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Metsugi. Shoichi
Journal of the Physical Society of Japan, 74(6), p.1865 - 1870, 2005/06
Times Cited Count：0 Percentile：0.00(Physics, Multidisciplinary)We study the problem of convergence of sampling in protein simulation originating in the multidimensionality of protein's conformational space. Since several important physical quantities are given by second moments of dynamical variables, we attempt to obtain the time of simulation necessary for their sufficient convergence. We perform a molecular dynamics simulation of a protein and the subsequent principal component (PC) analysis as a function of simulation time T. As T increases, PC vectors with smaller amplitude of variations are identified and their amplitudes are equilibrated before identifying and equilibrating vectors with larger amplitude of variations. This sequential identification and equilibration mechanism makes protein simulation a useful method although it has an intrinsic multidimensional nature.
Homma, Toshimitsu; Tomita, Kenichi*; Hato, Shinji*
Nuclear Engineering and Technology, 37(3), p.245 - 258, 2005/06
This paper addresses two types of uncertainty: stochastic uncertainty and subjective uncertainty in probabilistic accident consequence assessments. The off-site consequence assessment code OSCAAR has been applied to uncertainty and sensitivity analyses on the individual risks of early fatality and latent cancer fatality in the population due to a severe accident. A new stratified meteorological sampling scheme was successfully implemented into the trajectory model for atmospheric dispersion and the statistical variability of the probability distributions of the consequence was examined. A total of 65 uncertain input parameters was considered and 128 runs of OSCAAR were performed in the parameter uncertainty analysis. The study provided the range of uncertainty for the expected values of individual risks of early and latent cancer fatality close to the site. In the sensitivity analyses, the correlation/regression measures were useful for identifying those input parameters whose uncertainty makes an important contribution to the overall uncertainty for the consequence.
Nagaya, Yasunobu; Mori, Takamasa
Journal of Nuclear Science and Technology, 42(5), p.428 - 441, 2005/05
Times Cited Count：73 Percentile：96.63(Nuclear Science & Technology)A new method to estimate a change in the effective multiplication factor due to the perturbed fission source distribution has been proposed for Monte Carlo perturbation calculations with the correlated sampling and differential operator sampling techniques. The method has been implemented into the MVP code for verification. Simple benchmark problems have been set up for fast and thermal systems and the applicability of the method has been verified with the problems. In consequence, it has been confirmed that the method is very effective to estimate the change. It has been also shown that there are some cases where the perturbed source effect is significant and the change in reactivity cannot be estimated accurately without taking the effect into account. Even in such cases, the new method can estimate the perturbed source effect and the estimation of the change in reactivity has been remarkably improved.
Sakaba, Nariaki; Furusawa, Takayuki; Kawamoto, Taiki; Ishii, Yoshiki; Ota, Yukimaru
Nuclear Engineering and Design, 233(1-3), p.147 - 154, 2004/10
Times Cited Count：14 Percentile：64.25(Nuclear Science & Technology)The HTTR mainly consists of the core components, reactor pressure vessel, cooling systems, instrumentation and control systems, and containment structures. The design of remaining utility systems is described in this paper. They are: auxiliary helium systems which include the helium purification system, the helium sampling system, and the helium storage and supply system; fuel handling and storage system. The helium purification systems are installed in the primary and secondary helium cooling systems in order to reduce the quantity of chemical impurities. The helium sampling systems monitor the concentration of impurities. The helium storage and supply systems keep the steady pressure of the helium system during the normal operation. The fuel handling and storage system is utilised to handle the new and spent fuels safely and reliably.
Lee, C. G.; Iguchi, Kazunari; Esaka, Konomi; Magara, Masaaki; Esaka, Fumitaka; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Analytica Chimica Acta, 517(1-2), p.215 - 220, 2004/07
Times Cited Count：4 Percentile：13.30(Chemistry, Analytical)In this study, we discussed the feasibility of solid sample ETV-ICP-MS for the particle analysis of the environmental swipe samples in order to establish the fission track-ETV-ICP-MS method. Samples used were solid samples containing Tl, Pb and U in polycarbonate film, and their standard solutions. The analytical performance will be reported in terms of the optimization of temperature program, and sensitivity and precision in isotope ratio measurement.
