Double diffusive dissolution model of UO pellet in molten Zr cladding

Ito, Ayumi*; Yamashita, Susumu; Tasaki, Yudai; Kakiuchi, Kazuo; Kobayashi, Yoshinao*

Journal of Nuclear Science and Technology, 60(4), p.450 - 459, 2023/04

https://doi.org/10.1080/00223131.2022.2114956

Clarification of debris formation conditions on the basis of the sampling data and experimental study using simulated fuel debris, 6; Evaluation of damage by reaction between metallic debris and structural materials in lower plenum

Nagae, Yuji; Sato, Takumi; Ito, Ayumi*; Ueda, Shigeru*

no journal, , 

We summarized the results of small-scale tests conducted at Tokyo Tech, Tohoku Univ. and JAEA, and will report the results of evaluating damage behavior of lower plenum by metal debris during severe accident. Molten Zr concentration contributed to the reactivity with the structure and to the reaction with oxide debris during the formation of the molten metal pool. Although Zr concentration tends to decrease due to various reactions, there is a possibility that metal debris with low oxygen concentration might form a molten pool at the pedestal. If the metal debris would have a high zirconium concentration, it might cause a eutectic reaction with the structural materials. In contrast, if Zr concentration would be low, the reaction with the structural material could be limited, and thermal damage and creep damage due to temperature rise are considered to be dominant.