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JAEA Reports

Utilization of gamma ray irradiation at the WASTEF Facility

Sano, Naruto; Yamashita, Naoki; Watanabe, Masaya; Tsukada, Manabu*; Hoshino, Kazutoyo*; Hirai, Koki; Ikegami, Yuta*; Tashiro, Shinsuke; Yoshida, Ryoichiro; Hatakeyama, Yuichi; et al.

JAEA-Technology 2023-029, 36 Pages, 2024/03

JAEA-Technology-2023-029.pdf:2.47MB

At the Waste Safety Testing Facility (WASTEF), the gamma ray irradiation device "Gamma Cell 220" was relocated from the 4th Research Building of the Nuclear Science Research Institute in FY2019, and the use of gamma ray irradiation has begun. Initially, Fuel Cycle Safety Research Group, Fuel Cycle Safety Research Division, Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness, the owner of this device, conducted the tests as the main user, but since 2022, other users, including those outside the organization, have started using it. The gamma ray irradiation device "Gamma Cell 220" is manufactured by Nordion International Inc. in Canada. Since it was purchased in 1989, the built-in $$^{60}$$Co radiation source has been updated once, and safety research related to nuclear fuel cycles, etc. It is still used for this purpose to this day. This report summarizes the equipment overview of the gamma ray irradiation device "Gamma Cell 220", its permits and licenses at WASTEF, usage status, maintenance and inspection, and future prospects.

Journal Articles

Estimation of external dose for wild Japanese macaques captured in Fukushima prefecture; Decomposition of electron spin resonance spectrum

Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.

Radiation Protection Dosimetry, 199(14), p.1620 - 1625, 2023/09

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

We have been conducting dose assessments for Japanese macaques captured in Fukushima to reveal radiobiological effects on the low-dose expose animals. To accurately determine the external exposure dose, it is desirable to examine the analysis of the CO$$_{2}^{-}$$ radical intensity. We examined ESR spectra of teeth of 10 macaques captured in Fukushima by two spectrum-decomposition algorithms.

JAEA Reports

R&D and maintenance management of the WASTEF Facility (FY2021)

Sano, Naruto; Yamashita, Naoki; Hoshino, Kazutoyo*; Tsukada, Manabu*; Sawauchi, Fumiya*; Otake, Yoshinori; Ichise, Kenichi; Tagami, Susumu

JAEA-Technology 2022-034, 47 Pages, 2023/03

JAEA-Technology-2022-034.pdf:2.81MB

The Waste Safety Testing Facility (WASTEF) was established in 1982 as an experimental facility for long-term storage of solidified high-level radioactive waste generated in the reprocessing of spent light water reactor fuel and the subsequent safety assessment of geological disposal. It is a historic facility that started operation in 1982. This facility consists of 5 concrete cells, 1 lead cell, 6 glove boxes, and 7 hoods, and is a large-scale facility that can use nuclear fuel materials including uranium and plutonium and radioactive isotopes including TRU. In this facility, research and development requested by the research department is carried out in the Hot Material Examination Section. In addition, patrol inspections, self-inspections, etc. are also carried out as maintenance management based on safety regulations. This report summarizes the overview of WASTEF facilities, the results of operation, maintenance and management work in FY2021, and the future outlook.

Journal Articles

Radiation exposure and oxidative stress status of wild Japanese macaques in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident

Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.

KEK Proceedings 2022-2, p.61 - 66, 2022/11

The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.

Journal Articles

A Study on accuracy of analysis of the radiation-induced component in the ESR spectra of teeth

Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.

KEK Proceedings 2022-2, p.120 - 125, 2022/11

We investigate the effect of sample's anisotropy and measurement condition to obtain the higher reproducibility for the shape of the ESR spectrum and the intensity of CO$$_{2}^{-}$$ radical.

Journal Articles

Development of dose estimation method using wild animal teeth for low dose exposure

Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

KEK Proceedings 2021-2, p.91 - 96, 2021/12

We examined whether the ESR dose estimation method could be applied to wild Japanese macaque. In this work, we investigated the enamel preparation protocol and the analytical method of the ESR spectra.

