What triggers a both MFP trip?

A trip of both main feed pumps (MFP) is triggered when there is a significant issue that could compromise the integrity of the pumping operations. Among the choices, the option indicating that all condensate pump trips lead to a trip of both MFPs is correct because the condensate pumps play an essential role in maintaining the water supply for the feedwater system. If the condensate pumps trip, it indicates that there is a failure in the return cycle of the steam cycle, which would affect the supply of water to the boilers. Without adequate condensate return, the feedwater system would not operate efficiently or safely, necessitating the shutdown of both main feed pumps to prevent further operational issues and ensure system safety.

The low lube oil temperature impacts the lubrication and cooling of pump components but does not directly trip both MFPs. High feed pump suction pressure may indicate an operational issue but wouldn’t inherently cause a trip of both pumps. Lastly, a low steam flow rate may signal issues in steam production or demand but does not necessarily affect the operation of both MFPs in a way that would require them to trip simultaneously. Hence, the relationship between the condensate pumps and the feed pump operation makes that option the most relevant.