Observation of the dynamic behavior of the two-phase boundary layers in the SBLB experiments
- Pennsylvania State Univ., University Park, PA (United States)
The concept of external cooling of core melt by cavity flooding has been considered a desirable means of decay heat removal during a severe core-meltdown accident in an advanced light water reactor. In this concept, the decay heat generated in the melt is removed from the external bottom surface of the reactor vessel by downward facing boiling of water in the flooded cavity. The feasibility of this concept depends largely on the critical heat flux on the bottom surface of the reactor vessel. For the case in which the critical heat flux is higher than the local heat flux from the core melt, nucleate boiling will be the prevailing mode of heat transfer. The wall temperatures can be maintained well below the failure temperature of the steel structure. However, if the downward facing boiling situation and the thermal loading conditions are such that the local heat flux from the core melt exceeds the critical heat flux, then transition to film boiling will occur on the external bottom surface. Under such circumstances, the wall temperatures could rise rapidly toward the failure temperature of the steel structure, and the integrity of the reactor lower head could be severely jeopardized.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research
- OSTI ID:
- 54574
- Report Number(s):
- NUREG/CP--0139; CONF-9410216--; ON: TI95001469; CNN: Contract NRC-04-93-061
- Country of Publication:
- United States
- Language:
- English
Similar Records
Importance of natural convection to in-vessel melt coolability
Natural convection in a uniformly heated pool