Reply to ''Comments on Radiation-damage Resistance In Phyllosilicate Minerals from First Principles and Implications For Radiocesium and Strontium Retention in Soils''

In this reply the authors address comments in Wampler (2017) regarding Sassi et al. (2016), the focus of which is on ab initio calculation of threshold displacement energies (TDEs) for atoms in vermiculite, and the relative probabilities for Frenkel-defect formation among atom types arising from radioisotopes of the kind in the contaminated soils at Fukushima. Wampler (2017) offers suggestions attacking the context and importance, from a knowledge base that appears deficient. Specifically, with regards to the concentration of fallout radioactivity in soils, the present authors show that for radiocesium at Fukushima, Wampler’s (2017) homogeneous dilution model fails to stand up against direct experimental measurements, and further provide references showing that the local concentrations of these ions at the sub-micrometer level may be much higher than would be predicted from homogenous assumptions. No cognizance of this readily available data is demonstrated in Wampler (2017). With regards to the more peripheral topic of absolute Frenkel-defect formation probabilities, Wampler (2017) argues against damage accumulation within any individual phyllosilicate grain from self-contained radiocesium an agreeable concept. Based on these data, however, the present authors suggest that the radiation volumes of radiocesiumbearing particles as dispersed in Fukushima soils are likely to be strongly overlapping and thus the question of their mutual interaction persists. The durability of radiocesium-phyllosilicate interactions over the long term, even in fallout scenarios, remains as a research frontier worthy of exploration.