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Sato, Hinata; Mori, Amami; Kuno, Sorato; Horigome, Kazushi; Goto, Yuichi; Yamamoto, Masahiko; Taguchi, Shigeo
JAEA-Technology 2024-011, 56 Pages, 2024/10
JAEA-Technology-2024-011.pdf:2.5MB
Flush-out, which recovers remaining nuclear materials in the process and transfer it to a highly radioactive liquid waste storage tank, has been performed at main plant of Tokai Reprocessing Plant. The flush-out has been composed from three steps: first step is to remove of spent fuel sheared powder, second step is to collect plutonium solution stored in the process, and third step is to convert uranium solution into uranium trioxide powder. The first step of flush-out activity has been completed in 2022. Second and third steps of flush-out have been completed from March 2023 to February 2024. Process control analysis has been performed for operation of the facility, and material accountancy analysis has been performed to control the accountancy of nuclear materials. In addition, related analytical work such as pretreatment for transporting inspection samples for safeguards analysis laboratories in IAEA has been also performed. This report describes results of analytical work performed in collections of plutonium and uranium solutions in second and third steps of the flush-out, including calibration of analytical equipment, waste generation, and education and training of analytical operator.
Aoya, Juri; Mori, Amami; Sato, Hinata; Kono, Soma; Morokado, Shiori; Horigome, Kazushi; Goto, Yuichi; Yamamoto, Masahiko; Taguchi, Shigeo
JAEA-Technology 2023-008, 34 Pages, 2023/06
JAEA-Technology-2023-008.pdf:1.92MB
Flush-out, by which nuclear materials in the Tokai Reprocessing Plant process are recovered, has been started in June 2022 as the first step of decommissioning. Flush-out consists of removal of spent fuel sheared powder, plutonium solution, uranium solution, and the other nuclear materials. Removal of spent fuel sheared powder has been completed in September 2022. During removal of spent fuel sheared powder, uranium concentration, plutonium concentration, acid concentration, radioactivity concentration, and solution density have been analyzed for process control. For nuclear material accountancy, uranium concentration, plutonium concentration, isotope ratio, and solution density have been analyzed. Analysis work including sample pretreatment before transportation to IAEA analytical facility for safeguards, and the other operations related to Flush-out such as calibration of analytical instruments, education, and training of operators are reported.
Kobayashi, Takayuki; Moriyama, Shinichi; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Hoshino, Katsumichi; et al.
Nuclear Fusion, 55(6), p.063008_1 - 063008_8, 2015/06
Times Cited Count：27 Percentile：76.24(Physics, Fluids & Plasmas)A gyrotron enabling high-power, long-pulse oscillations at both 110 GHz and 138 GHz has been developed for electron cyclotron heating (ECH) and current drive (CD) in JT-60SA. Oscillations of 1 MW for 100 s have been demonstrated at both frequencies, for the first time as a gyrotron operating at two frequencies. The optimization of the anode voltage, or the electron pitch factor, using a triode gun was a key to obtain high power and high efficiency at two frequencies. It was also confirmed that the internal losses in the gyrotron were sufficiently low for expected long pulse operation at the higher power level of 
1.5 MW. Another important result is that an oscillation at 82 GHz, which enables to use fundamental harmonic waves in JT-60SA while the other two frequencies are used as second harmonics waves, was demonstrated up to 0.4 MW for 2 s. These results of the gyrotron development significantly contribute to enhancing operation regime of the ECH/CD system in JT-60SA.
Kobayashi, Takayuki; Moriyama, Shinichi; Isayama, Akihiko; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; et al.
EPJ Web of Conferences, 87, p.04008_1 - 04008_5, 2015/03
Times Cited Count：5 Percentile：81.93(Physics, Fluids & Plasmas)A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Operation for the gyrotron conditioning and parameter optimization toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without problems. Oscillations of 1 MW for 10 s and 0.51 MW for 198 s were obtained, so far, at both frequencies. In addition, an oscillation (0.3 MW for 20 ms) at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron which shows a possibility of the use of fundamental harmonic wave in JT-60SA.
