ACTIVATION OF STRUCTURAL MATERIALS DUE TO RECOIL PROTONS IN LIGHT WATER REACTOR
NAIG Nuclear Research Laboratory
4-1, Ukishima-cho, Kawasaki-ku, Kawasaki, 210 Japan
The long-lived radioactivities of structural materials induced by recoil protons in BWR were estimated for land disposal of low level waste after reactor decommissioning. Products of interest are Mn-53, Nb-91, Nb-94, Tc-97, Sb-125, Lu-173 and Lu-174. Method of calculation of the proton spectrum in materials was presented. Program PEGASUS-P was developed by modifying PEGASUS, a preequilibrium and multistep evaporation theory code, to calculate proton reaction cross sections. The proton-induced activity is shown as not exceeding 1/1000 of that of a typical neutron induced activity of Ni-63 for cooling up to 1000 y after irradiation of 40 y in BWR.
KEYWORDS: BWR, recoil proton, induced activity, structural material, proton cross section