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Hazama, Taira; Mori, Tomoaki; ; Aihara, Nagafumi; ; Yoshida, Mamoru; *
JNC TN9400 2001-044, 136 Pages, 2001/05
JNC-TN9400-2001-044.pdf:3.97MB
A Subcriticality measurement technique was developed to improve safety and efficiency of criticality safety control in nuclear fuel processing facilities. In the development, two measurement techniques based on reactor noise analysis were selected as candidates of subcriticality measurement technique applicable to severe situations in FBR fuel reprocessing plants. The research activity was performed in Deuterium Critical Assembly (DCA) which was partly reconstructed from the original core of the advanced thermal reactor, so that light water and FBR type fuel could be used as in the FBR fuel reprocessing plants. Through the research, each technique was improved to satisfy criteria for subcriticality monitoring technique in FBR fuel reprocessing plant. Since the two techniques have basically different features while using common devices,thier combination would be a simple and reliable measurement system. This report summarizes processes and results of the research activity in DCA.
Yoshida, Mamoru; ; *; Aihara, Nagafumi
PNC TN9410 96-249, 60 Pages, 1996/09
A new fuel-rods storage rack has been manufactured to store DCA and JOYO type fuel-rods in a fuel-rods storage house attached to the Criticality Engineering Section Facility. For the manufacture of fuel-rods storage rack, a safety design evaluation was performed about criticality safety, earthquake-proof and dose equivalent rate. The calculation of design evaluation was performed by using SCALE-4, SAP-IV and ANISN code system, respectively. We could understand the following informations from the safety design evaluation: (1)As a result of criticality evaluation, a maximum Keff value was 0.568 by the use of JOYO type fuel-rods with all number of 300 fuel-rods. This means that the sub-criticality is kept in any situation. (2)As a result of earthquake-proof evaluation, it was confirmed that the new storage rack showed less value than the permitted stress from an analytical result when the yield point against the earthquake power of standard earthquake oscillation or the static earthquake power was set as a permitted limit. (3)As a result of evaluation for the dose equivalent rate, a maximum dose equivalent rate was a case by the use of DCA 3.4% enriched MOX fuel-rods with all number of 300 fuel-rods.
Aihara, Nagafumi; *
PNC TN9410 95-344, 61 Pages, 1995/12
Input constants of fuels or structural materials which compose the core were summarized to perform a nuclear calculation. These fuels or structural materials were produced to perform experiments of reactor physics by using deuterium critical Assembly(DCA). Although a part of DCA input constants were shown in the previous DCA handbook (I) published as the first edition(SN941 74-22), a report of this time was summarized on new fuels or structural materials produced after those such as multi-fuel rods cluster, high enriched fuels, fuels with Gd
O
and so on. Input constants are consisted of composition, density and dimension on each material and are made of score-sheets or mill- sheets based on the fabrication materials. These input constants are utilized for the analysis of criticality safety experiment to measure sub-criticality that is our program in near future.