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Senzaki, Tatsuya; Arai, Yoichi; Yano, Kimihiko; Sato, Daisuke; Tada, Kohei; Ogi, Hiromichi*; Kawanobe, Takayuki*; Ono, Shimpei; Nakamura, Masahiro; Kitawaki, Shinichi; et al.
JAEA-Testing 2022-001, 28 Pages, 2022/05
In preparation for the decommissioning of Laboratory B of the Nuclear Fuel Cycle Engineering Laboratory, the nuclear fuel material that had been stored in the glove box for a long time was moved to the Chemical Processing Facility (CPF). This nuclear fuel material was stored with sealed by a polyvinyl chloride (PVC) bag in the storage. Since it was confirmed that the PVC bag swelled during storage, it seems that any gas was generated by radiolysis of the some components contained in the nuclear fuel material. In order to avoid breakage of the PVC bag and keep it safety for long time, we began the study on the stabilization treatment of the nuclear fuel material. First, in order to clarify the properties of nuclear fuel material, radioactivity analysis, component analysis, and thermal analysis were carried out. From the results of thermal analysis, the existence of organic matter was clarified. Then, ion exchange resin with similar thermal characteristics was selected and the thermal decomposition conditions were investigated. From the results of these analyzes and examinations, the conditions for thermal decomposition of the nuclear fuel material contained with organic matter was established. Performing a heat treatment of a small amount of nuclear fuel material in order to confirm the safety, after which the treatment amount was scaled up. It was confirmed by the weight change after the heat treatment that the nuclear fuel material contained with organic matter was completely decomposed.
Shibata, Takanori*; Okoshi, Kiyonori; Shinto, Katsuhiro; Nammo, Kesao*; Ikegami, Kiyoshi*; Oguri, Hidetomo
Journal of Physics; Conference Series, 2244, p.012041_1 - 012041_5, 2022/04
In the J-PARC user operation from Nov. 2020 - Apr. 2021, continuous operation of J-PARC Radio Frequency (RF) negative hydrogen ion (H) source up to 3,651 hours (5 months) has been achieved. The ion source was operated with the output H
current of 60 mA, the duty factor (for plasma generation) 2% and the input RF power up to 30 kW. After the operation, phase space diagrams at the Radio Frequency Quadrupole (RFQ) entrance were measured by the emittance monitor at the ion source test stand (IS-TS) under the same operation condition as in the J-PARC Linac. Comparison of the phase spaces and the beam emittances between the ion sources in the present and the previous operations shows slight difference. From the direct observation of the antenna coil, no exhaustion or the decrease in the thickness of the enamel coating of the coil have been confirmed. The results indicate the possibility of the next goal of the long-run up to 7 months, which is the same as the full duration of the J-PARC user operation in 1 year.
Grambow, B.; Nitta, Ayako; Shibata, Atsuhiro; Koma, Yoshikazu; Utsunomiya, Satoshi*; Takami, Ryu*; Fueda, Kazuki*; Onuki, Toshihiko*; Jegou, C.*; Laffolley, H.*; et al.
Journal of Nuclear Science and Technology, 59(1), p.1 - 24, 2022/01
Times Cited Count:0 Percentile:0.37(Nuclear Science & Technology)Shinto, Katsuhiro; Shibata, Takanori*; Wada, Motoi*
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.230 - 233, 2021/10
In most proton accelerator facilities such as J-PARC, SNS, CERN, a H ion source equipped with a 2-MHz rf driver for plasma generation produces H
beams. We have reported H
beam characteristics extracted from the J-PARC rf-driven high-intensity H
ion source. We have been developing an emittance measurement apparatus equipped with a highly time-resolved data acquisition system in order to observe fluctuation of the beam emittance in association with the frequency of the rf driver. By using this apparatus, we found that the beam emittance is fluctuated with the frequency with the rf driver and higher harmonics. We will show some obtained results of the emittance fluctuation.
Shibata, Takanori*; Hirano, Koichiro; Hirane, Tatsuya*; Shinto, Katsuhiro; Hayashi, Naoki; Oguri, Hidetomo
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.417 - 421, 2021/10
In J-PARC linac, the operation of an rf-driven high-intensity H ion source was initiated in 2014. For plasma ignition, the 2-MHz rf amplifier outputs the power of several tens kW. However the rf amplifier for the ion source and those for the accelerating cavities have not been synchronized. As a result, the wave hights in the beam waveforms were different in shot by shot. Therefore, we have developed an synchronization system between the rf system for the ion source and those for the cavity systems and succeeded the same wave hights in the waveforms.
