Frequent copper tube leakage had occurred in oil-cooler of steam turbines during operation period from Feburary

2004 to June

2006 at Yuelong Power Generation Co Ltd.For this

a series of analysis has been carried out from aspects

such as material quality of copper tubes

water quality of cooling water

oil quality of turbine oil

and shutdown(standby) mode etc.

finding out the main causes resulting in corrsion and leakage of the copper tubes to be as follows:(1) the quality of copper tube materials isn't suitable for the quality of cooling water;(2)the shutdown(standby) mode is improper.Thereby

the copper tubes BFe10-1-1 of oil-cooler have been replaced by using stainless steel tubes

and the shutdown(standby) mode being improved

making the said problem finally to be solved.