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DOE OSTI · 1504647

Developing Diagnostic Tools for Low-Burnup Reactor Samples

Jaffke, Patrick John·Byerly, Benjamin·Doyle, Jamie·Hayes-Sterbenz, Anna Catherine·Jungman, Gerard·Myers, Steven Charles·Olson, Angela Christine·Porterfield, Donivan R.·Tandon, Lav
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Abstract

We test common neutron fluence diagnostics in the very-low-burnup regime for natural uranium reactor samples. The fluence diagnostics considered are the uranium isotopics ratios 235 U / 238 U and 236 U/ 235 U, for which we find that simple analytic formulas agree well with full reactor simulation predictions. Both ratios agree reasonably well with one another for fluences in the (mid -10 19 ) - n/cm 2 range. However, below about 10 19 n/cm 2 , the concentrations of 236 U are found to be sufficiently low that the measured 236 U/ 235 U ratios become unreliable. We also derive and test diagnostics to determine the cooling times in situations where very low burnup and very long cooling times render many standard diagnostics impractical, such as the 241 Am / 241 Pu ratio. Here, we find that using several fragment ratios is necessary to detect the presence of systematic errors such as fractionation.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS

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BibTeXRIS

Jaffke, Patrick John, Byerly, Benjamin, Doyle, Jamie, Hayes-Sterbenz, Anna Catherine, Jungman, Gerard, Myers, Steven Charles, Olson, Angela Christine, Porterfield, Donivan R., Tandon, Lav. 2017-10-31. Developing Diagnostic Tools for Low-Burnup Reactor Samples. https://doi.org/10.1103/physrevapplied.8.044025

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