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Fukuda, Kodai
Proceedings of 4th Reactor Physics Asia Conference (RPHA2023) (Internet), 4 Pages, 2023/10
Brief evaluations were performed using the N-F model to quantitatively clarify the effect of thermal expansion on the consequences of criticality accidents in the water-moderated fuel-particle-dispersion system. The analysis clarified that ignoring thermal expansion can lead to underestimation or overestimation of the consequences by several tens of percent. It is concluded that evaluators can ignore the thermal expansion when they evaluate the consequences of the prompt supercritical transient in water-moderated solid fuel-dispersion systems, such as fuel debris systems. Only the Doppler effect can be considered when the fuel-temperature-feedback coefficient is prepared. However, depending on the required accuracy, the evaluators should take care of the error caused by ignoring thermal expansion.
Araki, Shohei; Gunji, Satoshi; Arakaki, Yu; Murakami, Takahiko; Yoshikawa, Tomoki; Hasegawa, Kenta; Tada, Yuta; Izawa, Kazuhiko; Suyama, Kenya
Proceedings of 4th Reactor Physics Asia Conference (RPHA2023) (Internet), 4 Pages, 2023/10
To conduct integrated thermal power measurements for the performance test of the modified STACY, we re-analyzed the experimental data measured in the solution fuel STACY using the activation method. We validated its feasibility under the limited number of activation detectors. The re-analyzed results of the activation method by using MVP and PHITS with JENDL-4.0 indicated that the effect of the difference of the position between activation detectors was small enough, and the results agreed with that of the fission product analysis within almost 10%. It is conceivable that the activation method could be adopted instead of the fission product analysis.
Kimura, Atsushi; Endo, Shunsuke; Rovira Leveroni, G.; Nakamura, Shoji
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