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JAEA Reports

Decommissioning of the Plutonium Research Building No.1 (Plan and Present Status)

Komuro, Michiyasu; Kanazawa, Hiroyuki; Kokusen, Junya; Shimizu, Osamu; Honda, Junichi; Harada, Katsuya; Otobe, Haruyoshi; Nakada, Masami; Inagawa, Jun

JAEA-Technology 2021-042, 197 Pages, 2022/03


Plutonium Research Building No.1 was constructed in 1960 for the purpose of establishing plutonium handling technology and studying its basic physical properties. Radiochemical research, physicochemical research and analytical chemistry regarding solutions and solid plutonium compounds had been doing for the research program in Japan Atomic Energy Agency (JAEA). In 1964, the laboratory building was expanded and started the researching plutonium-uranium mixed fuel and reprocessing of plutonium-based fuel, playing an advanced role in plutonium-related research in Japan. Since then, the research target has been expanded to include transplutonium elements, and it has functioned as a basic research facility for actinides. The laboratory is constructed by concrete structure and it has the second floor, equipped with 15 glove boxes and 4 chemical hoods. Plutonium Research Building No.1 was decided as one of the facilities to be decommissioned by Japan Atomic Energy Agency Reform Plan in September 2014. So far, the contamination survey of the radioactive materials in the controlled area, the decontamination of glove boxes, and the consideration of the equipment dismantling procedure have been performed as planned. The radioisotope and nuclear fuel materials used in the facility have been transfer to the other facilities in JAEA. The decommissioning of the facility is proceeding with the goal of completing by decommissioning the radiation controlled area in 2026. In this report, the details of the decommissioning plan and the past achievements are reported with the several data.

JAEA Reports

Carrying-out of whole nuclear fuel materials in Plutonium Research Building No.1

Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.

JAEA-Technology 2021-001, 144 Pages, 2021/08


Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.

Journal Articles

Study of neutron-nuclear spin correlation term with a polarized Xe target

Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kakurai, Kazuhisa*; Shimizu, Hirohiko*; Hirota, Katsuya*; et al.

JPS Conference Proceedings (Internet), 33, p.011116_1 - 011116_6, 2021/03

In neutron fundamental physics, study of correlation term $${bf s}cdot{bf I}$$ of a neutron spin $${bf s}$$ and a target nuclear spin $${bf I}$$ is important because $${bf s}cdot{bf I}$$ term interferes to parity non-conserving (PNC) and time reversal non-conserving terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to $$ sim 10^{-1}$$ by using a spin exchange optical pumping (SEOP) method. We would plan to develop a polarized Xe gas target with a compact in-situ SEOP system, and to study $${bf s}cdot{bf I}$$ term by utilizing epithermal neutron beams supplied from a high intense pulsed spallation neutron source. As the first step, we attempted to measure neutron polarizing ability caused by $${bf s}cdot{bf I}$$ term at a 9.6 eV s-wave resonance peak of $$^{129}$$Xe at BL10 in MLF, by detecting change $$Delta R$$ of ratio between neutron transmissions with the polarized and unpolarized Xe target. After demonstrating that our apparatus could detect small change ($$Delta R_{rm DB} , {approx},10^{-2}$$) of neutron transmissions caused by Doppler broadening effect, a signified value of $$Delta R$$ has been obtained as preliminary results. For analyzing the obtained $$Delta R$$ in detail, we are improving our nuclear magnetic resonance and electron paramagnetic resonance systems for evaluating Xe polarization independently of neutron beams.

JAEA Reports

Decommissioning of the Uranium Enrichment Laboratory

Kokusen, Junya; Akasaka, Shingo*; Shimizu, Osamu; Kanazawa, Hiroyuki; Honda, Junichi; Harada, Katsuya; Okamoto, Hisato

JAEA-Technology 2020-011, 70 Pages, 2020/10


The Uranium Enrichment Laboratory in the Japan Atomic Energy Agency (JAEA) was constructed in 1972 for the purpose of uranium enrichment research. The smoke emitting accident on 1989 and the fire accident on 1997 had been happened in this facility. The research on uranium enrichment was completed in JFY1998. The decommissioning work was started including the transfer of the nuclear fuel material to the other facility in JFY2012. The decommissioning work was completed in JFY2019 which are consisting of removing the hood, dismantlement of wall and ceiling with contamination caused by fire accident. The releasing the controlled area was performed after the confirmation of any contamination is not remained in the target area. The radioactive waste was generated while decommissioning, burnable and non-flammable are 1.7t and 69.5t respectively. The Laboratory will be used as a general facility for cold experiments.