Yokokura, Kenji; Moriyama, Shinichi; Kobayashi, Takayuki; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Hinata, Jun; Wada, Kenji; Sato, Yoshikatsu; Hoshino, Katsumichi; et al.
JAEA-Technology 2014-002, 64 Pages, 2014/03
JAEA-Technology-2014-002.pdf:6.83MB
A new instrument has been developed to measure spatial distribution of power density and total power of the millimeter wave, by measuring temperature rise of dielectric material inserted in the waveguide. For a measurement, a dielectric disk with thermally insulated support is inserted into the few millimeters gap in the waveguide. The disk is heated by the millimeter wave pulse for 0.10.2 s, and immediately after the pulse, it is pulled up and its temperature distribution is measured by an infrared camera to estimate the spatial power density distribution of the millimeter wave. In the other hand, total transmission power is estimated by the disk temperature reached equilibrium. In the measurement test, deformation of the power density distribution was successfully detected when the mirror angle was intentionally changed in the matching optics unit (MOU) at the waveguide input from the gyrotron. The test result shows that the instrument is effective for both adjustment of MOU without opening the vacuum boundary and to detect any abnormal transmission during operation of the ECH system. The test also shows high reliability of the instrument which stands with 1 MW high power transmission without any arcing or pressure rise in vacuum region. The instrument will be contributed to keep good condition of high power long pulse ECH system by detecting abnormal transmission in the waveguide in operation without open vacuum boundary.
Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Hoshino, Katsumichi; Suzuki, Sadaaki; Hiranai, Shinichi; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hinata, Jun; et al.
Fusion Engineering and Design, 88(6-8), p.935 - 939, 2013/10
Times Cited Count：4 Percentile：30.44(Nuclear Science & Technology)An antenna having a first mirror driven in the linear motion (LM) and a fixed second mirror was proposed for electron cyclotron range of frequency (ECRF) heating and current drive system, to minimize the risk of cooling-water-leakage. Basic mechanical feasibilities of the bellows covering the movable structures of the antenna were previously investigated using a mock-up. This time, a support structure of the shaft has been designed using a metallic sliding bearing with solid lubricant. The sliding bearing can support combination of linear and rotational motions while a ball bearing supports either linear or rotational motion. We have newly installed the sliding bearing into the mock-up. A vacuum pumping test has been carried out paying attention to the influence of the solid lubricant by mass analysis. To design the LM antenna for JT-60SA in detail, heating and current drive characteristics for typical experimental scenarios of JT-60SA has been investigated by calculation.
Kobayashi, Takayuki; Isayama, Akihiko; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; et al.
Fusion Science and Technology, 63(1T), p.160 - 163, 2013/05
Times Cited Count：8 Percentile：50.48(Nuclear Science & Technology)A dual frequency electron cyclotron range of frequency system has been developed for JT-60SA, by which a second frequency (135 140 GHz) is generated in addition to the first frequency of 110 GHz. A development of a dual frequency gyrotron is a key to realize the dual frequency system. The second frequency was chosen to be 138 GHz from the above frequency range from the viewpoint of gyrotron design. In order to realize high-power (
1 MW) and long-pulse operation for both frequencies, we designed main components of the gyrotron (the diamond window, cavity resonator and quasi-optical mode converter). We found the optimum parameter set from the parameters of these components, which has discrete characteristics. It was confirmed that the output power higher than 1 MW is obtained for both frequencies as a result of numerical design. Based on the above design, a dual frequency gyrotron was newly fabricated. In the conditioning operation, an output power was obtained as we expected.
Kobayashi, Takayuki; Isayama, Akihiko; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; et al.
Proceedings of 37th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2012) (USB Flash Drive), 2 Pages, 2012/09
A new dual frequency (110 GHz and 138 GHz) gyrotron development began for JT-60SA. An output power and efficiency higher than 1 MW and 30% with a peak heat load lower than 1.4 kW/cm
were obtained for both frequencies in calculation. High mode conversion efficiencies of the quasioptical mode converter (96.8% for 110 GHz and 98.3% for 138 GHz), which is higher than the previously developed 110 GHz long pulse gyrotron (96.5%), was obtained. The new gyrotron was fabricated and conditioning operation has been started from the middle of June 2012. The gyrotron output power of approximately 200 kW was obtained, so far, as we expected in the design of the gyrotron at low beam current of 10 A and low beam voltage of 75 kV.
