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

JAEA-Technology-2021-042.pdf:16.87MB

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.

Deuterium concentration of co-deposited carbon layer produced at gap of wall tiles

Nobuta, Yuji*; Yokoyama, Kenji; Kanazawa, Jun*; Yamauchi, Yuji*; Hino, Tomoaki*; Suzuki, Satoshi; Ezato, Koichiro; Enoeda, Mikio; Akiba, Masato

Journal of Nuclear Materials, 417(1-3), p.607 - 611, 2011/10

https://doi.org/10.1016/j.jnucmat.2010.12.091

Production of soybean mutants with pale-green-leaf phenotype by ion beam irradiation

Arase, Sachiko*; Abe, Jun*; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issei; Kanazawa, Akira*

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 70, 2011/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2010-065.pdf

Vacuum system of the 3-GeV RCS in J-PARC

Ogiwara, Norio; Kinsho, Michikazu; Kamiya, Junichiro; Yamamoto, Kazami; Yoshimoto, Masahiro; Hikichi, Yusuke; Kanazawa, Kenichiro; Mio, Keigo; Takiyama, Yoichi; Suganuma, Kazuaki; et al.

Vacuum, 84(5), p.723 - 728, 2009/12

https://doi.org/10.1016/j.vacuum.2009.06.039

To minimize the radiation exposure during maintenance, it is necessary to compose the 3-GeV RCS vacuum system with reliable components which have long life time in such a high level of radiation. In addition, it is necessary to keep the operating pressure with beam in ultra high vacuum for suppressing the pressure instability. Thus we should think of not only the outgassing mainly due to ion desorption but also the pumping efficiency. From the above, the vacuum system was designed. The ring is divided by the isolation valves into 6 sections, which can be pumped down independently. For avoiding any eddy current loss ceramic ducts are used in the bending and focusing magnets. These ducts are connected to the Ti ducts, putting the Ti bellows between. Here, we adopt pure Ti as a material for the ducts and bellows because of its small residual radioactivity. The ring is evacuated with 20 ion pumps (0.7 m/s) and 24 turbomolecular pumps (TMPs) (1.3 m/s), which are attached to the Ti ducts. The TMPs are used for not only rough pumping but also evacuation during the beam operation. Especially a collimator system for localizing beam losses in a restricted area is evacuated with the TMPs, because the outgassing from this region will be probably the largest. On the other hand, each arc section is pumped by 4 ion pumps and 2 TMPs. To realize the above system, we have developed some components such as large aperture ceramic ducts and TMPs with high radioactive-resistance, as well as several kinds of heat treatment to reduce the outgassing. Finally, we have realized the UHV without baking in the RCS and the beam operation has been succeeded until now.

Effects of ion beam irradiation on soybean seeds evaluated by plant growth and seed-setting in a field

Kanazawa, Akira*; Abe, Jun*; Hase, Yoshihiro; Narumi, Issei

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 71, 2008/11

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2008-055.pdf

no abstracts in English

Measurement of the paint magnets for the beam painting injection system in the J-PARC 3-GeV RCS

Takayanagi, Tomohiro; Kanazawa, Kenichiro; Ueno, Tomoaki; Someya, Hirohiko*; Harada, Hiroyuki*; Irie, Yoshiro; Kinsho, Michikazu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.310 - 313, 2008/06

https://doi.org/10.1109/TASC.2008.920771

The beam painting injection system of the 3-GeV RCS in J-PARC, which realizes the uniform beam distributions in the ring, consists of four horizontal paint bump magnets and two vertical paint magnets. Each paint bump magnet power supply is required to excite the current with high accuracy that varies from 17.6 kA to zero during 0.5 msec. The IGBT chopper units, the switching frequency of which is 50 kHz each, are multiple connected to achieve the effective carrier frequency of 600 kHz. The output accuracy is then achieved to be less than 1 %. The measurements of the magnetic field with the actual current waveform were performed and the good performance was confirmed.

Field measurement of DC magnets at 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Ueno, Tomoaki; Togashi, Tomohito; Toyokawa, Ryoji; Takeda, Osamu; Watanabe, Masao; Yamazaki, Yoshio; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.301 - 305, 2008/06

https://doi.org/10.1109/TASC.2008.920832

Improved technique of hydrogen concentration measurement in fuel cladding by backscattered electron image analysis

Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu

JAEA-Conf 2006-003, p.212 - 221, 2006/05

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2006-003.pdf

In the Reactor Fuel Examination Facility (RFEF), a measuring method of hydrogen concentration by backscattered electron image analysis was improved to obtain more local hydrogen concentration data in fuel claddings. The sample preparation and image analysis procedures of this were able to measure hydrogen concentration efficiently and precisely.

Development of in-pile capsule for IASCC study at JMTR

Matsui, Yoshinori; Hanawa, Satoshi; Ide, Hiroshi; Tobita, Masahiro*; Hosokawa, Jinsaku; Onuma, Yuichi; Kawamata, Kazuo; Kanazawa, Yoshiharu; Iwamatsu, Shigemi; Saito, Junichi; et al.

JAEA-Conf 2006-003, p.105 - 114, 2006/05

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2006-003.pdf

Irradiation assisted stress corrosion cracking (IASCC) caused by the simultaneous effects of radiation, stress and high temperature water environment is considered to be one of the critical concerns of in-core structural materials not only for light water reactors (LWRs) but also for water-cooled fusion reactors. In the research field of IASCC, post-irradiation examinations (PIEs) for irradiated materials have been mainly carried out, because there are many difficulties on SCC tests under neutron irradiation environment. Hence we have embarked on a development of the test techniques for performing the in-pile SCC tests. In this paper, we describe the developed several in-pile test techniques and the current status of in-pile SCC tests at Japan Materials Testing Reactor (JMTR).

Quadrupole and hexadecapole ordering in DyBC; Direct observation with resonant X-ray diffraction

Tanaka, Yoshikazu*; Inami, Toshiya; Lovesey, S. W.*; Knight, K. S.*; Yakhou, F.*; Mannix, D.*; Kokubun, Jun*; Kanazawa, Masayuki*; Ishida, Kotaro*; Nanao, Susumu*; et al.

Physical Review B, 69(2), p.024417_1 - 024417_11, 2004/01

https://doi.org/10.1103/PhysRevB.69.024417

Direct evidence of the spatial ordering of Dy 4 quadrupole and hexadecapole moments in DyBC is demonstrated by resonant X-ray diffraction enhanced by an electric quadrupole event (2 resonance) at the Dy L absorption edge. The diffraction data show that the structural phase transition at = 24.7 K is accompanied by a reduction in the symmetry of the Dy site to 2/, from 4/, and the spatial ordering of the time-even Dy multipoles with A character. Below the crystal structure is described by the space group 4/ and Dy ions occupy sites (4). The distortion at T involves the lattice occupied by B and C ions, and it amounts to a buckling of B-C planes that are normal to the two-fold rotation axis of 2/. An immediately plausible model of low-energy Dy states correlates data on the specific heat, our X-ray diffraction signals, and magnetic ordering below 15.3 K which has been observed in magnetic neutron diffraction.