A Simple method for estimating the structure temperatures and the cesium revaporization inside the reactor pressure vessel, 2; Feasibility study for the Fukushima Daiichi Nuclear Power Plant

Liu, Q.; Ishikawa, Jun ; Maruyama, Yu ; Watanabe, Norio

This work examines the feasibility of the method proposed in the preceding part of a two-part paper. The base case study shows that water injection via the core spray line is more effective to cool the uncovered core and to reduce the release of CsOH. Sensitivity study is conducted by introducing the dimensionless decay heat, which combines the effects of the ratio of the flooded core, the ratio of the slumped core and the leak ratio of the injected water on the steam generation rate associated with the forced convection cooling in the reactor pressure vessel (RPV). The results show that the temperatures of the uncovered core and the other structures increase with the dimensionless decay heat. So does the release rate of CsOH. The relationships of the measurable RPV wall temperature with the temperatures of the uncovered core and the other structures as well as the release characteristics of CsOH are also examined in this work.