Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 21

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

JAEA Reports

Improvement of accumulator in cryogenic hydrogen system used for 1-MW pulsed spallation neutron source

Aso, Tomokazu; Tatsumoto, Hideki*; Otsu, Kiichi*; Kawakami, Yoshihiko*; Komori, Shinji*; Muto, Hideki*; Takada, Hiroshi

JAEA-Technology 2019-013, 77 Pages, 2019/09

JAEA-Technology-2019-013.pdf:5.59MB

At Materials and Life Science experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), a 1-MW pulsed spallation neutron source is equipped with a cryogenic hydrogen system which circulates liquid hydrogen (20 K and 1.5 MPa) to convert high energy neutrons generated at a mercury target to cold neutrons at three moderators with removing nuclear heat of 3.8 kW deposited there. The cryogenic system includes an accumulator with a bellows structure in order to absorb pressure fluctuations generated by the nuclear heat deposition in the system. Welded inner bellows of the first accumulator was failured during operation, forcing us to improve the accumulator to have sufficient pressure resistance and longer life-time. We have developed elemental technologies for manufacturing welded bellows of the accumulator by a thick plate with high pressure resistance, succeeding to find optimum welding conditions. We fabricated a prototype bellows block and carried out an endurance test by adding a pressure change of 2 MPa repeatedly. As a result, the prototype bellows was successfully in use exceeding the design life of 10,000 times. Since distortions given during welding and assembling affect functionality and lifetime of the bellows, we set the levelness of each element of the bellows as within 0.1$$^{circ}$$. The improved accumulator has already been in operation for about 25,000 hours as of January 2019, resulting that the number of strokes reached to 16,000. In July 2018, we demonstrated that the accumulator could suppress the pressure fluctuation generated by the 932 kW beam injection as designed. As current operational beam power is 500 kW, the current cryogenic hydrogen system could be applicable for stable operation at higher power in the future.

Journal Articles

Post irradiation experiment about SiC-coated oxidation-resistant graphite for high temperature gas-cooled reactor

Shibata, Taiju; Mizuta, Naoki; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; et al.

Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10

Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR). Oxidation damage on the graphite components in air ingress accident is a crucial issue for the safety point of view. SiC coating on graphite surface is a possible technique to enhance oxidation resistance. However, it is important to confirm the integrity of this material against high temperature and neutron irradiation for the application of the in-core components. JAEA and Japanese graphite companies carried out the R&D to develop the oxidation-resistant graphite. JAEA and INP investigated the irradiation effects on the oxidation-resistant graphite by using a framework of ISTC partner project. This paper describes the results of post irradiation experiment about the neutron irradiated SiC-coated oxidation-resistant graphite. A brand of oxidation-resistant graphite shows excellent performance against oxidation test after the irradiation.

Journal Articles

Enhancement of oxidation tolerance of graphite materials for high temperature gas-cooled reactor

Mizuta, Naoki; Sumita, Junya; Shibata, Taiju; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Sakaba, Nariaki

Tanso Zairyo Kagaku No Shinten; Nihon Gakutsu Shinkokai Dai-117-Iinkai 70-Shunen Kinen-Shi, p.161 - 166, 2018/10

To enhance oxidation resistance of graphite material for in-core components of HTGR, JAEA and four Japanese graphite companies; Toyo Tanso, IBIDEN, Tokai Carbon and Nippon Techno-Carbon, are carrying out for development of oxidation-resistant graphite by CVD-SiC coating. This paper describes the outline of neutron irradiation test about the oxidation-resistant graphite by WWR-K reactor of INP, Kazakhstan through an ISTC partner project. Prior to the irradiation test, the oxidation-resistant graphite by CVD-SiC coating of all specimens showed enough oxidation resistance under un-irradiation condition. The neutron irradiation test was already completed and out-of-pile oxidation test will be carried out at the hot-laboratory of WWR-K.

Journal Articles

Recovery of helium refrigerator performance for cryogenic hydrogen system at J-PARC MLF

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi

Journal of Physics; Conference Series, 1021(1), p.012085_1 - 012085_4, 2018/06

JAEA Reports

Investigation and measures of abnormal events of helium refrigerator for cryogenic hydrogen system at J-PARC

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.

Journal Articles

Irradiation test about oxidation-resistant graphite in WWR-K research reactor

Shibata, Taiju; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; Dyussambayev, D.*; et al.

Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.567 - 571, 2016/11

Graphite are used for the in-core components of HTGR, and it is desirable to enhance oxidation resistance to keep much safety margin. SiC coating is the candidate method for this purpose. JAEA and four Japanese graphite companies are studying to develop oxidation-resistant graphite. Neutron irradiation test was carried out by WWR-K reactor of INP of Kazakhstan through ISTC partner project. The total irradiation cycles of WWR-K operation was 10 cycles by 200 days. Irradiation temperature about 1473 K would be attained. The maximum fast neutron fluence (E $$>$$0.18 MeV) for the capsule irradiated at a central irradiation hole was preliminary calculated as 1.2$$times$$10$$^{25}$$/m$$^{-2}$$, and for the capsule at a peripheral irradiation hole as 4.2$$times$$10$$^{24}$$/m$$^{-2}$$. Dimension and weight of the irradiated specimens were measured, and outer surface of the specimens were observed by optical microscope. For the irradiated oxidation resistant graphite, out-of-pile oxidation test will be carried out at an experimental laboratory.

