Temperature measuring device and reactor coolant system

The invention provides a temperature measuring device and a reactor coolant system. The temperature measuring device is applied to the reactor coolant system comprising a main pipeline, and comprises:a confluence pipeline arranged in the main pipeline, wherein the first end of the confluence pipeline is a closed end, and the second end of the confluence pipeline is an open end; at least two drainage pipes, wherein the first ends of the drainage pipes are communicated with the first end of the confluence pipeline, the second ends of the drainage pipes are connected with the pipe wall of the main pipeline, and at least two sampling holes are formed in each drainage pipe; and at least two temperature sensors, wherein the sensing ends of the temperature sensors are arranged in the confluencepipeline. According to the invention, the temperature of the reactor coolant in the confluence pipeline can be directly measured, and a temperature measurement bypass does not need to be additionallyarranged on the main pipeli