Transient tests in the PKL-test-facility (PKL III A). Vol. 1

The thermohydraulic response on the primary and secondary during transients with and without a break were investigated in the PKL Integral test facility. The results show that: isolating one, two or three of four SGs does not lead to stalling of existing steady state natural circulation in the isolated SGs; the growth of an upper plenum steam bubble during shutdown under loss of-off-site power conditions is limited to 0,3 m above the primary loops - for this reason normal shutdown procedures are not impeded by the steam bubble; the voiding of the SG-U-tubes of an isolated SG under shutdown conditions (50 K/h) interferes neither with the natural circulation flow in the intact SGs nor with the capability to depressurize the primary; the pressure drop on the secondary following injection of cold emergency feed water is also lower than expected; the RPV-level-probe responds at 90% water inventory; the result of the LOBI and PKL Counterpart test show good agreement. (orig.). 4 refs., 1 tab., 177 figs