Time Domain Reflectometry (TDR) System Application in Light Water Reactors In-Core (A Short Memorandum)

Abstract

A Time Domain Reflectometry (TDR) is not a new technology in industry. This concept has been known for its monitoring and sending of signals for the detection of cable tampering in unattended radiation detection systems. The instrument concept under investigation would allow for unmanned cable integrity measurements, remote surveillance reporting, and the locating of cable faults and/or tampering. by a national laboratory such as the Pacific Northwest National Laboratory (PNNL). TDRs are a very simple instrumentation design configuration, using pulse signals to send the pulse through the cable. Their firmness depends on the width of the pulse sent by them. That is why narrow pulse signals are preferred. However, because narrow width pulses have high frequencies, they have a limitation. High-frequency signals get distorted inside large cables. However, in this short memorandum, not only do we introduce this instrument as reminder to the readers, what this device is, we also show its application as a water level monitoring instrument by Instrumentation and Control (I&C) as an In-Core tool within the family of Light Water Reactors (LWRs) during their safe operation domain and during their commercialization as Generation-IV (GEN-IV) of Small Modular Reactors (SMRs) as a consideration among the designers and engineers of these reactors within the nuclear industry. These devices could be developed and used extensively for measuring the water level In-Core of family of LWRs as a probe for measuring such levels in reactor vessel confinement and collecting surface runoff. It could be designed, developed, and calibrated, then field-tested accordingly. This device could be used as an additional safety factor in the computation of setpoints from Probabilistic Risk Assessment (PRA), specifically if we are using such a device in new Advanced Concept Reactor (ARC) technology of SMRs of GEN-IV.