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Journal Articles

Spatial pattern formation in asynchronous cellular automata with mass conservation

Suzudo, Tomoaki

Physica A, 343, p.185 - 200, 2004/11

https://doi.org/10.1016/S0378-4371(04)00857-X

Times Cited Count：22 Percentile：70.5(Physics, Multidisciplinary)

This paper proposes a class of 2-dimensional asynchronous cellular automata with conservation of mass, for the formation of patterns in groups, and describes the merits given by this methodology. A cellular automaton rule causing a specified kind of pattern was designed manually. Thanks to this realistic modeling method reflecting nature, the mechanism of pattern formation was found to be similar to real chemical processes. A search technique using genetic algorithm is applied to find pattern-forming CAs, and it successfully find a few types of spontaneous pattern formations. This technique is expected to be applied to a wide range of potential studies related to self-organization.

JAEA Reports

Investigation of automatic shutdown of HTTR on May 21st, 2003

Hirato, Yoji; Saito, Kenji; Kondo, Makoto; Sawahata, Hiroaki; Motegi, Toshihiro; Tsuchiyama, Masaru*; Ando, Toshio*; Mizushima, Toshihiko; Nakazawa, Toshio

JAERI-Tech 2004-037, 33 Pages, 2004/04

JAERI-Tech-2004-037.pdf:4.08MB

HTTR (High Temperature Engineering Test Reactor) was operated from May 6th, 2003 to June 18th, 2003 to obtain operation data in parallel loaded operation mode and in safety demonstration tests. Operated with the reactor power at 60% of the rated power on May 21st, HTTR was automatically scrammed by a signalof "Primary coolant flow rate of the Primary Pressurized Water Cooler (PPWC): Low". The cause of the shutdown was the primary gas circulator (A) automatically stopped. The primary coolant flow rate of the PPWC decresed and reached the scram set value due to the gas circulator stop. As a result of investigation, it became clear that the cause of the gas circulator stop was malfunction of an auxiliary relay which monitored electric power of a circuit breaker in power line of the gas circulator. The cause of malfunction was deterioration of the relay under high temperature condition because the relay was installed beside an electric part which was heated up by electricity.

JAEA Reports

Behavior of the regulating control rod on automatic power control mode in operation of JMTR

Nagao, Yoshiharu; Miyazawa, Masataka; Komukai, Bunsaku; Fujiki, Kazuo

JAERI-Tech 2003-067, 33 Pages, 2003/07

JAERI-Tech-2003-067.pdf:1.63MB

no abstracts in English

JAEA Reports

Findings of the reactor automatic shutdown caused by a signal of a primary coolant flow rate of the PPWC:Low in the HTTR

Takamatsu, Kuniyoshi; Nakazawa, Toshio; Furusawa, Takayuki; Homma, Fumitaka; Saito, Kenji; Kokusen, Shigeru; Kamata, Takashi; Ota, Yukimaru; Ishii, Yoshiki; Emori, Koichi

JAERI-Tech 2003-062, 94 Pages, 2003/06

JAERI-Tech-2003-062.pdf:26.47MB

no abstracts in English

Journal Articles

Automatic measurement of low level contamination on concrete surfaces

Tachibana, Mitsuo; Ito, Hirokuni; Shimada, Taro; Yanagihara, Satoshi

Proceeding of International Waste Management Symposium 2002 (WM '02) (CD-ROM), 8 Pages, 2002/00

Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm $^{2}$ for $^{60}$ Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m $^{2}$ /h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application.