Use of PGNAA for analysis of boron-10 in integral fuel-burnable absorber nuclear fuel pellets

To compensate for the excess reactivity present in a nuclear reactor core at the beginning of core life, certain types of nuclear fuel pellets contain an integral "burnable absorber," which is a nuclide with a large thermal-neutron absorption cross section that is converted into a low-absorption cross section nuclide upon neutron absorption. Examples of burnable absorbers are boron and gadolinium. The manufacturing process of pellets with a boron burnable-absorber coating includes monitoring of pellet boron content through batch chemical analysis. This method is time-intensive, destructive, and produces radioactive waste as a byproduct. Consequently, a nondestructive method based on prompt gamma neutron activation analysis (PGNAA) is being evaluated for the analysis of boron-10 on the pellets. The design of a PGNAA system for this analysis will be discussed, and results of preliminary experimental tests conducted to evaluate sensitivity and to assess radiological dose exposure during operation will be presented.