Fig. 7. Simulated tritiated water vapor (³HHO_g) concentrations in units of Bq kg^–1 of water in the gas phase for the reference model simulation at time = 40 yr. Simulated ³HHO_g concentration of 1 Bq kg^–1 migrated to a maximum horizontal extent (MHE) of 27 m from the vertical face of the source trench and a maximum vertical extent (MVE) of 18 m from the bottom of the source trench.