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Kai, Tetsuya; Uchida, Toshitsugu; Kinoshita, Hidetaka; Seki, Masakazu; Oi, Motoki; Wakui, Takashi; Haga, Katsuhiro; Kasugai, Yoshimi; Takada, Hiroshi
Journal of Physics; Conference Series, 1021(1), p.012042_1 - 012042_4, 2018/06
Times Cited Count：0 Percentile：0.11(Nuclear Science & Technology)Dipu, A. L.; Ohashi, Hirofumi; Hamamoto, Shimpei; Sato, Hiroyuki; Nishihara, Tetsuo
Annals of Nuclear Energy, 88, p.126 - 134, 2016/02
Times Cited Count：5 Percentile：43.41(Nuclear Science & Technology)The tritium concentration in the high temperature engineering test reactor (HTTR) was measured during the high temperature continuous operation for 50 days. The tritium concentration in the primary helium gas increased after startup and reached a maximum value. It then decreased slightly over the course during the normal operation phase. Decrease of concentration of tritium in primary helium gas during the normal operation phase could be attributed to the effect of tritium chemisorption on graphite. The tritium concentration in the secondary helium gas showed a peak value during the power ramp up phase. Afterwards, it decreased gradually at the end of normal power operation. It was assessed that the concentration and total quantity of tritium in the secondary helium cooling system for the HTTR-Iodine Sulfur (IS) system can be maintained below the regulatory limits, which means the hydrogen production plant can be exempt from the safety function of the nuclear facility.
Takada, Hiroshi; Naoe, Takashi; Kai, Tetsuya; Kogawa, Hiroyuki; Haga, Katsuhiro
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.297 - 304, 2016/00
In J-PARC, we have continuously been making efforts to operate a mercury target of a pulsed spallation neutron source with rated power of 1-MW. One of technical progresses is to mitigate cavitation damages at the target vessel front induced by the 3-GeV proton beam injection at 25 Hz. We have improved the performance of a gas micro-bubbles injection into the mercury target, resulting that no significant cavitation damages was observed on the inner surface of target vessel after operation for 2050 MWh with the 300-kW proton beam. Another progress is to suppress the release of gaseous radioactive isotopes, especially tritium, during the target vessel replacement. We have introduced a procedure to evacuate the target system by an off-gas processing apparatus when it is opened during the replacement operation, achieving to suppress the tritium release through the stack. For example, the amount of released tritium was 12.5 GBq, only 5.4% of the estimated amount, after the 2050 MWh operation. After these progresses, the operating beam power for the pulsed spallation neutron source was ramped up to 500-kW in April, 2015.
Kawamoto, Yasuko*; Nakaya, Hiroyuki*; Matsuura, Hideaki*; Katayama, Kazunari*; Goto, Minoru; Nakagawa, Shigeaki
Fusion Science and Technology, 68(2), p.397 - 401, 2015/09
Times Cited Count：1 Percentile：9.74(Nuclear Science & Technology)To start up a fusion reactor, it is necessary to provide a sufficient amount of tritium from an external device. Herein, methods for supplying a fusion reactor with tritium are discussed. Use of a high temperature gas cooled reactor (HTGR) as a tritium production device has been proposed. So far, the analyses have been focused only on the operation in which fuel is periodically exchanged (batch) using the block type HTGR. In the pebble bed type HTGR, it is possible to design an operation that has no time loss for refueling. The pebble bed type HTGR (PBMR) and the block type HTGR (GTHTR300) are assumed as the calculation and comparison targets. Simulation is made using the continuous-energy Monte Carlo transport code MVPBURN. It is shown that the continuous operation using the pebble bed type HTGR has almost the same tritium productivity compared with the batch operation using the block type HGTR. The issues for pebble bed type HTGR as a tritium production device are discussed.
Kawamura, Yoshinori; Enoeda, Mikio; Yamanishi, Toshihiko; Nishi, Masataka
Fusion Engineering and Design, 81(1-7), p.809 - 814, 2006/02
Times Cited Count：14 Percentile：68.12(Nuclear Science & Technology)Tritium bred in the solid breeder blanket of a fusion reactor is extracted by passing of a helium sweep gas. Tritium is separated from sweep gas at the blanket tritium recovery system. Palladium membrane diffuser is one of the applicable processes for the blanket tritium recovery system. It is usually applied for hydrogen purification system such as TEP in ITER. However, it has been reported that the rate controlling step changes at lower hydrogen pressure such as the blanket sweep gas condition, and discussion about application for the blanket sweep gas condition is not enough. Recently, conceptual design of the demonstration reactor, named "DEMO2001", has been proposed from JAERI. In this report, the application of the Pd diffuser for the blanket sweep gas condition is discussed based on the condition of DEMO 2001.
