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-ray spectrometer and its performance under intense 
Cs and 
Co radiation fieldsKaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*
Nuclear Instruments and Methods in Physics Research A, 1010, p.165544_1 - 165544_9, 2021/09
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)The number of nuclear facilities being decommissioned has been increasing worldwide, in particular following the accident of the Tokyo Electric Power Company Holdings' Fukushima Daiichi Nuclear Power Station in 2011. In these nuclear facilities, proper management of radioactive materials is required. Then, A -ray spectrometer with four segmentations using small volume CeBr
scintillators with a dimension of 
was developed. The four scintillators were coupled to a multi-anode photomultiplier tube specific to intense radiation fields. We performed the -ray exposure study under Cs and Co radiation fields. Under the Cs radiation field, the relative energy resolution at 1375 mSv/h was the relative energy resolution at 1375 mSv/h was 9.2
0.05%, 8.00.08%, 8.0
0.03%, and 9.00.04% for the four channels, respectively.
scintillator under intense -ray fields for nuclear decommissioningKaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research A, 988, p.164900_1 - 164900_8, 2021/02
Times Cited Count：11 Percentile：87.80(Instruments & Instrumentation)An increasing number of nuclear facilities have been decommissioned worldwide following the 2011 accident of the TEPCO' Fukushima Daiichi Nuclear Power Station. During the decommissioning, radioactive materials have to be retrieved under proper management. In this study, a small cubic CeBr spectrometer with dimensions of 5 mm 
5 mm 5 mm was manufactured to perform -ray spectroscopy under intense -ray fields. Furthermore, thanks to a fast digital process unit and a customized photomultiplier, the device could perform -ray spectroscopy at dose rates of over 1 Sv/h. The energy resolution (FWHM) at 662 keV ranged from 4.4% at 22 mSv/h to 5.2% at 1407 mSv/h for a Cs radiation field. Correspondingly, at 1333 keV, it ranged from 3.1% at 26 mSv/h to 4.2% at 2221 mSv/h for a Co radiation field, which suggested to realize -ray assessment of 
Cs, Cs, Co, and 
Eu at dose rates of over 1 Sv/h.
gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power StationKaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Uenomachi, Mizuki*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08
Times Cited Count：7 Percentile：64.73(Instruments & Instrumentation)(Al,Ga)
O
scintillator Compton camera mounted on an unmanned helicopterShikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.
Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12
Times Cited Count：37 Percentile：96.33(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 44 to 88 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m 60 m and 65 m 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the -ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10
).
Yui, Mikazu; Ishikawa, Hirohisa; Watanabe, Atsuo*; Yoshino, Kyoji*; Umeki, Hiroyuki; Hioki, Kazumasa; Naito, Morimasa; Seo, Toshihiro; Makino, Hitoshi; Oda, Chie; et al.
JAEA-Research 2010-015, 106 Pages, 2010/05
JAEA-Research-2010-015.pdf:13.58MB
This report summarizes the activity of Phase I of Waste Management Working Group of the United States - Japan Joint Nuclear Energy Action Plan started in 2007. The working group focused on consolidation of the existing technical basis between the U.S. and Japan and the joint development of a plan for future collaborative activities. Firstly, the political/regulatory frameworks related to nuclear fuel cycles in both countries were reviewed. The various advanced fuel cycle scenarios in both countries were surveyed and summarized. Secondly, the waste management/disposal system optimization was discussed. Repository system concepts for the various classifications of nuclear waste were reviewed and summarized, then disposal system optimization processes and techniques were reviewed, and factors to consider in future repository design optimization activities were also discussed. Finally the potential collaboration areas and activities related to the optimization problem were extracted.
Morishita, Takatoshi; Ao, Hiroyuki; Asano, Hiroyuki; Ito, Takashi; Ueno, Akira; Okawa, Tomohiro; Hasegawa, Kazuo; Ikegami, Masanori*; Naito, Fujio*; Tanaka, Hirokazu*; et al.
Proceedings of 10th International Workshop on Accelerator Alignment (IWAA 2008) (Internet), 6 Pages, 2008/02
It has been widely accepted that an accurate alignment is essential to achieve high beam quality and highly stable operation increasingly demanded in recent particle accelerators. The J-PARC linac components are finely aligned based on the precise survey network, where we have emphasized on attaining the smoothness between adjacent elements. A floor elevation of the accelerator tunnel has been periodically measured since the completion of the linac building to correct the error by the settlement. The alignment of the linac components have been finished at Sep. 2006 and the beam commissioning has been started at Nov. 2006. After a coarse adjustment of the RF phase and amplitude, nearly complete beam transmission was easily established without using steering magnet. This successful beam transport proves the validity of the alignment strategy and the accurateness of the alignment procedure.
Morishita, Takatoshi; Asano, Hiroyuki; Ito, Takashi; Ueno, Akira; Hasegawa, Kazuo; Naito, Fujio*; Takasaki, Eiichi*; Tanaka, Hirokazu*; Yoshino, Kazuo*; Ikegami, Masanori*
Proceedings of 2007 Particle Accelerator Conference (PAC '07) (Internet), p.1523 - 1525, 2007/06
J-PARC linear accelerator components have been installed. The required alignment accuracy in the J-PARC linac is 0.1mm in transverse direction. In the DTL/SDTL section, the fine alignment was carried out by using an optical alignment telescope along with the cavity installation. The displacement of the DTL by the unit tank connection was monitored by a laser tracker to obtain the tolerable displacement between unit tanks. The heights of cavities and magnets were compensated form the unequal ground movement of the linac tunnel. Finally, all the cavities and magnets are aligned within the tolerable alignment error.
Ito, Takashi; Asano, Hiroyuki; Morishita, Takatoshi; Yamazaki, Yoshishige; Naito, Fujio*; Takasaki, Eiichi*; Yoshino, Kazuo*; Tanaka, Hirokazu*; Kato, Takao*; Kabeya, Zenzaburo*; et al.
Proceedings of 23rd International Linear Accelerator Conference (LINAC 2006) (CD-ROM), p.782 - 784, 2007/00
Three DTL tanks and 32 SDTL tanks for the Japan Proton Accelerator Research Complex (J-PARC) were assembled at KEK site. After the assembling, the high-power conditioning of the DTL1 and 12 SDTL tanks and the beam acceleration test for the DTL1 ware carried out. And then all the DTL and SDTL tanks have to be transported form KEK to JAEA. In order to confirm the effect of the transportation to the drift tube alignment, we measured the displacement of the drift tube positions before and after the transportation by using a prototype cavity. As a result of the test, the measured displacement of the drift tubes by the transportation was less than 0.02mm which is consistent in the measurement accuracy. Based on this result, all the DTL and SDTL tanks were transported form KEK to JAEA.
Morishita, Takatoshi; Asano, Hiroyuki; Ito, Takashi; Ikegami, Masanori*; Takasaki, Eiichi*; Tanaka, Hirokazu*; Naito, Fujio*; Yoshino, Kazuo*
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.376 - 378, 2006/00
In the J-PARC Linac, the DTL and the SDTL have been installed. A precise alignment of accelerator components is essential for high quality beam acceleration. Due to the heavy wiring for DTQs, the realignment of DTL cavity requires a long term. Then the DTL/SDTL and the focusing magnets are aligned precisely enough for the beam operation at the installation. The DTL/SDTL alignment accuracy satisfied the requirement, which confirmed by the laser tracker measurement. The floor level of the accelerator tunnel has been measured periodically. The long term motion of accelerator tunnel is quantitatively evaluated since Feb. 2005.
Morishita, Takatoshi; Ao, Hiroyuki; Ito, Takashi; Ueno, Akira; Hasegawa, Kazuo; Ikegami, Masanori*; Kubota, Chikashi*; Takasaki, Eiichi*; Tanaka, Hirokazu*; Naito, Fujio*; et al.
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.266 - 268, 2005/07
J-PARC linear accelerator components are now being installed in the accelerator tunnel. Markings are placed on the floor, which act as a reference for the initial alignment at the installation. A planned and ongoing alignment schemes for the installation of linac components and watching the long term motion of the building are described.
Ito, Takashi; Asano, Hiroyuki*; Morishita, Takatoshi; Kato, Takao*; Takasaki, Eiichi*; Tanaka, Hirokazu*; Yoshino, Kazuo*; Naito, Fujio*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.242 - 244, 2005/07
The third Drift Tube Linac (DTL3) is adopted for 37MeV-50MeV part of high intensity proton linac for Japan Proton Accelerator Research Complex(J-PARC). DTL3 consists of 26 full drift tubes, 2 half drift tubes and 26 post-couplers. As a result of tuning of the accelerating field of the DTL3, the resonant frequency was adjusted to 324MHz and the average accelerating field distribution was adjusted within 1%.
Nomoto, Kosuke*; Matsui, Mikio*; Inoue, Hiroyuki*; Yoshino, Naoto; Karasaki, Kenji*; Ito, Kazumasa*
JNC TJ8400 2005-005, 94 Pages, 2005/02
JNC-TJ8400-2005-005.pdf:7.92MB
In the safety assessment at geological disposal of High Level Nuclear Waste, it is necessary to understand several properties like hydrological, geological and chemical properties of the disposal site by site investigations. The investigation results should project to the ground water flow modeling, migration modeling and the parameter assignment of these models. Japan Nuclear cycle Development Institute is going to carry out two Underground Research Laboratory plans in order to push on with the project and help to make up the safety criteria of the geological disposal. Horonobe is one area of these plans. In Horonobe, following properties were identified./-There are saline and fresh water./-There is dissolved gas in the underground water./-The underground of some area has high water pressure./In this study, the analysis considering above properties were carried out for understanding of hydrological properties in sedimentary rock. In addition, the affection to the water flow and migration influenced by the results were examined.
Yoshino, Naoto; Miyanomae, Shunichi*; Inoue, Hiroyuki*; Nashimoto, Yutaka*
JNC TJ8400 2005-004, 166 Pages, 2005/02
JNC-TJ8400-2005-004.pdf:4.59MB
In this paper, following two issues were examined and estimated, (1) The influence of near field condition factor to the dynamical behavior of sedimentary soft rock (2) The long term estimation of the dynamical behavior considering the condition of Horonobe area As the study about the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, the thermal factor was focused on and the laboratory tests using test pieces which were sampled in Horonobe area were carried out under the water temperature were 20 degrees and 80 degrees. As a result, the time dependence parameter in variable-compliance-type constitutive-equation could be obtained. And comparison between creep property under 20 degrees and 80 degrees was conducted. In addition, the general properties of sedimentary soft rock under several conditions were identified by the survey of the literature. And the way how to confirm the dynamical properties of sedimentary soft rock with in-situ test were presented. For the study on the short-term and long-term stability of rock surroundig buffer materials, numerical simulations were carried out assuming several conditions. The direction of disposal tunnels and the ratio of rock strength by initial stress were estimated to be the main factor affecting the short-term stability of rock. Time dependency of rock and the stiffness of buffer material were estimated to be the main factor affecting the long-term stability of rock.
Morishita, Takatoshi; Ao, Hiroyuki; Ito, Takashi; Ueno, Akira; Hasegawa, Kazuo; Ikegami, Masanori*; Kubota, Chikashi*; Naito, Fujio*; Takasaki, Eiichi*; Tanaka, Hirokazu*; et al.
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2851 - 2853, 2005/00
In J-PARC linac, a precise alignment of accelerator components is essential for high quality beam acceleration. Markings have been placed on the floor, which act as a reference for the initial alignment at the installation. For a straight line alignment, the wire position sensor is placed on the offset position with respect to the beam center by a target holder. The hydrostatic levering system is used for watching the floor elevation over the long period.
Kondo, Yasuhiro; Akikawa, Hisashi; Anami, Shozo*; Asano, Hiroyuki*; Fukui, Yuji*; Igarashi, Zenei*; Ikegami, Kiyoshi*; Ikegami, Masanori*; Ito, Takashi; Kawamura, Masato*; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.156 - 158, 2004/08
A commissioning of the J-PARC linac DTL1 is now under way at KEK. A 30mA H
beam was accelerated to 19.7-MeV, and 100% transmission was obtained with a 20-msec-pulse-width and 12.5-Hz-repetition beam. In this paper, present status of the DTL1 commissioning and preliminary results of the commissioning, such as emittance measurements, are presented.
Morishita, Takatoshi; Ao, Hiroyuki; Ito, Takashi; Ueno, Akira; Hasegawa, Kazuo; Ikegami, Masanori*; Kubota, Chikashi*; Takasaki, Eiichi*; Tanaka, Hirokazu*; Naito, Fujio*; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.671 - 673, 2004/08
A precise alignment of accelerator components is essential for the J-PARC linear accelerator. The wire position sensor is applied to measure the accelerator component positioning and the ground motion of the building is measured by the hydrostatic leveling sensors. In this paper, the scheme of the alignment system is presented.
