Verification of aquatic dilution factors for liquid effluents released from a nuclear power plant

Dilution factors for liquid effluents released from the Fermi 2 Power Plant into Lake Erie were verified using updated liquid effluent release data, and currently available aquatic dispersion models. A near-field dilution factor of 5 currently used by Fermi 2 appears to be a reasonable assumption as supported by two models and site-specific data. Previously assumed dilution factors for shoreline points outside the near field are of the same order of magnitude as those calculated by this study. The dilution factor of 77, currently used by Fermi 2, at the Monroe water intake point is very conservative when compared with values calculated by this study. More accurate values could be generated by tracer studies as recommended by Regulatory Guide 1.113. Such studies can predict plume behavior and are more accurate than aquatic models. These new values would probably be less conservative than those currently in use, and their use would make it less likely that Fermi 2 will reach technical specification limits for liquid effluent dose.