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Journal Articles

Evaluation of materials for developing a new individual dosemeter using electron spin resonance spectroscopy

Kitamura, Yoshimasa; Oka, Toshitaka; Seito, Hajime*; Yokozuka, Eri*; Nagasawa, Naotsugu*; Kitatsuji, Yoshihiro

Radiation Protection Dosimetry, 200(16-18), p.1660 - 1665, 2024/11

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

In this work, we evaluated the applicability of hydroxyapatite, which is a main component of tooth enamel, as individual dosimeters that can detect from less than 1 Gy to several tens Gy. Commercially available hydroxyapatite was irradiated by $$^{60}$$Co gamma-ray up to 75 Gy and ESR spectrum of the irradiated sample was observed. The relationship between the intensity of produced carbonated radical and the absorbed dose shows a good linearity ($$mathrm{R}^{2}=1$$) from 0 to 75 Gy. The detection limit of this samples was estimated to be 99.7 mGy, and the radical intensity do not change for eight month from the irradiation. These results suggest that this sample can be used as a candidate of the individual dosimeter.

Journal Articles

ESR measurement of carbonated hydroxyapatite for dosemeter

Seito, Hajime*; Yokozuka, Eri*; Oka, Toshitaka; Kitatsuji, Yoshihiro; Nagasawa, Naotsugu*

Radiation Protection Dosimetry, 200(16-18), p.1656 - 1659, 2024/11

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

We have examined dosimetric characteristics of bio-inspired carbonated hydroxyapatite (CO$$_{3}$$HAp), which is a main component of calcified tissues like tooth enamel. CO$$_{3}$$HAp powder samples were exposed to gamma-ray with radiation doses ranging from 1 Gy to 1000 Gy at room temperature, and ESR spectra were measured immediately after irradiation and subsequently measured each 1 day during 90 days. The post-irradiation fading resulted in significant 20% decay of the signal amplitude, which stabilised within 7 days after irradiation, and the intensity approached a constant. The sample has good linear dose response in the experiment range of 10 Gy - 1000 Gy. Our results indicate that the CO$$_{3}$$HAp materials is suitable for chemical dosimetry.

Journal Articles

Database for corrosion under irradiation

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.

JAEA Reports

Database for corrosion under irradiation conditions (Contract research)

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.

Journal Articles

Corrosion monitoring in humidity-controlled environment simulating gamma ray irradiation

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$$^{circ}$$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.

Journal Articles

ESR dosimetric study on $$gamma$$-ray irradiation induced radicals in binder materials of alanine dosimeter components

Seito, Hajime; Saiki, Seiichi; Kobinata, Kishio*; Kojimja, Takuji*

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 147, 2016/02

Journal Articles

Operation of the electron accelerator and the $$^{60}$$Co $$gamma$$-ray irradiation facilities

Uno, 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 $$gamma$$-ray irradiation facilities and the electron accelerator in fiscal 2014 at the Takasaki Advanced Radiation Research Institute of JAEA. The $$gamma$$-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 $$gamma$$-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 $$gamma$$-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.

Journal Articles

Utilization status of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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 $$gamma$$-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 $$gamma$$-ray irradiation facilities, respectively.

Journal Articles

Current status of the electron accelerator at TARRI, JAEA

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

Journal Articles

Operation of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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$$_{6}$$ gas withdrawal system was renewed at the electron accelerator. The 600 m$$^{3}$$ water storage tank was installed to keep pool-water for the cobalt facilities maintenance. New pieces of $$^{60}$$Co sources were purchased and loaded to the first and the second irradiation facility. The maintenance check was done for the food irradiation facility.

Journal Articles

Utilization status of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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 $$gamma$$-ray irradiation facilities kept constant from FY 2012. Among these research subjects, 47 and 91 ones respectively performed at the electron accelerator and the $$gamma$$-ray irradiation facilities were relevant to recovery from the Fukushima Daiichi nuclear disaster.

Journal Articles

Utilization status of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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 $$gamma$$-ray irradiation facilities slightly decreased year after year. Of all these research subjects, 14 ones at the electron accelerator and 93 ones at the $$gamma$$-ray irradiation facilities were relevant to the Fukushima Daiichi nuclear disaster.

Journal Articles

Operation of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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 $$^{60}$$Co ources were purchased and loaded to the first irradiation facility. Fifteen pencil sources of $$^{60}$$Co with length of 30 cm each, twelve ball sources of $$^{60}$$Co and five $$^{137}$$Cs source were disposed of, and they were transferred to Japan Radioisotope Association (JRIA).

Journal Articles

Preparation of polymer gel dosimeters based on less toxic monomers and gellan gum

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:20 Percentile:58.10(Engineering, Biomedical)

Journal Articles

Operation of the electron accelerator and the $$gamma$$-ray irradiation facilities

Agematsu, 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 $$gamma$$-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$$_{6}$$ gas at electron accelerator were repaired. The maintenance check of the second irradiation facility was done. The $$^{60}$$Co sources were purchased and loaded to the second irradiation facility. Forty five pencil sources of $$^{60}$$Co with length of 30 cm each, eight coin sources of $$^{60}$$Co and the $$gamma$$-ray radiographic apparatus with a $$^{60}$$Co source were disposed to Japan Radioisotope Association (JRIA).

Journal Articles

Utilization of the electron accelerator and the $$gamma$$-ray irradiation facilities

Haruyama, 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 $$gamma$$-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 $$gamma$$-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 $$gamma$$-ray irradiation facilities were relevant to the Fukushima Daiichi nuclear disaster.

Journal Articles

Effect of temperature on the response of alanine dosimeters under low dose and long time irradiation

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

Journal Articles

The Effect of temperature on the response of alanine dosimeters under low dose and long time irradiation

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 20$$^{circ}$$C and 80$$^{circ}$$C 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.

Journal Articles

Utilization of the $$gamma$$-ray irradiation facilities and electron accelerator

Kaneko, 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 $$gamma$$-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.

Journal Articles

Operation of the electron accelerator and $$gamma$$-ray irradiation facilities

Haruyama, 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 $$gamma$$-ray irradiation facilities have been operated without serious troubles before the earthquake happened in March 11 2011. The electron accelerator and $$gamma$$-ray irradiation facilities were stopped with concern about the earthquake damage, for 13 and 20 days, respectively.

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