TWO-PHASE CRITICAL FLOW WITH APPLICATION TO LIQUID-METAL SYSTEMS (MERCURY, CESIUM, RUBIDIUM, POTASSIUM, SODIUM, AND LITHIUM)

Existing data and models for critical two-phase flow of steam-- water mixtures are examined. One model in particular shows considerable success in predicting the phenomena of critical flow. A Fortran program for an IBM-704 digital computer, for the application of this model to predict void fraction, slip ratio, and critical flow rates to the flashing flow for various liquid-vapor metal systems inpipes when the conditions are such that critical flow may be experienced, was developed. Calculations were made for the following liquid- metal systems: mercury (temperature range, 450 to 1600 deg F), cesium (temperature range, 500 to 2300 deg F), rubidium (temperature range, 500 to 2300 deg F), potassium (temperature range, 900 to 2500 deg F), sodium (temperature range, 950 to 2500 deg F), and lithium (temperature range, 2000 to 3500 deg F). The vapor fraction or quality ranges from 0 to 100%. It is shown that the critical flow rates for liquid-metal systems calculated from the best model describing steam--water data are considerably higher in the low-quality region than predicted from a socalled homogeneous flow model.'' This is explained by the large slippage between the liquid and the vapor phases, because the ratio of the densities of the liquid state to the vapor state is usually large for metallic fluids. (auth

Generic considerations of LMFBR hypothetical accident energetics

The paper provides a preliminary assessment of generic accident energetics issues associated with alternatives relative to the reference (U,Pu) oxide fuel in liquid metal fast breeder reactors. The alternatives considered include thorium- and uranium-based oxide, carbide and metal fuel types. This assessment is made within the context of low probability, but potentially large consequence accidents, e.g., core-disruptive accidents

A STUDY OF THE FLOW OF SATURATED FREON-11 THROUGH APERTURES AND SHORT TUBES

An experimental study on the discharge rates of saturated and subcooled Freon-11 through apertures and short tubes is reported. The experiment covered a range of modified cavitation numbers between 0 and 500, length-to-diameter ratios of small-diameter tubes between 2 and 55, and sharp-edge apertures of nine different geometric configurations. It was found that below the modified cavitation number of 10, the iluid exhibits completely metastable singlephase ilow. When the modified cavitation number exceeds 14, two-phase critical flow may exist. In the range of modified cavitation numbers between 10 and 14, unstable transitional flow occurs (alternating single- and twophase flow). Euler numbers for the apertures of various configurations, including square, rectangular, and eyeshaped, were found to be in the same order of magnitude as those for circular shapes. The trianguiar orifices were found to possess higher Euler numbers and the Wshaped orifices lower than the circular ones. (auth

Safe venting of ``red oil`` runaway reactions

Calorimetry testing of Tri-n-butyl phosphate (TBP) saturated with strong nitric acid was performed to determine the relationship between vent size and pressure buildup in the event of a runaway reaction. These experiments show that runaway can occur in an open system, but that even when runaway is induced in the TBP/HN0{sub 3} system, dangerous pressure buildup will be prevented with practical vent size

Ferrocyanide Safety Program: Waste tank sludge rheology within a hot spot or during draining. Homogeneous flow versus flow through a porous medium

The conditions under which ferrocyanide waste sludge flows as a homogeneous non-Newtonian two-phase (solid precipitate-liquid) mixture rather than as a liquid through a porous medium (of stationary precipitate) are examined theoretically, based on the notion that the preferred rheological behavior of the sludge is the one which imposes the least resistance to the sludge flow. The homogeneous two-phase mixture is modeled as a power-law fluid and simple criteria are derived that show that the homogeneous power-law sludge-flow is a much more likely flow situation than the porous medium model of sludge flow. The implication of this finding is that the formation of a hot spot or the drainage of sludge from a waste tank are not likely to result in the uncovering (drying) and subsequent potential overheating of the reactive-solid component of the sludge