Isayama, Akihiko; Kobayashi, Takayuki; Yokokura, Kenji; Shimono, Mitsugu; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Hinata, Jun; et al.
Plasma and Fusion Research (Internet), 7(Sp.1), p.2405029_1 - 2405029_5, 2012/05
no abstracts in English
Kobayashi, Takayuki; Isayama, Akihiko; Hasegawa, Koichi; Suzuki, Sadaaki; Hiranai, Shinichi; Sato, Fumiaki; Wada, Kenji; Yokokura, Kenji; Shimono, Mitsugu; Sawahata, Masayuki; et al.
Fusion Engineering and Design, 86(6-8), p.763 - 767, 2011/10
Times Cited Count：6 Percentile：42.22(Nuclear Science & Technology)Progress of antenna development of the Electron Cyclotron Range of Frequency system for JT-60 SA is presented. Capability of pulse length of 100 s, which requires active cooling for mirrors, and flexibility of beam injection angles in both poloidal and toroidal directions are required for the antenna with high reliability. Mechanical and structural design works of the launcher (antenna and its support with steering structure) based on a linear motion antenna concept are in progress. The key component is a long-stroke bellows which enables to alter poloidal injection angle and a bellows which enables to alter toroidal injection angle. Using a newly fabricated mock-up of the steering structure, it was confirmed that the antenna was mechanically realized for poloidal and toroidal injection angle ranges of -10 to +45
and -15 to +15, respectively. Those angles are consistent with angles required in JT-60SA. The results of thermal and structural analyses are also presented.
Kobayashi, Takayuki; Isayama, Akihiko; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Sato, Fumiaki; et al.
Nuclear Fusion, 51(10), p.103037_1 - 103037_10, 2011/10
Times Cited Count：20 Percentile：61.96(Physics, Fluids & Plasmas)A new gyrotron operation technique to increase oscillation efficiency was developed on the JT 60 ECRF system. The electron pitch factor was optimized by controlling anode voltage within 0.1 s after the start of the operation. By applying this technique, the gyrotron output power of 1.5 MW for 4 s was recorded, for the first time. The reduced collector heat load at 1.5 MW operations was reduced by 20% and it will be acceptable for longer pulse operation. A new gyrotron with an improved mode converter was developed in order to demonstrate reduction of the stray radiation which had limited the pulse length. The stray radiation was reduced to 1/3 of that of the original gyrotron. A conditioning operation of the improved gyrotron is proceeding up to 31 s at 1 MW. These progresses significantly contribute to enhancing the high power and long pulse capability of the ECRF system toward JT 60SA.
Kobayashi, Takayuki; Isayama, Akihiko; Fasel, D.*; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.363 - 368, 2010/08
Improvements are required for expanding the pulse length of the JT-60 ECRF system (5s) for JT-60SA (100s). Newly developed power supplies will be fabricated and installed by EU. The conditioning operation of an improved gyrotron equipping a newly designed mode convertor has been started. The mode convertor will reduce heat flux on the internal components and therefore expected to enable long pulse operation at 1 MW. Pre-programmed and/or feedback control of the heater current and anode voltage, which was successfully demonstrated in JT-60U, will be key techniques because the beam current decreases during a shot. The evacuated transmission lines have a capability of 1 MW per line. Since maintenance of the components in the vacuum vessel is difficult, a linear motion antenna concept was proposed to reduce risks of water leakage and fault of the driving mechanism in the vacuum vessel. The detailed design and the low power test of a mock-up antenna have been started.
Kobayashi, Takayuki; Isayama, Akihiko; Hoshino, Katsumichi; Yokokura, Kenji; Shimono, Mitsugu; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; et al.
no journal, ,
Design and development of high-power long-pulse electron cyclotron heating and current drive system for JT-60SA have been progressed. High power transmission test using newly developed components with a waveguide inner diameter of 60.3 mm was carried out. A conditioning operation was progressed to 5 s with an output power of 0.5 MW, so far, within a few weeks without significant trouble. The other progress was made to develop the dual frequency system with an additional frequency of 137.6 GHz in order to enhance operation regime. Output power higher than 1 MW with oscillation efficiency much higher than 30% was obtained for the design of a dual frequency gyrotron for both 110 GHz and 137.6 GHz.
