New Approach for the Root Cause of Fukushima Meltdown Accident

The purpose of this Commentary is to clarify as much possible the whole history reactor and containment pressure changes in Fukushima meltdown accident. It based on a new approach for film boiling, which kept after Zr-H2O reactions. Most important point that author applied boiling curve, basic theory phenomena, accident phenomena. As reaction rate proportional or under it increases rapidly stops suddenly, keeping boiling. change consists three phases, namely pressurizing, high de-pressurizing. pressurized by H2 gas steam produced reactions de-pressurized heatsink such wall inner shield concrete stops. between these balancing with leaked from gap top lid containment. Core decay heat large, but its negligibly small. So, pressurization calculated Zr- H2O balances during condition. de-pressurization occurs over, so can be heatsink, equal condensation de-pressurization. leak using rate. very rection slowed insufficient supply, melted cores were covered (film boiling) at 0.8MPa lower pressure. This different (at approx. 7MPa) Three Mile Island accident, specific volume 0.8 MPa ten times larger than 7 MPa. calculation results assumption show almost all Zr each core Units 1, 2 3 reacted water.