Measurement of the neutron flux distribution in a research reactor by neutron activation analysis

The neutron flux distribution in the core region of the JRTR was measured through the neutron activation analysis method. Sample mount and a tool for withdrawing the sample mount were devised to irradiate the Au wires and foils. The measured data were compared with calculated values to confirm the reliability of the power distribution calculation. The reactor power during irradiation was estimated to be 9% lower than indications of power monitoring systems calibrated at around 10 μW. The measured transversal and axial neutron reaction rate distributions showed agreement within 1.32% difference with the calculated results.