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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

Cryogenic sample environments shared at the MLF, J-PARC

Kawamura, Seiko; Takahashi, Ryuta*; Ishikado, Motoyuki*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ouchi, Keiichi*; Kira, Hiroshi*; Kambara, Wataru*; Aoyama, Kazuhiro*; Sakaguchi, Yoshifumi*; et al.

Journal of Neutron Research, 21(1-2), p.17 - 22, 2019/05

The Cryogenics and Magnets group in the Sample Environment team is responsible for operation of cryostats and magnets for user's experiments at the MLF in J-PARC. We have introduced a top-loading $$^4$$He cryostat, a bottom-loading $$^3$$He cryostat, a dilution refrigerator insert and a superconducting magnet. The frequency of use of them dramatically becomes higher in these two years, as the beam power and the number of proposal increase. To respond such situation, we have made efforts to enhance performance of these equipment as follows. The $$^3$$He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of $$^3$$He. Recently we made an additional program for automatic temperature control with only the sorb heater. Last year, a new outer vacuum chamber of the magnet with an oscillating radial collimator (ORC) was fabricated. The data quality was drastically improved by introducing this ORC so that the magnet can be used even for the inelastic neutron scattering experiments.

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

BB2016-1899.pdf:0.54MB

Journal Articles

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 1; Pulsed spallation neutron source

Takada, Hiroshi; Haga, Katsuhiro; Teshigawara, Makoto; Aso, Tomokazu; Meigo, Shinichiro; Kogawa, Hiroyuki; Naoe, Takashi; Wakui, Takashi; Oi, Motoki; Harada, Masahide; et al.

Quantum Beam Science (Internet), 1(2), p.8_1 - 8_26, 2017/09

At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width to promote researches on a variety of science in the Materials and life science experimental facility. It was designed to be driven by the proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world's highest power level. A mercury target and three types of liquid para-hydrogen moderators are core components of the spallation neutron source. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this paper, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are reviewed.

Journal Articles

Hydrogen isotope separation by cryogenic distillation

Yamanishi, Toshihiko

Purazuma, Kaku Yugo Gakkai-Shi, 92(1), p.21 - 25, 2016/01

AA2015-0316.pdf:0.93MB

In a fusion reactor, the hydrogen isotope separation system is required in the fuel cycle system to supply deuterium (D) and tritium (T) as its fuel. In ITER, 90% of T must be recycled through the isotope separation system. On the other hand; since the hydrogen (H) gas is finally exhausted to the environment, the T concentration in the H gas from the isotope separation system should be as low as reasonable achievable. Hence, the isotope separation system of a fusion reactor must have a large separation factor. The flow rate of the isotope separation system of a fusion reactor reaches to 300 mol/h. Only the cryogenic distillation method can meet the above conditions (large flow rate and separation factor) and is most likely used as a hydrogen separation system in a fusion reactor. In this chapter, several simulation methods and a set of experimental data of the cryogenic distillation columns are described in detail.

Journal Articles

Thermal strain in superconducting Nb$$_{3}$$Sn strand at cryogenic temperature

Harjo, S.; Kawasaki, Takuro; Hemmi, Tsutomu; Ito, Takayoshi*; Nakamoto, Tatsushi*; Aizawa, Kazuya

JPS Conference Proceedings (Internet), 8, p.031001_1 - 031001_5, 2015/09

Journal Articles

Overview on materials R&D activities in Japan towards ITER construction and operation

Takatsu, Hideyuki; Sato, Kazuyoshi; Hamada, Kazuya; Nakahira, Masataka; Suzuki, Satoshi; Nakajima, Hideo; Kuroda, Toshimasa*; Nishitani, Takeo; Shikama, Tatsuo*; Shu, Wataru

Journal of Nuclear Materials, 329-333(1), p.178 - 182, 2004/08

 Times Cited Count:2 Percentile:17.98(Materials Science, Multidisciplinary)

This paper presents an overview on ITER-supporting materials research and development activities and major achievements in Japan during the period from the Co-ordinated Technical Activities to date. In view of the completed engineering design of ITER during the Engineering Design Activities period, research and development efforts since then have been focused: those for reduction of component fabrication cost; those in support of domestic preparations of a structural technical code for construction; those necessary for operation, and been extended to component-level testing rather than pure material testing. They cover materials Research and Development for in-vessel components, vacuum vessel, cryogenic steels of superconducting mgnet and diagnostics components. Major achievements in each research and development area are highlighted and their impact or implication to the design, construction and operation of ITER is presented.

