Occurrence of critical heat flux during blowdown with flow reversal. [PWR]

Technical Report · Sat Jan 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/7292819· OSTI ID:7292819

Leung, J C.M.

A small-scale experiment using Freon-11 at 130/sup 0/F (54.4/sup 0/C) and 65 psia (0.45 MPa) in a well-instrumented, transparent annular test section was used to study the occurrence of critical heat flux (CHF) during blowdown with flow reversal. The inner stainless steel tube of the annulus was uniformly heated over its 61-cm length. Inlet and exit void fractions were measured by a capacitance technique. Flow-regime transition was observed with high-speed photography. A 1-hr contact time between Freon-11 and nitrogen at 130/sup 0/F (54.4/sup 0/C) and 60 psig (0.517 MPa) was found to greatly affect the steady-state subcooled-boiling initial conditions. Delay in bubble growth was observed in adiabatic blowdown runs. This was caused by the conditions of thermodynamic nonequilibrium required for the unstable bubble growth. For the diabatic runs, equilibrium was more closely approached in the test section during the early phase of blowdown.

• Research Organization: Argonne National Lab., Ill. (USA)
• Sponsoring Organization: U.S. Nuclear Regulatory Commission
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7292819
• Report Number(s): ANL-77-4
• Country of Publication: United States
• Language: English

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ACCIDENTS
BLOWDOWN
CRITICAL HEAT FLUX
FLOW RATE
FLUID FLOW
HEAT FLUX
HYDRAULICS
LOSS OF COOLANT
MOCKUP
PERFORMANCE TESTING
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REACTOR ACCIDENTS
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SIMULATION
STRUCTURAL MODELS
TEMPERATURE GRADIENTS
TESTING
TWO-PHASE FLOW
VOID FRACTION
WATER COOLED REACTORS
WATER MODERATED REACTORS