Igarashi, Go*; Haga, Kazuko*; Yamada, Kazuo*; Aihara, Haruka; Shibata, Atsuhiro; Koma, Yoshikazu; Maruyama, Ippei*
Journal of Advanced Concrete Technology, 19(9), p.950 - 976, 2021/09
Aihara, Haruka; Watanabe, So; Shibata, Atsuhiro; Mahardiani, L.*; Otomo, Ryoichi*; Kamiya, Yuichi*
Progress in Nuclear Energy, 139, p.103872_1 - 103872_9, 2021/09
Shibata, Takanori*; Shinto, Katsuhiro; Wada, Motoi*; Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Nammo, Kesao*
AIP Conference Proceedings 2373, p.050002_1 - 050002_9, 2021/08
Oscillation of emittance and Twiss parameters in the negative ion beam from the J-PARC 2-MHz RF ion source is measured by applications of a double-slit emittance monitor located at the RFQ (Radio Frequency Quadrupole) entrance. The emittance monitor is equipped with a newly-developed 60 MS/s data acquisition system, so that beam current oscillation in a few MHz can be observed with enough time resolution. From the measurement, it is shown that the beam phase space consists of (1) a DC component in the beam core, (2) a 2-MHz oscillating component which takes place both in the beam core and the halo and (3) a doubled RF frequency (4 MHz) oscillation which slightly exists in the beam halo. The major component is the 2-MHz component, which resultantly decides the beam emittance oscillation frequency. A typical value of the beam emittance in the present experiment is 0.34 mm-mrad, while the amplitude of the 2 MHz oscillation is around 0.04
mm-mrad. The results indicate that the high-frequency oscillation component occupying about ten-percent of the beam from the RF source travels a few meters passing through a magnetic lens focusing system.
Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Watanabe, So; Shibata, Atsuhiro; Nomura, Kazunori
JAEA-Technology 2021-007, 27 Pages, 2021/06
Chemical Processing Facility (CPF) of Japan Atomic Energy Agency (JAEA) has been developing the fast reactor fuel reprocessing and vitrification technology. The various kinds of radioactive liquid wastes, which were generated by those experiments and analysis, stored in the hot cells and glove boxes of CPF. The treatment of radioactive liquid wastes were started since July 2015; however, treatment of several kinds of liquid wastes are revealed to be difficult due to contain the various hazardous chemicals. Therefore, in order to establish the new technology suitable for radioactive liquid waste treatment, several collaborative research programs with several universities and national research organizations were started. The combined project lead by JAEA was named to be STRAD (Systematic Treatments of Radioactive liquid wastes for Decommissioning) project. In this project, the process flow for treatment of several actual liquid wastes were established. In this report, treated method and progress of actual liquid wastes of CPF are summarized.
Miyazaki, Yasunori; Watanabe, So; Nakamura, Masahiro; Shibata, Atsuhiro; Nomura, Kazunori; Kai, Tetsuya; Parker, J. D.*
JPS Conference Proceedings (Internet), 33, p.011073_1 - 011073_7, 2021/03
Neutron resonance absorption imaging was adapted to observe the Eu band adsorbed in the CMPO/SiO-P column for minor actinide recovery by extraction chromatography. Several wet columns were prepared by either light water or heavy water and compared with the dry column to evaluate the neutron transmission. The neutron transmission spectra showed that 45% was transmitted through the dry column while 20% and 40% were transmitted through the wet columns of light water and heavy water, respectively. The results indicated that heavy water is more applicable than light water to observe the Eu adsorption band in the CMPO/SiO
-P column.
Shibata, Takanori*; Ikegami, Kiyoshi*; Nammo, Kesao*; Liu, Y.*; Otani, Masashi*; Naito, Fujio*; Shinto, Katsuhiro; Okoshi, Kiyonori; Okabe, Kota; Kondo, Yasuhiro; et al.
JPS Conference Proceedings (Internet), 33, p.011010_1 - 011010_6, 2021/03
Together with the intensity upgrade in J-PARC Linac Front-End, improvement of RFQ transmission ratio is an important task. This RFQ transmission ratio depends strongly upon the solenoid current settings in the low energy beam transport line (LEBT). In the present study, high beam current cases (72 mA and 88 mA H beam current in LEBT) are investigated at a test-stand. Phase space distributions of the H
beam particles at the RFQ entrance are measured and compared with numerical results by Particle-In-Cell simulation. As a result, it has been clarified that a 15 mm
orifice for differential pumping of H
gas coming from the ion source plays a role as a collimator in these beam conditions. This leads to change the beam emittance and Twiss parameters at the RFQ entrance. Especially in the condition with the beam current up to 88 mA in LEBT, the beam collimation contributes to optimize the phase space distribution to the RFQ acceptance with relatively low solenoid current settings. As a higher solenoid current setting would be necessary to suppress the beam expansion due to high space charge effect, these results suggest that current-saving of the solenoids can be possible even in the higher beam intensity operations.