Yokoyama, Sumi; Noguchi, Hiroshi; Kurosawa, Naohiro*
Hoken Butsuri, 40(4), p.376 - 384, 2005/12
A computer code named ACUTRI has been developed to assess tritium doses due to inhalation to the general public. ACUTRI can calculate the radiological impact of tritium gas (HT) and tritiated water (HTO) released accidentally to the atmosphere. The models in this code consist of a tritium transfer model including the oxidation of HT to HTO and the reemission of HTO from soil to the atmosphere and a dose calculation model. The atmospheric dispersion of the primary HT and HTO plumes and secondary HTO plume, which is reemitted from soil to the atmosphere, is calculated by using the Gaussian plume model. In this calculation, it is possible to analyze statistically on meteorology in the same way as a conventional dose assessment method according to the meteorological guideline of the Nuclear Safety Commission of Japan. Tritium concentrations in air and their resultant doses were calculated using the ACUTRI code under some conditions. In order to validate the model, calculations were compared with experimental results.
Kawamura, Yoshinori; Iwai, Yasunori; Nakamura, Hirofumi; Hayashi, Takumi; Yamanishi, Toshihiko; Nishi, Masataka
Fusion Science and Technology, 48(1), p.654 - 657, 2005/07
Times Cited Count：3 Percentile：24.22(Nuclear Science & Technology)Adding some amount of hydrogen to the helium sweep gas is effective for tritium extraction from blanket, but it causes permeation of tritium to a cooling system. In the design study of a demonstration reactor in JAERI, tritium leakage has been estimated to be about 20% of bred tritium under typical sweep gas conditions. If these tritiums are recovered under the ITER-WDS condition, tritium leakage limitation has to be less than 0.3% of typical case. Water vapor addition to the sweep gas is effective not only for blanket tritium extraction but also for permeation prevention. The reaction rate of isotope exchange is larger than the case of H
, and the equilibrium constant is also expected to be about 1.0. When the H/T ratio is 100, tritium inventory of breeder material is larger than the case of H addition. However it is not so large. In case of HO sweep, separation of tritiated water from helium seems to be easyer, but the process that changes HTO to HT is necessary.
Cristescu, I. R.*; Travis, J.*; Iwai, Yasunori; Kobayashi, Kazuhiro; Murdoch, D.*
Fusion Science and Technology, 48(1), p.464 - 467, 2005/07
Times Cited Count：3 Percentile：24.22(Nuclear Science & Technology)A model to simulate tritium behaviour after a release into a confined ventilated volume has been developed. The model assumes that for the investigated cases, tritium behaviour can be characterized by solving the dynamic equations of motion (the compressible Navier-Stokes equations) coupled with the classical k-
turbulence model to simulate the ventilation in the room and mass diffusion for tritium spreading. The GASFLOW-II fluid dynamics field code, developed through a Los Alamos National Laboratory (LANL) - Forschungszentrum Karlsruhe co-operation, was used as the computational tool to solve the equations that describe the processes. The numerical results have been validated with experimental data collected on the experimental facility (Caisson) at the Tritium Process Laboratory (TPL) Japan. Additionally an investigation of the influence of the obstacles to the tritium distribution inside the Caisson is presented.
Kikuchi, Taiji; Yamada, Hirokazu*; Saito, Takashi; Nakamichi, Masaru; Tsuchiya, Kunihiko; Kawamura, Hiroshi
JAERI-Tech 2004-026, 28 Pages, 2004/03
JAERI-Tech-2004-026.pdf:2.06MB
Iirradiation capsule for irradiation test of tritium breeder and inner capsule for pebble bed of tritium breeder is inserted. Post irradiation examination of tritium breeder will be performed after irradiation test. On cutting of irradiation capsule, sweep gas line should be sealed to prevent the tritium gas release or inflow of water to sweep gas line. However, general valve and plug cannot apply to sweep gas line sealing because of the effect of neutron irradiation or limited space in irradiation capsule. Therefore, sealing plug for sweep gas line sealing has to be developed. This report shows the development of sealing plug for sweep gas line sealing and operating procedure of sealing plug in irradiation capsule.
