In-Core Neutron Flux Measurements at PARR Using Self Powered Neutron Detectors

摘要

The report describes experimental reactor physics measurements at PARR using the in-core neutron detectors. Rhodium self powered neutron detectors (SPND) were used in the PARR core and several measurements were made aimed at detector calibration, response time determination and neutron flux measurements. The detectors were calibrated at low power using gold foils and full power by the thermal channel. Based on this calibration it was observed that the detector response remains almost linear throughout the power range. The self powered detectors were used for on-line determination of absolute neutron flux in the core as well as the spatial distribution of the neutron flux or reactor power. The total response time of the Rhodium detectors was experimentally determined to be about 5 minutes, which agrees well with the theoretical results. Because of longer response time of the SPND detectors it is not possible to use them in the reactor protection system.