Patent ID: 6456681
Filing Date: 2002-09-24
Classification: G21C,Y02E

Abstract:
A neutron flux measuring apparatus, adapted to a boiling-water reactor (BWR) of a nuclear power plant and an advanced boiling-water reactor (ABWR) of a nuclear power plant, for measuring a neutron flux in a reactor pressure vessel, said neutron flux measuring apparatus comprising:a plurality of neutron flux detector assemblies each incorporating a start-up range monitor detector, each of said plurality of neutron flux detector assemblies comprising a local power range monitor detector, a start-up range neutron monitor detector, calibrating means for calibrating sensitivity of said local power range monitor detector and a cover tube incorporating the local power range monitor detector, the start-up range neutron monitor detector and the calibrating means; a plurality of neutron flux detector assemblies each comprising said local power range monitor detector, said calibrating means and said cover tube; a preamplifier amplifying a detector signal obtained from said start-up range neutron monitor detector; a start-up range neutron monitor operation unit operating, indicating and monitoring the amplified signal obtained from said start-up range neutron monitor detector; a local power range monitor operation unit operating, indicating and monitoring a signal obtained from said local power range monitor detector; and an average power range monitor operation unit averaging, indicating and monitoring signals obtained from a plurality of local power range monitor detectors; where the start-up range neutron monitor detector, distinct from the local power range monitor detector, is configured to measure neutron flux in the reactor pressure vessel in a low power range operation of the reactor pressure vessel, and where the local power range monitor detector, distinct from the start-up range neutron monitor detector, is configured to measure neutron flux in the reactor pressure vessel in a high power range operation of the reactor pressure vessel.