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The effluent water temperature of each process tube of a reactor is indicative of the operating conditions internal to that tube. A temperature monitor which will provide individual tube effluent water temperature on demand has been in use for many years in reactor operation. However, the primary sensing element, as well as other parts of the system, were not suited for installation in the No. 2 safety circuit. During the design of the K reactors, it was shown that a continuous temperature monitor could provide protection during single tube failures, except those cases wherein the flow through the tube was diminished to a very low value, provided a primary sensing element with a very short time response could be obtained. A resistance type sensing element was designed by a vendor and the continuous temperature monitor was included in the scoping of the K reactors. Although the continuous temperature monitor was approved, there were no data which showed the protection provided by such a continuous monitor. It was known that such a device would react to flow changes considerably later than the front face pressure monitor (Panellit Gages) and there was considerable doubt about the protection provided during major changes in …