Feasibility of 106Ru Peak Measurement for MOX Fuel Burnup Analysis
Simulations were performed using ORIGEN-ARP to investigate ¹³⁷Cs and ¹⁰⁶Ru-¹⁰⁶Rh as suitable fission products for non-destructive analysis of irradiated MOX. The simulations confirm that both ¹³⁷Cs and ¹⁰⁶Ru will provide a linear correlation with burnup when exclusively applied to MOX fuel assemblies. Moreover, ¹⁰⁶Ru can also be used in conjunction with cesium to form a ratio almost independent of enrichment and power history. Simulations were conducted using three different uranium enrichments and one MOX enrichment over a burnup range of 20,000-60,000 MWD/MTHM. Comparison of the three uranium enrichments indicates the ¹⁰⁶Ru ratio is consistent in predicting burnup with a maximum standard deviation of 0.046. Two MOX cases were simulated confirming operational history independence of ¹⁰⁶Ru in predicting total burnup. The ¹⁰⁶Ru burnup ratio also has the benefit of enabling distinction between UO₂ and MOX fuel because of its significantly larger (~11 times) fission yield from ²³⁹Pu. To investigate the detectability of ¹⁰⁶Ru and other cesium peaks, data was collected using a HPGe detector at the Missouri S&T nuclear reactor (MS&TR) beam port. Gamma spectra were obtained immediately following reactor shutdown with the most promising spectrums obtained 3-5 h after shutdown. Even for relatively high enrichment (~20%) fuel at MS&TR, cesium peaks were prominent and easily discernable from the intense Compton continuum. The ¹⁰⁶Ru peak was weak, though still distinguishable from the background, suggesting that with an appropriately designed collimator, suitable detector and electronics it might be feasible to reliably measure ¹⁰⁶Ru in even UO₂ fuel. For MOX and LEU LWR fuels one would expect a more intense ¹⁰⁶Ru signature. © 2010 Elsevier B.V. All rights reserved.
M. L. Dennis and S. Usman, "Feasibility of 106Ru Peak Measurement for MOX Fuel Burnup Analysis," Nuclear Engineering and Design, Elsevier, Jan 2010.
The definitive version is available at http://dx.doi.org/10.1016/j.nucengdes.2010.07.003
Mining and Nuclear Engineering
Article - Conference proceedings
© 2010 Elsevier, All rights reserved.