Document: NRC Regulatory Guide
Document ID: c9ebcbb0-96c4-4d29-be51-5acae9cc858a
Document Type: regulatory_guide
Title: Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of Implementing Appendix I (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.113
CFR Part: 
CFR Title: 

Content:
change with offshore waters that effectively removes pollutants from the shore zone. Possible physical mechanisms responsible for this behavior are discussed by Csanady (Refs. 25 and 26). Observations near pollutant discharges have shown a well-defined pollutant plume hugging the shoreline for several days, then relatively quick dispersal offshore, followed by redevelopment of the plume in the opposite direction. Throughout this sequence, the buildup of pollutant concentration in the vicinity of the discharge is small (Refs. 23 and 27). A stable coastal current of, say, 10 cm/sec that persists for about three days before reversal causes an upcoast or downcoast excursion of an effluent plume which is of the order of 25 Ikn (about 16 miles). In view of the above findings, it is'possible to construct a quasi-steady-state model valid for distances of about 25 Ikn and time scales on the order of a few days. For those cases in which lateral mixing and mass exchange occur during flow stagnation periods, extension of the model beyond these limits should provide conservative results. It should be emphasized, however, that knowledge of Great Lakes coastal circulation patterns is far from complete. The existing data base is inadequate to conclude that the behavior described above is applicable to the entire Great Lakes system. A general knowledge of near-shore current climatology is needed. It is therefore recommended that modeling efforts be accompanied by time series current measurements at the site. Such measurements should be of sufficient duration to resolve the important time scales of flow variability. Of particular importance are field studies to define the extent and frequency of near-shore fumigation occurring at a given site. (2) Analytical Models (a) Steady-State Model Analytical models of routine releases of liquid effluents along open coasts are usually based on Gaussian-like solutions to the steady-state diffusion equation. The form of each solution may differ