On-Line Leak Detection Method for OWL-1 Loop by ARX Modeling Using Dewpoint Signals

摘要

Model identification technique based on ARX (autoregressive model with exogenous variable) process was applied to dewpoint data recorded at OWL-1 (Oarai Water Loop No. 1) loop cubicle in JMTR (Japan Materials Testing Reactor) and the dynamical interrelationship between the supply and exhaust dewpoints in the ventilation system of the cubicle was empirically determined.It was shown that the information so derived on the dewpoint dynamics can assist to enhance the sensitivity of leak detection, if it was incorporated into a leak monitoring system for the OWL-1 loop.A simple digital filter incorporating the dewpoint dynamics was designed in an attempt to develop an efficient leak monitor for the OWL-1 loop. This filter was applied to the dewpoint data recordings during an abnormal leak that had occurred at the OWL-1 loop in the 43 rd cycle of JMTR operation, which demonstrated the effectiveness of the present method for leak detection at its early stage.