  The 200-MeV electron linac of the National Synchrotron Radiation Laboratory
(NSRL) located in Hefei is one of the earliest high-energy electron linear
accelerators in China. The electrons are accelerated to 200 MeV by five
acceleration tubes and are collimated by scrapers. The scraper aperture is
smaller than the acceleration tube one, so some electrons hit the materials
when passing through them. These lost electrons cause induced radioactivity
mainly due to bremsstrahlung and photonuclear reaction. This paper describes a
study of induced radioactivity for the NSRL Linac using FLUKA simulations and
gamma-spectroscopy. The measurements showed that electrons were lost mainly at
the scraper. So the induced radioactivity of the NSRL Linac is mainly produced
here. The radionuclide types were simulated using the FLUKA Monte Carlo code
and the results were compared against measurements made with a High Purity
Germanium (HPGe) gamma spectrometer. The NSRL linac had been retired because of
upgrading last year. The removed components were used to study induced
radioactivity. The radionuclides confirmed by the measurement are: $^{57}$Ni,
$^{52}$Mn, $^{51}$Cr, $^{58}$Co, $^{56}$Co, $^{57}$Co, $^{54}$Mn, $^{60}$Co and
$^{22}$Na, the first eight nuclides of which are predicted by FLUKA simulation.
The research will provide the theoretical basis for the similar accelerator
decommissioning plan, and is significant for accelerator structure design,
material selection and radiation protection design.
