Abstract
New BWR core monitoring system "GNF-ARGOS" has been applied to the Japan Atomic Power Company Tokai No.2 power station. ARGOS incorporated a BWR core physics simulator AETNA to evaluate the core performance. ARGOS is the world first system that adopted the three neutron energy group core simulator for on-line BWR core monitoring. With instrument adaption and reconstructed pin powers, ARGOS can provide accurate information on the whole core pin-by-pin thermal margins. Currently the official core monitor of Tokai No.2 power station is 3D-Monicore system. ARGOS is planned to be an official monitor after validation during parallel run with the current system. During the startup operation in cycle 25, verification of ARGOS system was done by comparing the fraction of limiting CPR (FLCPR) and the fraction of limiting power density (FLPD), as well as the axial power distribution to those obtained with 3D-Monicore system. Cold critical eigenvalues were tested against the measurements. Also, comparisons are made for the core prediction during the startup with the monitoring results. It is concluded that the agreements are good and thus the ARGOS results are acceptable.
