The TOCATTA-χ model for assessing 14C transfers to grass: an evaluation for atmospheric operational releases from nuclear facilities

► We model 14C transfer from the atmosphere to grass near AREVA-NC reprocessing plant. ► A model based solely on the sap 14C activity and mean turn-over time is considered. ► Results are consistent with observations on both managed and poorly managed fields. ► The mean turn-over time for 14C within the plant accounts for management practices. ► This model could be applied to case studies but uncertainties should be considered.