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Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Taguchi, Mitsumasa*; Seito, Hajime*; Inoue, Hiroyuki*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*
Isotope News, (782), p.40 - 44, 2022/08
The stagnant water in the reactor building at Fukushima Daiichi Nuclear Power Station (1F) is exposed to the radiation from fuel debris and radioactive species. This water contains much amounts of impurities from the seawater which was injected in the emergency cooling. The impurities will affect the radiolysis and corrosive conditions in the water under irradiation. So, the water radiolysis data, corrosion data of steels under irradiations, and the evaluated potential impacts of corrosion in the decommissioning process of 1F are arranged as the database for corrosion under irradiation. This paper introduces the outline of this database.
Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Ueno, Fumiyoshi; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; et al.
JAEA-Review 2021-001, 123 Pages, 2021/06
JAEA-Review-2021-001.pdf:10.33MB
In the implement of the decommissioning of Fukushima Daiichi Nuclear Power Station (1F), there are many problems to be solved. Specially, the mitigation of the aging degradation by the corrosion of the structural materials is important to implement the decommissioning safely and continuously. However, there are limited data for the environmental factors of corrosion in 1F, and the condition of 1F is continuously changing. So, the literature data for the water radiolysis and the corrosion under irradiation are listed as the database of corrosion under irradiation in this report. And the new obtained radiolysis and corrosion data, which have not been reported in the literature and will be required in the decommissioning of 1F, are reported.
Omori, Atsushi*; Akiyama, Eiji*; Abe, Hiroshi*; Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; et al.
Zairyo To Kankyo, 69(4), p.107 - 111, 2020/04
To evaluate the effect of oxidants, which are formed by radiolysis of water under gamma ray irradiation, on the corrosion of a carbon steel in humid environment, ozone was introduced as a model oxidant in to humidity-controlled air at 50
C in a thermo-hygrostat chamber. Corrosion monitoring was performed by using an Atmospheric Corrosion Monitor-type (ACM) sensor consisting of a carbon steel anode and an Ag cathode. The output current of the ACM sensor was increased with the increase in relative humidity and it was obviously increased with the increase in the introduced ozone concentration at each relative humidity. The results indicate that ozone accelerates the corrosion of the carbon steel. The effect of ozone on the corrosion acceleration is attributed to the fast reduction reaction and fast dissolution reaction in to water compared to that of oxygen.
Co 
-ray irradiation facilitiesUno, Sadanori; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Yamasaki, Shota; Agematsu, Takashi; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 172, 2016/02
This paper reports on the operation status of the -ray irradiation facilities and the electron accelerator in fiscal 2014 at the Takasaki Advanced Radiation Research Institute of JAEA. The -ray irradiation facilities were operated smoothly, whereas the electron accelerator stopped for five months because of successive troubles of discharge due to deterioration of equipment over thirty-four years. The annual operation times of the -ray irradiation facilities of the first, second and food buildings were 19,907, 13,831 and 7,293 hours, respectively, and that of the electron accelerator was 746 hours. The -ray irradiation facilities were replenished with new five sources of 2.22 PBq, and twenty old sources were removed for disposal. The electron accelerator was repaired for each trouble, however, the complete recovery has not yet been achieved.
-ray irradiation induced radicals in binder materials of alanine dosimeter componentsSeito, Hajime; Saiki, Seiichi; Kobinata, Kishio*; Kojimja, Takuji*
JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 147, 2016/02
-ray irradiation facilitiesAgematsu, Takashi; Uno, Sadanori; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Yamasaki, Shota; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 173, 2016/02
The electron accelerator and the three -ray irradiation facilities of Takasaki Advanced Radiation Research Institute were operated for various research subjects according to the operation plan in FY 2014. The number of research subjects in FY 2014 decreased at the electron accelerator with operation stop by accelerator trouble, and increased slightly at the -ray irradiation facilities as compared with FY 2013, and research subjects were 205 and 857, respectively. Among these research subjects, 35 and 172 related to recovery from the Fukushima Daiichi Nuclear disaster, respectively, were performed at the electron accelerator and the -ray irradiation facilities, respectively.