Journal Articles

Irradiation test plan of oxidation-resistant graphite in WWR-K research reactor

Sumita, Junya; Shibata, Taiju; Sakaba, Nariaki; Osaki, Hiroki*; Kato, Hideki*; Fujitsuka, Kunihiro*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; Dyussambayev, D.*; et al.

Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 7 Pages, 2014/10

Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor(HTGR)which is a graphite-moderated and helium gas-cooled reactor. In the case of air ingress accident in HTGR, SiO$$_{2}$$ protective layer is formed on the surface of SiC layer in TRISO CFP and oxidation of SiC does not proceed and fission products are retained inside the fuel particle. A new safety concept for the HTGR, called Naturally Safe HTGR, has been recently proposed. To enhance the safety of Naturally Safe HTGR ultimately, it is expected that oxidation-resistant graphite is used for graphite components to prevent the TRISO CFPs and fuel compacts from failure. SiC coating is one of candidate methods for oxidation-resistant graphite. JAEA and four graphite companies launched R&Ds to develop the oxidation-resistant graphite and the International Science and Technology Center(ISTC) partner project with JAEA and INP was launched to investigate the irradiation effects on the oxidation-resistant graphite. To determine grades of the oxidation-resistant graphite which will be adopted as irradiation test, a preliminary oxidation test was carried out. This paper described the results of the preliminary oxidation test, the plan of out-of-pile test, irradiation test and post-irradiation test(PIE)of the oxidation-resistant graphite.

Journal Articles

Development of multi-purpose MW gyrotrons for fusion devices

Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.

Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06

Journal Articles

Development of multi-purpose MW gyrotrons for fusion devices

Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.

Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06

 Times Cited Count:12 Percentile:41.71(Physics, Fluids & Plasmas)

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

Control of thermal load on the JT-60 NBI power supply system for 30 second operation

Oshima, Katsumi*; Honda, Atsushi; Okano, Fuminori; Usui, Katsutomi; Noto, Katsuya*; Muto, Hideki*; Kawai, Mikito; Oga, Tokumichi; Ikeda, Yoshitaka

Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03

no abstracts in English

Oral presentation

Collaboration with Republic of Kazakhstan regarding development of HTGR, 3; Collaboration of development of oxidation-resistant graphite material for HTGR

Shibata, Taiju; Sumita, Junya; Nagata, Hiroshi; Saito, Takashi; Tsuchiya, Kunihiko; Sakaba, Nariaki; Osaki, Hiroki*; Kato, Hideki*; Fujitsuka, Kunihiro*; Muto, Takenori*; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of 3rd accumulator for cryogenic hydrogen system at MLF

Aso, Tomokazu; Tatsumoto, Hideki; Otsu, Kiichi; Kawakami, Yoshihiko; Komori, Shinji; Muto, Hideki; Takada, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Efforts to recover performance of helium refrigerator for cryogenic hydrogen system at MLF

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Recovery of helium refrigerator performance for hydrogen moderator of spallation neutron source at MLF

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Performance degradation of helium refrigerator for liquid hydrogen circulation system of J-PARC high intensity neutron source; Over view of performance degradation

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi; Ikeda, Yujiro

no journal, , 

no abstracts in English

Oral presentation

Performance degradation of helium refrigerator for liquid hydrogen circulation system of J-PARC high intensity neutron source; Key points to performance recover and future plan

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi; Ikeda, Yujiro

no journal, , 

no abstracts in English

Oral presentation

Performance degradation of helium refrigerator for liquid hydrogen circulation system of J-PARC high intensity neutron source; Investigation of performance degradation

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.

Oral presentation

Performance degradation of helium refrigerator for liquid hydrogen circulation system of J-PARC high intensity neutron source; Element test related to increasing differential pressure, which might cause performance degradation

Teshigawara, Makoto; Aso, Tomokazu; 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. During cause investigation of performance degradation of helium refrigerator, we found out that accumulated oil like coating film on top surface of felt, which was used to hold the active charcoal in adsorber, might cause pressure difference in adsorber. We performed cold nitrogen gas flow test in the felt accumulated oil and found out that frozen oil under cold nitrogen flow caused the pressure difference.

Oral presentation

Performance degradation of helium refrigerator for cryogenic hydrogen system at J-PARC

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki*; Aoyagi, Katsuhiro*; Takada, Hiroshi

no journal, , 

Oral presentation

Present status and test result of 1MW proton beam injection of liquid hydrogen circulation system of J-PARC high intensity neutron source

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.

21 (Records 1-20 displayed on this page)