Neutron/-ray discrimination based on the property and thickness controls of scintillators using Li glass and LiCAF(Ce) in a -ray field

Kaburagi, Masaaki; Shimazoe, Kenji*; Terasaka, Yuta; Tomita, Hideki*; Yoshihashi, Sachiko*; Yamazaki, Atsushi*; Uritani, Akira*; Takahashi, Hiroyuki*

Nuclear Instruments and Methods in Physics Research A, 1046, p.167636_1 - 167636_8, 2023/01

https://doi.org/10.1016/j.nima.2022.167636

We focus on the thickness and property controls of inorganic scintillators used for thermal neutron detection in intense -ray fields without considering pulse shape discrimination techniques. GS20 (a lithium glass) and LiCaAlF:Ce(LiCAF:Ce) cintillators with thicknesses of 0.5 and 1.0 mm, respectively, have been employed. Pulse signals generated by photomultiplier tubes, to which the scintillators were coupled, were inserted into a digital pulse processing unit with 1 Gsps, and the areas of waveforms were integrated for 360 ns. In a Co -ray field, the neutron detection for GS20 with a 0.5-mm thickness was possible at dose rates of up to 0.919 Gy/h; however, for LiCAF:Ce, neutron detection was possible at 0.473 Gy/h, and it failed at 0.709 Gy/h. Threfore, in a Co -ray field, the neutron/-ray discrimination of GS20 was better than that of LiCAF:Ce due to its better energy resolution and higher detection efficiency.

Feasibility study of the one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10

https://doi.org/10.1115/1.4048841

For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and Sr/Y radioactive point source, basic properties of source position detection were confirmed.

Development of one-dimensional optical fiber type radiation distribution sensing method based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

Security measures at nuclear fuel facilities, 2; Internal threat countermeasure in cyber-security

Kono, Soma; Yamada, Hiroyuki; Goto, Atsushi*; Yamazaki, Katsuyuki; Nakamura, Hironobu; Kitao, Takahiko

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 2 Pages, 2018/11

no abstracts in English

A New method to analyze individual photosynthetic abilities of young plant seedlings using positron-emitting tracer imaging system (PETIS)

Kawachi, Naoki; Koyanagi, Atsushi*; Suzui, Nobuo; Ishii, Satomi; Yin, Y.-G.; Yamazaki, Haruaki; Iwasaki, Aya*; Ogawa, Kenichi*; Fujimaki, Shu

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 93, 2013/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2012-046.pdf

Operator's experience after introduction of random interim inspection at Tokai Reprocessing facilities

Makino, Risa; Ishiyama, Koichi; Kimura, Takashi; Yamazaki, Katsuyuki; Nakamura, Hironobu; Ikeda, Atsushi*; Yamaguchi, Katsuhiro*

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-33-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2012/10

The Integrated Safeguards (IS) applied to JNC-1 site began from August, 2008. At that time, the inspection scheme was replaced from Interim Inventory Verification (IIV) with scheduled day to Random Interim Inspection (RII) with short notice in order to strengthen deterrent against diversion of nuclear materials. To satisfy the requirements for IS in Tokai reprocessing facilities including Tokai Reprocessing Plant and Plutonium Conversion Development Facility, we have cooperated inspectorates to establish remote monitoring systems, and to introduce RII smoothly. Though the new inspection scheme requires additional efforts which contain keeping a certain number of operators every day and declaration of interim inventory lists in a short time, the whole inspection days per year during inter-campaign could be decreased to about 60% by comparing with the conventional IIV. This paper reports the effects after introduction of RII and the future tasks to be discussed regarding RII during campaign from the operator's standpoint.

29th report of ITPA topical group meeting

Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06

http://ci.nii.ac.jp/naid/40017204455

no abstracts in English

Horonobe Underground Research Laboratory project research and development plan in Phase 2; H20-21

Iwatsuki, Teruki; Sato, Haruo; Tanai, Kenji; Inagaki, Manabu; Sawada, Atsushi; Niinuma, Hiroaki; Ishii, Eiichi; Maekawa, Keisuke; Tomura, Goji; Sanada, Hiroyuki; et al.

JAEA-Research 2009-002, 156 Pages, 2009/05

JAEA-Research-2009-002.pdf:12.86MB

The research and development plan for geological investigation, engineering technology and safety assessment during the drilling of a shaft down to intermediate depth are summarized according to the Midterm Plan till 2009 Fiscal year of JAEA. This report describes subject, current status and programme in the "Phase 2: Construction phase" (investigations during construction of the underground facilities). Furthermore regarding R&D plan in next Midterm Plan of JAEA, preliminary ideas are summarized.

Long pulse production of high current D ion beams in the JT-60 negative ion source

Hanada, Masaya; Kamada, Masaki; Akino, Noboru; Ebisawa, Noboru; Honda, Atsushi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Mogaki, Kazuhiko; et al.

Review of Scientific Instruments, 79(2), p.02A519_1 - 02A519_4, 2008/02

https://doi.org/10.1063/1.2821508

A long pulse production of high-current, high-energy D ion beams was studied in the JT-60U negative ion source that was designed to produce 22 A, 500 keV D ion beams. Prior to the long pulse production, the short pulse beams were produced to examine operational ranges for a stable voltage holding capability and an allowable grid power loading. From a correlation between the voltage holding capability and a light intensity of cathodoluminescence from the insulator made of Fiber Reinforced Plastic insulator, the voltage holding was found to be stable at 340 kV where the light was sufficiently suppressed. The grid power loading for the long pulse operation was also decreased to the allowable level of 1 MW without a significant reduction of the beam power by tuning the extraction voltage (Vext) and the arc power (Parc). These allow the production of 30 A D ion beams at 340 keV from two ion sources at Vacc = 340 kV. The pulse length was extended step by step, and finally reached up to 21 s, where the beam pulse length was limited by the surface temperature of the beam scraper without water cooling. The D ion beams were neutralized to via a gas cell, resulting in a long pulse injection of 3.2 MW D beams for 21 s. This is the first long injection of 20 s in a power range of 3 MW.

Development of a neutron reflectometer SUIREN at JRR-3

Yamazaki, Dai; Moriai, Atsushi; Tamura, Itaru; Maruyama, Ryuji; Ebisawa, Toru*; Takeda, Masayasu; Soyama, Kazuhiko

JAEA-Technology 2007-030, 21 Pages, 2007/03

JAEA-Technology-2007-030.pdf:4.13MB

A new neutron reflectometer "SUIREN" has been developed and started its operation at the research reactor JRR-3 of JAEA in 2006. SUIREN (Apparatus for Surface and Interface investigations with Reflection of Neutrons) provides monochromatic neutron beam with wavelength of 3.8 and vertical sample geometry, which is suitable for studies on interfaces involving solid layers of soft materials, magnetic materials, neutron mirrors and many other things. Collimated neutron intensity is about 2.110 2.610 n/s/cm with =0.08 deg at the sample position. Background is as low as 4.510 n/s when a local beam shutter is closed. A demonstration experiment showed that specular reflectivity of a silicon substrate of 3 inches in diameter can be measured down to 10 over 0 Qz 0.22 in 27 hours. This paper describes the beam-line and components of the SUIREN reflectometer, some results of test measurements and future plans.