Evaluation of functional loss to radiation detector in tomographic device for spent-fuel inspection by high-energy photons and neutrons: A preliminary study

•High-dose irradiation by spent fuels can affect functions of the inspection device.•Function-loss of radiation detector was investigated for photon/neutron irradiation.•No significant function loss to the detector was observed with photon irradiation.•Signal noise was highly produced even only signal processing board was irradiated.•Considerable function loss was produced to the detector with neutron irradiation.