masaaki; Usui, Toshihide; Takashima, Hideki; Hitomi, Junichi
no journal, ,
no abstracts in English