Okabe, Kota; Liu, Y.*; Otani, Masashi*; Moriya, Katsuhiro; Shibata, Takanori*; Chimura, Motoki*; Hirano, Koichiro; Oguri, Hidetomo; Kinsho, Michikazu
JPS Conference Proceedings (Internet), 33, p.011011_1 - 011011_6, 2021/03
To realize more stable operation of the J-PARC accelerators, we have a re-design plan of an MEBT1 (Medium Energy Beam Transport). At the J-PARC Linac, the MEBT1 has transverse and longitudinal beam matching section for the DTLs. However there are some locally activated spots in DTL area at the current beam power level. To reduce beam loss during a beam acceleration at the DTLs is a most important task for a stable user operation. The first thing we should do is investigation a connection between beam quality in the MEBT1 and parameters of the upstream hardware. In this presentation, we will report a high intensity beam study results at the MEBT1.
Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.
Proceedings of International Waste Management Symposia 2021 (WM 2021) (CD-ROM), 10 Pages, 2021/03
Wada, Motoi*; Shinto, Katsuhiro; Shibata, Takanori*; Sasao, Mamiko*
Review of Scientific Instruments, 91(1), p.013330_1 - 013330_5, 2020/01
Times Cited Count:0 Percentile:0(Instruments & Instrumentation)The ions are extracted from an ion source through a plasma sheath where a low frequency electromagnetic induction drives transport of charged particles including the target ions. High frequency alternating current commonly excites plasmas in sources for negative hydrogen (H) ions at a frequency in the MHz range. A high-speed beam current monitor system coupled to a narrow entrance slit enabled the investigation of the special distribution of the AC component intensity of the H
ion beam extracted from an ion source driven by a 2 MHz radio frequency (RF) power. The distribution showed a smaller oscillation of the beam at the center.
Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.
Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12
Times Cited Count:0 Percentile:0.07We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.
Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Takeuchi, Masayuki; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Horiuchi, Yusuke*; Arai, Tsuyoshi*
Journal of Radioanalytical and Nuclear Chemistry, 322(3), p.1273 - 1277, 2019/12
Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)Watanabe, So; Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Takahatake, Yoko; Shibata, Atsuhiro; Nomura, Kazunori; Kamiya, Yuichi*; Asanuma, Noriko*; Matsuura, Haruaki*; et al.
Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11
Times Cited Count:6 Percentile:75.46(Nuclear Science & Technology)Nakahara, Masaumi; Watanabe, So; Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Motoyama, Risa; Shibata, Atsuhiro; Nomura, Kazunori; Kajinami, Akihiko*
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.66 - 70, 2019/09
A wide variety of hazardous and radioactive liquid waste has generated derived from an advanced aqueous separation experiments in the Chemical Processing Facility. Therefore, they should be stabilized for the safety handling and management. In this study, we report a precipitation or an oxidation for hazardous materials, a solvent extraction for recovery of nuclear materials, and a concentration of solution by a freeze-drying method.
Nakahara, Masaumi; Watanabe, So; Ogi, Hiromichi*; Shibata, Atsuhiro; Nomura, Kazunori
International Journal of Nuclear and Quantum Engineering (Internet), 13(4), p.191 - 194, 2019/04
High level radioactive solid waste is reduced the volume or stabilized in the Chemical Processing Facility in the Japan Atomic Energy Agency. A plastic product is molten with a heating mantle and reduced the volume. A non-flammable such as metal is cut with a band saw machine for reducing the volume. A used adsorbent in the extraction chromatograph process was heated with an electric furnace using non-radioactive materials, and the experimental result suggests that organic materials in the used adsorbent were decomposed stably.
Watanabe, So; Ogi, Hiromichi*; Shibata, Atsuhiro; Nomura, Kazunori
International Journal of Nuclear and Quantum Engineering (Internet), 13(4), p.169 - 174, 2019/04
As a part of STRAD project conducted by JAEA, condensation of radioactive liquid waste containing various chemical compounds using reverse osmosis (RO) membrane filter was examined for efficient and safety treatment of the liquid wastes accumulated inside hot laboratories. NH ion in the feed solution was successfully concentrated, and NH
ion involved in the effluents became lower than target value; 100 ppm. Solidification of simulated aqueous and organic liquid wastes was also tested. Those liquids were successfully solidified by adding cement or coagulants. Nevertheless, optimization in materials for confinement of chemicals is required for long time storage of the final solidified wastes.