Reactor Power History from Fission Product Signatures

As a transparency aid for international verification processes it would be beneficial for international monitors to be able to independently verify a reactor fuel's operational history from fission product signatures released during fuel dissolutions. Previous efforts at power history verification from fission product signatures have been limited in scope and without significant success. Unique characteristics of some stable and radioactive nuclides such as variations in fission product yields from changing fissioning systems, changes in absorption cross-sections due to different neutron flux spectra, and the fission product half-lives create significant differences in the concentration of such nuclides as a result of varying reactor power histories. This paper discusses a method developed at Texas A&M University for determining reactor power history from trace fission product signatures using a combination of signatures. This system has been tested with simulated results from the TRANSLAT assembly simulation code and significant improvements in power history verification have been found.