The pool only needs to function for a few days during/after an accident until heat energy from fission product decay reduces to lower levels. The pool's functi

The pool only needs to function for a few days during/after an accident until heat energy from fission product decay reduces to lower levels. The pool's function is as an accident mitigation measure - and when any accident occurs the reactor enters a "shut down" state. The decay heat energy that needs to be dissipated is much lower than normal reactor operational power output.