In-Core Power Measurement Using SiC Semiconductor Detector

A SiC detector was fabricated and tested in harsh radiation environment of the High Flux Advanced Neutron Application Reactor (HANARO) reactor core at Korea Atomic Energy Research Institute (KAERI). A 4H-SiC with 30 µm thick epitaxial layer was used as the radiation sensor, and the detector was designed to be tolerable against thermal and radiation damages. Alpha response and I-V characteristics of fabricated SiC sensor was measured and detection performance of the SiC detector was evaluated in a neutron field of HANARO ex-core neutron irradiation facility. After preliminary tests, reactor power monitoring using the SiC detector was carried out by inserting it into the HANARO irradiation hole, IP-4. Radiation-induced current of the detector was recorded as reactor power increased up to 10 MWth. Maximum thermal and fast neutron fluxes were 9.4×1012 and 2.5×109 neutrons/cm2/sec, respectively, and total neutron fluence irradiated on the detector was 4.7×1016 neutrons/cm2. The detector showed good linearity of response up to the tested fluence, with R2 = 0.9997. Response speed of SiC detector was compared to that of a Rh self-powered neutron detector (SPND) in terms of signal saturation time. Averaged SiC detector saturation time was 12.8 seconds, approximately 11 times faster that of the Rh SPND.