Some unique applications of solid state track recorder autoradiography in the nuclear industry

CR-39 solid state track recorder alpha autoradiography has been applied to the inspection of sectioned weld samples of parts containing plutonium. In addition to determining the amounts of plutonium present, information on the distribution and physical form of the plutonium has been obtained. In a separate application, autoradiographic methods developed previously for analysis of airborne actinide aerosols are extended to the analysis of fuel debris at TMI-2. Autoradiographic determination of the alpha decay rate and thermal neutron induced fission rate allows the 239 Pu/ 235 U ratio to be calculated on a particle-by-particle basis. This ratio is in turn dependent on local power density in the reactor core. Correlations of the 239 Pu/ 235 U ratio with particle size should provide useful data on mechanisms for core degradation and transport through the primary coolant system of the reactor.