Determination of Gamma-Ray-Induced Displacement Rates
SourceTo define the gamma-ray component of the radiation field in light water reactor (LWR) pressure vessel (PV) environments, gamma-ray spectrometry experiments were conducted in the low power PV mockup at the poolside critical assembly (PCA) at the Oak Ridge National Laboratory (ORNL). Gamma-ray displacement rates can be calculated directly from absolute electron spectra observed with the Janus probe gamma-ray spectrometry. Gamma-ray displacement results are presented for the 1/4-T, 1/2-T, and 3/4-T locations of the 12/13 and 4/12 simulated surveillance capsule (SSC) configurations. In addition, the gamma-ray displacement rate at the SSC location was inferred using thermoluminescent dosimeter (TLD) gamma-ray dosimetry results obtained in the 4/12 SSC configuration at the PCA. Compared with neutron-induced displacement rates, the calculated gamma-ray-induced displacement rates are small at all these LWR-PV locations. The ratio of gamma-ray-induced to neutron-induced displacement rates never exceeds roughly 5 × 10 -3.