What would be the first indication that a tube leak has occurred in area "23"? Illustration MO-0111

Correct Answer: Option A — The level in area "1" would decrease.

Area 23 represents the condenser section. If a tube leaks, the vacuum within the shell will be compromised as the cooling medium (typically jacket water) enters the lower-pressure vapor space. This loss of vacuum and fluid transfer causes the level in the feed water supply area 1 to decrease.