A Gamma-Ray Attenuation Method for Void Fraction Determinations in Experimental Boiling Heat Transfer Test Facilities

Abstract

Gamma rays emanating from a radioactive source are beamed through and are attenuated by steam-water mixtures contained in a simulated reactor flow channel. The emergent radiation is detected by a scintillation crystalphotomultiplier tube assembly. An expression is developed which yields the void fraction when the detector output with the channel empty, filled with water, and containing the mixture in question, is known.

A study of one- and two-component, two-phase critical flows at low qualities

“…In Ref. 20 The above formulation is permissible for small errors. However, when the errors become large it will produce error magnitudes that are not characteristic of the system.…”

Summary on experimental methods for statistical transient analysis of two-phase gas-liquid flow. [BWR, PWR, and LMFBR]

“…Unfortunately, two-phase flow is neither stationary nor homogeneous. Effects due to lack of homogeneity in the form of parallel layers of gas and liquid oriented parallel to the photon beam were discussed by Hooker and Popper 48 and verified by Petrick and Swanson 86 who showed that errors as high as 40% could be possible. These errors are due to "photon streaming" preferentially through the gas such that the emergent attenuation is the sum of two separate exponentials rather than the exponential of the sum of two linear terms.…”

On the Measurement of the Dynamic Properties of the Steam Void Fraction in Boiling Water Channels

“…According to the previously mentioned references, (19)(20)(21) the relation between the output signal i(t) of the current amplifier and the steam void fraction a(t) can be expressed as…”

“…It is known that the expectation value of an exponential is given by /exp z\ = exp(z + y a| ) (20) when z is Gaussian. From (20) …”