Oikawa, Akira; Miya, Naoyuki
Purazuma, Kaku Yugo Gakkai-Shi, 78(12), p.1308 - 1312, 2002/12
Tritium experience over decade in DD operation of JT-60 is summarized.Effluent of tritium in vacuum exhaust through the stack to environment always remains a level below detectable levels. Tritium concentration of drain is also below the limit of regurations of the local agreement amd the law. For a scheduled maintenance work of the in-vessel components, following an annual deuterium plasma discharge campaign, a 4-week no-deuterium plasma discharge campaign and the succeeded ventilation by room air allow to reduce tritium concentration on the surface of in-vessel components. A cooperative endeavour is underway for analysis of tritium behavior in JT-60.
Yokoyama, Sumi; Noguchi, Hiroshi; Ryufuku, Susumu*; Sasaki, Toshihisa*; Kurosawa, Naohiro*
JAERI-Data/Code 2002-022, 87 Pages, 2002/11
JAERI-Data-Code-2002-022.pdf:4.26MB
Tritium, which is used as a fuel of a D-T burning fusion reactor, is the most important radionuclide for the safety assessment of a nuclear fusion experimental reactor such as ITER. Thus, a computer code, ACUTRI, which calculates the radiological impact of tritium released accidentally to the atmosphere, has been developed, aiming to be of use in a discussion on licensing of a fusion experimental reactor and an environmental safety evaluation method in Japan. ACUTRI calculates an individual tritium dose based on transfer models specific to tritium in the environment. A Gaussian plume model is used for calculating the atmospheric dispersion of tritium gas (HT) and/or tritiated water (HTO). The environmental pathway model in ACUTRI considers the following internal exposures: inhalation from a primary plume (HT and/or HTO) released from the facilities and inhalation from a secondary plume (HTO) reemitted from the ground following deposition of HT and HTO. This report describes an outline of the ACUTRI code, a user guide and the results of test calculation.
Noguchi, Hiroshi; Yokoyama, Sumi; Fukatani, S.*; Kinouchi, Nobuyuki; Murata, Mikio; Amano, Hikaru; Atarashi-Andoh, Mariko
JAERI-Data/Code 99-022, 125 Pages, 1999/03
JAERI-Data-Code-99-022.pdf:6.76MB
no abstracts in English
Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka
Journal of Nuclear Science and Technology, 36(1), p.95 - 104, 1999/01
Times Cited Count：12 Percentile：66.16(Nuclear Science & Technology)no abstracts in English
Noguchi, Hiroshi
Purazuma, Kaku Yugo Gakkai-Shi, 74(7), p.712 - 715, 1998/07
no abstracts in English
Noguchi, Hiroshi; Yokoyama, Sumi
Nihon Genshiryoku Gakkai-Shi, 39(11), p.931 - 933, 1997/00
no abstracts in English
P.A.Davis*; W.J.G.Workman*; B.D.Amiro*; F.S.Spencer*; Noguchi, Hiroshi; Amano, Hikaru; Ichimasa, Yusuke*; Ichimasa, Michiko*
Fusion Technology, 28, p.840 - 845, 1995/10
no abstracts in English
Noguchi, Hiroshi
Fusion Technology, 27(2T), p.56 - 61, 1995/03
no abstracts in English
Murata, Mikio; Noguchi, Hiroshi
Nihon Genshiryoku Gakkai-Shi, 34(2), p.149 - 152, 1992/02
Times Cited Count：2 Percentile：43.73(Nuclear Science & Technology)no abstracts in English
Uchiyama, Gunzo; *; ; *; Sugikawa, Susumu; Maeda, Mitsuru; Tsujino, Takeshi
Radioact. Waste Manage. Nucl. Fuel Cycle, 17(1), p.63 - 79, 1992/00
no abstracts in English
Okuno, Kenji; *; Ohira, Shigeru; Naruse, Yuji
Journal of Nuclear Science and Technology, 28(6), p.509 - 516, 1991/06
no abstracts in English
