Mrs. Dr. Xiaoyang Gaus-Liu
Research on Severe Accidents in Light Water Reactors (LWR). Investigation of the fluiddynamic, thermal and chemical processes during melt ejection out of a breach in the lower head of a LWR pressure vessel, at pressures below 2 MPa and various failure modes with an iron-alumina melt and steam.
Experiments are performed in a scaled annular cavity design, to investigate melt dispersal from the reactor pit when the reactor pressure vessel lower head fails at low system pressure of less than 2 MPa. The test facility models the reactor pressure vessel the reactor cavity, compartments and the containment. The mechanisms of efficient melt-to-gas heat transfer, exothermic metal/oxygen reactions, and hydrogen combustion produce a rapid increase in pressure and temperature in the cavity, compartments and containment. In the frame of these Direct Containment Heating (DCH) phenomena the following issues are addressed:
- final location of the melt
- loads on the containment in respect to pressure and temperature
- amount of hydrogen produced and burnt
- loads on reactor pit and support structures
- impact on safety components
Knowledge of these point can lead to realize additional safety margins for existing or new plants and help to identify appropriate accident management measures.