著者

山口 拓真 師岡 愼一

出版者

日本混相流学会

雑誌

混相流 (ISSN:09142843)

巻号頁・発行日

pp.2018.004, (Released:2018-05-18)

参考文献数

15

被引用文献数

2

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The severe accident in Fukushima daiichi nuclear power plant revealed the importance of molten core cooling system without the electric power, then cooling system by natural circulation flow has attracted attention. The heat removal performance of this system depends on the natural circulation flow rate, so it is essential to predict the flow rate accurately for the safety design. The purpose of this study is to develop the evaluation method for the natural circulation, and to examine its accuracy dependence on the channel shape. Experiments were carried out at atmospheric pressure, using room temperature air-water flow. We used seven kinds of channels with various shape and diameter, and measured natural circulation flow rate and pressure drop for each channel. Predictive analysis was conducted by our method based on balance between driving force and pressure drop in the loop channel. The major results are as follows: (1) It is possible to predict the natural circulation flow rate with an error of less than 20 percent for various shaped channels. The average and standard deviation for the ratio between calculated and experimental flow rate is 0.98 and 0.047. (2) Two phase prediction method for pressure drop has maximum 15 % error. To improve the prediction accuracy, it is important to improve the prediction of the void fraction and the two-phase multiplier.

著者

多田 宏次郎 師岡 愼一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00577-16-00577, 2017 (Released:2017-06-25)

参考文献数

18

被引用文献数

1

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This paper presents the pressure drop prediction of BWR fuel assembly without experiment. To evaluate the core performance, pressure drop of fuel assembly is one of the key design parameters. The shape of fuel assembly is complicated and the spacer has a strong effect on pressure drop. Therefore, to obtain the pressure drop of fuel assembly, the experiments are needed. However, the experiments need a lot of time and money. In the authors' previous study, the friction coefficient and spacer loss coefficient under single phase flow condition were evaluated using CFD analysis and total pressure drop under two phase flow condition were predicted using these coefficients and verified by the data of the tight lattice bundle. The purpose of this study is to predict the pressure drop of BWR fuel assembly without experiments. The predicted pressure drop by the previous study's method was compared with the pressure drop data for full-scale high-burnup 8x8 fuel assembly covering the operating BWR conditions. The following conclusions are obtained; (1)The average and standard deviations of prediction accuracy (calculation/experiment) were 1.046 and 0.023, (2)The prediction accuracy of this method is almost same as that of the current BWR design method.