Journal Articles

Performance evaluation of a solidification process for highly concentrated radiation contaminated surplus soil

Ishiyama, Shintaro; Otani, Kazuhisa*; Yamashita, Manabu*

Kagaku Kogaku Rombunshu, 40(6), p.466 - 469, 2014/11

 Times Cited Count:0 Percentile:0.00(Engineering, Chemical)

For the purpose of performance evaluation of the field portable (360 mmD $$times$$ 360 mmH $$times$$ 800 mmW) and fixed mount type filter presses(1880 mmD $$times$$ 2140 mmH $$times$$ 9085 mmW) for soil consolidation in radiation contaminated soil washing process, decontamination water washing test and radiation assessment for these filter presses were conducted with over 570,000 Bq/kg radiation contamination soil in FUKUSHIMA and the following results were derived; (1) About 10% volume reduction was achieved in soil consolidation process by the field portable filter press with 1.3-6.7 times high condensation of radiation density. (2) During soil consolidation, core dose in the field portable and fixed mount type were evaluated as 2.5 and 196 $$mu$$Sv/h, respectively, and exposed dose in ordinary maintenance and inspection in excess of radiation protection guide level, especially for the fixed mount type in terms of radiation protection.

JAEA Reports

Evaluation of irradiation behavior on oxide dispersion strengthened (ODS) steel claddings irradiated in Joyo/CMIR-6

Yano, Yasuhide; Otsuka, Satoshi; Yamashita, Shinichiro; Ogawa, Ryuichiro; Sekine, Manabu; Endo, Toshiaki; Yamagata, Ichiro; Sekio, Yoshihiro; Tanno, Takashi; Uwaba, Tomoyuki; et al.

JAEA-Research 2013-030, 57 Pages, 2013/11

JAEA-Research-2013-030.pdf:48.2MB

It is necessary to develop the fast reactor core materials, which can achieve high-burnup operation improving safety and economical performance. Ferritic steels are expected to be good candidate core materials to achieve this objective because of their excellent void swelling resistance. Therefore, oxide dispersion strengthened (ODS) ferritic steel and 11Cr-ferritic/martensitic steel (PNC-FMS) have been respectively developed for cladding and wrapper tube materials in Japan Atomic Energy Agency. In this study, the effects of fast neutron irradiation on mechanical properties and microstructure of 9Cr-and 12Cr-ODS steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the CMIR-6 at temperatures between 420 and 835$$^{circ}$$C to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures.

Journal Articles

Effect of fine precipitate on void swelling behavior in heavily-irradiated modified SUS316 stainless steels for fast reactor application

Yamashita, Shinichiro; Sekine, Manabu*; Akasaka, Naoaki

Materia, 47(12), P. 624, 2008/12

no abstracts in English

Oral presentation

Microstructural change of PNC-FMS under neutron irradiation, 2

Yano, Yasuhide; Yamashita, Shinichiro; Sekine, Manabu*; Yoshitake, Tsunemitsu; Akasaka, Naoaki

no journal, , 

no abstracts in English

Oral presentation

Effect of fine precipitate on swelling behavior of heavily-irradiated PNC316 stainless steel

Yamashita, Shinichiro; Sekine, Manabu*; Tachi, Yoshiaki; Akasaka, Naoaki; Nishinoiri, Kenji; Takahashi, Heishichiro

no journal, , 

no abstracts in English

Oral presentation

Microstructural evolutions of neutron-irradiated 11Cr ferritic and martensitic steels

Yamashita, Shinichiro; Tachi, Yoshiaki; Akasaka, Naoaki; Sekine, Manabu*

no journal, , 

no abstracts in English

Oral presentation

Influence on the oxidative stress status in liver and bladder of wild Japanese macaques in response to radiation exposure in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident

Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.

no journal, , 

In order to investigate the influence on the oxidative stress status by the long-term exposure after the Fukushima Daiichi Nuclear power plant (FNPP) accident, we analyzed oxidative stress markers in liver and bladder of wild Japanese macaques in the ex-evacuation zone. In liver, the concentration of malondialdehyde (MDA) in approximately 70% of the exposed group exceeded the average and SOD activity of the exposed group shifted toward lower within the range indicated in the control group. By contrast, alteration of MDA concentration and SOD activity in bladder was opposite to that shown in liver. We also found that oxidative stress markers changed in the same manner by external and internal exposure. Our data suggested that exposure to low dose/low dose-rate radiation following the FNPP accident may affect the sensitivity to oxidative stress by changing the activity of antioxidant enzymes.