Wada, Kenji; Kobayashi, Takayuki; Isayama, Akihiko; Hasegawa, Koichi; Sato, Fumiaki; Yokokura, Kenji; Suzuki, Sadaaki; Shibayama, Minoru; Hiranai, Shinichi; Shimono, Mitsugu; et al.
no journal, ,
no abstracts in English
Moriyama, Shinichi; Isayama, Akihiko; Kobayashi, Takayuki; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Hasegawa, Koichi; Shimono, Mitsugu; Yokokura, Kenji; et al.
no journal, ,
no abstracts in English
Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; et al.
no journal, ,
The electron cyclotron range of frequency (ECRF) system (3 MW 
5s at 110 GHz with 4 gyrotrons) of JT-60U will be upgrade to the system having 9 gyrotrons (7 MW 100s) for JT-60SA (super advanced). As heat removal from the mirrors is essential for a long pulse antenna, a new concept with a mirror driven in the linear motion which eliminates the flexible tube for coolant supply is under development. The design study featuring beam profile calculation showed feasibility of the antenna in the 0.48 m 0.48 m port. The low power rf test with simple mockup antenna has just been begun. Aging of the gyrotron with improved mode converter was started in the end of 2008, aiming at 1 MW, 100s oscillation. Because the current capacity of the present high voltage power supply is not enough to realize 100s oscillation, LHRF power supply having twice larger current capacity is connected to the gyrotron in March 2009. The gyrotron aging will be started soon again.
Hiranai, Shinichi; Yokokura, Kenji; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hinata, Jun; Wada, Kenji; Sato, Yoshikatsu; Hoshino, Katsumichi; Moriyama, Shinichi
no journal, ,
no abstracts in English
Moriyama, Shinichi; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
Long pulse operation of the dual frequency gyrotron was started for JT-60SA ECH system. Pulse length of 2 s at 0.4 MW output, and 1 s at 0.7 MW were obtained at both 110 GHz and 138 GHz, so far. Typical oscillation efficiency is about 30%. Diffraction loss was acceptable for long pulse 1 MW output. The first high power test of the "power and beam profile monitor" featuring a fast movable Si
N
disk in the waveguide slit was successfully demonstrated.
Kobayashi, Takayuki; Isayama, Akihiko; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
An original design of the toroidal injection angle range of electron cyclotron waves in JT-60SA was -15 degree to +15 degree for effective use of 110 GHz wave. However, the modification of the toroidal angle range has been discussed since the frequency of 138 GHz is considered to be a second frequency by the use of a dual frequency gyrotron. We report newly calculated available steering range of the launcher on both poloidal and toroidal angles with and without tilting angle of the second mirror, which is considered to obtain large toroidal injection angle. Moreover calculated beam divergences for various curvature radiuses of the first and second mirrors are shown. The decision of the target injection angle range for JT-60SA initial plasma will be made by the JT-60SA physics team by taking into account the above calculation results.
Kobayashi, Takayuki; Isayama, Akihiko; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Hoshino, Katsumichi; et al.
no journal, ,
Development of high-power, long-pulse electron cyclotron range of frequency heating system for JT-60SA is in progress. A dual frequency gyrotron was developed in order to extend operation regime of the system. Short pulse oscillations at 110 GHz and 138 GHz were obtained up to 1 MW and 0.5 MW, respectively. Observed power, efficiency, frequency and beam location at the output window were consistent with the design. Long pulse operations of a 110 GHz gyrotron with a large diameter waveguide transmission line at 1 MW were also carried out. Pulse duration of 70 s, which was twice longer than the previous record, was obtained. High power operation of 1.4 MW for 9 s was also obtained by applying a high efficiency operation technique. Progress in research and developments of transmission line components and antenna for enabling dual frequency operation is also presented.
