Laser-Assisted Decontamination of Fuel Pins for Prototype Fast Breeder Reactor

Abstract

Decontamination of fuel pins is an important process step in nuclear fuel fabrication. Decontamination assumes greater significance with respect to fuels containing plutonium, owing to both plutonium’s high radiotoxicity arising from its long biological half-life and its relatively short radioactive half-life. The advantages of using a laser to decontaminate such radioactive surfaces over conventional cleaning techniques are well recognized. This paper describes detailed process optimization and field implementation of laser-assisted decontamination of fuel pins of the Prototype Fast Breeder Reactor (PFBR). A short-pulsed Nd-YAG laser has been effectively used to decontaminate the fuel pins by exposing their outer surface to laser radiation of an appropriate fluence. The laser parameters were controlled to achieve the required cleaning without causing any clad surface damage. Achievement of such was confirmed by evaluating the laser-cleaned surface using scanning electron microscopy, chemical composition studies by electron probe microanalysis, and Vicker’s microhardness test.