Liu, X.*; Tomita, Kenichi*; Homma, Toshimitsu
JAERI-Research 2002-004, 37 Pages, 2002/03
JAERI-Research-2002-004.pdf:2.14MB
One important step in Level 3 Probabilistic Safety Assessment is meteorological sequence sampling, on which the previous studies were mainly related to code systems using straight line plume model and more efforts are needed for trajectory puff model such as the OSCAAR code system. This report describes the development of a new meteorological sampling scheme for the OSCAAR code system that explicitly considers population distribution. A group of principles was set forth for the development of this new sampling scheme, including completeness, stratification, sample allocation, practicability and so on. The calculation results illustrate that although it is quite difficult to idealize stratification of meteorological sequences based on a few environmental parameters the new scheme do gather the most inverse conditions in a single subset of meteorological sequences. The size of this subset may be as small as a few dozens, so that the tail of a CCDF curve is possible to remain relatively static in different trials of the PCA code system.
Liu, X.; Homma, Toshimitsu
JAERI-Tech 2001-054, 49 Pages, 2001/08
JAERI-Tech-2001-054.pdf:1.54MB
no abstracts in English
Li, Y.*; Kato, Daisuke*; Shibata, Katsuyuki; Onizawa, Kunio
International Journal of Pressure Vessels and Piping, 78(4), p.271 - 282, 2001/04
Times Cited Count：5 Percentile：40.50(Engineering, Multidisciplinary)no abstracts in English
Sawa, Kazuhiro; Tobita, Tsutomu*; Ueta, Shohei; Suzuki, Shuichi*; Sumita, Junya; Sekita, Kenji; Aoki, Kazunori*; Ouchi, Hiroshi
JAERI-Research 2001-002, 33 Pages, 2001/02
JAERI-Research-2001-002.pdf:1.42MB
no abstracts in English
Nishimura, Hideo; Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Takahashi, Tsukasa; Gunji, Katsubumi; Miyamoto, Yutaka; Yasuda, Kenichiro; Tsuruta, Yasuhiro; Tsuda, Shinji; et al.
Heisei 11-Nendo Hosho Sochi Semina Koenroku Tekisuto, p.95 - 107, 2000/01
no abstracts in English
Homma, Toshimitsu; Liu, X.; Tomita, Kenichi*
Proceedings of 5th International Conference on Probabilistic Safety Assessment and Management (PSAM-5), p.2753 - 2758, 2000/00
no abstracts in English
Nagaya, Yasunobu; Mori, Takamasa
Proceedings of the ANS International Topical Meeting on Advances in Reactor Physics and Mathematics and Computation into the Next Millennium (PHYSOR2000) (CD-ROM), p.13 - 0, 2000/00
no abstracts in English
Sakaba, Nariaki; Emori, Koichi; Saruta, Toru
JAERI-Tech 99-072, p.125 - 0, 1999/10
no abstracts in English
Nishimura, Hideo
Kaku Busshitsu Kanri Senta Nyusu, 28(8), p.5 - 7, 1999/08
no abstracts in English
Takada, Hiroshi; Yoshizawa, Nobuaki*; Kosako, Kazuaki*;
JAERI-Data/Code 98-005, 101 Pages, 1998/02
JAERI-Data-Code-98-005.pdf:3.57MB
no abstracts in English
Nishimura, Hideo; Magara, Masaaki; Oda, Tetsuzo; Usuda, Shigekazu; Watanabe, Kazuo; Adachi, Takeo; Noguchi, Hiroshi
Dai-18-Kai Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Nenji Taikai Hobunshu, p.71 - 78, 1997/11
no abstracts in English
Matsui, Hiroshi
Earozoru Kenkyu, 11(4), p.337 - 348, 1996/00
no abstracts in English
; Tsuji, Yoshiyuki*; ; Nakamura, Hideo; ; Kukita, Yutaka
Nihon Kikai Gakkai Tokai Shibu Dai-45-Ki Sokai Koenkai Koen Rombunshu No.963-1, 0, p.177 - 178, 1996/00
no abstracts in English
Murata, Isao; Shindo, Ryuichi; Shiozawa, Shusaku
Proc. of the 8th Int. Conf. on Radiation Shielding, p.365 - 370, 1994/00
no abstracts in English
Homma, Toshimitsu;
JAERI-M 93-207, 36 Pages, 1993/10
no abstracts in English
