Simulation of thermal phenomena expected in fuel coolant interactions in LMFBRs
High pressures and mechanical work may result when thermal energy is transferred from molten fuel to the coolant in a Liquid Metal Fast Breeder Reactor core meltdown accident. Two aspects of the interaction are examined in the thesis. First, the formation of high pressure pulses termed ''Vapor Explosions,'' and second, the distribution of the molten material into smaller particles, termed ''Fragmentation'', are studied. To understand the nature of the interaction simulant materials were used. Molten bismuth, molten tin and molten glass were dropped into water under various conditions. The interactions were recorded using multiflash and high speed photographing techniques. The pressure pulses were measured using transducers and the debris was examined by photographing them with an electron microscope. It was observed that vapor explosions have thresholds which depend on the material being dropped, its temperature and the bath conditions. The vapor explosions were enhanced by stratifying the bath. It was also noticed that the intensity of the vapor explosion depends on the way the molten drop fragmented in the initial stages of the interaction. The experiments with glass showed that the mode of fragmentation is important in determining when and if a vapor explosion is to be expected. The glass fragmented extensively but without any accompanying vapor explosion. The electron microscope photographs of the glass debris showed that thermal stress and surface tension phenomenon are apparently the cause of the fragmentation.
- Research Organization:
- California Univ., Los Angeles (USA). Dept. of Energy and Kinetics
- OSTI ID:
- 7270415
- Report Number(s):
- NUREG-0187; UCLA-ENG-76100
- Country of Publication:
- United States
- Language:
- English
Similar Records
An experimental study of the molten glass/water thermal interaction. Topical report. [LMFBR]
Fuel coolant thermal interaction project. Quarterly progress report No. 4, April 1, 1976--June 31, 1976. [LMFBR]
Related Subjects
210500 -- Power Reactors
Breeding
22 GENERAL STUDIES OF NUCLEAR REACTORS
220900* -- Nuclear Reactor Technology-- Reactor Safety
ACCIDENTS
BREEDER REACTORS
EPITHERMAL REACTORS
EXPLOSIONS
FAST REACTORS
FBR TYPE REACTORS
FRAGMENTATION
FUEL-COOLANT INTERACTIONS
LIQUID METAL COOLED REACTORS
LMFBR TYPE REACTORS
MELTDOWN
MOLTEN METAL-WATER REACTIONS
REACTOR ACCIDENTS
REACTORS
SIMULATION