Based on cavitation margin during the time of normal operation and load-rejecting test for the turbine driven feed-water pump and its booster pump of one ultra-supercritical 1 000 MW unit

the safety margin of feed-water system for said unit under different operating conditions has been analysed

and preventive measures for cavitation occurred in the booster pump under adversed operating condition have been put forward as in the following:in design

enhancing the elevation of deaerator

improving the structure of booster pump

and reducing the pressure loss in downcomer tube etc.

as well as in operation

rapidly putting the stand-by heating steam source of the deaerator into service

reducing the decrease speed and magnitude of pressure in the deaerator

and slowing the decrease of inlet pressure for booster pump etc..