STUDY ON IDENTIFICATION OF MATERIALS IN FUEL DEBRIS AND WASTE BY NEUTRON INDUCED GAMMA RAY SPECTROSCOPY

Abstract

Neutron induced γ ray spectroscopy (NIGS) has been conducted for each material anticipated to be contained in retrieved fuel debris and waste from PCV units 1, 2, and 3 of 1F. At PFFF of JAEA, γ rays from capture reactions are measured from ²³⁹Pu and ²³⁸U contained in PuO₂ and UO₂ samples loaded in an accounting device, as well as fission prompt γ rays. Concurrently, γ rays from capture reactions in polyethylene, steel, aluminum tube, cadmium plates, which are components of the device, are identified. Additionally, capture γ rays are measured for samples of zirconium, copper, gadolinium, and concrete as well as de-excitation γ ray from inelastic scattering of ¹¹B in a boron carbide sample. Since we can identify those γ rays, material classification by NIGS is promising.