Intake Technologies used at the Brunswick Steam Electric Plant to Achieve a Reduction in Impingement Mortality to a Level Similar to that of Closed Cycle

The Brunswick Steam Electric Plant (BSEP) is located near the mouth of the Cape Fear River Estuary in North Carolina.  The BSEP consist of two nuclear units.  Once-through cooling water is withdrawn from the estuary and discharged to the Atlantic Ocean.   To reduce impingement mortality, a fish diversion structure was built across the mouth of the intake canal in 1982 and a fish return system including traveling screens, spray wash, and return flume was completed in 1983.   Although reduced in scope and frequency in recent years, impingement monitoring has been conducted since the units came on line in 1977.  Survival studies of impinged organisms were conducted from 1984 to 1987.  Long-term data can be compared to baseline annual impingement to assess the effectiveness of the diversion structure in reducing impingement.   Survival results provide additional insight regarding the overall effectiveness of the diversion structure and return system together in reducing annual impingement mortality.  Reductions in the annual number of the historically dominant species impinged compared to baseline due to the fish diversion structure ranged from 55 % to 99 % depending on species.  When survival study results are included the reduction in annual impingement mortality due to both the fish diversion structure and return system ranges from 77 % to 99% depending on species.  Annual variability in the effectiveness of these mitigation technologies was evident.   However, mean annual reductions in impingement mortality ranged from 94 % to 99% for the historically dominant species.  Installation of the fish diversion structured resulted in a shift in species composition from primarily larger fin-fish to penaeid shrimp and blue crab (taxa exhibiting > 90% survival in the fish return system).  Use of these mitigation technologies can be used to achieve reductions in impingement mortality approaching that of closed cycle cooling for many species.