Uno, Sadanori; Hanaya, Hiroaki; Yamasaki, Shota; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Agematsu, Takashi; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.
Dai-28-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.121 - 123, 2015/12
no abstracts in English
-ray irradiation facilitiesAgematsu, Takashi; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 183, 2015/03
The electron accelerator and the three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2013. The number of research subjects at the electron accelerator and at the -ray irradiation facilities kept constant from FY 2012. Among these research subjects, 47 and 91 ones respectively performed at the electron accelerator and the -ray irradiation facilities were relevant to recovery from the Fukushima Daiichi nuclear disaster.
-ray irradiation facilitiesAgematsu, Takashi; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Kawashima, Ikuo*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 182, 2015/03
The electron accelerator and the -ray irradiation facility have been operated approximately smoothly. The annual operation time in FY 2013 for the electron accelerator, the first, the second cobalt irradiation facility and food irradiation facility are 1242 h, 18,900 h, 11,804 h and 6,587 h, respectively. Typically repairs were next ones. The SF
gas withdrawal system was renewed at the electron accelerator. The 600 m
water storage tank was installed to keep pool-water for the cobalt facilities maintenance. New pieces of Co sources were purchased and loaded to the first and the second irradiation facility. The maintenance check was done for the food irradiation facility.
-ray irradiation facilitiesAgematsu, Takashi; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 181, 2014/03
The electron accelerator and the three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2012. The number of research subjects at the electron accelerator kept constant compared with FY 2011. The number of research subjects at the -ray irradiation facilities slightly decreased year after year. Of all these research subjects, 14 ones at the electron accelerator and 93 ones at the -ray irradiation facilities were relevant to the Fukushima Daiichi nuclear disaster.
-ray irradiation facilitiesAgematsu, Takashi; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 180, 2014/03
The electron accelerator and the -ray irradiation facility have been operated without serious trouble. The annual operation time in FY 2012 for the electron accelerator, the first, the second cobalt irradiation facility and food irradiation facility are 910 h, 15,738 h, 10,537 h and 7,871 h, respectively. Typicaly repairs were next ones. The SF6 gas withdrawal system broke of the accelerator, and there was trouble of mixing in of air. The maintenance check of the first irradiation facility was done. The Co ources were purchased and loaded to the first irradiation facility. Fifteen pencil sources of Co with length of 30 cm each, twelve ball sources of Co and five 
Cs source were disposed of, and they were transferred to Japan Radioisotope Association (JRIA).
Hiroki, Akihiro; Sato, Yuichi*; Nagasawa, Naotsugu; Ota, Akio*; Seito, Hajime; Yamabayashi, Hisamichi*; Yamamoto, Takayoshi*; Taguchi, Mitsumasa; Tamada, Masao; Kojima, Takuji
Physics in Medicine & Biology, 58(20), p.7131 - 7141, 2013/10
Times Cited Count：18 Percentile：56.24(Engineering, Biomedical)-ray irradiation facilitiesHaruyama, Yasuyuki; Agematsu, Takashi; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 175, 2013/01
The electron accelerator and the three -ray irradiation facilities were operated for various research subjects according to the operation plan in FY 2011 without serious trouble. The number of research subjects at the electron accelerator increased in the research fields of nuclear facilities and resources & biotechnology, and decreased in the fields of material processing and material for space. The number of research subjects at the -ray irradiation facilities increased in the fields of material for space and material processing, and decreased in the fields of nuclear facilities and resources & biotechnology. Of all these research subjects, 15 ones at the electron accelerator and 94 ones at the -ray irradiation facilities were relevant to the Fukushima Daiichi nuclear disaster.
-ray irradiation facilitiesAgematsu, Takashi; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; et al.
