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Shibata, Toshio*; *; *; Tsuru, Toru*; Inoue, Hiroyuki*
JNC TJ8400 2001-008, 94 Pages, 2001/02
JNC-TJ8400-2001-008.pdf:2.05MB
A technical committee was organized in Japan Society of Corrosion Engineering to review and assess the study of overpacks in JNC. The corrosion models for candidate materials for overpaks were developed in terms of corrosion science to contribute the selection of material, establishment of experimental methods and life prediction of overpacks. It is expected that this report is used for the study of overpacks in the process of the research and development of high-level radioactive waste disposal.
Yamada, Susumu*
JNC TJ8400 2001-003, 87 Pages, 2001/02
JNC-TJ8400-2001-003.pdf:4.47MB
In view of necessity and importance of criticality surveillance systems for ensuring the safety of nuclear fuel manufacturing and reprocessing plants, 5-year basic studies and 4-year R&D studies on an on-line criticality surveillance system were carried out since 1991. This report is a summary of these series of studies. Noticing that the signal from a neutron detector is random in principle, these series of studies aimed to accumulate knowledge for developing an inexpensive criticality surveillance system with quick response based on the Auto-Regressive Moving Average (ARMA) model identification algorithm. During five-year basic studies on criticality surveillance system since 1991, we obtained knowledge required for developing a criticality surveillance system based on the ARMA model identification algorithm through (1)studies on recursive ARMA model identification algorithms most appropriate for estimating subcriticality form time series data under a steady state condition, (2)studies on pre-processing of signal from neutron detectors, (3) developing a new recursive ARMA model identification algolithm with small time delay to estimate time-dependent subcriticality, (4) proposing a basic concept for the elements required for an on-line criticality surveillance system, and (5) numerical analysis of data from the DCA experiments. During next four-year R&D studies on a criticality surveillance system since 1996, we (1) proposed modules required for a no-line criticality surveillance system, (2) revealed effectiveness of a adaptive digital filter (ADF) algorithm, as an important redundancy to the recursive ARMA model identification algorithm to be used in the signal processing module through numerical analysis of real data, (3) proposed a module of the Feynman-
method over 
ray signal and a fast signal processing module for ray signal, (4)devdoped a line-noise removal filter(Notch filter) and revealed its effectiveness for the DCA ...
Yamada, Susumu*
JNC TJ8400 2000-051, 122 Pages, 2000/02
JNC-TJ8400-2000-051.pdf:2.15MB
Developing an inexpensive on-line criticality surveillance system is required for ensuring the safety of nuclear fuel reprocessing plants. Based on the series of researches for five years, R&D study on On-line Criticality Surveillance System has been carricd out since 1996. The concept of this Criticality Surveillance System is based on the Auto-Regressive Moving Average (ARMA) model identification algorithms to the time series of signal fluctuation of a neutron detector. We have proposed several new ideas of modification to the original design of the Criticality Surveillance System, and also reported some results of numerical analysis over the DCA experiments. In those days, DOS/V personal computers with Microsoft Windows have came into wide use instead of those based on the MS-DOS, which have been popular in Japan. NEC, a major maker of MS-DOS computers, stopped the production of MS-DOS computers and changed their management policy toward production of DOS/V personal computers. Our researches have been developed using MS-DOS computers. For the effective use of these important results, it became an urgent theme to transplant all programs developed on MS_DOS computers into computers with the OS, which is not easily affected by commercialism. Since the design concept should be based on high reliability, electromagnetic disturbance-free and high expandability, and also computers have achieved remarkably high performance as well as low price in these days, these computers should be used not only as a simple signal processing unit but also a totally integrated signal analyzing system along with conventional signal analyzing software in stead of IC chips with analyzing soft wares. This configuration enables us to easily introduce newly developed techniques and to provide supplement information. Then, this approach can enhance the reliability of the Criticality Surveillance System without addition of any special devices, and also provide the flexibility of ...