Plant Dynamics Analysis using NETFLOW Code

Mochizuki, Hiroyasu

The NETFLOW code that can be used for liquid metal flow system has been developed on the basis of the code that can be used for a single-phase and two-phase light-water flow systems realized in pressure-tube-type reactors and LWRs. The algorithm of the code for the liquid-metal flow is developed referring to the Super System Code (SSC) in order to develop further a new code that can solve stably the thermal hydraulics with high speed. Since the electric manual of the code can be referred on a PC, one can make an input data and run on the same PC. The functions of this code were verified by individual tests for light water systems. There are a lot of experiences in applications for power plants and thermal-hydraulic experimental loops. The present report evaluates the applicability of the code and clarifies problems. Experimental examples for the evaluation are steady state test using 50 MW Steam Generator, natural circulations experiments using the PLANDTL facility, a natural circulation experiment and a turbine trip experiment of the Monju reactor.The code could generally trace these experimental results, and simulate the plant transient thermal-hydraulic behaviors of liquid metal coolant approximately 1000 times faster than the real phenomena. However, further modification should be necessary in order to improve the prediction accuracy.