The main purpose of the experimental study is to demonstrate capability of decay heat removal, to determine behavior of the system and components, to find start-up characteristics and procedures and to obtain a database for developing computer codes for AC600/1000 passive emergency residual heat removal system.

The total 166 sets of experimental data are identified. The test results illustrate that short disturbances of wind speed, power and valve opening have no significant impact on natural circulation flow, implying that the system seems to tolerate these disturbances. A correlation of two-phase, natural circulation flow rate is derived from constitutive equations by use of lumped system parameters were obtained. The empirical coefficients m and n were obtained by non-linear regression of 83 test data. Compared with 166 sets of the measured data, the deviation of 98.8% of the data points is within ±15%.

It is noted from transient research that AC600/1000 ERHR system is able to remove decay heat. Three start-up modes are available to trigger natural circulation flow. Computer code ERHRAC simulating natural circulation flow characteristics of ERHRS for AC600/1000 has been developed based on the test data.