Resolution of Generic Safety Issues: Item B-40: Effects of Power Plant Entrainment on Plankton ( NUREG-0933, Main Report with Supplements 1–34 )
The effects of entrainment on phytoplankton and zooplankton populations are often minimal and occasionally beneficial. Numerous studies of the effects of entrainment on plankton organisms, phytoplankton, and zooplankton have shown impacts to be minimal and/or not significant. Studies have also shown that, even when entrainment mortality is high, the overall impacts may be minimal due to the fast reproductive and recovery time for many species -- a few hours for some phytoplankton to several days for zooplankton.
It has not been uncommon for utilities to have undertaken exhaustive and sometimes unnecessary preoperational and operational environmental monitoring programs. In view of the above points, it may be possible to reduce or eliminate studies of certain planktonic elements, perhaps on a site or regional basis. A study of these matters will form the basis for a staff position on monitoring requirements of plankton and entrainment programs. If the state of the art as defined in the study is adequate, perhaps intensive studies can be reduced, saving time and expense for both utilities and the NRC staff. This item is documented in NUREG-0471.3
This Environmental issue is addressed in environmental impact statements on a case-by-case basis.412 Thus, this item has been dropped from further consideration.