Patent Number: 
Section: claims

1. A nuclear reactor system comprising:a reactor vessel;a nuclear core including a plurality of nuclear fuel assemblies housed within the reactor vessel and configured to be immersed within a reactor coolant, the fuel assemblies structured to heat the reactor coolant;a primary coolant loop piping system configured to be in fluid communication with a heat utilization mechanism and the reactor vessel for conveying the reactor coolant between the reactor vessel and the heat utilization mechanism and back to the reactor vessel;an auxiliary piping system in fluid communication with the primary coolant loop piping system and being configured to add or extract reactor coolant to or from the primary coolant loop piping system;an acoustic transmitter acoustically coupled to a first location on an outer surface of either the primary coolant loop piping system or the auxiliary piping system and configured to transmit an acoustic pulse through the reactor coolant;an acoustic receiver acoustically coupled to a second location on an outer surface of the either of the primary coolant loop piping system or the auxiliary piping system that is substantially diametrically opposed to the first location, with the acoustic receiver configured to receive the acoustic pulse;a flow meter configured to measure a speed of the reactor coolant within the either of the primary coolant loop piping system or the auxiliary piping system and provide an output indicative thereof;a boron concentration meter configured to measure a boron concentration in the reactor coolant and provide an output indicative thereof; andan acoustic control system connected to the acoustic transmitter and the acoustic receiver, wherein the acoustic control system is configured to:receive a first output from the flow meter;receive a second output from the boron concentration meter; anddetermine a temperature of the reactor coolant based on:a time lag between a transmission of the acoustic pulse at the acoustic transmitter and a receipt of the acoustic pulse at the acoustic receiver;the output of the flow meter; andthe output of the boron concentration meter. 2. The nuclear reactor system of claim 1 including:a second acoustic transmitter acoustically coupled to a third location on the outer surface of the either of the primary coolant loop piping system or the auxiliary piping system and configured to transmit a second acoustic pulse through the reactor coolant;a second acoustic receiver acoustically coupled to a fourth location on the outer surface of the either of the primary coolant loop piping system or the auxiliary piping system that is substantially diametrically opposed to the third location, with the acoustic receiver configured to receive the second acoustic pulse; andwherein the acoustic control system is also connected to the second acoustic transmitter and the second acoustic receiver and is configured to determine a second time lag between a transmission of the second acoustic pulse at the second acoustic transmitter and the receipt of the second acoustic pulse at the second acoustic receiver and correlate the second time lag to a temperature of the reactor coolant. 3. The nuclear reactor system of claim 1 wherein the acoustic pulse is an ultrasonic pulse. 4. The nuclear reactor system of claim 1 wherein the either of the primary coolant loop piping system or the auxiliary piping system is a hot leg of the primary coolant loop piping system. 5. The nuclear reactor system of claim 1 wherein the either of the primary coolant loop piping system or the auxiliary piping system is a cold leg of the primary coolant loop piping system. 6. The nuclear reactor system of claim 1 wherein the acoustic transmitter and the acoustic receiver comprise solid state vacuum micro-electronic devices. 7. The nuclear reactor system of claim 1 further including a thermoelectric generator having a hot junction in thermal communication with a wall of the either of the primary coolant loop piping system or the auxiliary piping system, and wherein the acoustic transmitter and the acoustic receiver are powered by the thermoelectric generator. 8. The nuclear reactor system of claim 1 wherein the transmitted pulse of the acoustic transmitter and the output of the acoustic receiver are connected to a wireless transmitter and the transmitted acoustic pulse from the acoustic transmitter and the output of the acoustic receiver are wirelessly transmitted to the acoustic control system. 9. The nuclear reactor system of claim 8 wherein the wireless transmitter comprises solid state vacuum micro-electronic devices. 10. The nuclear reactor system of claim 1 wherein the transmitted acoustic pulse is a continuous stream of pulses.