Low-reflection RF window for ACS cavity in J-PARC linac

Tamura, Jun; Kondo, Yasuhiro; Morishita, Takatoshi; Ao, Hiroyuki*; Naito, Fujio*; Otani, Masashi*; Nemoto, Yasuo*

Journal of Physics; Conference Series, 1067(5), p.052009_1 - 052009_6, 2018/09

https://doi.org/10.1088/1742-6596/1067/5/052009

In the Japan Proton Accelerator Research Complex (J-PARC) linac, the Annular-ring Coupled Structure (ACS) cavities have been stably operating. To maintain this operation availability, we manufactured three pillbox-type RF windows for the ACS cavities in fiscal year 2015 and 2017. It is desirable to minimize the RF reflection of the RF window to prevent standing waves from exciting between the cavity and the RF window, and not to significantly change the optimized coupling factor between the cavity and the waveguide. To realize the minimization, the relative permittivities of the ceramic disks of the RF windows were evaluated by measuring the resonant frequencies of the pillbox cavity containing the ceramic disk. On the basis of the evaluated relative permittivities, the pillbox-part lengths of the RF windows were determined. The measured Voltage Standing Wave Ratios (VSWRs) of the manufactured RF windows are just about 1.08 and these are applicable for the practical use.

Crack formation in cementitious materials used for an engineering barrier system and their impact on hydraulic conductivity from the viewpoint of performance assessment of a TRU Waste disposal system

Hirano, Fumio; Otani, Yoshiteru*; Kyokawa, Hiroyuki*; Mihara, Morihiro; Shimizu, Hiroyuki*; Honda, Akira

Nihon Genshiryoku Gakkai Wabun Rombunshi, 15(2), p.97 - 114, 2016/06

https://doi.org/10.3327/taesj.J15.015

A mechanical analysis code MACBECE2014 has been developed at the Japan Atomic Energy Agency to make realistic simulations of the physical integrity of the near-field for performance assessment of geological disposal of TRU waste in Japan. The MACBECE2014 code can be used to evaluate long-term changes in the mechanical behavior and any subsequent changes in the permeability of engineering barrier components, including crack formation in cementitious materials caused by expansion due to metal corrosion. Simulated results of the TRU waste disposal system with a bentonite buffer using the MACBECE2014 code demonstrated that the low permeability of the engineering barrier system could be maintained for long time periods after disposal because the physical integrity of the bentonite buffer remained intact. Simulated results of the disposal system with a concrete backfill, showed that crack formation leads to a significant increase in permeability of the system.

Analytical surveillance on production methods of homogeneous and uniform solid materials from spent ion exchange residuum after ion coupled plasma volume-reduction process

Otani, Hiroshi; Mizui, Hiroyuki; Higashiura, Norikazu; Bando, Fumio*; Endo, Nobuyuki*; Yamagishi, Ryuichiro*; Kume, Kyo*

Heisei-25-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 16, P. 66, 2014/10

no abstracts in English

Current status of a time-of-flight single crystal neutron diffractometer SENJU at J-PARC

Tamura, Itaru; Oikawa, Kenichi; Kawasaki, Takuro; Ohara, Takashi; Kaneko, Koji; Kiyanagi, Ryoji; Kimura, Hiroyuki*; Takahashi, Miwako; Kiyotani, Tamiko*; Arai, Masatoshi; et al.

Journal of Physics; Conference Series, 340, p.012040_1 - 012040_4, 2012/02

https://doi.org/10.1088/1742-6596/340/1/012040

Impact of partitioning and transmutation on high-level waste disposal for the fast breeder reactor fuel cycle

Nishihara, Kenji; Oigawa, Hiroyuki; Nakayama, Shinichi; Ono, Kiyoshi; Shiotani, Hiroki

Journal of Nuclear Science and Technology, 47(12), p.1101 - 1117, 2010/12

https://doi.org/10.3327/jnst.47.1101

The impact of partitioning and/or transmutation (PT) technology on the high level waste management was investigated for the fast breeder reactor (FBR) fuel cycle. Three different fuel cycle scenarios involving PT technology were analyzed: (1) partitioning process only (separation of some fission products), (2) transmutation process only (separation and transmutation of minor actinides), and (3) both partitioning and transmutation. It was found that the introduction of FBR cycle without PT yields a smaller repository after 65 years of predisposal storage than the LWR after 50 years by a factor of up to 0.65. The impact of the partitioning-only process on the repository is not significant, but that of the transmutation-only process produces a reduction of area by a factor of 0.25 after 80 years of storage, and that of a coupled partitioning and transmutation by two orders of magnitude after 60 and 295 years of storage for the glass waste and the calcined waste with Sr-Cs, respectively.

Complementary spectroscopy of tin ions using ion and electron beams

Ohashi, Hayato*; Suda, Shintaro*; Tanuma, Hajime*; Fujioka, Shinsuke*; Nishimura, Hiroaki*; Nishihara, Katsunobu*; Kai, Takeshi; Sasaki, Akira; Sakaue, Hiroyuki*; Nakamura, Nobuyuki*; et al.

Journal of Physics; Conference Series, 163, p.012071_1 - 012071_4, 2009/06

https://doi.org/10.1088/1742-6596/163/1/012071

Extreme ultra-violet (EUV) emission spectra of multiply charged tin ions were measured in the wavelength range of 10-22 nm following charge exchange collisions or the electron impact excitation of tin ions. In charge exchange collisions, we observed both the resonance lines and the emission lines corresponding to the transitions between the excited states. On the other hand, we observed mainly the resonance lines in the electron impact experiments. We can distinguish the resonance lines from other emission lines in the charge exchange spectrum by comparison with the emission lines in the electron impact spectrum.

R&D status of superconducting proton linear accelerator for ADS at JAERI

Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 6 Pages, 2003/04

no abstracts in English

Cold test of 600MHz superconducting cryomodule for high intensity proton linac

Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu*; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.

Proceedings of 21st International Linear Accelerator Conference, p.488 - 490, 2003/00

Development of a superconducting proton linac is in progress in collaboration with KEK. In order to demonstrate cavity performance and to study stable accelerating field in a pulsed operation, a 600MHz superconducting cryomodule has been fabricated. The cryomodule includes two 5-cell superconducting cavities of =0.6 and is designed to perform 2K operation. Cold tests of the cryomodule have been performed at the temperature of 4K and 2K. In the tests, heat leak to the cavities, loaded quality factors, tuning sensitivities, frequency shifts against helium vessel pressure and Lorentz force detuning of the cavities were measured. Most of the measured data agreed with their design values, except for the heat leak and the Lorentz force detuning. As the preliminary horizontal test of the cryomodule, high power RF test has been also performed, where the surface peak fields of 10 and 16 MV/m were achieved in CW and pulsed operation, respectively. Now, the optimization of the RF control system is in progress to demonstrate stable accelerating field in a pulsed operation.

Axial Dependence of Partial Void Reactivity in a Light Water-Cooled, Heavy Water-Moderated, Pressure-Tube Reactor

Aihara, Nagafumi; Fukumura, Nobuo; Kadotani, Hiroyuki*; Hachiya, Yuki

Nuclear Science and Engineering, 109, p.158 - 170, 1991/00

https://doi.org/10.13182/NSE91-A28515

None

Storage and disposal of the high level waste from the advanced FBR fuel cycle

Nishihara, Kenji; Oigawa, Hiroyuki; Nakayama, Shinichi; Fujiwara, Takeshi; Kobayashi, Hidekazu; Kano, Shigeru; Sasage, Kenichi; Yamashita, Teruo; Ono, Kiyoshi; Shiotani, Hiroki

no journal, , 

The reduction of the storage facility and repository were evaluated for the cases with or without partitioning of Sr-Cs and transmutation of MA in the advanced FBR fuel cycle with the cost estimation for the storage facilities, transporting and repository. As the result, the transmutation of minor actinides is inevitable for the small repository because the heat generation by Am is considerable in FBR. The introduction of partitioning, transmutation and long-term storage enable the very compact layout in the repository like TRU wastes such as hulls and end-pieces of the fuel assembly. The cost for the storage and disposal in this case is much smaller than that in other cases, which mitigates the cost increase by the separation process and transmutor.