Flow condition monitor

A flow condition monitoring system for monitoring fluid flow conditions in a nuclear power plant comprising:

• a first sensor assembly comprising a laser beam transmitter and receiver for detecting optical characteristics in the fluid flow, and
• a database containing known optical characteristics of the various fluid flow conditions being monitored;
• and
• a processor means connected to said first sensor assembly and to said database for receiving and comparing the signal from the sensor assembly with the known characteristics contained in the database to determine a condition of the fluid flow.

A flow condition monitoring system for monitoring the coolant flow in a shutdown cooling system drain pump of a nuclear power plant during midloop operation, comprising:

• a main pipe to conduct coolant from a nuclear reactor to a steam generator, said main pipe being substantially horizontal and having an upper region and a lower region;
• a drain pipe connected at the lower region of the main pipe to conduct coolant from the lower region to a drain pump;
• a first sensor assembly positioned near the drain pipe for detecting acoustic signals from a coolant flow within the drain pipe;
• a database of known acoustic signal characteristics of various flow conditions being monitored;
• and
• a processor that compares the detected acoustic signals with the known acoustic characteristics contained in the database to identify a coolant flow condition.

A method of monitoring flow conditions in a nuclear power plant, comprising the steps of:

• positioning a first sensor assembly near a fluid flow to be monitored;
• generating a first output signal by said first sensor assembly indicative of a fluid flow condition;
• providing a database containing known output signal characteristics of various fluid flow conditions being monitored;
• and
• comparing said first output signal with the known characteristics of various fluid flow conditions to identify the fluid flow condition.