Apparatus with flow assembly including temperature sensors and heating element

1. An apparatus within a nuclear reactor, comprising:

a flowmeter assembly configured to be coupled to at least one surface such that the flowmeter assembly is exposed to at least one first portion of a flow channel, the flowmeter assembly being configured to monitor a flow of a coolant fluid in the at least one first portion of the flow channel, the flowmeter assembly including

a first temperature sensor configured to generate first temperature data based on measuring a first temperature of a first flowstream of the coolant fluid in the at least one first portion of the flow channel;

a heating element directly coupled to the first temperature sensor at an interface of the first temperature sensor such that the heating element is configured to apply heat to the first temperature sensor through the interface;

a second temperature sensor configured to generate second temperature data based on measuring a second temperature of a second flowstream of the coolant fluid in the at least one first portion of the flow channel, the first flowstream and the second flowstream running parallel to each other within the at least one first portion of the flow channel, the second temperature sensor being spaced apart from the heating element, and the second temperature sensor being at least partially insulated from the heating element so that the second temperature data generated by the second temperature sensor is independent of heat generated by the heating element; and

a control system including a memory and a processor, the memory storing non-transitory computer-readable instructions, the processor configured to read the non-transitory computer-readable instructions in order to

calculate a flowrate of the coolant fluid in the at least one first portion based on the second temperature data and a temperature of the coolant fluid.

2. The apparatus of claim 1 , wherein the first and second temperature sensors are configured to be exposed to a common flowstream.

3. The apparatus of claim 1 , wherein the flowmeter assembly includes insulating material in order to at least partially insulate the second temperature sensor so that the second temperature data generated by the second temperature sensor is independent of heat generated by the heating element, the insulating material being packed around the heating element and at least a portion of the first temperature sensor.

4. The apparatus of claim 1 , wherein the flowmeter assembly includes,

at least one third temperature sensor, the at least one third temperature sensor being configured to generate third temperature data based on measuring a third temperature of at least one flowstream of the coolant fluid in the flow channel, the at least one third temperature sensor being at least partially insulated from the heating element.

5. The apparatus of claim 4 , wherein the at least one third temperature sensor and the second temperature sensor are configured to be exposed to at least one of

axially-separated portions of the flow channel, relative to a longitudinal axis of the flow channel; and

azimuthally-separated portions of the flow channel, relative to the longitudinal axis of the flow channel.

6. The apparatus of claim 1 , further comprising: a flow channel cover configured to at least partially define the first flowstream and the second flowstream.

7. The apparatus according to claim 1 , wherein the processor is further configured to calculate the flowrate by

determining a first heat flux at the second temperature sensor based on the temperature of the coolant fluid and the second temperature data,

determining a second heat flux at e first temperature sensor based on the temperature of the coolant fluid, the first temperature data, and a first surface area of the interface, and

calculating the flowrate based at east one on the first heat flux and the second heat flux.

8. The apparatus of claim 7 , wherein the processor is further configured to calculate the flowrate by

determining a heat transfer rate through the first surface area based on an electrical current being sent to the heating element,

determining an equivalent heat transfer coefficient at the second temperature sensor, and

calculating the flowrate based further on the heat transfer rate and the equivalent heat transfer coefficient.

9. The apparatus of claim 7 , wherein the flowmeter assembly further includes insulating material between the first temperature sensor and the heating element, the insulating material being configured to insulate the first temperature sensor from the heating element.

10. The apparatus of claim 1 , further comprising:

a dummy heating element directly coupled to the second temperature sensor, the dummy heating element having a same mass and thermal environment as compared to the heating element, wherein the dummy heating element is configured to not emit heat.

11. The apparatus of claim 10 , wherein

the heating element is positioned downstream of the first temperature sensor, relative to a direction of the flow of the coolant fluid in the first flowstream, and

the dummy heating element is positioned downstream of the second temperature sensor, relative to a direction of the flow of the coolant fluid in the second flowstream.

12. The apparatus of claim 1 , wherein the heating element is positioned downstream of the first temperature sensor, relative to a direction of the flow of the coolant fluid in the first flowstream.

13. The apparatus of claim 1 , wherein the second temperature sensor is spaced apart from the first temperature sensor in a first direction that is perpendicular to a second direction of the flow of coolant fluid of the at least one first portion of the flow channel.

14. The apparatus of claim 13 , wherein the heating element is positioned downstream of the first temperature sensor, relative to a direction of the flow of the coolant fluid in the first flowstream.