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Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Aoyagi, Katsuhiro*; Muto, Hideki*; Nomura, Kazutaka*; Takada, Hiroshi; Ikeda, Yujiro
JAEA-Technology 2017-021, 75 Pages, 2017/08
JAEA-Technology-2017-021.pdf:33.03MB
Liquid hydrogen is employed as a cold neutron moderator material at the spallation neutron source of Materials and Life science experimental Facility of Japan Proton Accelerator Research Complex (J-PARC). From January 2015, it became observable that the differential pressure between heat exchangers and an 80 K adsorber (ADS) in a helium refrigerator system increased with operating time. In November 2015, the differential pressure rise became more significant, leading to degrade the refrigerating performance in cooling liquid hydrogen. In order to investigate the cause of the abnormal differential pressure rise between the heat exchangers and the ADS, we carried out visual inspection inside the heat exchangers and analyzed the impurities contained in the helium gas. Unfortunately, we could not identify the impurities causing the performance degradation, but observed a trace of oil in the inlet piping of the heat exchanger. Based on investigations of the abnormal events occurred in the refrigerators with similar refrigerating capacity at other facilities, we took measures that cleaning the heat exchangers with Freon and replacing the ADS with new one. As a result, the differential pressure rise phenomenon was removed to recover the performance. We have detected oil from the Freon used for cleaning the heat exchangers and at a felt supporting charcoal packed in the ADS. In particular, oil was accumulated in membranous form onto the felt at the entrance side in the ADS. The amount of oil contained in the helium gas was about 10 ppb or so, less than the design value, in the helium refrigerator. However, the oil accumulated onto the felt in the ADS through long operating period may cause abnormal differential pressure rise, leading to the performance degradation of the helium refrigerator. Further study is needed to specify the cause more clearly.
Ebisawa, Noboru; Kiuchi, Shigeki*; Kikuchi, Katsumi*; Kawano, Katsumi; Isono, Takaaki
JAEA-Testing 2014-003, 37 Pages, 2015/03
JAEA-Testing-2014-003.pdf:11.7MB
Objective of the ITER CS Model Coil Test Facility is to evaluate a large scale superconducting conductor for fusion using the Central Solenoid (CS) Model Coil, which can generate a 13-T magnetic field in the inner bore with a 1.5m diameter. The facility is composed of a helium refrigerator / liquefier system, a DC power supply system, a vacuum system and a data acquisition system. This report describes that maintenance of the helium refrigerator / liquefier system since the Great East Japan Earthquake in March 2011 until the first operation after the earthquake in December 2012.
Aso, Tomokazu; Tatsumoto, Hideki; Hasegawa, Shoichi; Ushijima, Isamu*; Otsu, Kiichi*; Kato, Takashi; Ikeda, Yujiro
AIP Conference Proceedings 823, p.763 - 770, 2006/05
no abstracts in English
Seki, Hiroshi*; Oga, Tokumichi; Akino, Noboru; Tanai, Yutaka*; *; Kuriyama, Masaaki; Ito, Takao; *
KEK Proceedings 99-17 (CD-ROM), 4 Pages, 1999/00
no abstracts in English
; Shibata, Michihiro; Ishii, Tetsuro;
Proc. of the 9th Symp. on Accelerator Science and Technology, p.437 - 439, 1993/00
no abstracts in English
DESY-M-92-01 (Vol. 1), p.76 - 83, 1992/04
no abstracts in English
Shibanuma, Kiyoshi; ; Dairaku, Masayuki; *; Matsuda, Shinzaburo; Ouchi, Yutaka; *; Shibata, Takemasa
Nihon Genshiryoku Gakkai-Shi, 33(12), p.1171 - 1179, 1991/12
Times Cited Count：1 Percentile：19.9(Nuclear Science & Technology)no abstracts in English
Shibanuma, Kiyoshi; ; Dairaku, Masayuki; Ouchi, Yutaka; Shibata, Takemasa
JAERI-M 91-180, 39 Pages, 1991/10
no abstracts in English
Shibanuma, Kiyoshi; ; Dairaku, Masayuki; Kunieda, Shunsuke; Kuriyama, Masaaki; Matsuda, Shinzaburo; Ouchi, Yutaka; Shibata, Takemasa; Shirakata, Hirofumi
Nihon Genshiryoku Gakkai-Shi, 33(10), p.960 - 974, 1991/10
Times Cited Count：1 Percentile：19.9(Nuclear Science & Technology)no abstracts in English
Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi
no journal, ,
no abstracts in English
Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi
no journal, ,
no abstracts in English
Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi; Ikeda, Yujiro
no journal, ,
no abstracts in English
Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi; Ikeda, Yujiro
no journal, ,
no abstracts in English
Teshigawara, Makoto; Aso, Tomokazu; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi; Ikeda, Yujiro
no journal, ,
Performance degradation of helium refrigerator was occurred for liquid hydrogen circulation system of J-PARC high intensity neutron source since 2015. In order to find the cause of performance degradation of helium refrigerator, we investigated the impurities in helium gas and accumulated oil in inside cold box components by quadrupole mass spectrometer and organic solvent extraction. The measured impurities and accumulated oil were less than design value. We collected 143g of total amount of accumulated oil from heat exchanger and adosorber, which was corresponded to estimated value from 10 ppb of oil contamination in helium and accumulated operation period. However, we only could find out that accumulated oil like coating film on top surface of felt, which was used to hold the active charcoal in adsorber. We report detailed measurement results of impurities, accumulated oil, etc., to find the cause of performance degradation.
Aso, Tomokazu; Teshigawara, Makoto; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi
no journal, ,
Liquid hydrogen (20 K, 1.4 MPaG) is employed as a cold neutron moderator material at the 1 MW spallation neutron source of Japan Proton Accelerator Research Complex (J-PARC). The cryogenic hydrogen system, combined with a helium refrigerator, was adopted to generate a liquid hydrogen circulation flow (185 g/s). Since January 2015, a pressure drop gradually increased between heat exchangers HXs) and an adsorber (ADS) in the helium refrigerator for each operation, causing the refrigerator performance degradation. The performance of helium refrigerator could be recovered as a result of countermeasures focused on accumulated oil removal, such as cleaning the inside HXs and exchanging the ADS at 2016 summer shutdown, however the detailed cause is still in doubt. On the other hand, a long run stable operation could be secured over 175 days in 2018. Just end of long run operation, a first high-intensity-beam injection with 1MW beam power was also carried out for one hour aiming to confirm the refrigerator performance according to design requirement.
