TRAC Analysis of Loss-of-Fluid Test Non-Nuclear Test L1-4

To study the thermodynamic aspects of blowdown, the depressurization rate equation has been numerically solved. The equation, derived from macroscopic mass and energy balances in the pressure vessel, consisted of the energy and volumetric discharges terms multiplied by the decrease rate of residual coolant. By applying a dimensional analysis, dimensionless equations were obtained together with dimensionless parameters of blowdown. Slowdown calculations starting at typical BWR operating conditions indicated that the decrease rate of coolant increased for the liquid and two-phase mixture, and decreased for the vapor discharge. Further, the energy discharge term made a larger contribution to the depressurization rate in the case of vapor escape, while the volumetric discharge term did so in the case of liquid and two-phase mixture escape blowdowns. In the lumped model analyses, the averaged specific enthalpy and entropy of the residual coolant increased for the liquid discharge, remained almost constant for the two-phase mixture discharge, and decreased for the vapor discharge blowdown.

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“…(21) and (22) are used in the numerical analyses. The Homogeneous Equilibrium Model The pressure vessel is initially filled with water.…”

Section: Id Results and Discussionmentioning

confidence: 99%