Horonobe Underground Research Laboratory project overview of the pilot borehole investigation of the ventilation shaft (PB-V01); Hydrogeological investigation

Yabuuchi, Satoshi; Kunimaru, Takanori; Ishii, Eiichi; Hatsuyama, Yoshihiro*; Ijiri, Yuji*; Matsuoka, Kiyoyuki*; Ibara, Tetsuo*; Matsunami, Shinjiro*; Makino, Akiya*

JAEA-Data/Code 2008-026, 62 Pages, 2009/02

JAEA-Data-Code-2008-026.pdf:8.23MB

The Pilot Borehole Investigation of the Ventilation Shaft was conducted in Horonobe, Hokkaido, Japan from October 2007 to March 2008. Main purpose of the investigation is to understand geological, hydrogeological and hydrochemical properties of the formation where the Ventilation Shaft has been excavated. Hydraulic packer tests show that hydraulic conductivity lies in the range from 1.1E-11 to 1.4E-7 m/sec down to 500 m in depth. This heterogeneity mainly depends on the distribution and permeability of groundwater inflow points, which were detected by Fluid Electric Conductivity logging. High conductive zones were found between 263 m and 290 m, 355 m and 370 m of the depth in the pilot borehole. An effective method for reducing groundwater inflow should be considered for the deeper Ventilation Shaft excavation.

Extended steady-state and high-beta regimes of net-current free heliotron plasmas in the Large Helical Device

Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.

Nuclear Fusion, 47(10), p.S668 - S676, 2007/10

https://doi.org/10.1088/0029-5515/47/10/S15

The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 510 m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.

Absence of recombination of neighboring H atoms in highly purified solid parahydrogen; Electron spin resonance, electron-nuclear double resonance, and electron spin echo studies

Kumada, Takayuki; Sakakibara, Masahiro*; Nagasaka, Toshimitsu*; Fukuta, Hiroya*; Kumagai, Jun*; Miyazaki, Tetsuo*

Journal of Chemical Physics, 116(3), p.1109 - 1119, 2002/01

https://doi.org/10.1063/1.1426410

We have studied diffusion and recombination of H atoms in solid hydrogen using ESR, ENDOR, and ESE spectrometer. The rate constant for recombination of H atoms in highly purified parahydrogen was found to be much smaller than that expected by diffusion coefficient. This result indicates that the H atoms do not recombine in the absence of energy dispersion path in highly purified parahydrogen.