This is an early document. Click to view the entire page. Core exit thermocouples have survived as a primary warning of core uncovering. In the case of LOFT experiment L2-5, core exit thermocouples severely misled the plant operators.
And here is a the related analysis from Oak Ridge National Laboratory:
And, here is a detailed analysis by ORNL:
Here is the cover page and one paragraph from page 81. In general, the report supports HJTCs as monitors of inadequate core cooling.