Measurement of inclusive photonuclear (γ,n) reaction cross section for ¹²⁹I

Abstract

Abstract. Long-life non-γ emitting radioactive wastes such as 129 I and 14 C are produced from nuclear waste facilities. The photonuclear reaction is supposed to be usable for measuring the quantity of such nuclides without destruction of waste drum. Photonuclear products of 128 I and 13 C emit gamma rays and their radiation can be easily detected by a Ge detector. In this study, the inclusive photonuclear reaction cross section of 129 I(γ,n) 128 I was measured by the use of bremsstrahlung photons from 30-MeV electron LINAC. The amount of produced 128 I was measured with an HPGe gamma-ray spectrometer. Experiments were analyzed for both (γ,n) and accompanying (n,γ) reactions. Flux calculations were performed by EGS and MCNP codes. The measured average activation cross section of 129 I(γ,n) 128 I is 0.096 ± 0.005 barn on the basis of 197 Au(γ,n) reaction value. The measured value agrees with the evaluated (IAEA photonuclear data library) cross section within a deviation of 17%. The cross section is usable for non-destructive measurement of the amount of 129 I in radioactive waste.