Journal Articles

Field emission-type scanning electron microscope for examination of irradiated fuels

Yasuda, Ryo; Mita, Naoaki; Nishino, Yasuharu; Nakata, Masahito; Nozawa, Yukio; Harada, Katsuya; Kushida, Teruo; Amano, Hidetoshi

Nuclear Technology, 151(3), p.341 - 345, 2005/09

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

The Field Emission type Scanning Electron Microscope (FE-SEM), which is one of effective tools for observation of micr-structures, was installed at the Reactor Fuel Examination Facility (RFEF) in JAERI. The FE-SEM is equipped in a large shield vessel with remote handling systems to keep safety of operators and is modified to enable to manipulate high radioactive materials. The Energy Dispersive Spectrometer (EDS) with radiation-shielded collimators has been also equipped on the FE-SEM to determine element compositions of the observed material samples. Characterization tests were carried out using deposited gold film and Zircaloy cladding tubes with hydrides to confirm the machine performance after the modifications. In the results of the tests, high-resolution images without some noises and fogs were obtained with high magnification above 10,000. Those results show that the FE-SEM keeps the high performance after some improvements and modifications for shielding $$gamma$$-rays and handling radioactive samples.

Journal Articles

Application of neutron imaging plate and neutron CT methods on nuclear fuels and materials

Yasuda, Ryo; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya; Amano, Hidetoshi; Sasajima, Fumio; Nishi, Masahiro; Horiguchi, Yoji

IEEE Transactions on Nuclear Science, 52(1), p.313 - 316, 2005/02

 Times Cited Count:14 Percentile:68.81(Engineering, Electrical & Electronic)

Neutron radiography is useful to inspect macroscopic change in nuclear fuels before and after irradiation. We have been investigated the practicality of neutron imaging plate and neutron CT methods for the inspection of the spent fuels. A fresh UO2 fuel rod was examined by those methods. The test results of those samples are available to develop the system of those methods for the spent fuels and to determine the specifications of the system. Some good images of those samples are obtained by those examinations. The shape of the pellets in the fuel rod is clearly recognized in the image. Those images are analyzed to estimate the size of some parts in the fuel pellets.

Journal Articles

Measurement of depth distributions of $$^{3}$$H and $$^{14}$$C induced in concrete shielding of an electron accelerator facility

Endo, Akira; Harada, Yasunori; Kawasaki, Katsuya; Kikuchi, Masamitsu

Applied Radiation and Isotopes, 60(6), p.955 - 958, 2004/06

 Times Cited Count:6 Percentile:41.48(Chemistry, Inorganic & Nuclear)

no abstracts in English

JAEA Reports

Development of pellet melting temperature measuring technique; Melting temperature measuring technique for small sample

Harada, Katsuya; Nakata, Masahito; Harada, Akio; Nihei, Yasuo; Yasuda, Ryo; Nishino, Yasuharu

JAERI-Tech 2004-034, 13 Pages, 2004/03


The Department of Hot Laboratories has been aiming the establishment of the melting temperature measuring technique for small samples obtained from the micro-region of irradiated fuel pellet. Due to the modification of the shape of tungsten capsule contained sample and the improvement of the detection method for melting temperature from indistinct thermal arrest point owing to small sample, it is possible to determine the melting temperature of small sample and to utilize effectively for the irradiated fuel pellet by using the existing apparatus. This paper describes the technique of the melting temperature measurement for small sample and the experimental results by using tantalum, molybdenum, hafnium oxide and un-irradiated UO$$_{2}$$ pellet.

Journal Articles

Application of hydrogen analysis by neutron imaging plate method to Zircaloy cladding tubes

Yasuda, Ryo; Nakata, Masahito; Matsubayashi, Masahito; Harada, Katsuya; Hatakeyama, Yuichi; Amano, Hidetoshi

Journal of Nuclear Materials, 320(3), p.223 - 230, 2003/08

 Times Cited Count:14 Percentile:67.72(Materials Science, Multidisciplinary)

Neutron radiography is one of effective tools to determine hydrided region in Zircaloy cladding tubes. In this work, the practicability of the neutron radiography for hydrogen analysis is further investigated by using standard samples with known hydrogen concentration. Local hydrogen concentration in hydrided Zircaloy tube is quantitatively estimated using the standard samples by neutron imaging plate (NIP) method. The local area is equivalent to a picture element in the image; e.g., 0.1mm$$times$$0.1mm. In addition, contribution of an oxide film in the tubes to the images is investigated using oxidized samples with hydrides or no hydride. In NIP images of oxidized tube no oxide film was recognized. Numerical image analysis also shows no effect of the oxide film on the image. These results show that the influence of oxygen on image contrast can be neglected when hydrogen analysis is performed on the Zircaloy tube with oxide film and hydrides by NIP method.

JAEA Reports

Development of remote controlled type field-emission type scanning electron microscope

Yasuda, Ryo; Nishino, Yasuharu; Mita, Naoaki; Nakata, Masahito; Harada, Katsuya; Nozawa, Yukio; Amano, Hidetoshi

JAERI-Tech 2002-081, 34 Pages, 2002/10


Information about the fuel behavior under high burn-up operation is needed to assess the safety of the high burn-up fuels. Microstructures in irradiated fuel pellets and Zircaloy tubes influence on their integrity. The fundamental information about microstructures is necessary to estimate the formation mechanism and change in the properties of the fuels.The Field Emission type Scanning Electron Microscope (FE-SEM) has been hence installed at the Reactor Fuel Examination Facility (RFEF). FE-SEM is designed for the remote handling type to use high radioactive materials and has equipments to keep safety for operators. Charctarization tests were carried out using Zircaloy cladding tubes with oxide films and hydrides to confirm machine performance. In the results of the tests, high-resolution images with a magnification of 30,000 were obtained. Those results show that the apparatus is maintained high performance as well as standard type.

