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Journal Articles

Evaluation of oxidation efficiency of hydrophobic palladium catalyst for $$^{3}$$H monitoring in radioactive gaseous waste

Furutani, Misa; Kometani, Tatsunari; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya; Iwai, Yasunori*

Hoken Butsuri (Internet), 55(2), p.97 - 101, 2020/06

Herein, an oxidation catalyst was introduced after heating it to 600$$^{circ}$$C to oxidize tritium gas (HT) existing in exhaust into tritiated water vapor (HTO). This study aims to establish a safer $$^{3}$$H monitoring system by lowering the heating temperature required for the catalyst. In these experiments, which were conducted in the Nuclear Science Research Institute, Japan Atomic Energy Agency, cupric oxide, hydrophobic palladium/silicon dioxide (Pd/SiO$$_{2}$$), and platinum/aluminum oxide (Pt/Al$$_{2}$$O$$_{3}$$) catalysts were ventilated using standard hydrogen gas. After comparing the oxidation efficiency of each catalyst at different temperatures, we found that the hydrophobic Pd/SiO$$_{2}$$ and Pt/Al$$_{2}$$O$$_{3}$$ catalysts could oxidize HT into HTO at 25$$^{circ}$$C.

Journal Articles

Activity report of the task group of radiation protection about wastes containing natural radioactive nuclides

Saito, Tatsuo; Kobayashi, Shinichi*; Zaitsu, Tomohisa*; Shimo, Michikuni*; Fumoto, Hiromichi*

Hoken Butsuri (Internet), 55(2), p.86 - 91, 2020/06

Safety cases for disposal of uranium bearing waste and NORM with uranium has not yet been fully developed in Japan, because of safety assessment of extraordinary long timespan and uncertainty in unexpected incidents with uncompleted radon impact evaluation measures arising from uranium waste disposal facility in far future. Our task group of radiation protection for wastes with natural radioactive nuclides studied some safety cases with disposal of uranium bearing waste and NORM in terms of nuclides, U-235, U-238 and their progenies, and comprehensively discussed the current state of their disposal in comparison to the ideas of international organizations such as ICRP and IAEA. We developed our ideas for long term uncertainty and radon with the knowledge of experts in each related area of direction, repeating discussions, focusing out the orientation of each directions, and outlined the recommendations with our suggestions of solving important issues in the future to be addressed.

Journal Articles

A Knowledge-sharing activity on the environmental radiation monitoring results affected by the Fukushima-Daiichi Nuclear Power Plant Accident at Tokai-Oarai area in Ibaraki Prefecture

Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.

Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06

After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, $$^{134}$$Cs/$$^{137}$$Cs activity ratio, and so on. In this report, the results of the dose rate and $$^{137}$$Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.

Journal Articles

Impressions of Japan Health Physics Society Lecture, "Domestic Trend about Incorporating ICRP Recommendations"

Maeda, Tsuyoshi

Hoken Butsuri (Internet), 54(4), p.220 - 221, 2019/12

no abstracts in English

Journal Articles

Corrigenda; Review on the gross beta activity in rainwater observed throughout Japan in 1954

Tsujimura, Norio

Hoken Butsuri (Internet), 54(4), P. 205, 2019/12

no abstracts in English

Journal Articles

Participation report of ICRP/JAEA Dialogue Meeting

Maeda, Tsuyoshi; Endo, Yuya; Uezu, Yasuhiro

Hoken Butsuri (Internet), 54(3), p.177 - 180, 2019/10

no abstracts in English

Journal Articles

Establishment and activities of Young Generation Network (IRPA YGN) in International Radiation Protection Association

Sakoda, Akihiro; Kono, Takahiko; Kataoka, Noriaki*; Andresz, S.*

Hoken Butsuri (Internet), 54(3), p.181 - 187, 2019/10

no abstracts in English

Journal Articles

Joint meeting of young researchers in the field of radiation protection and radiation biology

Kataoka, Noriaki*; Nakajima, Junya; Miwa, Kazuji; Hirota, Seiko*; Tsubota, Yoichi; Yamada, Ryohei; Fujimichi, Yuki*; Ishikawa, Junya*; Sunaoshi, Masaaki*

Hoken Butsuri (Internet), 54(2), p.140 - 145, 2019/06

It is the written report of the joint meeting of young researchers in the field of radiation protection and radiation biology.

Journal Articles

Investigation of removal factors of various materials inside houses after Nuclear Power Station Accident

Mori, Airi; Ishizaki, Azusa; Futemma, Akira; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro

Hoken Butsuri (Internet), 54(1), p.45 - 54, 2019/04

Journal Articles

Review on the gross beta activity in rainwater observed throughout Japan in 1954

Tsujimura, Norio

Hoken Butsuri (Internet), 54(1), p.40 - 44, 2019/03

Rainwater containing radioactive materials originating from the USA's nuclear weapon test conducted at Bikini Atoll was observed throughout Japan in 1954. It has been reported that the maximum gross beta activity observed at that time in Kyoto was 523 pCi/mL (19,000 Bq/L). This measurement, however, focused on the gross beta activity contained in a small amount of rain sampled at the beginning of rainfall, which is different from present observations that are based on the average gross beta activity contained in rain collected during a 24-h period. As a result of reviewing and converting the 1954 data to be equivalent to current measurement, the maximum value was reduced to 50 pCi/mL (1,800 Bq/L), with a resultant surface deposition density of 310 mCi/km$$^{2}$$ (11,000 MBq/km$$^{2}$$). These values are well below 1/10 of the past maximum observed a few days after China's fifth nuclear weapon test in 1966.

Journal Articles

Evaluation of a surface collection efficiency and a stability of flow rate for the commercially available filters used for ambient radioactive aerosols

Tamakuma, Yuki*; Yamada, Ryohei; Iwaoka, Kazuki*; Hosoda, Masahiro*; Tokonami, Shinji*

Hoken Butsuri (Internet), 54(1), p.5 - 12, 2019/03

Airborne radioactivity measurements are necessary to know the contamination level and internal doses for residents after a nuclear accident. In addition, measurements of radon progenies in air, which are the risk factor of lung cancer, are also important to evaluate lung dose. In these measurements, a filter sampling is used to collect radioactive aerosols. However, it is well known that results of the measurement using a filter are strongly dependent on characteristics of the used filter. Selection of a suitable filter is important to achieve the high-resolution and long-term measurement. "Surface collection efficiency (SCE)" and "stability of air flow rate" were examined for six types of filter that are commercially available in Japan. In Japan, cellulose-glass fiber filter paper (HE-40T) is used for an environmental monitoring in Japan. In this study, it was found that the SCE of HE-40T was lower than that of mixed cellulose ester type membrane filter by Merck Millipore (DAWP02500). Attenuation ratio of flow rate for DAWP02500 was evaluated to be 2.9% which was lowest in six filters. The results suggest that the DAWP02500 is the most suitable for collecting radioactive aerosols for a long term.

Journal Articles

Report on participation in the 5th Asian and Oceanic Congress on Radiation Protection (AOCRP-5)

Sakoda, Akihiro; Okazaki, Toru*; Hashizume, Takuya*

Hoken Butsuri (Internet), 53(3), p.197 - 200, 2018/09

This article gives the report on participation in the 5th Asian and Oceanic Congress on Radiation Protection (AOCRP-5), which was held in Melbourne, Australia on between May 20th and 23rd, 2018.

Journal Articles

Journal Articles

Construction of adult Japanese voxel phantoms with various body sizes and their applications to evaluation of organ doses due to external photon irradiation

Sato, Kaoru; Takahashi, Fumiaki

Hoken Butsuri, 52(4), p.247 - 258, 2017/12

Organ doses for dose assessment in radiation protection are derived from ICRP reference phantoms (Male:RCP-AM, Female:RCP-AF) with standard Caucasian physiques. In adult, Japanese are smaller than Caucasian. To study impact of differences in physiques between Caucasian and Japanese on organ doses, we previously constructed Japanese phantoms (Male:JM-103, Female:JF-103) with average adult Japanese physiques. In addition, adult Japanese physiques have also wide distribution. Thus, we newly modeled DJM (Male) and DJF (Female) with 8 physiques by changing the perimeters of JM-103 and JF-103. Organ doses due to external photon irradiation of DJM and DJF were calculated, and were compared with those of RCP-AM and RCP-AF. In ISO geometry at 0.3 MeV, it was found that doses of breast, colon, lung, stomach, gonad, urinary bladder, esophagus, liver and thyroid in DJM and DJF with physiques, which are applicable to most adult Japanese, agreed with those of RCP-AM and RCP-AF within 10%.

