[2K16-20] Fukushima Daiichi NPP Accident 2

[2K18] Development of Evaluation Method for Air Cooling of Fuel Debris

(2)Preliminary analysis of the natural convection cooling performance

*Susumu Yamashita¹, Shinichiro Uesawa¹, Hiroyuki Yoshida¹ (1.Japan Atomic Energy Agency)

Keywords:numerical simulation, fuel debris, air cooling, natural convection

In the way of fuel debris retrieval on decommissioning of the Fukushima daiichi nuclear power stations, the submersion and in-air retrieval have been considered. In the in-air retrieval, because fuel debris is taken away in air, investigations of the possibility of the air cooling of fuel debris will be very important issue for realizing that method. However, fuel debris shape and surface temperature have much uncertainties and in order to evaluate the possibility of air cooling of fuel debris, we have to understand the cooling mechanism of a natural convection which is affected by the characteristics. Therefore, in order to evaluate the possibility of in-air cooling of fuel debris, we have been performing experimental and analytical studies regarding the understanding of the phenomenon. In this report, we will present the research plan and also present evaluation results as preliminary analysis, which are heat transfer coefficient from fuel debris to air in simplified system.