A Study on the Coolant Mixing Phenomena in the Reactor Lower Plenum

  • 발행 : 1997.06.01

초록

When asymmetric thermal-hydraulic conditions occur between cold legs, the core inlet temperature will be nonuniform if the coolant is not mixed perfectly in the lower plenum. These uneven core inlet conditions may induce the change in core power distribution. Thus realistic prediction of thermal mixing is important in such abnormal conditions. In this study, reactor internals, which are scaled down as to conserve the flow area ratio, are set up in the model of KORI Unit 1 with the scaling factor of 1/710 by volume and coolant temperatures are measured beneath the lower core plate. Based on experimental results, the ability of COMMIX-1B code to simulate the coolant mixing phenomena in the lower plenum is estimated. The results show that complete mixing never occurs in any conditions and the mixing pattern is characterized according to the plant type.

키워드

참고문헌

  1. EPRI NP-3545 Thermal Mixing in the Lower Plenum and Core of a PWR J.H. Kim
  2. EPRI NP-3780 Analysis of Oconee Unit 1 Downcomer and Lower Plenum Thermal-Mixing Tests Using COMMIX-1A L.H. Kim
  3. M.S. Thesis, SNU. An Experimental Study on Natural Circulation in a UTSG PWR K.H. Kim
  4. Fluid Mechanics(2nd edition) F.M. White
  5. Handbook of Product Manual Analog Device
  6. Visualization of the Lower Plenum Anomaly in the Westinghouse AP600 Reactor T.D. Radcliff;W.S. Johnson;J.R. Parsons;D.E. Ekeroth
  7. NUREG/CR-4348, ANL-85-42 COMMIX-1B: A Three-Dimensional Transient Single-phase Computer Program For Thermal Hydraulic Analysis Of Single And Multicomponent Systems W.T. SHA(et al.)