JAEA Reports

Characterization of cryogenically cooled silicon crystals, for the double-crystal monochromator on BL11XU at SPring-8

Tozawa, Kazukiyo*; Kiriyama, Koji*; Mitsui, Takaya; Shiwaku, Hideaki; Harami, Taikan

JAERI-Tech 2004-041, 27 Pages, 2004/03

JAERI-Tech-2004-041.pdf:5.11MB

Liquid-N$$_{2}$$-cooled Si crystals replaced water-cooled diamond crystals for the double-crystal monochromator on BL11XU at SPring-8. To use the whole energy from 6 keV to 70 keV, we developed the system of dual symmetric Si geometry, Si(111)/Si(311), which can be switched by a horizontal translation (X) stage perpendicular to the beam axis. The off-line experiment was performed to estimate the degree of the crystal strain, which may arise from the way of assembling in the crystal holder. With MoK$$alpha$$$$_{1}$$, rocking curves from the crystals were measured for the second crystal of the double-crystal diffractometer of parallel setting. Each of the observed full-width at half maximum (FWHM) was almost constant and identical to the calculated value wherever X-rays hit on the crystal surface. By the use of synchrotron radiation from the undulator the crystals were tested and then the characterization was performed. The observed intensities and rocking curves resulted in that each crystal was good for BL11XU and that the performance of X-ray reflection was improved.

Journal Articles

Cryogenically cooled monochromator with multi-crystal switching system on BL11XU at SPring-8

Shiwaku, Hideaki; Mitsui, Takaya; Tozawa, Kazukiyo*; Kiriyama, Koji*; Harami, Taikan; Mochizuki, Tetsuro*

AIP Conference Proceedings 705, p.659 - 662, 2004/00

We developed a multi-crystal switching system on a cryogenically cooled monochromator of JAERI materials science beamline, BL11XU. In order to study our science, it is necessary for ensuring at least the energy range of 6 - 70keV to employ Si(111) and Si(311) crystals. The principle of the crystal switching is that, two pair of crystals is arranged side by side, and they are translated in horizontal direction for exchanging. Indium sheets were inserted between both sides of crystals in order to improve thermal contact. Some adjustment stages of the monochromator were removed to avoid the crystal vibration and a sheet heater was installed on an X-axis stage to prevent over-cooling of X-axis stages. The monochromator is under commissioning at present. In comparison with a previous indirect water cooling diamond (111) crystal monochromator, this monochromator provides high flux intensity from 4 times to 7 times. It takes only 5 minutes to exchange and adjust crystals geometry. This mechanism will be easily applied to other crystals, for example asymmetrical-cut crystals.

Journal Articles

Characterization of cryogenically cooled dual symmetric silicon geometry, Si(111)/Si(311), for the double-crystal monochromator on BL11XU at SPring-8

Tozawa, Kazukiyo*; Kiriyama, Koji*; Mitsui, Takaya; Shiwaku, Hideaki; Harami, Taikan

AIP Conference Proceedings 705, p.671 - 674, 2004/00

Liquid-N$$_{2}$$-cooled Si crystals replaced water-cooled diamond crystals for the double-crystal monochromator on BL11XU at SPring-8. To use the whole energy from 6keV to 70keV, we adopted the system of alternative dual symmetric Si geometry, Si(111)/Si(311), which can be switched by a horizontal translation (X) stage perpendicular to the beam axis. Before the experiment on BL11XU, the off-line evaluation was performed to estimate the degree of the crystal strain, which may arise from the way of assembling. With MoK$$alpha$$$$_{1}$$, rocking curves from the crystals were measured for the second crystal of the double-crystal diffractometer of parallel setting. Each of the observed FWHM was almost constant and identical to the calculated value wherever X-rays hit on the crystal surface. By the use of synchrotron radiation from the undulator the crystals were tested and then the characterization was performed. The observed intensities and rocking curves resulted in that each crystal was good for BL11XU and that the performance of X-ray reflection was improved.

Journal Articles

Current status of the JAERI superconducting RF linac-based free-electron laser

Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki

Proceedings of 28th Linear Accelerator Meeting in Japan, p.31 - 32, 2003/08

Current status of the JAERI superconducting RF linac driven free-electron laser has been reported to describe some details of the FEL device and application researches. In the presentation, several progresses and achievements itimized below have been reproted briefly. Firstly a semi-perpetual, non-stop and continous operation of the JAERI cryogenic and refrigeration system is only available in the world for the JAERI superconducting linac-based FEL. Secondly a conceptual design and each vital component of the ERL(energy recovery linac) light souce has recently been developed and progressed quickly as the next-generation light source. Thirdly,large-scaled industrial applications have been briefly reported here.

JAEA Reports

Setup of the cryogenic cooling system on BL11XU at SPring-8

Kiriyama, Koji*; Shiwaku, Hideaki; Tozawa, Kazukiyo*

JAERI-Tech 2003-061, 21 Pages, 2003/07

JAERI-Tech-2003-061.pdf:3.25MB

Cryogenically cooled monochromator equipped with circulated-liquid-nitrogen cooling system has been developed on JAERI beam-line, BL11XU, at SPring-8. This cooling system has improved the performance of X-ray reflection. The system has difficulty for the operation because of a lack of the manual. So, it is required to establish a systematic guide of the system. Here we report a manual with fruitful know-how to operate the cryogenic cooling system on BL11XU safely and easily. The new manual is wholly tabulated and shows comments, instructions, and valve conditions in all one-step. The operator, by using this manual, can manipulate the system with no misoperation.

Journal Articles

Numerical estimation method of the hydrogen isotope inventory in the hydrogen isotope separation system for fusion reactor

Iwai, Yasunori; Yamanishi, Toshihiko; Nakamura, Hirofumi; Isobe, Kanetsugu; Nishi, Masataka; Willms, R. S.*

Journal of Nuclear Science and Technology, 39(6), p.661 - 669, 2002/06

 Times Cited Count:9 Percentile:53.47(Nuclear Science & Technology)

no abstracts in English

Journal Articles

New cryogenic steels and design approach for ITER superconducting magnet system

Nakajima, Hideo; Hamada, Kazuya; Okuno, Kiyoshi; Hada, Kazuhiko; Tada, Eisuke

Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 8 Pages, 2002/00

The Japan Atomic Energy Research Institute (JAERI) has conducted to develop a new design code for construction and operation/maintenance of the International Thermonuclear Experimental Reactor (ITER), which will be formed as a code case of ASME B&PV Code Section III, division 4, in collaboration with the ASME international. The new design code will also include the several new techniques and materials developed for each components of ITER. This paper describes the new cryogenic steels used in the magnet system and the design approach with taking account of unique features of the ITER superconducting magnets.

Journal Articles

A Comment on "A Pithall of a big project"

Tsuji, Hiroshi

Teion Kogaku, 36(11), P. 626, 2001/11

no abstracts in English

Journal Articles

Cryogenic system characteristics for the transitional heat disturbance of the CS model coil

Kawano, Katsumi; Hamada, Kazuya; Matsui, Kunihiro; Hara, Eiji*; Kato, Takashi; CS Model Coil Test Group

Teion Kogaku, 36(6), p.381 - 388, 2001/06

no abstracts in English

JAEA Reports

A Design stufy of hydrogen isotope separation system for ITER-FEAT

Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka

JAERI-Tech 2001-027, 29 Pages, 2001/03

JAERI-Tech-2001-027.pdf:1.11MB

no abstracts in English

JAEA Reports

Study on the flow reduction of forced flow superconducting magnet and its stable operation condition

Sugimoto, Makoto

JAERI-Research 2000-069, 134 Pages, 2001/03

JAERI-Research-2000-069.pdf:7.46MB

no abstracts in English

Journal Articles

Cold leak occurred at the large superconducting coil

Kato, Takashi; Kawano, Katsumi

Teion Kogaku Kyokai 2000-Nendo Reito Bukai Nenkan Koenshu, p.118 - 122, 2001/00

no abstracts in English

Journal Articles

Development of a 1-kg/s scale supercritical helium pump

Kawano, Katsumi; Kato, Takashi; Hamada, Kazuya; Shimba, Toru*; Tsuji, Hiroshi; *; *; *; *

Proceedings of 17th International Cryogenic Engineering Conference (ICEC17), p.255 - 258, 1998/00

no abstracts in English

55 (Records 1-20 displayed on this page)