Radcal-Based Reactor Vessel Monitoring System for Inadequate Core Cooling Determination

Technology for Energy Corporation, Scandpower, Incorporated, and Arkansas Power & Light Company have developed jointly a system for monitoring the coolant status within a reactor vessel during loss-of-coolant accidents. The sensor portion of the system is based on a heated thermocouple probe called Radcal and is used to monitor coolant inventory and temperature above the reactor core and heat transfer conditions and shutdown power within the core. The Radcal was originally developed and tested in reactor as a local fuel power instrument by a group of eight U.S. and European utilities and had 400 sensor years of excellent performance experience at the time the vessel monitoring system development began. Extensive testing during simulated loss-of-coolant accidents has detnonstrated the ability of the Radcal probe to track coolant conditions under a wide range of simulated small break accidents. The first installation of this system will be at the Arkansas Power & Light Company's ANO Unit 2 reactor.