Inoue, Hiroyuki*; Ishiguro, Takeshi*; Kuji, Masayoshi*; Yoshino, Naoto
JNC TJ8400 2004-014, 59 Pages, 2004/02
JNC-TJ8400-2004-014.pdf:5.57MB
In this paper, authors examined the properties of sedimentary soft rock which might affect the groundwater flow rate and flow path in the sedimentary soft rock. As a general sample of sedimentary soft rock, we focused on the rock of HORONOBE area in HOKKAIDO prefecture. Then, following four issues were examined.1) a study of numerical flow rate analysis considering the difference of water density in the sedimentary soft rock.2) the hydro-geological modeling of HORONOBE area and a fundamental study of water pressure and saline density in HORONOBE area.3) a fundamental study of numerical coupling analysis about groundwater flow rate ,the difference of underground temperature, rock pressure and deformation. 4) a study about best performance of numerical flow rate analysis program.As a result, hydro-geological modeling of HORONOBE area using the information before 2002 as input data was succeeded by using the basic geological model which was made by IMAI et al,. And the applicability of TOUGH2 program as analysis method considering the density difference of underground water in sedimentary soft rock was verified. Then, we will be able to simulate underground flow considering the difference of saline density and specific water pressure in HORONOBE area. In addition, the applicability of TOUGH-FLAC program in which TOUGH2 was coupled with FLAC3D and consider rock pressure and deformation was verified. The best numerical performance of TOUGH2 program was studied in order to deal with large scale simulations. Then, it was shown that efficient method of the best numerical performance about TOUGH2 was possible.
Inoue, Hiroyuki*; Ishiguro, Takeshi*; Kuji, Masayoshi*; Yoshino, Naoto
JNC TJ8400 2004-013, 137 Pages, 2004/02
JNC-TJ8400-2004-013.pdf:22.48MB
In this paper, authors examined the properties of sedimentary soft rock which might affect the groundwater flow rate and flow path in the sedimentary soft rock. As a general sample of sedimentary soft rock, we focused on the rock of HORONOBE area in HOKKAIDO prefecture. Then, following four issues were examined. 1) a study of numerical flow rate analysis considering the difference of water density in the sedimentary soft rock. 2) the hydro-geological modeling of HORONOBE area and a fundamental study of water pressure and saline density in HORONOBE area. 3) a fundamental study of numerical coupling analysis about groundwater flow rate ,the difference of underground temperature, rock pressure and deformation. 4) a study about best performance of numerical flow rate analysis program. As a result, hydro-geological modeling of HORONOBE area using the information before 2002 as input data was succeeded by using the basic geological model which was made by IMAI et al,. And the applicability of TOUGH2 program as analysis method considering the density difference of underground water in sedimentary soft rock was verified. Then, we will be able to simulate underground flow considering the difference of saline density and specific water pressure in HORONOBE area. In addition, the applicability of TOUGH-FLAC program in which TOUGH2 was coupled with FLAC3D and consider rock pressure and deformation was verified. The best numerical performance of TOUGH2 program was studied in order to deal with large scale simulations. Then, it was shown that efficient method of the best numerical performance about TOUGH2 was possible.
Inoue, Hiroyuki*; Yoshino, Naoto; Miyanomae, Shunichi*; Mizutani, Kazuhiko*; Noda, Kenji*
JNC TJ8400 2004-005, 161 Pages, 2004/02
JNC-TJ8400-2004-005.pdf:18.59MB
In this study, the laboratory mechanical tests of sedimentary soft rock sampled at HORONOBE area in HOKKAIDO prefecture were conducted in order to build the confidence of OKUBO model for long term deformation of sedimentary rock. And the stability of rock around tunnel in building under the condition assumed the underground of HORONOBE area was examined by numerical simulation using information of boring data obtained before 2002 year. As a result, authors could obtain many values of parameter in OKUBO model under various conditions. These conditions have the difference of temperature and water saturation. In addition, the life time in creep predicted by OKUBO model could be compared with the real one. And numerical simulations, assuming various conditions such as stiffness of buffer material and yielding of support, had been carried out to evaluate the long-term stability of rock surrounding buffer material. Results show the decreasing tendency of time dependency of rock.
-ray spectrometry system specific to high dose-rate radiation fields for the retrieval of nuclear fuel debris in Tokyo Electrical Power Company Holdings' Fukushima Daiichi Nuclear Power StationKaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.
no journal, ,
The retrieval of nuclear fuel debris will be started at Tokyo Electrical Power Company Holdings' Fukushima Daiichi Nuclear Power Station. Because of high dose-rate fields on the surface of nuclear fuel debris and these inhomogeneous elements, non-destructive analysis is required during the retrieval. Here, it is presented that a -ray spectrometry system specific to high dose-rate fields was developed and its performance under intense -ray fields was evaluated for the retrieval of nuclear fuel debris.
