Water Simulation of Sodium Reactors

Abstract

The thermal hydraulic simulation of a large sodium reactor by a scaled water model is examined. The Richardson Number, friction coefficient and the Peclet Number can be closely matched with the water system at full power and the similarity is retained for buoyancy driven flows. The simulation of thermal-hydraulic conditions in a reactor vessel provided by a scaled water experiment is better than that by a scaled sodium test. The results from a correctly scaled water test can be tentatively extrapolated to a full size sodium system.

Ultrasonic thermometry simulation in a random fluctuating medium: Evidence of the acoustic signature of a one-percent temperature difference

“…Fiorina [10,11] studied this issue and used a ray-tracing code and a Gaussian beam summation method to perform wave propagation simulation and compared amplitude and time of flight fluctuations with known analytical results. Similarities between water and sodium have been well described [12] and it is thus possible to reproduce liquid sodium behavior with hot water experiments. Fiorina [10,11] represents the fluctuating medium by a homogeneous and isotropic turbulent medium: temperature spatial fluctuations are considered in the stochastic domain and modeled by a Fourier mode summation technique.…”

“…Characteristic sizes of flow heterogeneities, typically ranging between 0.1 cm and 10.0 cm, are also large compared to the wavelengths of the ultrasonic waves considered [12].…”

“…As stated above the propagation medium is in a turbulent state and its temperature distribution varies in a complicated fashion both in space and in time between, inside and above the assembly edges. Buffet [32], Fiorina [10] and Lü [12] have studied wave propagation in a turbulent liquid metal flow and, regarding sound velocity in such a medium, have decomposed the medium into two parts: a heterogeneous static part, and a random fluctuation part caused by the turbulent flow. In our study we will first perform simulations in the presence of a static temperature distribution only, and then in a second step with temperature fluctuations in the whole propagation region, generated based on a Gaussian random field.…”

Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems

“…By the non-dimensionalization of the appropriate equations one may derive the necessary conditions for exact similitude. Grewal & Gluekler ( 1982 ) have shown that in order that an experimental model represent an exact similitude of the LMFR pler,,a it is essential that:…”

Thermalhydraulic aspects of decay heat removal by natural circulation in fast reactor systems. Final report

“…axi =k axiaxi _xi_]. ui j+ "_T(6) =mm In these equations the overbars represent averaged quantities and the index on the left superscript signifies the coordinate direction in which the summation convention does not apply. The left superscript "v" signifies volume-averaged quantities.This set of equations is no longer a closed set -due to the non-linearities in the governing equations _ -the averaging process gives rise to second order correlations that must be modeled,.…”