Journal Articles

Setting of the normal variation range for the environmental radiation monitoring around the Tokai Reprocessing Plant after the TEPCO's nuclear accident

Nakano, Masanao; Hosomi, Kenji; Hokama, Tomonori

Hoken Butsuri, 52(4), p.275 - 284, 2017/12

no abstracts in English

Journal Articles

Mechanisms and modeling approaches of radon emanation for natural materials

Sakoda, Akihiro; Ishimori, Yuu

Hoken Butsuri, 52(4), p.296 - 306, 2017/12

Radon emanation means the escape of radon atoms from solid grains into pore space; it is the very first process that may lead to radon exposure in the environment. Experimental and numerical studies of radon emanation have been diligently carried out since its recognition as a carcinogen. Our previous review of the measured data showed a wide range of radon emanation fractions from natural substances, and then we discussed the effects of environmental factors such as pore water. The present paper provides an overview of the approaches and progress of radon emanation modeling that may be useful for the interpretation of measured data. Recoil and/or diffusion of radon in solid following alpha decay of radium, which underlies the mechanisms of radon emanation, have been incorporated into numerical models. In the calculation based on recoil-based emanation, radium distribution and pore size were the most important parameters, which govern the magnitudes of radon ejections from the birth grain and of radon embedding into another solid surface, respectively. The solid diffusion appeared significant only at a temperature higher than a few hundred degrees Celsius. A model is now desired to be developed that incorporates the transport process of radon atoms that are still settled in solid after alpha recoil, considering radiation damage and its resulting inner path network.

Journal Articles

Revised version of Dosimetry System 2002 (DS02R1)

Furuta, Takuya

Nippon Hoken Butsuri Gakkai Homu Peji (Internet), 2 Pages, 2017/10

The current standard of the international radiation protection is determined through life span study of atomic bomb survivors of Hiroshima and Nagasaki, and individual radiation dose estimates for each survivor calculated by Dosimetry System 2002 (DS02). Dose estimates in DS02 are based on input data such as location and shielding condition of the survivor. Therefore accuracy of dose estimates and accordingly that of radiation risk evaluation are largely affected by the accuracy of the input data. In this review, we present an article DS02R1 discussed improvement of the input data of individual atomic bomb survivors for DS02 and its consequence keeping the core system unchanged.

Journal Articles

Present status and issues of dosimetry for the lens of the eye at the MOX-fuel plant

Yamazaki, Takumi; Takada, Chie; Tsujimura, Norio; Okada, Kazuhiko

Hoken Butsuri, 52(3), p.167 - 170, 2017/09

At the JAEA MOX Fuel Facilities, a worker engaged in glove box operations uses two personal dosemeters, one worn on the trunk under a protective apron and the other at the collar over the apron. The recorded lens of the eye dose is based on the photon dose measured by the collar dosemeter plus the neutron dose measured by the under-apron dosemeter.

Journal Articles

Evaluation of effective dose coefficient with variation of absorption fraction in gastrointestinal system for ingestion of radiocesium

Pratama, M. A.; Takahara, Shogo; Hato, Shinji*

Hoken Butsuri, 52(3), p.200 - 209, 2017/09

The purpose of this study is to identify the significance of the change in the intestinal absorption rate values the ($$f_{1}$$ value) to the change of dose coefficient as well as to provide a list of dose coefficients which each of the value corresponds to a specific intestinal absorption rate and age groups. In the range of 0-1, 10 different values of $$f_{1}$$ for 1 year, 5 years old, and adult group were chosen and used in a separate calculation by using, a biokinetic compartment model, DCAL. It was found that the lower values of intestinal absorption rate lead to a significant decrease of the committed effective coefficient for adult. Oppositely for children, the decrease of committed effective coefficient was not as significant. This study also suggests that the significance of dose coefficient change due to the variation of $$f_{1}$$ substantially depends on the biological half-life of the radionuclide and the mass of organs and tissues in human body.

Journal Articles

Report on a Workshop of the 23th Young Researchers Association, a Fukushima Daiichi Nuclear Power Plant tour and the 10th Conference of Students Association of the Japan Health Physics Society

Matsuyama, Tsugufumi*; Suzuki, Tatsuhiko*; Migita, Yukie; Ishii, Kota*; Ueno, Satoshi*

Hoken Butsuri, 52(3), p.226 - 230, 2017/09

no abstracts in English

467 (Records 1-20 displayed on this page)