Analysis of secondary side oriented accident-management measures for a PWR of KWU-design

Secondary side oriented human-based accident management (AM) measures for events with multiple failures of safety systems as an alternative to primary side oriented measures (e.g. primary bleed and feed) is described. It is demonstrated that the secondary bleed and feed measures have the capability of preventing core melt even in fast transients, e.g. the total loss of feedwater transient. In this case, a rough estimate of the necessary operator actions shows the feasibility of the AM measure. It is also shown that the use of the feedwater tank inventory makes possible a sufficient depressurization of the reactor pressure vessel to reach the operating range of low pressure injection pumps for further reactor cooling before the feedwater tank is emptied and the secondary heat removal fails again.<>