Recent status of the cryogenic sample environment at the MLF, J-PARC

Ishikado, Motoyuki*; Takahashi, Ryuta*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ishimaru, Sora*; Yamauchi, Sara*; Kawamura, Seiko; Kira, Hiroshi*; Sakaguchi, Yoshifumi*; Watanabe, Masao; et al.

JPS Conference Proceedings (Internet), 41, p.011010_1 - 011010_7, 2024/05

https://doi.org/10.7566/JPSCP.41.011010

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. 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.

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

https://doi.org/10.1088/1742-6596/1021/1/012085

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

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2016_01/jspf2016_01-21.pdf

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.

Development of a neutron-imaging detector based on pulse-height correlation between two superconducting tunnel junctions on a LiBO crystal

Nakamura, Tatsuya; Katagiri, Masaki; Chen, Y. E.*; Ukibe, Masahiro*; Okubo, Masataka*

Nuclear Instruments and Methods in Physics Research A, 559(2), p.766 - 768, 2006/04

https://doi.org/10.1016/j.nima.2005.12.131

We have been developing a position-sensitive neutron detector, which exhibits a high spatial resolution of the order of 10 microns and high detection efficiency. The analysis on the pulse-heights or on the time-delay between the STJs gives incident positions of the neutrons. In this paper, the response of the STJs/LBO neutron detector measured using a cold neutron beam is presented. The two STJs have the same size of 50 50 m and their distance is 1.3 mm. The count intensity in the correlation map varied depending on the incident position of the neutron beam which gives an evidence for the position-sensitivity of the detector. These experimental results were qualitatively understood by a simple solid-angle model.

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-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, 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.

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

https://doi.org/10.1063/1.1757885

Liquid-N-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, 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.

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.

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.

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

https://doi.org/10.2221/jcsj.36.381

no abstracts in English