explain phenomena occurring before tube leakage

[cstron]

I observed in our 500MW boilers prior to tube leakage,ammonia level in feed water and sat. steam is raising by 0.2ppm i.e from 0.45 (normal) to around 0.55 to 0.65 ppm. Explain how is this possible.

 

[vsvenkat7]

It is most probably that the increased ammonia level caused the tube failures and not otherwise. I have observed this phenomenon in low pressure steam line in a ammonia plant - though I am not sure about the exact mechanism that causes this failure.