When a severe accident of a nuclear reactor occurs, decommissioning work becomes important task. In the decommissioning work of a boiling water reactor after the severe accident, estimation of the sedimentation place of the molten debris is important. However, the technique to estimate exactly the sedimentation place has not been enough developed. Therefore, the detailed and phenomenological numerical simulation code named “JUPITER” is under development for predicting the molten core behavior in JAEA (Japan Atomic Energy Agency). The comparison between experimental and numerical results is necessary to clarify the validity of the numerical analysis code. The study provides the experimental data to examine the numerical simulation code. As a basic study to examine the numerical simulation code, a liquid film flowing in a modeling flow channel was studied by using water. The flow was visualized, and the flow data were obtained by image processing.

When a severe accident occurs, decommissioning work becomes important task. In the decommissioning work after the severe accident, establishing the way to estimate the sedimentation place of molten debris is important. However, the technique to estimate exactly sedimentation place has not been enough. Therefore, the detailed and phenomenological numerical simulation code named JUPITER for predicting the molten core behavior is under development. The comparison between experimental and numerical results is necessary to clarify the validity of the numerical analysis code. This study provides the experimental data for a BWR to examine the numerical simulation code in order to contribute to progress of the decommissioning work.