Journal Articles

Application of neutron radiography for estimating concentration and distribution of hydrogen in zircaloy cladding tubes

Yasuda, Ryo; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya

Journal of Nuclear Materials, 302(2-3), p.156 - 164, 2002/04

 Times Cited Count:27 Percentile:84.09(Materials Science, Multidisciplinary)

no abstracts in English

JAEA Reports

Development of advanced neutron radiography for inspection on irradiated fuels and materials, 3; Examination of neutron imaging plate and computed tomography methods on unirradiated fuel rod

Yasuda, Ryo; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya; Amano, Hidetoshi; Ando, Hitoshi*; Sasajima, Fumio; Nishi, Masahiro; Horiguchi, Yoji

JAERI-Tech 2002-001, 23 Pages, 2002/02


Advanced neutron radiography techniques such as neutron imaging plate (NIP) and Computed Tomography (CT) methods have been investigated the practicality for Post Irradiation Examination (PIE). In this work, an unirradiated fuel rod was examined by NIP and CT methods in order to collect the fundamental data for applying these techniques to PIE.The fuel rod is composed of seven-enriched UO2 pellet and two-natural UO2 pellet that are loaded into a Zircaloy tube. There are somewhat difference in the size and shape among those UO2 pellets. A transmitted and cross-sectional images were obtained by NIP and CT methods, respectively.In the NIP image, the difference in the size, shape, and enrichment among the UO2 pellets is obviously recognized. In the case of CT method, the images clearly show the detailed shape of the cross section in the pellets, in addition, the difference in the enrichment between the natural and enriched pellets is recognized.

Journal Articles

Development of Neutron Multiplicity Measurement Method in ($$gamma$$,xn)Reactions

Harada, Hideo; Furutaka, Kazuyoshi; Shcherbakov, O.; Kinoshita, Tadashi*; Kato, Atsushi*; Katsuyama, Tomoyoshi*

Kakuriken Kenkyu Hokoku, 35, p.18 - 22, 2002/00


JAEA Reports

Development of advanced neutron radiography for inspection on irradiated fuels and materials, 2; Observation of hydride and oxide film on zircaloy cladding using by neutron radiography

Yasuda, Ryo; Nakata, Masahito; Matsubayashi, Masahito; Harada, Katsuya; Ando, Hitoshi*

JAERI-Tech 2000-082, 38 Pages, 2001/02


no abstracts in English

Journal Articles

Melting temperature of high burn-up UO$$_{2}$$ pellet

Harada, Katsuya; Nakata, Masahito; Yasuda, Ryo; Nishino, Yasuharu; Amano, Hidetoshi

HPR-356, 11 Pages, 2001/00

no abstracts in English

JAEA Reports

Development of pellet melting temperature measurement apparatus

Harada, Katsuya; Nishino, Yasuharu; Mita, Naoaki; Amano, Hidetoshi

JAERI-Tech 2000-031, p.27 - 0, 2000/03


no abstracts in English

JAEA Reports

Measurement of concentrations of $$gamma$$-ray emitters induced in the concrete shield of the JAERI electron linac facility

Endo, Akira; Kawasaki, Katsuya; Kikuchi, Masamitsu; Harada, Yasunori

JAERI-Tech 97-027, 28 Pages, 1997/07


no abstracts in English

Oral presentation

Experiments on microbes in TANPOPO mission on the International Space Station

Yokobori, Shinichi*; Kawaguchi, Yuko*; Harada, Miyu*; Murano, Yuka*; Tomita, Kaori*; Hayashi, Nobuhiro*; Tabata, Makoto*; Kawai, Hideyuki*; Okudaira, Kyoko*; Imai, Eiichi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Survivality of Deinococci under space conditions ?; Toward the space exposure experiment in "TANPOPO" mission at ISS

Murano, Yuka*; Harada, Miyu*; Kawaguchi, Yuko*; Hashimoto, Hirofumi*; Kobayashi, Kensei*; Nakagawa, Kazumichi*; Narumi, Issey*; Sato, Katsuya; Yoshida, Satoshi*; Yano, Hajime*; et al.

no journal, , 

Oral presentation

Investigation of the survivability of ${it Deinococcus}$ spp. under space

Kawaguchi, Yuko*; Yang, Y.*; Murano, Yuka*; Harada, Miyu*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Takasu, Masako*; Narumi, Issey*; Sato, Katsuya; Hashimoto, Hirofumi*; et al.

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)