Evaluation of the in-vessel heat transfer for the debris removal of the Fukushima Daiichi nuclear power plant

Abstract As the investigation on the decommissioning of Fukushima Daichi Power Plant (F1) advances further, deepening the knowledge on the reactor building behavior under the different debris removal method is a vital assessment to be made. As the submersion-method has been well investigated in the past, the main scope of the current paper will be on the dry-method where it is assumed that the debris cooling takes place under contact with a small quantity of water or with the air. In this paper, following the discussion of the effectiveness of the dry retrieval method for F1, the feasibility of the method is assessed under the different debris location assumption and time-evolving decay heat from the debris. From the analysis result, potential improvement, as well as the applicability of dry-method, will be discussed.