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 174, 2013/01
The electron accelerator and the -ray irradiation facility have been operated without serious trouble. The annual operation time in FY 2011 for the electron accelerator, the first, the second cobalt irradiation facility and food irradiation facility are 1,059 h, 18,722 h, 9,976 h and 7,427 h, respectively. Typically repairs were next ones. The beam control circuit trouble and the isolation trouble by mixing in of air into SF gas at electron accelerator were repaired. The maintenance check of the second irradiation facility was done. The Co sources were purchased and loaded to the second irradiation facility. Forty five pencil sources of Co with length of 30 cm each, eight coin sources of Co and the -ray radiographic apparatus with a Co source were disposed to Japan Radioisotope Association (JRIA).
Seito, Hajime; Nagao, Yuto; Momoki, Yohei*; Kaneko, Hirohisa; Nakagawa, Kazumichi*; Kojima, Takuji
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 153, 2013/01
no abstracts in English
Nagao, Yuto; Seito, Hajime; Momoki, Yohei*; Kaneko, Hirohisa; Nakagawa, Kazumichi*; Kojima, Takuji
Radioisotopes, 61(4), p.173 - 177, 2012/04
Applications of alanine dosimeter are widen to dosimetry in space environment and so on. The effect of temperature during and after irradiation between 20C and 80C on the dose response of alanine dosimeters was investigated under low dose of about 10 - 20 Gy and long time of about 100 hours irradiations. When a stable component of the dose response under high irradiation temperature is estimated on the basis of the effect of storage temperature after irradiation taking into account the known irradiation temperature coefficient, dose evaluation using alanine dosimeter should be more accurate even suffering from combined temperature effects during and after irradiation.
Seito, Hajime; Hakoda, Teruyuki; Hanaya, Hiroaki; Haruyama, Yasuyuki; Kaneko, Hirohisa; Yamashita, Takashi*; Kojima, Takuji
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 150, 2012/01
no abstracts in English
-ray irradiation facilities and electron acceleratorKaneko, Hirohisa; Haruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; Kawashima, Ikuo*; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 175, 2012/01
Irradiation facilities and an electron accelerator were operated for various research subjects according to the operation plan in FY 2010 without serious trouble. Utilization was stopped until the end of the fiscal year due to inspection etc., after the earthquake occurred on March 11. The number at -ray irradiation facilities increased in the field of environment and basic technology, and decreased in the field of material processing and resource & bio-technology. The number of research subjects at the electron accelerator increased in the research fields of material for space, and decreased in the field of material processing and joint use.
-ray irradiation facilitiesHaruyama, Yasuyuki; Hanaya, Hiroaki; Yamagata, Ryohei; Seito, Hajime; Nagao, Yuto; Kaneko, Hirohisa; Yamaguchi, Toshiyuki*; Yagi, Norihiko*; Takagi, Masahide*; Kawashima, Ikuo*; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 174, 2012/01
The electron accelerator and -ray irradiation facilities have been operated without serious troubles before the earthquake happened in March 11 2011. The electron accelerator and -ray irradiation facilities were stopped with concern about the earthquake damage, for 13 and 20 days, respectively.
Seito, Hajime; Matsui, Shinjiro*; Hakoda, Teruyuki; Ishikawa, Masayoshi*; Haruyama, Yasuyuki; Kaneko, Hirohisa; Kimura, Jun*; Kojima, Takuji
Zairyo Gijutsu, 30(1), p.10 - 16, 2012/01
The dosimetry of a 110 keV electron beam (EB) irradiation field is studied using a calorimeter, film dosimeter, and Monte Carlo simulation. This is important base for dose control in practical processing to guarantee the process reproducibility and product reliability. The simulation results are validated on the measurement of the energy fluence obtained by the calorimeter at one position in the air plane at different distances from a beam exit window. The spatial dose distribution obtained from the simulation is compared to that obtained by the film dosimeter. They show good agreement within 
5.0%. The precision of 5.0% is sufficient to control the surface modification of polymers and the development of semiconductor devices in practical radiation processing. These results suggest that film dosimetry results at just one position in the air plane are sufficient to determine the irradiation characteristics of the low energy EB, and to provide a base of quality control measures in practical radiation processing.
