Fusion Science and Technology / Volume 60 / Number 4 / November 2011 / Pages 1288-1291
Environmental and Organically Bound Tritium / Proceedings of the Ninth International Conference on Tritium Science and Technology (Part 2)
This study is devoted to the collection and robust analysis of 2008-2009 field data pertaining to airborne tritium transfer in potato and tomato plants subject to continuous releases. The study is a part of implementation and validation of tritium transfer model ported to Canadian LAnd Surface Scheme (CLASS), which has been recently extended towards plant phenomenology in Canadian Terrestrial Ecosystem Model (CTEM+CLASS v.2.7). The initial validation has been performed for ratios of organic to free-water tritium in plant tissues (OBT/HTO ratios) retrieved from the simple off-line tritium uptake and re-emission routine assessed against historical OBT/HTO ratio datasets. The observed underestimate of high OBT/HTO ratios in this simple model warrants deployment of CTEM+CLASS and makes it necessary to focus the next experimental validation effort at tritium re-emission phase. The concentration of HTO in the upper soil layer, in the different parts of vegetation and in the air has been assessed. The sampling was performed on weekly and hourly scales, in the latter case with emphasis on a night-time period. The process of uptake from atmosphere has been clarified using plants grown on the clean tarp-covered soil at Acid Rain Site of Chalk River Laboratories (CRL), which dumped the root uptake pathway. The processes of root uptake and re-emission from plant were clarified at the irrigated Perch Lake site of CRL. Auxiliary environmental drivers and site-specific data were collected according to format of inputs and parameterization of CTEM+CLASS.