A fuel freezing model for liquid-metal fast breeder reactor hypothetical core disruptive accidents

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Nucl. Sci. Eng.; (United States)

OSTI ID:6308742

Best, F R; Erdman, C; Wayne, D

A proposed fuel freezing mechanism for molten UO2 fuel penetrating a steel channel was investigated in the course of liquid-metal-cooled fast breeder reactor hypothetical core disruptiv accident safety studies. The fuel crust deposited on an underlying melting steel wall was analyzed as being subjected to two stresses one due to the pressure difference between the flowing fuel and the stagnant molten steel layer, and the other resulting from the temperature variation through the crust thickness. Analyses based on the proposed freezing mechanism and comparisons with fuel freezing experiments confirmed that fuel freezing occurs in three modes. For initially low steel wall temperatures, the fuel crust was stable and grew to occlude the channel. At high steel wall temperatures (above 1070 K), instantaneous wall melting leading to steel entrainment was calculated to occur with final penetration depending on the refreezing of the entrained steel. Between these two extremes, the stress developed within the crust at the steel melting front exceeds the critical buckling value, the crust ruptures, and steel is injected into the fuel flow. Freezing is dominated by the fuel/steel mixture. The theoretical penetration distances and freezing times were in good agreement with the experimental results with no more than 20% error involved.

• Research Organization: Texas AandM University, Nuclear Engineering Department, College Station, TX
• OSTI ID: 6308742
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 89:1; ISSN NSENA
• Country of Publication: United States
• Language: English

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ACCIDENTS
ACTINIDE COMPOUNDS
ALLOYS
BREEDER REACTORS
CHALCOGENIDES
CONTAINERS
ENERGY TRANSFER
EPITHERMAL REACTORS
FAST REACTORS
FBR TYPE REACTORS
FEASIBILITY STUDIES
FLUID MECHANICS
FLUID-STRUCTURE INTERACTIONS
FREEZING
HEAT TRANSFER
HYDRAULICS
IRON ALLOYS
IRON BASE ALLOYS
LIQUID METAL COOLED REACTORS
LMFBR TYPE REACTORS
MATHEMATICAL MODELS
MECHANICS
MELTDOWN
OXIDES
OXYGEN COMPOUNDS
PRESSURE EFFECTS
PRESSURE VESSELS
REACTOR ACCIDENTS
REACTOR COMPONENTS
REACTOR CORE DISRUPTION
REACTOR CORES
REACTOR SAFETY
REACTORS
SAFETY
STEELS
STRESSES
TEMPERATURE EFFECTS
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES