The Use of Non Destructive Assay Measurements to Estimate Burnup and Plutonium Inventory in Pressurized Water Reactor Spent Fuel Assemblies

Nondestructive Assay Data Integration with the SKB-50 Assemblies - FY16 Update

“…A deuterium-tritium (DT) neutron generator produces the neutron burst on one side of the assembly while neutron detectors that only detect neutrons with an energy above 0.5 eV surround the assembly on the other three sides. (7) The Californium Interrogation Prompt Neutron (CIPN) [27] [28] technique will be tested with the hardware that was primarily designed for DDA by simply keeping the neutron generator on continuously for several seconds. With CIPN, the signal of interest is the difference between (a) the steady-state passive background count rate measured while the DT generator is turned off, and (b) the steady-state count rate that exists while the generator is on.…”

“…Because it is fairly common to find publications that state that 154 Eu decays to undetectable levels [35] with the current roughly 50 year cooled fuel, a brief discussion of the fundamental physics and the context for the accuracy of this statement are given here. A 45 GWd/tU, 4wt.%, 5 year cooled assembly emits approximately 4 x 10 13 1274 keV photons/s [7]. When this assembly is cooled to 70 years it emits approximately 2 x 10 11 1274 keV photons/s or 5 x 10 8 1274 keV photons/s per centimeter of axial length.…”

“…The research team is currently in the early phases of analyzing the passive gamma and total neutron data obtained with a Fork [3] [4] detector as well as spectral resolved data taken with a HPGe detector provided by Euratom. The NDA signal integration research conducted with simulated data as part of the NGSI-SF Project [5][6] [7] motivated the application of pattern recognition techniques, often called Data Mining techniques as a means of producing useful information in the context of the various technical goals.…”