Absolute Integral Fission Product Chain Yield Measurements at NCERC
ORAL
Abstract
Fission product chain yields were historically determined by chemical separation and beta counting of fissile samples irradiated in carefully controlled fission chamber experiments. These measurements provided the means to extract the absolute fission product yields (yield per fission, or Yi/f for the ith fission product) that are included in the international nuclear data libraries, and ultimately used to model and characterize multiplying systems. However, re-evaluations conducted in the late 2010s for neutron-induced fission of 235U and 239Pu highlighted disagreement between several important measurements used in the data library evaluations.
In this presentation we will highlight recent activities to address discrepancies and data gaps using energy-integral measurements for 235U and 239Pu. This work relies on the historical combination of fission chambers and radiochemical analyses of fissile samples irradiated on the critical assemblies at the National Criticality Experiments Research Center (NCERC) at the Nevada National Security Site. Details will be provided on the design and performance of the fission chambers, along with the results from irradiations on the Flattop and Godiva critical assemblies. We will conclude with an outline of our plans to complete the work over the next several years.
In this presentation we will highlight recent activities to address discrepancies and data gaps using energy-integral measurements for 235U and 239Pu. This work relies on the historical combination of fission chambers and radiochemical analyses of fissile samples irradiated on the critical assemblies at the National Criticality Experiments Research Center (NCERC) at the Nevada National Security Site. Details will be provided on the design and performance of the fission chambers, along with the results from irradiations on the Flattop and Godiva critical assemblies. We will conclude with an outline of our plans to complete the work over the next several years.
*This work was funded in part by the Office of Defense Nuclear Nonproliferation Research and Development of the U.S. Department of Energy’s National Nuclear Security Administration.This work made use of the National Criticality Experiments Research Center, supported by the Department of Energy's Nuclear Criticality Safety program with financial support from the National Nuclear Security Administration's Office of the Chief of Defense Nuclear Safety.
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Presenters
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Todd A Bredeweg
- Los Alamos National Laboratory
- Los Alamos Natl Lab