Oral presentation

The Study of oxidative stress status in the organs of wild Japanese macaque affected by the accident of Fukushima Daiichi nuclear power plant

Suzuki, Masatoshi*; Ishikawa, Ryoya*; Oka, Toshitaka; Yamashita, Takuma*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Sato, Taku*; Isobe, Rio*; Chida, Koichi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Electron spin resonance study of radiation induced radical in hydroperoxide

Yamashita, Takuma*; Mitsuyasu, Yusuke*; Ono, Kenta*; Iwami, Satone*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

In order to clarify the radiation effects of the Fukushima Daiichi Nuclear Power Plant accident on living organisms, it is important to estimate the radiation dose to individual organisms. We have focused on carbonate radicals that induced in tooth enamel due to radiation, and have estimated the dose by using electron spin resonance technique. In this presentation, we report the results of dose response of radiation-induced radicals and the application of this method to low-dose area by using tooth enamel of Japanese macaque and hydroxyapatite.

Oral presentation

External exposure dose estimation using ESR dosimetry technique

Oka, Toshitaka; Takahashi, Atsushi*; Mitsuyasu, Yusuke*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Yamashita, Takuma*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

Electron spin resonance (ESR) dosimetry technique is a powerful tool that has been used in the study of external exposure dose assessment of human by measuring CO$$_{2}$$ radicals of teeth. In this work, we applied this technique for wild monkey and wild racoon captured in Fukushima prefecture, and estimated the external exposure dose.

Oral presentation

Dose estimation for animals exposed low dose using their teeth

Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

The improvement of the ESR dosimetry is required to apply that for the low-dose exposure of wild animals. We will report our progress of the improvement, and compare the external exposure dose estimated by the ESR dosimetry technique and the calculated result based on the external exposure dose rate of the captured point.

Oral presentation

Sample preparation procedure for ESR dosimetry using teeth of wild animal

Oka, Toshitaka; Mitsuyasu, Yusuke*; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Okutsu, Kenichi*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

Releases of the radioactive materials from the Fukushima Daiichi Nuclear Power Plant accident result in a low dose exposure to wild animals. The external dose of wild animals is commonly estimated by the external dose rate of the captured point, but the estimated exposure dose has huge uncertainties because the size of the habitat and/or the movement of the wild animals are not included in the estimation. To estimate the external dose precisely, we utilize electron spin resonance (ESR) dosimetry. In this work, we investigated the sample preparation procedure of wild animals. The ESR spectrum of enamel of racoon captured in Namie-town, Fukushima has a broad ESR signal due to metal components. The linear relationship between the Co$$_{2}$$ intensity and the absorbed dose that we can apply ESR dosimetry for racoon teeth. Using this relationship, the external exposure dose was estimated.

Oral presentation

Dosimetry of external exposure dose for wild Japanese macaques lived in Fukushima using tooth enamel

Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.

no journal, , 

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 resulted in a release of radionuclides into the environment and caused chronic low-dose-rate exposure to wildlife there. Studies of the radiobiological effects by the chronic low-dose-rate exposure was limited and there is a need for accurate determination of exposure doses and further studies of radiation effects by FDNPP accident. We determined dose of wild animals mainly captured in Namie Town, Fukushima Prefecture from the CO$$_{2}$$ radical intensities in tooth enamel by an electron spin resonance dosimetry.

Oral presentation

Tensile and ductile-brittle properties of the MEGAPIE samples evaluated by small punch (SP) tests

Saito, Shigeru; Wakui, Takashi; Tsukada, Manabu*; Yamashita, Naoki; Sano, Naruto; Dai, Y.*; Futakawa, Masatoshi

no journal, , 

Post irradiation examination (PIE) of the MEGAPIE (MEGAwatt Pilot Experiment) project has been performed on the samples allotted to JAEA. In the experiments, specimens for tensile test are prepared by taking from the component of the MEGAPIE target such as the beam window (BW) of T91. The irradiation temperatures were about 250 $$^{circ}$$C and the displacement-damage levels ranged between 0.75 and 1.74 dpa. After the tensile tests, SP specimens are prepared from the grip part of the tested tensile specimens. Testing temperatures for SP tests ranged from -150$$^{circ}$$C to 250$$^{circ}$$C. From the area of the load-displacement curves (LDC) of the SP tests, ductile-brittle transition temperature (DBTT) was evaluated. Comparison of these data with previous STIP data showed similar values. In addition, the yield stress and ultimate tensile strength were calculated from the SP tests results by applying the conversion equation. These were compared with the results of the tensile tests and found to be in good agreement.

23 (Records 1-20 displayed on this page)